testsuite/init_module.c

   1 /*
   2  * Copyright (C) 2012  ProFUSION embedded systems
   3  *
   4  * This program is free software: you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation, either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  16  */
  17
  18 #include <assert.h>
  19 #include <errno.h>
  20 #include <dirent.h>
  21 #include <fcntl.h>
  22 #include <dlfcn.h>
  23 #include <limits.h>
  24 #include <stdlib.h>
  25 #include <stdarg.h>
  26 #include <stddef.h>
  27 #include <string.h>
  28 #include <stdio.h>
  29 #include <sys/types.h>
  30 #include <sys/stat.h>
  31 #include <unistd.h>
  32
  33 /* kmod_elf_get_section() is not exported, we need the private header */
  34 #include <libkmod-private.h>
  35
  36 /* FIXME: hack, change name so we don't clash */
  37 #undef ERR
  38 #include "testsuite.h"
  39 #include "stripped-module.h"
  40
  41 struct mod {
  42         struct mod *next;
  43         int ret;
  44         int errcode;
  45         char name[];
  46 };
  47
  48 static struct mod *modules;
  49 static bool need_init = true;
  50
  51 static void parse_retcodes(struct mod *_modules, const char *s)
  52 {
  53         const char *p;
  54
  55         if (s == NULL)
  56                 return;
  57
  58         for (p = s;;) {
  59                 struct mod *mod;
  60                 const char *modname;
  61                 char *end;
  62                 size_t modnamelen;
  63                 int ret, errcode;
  64                 long l;
  65
  66                 modname = p;
  67                 if (modname == NULL || modname[0] == '\0')
  68                         break;
  69
  70                 modnamelen = strcspn(s, ":");
  71                 if (modname[modnamelen] != ':')
  72                         break;
  73
  74                 p = modname + modnamelen + 1;
  75                 if (p == NULL)
  76                         break;
  77
  78                 l = strtol(p, &end, 0);
  79                 if (end == p || *end != ':')
  80                         break;
  81                 ret = (int) l;
  82                 p = end + 1;
  83
  84                 l = strtol(p, &end, 0);
  85                 if (*end == ':')
  86                         p = end + 1;
  87                 else if (*end != '\0')
  88                         break;
  89
  90                 errcode = (int) l;
  91
  92                 mod = malloc(sizeof(*mod) + modnamelen + 1);
  93                 if (mod == NULL)
  94                         break;
  95
  96                 memcpy(mod->name, modname, modnamelen);
  97                 mod->name[modnamelen] = '\0';
  98                 mod->ret = ret;
  99                 mod->errcode = errcode;
 100                 mod->next = _modules;
 101                 _modules = mod;
 102         }
 103 }
 104
 105 static struct mod *find_module(struct mod *_modules, const char *modname)
 106 {
 107         struct mod *mod;
 108
 109         for (mod = _modules; mod != NULL; mod = mod->next) {
 110                 if (strcmp(mod->name, modname))
 111                         return mod;
 112         }
 113
 114         return NULL;
 115 }
 116
 117 static void init_retcodes(void)
 118 {
 119         const char *s;
 120
 121         if (!need_init)
 122                 return;
 123
 124         need_init = false;
 125         s = getenv(S_TC_INIT_MODULE_RETCODES);
 126         if (s == NULL) {
 127                 fprintf(stderr, "TRAP init_module(): missing export %s?\n",
 128                                                 S_TC_INIT_MODULE_RETCODES);
 129         }
 130
 131         parse_retcodes(modules, s);
 132 }
 133
 134 TS_EXPORT long init_module(void *mem, unsigned long len, const char *args);
 135
 136 /*
 137  * FIXME: change /sys/module/<modname> to fake-insert a module
 138  *
 139  * Default behavior is to exit successfully. If this is not the intended
 140  * behavior, set TESTSUITE_INIT_MODULE_RETCODES env var.
 141  */
 142 long init_module(void *mem, unsigned long len, const char *args)
 143 {
 144         const char *modname;
 145         struct kmod_elf *elf;
 146         struct mod *mod;
 147         const void *buf;
 148         uint64_t bufsize;
 149         int err;
 150
 151         init_retcodes();
 152
 153         elf = kmod_elf_new(mem, len);
 154         if (elf == NULL)
 155                 return 0;
 156
 157         err = kmod_elf_get_section(elf, ".gnu.linkonce.this_module", &buf,
 158                                                                 &bufsize);
 159         kmod_elf_unref(elf);
 160
 161         /*
 162          * We couldn't find the module's name inside the ELF file. Just exit
 163          * as if it was successful
 164          */
 165         if (err < 0)
 166                 return 0;
 167
 168         modname = (char *)buf + offsetof(struct module, name);
 169         mod = find_module(modules, modname);
 170         if (mod == NULL)
 171                 return 0;
 172
 173         errno = mod->errcode;
 174         return mod->ret;
 175 }
 176
 177 /* the test is going away anyway, but lets keep valgrind happy */
 178 void free_resources(void) __attribute__((destructor));
 179 void free_resources(void)
 180 {
 181         while (modules) {
 182                 struct mod *mod = modules->next;
 183                 free(modules);
 184                 modules = mod;
 185         }
 186 }