libsysfs/sysfs_utils.c

   1 /*
   2  * sysfs_utils.c
   3  *
   4  * System utility functions for libsysfs
   5  *
   6  * Copyright (C) IBM Corp. 2003
   7  *
   8  *  This library is free software; you can redistribute it and/or
   9  *  modify it under the terms of the GNU Lesser General Public
  10  *  License as published by the Free Software Foundation; either
  11  *  version 2.1 of the License, or (at your option) any later version.
  12  *
  13  *  This library is distributed in the hope that it will be useful,
  14  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  16  *  Lesser General Public License for more details.
  17  *
  18  *  You should have received a copy of the GNU Lesser General Public
  19  *  License along with this library; if not, write to the Free Software
  20  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  21  *
  22  */
  23 #include "sysfs/libsysfs.h"
  24 #include "sysfs.h"
  25 #ifndef __KLIBC__
  26 #include <mntent.h>
  27 #endif
  28
  29 static int sort_char(void *new_elem, void *old_elem)
  30 {
  31         return ((strncmp((char *)new_elem, (char *)old_elem,
  32                         strlen((char *)new_elem))) < 0 ? 1 : 0);
  33 }
  34
  35 /**
  36  * sysfs_remove_trailing_slash: Removes any trailing '/' in the given path
  37  * @path: Path to look for the trailing '/'
  38  * Returns 0 on success 1 on error
  39  */
  40 int sysfs_remove_trailing_slash(char *path)
  41 {
  42         char *c = NULL;
  43
  44         if (path == NULL) {
  45                 errno = EINVAL;
  46                 return 1;
  47         }
  48         c = strrchr(path, '/');
  49         if (c == NULL) {
  50                 dprintf("Invalid path %s\n", path);
  51                 errno = EINVAL;
  52                 return 1;
  53         }
  54         if (*(c+1) == '\0')
  55                 *c = '\0';
  56         return 0;
  57 }
  58
  59 /**
  60  * sysfs_get_fs_mnt_path: Gets the mount point for specified filesystem.
  61  * @fs_type: filesystem type to retrieve mount point
  62  * @mnt_path: place to put the retrieved mount path
  63  * @len: size of mnt_path
  64  * returns 0 with success and -1 with error.
  65  */
  66 static int sysfs_get_fs_mnt_path(const char *fs_type,
  67                                 char *mnt_path, size_t len)
  68 {
  69 #ifdef __KLIBC__
  70         safestrcpymax(mnt_path, "/sys", len);
  71         return 0;
  72 #else
  73         FILE *mnt;
  74         struct mntent *mntent;
  75         int ret = 0;
  76         size_t dirlen = 0;
  77
  78         /* check arg */
  79         if (fs_type == NULL || mnt_path == NULL || len == 0) {
  80                 errno = EINVAL;
  81                 return -1;
  82         }
  83
  84         if ((mnt = setmntent(SYSFS_PROC_MNTS, "r")) == NULL) {
  85                 dprintf("Error getting mount information\n");
  86                 return -1;
  87         }
  88         while (ret == 0 && dirlen == 0 && (mntent = getmntent(mnt)) != NULL) {
  89                 if (strcmp(mntent->mnt_type, fs_type) == 0) {
  90                         dirlen = strlen(mntent->mnt_dir);
  91                         if (dirlen <= (len - 1)) {
  92                                 safestrcpymax(mnt_path, mntent->mnt_dir, len);
  93                         } else {
  94                                 dprintf("Error - mount path too long\n");
  95                                 ret = -1;
  96                         }
  97                 }
  98         }
  99         endmntent(mnt);
 100         if (dirlen == 0 && ret == 0) {
 101                 dprintf("Filesystem %s not found!\n", fs_type);
 102                 errno = EINVAL;
 103                 ret = -1;
 104         }
 105         if ((sysfs_remove_trailing_slash(mnt_path)) != 0)
 106                 ret = -1;
 107
 108         return ret;
 109 #endif
 110 }
 111
 112 /*
 113  * sysfs_get_mnt_path: Gets the sysfs mount point.
 114  * @mnt_path: place to put "sysfs" mount point
 115  * @len: size of mnt_path
 116  * returns 0 with success and -1 with error.
 117  */
 118 int sysfs_get_mnt_path(char *mnt_path, size_t len)
 119 {
 120         char *sysfs_path = NULL;
 121         int ret = 0;
 122
 123         if (mnt_path == NULL || len == 0) {
 124                 errno = EINVAL;
 125                 return -1;
 126         }
 127         sysfs_path = getenv(SYSFS_PATH_ENV);
 128         if (sysfs_path != NULL) {
 129                 safestrcpymax(mnt_path, sysfs_path, len);
 130                 if ((sysfs_remove_trailing_slash(mnt_path)) != 0)
 131                         return 1;
 132         } else
 133                 ret = sysfs_get_fs_mnt_path(SYSFS_FSTYPE_NAME, mnt_path, len);
 134
 135         return ret;
 136 }
 137
 138 /**
 139  * sysfs_get_name_from_path: returns last name from a "/" delimited path
 140  * @path: path to get name from
 141  * @name: where to put name
 142  * @len: size of name
 143  */
 144 int sysfs_get_name_from_path(const char *path, char *name, size_t len)
 145 {
 146         char tmp[SYSFS_PATH_MAX];
 147         char *n = NULL;
 148
 149         if (path == NULL || name == NULL || len == 0) {
 150                 errno = EINVAL;
 151                 return -1;
 152         }
 153         memset(tmp, 0, SYSFS_PATH_MAX);
 154         safestrcpy(tmp, path);
 155         n = strrchr(tmp, '/');
 156         if (n == NULL) {
 157                 errno = EINVAL;
 158                 return -1;
 159         }
 160         if (*(n+1) == '\0') {
 161                 *n = '\0';
 162                 n = strrchr(tmp, '/');
 163                 if (n == NULL) {
 164                         errno = EINVAL;
 165                         return -1;
 166                 }
 167         }
 168         n++;
 169         safestrcpymax(name, n, len);
 170         return 0;
 171 }
 172
 173 /**
 174  * sysfs_get_link: returns link source
 175  * @path: symbolic link's path
 176  * @target: where to put name
 177  * @len: size of name
 178  */
 179 int sysfs_get_link(const char *path, char *target, size_t len)
 180 {
 181         char devdir[SYSFS_PATH_MAX];
 182         char linkpath[SYSFS_PATH_MAX];
 183         char temp_path[SYSFS_PATH_MAX];
 184         char *d = NULL, *s = NULL;
 185         int slashes = 0, count = 0;
 186
 187         if (path == NULL || target == NULL || len == 0) {
 188                 errno = EINVAL;
 189                 return -1;
 190         }
 191
 192         memset(devdir, 0, SYSFS_PATH_MAX);
 193         memset(linkpath, 0, SYSFS_PATH_MAX);
 194         memset(temp_path, 0, SYSFS_PATH_MAX);
 195         safestrcpy(devdir, path);
 196
 197         if ((readlink(path, linkpath, SYSFS_PATH_MAX)) < 0) {
 198                 return -1;
 199         }
 200         d = linkpath;
 201         /*
 202          * Three cases here:
 203          * 1. relative path => format ../..
 204          * 2. absolute path => format /abcd/efgh
 205          * 3. relative path _from_ this dir => format abcd/efgh
 206          */
 207         switch (*d) {
 208                 case '.':
 209                         /*
 210                          * handle the case where link is of type ./abcd/xxx
 211                          */
 212                         safestrcpy(temp_path, devdir);
 213                         if (*(d+1) == '/')
 214                                 d += 2;
 215                         else if (*(d+1) == '.')
 216                                 goto parse_path;
 217                         s = strrchr(temp_path, '/');
 218                         if (s != NULL) {
 219                                 *(s+1) = '\0';
 220                                 safestrcat(temp_path, d);
 221                         } else {
 222                                 safestrcpy(temp_path, d);
 223                         }
 224                         safestrcpymax(target, temp_path, len);
 225                         break;
 226                         /*
 227                          * relative path
 228                          * getting rid of leading "../.."
 229                          */
 230 parse_path:
 231                         while (*d == '/' || *d == '.') {
 232                                 if (*d == '/')
 233                                         slashes++;
 234                                 d++;
 235                         }
 236                         d--;
 237                         s = &devdir[strlen(devdir)-1];
 238                         while (s != NULL && count != (slashes+1)) {
 239                                 s--;
 240                                 if (*s == '/')
 241                                         count++;
 242                         }
 243                         safestrcpymax(s, d, (SYSFS_PATH_MAX-strlen(devdir)));
 244                         safestrcpymax(target, devdir, len);
 245                         break;
 246                 case '/':
 247                         /* absolute path - copy as is */
 248                         safestrcpymax(target, linkpath, len);
 249                         break;
 250                 default:
 251                         /* relative path from this directory */
 252                         safestrcpy(temp_path, devdir);
 253                         s = strrchr(temp_path, '/');
 254                         if (s != NULL) {
 255                                 *(s+1) = '\0';
 256                                 safestrcat(temp_path, linkpath);
 257                         } else {
 258                                 safestrcpy(temp_path, linkpath);
 259                         }
 260                         safestrcpymax(target, temp_path, len);
 261         }
 262         return 0;
 263 }
 264
 265 /**
 266  * sysfs_del_name: free function for sysfs_open_subsystem_list
 267  * @name: memory area to be freed
 268  */
 269 static void sysfs_del_name(void *name)
 270 {
 271         free(name);
 272 }
 273
 274
 275 /**
 276  * sysfs_close_list: generic list free routine
 277  * @list: dlist to free
 278  * Returns nothing
 279  */
 280 void sysfs_close_list(struct dlist *list)
 281 {
 282         if (list != NULL)
 283                 dlist_destroy(list);
 284 }
 285
 286 /**
 287  * sysfs_open_subsystem_list: gets a list of all supported "name" subsystem
 288  *      details from the system
 289  * @name: name of the subsystem, eg., "bus", "class", "devices"
 290  * Returns a dlist of supported names or NULL if subsystem not supported
 291  */
 292 struct dlist *sysfs_open_subsystem_list(char *name)
 293 {
 294         char sysfs_path[SYSFS_PATH_MAX], *subsys_name = NULL;
 295         char *c = NULL;
 296         struct sysfs_directory *dir = NULL, *cur = NULL;
 297         struct dlist *list = NULL;
 298
 299         if (name == NULL)
 300                 return NULL;
 301
 302         if (sysfs_get_mnt_path(sysfs_path, SYSFS_PATH_MAX) != 0) {
 303                 dprintf("Error getting sysfs mount point\n");
 304                 return NULL;
 305         }
 306
 307         safestrcat(sysfs_path, "/");
 308         safestrcat(sysfs_path, name);
 309         dir = sysfs_open_directory(sysfs_path);
 310         if (dir == NULL) {
 311                 dprintf("Error opening sysfs_directory at %s\n", sysfs_path);
 312                 return NULL;
 313         }
 314
 315         if ((sysfs_read_dir_subdirs(dir)) != 0) {
 316                 dprintf("Error reading sysfs_directory at %s\n", sysfs_path);
 317                 sysfs_close_directory(dir);
 318                 return NULL;
 319         }
 320
 321         if (dir->subdirs != NULL) {
 322                 list = dlist_new_with_delete(SYSFS_NAME_LEN,
 323                                 sysfs_del_name);
 324                 if (list == NULL) {
 325                         dprintf("Error creating list\n");
 326                         sysfs_close_directory(dir);
 327                         return NULL;
 328                 }
 329
 330                 dlist_for_each_data(dir->subdirs, cur,
 331                                 struct sysfs_directory) {
 332                         subsys_name = (char *)calloc(1, SYSFS_NAME_LEN);
 333                         safestrcpymax(subsys_name, cur->name, SYSFS_NAME_LEN);
 334                         dlist_unshift_sorted(list, subsys_name, sort_char);
 335                 }
 336         }
 337         sysfs_close_directory(dir);
 338         /*
 339          * We are now considering "block" as a "class". Hence, if the subsys
 340          * name requested here is "class", verify if "block" is supported on
 341          * this system and return the same.
 342          */
 343         if (strcmp(name, SYSFS_CLASS_NAME) == 0) {
 344                 c = strstr(sysfs_path, SYSFS_CLASS_NAME);
 345                 if (c == NULL)
 346                         goto out;
 347                 *c = '\0';
 348                 safestrcpymax(c, SYSFS_BLOCK_NAME,
 349                                 sizeof(sysfs_path) - strlen(sysfs_path));
 350                 if ((sysfs_path_is_dir(sysfs_path)) == 0) {
 351                         subsys_name = (char *)calloc(1, SYSFS_NAME_LEN);
 352                         safestrcpymax(subsys_name, SYSFS_BLOCK_NAME,
 353                                         SYSFS_NAME_LEN);
 354                         dlist_unshift_sorted(list, subsys_name, sort_char);
 355                 }
 356         }
 357 out:
 358         return list;
 359 }
 360
 361
 362 /**
 363  * sysfs_open_bus_devices_list: gets a list of all devices on "name" bus
 364  * @name: name of the subsystem, eg., "pci", "scsi", "usb"
 365  * Returns a dlist of supported names or NULL if subsystem not supported
 366  */
 367 struct dlist *sysfs_open_bus_devices_list(char *name)
 368 {
 369         char sysfs_path[SYSFS_PATH_MAX], *device_name = NULL;
 370         struct sysfs_directory *dir = NULL;
 371         struct sysfs_link *cur = NULL;
 372         struct dlist *list = NULL;
 373
 374         if (name == NULL)
 375                 return NULL;
 376
 377         if (sysfs_get_mnt_path(sysfs_path, SYSFS_PATH_MAX) != 0) {
 378                 dprintf("Error getting sysfs mount point\n");
 379                 return NULL;
 380         }
 381
 382         safestrcat(sysfs_path, "/");
 383         safestrcat(sysfs_path, SYSFS_BUS_NAME);
 384         safestrcat(sysfs_path, "/");
 385         safestrcat(sysfs_path, name);
 386         safestrcat(sysfs_path, "/");
 387         safestrcat(sysfs_path, SYSFS_DEVICES_NAME);
 388         dir = sysfs_open_directory(sysfs_path);
 389         if (dir == NULL) {
 390                 dprintf("Error opening sysfs_directory at %s\n", sysfs_path);
 391                 return NULL;
 392         }
 393
 394         if ((sysfs_read_dir_links(dir)) != 0) {
 395                 dprintf("Error reading sysfs_directory at %s\n", sysfs_path);
 396                 sysfs_close_directory(dir);
 397                 return NULL;
 398         }
 399
 400         if (dir->links != NULL) {
 401                 list = dlist_new_with_delete(SYSFS_NAME_LEN,
 402                                 sysfs_del_name);
 403                 if (list == NULL) {
 404                         dprintf("Error creating list\n");
 405                         sysfs_close_directory(dir);
 406                         return NULL;
 407                 }
 408
 409                 dlist_for_each_data(dir->links, cur,
 410                                 struct sysfs_link) {
 411                         device_name = (char *)calloc(1, SYSFS_NAME_LEN);
 412                         safestrcpymax(device_name, cur->name, SYSFS_NAME_LEN);
 413                         dlist_unshift_sorted(list, device_name, sort_char);
 414                 }
 415         }
 416         sysfs_close_directory(dir);
 417         return list;
 418 }
 419
 420 /**
 421  * sysfs_path_is_dir: Check if the path supplied points to a directory
 422  * @path: path to validate
 423  * Returns 0 if path points to dir, 1 otherwise
 424  */
 425 int sysfs_path_is_dir(const char *path)
 426 {
 427         struct stat astats;
 428
 429         if (path == NULL) {
 430                 errno = EINVAL;
 431                 return 1;
 432         }
 433         if ((lstat(path, &astats)) != 0) {
 434                 dprintf("stat() failed\n");
 435                 return 1;
 436         }
 437         if (S_ISDIR(astats.st_mode))
 438                 return 0;
 439
 440         return 1;
 441 }
 442
 443 /**
 444  * sysfs_path_is_link: Check if the path supplied points to a link
 445  * @path: path to validate
 446  * Returns 0 if path points to link, 1 otherwise
 447  */
 448 int sysfs_path_is_link(const char *path)
 449 {
 450         struct stat astats;
 451
 452         if (path == NULL) {
 453                 errno = EINVAL;
 454                 return 1;
 455         }
 456         if ((lstat(path, &astats)) != 0) {
 457                 dprintf("stat() failed\n");
 458                 return 1;
 459         }
 460         if (S_ISLNK(astats.st_mode))
 461                 return 0;
 462
 463         return 1;
 464 }
 465
 466 /**
 467  * sysfs_path_is_file: Check if the path supplied points to a file
 468  * @path: path to validate
 469  * Returns 0 if path points to file, 1 otherwise
 470  */
 471 int sysfs_path_is_file(const char *path)
 472 {
 473         struct stat astats;
 474
 475         if (path == NULL) {
 476                 errno = EINVAL;
 477                 return 1;
 478         }
 479         if ((lstat(path, &astats)) != 0) {
 480                 dprintf("stat() failed\n");
 481                 return 1;
 482         }
 483         if (S_ISREG(astats.st_mode))
 484                 return 0;
 485
 486         return 1;
 487 }