src/binfmt/binfmt.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2 /***
   3   This file is part of systemd.
   4
   5   Copyright 2010 Lennart Poettering
   6 ***/
   7
   8 #include <errno.h>
   9 #include <getopt.h>
  10 #include <limits.h>
  11 #include <stdbool.h>
  12 #include <stdio.h>
  13 #include <stdlib.h>
  14 #include <string.h>
  15
  16 #include "alloc-util.h"
  17 #include "conf-files.h"
  18 #include "def.h"
  19 #include "fd-util.h"
  20 #include "fileio.h"
  21 #include "log.h"
  22 #include "string-util.h"
  23 #include "strv.h"
  24 #include "util.h"
  25
  26 static const char conf_file_dirs[] = CONF_PATHS_NULSTR("binfmt.d");
  27
  28 static int delete_rule(const char *rule) {
  29         _cleanup_free_ char *x = NULL, *fn = NULL;
  30         char *e;
  31
  32         assert(rule[0]);
  33
  34         x = strdup(rule);
  35         if (!x)
  36                 return log_oom();
  37
  38         e = strchrnul(x+1, x[0]);
  39         *e = 0;
  40
  41         fn = strappend("/proc/sys/fs/binfmt_misc/", x+1);
  42         if (!fn)
  43                 return log_oom();
  44
  45         return write_string_file(fn, "-1", 0);
  46 }
  47
  48 static int apply_rule(const char *rule) {
  49         int r;
  50
  51         delete_rule(rule);
  52
  53         r = write_string_file("/proc/sys/fs/binfmt_misc/register", rule, 0);
  54         if (r < 0)
  55                 return log_error_errno(r, "Failed to add binary format: %m");
  56
  57         return 0;
  58 }
  59
  60 static int apply_file(const char *path, bool ignore_enoent) {
  61         _cleanup_fclose_ FILE *f = NULL;
  62         int r;
  63
  64         assert(path);
  65
  66         r = search_and_fopen_nulstr(path, "re", NULL, conf_file_dirs, &f);
  67         if (r < 0) {
  68                 if (ignore_enoent && r == -ENOENT)
  69                         return 0;
  70
  71                 return log_error_errno(r, "Failed to open file '%s', ignoring: %m", path);
  72         }
  73
  74         log_debug("apply: %s", path);
  75         for (;;) {
  76                 char l[LINE_MAX], *p;
  77                 int k;
  78
  79                 if (!fgets(l, sizeof(l), f)) {
  80                         if (feof(f))
  81                                 break;
  82
  83                         return log_error_errno(errno, "Failed to read file '%s', ignoring: %m", path);
  84                 }
  85
  86                 p = strstrip(l);
  87                 if (!*p)
  88                         continue;
  89                 if (strchr(COMMENTS "\n", *p))
  90                         continue;
  91
  92                 k = apply_rule(p);
  93                 if (k < 0 && r == 0)
  94                         r = k;
  95         }
  96
  97         return r;
  98 }
  99
 100 static void help(void) {
 101         printf("%s [OPTIONS...] [CONFIGURATION FILE...]\n\n"
 102                "Registers binary formats.\n\n"
 103                "  -h --help             Show this help\n"
 104                "     --version          Show package version\n"
 105                , program_invocation_short_name);
 106 }
 107
 108 static int parse_argv(int argc, char *argv[]) {
 109
 110         enum {
 111                 ARG_VERSION = 0x100,
 112         };
 113
 114         static const struct option options[] = {
 115                 { "help",      no_argument,       NULL, 'h'           },
 116                 { "version",   no_argument,       NULL, ARG_VERSION   },
 117                 {}
 118         };
 119
 120         int c;
 121
 122         assert(argc >= 0);
 123         assert(argv);
 124
 125         while ((c = getopt_long(argc, argv, "h", options, NULL)) >= 0)
 126
 127                 switch (c) {
 128
 129                 case 'h':
 130                         help();
 131                         return 0;
 132
 133                 case ARG_VERSION:
 134                         return version();
 135
 136                 case '?':
 137                         return -EINVAL;
 138
 139                 default:
 140                         assert_not_reached("Unhandled option");
 141                 }
 142
 143         return 1;
 144 }
 145
 146 int main(int argc, char *argv[]) {
 147         int r, k;
 148
 149         r = parse_argv(argc, argv);
 150         if (r <= 0)
 151                 return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
 152
 153         log_set_target(LOG_TARGET_AUTO);
 154         log_parse_environment();
 155         log_open();
 156
 157         umask(0022);
 158
 159         r = 0;
 160
 161         if (argc > optind) {
 162                 int i;
 163
 164                 for (i = optind; i < argc; i++) {
 165                         k = apply_file(argv[i], false);
 166                         if (k < 0 && r == 0)
 167                                 r = k;
 168                 }
 169         } else {
 170                 _cleanup_strv_free_ char **files = NULL;
 171                 char **f;
 172
 173                 r = conf_files_list_nulstr(&files, ".conf", NULL, 0, conf_file_dirs);
 174                 if (r < 0) {
 175                         log_error_errno(r, "Failed to enumerate binfmt.d files: %m");
 176                         goto finish;
 177                 }
 178
 179                 /* Flush out all rules */
 180                 write_string_file("/proc/sys/fs/binfmt_misc/status", "-1", 0);
 181
 182                 STRV_FOREACH(f, files) {
 183                         k = apply_file(*f, true);
 184                         if (k < 0 && r == 0)
 185                                 r = k;
 186                 }
 187         }
 188
 189 finish:
 190         return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
 191 }