udev/udev-util.c

   1 /*
   2  * Copyright (C) 2004-2008 Kay Sievers <kay.sievers@vrfy.org>
   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 <stdlib.h>
  19 #include <stdio.h>
  20 #include <stddef.h>
  21 #include <unistd.h>
  22 #include <string.h>
  23 #include <fcntl.h>
  24 #include <errno.h>
  25 #include <ctype.h>
  26 #include <pwd.h>
  27 #include <grp.h>
  28 #include <sys/wait.h>
  29
  30 #include "udev.h"
  31
  32 int util_create_path(struct udev *udev, const char *path)
  33 {
  34         char p[UTIL_PATH_SIZE];
  35         char *pos;
  36         struct stat stats;
  37         int ret;
  38
  39         util_strscpy(p, sizeof(p), path);
  40         pos = strrchr(p, '/');
  41         if (pos == p || pos == NULL)
  42                 return 0;
  43
  44         while (pos[-1] == '/')
  45                 pos--;
  46         pos[0] = '\0';
  47
  48         dbg(udev, "stat '%s'\n", p);
  49         if (stat(p, &stats) == 0 && (stats.st_mode & S_IFMT) == S_IFDIR)
  50                 return 0;
  51
  52         if (util_create_path(udev, p) != 0)
  53                 return -1;
  54
  55         dbg(udev, "mkdir '%s'\n", p);
  56         udev_selinux_setfscreatecon(udev, p, S_IFDIR|0755);
  57         ret = mkdir(p, 0755);
  58         udev_selinux_resetfscreatecon(udev);
  59         if (ret == 0)
  60                 return 0;
  61
  62         if (errno == EEXIST)
  63                 if (stat(p, &stats) == 0 && (stats.st_mode & S_IFMT) == S_IFDIR)
  64                         return 0;
  65         return -1;
  66 }
  67
  68 int util_delete_path(struct udev *udev, const char *path)
  69 {
  70         char p[UTIL_PATH_SIZE];
  71         char *pos;
  72         int retval;
  73
  74         strcpy (p, path);
  75         pos = strrchr(p, '/');
  76         if (pos == p || pos == NULL)
  77                 return 0;
  78
  79         while (1) {
  80                 *pos = '\0';
  81                 pos = strrchr(p, '/');
  82
  83                 /* don't remove the last one */
  84                 if ((pos == p) || (pos == NULL))
  85                         break;
  86
  87                 /* remove if empty */
  88                 retval = rmdir(p);
  89                 if (errno == ENOENT)
  90                         retval = 0;
  91                 if (retval) {
  92                         if (errno == ENOTEMPTY)
  93                                 return 0;
  94                         err(udev, "rmdir(%s) failed: %m\n", p);
  95                         break;
  96                 }
  97                 dbg(udev, "removed '%s'\n", p);
  98         }
  99         return 0;
 100 }
 101
 102 /* Reset permissions on the device node, before unlinking it to make sure,
 103  * that permisions of possible hard links will be removed too.
 104  */
 105 int util_unlink_secure(struct udev *udev, const char *filename)
 106 {
 107         int retval;
 108
 109         retval = chown(filename, 0, 0);
 110         if (retval)
 111                 err(udev, "chown(%s, 0, 0) failed: %m\n", filename);
 112
 113         retval = chmod(filename, 0000);
 114         if (retval)
 115                 err(udev, "chmod(%s, 0000) failed: %m\n", filename);
 116
 117         retval = unlink(filename);
 118         if (errno == ENOENT)
 119                 retval = 0;
 120
 121         if (retval)
 122                 err(udev, "unlink(%s) failed: %m\n", filename);
 123
 124         return retval;
 125 }
 126
 127 uid_t util_lookup_user(struct udev *udev, const char *user)
 128 {
 129         char *endptr;
 130         int buflen = sysconf(_SC_GETPW_R_SIZE_MAX);
 131         char buf[buflen];
 132         struct passwd pwbuf;
 133         struct passwd *pw;
 134         uid_t uid;
 135
 136         if (strcmp(user, "root") == 0)
 137                 return 0;
 138         uid = strtoul(user, &endptr, 10);
 139         if (endptr[0] == '\0')
 140                 return uid;
 141
 142         errno = 0;
 143         getpwnam_r(user, &pwbuf, buf, buflen, &pw);
 144         if (pw != NULL)
 145                 return pw->pw_uid;
 146         if (errno == 0 || errno == ENOENT || errno == ESRCH)
 147                 err(udev, "specified user '%s' unknown\n", user);
 148         else
 149                 err(udev, "error resolving user '%s': %m\n", user);
 150         return 0;
 151 }
 152
 153 gid_t util_lookup_group(struct udev *udev, const char *group)
 154 {
 155         char *endptr;
 156         int buflen = sysconf(_SC_GETGR_R_SIZE_MAX);
 157         char buf[buflen];
 158         struct group grbuf;
 159         struct group *gr;
 160         gid_t gid = 0;
 161
 162         if (strcmp(group, "root") == 0)
 163                 return 0;
 164         gid = strtoul(group, &endptr, 10);
 165         if (endptr[0] == '\0')
 166                 return gid;
 167
 168         errno = 0;
 169         getgrnam_r(group, &grbuf, buf, buflen, &gr);
 170         if (gr != NULL)
 171                 return gr->gr_gid;
 172         if (errno == 0 || errno == ENOENT || errno == ESRCH)
 173                 err(udev, "specified group '%s' unknown\n", group);
 174         else
 175                 err(udev, "error resolving group '%s': %m\n", group);
 176         return 0;
 177 }
 178
 179 /* handle "[<SUBSYSTEM>/<KERNEL>]<attribute>" format */
 180 int util_resolve_subsys_kernel(struct udev *udev, const char *string,
 181                                char *result, size_t maxsize, int read_value)
 182 {
 183         char temp[UTIL_PATH_SIZE];
 184         char *subsys;
 185         char *sysname;
 186         struct udev_device *dev;
 187         char *attr;
 188
 189         if (string[0] != '[')
 190                 return -1;
 191
 192         util_strscpy(temp, sizeof(temp), string);
 193
 194         subsys = &temp[1];
 195
 196         sysname = strchr(subsys, '/');
 197         if (sysname == NULL)
 198                 return -1;
 199         sysname[0] = '\0';
 200         sysname = &sysname[1];
 201
 202         attr = strchr(sysname, ']');
 203         if (attr == NULL)
 204                 return -1;
 205         attr[0] = '\0';
 206         attr = &attr[1];
 207         if (attr[0] == '/')
 208                 attr = &attr[1];
 209         if (attr[0] == '\0')
 210                 attr = NULL;
 211
 212         if (read_value && attr == NULL)
 213                 return -1;
 214
 215         dev = udev_device_new_from_subsystem_sysname(udev, subsys, sysname);
 216         if (dev == NULL)
 217                 return -1;
 218
 219         if (read_value) {
 220                 const char *val;
 221
 222                 val = udev_device_get_sysattr_value(dev, attr);
 223                 if (val != NULL)
 224                         util_strscpy(result, maxsize, val);
 225                 else
 226                         result[0] = '\0';
 227                 info(udev, "value '[%s/%s]%s' is '%s'\n", subsys, sysname, attr, result);
 228         } else {
 229                 size_t l;
 230                 char *s;
 231
 232                 s = result;
 233                 l = util_strpcpyl(&s, maxsize, udev_device_get_syspath(dev), NULL);
 234                 if (attr != NULL)
 235                         util_strpcpyl(&s, l, "/", attr, NULL);
 236                 info(udev, "path '[%s/%s]%s' is '%s'\n", subsys, sysname, attr, result);
 237         }
 238         udev_device_unref(dev);
 239         return 0;
 240 }
 241
 242 int util_run_program(struct udev *udev, const char *command, char **envp,
 243                      char *result, size_t ressize, size_t *reslen)
 244 {
 245         int status;
 246         int outpipe[2] = {-1, -1};
 247         int errpipe[2] = {-1, -1};
 248         pid_t pid;
 249         char arg[UTIL_PATH_SIZE];
 250         char program[UTIL_PATH_SIZE];
 251         char *argv[(sizeof(arg) / 2) + 1];
 252         int devnull;
 253         int i;
 254         int err = 0;
 255
 256         /* build argv from command */
 257         util_strscpy(arg, sizeof(arg), command);
 258         i = 0;
 259         if (strchr(arg, ' ') != NULL) {
 260                 char *pos = arg;
 261
 262                 while (pos != NULL && pos[0] != '\0') {
 263                         if (pos[0] == '\'') {
 264                                 /* do not separate quotes */
 265                                 pos++;
 266                                 argv[i] = strsep(&pos, "\'");
 267                                 while (pos != NULL && pos[0] == ' ')
 268                                         pos++;
 269                         } else {
 270                                 argv[i] = strsep(&pos, " ");
 271                         }
 272                         dbg(udev, "arg[%i] '%s'\n", i, argv[i]);
 273                         i++;
 274                 }
 275                 argv[i] = NULL;
 276         } else {
 277                 argv[0] = arg;
 278                 argv[1] = NULL;
 279         }
 280         info(udev, "'%s'\n", command);
 281
 282         /* prepare pipes from child to parent */
 283         if (result != NULL || udev_get_log_priority(udev) >= LOG_INFO) {
 284                 if (pipe(outpipe) != 0) {
 285                         err(udev, "pipe failed: %m\n");
 286                         return -1;
 287                 }
 288         }
 289         if (udev_get_log_priority(udev) >= LOG_INFO) {
 290                 if (pipe(errpipe) != 0) {
 291                         err(udev, "pipe failed: %m\n");
 292                         return -1;
 293                 }
 294         }
 295
 296         /* allow programs in /lib/udev/ to be called without the path */
 297         if (argv[0][0] != '/') {
 298                 util_strscpyl(program, sizeof(program), UDEV_PREFIX "/lib/udev/", argv[0], NULL);
 299                 argv[0] = program;
 300         }
 301
 302         pid = fork();
 303         switch(pid) {
 304         case 0:
 305                 /* child closes parent ends of pipes */
 306                 if (outpipe[READ_END] > 0)
 307                         close(outpipe[READ_END]);
 308                 if (errpipe[READ_END] > 0)
 309                         close(errpipe[READ_END]);
 310
 311                 /* discard child output or connect to pipe */
 312                 devnull = open("/dev/null", O_RDWR);
 313                 if (devnull > 0) {
 314                         dup2(devnull, STDIN_FILENO);
 315                         if (outpipe[WRITE_END] < 0)
 316                                 dup2(devnull, STDOUT_FILENO);
 317                         if (errpipe[WRITE_END] < 0)
 318                                 dup2(devnull, STDERR_FILENO);
 319                         close(devnull);
 320                 } else
 321                         err(udev, "open /dev/null failed: %m\n");
 322                 if (outpipe[WRITE_END] > 0) {
 323                         dup2(outpipe[WRITE_END], STDOUT_FILENO);
 324                         close(outpipe[WRITE_END]);
 325                 }
 326                 if (errpipe[WRITE_END] > 0) {
 327                         dup2(errpipe[WRITE_END], STDERR_FILENO);
 328                         close(errpipe[WRITE_END]);
 329                 }
 330                 execve(argv[0], argv, envp);
 331                 if (errno == ENOENT || errno == ENOTDIR) {
 332                         /* may be on a filesytem which is not mounted right now */
 333                         info(udev, "program '%s' not found\n", argv[0]);
 334                 } else {
 335                         /* other problems */
 336                         err(udev, "exec of program '%s' failed\n", argv[0]);
 337                 }
 338                 _exit(1);
 339         case -1:
 340                 err(udev, "fork of '%s' failed: %m\n", argv[0]);
 341                 return -1;
 342         default:
 343                 /* read from child if requested */
 344                 if (outpipe[READ_END] > 0 || errpipe[READ_END] > 0) {
 345                         ssize_t count;
 346                         size_t respos = 0;
 347
 348                         /* parent closes child ends of pipes */
 349                         if (outpipe[WRITE_END] > 0)
 350                                 close(outpipe[WRITE_END]);
 351                         if (errpipe[WRITE_END] > 0)
 352                                 close(errpipe[WRITE_END]);
 353
 354                         /* read child output */
 355                         while (outpipe[READ_END] > 0 || errpipe[READ_END] > 0) {
 356                                 int fdcount;
 357                                 fd_set readfds;
 358
 359                                 FD_ZERO(&readfds);
 360                                 if (outpipe[READ_END] > 0)
 361                                         FD_SET(outpipe[READ_END], &readfds);
 362                                 if (errpipe[READ_END] > 0)
 363                                         FD_SET(errpipe[READ_END], &readfds);
 364                                 fdcount = select(UDEV_MAX(outpipe[READ_END], errpipe[READ_END])+1, &readfds, NULL, NULL, NULL);
 365                                 if (fdcount < 0) {
 366                                         if (errno == EINTR)
 367                                                 continue;
 368                                         err = -1;
 369                                         break;
 370                                 }
 371
 372                                 /* get stdout */
 373                                 if (outpipe[READ_END] > 0 && FD_ISSET(outpipe[READ_END], &readfds)) {
 374                                         char inbuf[1024];
 375                                         char *pos;
 376                                         char *line;
 377
 378                                         count = read(outpipe[READ_END], inbuf, sizeof(inbuf)-1);
 379                                         if (count <= 0) {
 380                                                 close(outpipe[READ_END]);
 381                                                 outpipe[READ_END] = -1;
 382                                                 if (count < 0) {
 383                                                         err(udev, "stdin read failed: %m\n");
 384                                                         err = -1;
 385                                                 }
 386                                                 continue;
 387                                         }
 388                                         inbuf[count] = '\0';
 389
 390                                         /* store result for rule processing */
 391                                         if (result) {
 392                                                 if (respos + count < ressize) {
 393                                                         memcpy(&result[respos], inbuf, count);
 394                                                         respos += count;
 395                                                 } else {
 396                                                         err(udev, "ressize %ld too short\n", (long)ressize);
 397                                                         err = -1;
 398                                                 }
 399                                         }
 400                                         pos = inbuf;
 401                                         while ((line = strsep(&pos, "\n")))
 402                                                 if (pos || line[0] != '\0')
 403                                                         info(udev, "'%s' (stdout) '%s'\n", argv[0], line);
 404                                 }
 405
 406                                 /* get stderr */
 407                                 if (errpipe[READ_END] > 0 && FD_ISSET(errpipe[READ_END], &readfds)) {
 408                                         char errbuf[1024];
 409                                         char *pos;
 410                                         char *line;
 411
 412                                         count = read(errpipe[READ_END], errbuf, sizeof(errbuf)-1);
 413                                         if (count <= 0) {
 414                                                 close(errpipe[READ_END]);
 415                                                 errpipe[READ_END] = -1;
 416                                                 if (count < 0)
 417                                                         err(udev, "stderr read failed: %m\n");
 418                                                 continue;
 419                                         }
 420                                         errbuf[count] = '\0';
 421                                         pos = errbuf;
 422                                         while ((line = strsep(&pos, "\n")))
 423                                                 if (pos || line[0] != '\0')
 424                                                         info(udev, "'%s' (stderr) '%s'\n", argv[0], line);
 425                                 }
 426                         }
 427                         if (outpipe[READ_END] > 0)
 428                                 close(outpipe[READ_END]);
 429                         if (errpipe[READ_END] > 0)
 430                                 close(errpipe[READ_END]);
 431
 432                         /* return the childs stdout string */
 433                         if (result) {
 434                                 result[respos] = '\0';
 435                                 dbg(udev, "result='%s'\n", result);
 436                                 if (reslen)
 437                                         *reslen = respos;
 438                         }
 439                 }
 440                 waitpid(pid, &status, 0);
 441                 if (WIFEXITED(status)) {
 442                         info(udev, "'%s' returned with status %i\n", argv[0], WEXITSTATUS(status));
 443                         if (WEXITSTATUS(status) != 0)
 444                                 err = -1;
 445                 } else {
 446                         err(udev, "'%s' abnormal exit\n", command);
 447                         err = -1;
 448                 }
 449         }
 450         return err;
 451 }