release/src/router/busybox/modutils/modutils.c

   1 /*
   2  * Common modutils related functions for busybox
   3  *
   4  * Copyright (C) 2008 by Timo Teras <timo.teras@iki.fi>
   5  *
   6  * Licensed under GPLv2 or later, see file LICENSE in this source tree.
   7  */
   8 #include "modutils.h"
   9
  10 #ifdef __UCLIBC__
  11 extern int init_module(void *module, unsigned long len, const char *options);
  12 extern int delete_module(const char *module, unsigned int flags);
  13 #else
  14 # include <sys/syscall.h>
  15 # define init_module(mod, len, opts) syscall(__NR_init_module, mod, len, opts)
  16 # define delete_module(mod, flags) syscall(__NR_delete_module, mod, flags)
  17 #endif
  18
  19 void FAST_FUNC replace(char *s, char what, char with)
  20 {
  21         while (*s) {
  22                 if (what == *s)
  23                         *s = with;
  24                 ++s;
  25         }
  26 }
  27
  28 char* FAST_FUNC replace_underscores(char *s)
  29 {
  30         replace(s, '-', '_');
  31         return s;
  32 }
  33
  34 int FAST_FUNC string_to_llist(char *string, llist_t **llist, const char *delim)
  35 {
  36         char *tok;
  37         int len = 0;
  38
  39         while ((tok = strsep(&string, delim)) != NULL) {
  40                 if (tok[0] == '\0')
  41                         continue;
  42                 llist_add_to_end(llist, xstrdup(tok));
  43                 len += strlen(tok);
  44         }
  45         return len;
  46 }
  47
  48 char* FAST_FUNC filename2modname(const char *filename, char *modname)
  49 {
  50         int i;
  51         char *from;
  52
  53         if (filename == NULL)
  54                 return NULL;
  55         if (modname == NULL)
  56                 modname = xmalloc(MODULE_NAME_LEN);
  57         from = bb_get_last_path_component_nostrip(filename);
  58         for (i = 0; i < (MODULE_NAME_LEN-1) && from[i] != '\0' && from[i] != '.'; i++)
  59                 modname[i] = (from[i] == '-') ? '_' : from[i];
  60         modname[i] = '\0';
  61
  62         return modname;
  63 }
  64
  65 char* FAST_FUNC parse_cmdline_module_options(char **argv, int quote_spaces)
  66 {
  67         char *options;
  68         int optlen;
  69
  70         options = xzalloc(1);
  71         optlen = 0;
  72         while (*++argv) {
  73                 const char *fmt;
  74                 const char *var;
  75                 const char *val;
  76
  77                 var = *argv;
  78                 options = xrealloc(options, optlen + 2 + strlen(var) + 2);
  79                 fmt = "%.*s%s ";
  80                 val = strchrnul(var, '=');
  81                 if (quote_spaces) {
  82                         /*
  83                          * modprobe (module-init-tools version 3.11.1) compat:
  84                          * quote only value:
  85                          * var="val with spaces", not "var=val with spaces"
  86                          * (note: var *name* is not checked for spaces!)
  87                          */
  88                         if (*val) { /* has var=val format. skip '=' */
  89                                 val++;
  90                                 if (strchr(val, ' '))
  91                                         fmt = "%.*s\"%s\" ";
  92                         }
  93                 }
  94                 optlen += sprintf(options + optlen, fmt, (int)(val - var), var, val);
  95         }
  96         /* Remove trailing space. Disabled */
  97         /* if (optlen != 0) options[optlen-1] = '\0'; */
  98         return options;
  99 }
 100
 101 #if ENABLE_FEATURE_INSMOD_TRY_MMAP
 102 void* FAST_FUNC try_to_mmap_module(const char *filename, size_t *image_size_p)
 103 {
 104         /* We have user reports of failure to load 3MB module
 105          * on a 16MB RAM machine. Apparently even a transient
 106          * memory spike to 6MB during module load
 107          * is too big for that system. */
 108         void *image;
 109         struct stat st;
 110         int fd;
 111
 112         fd = xopen(filename, O_RDONLY);
 113         fstat(fd, &st);
 114         image = NULL;
 115         /* st.st_size is off_t, we can't just pass it to mmap */
 116         if (st.st_size <= *image_size_p) {
 117                 size_t image_size = st.st_size;
 118                 image = mmap(NULL, image_size, PROT_READ, MAP_PRIVATE, fd, 0);
 119                 if (image == MAP_FAILED) {
 120                         image = NULL;
 121                 } else if (*(uint32_t*)image != SWAP_BE32(0x7f454C46)) {
 122                         /* No ELF signature. Compressed module? */
 123                         munmap(image, image_size);
 124                         image = NULL;
 125                 } else {
 126                         /* Success. Report the size */
 127                         *image_size_p = image_size;
 128                 }
 129         }
 130         close(fd);
 131         return image;
 132 }
 133 #endif
 134
 135 /* Return:
 136  * 0 on success,
 137  * -errno on open/read error,
 138  * errno on init_module() error
 139  */
 140 int FAST_FUNC bb_init_module(const char *filename, const char *options)
 141 {
 142         size_t image_size;
 143         char *image;
 144         int rc;
 145         bool mmaped;
 146
 147         if (!options)
 148                 options = "";
 149
 150 //TODO: audit bb_init_module_24 to match error code convention
 151 #if ENABLE_FEATURE_2_4_MODULES
 152         if (get_linux_version_code() < KERNEL_VERSION(2,6,0))
 153                 return bb_init_module_24(filename, options);
 154 #endif
 155
 156         image_size = INT_MAX - 4095;
 157         mmaped = 0;
 158         image = try_to_mmap_module(filename, &image_size);
 159         if (image) {
 160                 mmaped = 1;
 161         } else {
 162                 errno = ENOMEM; /* may be changed by e.g. open errors below */
 163                 image = xmalloc_open_zipped_read_close(filename, &image_size);
 164                 if (!image)
 165                         return -errno;
 166         }
 167
 168         errno = 0;
 169         init_module(image, image_size, options);
 170         rc = errno;
 171         if (mmaped)
 172                 munmap(image, image_size);
 173         else
 174                 free(image);
 175         return rc;
 176 }
 177
 178 int FAST_FUNC bb_delete_module(const char *module, unsigned int flags)
 179 {
 180         errno = 0;
 181         delete_module(module, flags);
 182         return errno;
 183 }
 184
 185 const char* FAST_FUNC moderror(int err)
 186 {
 187         switch (err) {
 188         case -1: /* btw: it's -EPERM */
 189                 return "no such module";
 190         case ENOEXEC:
 191                 return "invalid module format";
 192         case ENOENT:
 193                 return "unknown symbol in module, or unknown parameter";
 194         case ESRCH:
 195                 return "module has wrong symbol version";
 196         case ENOSYS:
 197                 return "kernel does not support requested operation";
 198         }
 199         if (err < 0) /* should always be */
 200                 err = -err;
 201         return strerror(err);
 202 }