libkmod/libkmod-file.c

   1 /*
   2  * libkmod - interface to kernel module operations
   3  *
   4  * Copyright (C) 2011-2012  ProFUSION embedded systems
   5  *
   6  * This library is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2.1 of the License, or (at your option) any later version.
  10  *
  11  * This library is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with this library; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  19  */
  20
  21 #include <stdbool.h>
  22 #include <stdio.h>
  23 #include <stdlib.h>
  24 #include <errno.h>
  25 #include <string.h>
  26 #include <sys/types.h>
  27 #include <sys/stat.h>
  28 #include <sys/mman.h>
  29 #include <unistd.h>
  30
  31 #include "libkmod.h"
  32 #include "libkmod-private.h"
  33
  34 #ifdef ENABLE_XZ
  35 #include <lzma.h>
  36 #endif
  37 #ifdef ENABLE_ZLIB
  38 #include <zlib.h>
  39 #endif
  40
  41 struct kmod_file;
  42 struct file_ops {
  43         int (*load)(struct kmod_file *file);
  44         void (*unload)(struct kmod_file *file);
  45 };
  46
  47 struct kmod_file {
  48 #ifdef ENABLE_XZ
  49         bool xz_used;
  50 #endif
  51 #ifdef ENABLE_ZLIB
  52         gzFile gzf;
  53 #endif
  54         int fd;
  55         off_t size;
  56         void *memory;
  57         const struct file_ops *ops;
  58         const struct kmod_ctx *ctx;
  59         struct kmod_elf *elf;
  60 };
  61
  62 #ifdef ENABLE_XZ
  63 static void xz_uncompress_belch(struct kmod_file *file, lzma_ret ret)
  64 {
  65         switch (ret) {
  66         case LZMA_MEM_ERROR:
  67                 ERR(file->ctx, "xz: %s\n", strerror(ENOMEM));
  68                 break;
  69         case LZMA_FORMAT_ERROR:
  70                 ERR(file->ctx, "xz: File format not recognized\n");
  71                 break;
  72         case LZMA_OPTIONS_ERROR:
  73                 ERR(file->ctx, "xz: Unsupported compression options\n");
  74                 break;
  75         case LZMA_DATA_ERROR:
  76                 ERR(file->ctx, "xz: File is corrupt\n");
  77                 break;
  78         case LZMA_BUF_ERROR:
  79                 ERR(file->ctx, "xz: Unexpected end of input\n");
  80                 break;
  81         default:
  82                 ERR(file->ctx, "xz: Internal error (bug)\n");
  83                 break;
  84         }
  85 }
  86
  87 static int xz_uncompress(lzma_stream *strm, struct kmod_file *file)
  88 {
  89         uint8_t in_buf[BUFSIZ], out_buf[BUFSIZ];
  90         lzma_action action = LZMA_RUN;
  91         lzma_ret ret;
  92         void *p = NULL;
  93         size_t total = 0;
  94
  95         strm->avail_in  = 0;
  96         strm->next_out  = out_buf;
  97         strm->avail_out = sizeof(out_buf);
  98
  99         while (true) {
 100                 if (strm->avail_in == 0) {
 101                         ssize_t rdret = read(file->fd, in_buf, sizeof(in_buf));
 102                         if (rdret < 0) {
 103                                 ret = -errno;
 104                                 goto out;
 105                         }
 106                         strm->next_in  = in_buf;
 107                         strm->avail_in = rdret;
 108                         if (rdret == 0)
 109                                 action = LZMA_FINISH;
 110                 }
 111                 ret = lzma_code(strm, action);
 112                 if (strm->avail_out == 0 || ret != LZMA_OK) {
 113                         size_t write_size = BUFSIZ - strm->avail_out;
 114                         char *tmp = realloc(p, total + write_size);
 115                         if (tmp == NULL) {
 116                                 ret = -errno;
 117                                 goto out;
 118                         }
 119                         memcpy(tmp + total, out_buf, write_size);
 120                         total += write_size;
 121                         p = tmp;
 122                         strm->next_out = out_buf;
 123                         strm->avail_out = BUFSIZ;
 124                 }
 125                 if (ret == LZMA_STREAM_END)
 126                         break;
 127                 if (ret != LZMA_OK) {
 128                         xz_uncompress_belch(file, ret);
 129                         ret = -EINVAL;
 130                         goto out;
 131                 }
 132         }
 133         file->xz_used = true;
 134         file->memory = p;
 135         file->size = total;
 136         return 0;
 137  out:
 138         free(p);
 139         return ret;
 140 }
 141
 142 static int load_xz(struct kmod_file *file)
 143 {
 144         lzma_stream strm = LZMA_STREAM_INIT;
 145         lzma_ret lzret;
 146         int ret;
 147
 148         lzret = lzma_stream_decoder(&strm, UINT64_MAX, LZMA_CONCATENATED);
 149         if (lzret == LZMA_MEM_ERROR) {
 150                 ERR(file->ctx, "xz: %s\n", strerror(ENOMEM));
 151                 return -ENOMEM;
 152         } else if (lzret != LZMA_OK) {
 153                 ERR(file->ctx, "xz: Internal error (bug)\n");
 154                 return -EINVAL;
 155         }
 156         ret = xz_uncompress(&strm, file);
 157         lzma_end(&strm);
 158         return ret;
 159 }
 160
 161 static void unload_xz(struct kmod_file *file)
 162 {
 163         if (!file->xz_used)
 164                 return;
 165         free(file->memory);
 166 }
 167
 168 static const char magic_xz[] = {0xfd, '7', 'z', 'X', 'Z', 0};
 169 #endif
 170
 171 #ifdef ENABLE_ZLIB
 172 #define READ_STEP (4 * 1024 * 1024)
 173 static int load_zlib(struct kmod_file *file)
 174 {
 175         int err = 0;
 176         off_t did = 0, total = 0;
 177         unsigned char *p = NULL;
 178
 179         errno = 0;
 180         file->gzf = gzdopen(file->fd, "rb");
 181         if (file->gzf == NULL) {
 182                 return -errno;
 183         }
 184         file->fd = -1; /* now owned by gzf due gzdopen() */
 185
 186         for (;;) {
 187                 int r;
 188
 189                 if (did == total) {
 190                         void *tmp = realloc(p, total + READ_STEP);
 191                         if (tmp == NULL) {
 192                                 err = -errno;
 193                                 goto error;
 194                         }
 195                         total += READ_STEP;
 196                         p = tmp;
 197                 }
 198
 199                 r = gzread(file->gzf, p + did, total - did);
 200                 if (r == 0)
 201                         break;
 202                 else if (r < 0) {
 203                         int gzerr;
 204                         const char *gz_errmsg = gzerror(file->gzf, &gzerr);
 205
 206                         ERR(file->ctx, "gzip: %s\n", gz_errmsg);
 207
 208                         /* gzip might not set errno here */
 209                         err = gzerr == Z_ERRNO ? -errno : -EINVAL;
 210                         goto error;
 211                 }
 212                 did += r;
 213         }
 214
 215         file->memory = p;
 216         file->size = did;
 217         return 0;
 218 error:
 219         free(p);
 220         gzclose(file->gzf);
 221         return err;
 222 }
 223
 224 static void unload_zlib(struct kmod_file *file)
 225 {
 226         if (file->gzf == NULL)
 227                 return;
 228         free(file->memory);
 229         gzclose(file->gzf); /* closes file->fd */
 230 }
 231
 232 static const char magic_zlib[] = {0x1f, 0x8b};
 233 #endif
 234
 235 static const struct comp_type {
 236         size_t magic_size;
 237         const char *magic_bytes;
 238         const struct file_ops ops;
 239 } comp_types[] = {
 240 #ifdef ENABLE_XZ
 241         {sizeof(magic_xz), magic_xz, {load_xz, unload_xz}},
 242 #endif
 243 #ifdef ENABLE_ZLIB
 244         {sizeof(magic_zlib), magic_zlib, {load_zlib, unload_zlib}},
 245 #endif
 246         {0, NULL, {NULL, NULL}}
 247 };
 248
 249 static int load_reg(struct kmod_file *file)
 250 {
 251         struct stat st;
 252
 253         if (fstat(file->fd, &st) < 0)
 254                 return -errno;
 255
 256         file->size = st.st_size;
 257         file->memory = mmap(0, file->size, PROT_READ, MAP_PRIVATE, file->fd, 0);
 258         if (file->memory == MAP_FAILED)
 259                 return -errno;
 260         return 0;
 261 }
 262
 263 static void unload_reg(struct kmod_file *file)
 264 {
 265         munmap(file->memory, file->size);
 266 }
 267
 268 static const struct file_ops reg_ops = {
 269         load_reg, unload_reg
 270 };
 271
 272 struct kmod_elf *kmod_file_get_elf(struct kmod_file *file)
 273 {
 274         if (file->elf)
 275                 return file->elf;
 276
 277         file->elf = kmod_elf_new(file->memory, file->size);
 278         return file->elf;
 279 }
 280
 281 struct kmod_file *kmod_file_open(const struct kmod_ctx *ctx,
 282                                                 const char *filename)
 283 {
 284         struct kmod_file *file = calloc(1, sizeof(struct kmod_file));
 285         const struct comp_type *itr;
 286         size_t magic_size_max = 0;
 287         int err;
 288
 289         if (file == NULL)
 290                 return NULL;
 291
 292         file->fd = open(filename, O_RDONLY|O_CLOEXEC);
 293         if (file->fd < 0) {
 294                 err = -errno;
 295                 goto error;
 296         }
 297
 298         for (itr = comp_types; itr->ops.load != NULL; itr++) {
 299                 if (magic_size_max < itr->magic_size)
 300                         magic_size_max = itr->magic_size;
 301         }
 302
 303         if (magic_size_max > 0) {
 304                 char *buf = alloca(magic_size_max + 1);
 305                 ssize_t sz;
 306
 307                 if (buf == NULL) {
 308                         err = -errno;
 309                         goto error;
 310                 }
 311                 sz = read_str_safe(file->fd, buf, magic_size_max + 1);
 312                 lseek(file->fd, 0, SEEK_SET);
 313                 if (sz != (ssize_t)magic_size_max) {
 314                         if (sz < 0)
 315                                 err = sz;
 316                         else
 317                                 err = -EINVAL;
 318                         goto error;
 319                 }
 320
 321                 for (itr = comp_types; itr->ops.load != NULL; itr++) {
 322                         if (memcmp(buf, itr->magic_bytes, itr->magic_size) == 0)
 323                                 break;
 324                 }
 325                 if (itr->ops.load != NULL)
 326                         file->ops = &itr->ops;
 327         }
 328
 329         if (file->ops == NULL)
 330                 file->ops = &reg_ops;
 331
 332         err = file->ops->load(file);
 333         file->ctx = ctx;
 334 error:
 335         if (err < 0) {
 336                 if (file->fd >= 0)
 337                         close(file->fd);
 338                 free(file);
 339                 errno = -err;
 340                 return NULL;
 341         }
 342
 343         return file;
 344 }
 345
 346 void *kmod_file_get_contents(const struct kmod_file *file)
 347 {
 348         return file->memory;
 349 }
 350
 351 off_t kmod_file_get_size(const struct kmod_file *file)
 352 {
 353         return file->size;
 354 }
 355
 356 void kmod_file_unref(struct kmod_file *file)
 357 {
 358         if (file->elf)
 359                 kmod_elf_unref(file->elf);
 360
 361         file->ops->unload(file);
 362         if (file->fd >= 0)
 363                 close(file->fd);
 364         free(file);
 365 }