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_strlcpy(p, path, sizeof(p));
  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         struct passwd *pw;
 130         uid_t uid = 0;
 131
 132         if (strcmp(user, "root") == 0)
 133                 return 0;
 134         errno = 0;
 135         pw = getpwnam(user);
 136         if (pw == NULL) {
 137                 if (errno == 0 || errno == ENOENT || errno == ESRCH)
 138                         err(udev, "specified user '%s' unknown\n", user);
 139                 else
 140                         err(udev, "error resolving user '%s': %m\n", user);
 141         } else
 142                 uid = pw->pw_uid;
 143         return uid;
 144 }
 145
 146 extern gid_t util_lookup_group(struct udev *udev, const char *group)
 147 {
 148         struct group *gr;
 149         gid_t gid = 0;
 150
 151         if (strcmp(group, "root") == 0)
 152                 return 0;
 153         errno = 0;
 154         gr = getgrnam(group);
 155         if (gr == NULL) {
 156                 if (errno == 0 || errno == ENOENT || errno == ESRCH)
 157                         err(udev, "specified group '%s' unknown\n", group);
 158                 else
 159                         err(udev, "error resolving group '%s': %m\n", group);
 160         } else
 161                 gid = gr->gr_gid;
 162         return gid;
 163 }
 164
 165 /* handle "[<SUBSYSTEM>/<KERNEL>]<attribute>" format */
 166 int util_resolve_subsys_kernel(struct udev *udev, const char *string,
 167                                char *result, size_t maxsize, int read_value)
 168 {
 169         char temp[UTIL_PATH_SIZE];
 170         char *subsys;
 171         char *sysname;
 172         struct udev_device *dev;
 173         char *attr;
 174
 175         if (string == NULL)
 176                 string = result;
 177         if (string[0] != '[')
 178                 return -1;
 179
 180         util_strlcpy(temp, string, sizeof(temp));
 181
 182         subsys = &temp[1];
 183
 184         sysname = strchr(subsys, '/');
 185         if (sysname == NULL)
 186                 return -1;
 187         sysname[0] = '\0';
 188         sysname = &sysname[1];
 189
 190         attr = strchr(sysname, ']');
 191         if (attr == NULL)
 192                 return -1;
 193         attr[0] = '\0';
 194         attr = &attr[1];
 195         if (attr[0] == '/')
 196                 attr = &attr[1];
 197         if (attr[0] == '\0')
 198                 attr = NULL;
 199
 200         if (read_value && attr == NULL)
 201                 return -1;
 202
 203         dev = udev_device_new_from_subsystem_sysname(udev, subsys, sysname);
 204         if (dev == NULL)
 205                 return -1;
 206
 207         if (read_value) {
 208                 const char *val;
 209
 210                 val = udev_device_get_sysattr_value(dev, attr);
 211                 if (val != NULL)
 212                         util_strlcpy(result, val, maxsize);
 213                 else
 214                         result[0] = '\0';
 215                 info(udev, "value '[%s/%s]%s' is '%s'\n", subsys, sysname, attr, result);
 216         } else {
 217                 util_strlcpy(result, udev_device_get_syspath(dev), maxsize);
 218                 if (attr != NULL) {
 219                         util_strlcat(result, "/", maxsize);
 220                         util_strlcat(result, attr, maxsize);
 221                 }
 222                 info(udev, "path '[%s/%s]%s' is '%s'\n", subsys, sysname, attr, result);
 223         }
 224         udev_device_unref(dev);
 225         return 0;
 226 }
 227
 228 int util_run_program(struct udev *udev, const char *command, char **envp,
 229                      char *result, size_t ressize, size_t *reslen)
 230 {
 231         int status;
 232         int outpipe[2] = {-1, -1};
 233         int errpipe[2] = {-1, -1};
 234         pid_t pid;
 235         char arg[UTIL_PATH_SIZE];
 236         char program[UTIL_PATH_SIZE];
 237         char *argv[(sizeof(arg) / 2) + 1];
 238         int devnull;
 239         int i;
 240         int err = 0;
 241
 242         /* build argv from command */
 243         util_strlcpy(arg, command, sizeof(arg));
 244         i = 0;
 245         if (strchr(arg, ' ') != NULL) {
 246                 char *pos = arg;
 247
 248                 while (pos != NULL && pos[0] != '\0') {
 249                         if (pos[0] == '\'') {
 250                                 /* do not separate quotes */
 251                                 pos++;
 252                                 argv[i] = strsep(&pos, "\'");
 253                                 while (pos != NULL && pos[0] == ' ')
 254                                         pos++;
 255                         } else {
 256                                 argv[i] = strsep(&pos, " ");
 257                         }
 258                         dbg(udev, "arg[%i] '%s'\n", i, argv[i]);
 259                         i++;
 260                 }
 261                 argv[i] = NULL;
 262         } else {
 263                 argv[0] = arg;
 264                 argv[1] = NULL;
 265         }
 266         info(udev, "'%s'\n", command);
 267
 268         /* prepare pipes from child to parent */
 269         if (result != NULL || udev_get_log_priority(udev) >= LOG_INFO) {
 270                 if (pipe(outpipe) != 0) {
 271                         err(udev, "pipe failed: %m\n");
 272                         return -1;
 273                 }
 274         }
 275         if (udev_get_log_priority(udev) >= LOG_INFO) {
 276                 if (pipe(errpipe) != 0) {
 277                         err(udev, "pipe failed: %m\n");
 278                         return -1;
 279                 }
 280         }
 281
 282         /* allow programs in /lib/udev/ to be called without the path */
 283         if (strchr(argv[0], '/') == NULL) {
 284                 util_strlcpy(program, UDEV_PREFIX "/lib/udev/", sizeof(program));
 285                 util_strlcat(program, argv[0], sizeof(program));
 286                 argv[0] = program;
 287         }
 288
 289         pid = fork();
 290         switch(pid) {
 291         case 0:
 292                 /* child closes parent ends of pipes */
 293                 if (outpipe[READ_END] > 0)
 294                         close(outpipe[READ_END]);
 295                 if (errpipe[READ_END] > 0)
 296                         close(errpipe[READ_END]);
 297
 298                 /* discard child output or connect to pipe */
 299                 devnull = open("/dev/null", O_RDWR);
 300                 if (devnull > 0) {
 301                         dup2(devnull, STDIN_FILENO);
 302                         if (outpipe[WRITE_END] < 0)
 303                                 dup2(devnull, STDOUT_FILENO);
 304                         if (errpipe[WRITE_END] < 0)
 305                                 dup2(devnull, STDERR_FILENO);
 306                         close(devnull);
 307                 } else
 308                         err(udev, "open /dev/null failed: %m\n");
 309                 if (outpipe[WRITE_END] > 0) {
 310                         dup2(outpipe[WRITE_END], STDOUT_FILENO);
 311                         close(outpipe[WRITE_END]);
 312                 }
 313                 if (errpipe[WRITE_END] > 0) {
 314                         dup2(errpipe[WRITE_END], STDERR_FILENO);
 315                         close(errpipe[WRITE_END]);
 316                 }
 317                 execve(argv[0], argv, envp);
 318                 if (errno == ENOENT || errno == ENOTDIR) {
 319                         /* may be on a filesytem which is not mounted right now */
 320                         info(udev, "program '%s' not found\n", argv[0]);
 321                 } else {
 322                         /* other problems */
 323                         err(udev, "exec of program '%s' failed\n", argv[0]);
 324                 }
 325                 _exit(1);
 326         case -1:
 327                 err(udev, "fork of '%s' failed: %m\n", argv[0]);
 328                 return -1;
 329         default:
 330                 /* read from child if requested */
 331                 if (outpipe[READ_END] > 0 || errpipe[READ_END] > 0) {
 332                         ssize_t count;
 333                         size_t respos = 0;
 334
 335                         /* parent closes child ends of pipes */
 336                         if (outpipe[WRITE_END] > 0)
 337                                 close(outpipe[WRITE_END]);
 338                         if (errpipe[WRITE_END] > 0)
 339                                 close(errpipe[WRITE_END]);
 340
 341                         /* read child output */
 342                         while (outpipe[READ_END] > 0 || errpipe[READ_END] > 0) {
 343                                 int fdcount;
 344                                 fd_set readfds;
 345
 346                                 FD_ZERO(&readfds);
 347                                 if (outpipe[READ_END] > 0)
 348                                         FD_SET(outpipe[READ_END], &readfds);
 349                                 if (errpipe[READ_END] > 0)
 350                                         FD_SET(errpipe[READ_END], &readfds);
 351                                 fdcount = select(UDEV_MAX(outpipe[READ_END], errpipe[READ_END])+1, &readfds, NULL, NULL, NULL);
 352                                 if (fdcount < 0) {
 353                                         if (errno == EINTR)
 354                                                 continue;
 355                                         err = -1;
 356                                         break;
 357                                 }
 358
 359                                 /* get stdout */
 360                                 if (outpipe[READ_END] > 0 && FD_ISSET(outpipe[READ_END], &readfds)) {
 361                                         char inbuf[1024];
 362                                         char *pos;
 363                                         char *line;
 364
 365                                         count = read(outpipe[READ_END], inbuf, sizeof(inbuf)-1);
 366                                         if (count <= 0) {
 367                                                 close(outpipe[READ_END]);
 368                                                 outpipe[READ_END] = -1;
 369                                                 if (count < 0) {
 370                                                         err(udev, "stdin read failed: %m\n");
 371                                                         err = -1;
 372                                                 }
 373                                                 continue;
 374                                         }
 375                                         inbuf[count] = '\0';
 376
 377                                         /* store result for rule processing */
 378                                         if (result) {
 379                                                 if (respos + count < ressize) {
 380                                                         memcpy(&result[respos], inbuf, count);
 381                                                         respos += count;
 382                                                 } else {
 383                                                         err(udev, "ressize %ld too short\n", (long)ressize);
 384                                                         err = -1;
 385                                                 }
 386                                         }
 387                                         pos = inbuf;
 388                                         while ((line = strsep(&pos, "\n")))
 389                                                 if (pos || line[0] != '\0')
 390                                                         info(udev, "'%s' (stdout) '%s'\n", argv[0], line);
 391                                 }
 392
 393                                 /* get stderr */
 394                                 if (errpipe[READ_END] > 0 && FD_ISSET(errpipe[READ_END], &readfds)) {
 395                                         char errbuf[1024];
 396                                         char *pos;
 397                                         char *line;
 398
 399                                         count = read(errpipe[READ_END], errbuf, sizeof(errbuf)-1);
 400                                         if (count <= 0) {
 401                                                 close(errpipe[READ_END]);
 402                                                 errpipe[READ_END] = -1;
 403                                                 if (count < 0)
 404                                                         err(udev, "stderr read failed: %m\n");
 405                                                 continue;
 406                                         }
 407                                         errbuf[count] = '\0';
 408                                         pos = errbuf;
 409                                         while ((line = strsep(&pos, "\n")))
 410                                                 if (pos || line[0] != '\0')
 411                                                         info(udev, "'%s' (stderr) '%s'\n", argv[0], line);
 412                                 }
 413                         }
 414                         if (outpipe[READ_END] > 0)
 415                                 close(outpipe[READ_END]);
 416                         if (errpipe[READ_END] > 0)
 417                                 close(errpipe[READ_END]);
 418
 419                         /* return the childs stdout string */
 420                         if (result) {
 421                                 result[respos] = '\0';
 422                                 dbg(udev, "result='%s'\n", result);
 423                                 if (reslen)
 424                                         *reslen = respos;
 425                         }
 426                 }
 427                 waitpid(pid, &status, 0);
 428                 if (WIFEXITED(status)) {
 429                         info(udev, "'%s' returned with status %i\n", argv[0], WEXITSTATUS(status));
 430                         if (WEXITSTATUS(status) != 0)
 431                                 err = -1;
 432                 } else {
 433                         err(udev, "'%s' abnormal exit\n", argv[0]);
 434                         err = -1;
 435                 }
 436         }
 437         return err;
 438 }