depmod: prevent module dependency files corruption due to parallel invocation.

[thirdparty/kmod.git] / tools / depmod.c

/*
 * kmod-depmod - calculate modules.dep  using libkmod.
 *
 * Copyright (C) 2011-2013  ProFUSION embedded systems
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <assert.h>
#include <ctype.h>
#include <dirent.h>
#include <errno.h>
#include <getopt.h>
#include <limits.h>
#include <regex.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/utsname.h>

#include <shared/array.h>
#include <shared/hash.h>
#include <shared/macro.h>
#include <shared/util.h>
#include <shared/scratchbuf.h>

#include <libkmod/libkmod-internal.h>

#undef ERR
#undef DBG

#include "kmod.h"

#define DEFAULT_VERBOSE LOG_WARNING
static int verbose = DEFAULT_VERBOSE;

static const char CFG_BUILTIN_KEY[] = "built-in";
static const char CFG_EXTERNAL_KEY[] = "external";
static const char *default_cfg_paths[] = {
        "/run/depmod.d",
        SYSCONFDIR "/depmod.d",
        "/lib/depmod.d",
        NULL
};

static const char cmdopts_s[] = "aAb:C:E:F:euqrvnP:wmVh";
static const struct option cmdopts[] = {
        { "all", no_argument, 0, 'a' },
        { "quick", no_argument, 0, 'A' },
        { "basedir", required_argument, 0, 'b' },
        { "config", required_argument, 0, 'C' },
        { "symvers", required_argument, 0, 'E' },
        { "filesyms", required_argument, 0, 'F' },
        { "errsyms", no_argument, 0, 'e' },
        { "unresolved-error", no_argument, 0, 'u' }, /* deprecated */
        { "quiet", no_argument, 0, 'q' }, /* deprecated */
        { "root", no_argument, 0, 'r' }, /* deprecated */
        { "verbose", no_argument, 0, 'v' },
        { "show", no_argument, 0, 'n' },
        { "dry-run", no_argument, 0, 'n' },
        { "symbol-prefix", required_argument, 0, 'P' },
        { "warn", no_argument, 0, 'w' },
        { "map", no_argument, 0, 'm' }, /* deprecated */
        { "version", no_argument, 0, 'V' },
        { "help", no_argument, 0, 'h' },
        { }
};

static void help(void)
{
        printf("Usage:\n"
                "\t%s -[aA] [options] [forced_version]\n"
                "\n"
                "If no arguments (except options) are given, \"depmod -a\" is assumed\n"
                "\n"
                "depmod will output a dependency list suitable for the modprobe utility.\n"
                "\n"
                "Options:\n"
                "\t-a, --all            Probe all modules\n"
                "\t-A, --quick          Only does the work if there's a new module\n"
                "\t-e, --errsyms        Report not supplied symbols\n"
                "\t-n, --show           Write the dependency file on stdout only\n"
                "\t-P, --symbol-prefix  Architecture symbol prefix\n"
                "\t-C, --config=PATH    Read configuration from PATH\n"
                "\t-v, --verbose        Enable verbose mode\n"
                "\t-w, --warn           Warn on duplicates\n"
                "\t-V, --version        show version\n"
                "\t-h, --help           show this help\n"
                "\n"
                "The following options are useful for people managing distributions:\n"
                "\t-b, --basedir=DIR    Use an image of a module tree.\n"
                "\t-F, --filesyms=FILE  Use the file instead of the\n"
                "\t                     current kernel symbols.\n"
                "\t-E, --symvers=FILE   Use Module.symvers file to check\n"
                "\t                     symbol versions.\n",
                program_invocation_short_name);
}

_printf_format_(1, 2)
static inline void _show(const char *fmt, ...)
{
        va_list args;

        if (verbose <= DEFAULT_VERBOSE)
                return;

        va_start(args, fmt);
        vfprintf(stdout, fmt, args);
        fflush(stdout);
        va_end(args);
}
#define SHOW(...) _show(__VA_ARGS__)


/* binary index write *************************************************/
#include <arpa/inet.h>
/* BEGIN: code from module-init-tools/index.c just modified to compile here.
 *
 * Original copyright:
 *   index.c: module index file shared functions for modprobe and depmod
 *   Copyright (C) 2008  Alan Jenkins <alan-jenkins@tuffmail.co.uk>.
 *
 *   These programs are free software; you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation; either version 2 of the License, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with these programs.  If not, see <http://www.gnu.org/licenses/>.
 */

/* see documentation in libkmod/libkmod-index.c */

#define INDEX_MAGIC 0xB007F457
#define INDEX_VERSION_MAJOR 0x0002
#define INDEX_VERSION_MINOR 0x0001
#define INDEX_VERSION ((INDEX_VERSION_MAJOR<<16)|INDEX_VERSION_MINOR)
#define INDEX_CHILDMAX 128

struct index_value {
        struct index_value *next;
        unsigned int priority;
        char value[0];
};

/* In-memory index (depmod only) */
struct index_node {
        char *prefix;           /* path compression */
        struct index_value *values;
        unsigned char first;    /* range of child nodes */
        unsigned char last;
        struct index_node *children[INDEX_CHILDMAX]; /* indexed by character */
};


/* Format of node offsets within index file */
enum node_offset {
        INDEX_NODE_FLAGS    = 0xF0000000, /* Flags in high nibble */
        INDEX_NODE_PREFIX   = 0x80000000,
        INDEX_NODE_VALUES = 0x40000000,
        INDEX_NODE_CHILDS   = 0x20000000,

        INDEX_NODE_MASK     = 0x0FFFFFFF, /* Offset value */
};

static struct index_node *index_create(void)
{
        struct index_node *node;

        node = NOFAIL(calloc(sizeof(struct index_node), 1));
        node->prefix = NOFAIL(strdup(""));
        node->first = INDEX_CHILDMAX;

        return node;
}

static void index_values_free(struct index_value *values)
{
        while (values) {
                struct index_value *value = values;

                values = value->next;
                free(value);
        }
}

static void index_destroy(struct index_node *node)
{
        int c;

        for (c = node->first; c <= node->last; c++) {
                struct index_node *child = node->children[c];

                if (child)
                        index_destroy(child);
        }
        index_values_free(node->values);
        free(node->prefix);
        free(node);
}

static void index__checkstring(const char *str)
{
        int i;

        for (i = 0; str[i]; i++) {
                int ch = str[i];

                if (ch >= INDEX_CHILDMAX)
                        CRIT("Module index: bad character '%c'=0x%x - only 7-bit ASCII is supported:"
                              "\n%s\n", (char) ch, (int) ch, str);
        }
}

static int index_add_value(struct index_value **values,
                                const char *value, unsigned int priority)
{
        struct index_value *v;
        int duplicate = 0;
        int len;

        /* report the presence of duplicate values */
        for (v = *values; v; v = v->next) {
                if (streq(v->value, value))
                        duplicate = 1;
        }

        /* find position to insert value */
        while (*values && (*values)->priority < priority)
                values = &(*values)->next;

        len = strlen(value);
        v = NOFAIL(calloc(sizeof(struct index_value) + len + 1, 1));
        v->next = *values;
        v->priority = priority;
        memcpy(v->value, value, len + 1);
        *values = v;

        return duplicate;
}

static int index_insert(struct index_node *node, const char *key,
                        const char *value, unsigned int priority)
{
        int i = 0; /* index within str */
        int ch;

        index__checkstring(key);
        index__checkstring(value);

        while(1) {
                int j; /* index within node->prefix */

                /* Ensure node->prefix is a prefix of &str[i].
                   If it is not already, then we must split node. */
                for (j = 0; node->prefix[j]; j++) {
                        ch = node->prefix[j];

                        if (ch != key[i+j]) {
                                char *prefix = node->prefix;
                                struct index_node *n;

                                /* New child is copy of node with prefix[j+1..N] */
                                n = NOFAIL(calloc(sizeof(struct index_node), 1));
                                memcpy(n, node, sizeof(struct index_node));
                                n->prefix = NOFAIL(strdup(&prefix[j+1]));

                                /* Parent has prefix[0..j], child at prefix[j] */
                                memset(node, 0, sizeof(struct index_node));
                                prefix[j] = '\0';
                                node->prefix = prefix;
                                node->first = ch;
                                node->last = ch;
                                node->children[ch] = n;

                                break;
                        }
                }
                /* j is now length of node->prefix */
                i += j;

                ch = key[i];
                if(ch == '\0')
                        return index_add_value(&node->values, value, priority);

                if (!node->children[ch]) {
                        struct index_node *child;

                        if (ch < node->first)
                                node->first = ch;
                        if (ch > node->last)
                                node->last = ch;
                        node->children[ch] = NOFAIL(calloc(sizeof(struct index_node), 1));

                        child = node->children[ch];
                        child->prefix = NOFAIL(strdup(&key[i+1]));
                        child->first = INDEX_CHILDMAX;
                        index_add_value(&child->values, value, priority);

                        return 0;
                }

                /* Descend into child node and continue */
                node = node->children[ch];
                i++;
        }
}

static int index__haschildren(const struct index_node *node)
{
        return node->first < INDEX_CHILDMAX;
}

/* Recursive post-order traversal

   Pre-order would make for better read-side buffering / readahead / caching.
   (post-order means you go backwards in the file as you descend the tree).
   However, index reading is already fast enough.
   Pre-order is simpler for writing, and depmod is already slow.
 */
static uint32_t index_write__node(const struct index_node *node, FILE *out)
{
        uint32_t *child_offs = NULL;
        int child_count = 0;
        long offset;

        if (!node)
                return 0;

        /* Write children and save their offsets */
        if (index__haschildren(node)) {
                const struct index_node *child;
                int i;

                child_count = node->last - node->first + 1;
                child_offs = NOFAIL(malloc(child_count * sizeof(uint32_t)));

                for (i = 0; i < child_count; i++) {
                        child = node->children[node->first + i];
                        child_offs[i] = htonl(index_write__node(child, out));
                }
        }

        /* Now write this node */
        offset = ftell(out);

        if (node->prefix[0]) {
                fputs(node->prefix, out);
                fputc('\0', out);
                offset |= INDEX_NODE_PREFIX;
        }

        if (child_count) {
                fputc(node->first, out);
                fputc(node->last, out);
                fwrite(child_offs, sizeof(uint32_t), child_count, out);
                offset |= INDEX_NODE_CHILDS;
        }

        free(child_offs);

        if (node->values) {
                const struct index_value *v;
                unsigned int value_count;
                uint32_t u;

                value_count = 0;
                for (v = node->values; v != NULL; v = v->next)
                        value_count++;
                u = htonl(value_count);
                fwrite(&u, sizeof(u), 1, out);

                for (v = node->values; v != NULL; v = v->next) {
                        u = htonl(v->priority);
                        fwrite(&u, sizeof(u), 1, out);
                        fputs(v->value, out);
                        fputc('\0', out);
                }
                offset |= INDEX_NODE_VALUES;
        }

        return offset;
}

static void index_write(const struct index_node *node, FILE *out)
{
        long initial_offset, final_offset;
        uint32_t u;

        u = htonl(INDEX_MAGIC);
        fwrite(&u, sizeof(u), 1, out);
        u = htonl(INDEX_VERSION);
        fwrite(&u, sizeof(u), 1, out);

        /* Second word is reserved for the offset of the root node */
        initial_offset = ftell(out);
        assert(initial_offset >= 0);
        u = 0;
        fwrite(&u, sizeof(uint32_t), 1, out);

        /* Dump trie */
        u = htonl(index_write__node(node, out));

        /* Update first word */
        final_offset = ftell(out);
        assert(final_offset >= 0);
        (void)fseek(out, initial_offset, SEEK_SET);
        fwrite(&u, sizeof(uint32_t), 1, out);
        (void)fseek(out, final_offset, SEEK_SET);
}

/* END: code from module-init-tools/index.c just modified to compile here.
 */

/* configuration parsing **********************************************/
struct cfg_override {
        struct cfg_override *next;
        size_t len;
        char path[];
};

enum search_type {
        SEARCH_PATH,
        SEARCH_BUILTIN,
        SEARCH_EXTERNAL
};

struct cfg_search {
        struct cfg_search *next;
        enum search_type type;
        size_t len;
        char path[];
};

struct cfg_external {
        struct cfg_external *next;
        size_t len;
        char path[];
};

struct cfg {
        const char *kversion;
        char dirname[PATH_MAX];
        size_t dirnamelen;
        char sym_prefix;
        uint8_t check_symvers;
        uint8_t print_unknown;
        uint8_t warn_dups;
        struct cfg_override *overrides;
        struct cfg_search *searches;
        struct cfg_external *externals;
};

static enum search_type cfg_define_search_type(const char *path)
{
        if (streq(path, CFG_BUILTIN_KEY))
                return SEARCH_BUILTIN;
        if (streq(path, CFG_EXTERNAL_KEY))
                return SEARCH_EXTERNAL;
        return SEARCH_PATH;
}

static int cfg_search_add(struct cfg *cfg, const char *path)
{
        struct cfg_search *s;
        size_t len;
        enum search_type type;

        type = cfg_define_search_type(path);

        if (type != SEARCH_PATH)
                len = 0;
        else
                len = strlen(path) + 1;

        s = malloc(sizeof(struct cfg_search) + len);
        if (s == NULL) {
                ERR("search add: out of memory\n");
                return -ENOMEM;
        }
        s->type = type;
        if (type != SEARCH_PATH)
                s->len = 0;
        else {
                s->len = len - 1;
                memcpy(s->path, path, len);
        }

        DBG("search add: %s, search type=%hhu\n", path, type);

        s->next = cfg->searches;
        cfg->searches = s;
        return 0;
}

static void cfg_search_free(struct cfg_search *s)
{
        free(s);
}

static int cfg_override_add(struct cfg *cfg, const char *modname, const char *subdir)
{
        struct cfg_override *o;
        size_t modnamelen = strlen(modname);
        size_t subdirlen = strlen(subdir);
        size_t i;

        o = malloc(sizeof(struct cfg_override) + subdirlen + 1
                   + modnamelen + 1);
        if (o == NULL) {
                ERR("override add: out of memory\n");
                return -ENOMEM;
        }
        memcpy(o->path, subdir, subdirlen);
        i = subdirlen;
        o->path[i] = '/';
        i++;

        memcpy(o->path + i, modname, modnamelen);
        i += modnamelen;
        o->path[i] = '\0'; /* no extension, so we can match .ko/.ko.gz */

        o->len = i;

        DBG("override add: %s\n", o->path);

        o->next = cfg->overrides;
        cfg->overrides = o;
        return 0;
}

static void cfg_override_free(struct cfg_override *o)
{
        free(o);
}

static int cfg_external_add(struct cfg *cfg, const char *path)
{
        struct cfg_external *ext;
        size_t len = strlen(path);

        ext = malloc(sizeof(struct cfg_external) + len + 1);
        if (ext == NULL) {
                ERR("external add: out of memory\n");
                return -ENOMEM;
        }

        strcpy(ext->path, path);
        ext->len = len;

        DBG("external add: %s\n", ext->path);

        ext->next = cfg->externals;
        cfg->externals = ext;
        return 0;
}

static void cfg_external_free(struct cfg_external *ext)
{
        free(ext);
}

static int cfg_kernel_matches(const struct cfg *cfg, const char *pattern)
{
        regex_t re;
        int status;

        /* old style */
        if (streq(pattern, "*"))
                return 1;

        if (regcomp(&re, pattern, REG_EXTENDED|REG_NOSUB) != 0)
                return 0;

        status = regexec(&re, cfg->kversion, 0, NULL, 0);
        regfree(&re);

        return status == 0;
}

static int cfg_file_parse(struct cfg *cfg, const char *filename)
{
        char *line;
        FILE *fp;
        unsigned int linenum = 0;
        int err;

        fp = fopen(filename, "r");
        if (fp == NULL) {
                err = -errno;
                ERR("file parse %s: %m\n", filename);
                return err;
        }

        while ((line = freadline_wrapped(fp, &linenum)) != NULL) {
                char *cmd, *saveptr;

                if (line[0] == '\0' || line[0] == '#')
                        goto done_next;

                cmd = strtok_r(line, "\t ", &saveptr);
                if (cmd == NULL)
                        goto done_next;

                if (streq(cmd, "search")) {
                        const char *sp;
                        while ((sp = strtok_r(NULL, "\t ", &saveptr)) != NULL) {
                                cfg_search_add(cfg, sp);
                        }
                } else if (streq(cmd, "override")) {
                        const char *modname = strtok_r(NULL, "\t ", &saveptr);
                        const char *version = strtok_r(NULL, "\t ", &saveptr);
                        const char *subdir = strtok_r(NULL, "\t ", &saveptr);

                        if (modname == NULL || version == NULL ||
                                        subdir == NULL)
                                goto syntax_error;

                        if (!cfg_kernel_matches(cfg, version)) {
                                INF("%s:%u: override kernel did not match %s\n",
                                    filename, linenum, version);
                                goto done_next;
                        }

                        cfg_override_add(cfg, modname, subdir);
                } else if (streq(cmd, "external")) {
                        const char *version = strtok_r(NULL, "\t ", &saveptr);
                        const char *dir = strtok_r(NULL, "\t ", &saveptr);

                        if (version == NULL || dir == NULL)
                                goto syntax_error;

                        if (!cfg_kernel_matches(cfg, version)) {
                                INF("%s:%u: external directory did not match %s\n",
                                    filename, linenum, version);
                                goto done_next;
                        }

                        cfg_external_add(cfg, dir);
                } else if (streq(cmd, "include")
                                || streq(cmd, "make_map_files")) {
                        INF("%s:%u: command %s not implemented yet\n",
                            filename, linenum, cmd);
                } else {
syntax_error:
                        ERR("%s:%u: ignoring bad line starting with '%s'\n",
                            filename, linenum, cmd);
                }

done_next:
                free(line);
        }

        fclose(fp);

        return 0;
}

static int cfg_files_filter_out(DIR *d, const char *dir, const char *name)
{
        size_t len = strlen(name);
        struct stat st;

        if (name[0] == '.')
                return 1;

        if (len < 6 || !streq(name + len - 5, ".conf")) {
                INF("All cfg files need .conf: %s/%s\n", dir, name);
                return 1;
        }

        fstatat(dirfd(d), name, &st, 0);
        if (S_ISDIR(st.st_mode)) {
                ERR("Directories inside directories are not supported: %s/%s\n",
                    dir, name);
                return 1;
        }

        return 0;
}

struct cfg_file {
        size_t dirlen;
        size_t namelen;
        const char *name;
        char path[];
};

static void cfg_file_free(struct cfg_file *f)
{
        free(f);
}

static int cfg_files_insert_sorted(struct cfg_file ***p_files, size_t *p_n_files,
                                        const char *dir, const char *name)
{
        struct cfg_file **files, *f;
        size_t i, n_files, namelen, dirlen;
        void *tmp;

        dirlen = strlen(dir);
        if (name != NULL)
                namelen = strlen(name);
        else {
                name = basename(dir);
                namelen = strlen(name);
                dirlen -= namelen + 1;
        }

        n_files = *p_n_files;
        files = *p_files;
        for (i = 0; i < n_files; i++) {
                int cmp = strcmp(name, files[i]->name);
                if (cmp == 0) {
                        DBG("Ignoring duplicate config file: %.*s/%s\n",
                            (int)dirlen, dir, name);
                        return -EEXIST;
                } else if (cmp < 0)
                        break;
        }

        f = malloc(sizeof(struct cfg_file) + dirlen + namelen + 2);
        if (f == NULL) {
                ERR("files insert sorted: out of memory\n");
                return -ENOMEM;
        }

        tmp = realloc(files, sizeof(struct cfg_file *) * (n_files + 1));
        if (tmp == NULL) {
                ERR("files insert sorted: out of memory\n");
                free(f);
                return -ENOMEM;
        }
        *p_files = files = tmp;

        if (i < n_files) {
                memmove(files + i + 1, files + i,
                        sizeof(struct cfg_file *) * (n_files - i));
        }
        files[i] = f;

        f->dirlen = dirlen;
        f->namelen = namelen;
        f->name = f->path + dirlen + 1;
        memcpy(f->path, dir, dirlen);
        f->path[dirlen] = '/';
        memcpy(f->path + dirlen + 1, name, namelen);
        f->path[dirlen + 1 + namelen] = '\0';

        *p_n_files = n_files + 1;
        return 0;
}

/*
 * Insert configuration files ignoring duplicates
 */
static int cfg_files_list(struct cfg_file ***p_files, size_t *p_n_files,
                                const char *path)
{
        struct dirent *dent;
        DIR *d;
        int err = 0;
        struct stat st;

        if (stat(path, &st) != 0) {
                err = -errno;
                DBG("could not stat '%s': %m\n", path);
                return err;
        }

        if (!S_ISDIR(st.st_mode)) {
                cfg_files_insert_sorted(p_files, p_n_files, path, NULL);
                return 0;
        }

        d = opendir(path);
        if (d == NULL) {
                ERR("files list %s: %m\n", path);
                return -EINVAL;
        }

        for (dent = readdir(d); dent != NULL; dent = readdir(d)) {
                if (cfg_files_filter_out(d, path, dent->d_name))
                        continue;

                cfg_files_insert_sorted(p_files, p_n_files, path, dent->d_name);
        }

        closedir(d);
        DBG("parsed configuration files from %s\n", path);
        return err;
}

static int cfg_load(struct cfg *cfg, const char * const *cfg_paths)
{
        size_t i, n_files = 0;
        struct cfg_file **files = NULL;

        if (cfg_paths == NULL)
                cfg_paths = default_cfg_paths;

        for (i = 0; cfg_paths[i] != NULL; i++)
                cfg_files_list(&files, &n_files, cfg_paths[i]);

        for (i = 0; i < n_files; i++) {
                struct cfg_file *f = files[i];
                cfg_file_parse(cfg, f->path);
                cfg_file_free(f);
        }
        free(files);

        /* For backward compatibility add "updates" to the head of the search
         * list here. But only if there was no "search" option specified.
         */
        if (cfg->searches == NULL)
                cfg_search_add(cfg, "updates");

        return 0;
}

static void cfg_free(struct cfg *cfg)
{
        while (cfg->overrides) {
                struct cfg_override *tmp = cfg->overrides;
                cfg->overrides = cfg->overrides->next;
                cfg_override_free(tmp);
        }

        while (cfg->searches) {
                struct cfg_search *tmp = cfg->searches;
                cfg->searches = cfg->searches->next;
                cfg_search_free(tmp);
        }

        while (cfg->externals) {
                struct cfg_external *tmp = cfg->externals;
                cfg->externals = cfg->externals->next;
                cfg_external_free(tmp);
        }
}


/* depmod calculations ***********************************************/
struct vertex;
struct mod {
        struct kmod_module *kmod;
        char *path;
        const char *relpath; /* path relative to '$ROOT/lib/modules/$VER/' */
        char *uncrelpath; /* same as relpath but ending in .ko */
        struct kmod_list *info_list;
        struct kmod_list *dep_sym_list;
        struct array deps; /* struct symbol */
        size_t baselen; /* points to start of basename/filename */
        size_t modnamesz;
        int sort_idx; /* sort index using modules.order */
        int dep_sort_idx; /* topological sort index */
        uint16_t idx; /* index in depmod->modules.array */
        uint16_t users; /* how many modules depend on this one */
        bool visited; /* helper field to report cycles */
        struct vertex *vertex; /* helper field to report cycles */
        char modname[];
};

struct symbol {
        struct mod *owner;
        uint64_t crc;
        char name[];
};

struct depmod {
        const struct cfg *cfg;
        struct kmod_ctx *ctx;
        struct array modules;
        struct hash *modules_by_uncrelpath;
        struct hash *modules_by_name;
        struct hash *symbols;
};

static void mod_free(struct mod *mod)
{
        DBG("free %p kmod=%p, path=%s\n", mod, mod->kmod, mod->path);
        array_free_array(&mod->deps);
        kmod_module_unref(mod->kmod);
        kmod_module_info_free_list(mod->info_list);
        kmod_module_dependency_symbols_free_list(mod->dep_sym_list);
        free(mod->uncrelpath);
        free(mod->path);
        free(mod);
}

static int mod_add_dependency(struct mod *mod, struct symbol *sym)
{
        int err;

        DBG("%s depends on %s %s\n", mod->path, sym->name,
            sym->owner != NULL ? sym->owner->path : "(unknown)");

        if (sym->owner == NULL)
                return 0;

        err = array_append_unique(&mod->deps, sym->owner);
        if (err == -EEXIST)
                return 0;
        if (err < 0)
                return err;

        sym->owner->users++;
        SHOW("%s needs \"%s\": %s\n", mod->path, sym->name, sym->owner->path);
        return 0;
}

static void symbol_free(struct symbol *sym)
{
        DBG("free %p sym=%s, owner=%p %s\n", sym, sym->name, sym->owner,
            sym->owner != NULL ? sym->owner->path : "");
        free(sym);
}

static int depmod_init(struct depmod *depmod, struct cfg *cfg,
                                                        struct kmod_ctx *ctx)
{
        int err = 0;

        depmod->cfg = cfg;
        depmod->ctx = ctx;

        array_init(&depmod->modules, 128);

        depmod->modules_by_uncrelpath = hash_new(512, NULL);
        if (depmod->modules_by_uncrelpath == NULL) {
                err = -errno;
                goto modules_by_uncrelpath_failed;
        }

        depmod->modules_by_name = hash_new(512, NULL);
        if (depmod->modules_by_name == NULL) {
                err = -errno;
                goto modules_by_name_failed;
        }

        depmod->symbols = hash_new(2048, (void (*)(void *))symbol_free);
        if (depmod->symbols == NULL) {
                err = -errno;
                goto symbols_failed;
        }

        return 0;

symbols_failed:
        hash_free(depmod->modules_by_name);
modules_by_name_failed:
        hash_free(depmod->modules_by_uncrelpath);
modules_by_uncrelpath_failed:
        return err;
}

static void depmod_shutdown(struct depmod *depmod)
{
        size_t i;

        hash_free(depmod->symbols);

        hash_free(depmod->modules_by_uncrelpath);

        hash_free(depmod->modules_by_name);

        for (i = 0; i < depmod->modules.count; i++)
                mod_free(depmod->modules.array[i]);
        array_free_array(&depmod->modules);

        kmod_unref(depmod->ctx);
}

static int depmod_module_add(struct depmod *depmod, struct kmod_module *kmod)
{
        const struct cfg *cfg = depmod->cfg;
        const char *modname, *lastslash;
        size_t modnamesz;
        struct mod *mod;
        int err;

        modname = kmod_module_get_name(kmod);
        modnamesz = strlen(modname) + 1;

        mod = calloc(1, sizeof(struct mod) + modnamesz);
        if (mod == NULL)
                return -ENOMEM;
        mod->kmod = kmod;
        mod->sort_idx = depmod->modules.count + 1;
        mod->dep_sort_idx = INT32_MAX;
        memcpy(mod->modname, modname, modnamesz);
        mod->modnamesz = modnamesz;

        array_init(&mod->deps, 4);

        mod->path = strdup(kmod_module_get_path(kmod));
        lastslash = strrchr(mod->path, '/');
        mod->baselen = lastslash - mod->path;
        if (strncmp(mod->path, cfg->dirname, cfg->dirnamelen) == 0 &&
                        mod->path[cfg->dirnamelen] == '/')
                mod->relpath = mod->path + cfg->dirnamelen + 1;
        else
                mod->relpath = NULL;

        err = hash_add_unique(depmod->modules_by_name, mod->modname, mod);
        if (err < 0) {
                ERR("hash_add_unique %s: %s\n", mod->modname, strerror(-err));
                goto fail;
        }

        if (mod->relpath != NULL) {
                size_t uncrelpathlen = lastslash - mod->relpath + modnamesz
                                       + strlen(KMOD_EXTENSION_UNCOMPRESSED);
                mod->uncrelpath = memdup(mod->relpath, uncrelpathlen + 1);
                mod->uncrelpath[uncrelpathlen] = '\0';
                err = hash_add_unique(depmod->modules_by_uncrelpath,
                                      mod->uncrelpath, mod);
                if (err < 0) {
                        ERR("hash_add_unique %s: %s\n",
                            mod->uncrelpath, strerror(-err));
                        hash_del(depmod->modules_by_name, mod->modname);
                        goto fail;
                }
        }

        DBG("add %p kmod=%p, path=%s\n", mod, kmod, mod->path);

        return 0;

fail:
        free(mod->uncrelpath);
        free(mod);
        return err;
}

static int depmod_module_del(struct depmod *depmod, struct mod *mod)
{
        DBG("del %p kmod=%p, path=%s\n", mod, mod->kmod, mod->path);

        if (mod->uncrelpath != NULL)
                hash_del(depmod->modules_by_uncrelpath, mod->uncrelpath);

        hash_del(depmod->modules_by_name, mod->modname);

        mod_free(mod);
        return 0;
}

static const char *search_to_string(const struct cfg_search *s)
{
        switch(s->type) {
        case SEARCH_EXTERNAL:
                return "external";
        case SEARCH_BUILTIN:
                return "built-in";
        default:
                return s->path;
        }
}

static bool depmod_is_path_starts_with(const char *path,
                                       size_t pathlen,
                                       const char *prefix,
                                       size_t prefix_len)
{
        if (pathlen <= prefix_len)
                return false;
        if (path[prefix_len] != '/')
                return false;
        if (memcmp(path, prefix, prefix_len) != 0)
                return false;

        return true;
}

/* returns if existing module @mod is higher priority than newpath.
 * note this is the inverse of module-init-tools is_higher_priority()
 */
static int depmod_module_is_higher_priority(const struct depmod *depmod, const struct mod *mod, size_t baselen, size_t namelen, size_t modnamelen, const char *newpath)
{
        const struct cfg *cfg = depmod->cfg;
        const struct cfg_override *ov;
        const struct cfg_search *se;
        const struct cfg_external *ext;

        /* baselen includes the last '/' and mod->baselen doesn't. So it's
         * actually correct to use modnamelen in the first and modnamesz in
         * the latter */
        size_t newlen = baselen + modnamelen;
        size_t oldlen = mod->baselen + mod->modnamesz;
        const char *oldpath = mod->path;
        int i, bprio = -1, oldprio = -1, newprio = -1;
        size_t relnewlen = 0;
        size_t reloldlen = 0;
        const char *relnewpath = NULL;
        const char *reloldpath = NULL;

        DBG("comparing priorities of %s and %s\n",
            oldpath, newpath);

        if (strncmp(newpath, cfg->dirname, cfg->dirnamelen) == 0) {
                relnewpath = newpath + cfg->dirnamelen + 1;
                relnewlen = newlen - (cfg->dirnamelen + 1);
        }
        if (strncmp(oldpath, cfg->dirname, cfg->dirnamelen) == 0) {
                reloldpath = oldpath + cfg->dirnamelen + 1;
                reloldlen = oldlen - (cfg->dirnamelen + 1);
        }

        for (ov = cfg->overrides; ov != NULL; ov = ov->next) {
                DBG("override %s\n", ov->path);
                if (relnewlen == ov->len &&
                    memcmp(ov->path, relnewpath, relnewlen) == 0)
                        return 0;
                if (reloldlen == ov->len &&
                    memcmp(ov->path, reloldpath, reloldlen) == 0)
                        return 1;
        }

        for (i = 0, se = cfg->searches; se != NULL; se = se->next, i++) {
                DBG("search %s\n", search_to_string(se));
                if (se->type == SEARCH_BUILTIN)
                        bprio = i;
                else if (se->type == SEARCH_EXTERNAL) {
                        for (ext = cfg->externals; ext != NULL; ext = ext->next, i++) {
                                if (depmod_is_path_starts_with(newpath,
                                                               newlen,
                                                               ext->path,
                                                               ext->len))
                                        newprio = i;
                                if (depmod_is_path_starts_with(oldpath,
                                                               oldlen,
                                                               ext->path,
                                                               ext->len))
                                        oldprio = i;
                        }
                } else if (relnewlen > se->len && relnewpath[se->len] == '/' &&
                         memcmp(se->path, relnewpath, se->len) == 0)
                        newprio = i;
                else if (reloldlen > se->len && reloldpath[se->len] == '/' &&
                         memcmp(se->path, reloldpath, se->len) == 0)
                        oldprio = i;
        }

        if (newprio < 0)
                newprio = bprio;
        if (oldprio < 0)
                oldprio = bprio;

        DBG("priorities: built-in: %d, old: %d, new: %d\n",
            bprio, oldprio, newprio);

        return newprio <= oldprio;
}

static int depmod_modules_search_file(struct depmod *depmod, size_t baselen, size_t namelen, const char *path)
{
        struct kmod_module *kmod;
        struct mod *mod;
        const char *relpath;
        char modname[PATH_MAX];
        size_t modnamelen;
        int err;

        if (!path_ends_with_kmod_ext(path + baselen, namelen))
                return 0;

        if (path_to_modname(path, modname, &modnamelen) == NULL) {
                ERR("could not get modname from path %s\n", path);
                return -EINVAL;
        }

        relpath = path + depmod->cfg->dirnamelen + 1;
        DBG("try %s (%s)\n", relpath, modname);

        mod = hash_find(depmod->modules_by_name, modname);
        if (mod == NULL)
                goto add;

        if (depmod_module_is_higher_priority(depmod, mod, baselen,
                                                namelen, modnamelen, path)) {
                DBG("Ignored lower priority: %s, higher: %s\n",
                    path, mod->path);
                return 0;
        }

        DBG("Replace lower priority %s with new module %s\n",
            mod->relpath, relpath);
        err = depmod_module_del(depmod, mod);
        if (err < 0) {
                ERR("could not del module %s: %s\n", mod->path, strerror(-err));
                return err;
        }

add:
        err = kmod_module_new_from_path(depmod->ctx, path, &kmod);
        if (err < 0) {
                ERR("could not create module %s: %s\n", path, strerror(-err));
                return err;
        }

        err = depmod_module_add(depmod, kmod);
        if (err < 0) {
                ERR("could not add module %s: %s\n",
                    path, strerror(-err));
                kmod_module_unref(kmod);
                return err;
        }
        return 0;
}

static int depmod_modules_search_dir(struct depmod *depmod, DIR *d, size_t baselen, struct scratchbuf *s_path)
{
        struct dirent *de;
        int err = 0, dfd = dirfd(d);
        char *path;

        while ((de = readdir(d)) != NULL) {
                const char *name = de->d_name;
                size_t namelen;
                uint8_t is_dir;

                if (name[0] == '.' && (name[1] == '\0' ||
                                       (name[1] == '.' && name[2] == '\0')))
                        continue;
                if (streq(name, "build") || streq(name, "source"))
                        continue;
                namelen = strlen(name);
                if (scratchbuf_alloc(s_path, baselen + namelen + 2) < 0) {
                        err = -ENOMEM;
                        ERR("No memory\n");
                        continue;
                }

                path = scratchbuf_str(s_path);
                memcpy(path + baselen, name, namelen + 1);

                if (de->d_type == DT_REG)
                        is_dir = 0;
                else if (de->d_type == DT_DIR)
                        is_dir = 1;
                else {
                        struct stat st;
                        if (fstatat(dfd, name, &st, 0) < 0) {
                                ERR("fstatat(%d, %s): %m\n", dfd, name);
                                continue;
                        } else if (S_ISREG(st.st_mode))
                                is_dir = 0;
                        else if (S_ISDIR(st.st_mode))
                                is_dir = 1;
                        else {
                                ERR("unsupported file type %s: %o\n",
                                    path, st.st_mode & S_IFMT);
                                continue;
                        }
                }

                if (is_dir) {
                        int fd;
                        DIR *subdir;
                        fd = openat(dfd, name, O_RDONLY);
                        if (fd < 0) {
                                ERR("openat(%d, %s, O_RDONLY): %m\n",
                                    dfd, name);
                                continue;
                        }
                        subdir = fdopendir(fd);
                        if (subdir == NULL) {
                                ERR("fdopendir(%d): %m\n", fd);
                                close(fd);
                                continue;
                        }
                        path[baselen + namelen] = '/';
                        path[baselen + namelen + 1] = '\0';
                        err = depmod_modules_search_dir(depmod, subdir,
                                                        baselen + namelen + 1,
                                                        s_path);
                        closedir(subdir);
                } else {
                        err = depmod_modules_search_file(depmod, baselen,
                                                         namelen, path);
                }

                if (err < 0) {
                        path[baselen + namelen] = '\0';
                        ERR("failed %s: %s\n", path, strerror(-err));
                        err = 0; /* ignore errors */
                }
        }
        return err;
}

static int depmod_modules_search_path(struct depmod *depmod,
                                      const char *path)
{
        char buf[256];
        _cleanup_(scratchbuf_release) struct scratchbuf s_path_buf =
                SCRATCHBUF_INITIALIZER(buf);
        char *path_buf;
        DIR *d;
        size_t baselen;
        int err;

        d = opendir(path);
        if (d == NULL) {
                err = -errno;
                ERR("could not open directory %s: %m\n", path);
                return err;
        }

        baselen = strlen(path);

        if (scratchbuf_alloc(&s_path_buf, baselen + 2) < 0) {
                err = -ENOMEM;
                goto out;
        }
        path_buf = scratchbuf_str(&s_path_buf);

        memcpy(path_buf, path, baselen);
        path_buf[baselen] = '/';
        baselen++;
        path_buf[baselen] = '\0';

        err = depmod_modules_search_dir(depmod, d, baselen, &s_path_buf);
out:
        closedir(d);
        return err;
}

static int depmod_modules_search(struct depmod *depmod)
{
        int err;
        struct cfg_external *ext;

        err = depmod_modules_search_path(depmod, depmod->cfg->dirname);
        if (err < 0)
                return err;

        for (ext = depmod->cfg->externals; ext != NULL; ext = ext->next) {
                err = depmod_modules_search_path(depmod, ext->path);
                if (err < 0 && err == -ENOENT)
                        /* ignore external dir absense */
                        continue;
        }

        return 0;
}

static int mod_cmp(const void *pa, const void *pb) {
        const struct mod *a = *(const struct mod **)pa;
        const struct mod *b = *(const struct mod **)pb;
        return a->sort_idx - b->sort_idx;
}

static int depmod_modules_build_array(struct depmod *depmod)
{
        struct hash_iter module_iter;
        const void *v;
        int err;

        hash_iter_init(depmod->modules_by_name, &module_iter);
        while (hash_iter_next(&module_iter, NULL, &v)) {
                struct mod *mod = (struct mod *) v;
                mod->idx = depmod->modules.count;
                err = array_append(&depmod->modules, mod);
                if (err < 0)
                        return err;
        }

        return 0;
}

static void depmod_modules_sort(struct depmod *depmod)
{
        char order_file[PATH_MAX], line[PATH_MAX];
        FILE *fp;
        unsigned idx = 0, total = 0;

        snprintf(order_file, sizeof(order_file), "%s/modules.order",
                 depmod->cfg->dirname);
        fp = fopen(order_file, "r");
        if (fp == NULL) {
                WRN("could not open %s: %m\n", order_file);
                return;
        }

        while (fgets(line, sizeof(line), fp) != NULL) {
                size_t len = strlen(line);
                idx++;
                if (len == 0)
                        continue;
                if (line[len - 1] != '\n') {
                        ERR("%s:%u corrupted line misses '\\n'\n",
                                order_file, idx);
                        goto corrupted;
                }
        }
        total = idx + 1;
        idx = 0;
        fseek(fp, 0, SEEK_SET);
        while (fgets(line, sizeof(line), fp) != NULL) {
                size_t len = strlen(line);
                struct mod *mod;

                idx++;
                if (len == 0)
                        continue;
                line[len - 1] = '\0';

                mod = hash_find(depmod->modules_by_uncrelpath, line);
                if (mod == NULL)
                        continue;
                mod->sort_idx = idx - total;
        }

        array_sort(&depmod->modules, mod_cmp);
        for (idx = 0; idx < depmod->modules.count; idx++) {
                struct mod *m = depmod->modules.array[idx];
                m->idx = idx;
        }

corrupted:
        fclose(fp);
}

static int depmod_symbol_add(struct depmod *depmod, const char *name,
                                        bool prefix_skipped, uint64_t crc,
                                        const struct mod *owner)
{
        size_t namelen;
        int err;
        struct symbol *sym;

        if (!prefix_skipped && (name[0] == depmod->cfg->sym_prefix))
                name++;

        namelen = strlen(name) + 1;
        sym = malloc(sizeof(struct symbol) + namelen);
        if (sym == NULL)
                return -ENOMEM;

        sym->owner = (struct mod *)owner;
        sym->crc = crc;
        memcpy(sym->name, name, namelen);

        err = hash_add(depmod->symbols, sym->name, sym);
        if (err < 0) {
                free(sym);
                return err;
        }

        DBG("add %p sym=%s, owner=%p %s\n", sym, sym->name, owner,
            owner != NULL ? owner->path : "");

        return 0;
}

static struct symbol *depmod_symbol_find(const struct depmod *depmod,
                                                        const char *name)
{
        if (name[0] == '.') /* PPC64 needs this: .foo == foo */
                name++;
        if (name[0] == depmod->cfg->sym_prefix)
                name++;
        return hash_find(depmod->symbols, name);
}

static int depmod_load_modules(struct depmod *depmod)
{
        struct mod **itr, **itr_end;

        DBG("load symbols (%zd modules)\n", depmod->modules.count);

        itr = (struct mod **)depmod->modules.array;
        itr_end = itr + depmod->modules.count;
        for (; itr < itr_end; itr++) {
                struct mod *mod = *itr;
                struct kmod_list *l, *list = NULL;
                int err = kmod_module_get_symbols(mod->kmod, &list);
                if (err < 0) {
                        if (err == -ENOENT)
                                DBG("ignoring %s: no symbols\n", mod->path);
                        else
                                ERR("failed to load symbols from %s: %s\n",
                                                mod->path, strerror(-err));
                        goto load_info;
                }
                kmod_list_foreach(l, list) {
                        const char *name = kmod_module_symbol_get_symbol(l);
                        uint64_t crc = kmod_module_symbol_get_crc(l);
                        depmod_symbol_add(depmod, name, false, crc, mod);
                }
                kmod_module_symbols_free_list(list);

load_info:
                kmod_module_get_info(mod->kmod, &mod->info_list);
                kmod_module_get_dependency_symbols(mod->kmod,
                                                   &mod->dep_sym_list);
                kmod_module_unref(mod->kmod);
                mod->kmod = NULL;
        }

        DBG("loaded symbols (%zd modules, %u symbols)\n",
            depmod->modules.count, hash_get_count(depmod->symbols));

        return 0;
}

static int depmod_load_module_dependencies(struct depmod *depmod, struct mod *mod)
{
        const struct cfg *cfg = depmod->cfg;
        struct kmod_list *l;

        DBG("do dependencies of %s\n", mod->path);
        kmod_list_foreach(l, mod->dep_sym_list) {
                const char *name = kmod_module_dependency_symbol_get_symbol(l);
                uint64_t crc = kmod_module_dependency_symbol_get_crc(l);
                int bindtype = kmod_module_dependency_symbol_get_bind(l);
                struct symbol *sym = depmod_symbol_find(depmod, name);
                uint8_t is_weak = bindtype == KMOD_SYMBOL_WEAK;

                if (sym == NULL) {
                        DBG("%s needs (%c) unknown symbol %s\n",
                            mod->path, bindtype, name);
                        if (cfg->print_unknown && !is_weak)
                                WRN("%s needs unknown symbol %s\n",
                                    mod->path, name);
                        continue;
                }

                if (cfg->check_symvers && sym->crc != crc && !is_weak) {
                        DBG("symbol %s (%#"PRIx64") module %s (%#"PRIx64")\n",
                            sym->name, sym->crc, mod->path, crc);
                        if (cfg->print_unknown)
                                WRN("%s disagrees about version of symbol %s\n",
                                    mod->path, name);
                }

                mod_add_dependency(mod, sym);
        }

        return 0;
}

static int depmod_load_dependencies(struct depmod *depmod)
{
        struct mod **itr, **itr_end;

        DBG("load dependencies (%zd modules, %u symbols)\n",
            depmod->modules.count, hash_get_count(depmod->symbols));

        itr = (struct mod **)depmod->modules.array;
        itr_end = itr + depmod->modules.count;
        for (; itr < itr_end; itr++) {
                struct mod *mod = *itr;

                if (mod->dep_sym_list == NULL) {
                        DBG("ignoring %s: no dependency symbols\n", mod->path);
                        continue;
                }

                depmod_load_module_dependencies(depmod, mod);
        }

        DBG("loaded dependencies (%zd modules, %u symbols)\n",
            depmod->modules.count, hash_get_count(depmod->symbols));

        return 0;
}

static int dep_cmp(const void *pa, const void *pb)
{
        const struct mod *a = *(const struct mod **)pa;
        const struct mod *b = *(const struct mod **)pb;
        return a->dep_sort_idx - b->dep_sort_idx;
}

static void depmod_sort_dependencies(struct depmod *depmod)
{
        struct mod **itr, **itr_end;
        itr = (struct mod **)depmod->modules.array;
        itr_end = itr + depmod->modules.count;
        for (; itr < itr_end; itr++) {
                struct mod *m = *itr;
                if (m->deps.count > 1)
                        array_sort(&m->deps, dep_cmp);
        }
}

struct vertex {
        struct vertex *parent;
        struct mod *mod;
};

static struct vertex *vertex_new(struct mod *mod, struct vertex *parent)
{
        struct vertex *v;

        v = malloc(sizeof(*v));
        if (v == NULL)
                return NULL;

        v->parent = parent;
        v->mod = mod;
        return v;
}

static void depmod_list_remove_data(struct kmod_list **list, void *data)
{
        struct kmod_list *l;

        l = kmod_list_remove_data(*list, data);
        *list = l;
}

static int depmod_report_one_cycle(struct depmod *depmod,
                                   struct vertex *vertex,
                                   struct kmod_list **roots,
                                   struct hash *loop_set)
{
        const char sep[] = " -> ";
        size_t sz;
        char *buf;
        struct array reverse;
        int i;
        int n;
        struct vertex *v;
        int rc;

        array_init(&reverse, 3);

        sz = 0;
        for (v = vertex->parent, n = 0;
             v != NULL;
             v = v->parent, n++) {

                sz += v->mod->modnamesz - 1;
                array_append(&reverse, v);
                rc = hash_add(loop_set, v->mod->modname, NULL);
                if (rc != 0)
                        return rc;
                /* the hash will be freed where created */
        }
        sz += vertex->mod->modnamesz - 1;

        buf = malloc(sz + n * strlen(sep) + 1);

        sz = 0;
        for (i = reverse.count - 1; i >= 0; i--) {
                size_t len;

                v = reverse.array[i];

                len = v->mod->modnamesz - 1;
                memcpy(buf + sz, v->mod->modname, len);
                sz += len;
                strcpy(buf + sz, sep);
                sz += strlen(sep);

                depmod_list_remove_data(roots, v->mod);
        }
        strcpy(buf + sz, vertex->mod->modname);
        ERR("Cycle detected: %s\n", buf);

        free(buf);
        array_free_array(&reverse);

        return 0;
}

static int depmod_report_cycles_from_root(struct depmod *depmod,
                                          struct mod *root_mod,
                                          struct kmod_list **roots,
                                          void **stack,
                                          size_t stack_size,
                                          struct hash *loop_set)
{
        struct kmod_list *free_list = NULL; /* struct vertex */
        struct kmod_list *l;
        struct vertex *root;
        struct vertex *vertex;
        struct vertex *v;
        struct mod *m;
        struct mod **itr, **itr_end;
        size_t is;
        int ret = -ENOMEM;

        root = vertex_new(root_mod, NULL);
        if (root == NULL) {
                ERR("No memory to report cycles\n");
                goto out;
        }

        l = kmod_list_append(free_list, root);
        if (l == NULL) {
                ERR("No memory to report cycles\n");
                goto out;
        }
        free_list = l;

        is = 0;
        stack[is++] = (void *)root;

        while (is > 0) {
                vertex = stack[--is];
                m = vertex->mod;
                /*
                 * because of the topological sort we can start only
                 * from part of a loop or from a branch after a loop
                 */
                if (m->visited && m == root->mod) {
                        int rc;
                        rc = depmod_report_one_cycle(depmod, vertex,
                                                     roots, loop_set);
                        if (rc != 0) {
                                ret = rc;
                                goto out;
                        }
                        continue;
                }

                m->visited = true;
                if (m->deps.count == 0) {
                        /*
                         * boundary condition: if there is more than one
                         * single node branch (not a loop), it is
                         * recognized as a loop by the code above:
                         * m->visited because more then one,
                         * m == root->mod since it is a single node.
                         * So, prevent deeping into the branch second
                         * time.
                         */
                        depmod_list_remove_data(roots, m);

                        continue;
                }

                itr = (struct mod **) m->deps.array;
                itr_end = itr + m->deps.count;
                for (; itr < itr_end; itr++) {
                        struct mod *dep = *itr;
                        v = vertex_new(dep, vertex);
                        if (v == NULL) {
                                ERR("No memory to report cycles\n");
                                goto out;
                        }
                        assert(is < stack_size);
                        stack[is++] = v;

                        l = kmod_list_append(free_list, v);
                        if (l == NULL) {
                                ERR("No memory to report cycles\n");
                                goto out;
                        }
                        free_list = l;

                }
        }
        ret = 0;

out:
        while (free_list) {
                v = free_list->data;
                l = kmod_list_remove(free_list);
                free_list = l;
                free(v);
        }

        return ret;
}

static void depmod_report_cycles(struct depmod *depmod, uint16_t n_mods,
                                 uint16_t *users)
{
        int num_cyclic = 0;
        struct kmod_list *roots = NULL; /* struct mod */
        struct kmod_list *l;
        size_t n_r; /* local n_roots */
        int i;
        int err;
        _cleanup_free_ void **stack = NULL;
        struct mod *m;
        struct mod *root;
        struct hash *loop_set;

        for (i = 0, n_r = 0; i < n_mods; i++) {
                if (users[i] <= 0)
                        continue;
                m = depmod->modules.array[i];
                l = kmod_list_append(roots, m);
                if (l == NULL) {
                        ERR("No memory to report cycles\n");
                        goto out_list;
                }
                roots = l;
                n_r++;
        }

        stack = malloc(n_r * sizeof(void *));
        if (stack == NULL) {
                ERR("No memory to report cycles\n");
                goto out_list;
        }

        loop_set = hash_new(16, NULL);
        if (loop_set == NULL) {
                ERR("No memory to report cycles\n");
                goto out_list;
        }

        while (roots != NULL) {
                root = roots->data;
                l = kmod_list_remove(roots);
                roots = l;
                err = depmod_report_cycles_from_root(depmod,
                                                     root,
                                                     &roots,
                                                     stack, n_r, loop_set);
                if (err < 0)
                        goto out_hash;
        }

        num_cyclic = hash_get_count(loop_set);
        ERR("Found %d modules in dependency cycles!\n", num_cyclic);

out_hash:
        hash_free(loop_set);
out_list:
        while (roots != NULL) {
                /* no need to free data, come from outside */
                roots = kmod_list_remove(roots);
        }
}

static int depmod_calculate_dependencies(struct depmod *depmod)
{
        const struct mod **itrm;
        uint16_t *users, *roots, *sorted;
        uint16_t i, n_roots = 0, n_sorted = 0, n_mods = depmod->modules.count;
        int ret = 0;

        users = malloc(sizeof(uint16_t) * n_mods * 3);
        if (users == NULL)
                return -ENOMEM;
        roots = users + n_mods;
        sorted = roots + n_mods;

        DBG("calculate dependencies and ordering (%hu modules)\n", n_mods);

        assert(depmod->modules.count < UINT16_MAX);

        /* populate modules users (how many modules uses it) */
        itrm = (const struct mod **)depmod->modules.array;
        for (i = 0; i < n_mods; i++, itrm++) {
                const struct mod *m = *itrm;
                users[i] = m->users;
                if (users[i] == 0) {
                        roots[n_roots] = i;
                        n_roots++;
                }
        }

        /* topological sort (outputs modules without users first) */
        while (n_roots > 0) {
                const struct mod **itr_dst, **itr_dst_end;
                struct mod *src;
                uint16_t src_idx = roots[--n_roots];

                src = depmod->modules.array[src_idx];
                src->dep_sort_idx = n_sorted;
                sorted[n_sorted] = src_idx;
                n_sorted++;

                itr_dst = (const struct mod **)src->deps.array;
                itr_dst_end = itr_dst + src->deps.count;
                for (; itr_dst < itr_dst_end; itr_dst++) {
                        const struct mod *dst = *itr_dst;
                        uint16_t dst_idx = dst->idx;
                        assert(users[dst_idx] > 0);
                        users[dst_idx]--;
                        if (users[dst_idx] == 0) {
                                roots[n_roots] = dst_idx;
                                n_roots++;
                        }
                }
        }

        if (n_sorted < n_mods) {
                depmod_report_cycles(depmod, n_mods, users);
                ret = -EINVAL;
                goto exit;
        }

        depmod_sort_dependencies(depmod);

        DBG("calculated dependencies and ordering (%hu modules)\n", n_mods);

exit:
        free(users);
        return ret;
}

static int depmod_load(struct depmod *depmod)
{
        int err;

        err = depmod_load_modules(depmod);
        if (err < 0)
                return err;

        err = depmod_load_dependencies(depmod);
        if (err < 0)
                return err;

        err = depmod_calculate_dependencies(depmod);
        if (err < 0)
                return err;

        return 0;
}

static size_t mod_count_all_dependencies(const struct mod *mod)
{
        size_t i, count = 0;
        for (i = 0; i < mod->deps.count; i++) {
                const struct mod *d = mod->deps.array[i];
                count += 1 + mod_count_all_dependencies(d);
        }
        return count;
}

static int mod_fill_all_unique_dependencies(const struct mod *mod, const struct mod **deps, size_t n_deps, size_t *last)
{
        size_t i;
        int err = 0;
        for (i = 0; i < mod->deps.count; i++) {
                const struct mod *d = mod->deps.array[i];
                size_t j;
                uint8_t exists = 0;

                for (j = 0; j < *last; j++) {
                        if (deps[j] == d) {
                                exists = 1;
                                break;
                        }
                }

                if (exists)
                        continue;

                if (*last >= n_deps)
                        return -ENOSPC;
                deps[*last] = d;
                (*last)++;
                err = mod_fill_all_unique_dependencies(d, deps, n_deps, last);
                if (err < 0)
                        break;
        }
        return err;
}

static const struct mod **mod_get_all_sorted_dependencies(const struct mod *mod, size_t *n_deps)
{
        const struct mod **deps;
        size_t last = 0;

        *n_deps = mod_count_all_dependencies(mod);
        if (*n_deps == 0)
                return NULL;

        deps = malloc(sizeof(struct mod *) * (*n_deps));
        if (deps == NULL)
                return NULL;

        if (mod_fill_all_unique_dependencies(mod, deps, *n_deps, &last) < 0) {
                free(deps);
                return NULL;
        }

        qsort(deps, last, sizeof(struct mod *), dep_cmp);
        *n_deps = last;
        return deps;
}

static inline const char *mod_get_compressed_path(const struct mod *mod)
{
        if (mod->relpath != NULL)
                return mod->relpath;
        return mod->path;
}

static int output_deps(struct depmod *depmod, FILE *out)
{
        size_t i;

        for (i = 0; i < depmod->modules.count; i++) {
                const struct mod **deps, *mod = depmod->modules.array[i];
                const char *p = mod_get_compressed_path(mod);
                size_t j, n_deps;

                fprintf(out, "%s:", p);

                if (mod->deps.count == 0)
                        goto end;

                deps = mod_get_all_sorted_dependencies(mod, &n_deps);
                if (deps == NULL) {
                        ERR("could not get all sorted dependencies of %s\n", p);
                        goto end;
                }

                for (j = 0; j < n_deps; j++) {
                        const struct mod *d = deps[j];
                        fprintf(out, " %s", mod_get_compressed_path(d));
                }
                free(deps);
        end:
                putc('\n', out);
        }

        return 0;
}

static int output_deps_bin(struct depmod *depmod, FILE *out)
{
        struct index_node *idx;
        size_t i;

        if (out == stdout)
                return 0;

        idx = index_create();
        if (idx == NULL)
                return -ENOMEM;

        for (i = 0; i < depmod->modules.count; i++) {
                const struct mod **deps, *mod = depmod->modules.array[i];
                const char *p = mod_get_compressed_path(mod);
                char *line;
                size_t j, n_deps, linepos, linelen, slen;
                int duplicate;

                deps = mod_get_all_sorted_dependencies(mod, &n_deps);
                if (deps == NULL && n_deps > 0) {
                        ERR("could not get all sorted dependencies of %s\n", p);
                        continue;
                }

                linelen = strlen(p) + 1;
                for (j = 0; j < n_deps; j++) {
                        const struct mod *d = deps[j];
                        linelen += 1 + strlen(mod_get_compressed_path(d));
                }

                line = malloc(linelen + 1);
                if (line == NULL) {
                        free(deps);
                        ERR("modules.deps.bin: out of memory\n");
                        continue;
                }

                linepos = 0;
                slen = strlen(p);
                memcpy(line + linepos, p, slen);
                linepos += slen;
                line[linepos] = ':';
                linepos++;

                for (j = 0; j < n_deps; j++) {
                        const struct mod *d = deps[j];
                        const char *dp;

                        line[linepos] = ' ';
                        linepos++;

                        dp = mod_get_compressed_path(d);
                        slen = strlen(dp);
                        memcpy(line + linepos, dp, slen);
                        linepos += slen;
                }
                line[linepos] = '\0';

                duplicate = index_insert(idx, mod->modname, line, mod->idx);
                if (duplicate && depmod->cfg->warn_dups)
                        WRN("duplicate module deps:\n%s\n", line);
                free(line);
                free(deps);
        }

        index_write(idx, out);
        index_destroy(idx);

        return 0;
}

static int output_aliases(struct depmod *depmod, FILE *out)
{
        size_t i;

        fputs("# Aliases extracted from modules themselves.\n", out);

        for (i = 0; i < depmod->modules.count; i++) {
                const struct mod *mod = depmod->modules.array[i];
                struct kmod_list *l;

                kmod_list_foreach(l, mod->info_list) {
                        const char *key = kmod_module_info_get_key(l);
                        const char *value = kmod_module_info_get_value(l);

                        if (!streq(key, "alias"))
                                continue;

                        fprintf(out, "alias %s %s\n", value, mod->modname);
                }
        }

        return 0;
}

static int output_aliases_bin(struct depmod *depmod, FILE *out)
{
        struct index_node *idx;
        size_t i;

        if (out == stdout)
                return 0;

        idx = index_create();
        if (idx == NULL)
                return -ENOMEM;

        for (i = 0; i < depmod->modules.count; i++) {
                const struct mod *mod = depmod->modules.array[i];
                struct kmod_list *l;

                kmod_list_foreach(l, mod->info_list) {
                        const char *key = kmod_module_info_get_key(l);
                        const char *value = kmod_module_info_get_value(l);
                        char buf[PATH_MAX];
                        const char *alias;
                        int duplicate;

                        if (!streq(key, "alias"))
                                continue;

                        if (alias_normalize(value, buf, NULL) < 0) {
                                WRN("Unmatched bracket in %s\n", value);
                                continue;
                        }
                        alias = buf;

                        duplicate = index_insert(idx, alias, mod->modname,
                                                 mod->idx);
                        if (duplicate && depmod->cfg->warn_dups)
                                WRN("duplicate module alias:\n%s %s\n",
                                    alias, mod->modname);
                }
        }

        index_write(idx, out);
        index_destroy(idx);

        return 0;
}

static int output_softdeps(struct depmod *depmod, FILE *out)
{
        size_t i;

        fputs("# Soft dependencies extracted from modules themselves.\n", out);

        for (i = 0; i < depmod->modules.count; i++) {
                const struct mod *mod = depmod->modules.array[i];
                struct kmod_list *l;

                kmod_list_foreach(l, mod->info_list) {
                        const char *key = kmod_module_info_get_key(l);
                        const char *value = kmod_module_info_get_value(l);

                        if (!streq(key, "softdep"))
                                continue;

                        fprintf(out, "softdep %s %s\n", mod->modname, value);
                }
        }

        return 0;
}

static int output_symbols(struct depmod *depmod, FILE *out)
{
        struct hash_iter iter;
        const void *v;

        fputs("# Aliases for symbols, used by symbol_request().\n", out);

        hash_iter_init(depmod->symbols, &iter);

        while (hash_iter_next(&iter, NULL, &v)) {
                const struct symbol *sym = v;
                if (sym->owner == NULL)
                        continue;

                fprintf(out, "alias symbol:%s %s\n",
                                        sym->name, sym->owner->modname);
        }

        return 0;
}

static int output_symbols_bin(struct depmod *depmod, FILE *out)
{
        struct index_node *idx;
        char alias[1024];
        _cleanup_(scratchbuf_release) struct scratchbuf salias =
                SCRATCHBUF_INITIALIZER(alias);
        size_t baselen = sizeof("symbol:") - 1;
        struct hash_iter iter;
        const void *v;
        int ret = 0;

        if (out == stdout)
                return 0;

        idx = index_create();
        if (idx == NULL)
                return -ENOMEM;

        memcpy(alias, "symbol:", baselen);

        hash_iter_init(depmod->symbols, &iter);

        while (hash_iter_next(&iter, NULL, &v)) {
                int duplicate;
                const struct symbol *sym = v;
                size_t len;

                if (sym->owner == NULL)
                        continue;

                len = strlen(sym->name);

                if (scratchbuf_alloc(&salias, baselen + len + 1) < 0) {
                        ret = -ENOMEM;
                        goto err_scratchbuf;
                }
                memcpy(scratchbuf_str(&salias) + baselen, sym->name, len + 1);
                duplicate = index_insert(idx, alias, sym->owner->modname,
                                                        sym->owner->idx);

                if (duplicate && depmod->cfg->warn_dups)
                        WRN("duplicate module syms:\n%s %s\n",
                                                alias, sym->owner->modname);
        }

        index_write(idx, out);

err_scratchbuf:
        index_destroy(idx);

        if (ret < 0)
                ERR("output symbols: %s\n", strerror(-ret));

        return ret;
}

static int output_builtin_bin(struct depmod *depmod, FILE *out)
{
        FILE *in;
        struct index_node *idx;
        char infile[PATH_MAX], line[PATH_MAX], modname[PATH_MAX];

        if (out == stdout)
                return 0;

        snprintf(infile, sizeof(infile), "%s/modules.builtin",
                                                        depmod->cfg->dirname);
        in = fopen(infile, "r");
        if (in == NULL) {
                WRN("could not open %s: %m\n", infile);
                return 0;
        }

        idx = index_create();
        if (idx == NULL) {
                fclose(in);
                return -ENOMEM;
        }

        while (fgets(line, sizeof(line), in) != NULL) {
                if (!isalpha(line[0])) {
                        ERR("Invalid modules.builtin line: %s\n", line);
                        continue;
                }

                path_to_modname(line, modname, NULL);
                index_insert(idx, modname, "", 0);
        }

        index_write(idx, out);
        index_destroy(idx);
        fclose(in);

        return 0;
}

static int output_devname(struct depmod *depmod, FILE *out)
{
        size_t i;
        bool empty = true;

        for (i = 0; i < depmod->modules.count; i++) {
                const struct mod *mod = depmod->modules.array[i];
                struct kmod_list *l;
                const char *devname = NULL;
                char type = '\0';
                unsigned int major = 0, minor = 0;

                kmod_list_foreach(l, mod->info_list) {
                        const char *key = kmod_module_info_get_key(l);
                        const char *value = kmod_module_info_get_value(l);
                        unsigned int maj, min;

                        if (!streq(key, "alias"))
                                continue;

                        if (strstartswith(value, "devname:"))
                                devname = value + sizeof("devname:") - 1;
                        else if (sscanf(value, "char-major-%u-%u",
                                                &maj, &min) == 2) {
                                type = 'c';
                                major = maj;
                                minor = min;
                        } else if (sscanf(value, "block-major-%u-%u",
                                                &maj, &min) == 2) {
                                type = 'b';
                                major = maj;
                                minor = min;
                        }

                        if (type != '\0' && devname != NULL)
                                break;
                }

                if (devname != NULL) {
                        if (type != '\0') {
                                if (empty) {
                                        fputs("# Device nodes to trigger on-demand module loading.\n",
                                              out);
                                        empty = false;
                                }
                                fprintf(out, "%s %s %c%u:%u\n", mod->modname,
                                        devname, type, major, minor);
                        } else
                                ERR("Module '%s' has devname (%s) but "
                                    "lacks major and minor information. "
                                    "Ignoring.\n", mod->modname, devname);
                }
        }

        return 0;
}

static int depmod_output(struct depmod *depmod, FILE *out)
{
        static const struct depfile {
                const char *name;
                int (*cb)(struct depmod *depmod, FILE *out);
        } *itr, depfiles[] = {
                { "modules.dep", output_deps },
                { "modules.dep.bin", output_deps_bin },
                { "modules.alias", output_aliases },
                { "modules.alias.bin", output_aliases_bin },
                { "modules.softdep", output_softdeps },
                { "modules.symbols", output_symbols },
                { "modules.symbols.bin", output_symbols_bin },
                { "modules.builtin.bin", output_builtin_bin },
                { "modules.devname", output_devname },
                { }
        };
        const char *dname = depmod->cfg->dirname;
        int dfd, err = 0;
        struct timeval tv;

        gettimeofday(&tv, NULL);

        if (out != NULL)
                dfd = -1;
        else {
                dfd = open(dname, O_RDONLY);
                if (dfd < 0) {
                        err = -errno;
                        CRIT("could not open directory %s: %m\n", dname);
                        return err;
                }
        }

        for (itr = depfiles; itr->name != NULL; itr++) {
                FILE *fp = out;
                char tmp[NAME_MAX] = "";
                int r, ferr;

                if (fp == NULL) {
                        int flags = O_CREAT | O_EXCL | O_WRONLY;
                        int mode = 0644;
                        int fd;

                        snprintf(tmp, sizeof(tmp), "%s.%i.%li.%li", itr->name, getpid(),
                                        tv.tv_usec, tv.tv_sec);
                        fd = openat(dfd, tmp, flags, mode);
                        if (fd < 0) {
                                ERR("openat(%s, %s, %o, %o): %m\n",
                                    dname, tmp, flags, mode);
                                continue;
                        }
                        fp = fdopen(fd, "wb");
                        if (fp == NULL) {
                                ERR("fdopen(%d=%s/%s): %m\n", fd, dname, tmp);
                                close(fd);
                                continue;
                        }
                }

                r = itr->cb(depmod, fp);
                if (fp == out)
                        continue;

                ferr = ferror(fp) | fclose(fp);

                if (r < 0) {
                        if (unlinkat(dfd, tmp, 0) != 0)
                                ERR("unlinkat(%s, %s): %m\n", dname, tmp);

                        ERR("Could not write index '%s': %s\n", itr->name,
                                                                strerror(-r));
                        err = -errno;
                        break;
                }

                if (renameat(dfd, tmp, dfd, itr->name) != 0) {
                        err = -errno;
                        CRIT("renameat(%s, %s, %s, %s): %m\n",
                                        dname, tmp, dname, itr->name);
                        break;
                }

                if (ferr) {
                        err = -ENOSPC;
                        ERR("Could not create index '%s'. Output is truncated: %s\n",
                                                itr->name, strerror(-err));
                        break;
                }
        }

        if (dfd >= 0)
                close(dfd);

        return err;
}

static void depmod_add_fake_syms(struct depmod *depmod)
{
        /* __this_module is magic inserted by kernel loader. */
        depmod_symbol_add(depmod, "__this_module", true, 0, NULL);
        /* On S390, this is faked up too */
        depmod_symbol_add(depmod, "_GLOBAL_OFFSET_TABLE_", true, 0, NULL);
        /* On PowerPC64 ABIv2, .TOC. is more or less _GLOBAL_OFFSET_TABLE_ */
        if (!depmod_symbol_find(depmod, "TOC."))
                depmod_symbol_add(depmod, "TOC.", true, 0, NULL);
}

static int depmod_load_symvers(struct depmod *depmod, const char *filename)
{
        char line[10240];
        FILE *fp;
        unsigned int linenum = 0;

        fp = fopen(filename, "r");
        if (fp == NULL) {
                int err = -errno;
                DBG("load symvers: %s: %m\n", filename);
                return err;
        }
        DBG("load symvers: %s\n", filename);

        /* eg. "0xb352177e\tfind_first_bit\tvmlinux\tEXPORT_SYMBOL" */
        while (fgets(line, sizeof(line), fp) != NULL) {
                const char *ver, *sym, *where;
                char *verend;
                uint64_t crc;

                linenum++;

                ver = strtok(line, " \t");
                sym = strtok(NULL, " \t");
                where = strtok(NULL, " \t");
                if (!ver || !sym || !where)
                        continue;

                if (!streq(where, "vmlinux"))
                        continue;

                crc = strtoull(ver, &verend, 16);
                if (verend[0] != '\0') {
                        ERR("%s:%u Invalid symbol version %s: %m\n",
                            filename, linenum, ver);
                        continue;
                }

                depmod_symbol_add(depmod, sym, false, crc, NULL);
        }
        depmod_add_fake_syms(depmod);

        DBG("loaded symvers: %s\n", filename);

        fclose(fp);
        return 0;
}

static int depmod_load_system_map(struct depmod *depmod, const char *filename)
{
        const char ksymstr[] = "__ksymtab_";
        const size_t ksymstr_len = sizeof(ksymstr) - 1;
        char line[10240];
        FILE *fp;
        unsigned int linenum = 0;

        fp = fopen(filename, "r");
        if (fp == NULL) {
                int err = -errno;
                DBG("load System.map: %s: %m\n", filename);
                return err;
        }
        DBG("load System.map: %s\n", filename);

        /* eg. c0294200 R __ksymtab_devfs_alloc_devnum */
        while (fgets(line, sizeof(line), fp) != NULL) {
                char *p, *end;

                linenum++;

                p = strchr(line, ' ');
                if (p == NULL)
                        goto invalid_syntax;
                p++;
                p = strchr(p, ' ');
                if (p == NULL)
                        goto invalid_syntax;
                p++;

                /* skip prefix */
                if (p[0] == depmod->cfg->sym_prefix)
                        p++;

                /* Covers gpl-only and normal symbols. */
                if (strncmp(p, ksymstr, ksymstr_len) != 0)
                        continue;

                end = strchr(p, '\n');
                if (end != NULL)
                        *end = '\0';

                depmod_symbol_add(depmod, p + ksymstr_len, true, 0, NULL);
                continue;

        invalid_syntax:
                ERR("%s:%u: invalid line: %s\n", filename, linenum, line);
        }
        depmod_add_fake_syms(depmod);

        DBG("loaded System.map: %s\n", filename);

        fclose(fp);
        return 0;
}


static int depfile_up_to_date_dir(DIR *d, time_t mtime, size_t baselen, char *path)
{
        struct dirent *de;
        int err = 1, dfd = dirfd(d);

        while ((de = readdir(d)) != NULL) {
                const char *name = de->d_name;
                size_t namelen;
                struct stat st;

                if (name[0] == '.' && (name[1] == '\0' ||
                                       (name[1] == '.' && name[2] == '\0')))
                        continue;
                if (streq(name, "build") || streq(name, "source"))
                        continue;
                namelen = strlen(name);
                if (baselen + namelen + 2 >= PATH_MAX) {
                        path[baselen] = '\0';
                        ERR("path is too long %s%s\n", path, name);
                        continue;
                }

                if (fstatat(dfd, name, &st, 0) < 0) {
                        ERR("fstatat(%d, %s): %m\n", dfd, name);
                        continue;
                }

                if (S_ISDIR(st.st_mode)) {
                        int fd;
                        DIR *subdir;
                        memcpy(path + baselen, name, namelen + 1);
                        if (baselen + namelen + 2 + NAME_MAX >= PATH_MAX) {
                                ERR("directory path is too long %s\n", path);
                                continue;
                        }
                        fd = openat(dfd, name, O_RDONLY);
                        if (fd < 0) {
                                ERR("openat(%d, %s, O_RDONLY): %m\n",
                                    dfd, name);
                                continue;
                        }
                        subdir = fdopendir(fd);
                        if (subdir == NULL) {
                                ERR("fdopendir(%d): %m\n", fd);
                                close(fd);
                                continue;
                        }
                        path[baselen + namelen] = '/';
                        path[baselen + namelen + 1] = '\0';
                        err = depfile_up_to_date_dir(subdir, mtime,
                                                     baselen + namelen + 1,
                                                     path);
                        closedir(subdir);
                } else if (S_ISREG(st.st_mode)) {
                        if (!path_ends_with_kmod_ext(name, namelen))
                                continue;

                        memcpy(path + baselen, name, namelen + 1);
                        err = st.st_mtime <= mtime;
                        if (err == 0) {
                                DBG("%s %"PRIu64" is newer than %"PRIu64"\n",
                                    path, (uint64_t)st.st_mtime,
                                    (uint64_t)mtime);
                        }
                } else {
                        ERR("unsupported file type %s: %o\n",
                            path, st.st_mode & S_IFMT);
                        continue;
                }

                if (err == 0)
                        break; /* outdated! */
                else if (err < 0) {
                        path[baselen + namelen] = '\0';
                        ERR("failed %s: %s\n", path, strerror(-err));
                        err = 1; /* ignore errors */
                }
        }

        return err;
}

/* uptodate: 1, outdated: 0, errors < 0 */
static int depfile_up_to_date(const char *dirname)
{
        char path[PATH_MAX];
        DIR *d = opendir(dirname);
        struct stat st;
        size_t baselen;
        int err;
        if (d == NULL) {
                err = -errno;
                ERR("could not open directory %s: %m\n", dirname);
                return err;
        }

        if (fstatat(dirfd(d), "modules.dep", &st, 0) != 0) {
                err = -errno;
                ERR("could not fstatat(%s, modules.dep): %m\n", dirname);
                closedir(d);
                return err;
        }

        baselen = strlen(dirname);
        memcpy(path, dirname, baselen);
        path[baselen] = '/';
        baselen++;
        path[baselen] = '\0';

        err = depfile_up_to_date_dir(d, st.st_mtime, baselen, path);
        closedir(d);
        return err;
}

static int is_version_number(const char *version)
{
        unsigned int d1, d2;
        return (sscanf(version, "%u.%u", &d1, &d2) == 2);
}

static int do_depmod(int argc, char *argv[])
{
        FILE *out = NULL;
        int err = 0, all = 0, maybe_all = 0, n_config_paths = 0;
        _cleanup_free_ char *root = NULL;
        _cleanup_free_ const char **config_paths = NULL;
        const char *system_map = NULL;
        const char *module_symvers = NULL;
        const char *null_kmod_config = NULL;
        struct utsname un;
        struct kmod_ctx *ctx = NULL;
        struct cfg cfg;
        struct depmod depmod;

        memset(&cfg, 0, sizeof(cfg));
        memset(&depmod, 0, sizeof(depmod));

        for (;;) {
                int c, idx = 0;
                c = getopt_long(argc, argv, cmdopts_s, cmdopts, &idx);
                if (c == -1)
                        break;
                switch (c) {
                case 'a':
                        all = 1;
                        break;
                case 'A':
                        maybe_all = 1;
                        break;
                case 'b':
                        if (root)
                                free(root);
                        root = path_make_absolute_cwd(optarg);
                        break;
                case 'C': {
                        size_t bytes = sizeof(char *) * (n_config_paths + 2);
                        void *tmp = realloc(config_paths, bytes);
                        if (!tmp) {
                                fputs("Error: out-of-memory\n", stderr);
                                goto cmdline_failed;
                        }
                        config_paths = tmp;
                        config_paths[n_config_paths] = optarg;
                        n_config_paths++;
                        config_paths[n_config_paths] = NULL;
                        break;
                }
                case 'E':
                        module_symvers = optarg;
                        cfg.check_symvers = 1;
                        break;
                case 'F':
                        system_map = optarg;
                        break;
                case 'e':
                        cfg.print_unknown = 1;
                        break;
                case 'v':
                        verbose++;
                        break;
                case 'n':
                        out = stdout;
                        break;
                case 'P':
                        if (optarg[1] != '\0') {
                                CRIT("-P only takes a single char\n");
                                goto cmdline_failed;
                        }
                        cfg.sym_prefix = optarg[0];
                        break;
                case 'w':
                        cfg.warn_dups = 1;
                        break;
                case 'u':
                case 'q':
                case 'r':
                case 'm':
                        if (idx > 0)
                                WRN("Ignored deprecated option --%s\n",
                                    cmdopts[idx].name);
                        else
                                WRN("Ignored deprecated option -%c\n", c);

                        break;
                case 'h':
                        help();
                        return EXIT_SUCCESS;
                case 'V':
                        puts(PACKAGE " version " VERSION);
                        puts(KMOD_FEATURES);
                        return EXIT_SUCCESS;
                case '?':
                        goto cmdline_failed;
                default:
                        ERR("unexpected getopt_long() value '%c'.\n", c);
                        goto cmdline_failed;
                }
        }

        if (optind < argc) {
                if (!is_version_number(argv[optind])) {
                        ERR("Bad version passed %s\n", argv[optind]);
                        goto cmdline_failed;
                }
                cfg.kversion = argv[optind];
                optind++;
        } else {
                if (uname(&un) < 0) {
                        CRIT("uname() failed: %s\n", strerror(errno));
                        goto cmdline_failed;
                }
                cfg.kversion = un.release;
        }

        cfg.dirnamelen = snprintf(cfg.dirname, PATH_MAX,
                                  "%s/lib/modules/%s",
                                  root == NULL ? "" : root, cfg.kversion);

        if (optind == argc)
                all = 1;

        if (maybe_all) {
                if (out == stdout)
                        goto done;
                /* ignore up-to-date errors (< 0) */
                if (depfile_up_to_date(cfg.dirname) == 1)
                        goto done;
                all = 1;
        }

        ctx = kmod_new(cfg.dirname, &null_kmod_config);
        if (ctx == NULL) {
                CRIT("kmod_new(\"%s\", {NULL}) failed: %m\n", cfg.dirname);
                goto cmdline_failed;
        }

        log_setup_kmod_log(ctx, verbose);

        err = depmod_init(&depmod, &cfg, ctx);
        if (err < 0) {
                CRIT("depmod_init: %s\n", strerror(-err));
                goto depmod_init_failed;
        }
        ctx = NULL; /* owned by depmod */

        if (module_symvers != NULL) {
                err = depmod_load_symvers(&depmod, module_symvers);
                if (err < 0) {
                        CRIT("could not load %s: %s\n", module_symvers,
                             strerror(-err));
                        goto cmdline_failed;
                }
        } else if (system_map != NULL) {
                err = depmod_load_system_map(&depmod, system_map);
                if (err < 0) {
                        CRIT("could not load %s: %s\n", system_map,
                             strerror(-err));
                        goto cmdline_failed;
                }
        } else if (cfg.print_unknown) {
                WRN("-e needs -E or -F\n");
                cfg.print_unknown = 0;
        }

        if (all) {
                err = cfg_load(&cfg, config_paths);
                if (err < 0) {
                        CRIT("could not load configuration files\n");
                        goto cmdline_modules_failed;
                }
                err = depmod_modules_search(&depmod);
                if (err < 0) {
                        CRIT("could not search modules: %s\n", strerror(-err));
                        goto cmdline_modules_failed;
                }
        } else {
                int i;

                for (i = optind; i < argc; i++) {
                        const char *path = argv[i];
                        struct kmod_module *mod;

                        if (path[0] != '/') {
                                CRIT("%s: not absolute path.\n", path);
                                goto cmdline_modules_failed;
                        }

                        err = kmod_module_new_from_path(depmod.ctx, path, &mod);
                        if (err < 0) {
                                CRIT("could not create module %s: %s\n",
                                     path, strerror(-err));
                                goto cmdline_modules_failed;
                        }

                        err = depmod_module_add(&depmod, mod);
                        if (err < 0) {
                                CRIT("could not add module %s: %s\n",
                                     path, strerror(-err));
                                kmod_module_unref(mod);
                                goto cmdline_modules_failed;
                        }
                }
        }

        err = depmod_modules_build_array(&depmod);
        if (err < 0) {
                CRIT("could not build module array: %s\n",
                     strerror(-err));
                goto cmdline_modules_failed;
        }

        depmod_modules_sort(&depmod);
        err = depmod_load(&depmod);
        if (err < 0)
                goto cmdline_modules_failed;

        err = depmod_output(&depmod, out);

done:
        depmod_shutdown(&depmod);
        cfg_free(&cfg);
        return err >= 0 ? EXIT_SUCCESS : EXIT_FAILURE;

cmdline_modules_failed:
        depmod_shutdown(&depmod);
depmod_init_failed:
        if (ctx != NULL)
                kmod_unref(ctx);
cmdline_failed:
        cfg_free(&cfg);
        return EXIT_FAILURE;
}

const struct kmod_cmd kmod_cmd_compat_depmod = {
        .name = "depmod",
        .cmd = do_depmod,
        .help = "compat depmod command",
};