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         int buflen = sysconf(_SC_GETPW_R_SIZE_MAX);
 130         char buf[buflen];
 131         struct passwd pwbuf;
 132         struct passwd *pw;
 133         uid_t uid = 0;
 134
 135         if (strcmp(user, "root") == 0)
 136                 return 0;
 137         errno = 0;
 138         getpwnam_r(user, &pwbuf, buf, buflen, &pw);
 139         if (pw == NULL) {
 140                 if (errno == 0 || errno == ENOENT || errno == ESRCH)
 141                         err(udev, "specified user '%s' unknown\n", user);
 142                 else
 143                         err(udev, "error resolving user '%s': %m\n", user);
 144         } else
 145                 uid = pw->pw_uid;
 146
 147         return uid;
 148 }
 149
 150 extern gid_t util_lookup_group(struct udev *udev, const char *group)
 151 {
 152         int buflen = sysconf(_SC_GETGR_R_SIZE_MAX);
 153         char buf[buflen];
 154         struct group grbuf;
 155         struct group *gr;
 156         gid_t gid = 0;
 157
 158         if (strcmp(group, "root") == 0)
 159                 return 0;
 160         errno = 0;
 161         getgrnam_r(group, &grbuf, buf, buflen, &gr);
 162         if (gr == NULL) {
 163                 if (errno == 0 || errno == ENOENT || errno == ESRCH)
 164                         err(udev, "specified group '%s' unknown\n", group);
 165                 else
 166                         err(udev, "error resolving group '%s': %m\n", group);
 167         } else
 168                 gid = gr->gr_gid;
 169         return gid;
 170 }
 171
 172 /* handle "[<SUBSYSTEM>/<KERNEL>]<attribute>" format */
 173 int util_resolve_subsys_kernel(struct udev *udev, const char *string,
 174                                char *result, size_t maxsize, int read_value)
 175 {
 176         char temp[UTIL_PATH_SIZE];
 177         char *subsys;
 178         char *sysname;
 179         struct udev_device *dev;
 180         char *attr;
 181
 182         if (string == NULL)
 183                 string = result;
 184         if (string[0] != '[')
 185                 return -1;
 186
 187         util_strlcpy(temp, string, sizeof(temp));
 188
 189         subsys = &temp[1];
 190
 191         sysname = strchr(subsys, '/');
 192         if (sysname == NULL)
 193                 return -1;
 194         sysname[0] = '\0';
 195         sysname = &sysname[1];
 196
 197         attr = strchr(sysname, ']');
 198         if (attr == NULL)
 199                 return -1;
 200         attr[0] = '\0';
 201         attr = &attr[1];
 202         if (attr[0] == '/')
 203                 attr = &attr[1];
 204         if (attr[0] == '\0')
 205                 attr = NULL;
 206
 207         if (read_value && attr == NULL)
 208                 return -1;
 209
 210         dev = udev_device_new_from_subsystem_sysname(udev, subsys, sysname);
 211         if (dev == NULL)
 212                 return -1;
 213
 214         if (read_value) {
 215                 const char *val;
 216
 217                 val = udev_device_get_sysattr_value(dev, attr);
 218                 if (val != NULL)
 219                         util_strlcpy(result, val, maxsize);
 220                 else
 221                         result[0] = '\0';
 222                 info(udev, "value '[%s/%s]%s' is '%s'\n", subsys, sysname, attr, result);
 223         } else {
 224                 util_strlcpy(result, udev_device_get_syspath(dev), maxsize);
 225                 if (attr != NULL) {
 226                         util_strlcat(result, "/", maxsize);
 227                         util_strlcat(result, attr, maxsize);
 228                 }
 229                 info(udev, "path '[%s/%s]%s' is '%s'\n", subsys, sysname, attr, result);
 230         }
 231         udev_device_unref(dev);
 232         return 0;
 233 }
 234
 235 int util_run_program(struct udev *udev, const char *command, char **envp,
 236                      char *result, size_t ressize, size_t *reslen)
 237 {
 238         int status;
 239         int outpipe[2] = {-1, -1};
 240         int errpipe[2] = {-1, -1};
 241         pid_t pid;
 242         char arg[UTIL_PATH_SIZE];
 243         char program[UTIL_PATH_SIZE];
 244         char *argv[(sizeof(arg) / 2) + 1];
 245         int devnull;
 246         int i;
 247         int err = 0;
 248
 249         /* build argv from command */
 250         util_strlcpy(arg, command, sizeof(arg));
 251         i = 0;
 252         if (strchr(arg, ' ') != NULL) {
 253                 char *pos = arg;
 254
 255                 while (pos != NULL && pos[0] != '\0') {
 256                         if (pos[0] == '\'') {
 257                                 /* do not separate quotes */
 258                                 pos++;
 259                                 argv[i] = strsep(&pos, "\'");
 260                                 while (pos != NULL && pos[0] == ' ')
 261                                         pos++;
 262                         } else {
 263                                 argv[i] = strsep(&pos, " ");
 264                         }
 265                         dbg(udev, "arg[%i] '%s'\n", i, argv[i]);
 266                         i++;
 267                 }
 268                 argv[i] = NULL;
 269         } else {
 270                 argv[0] = arg;
 271                 argv[1] = NULL;
 272         }
 273         info(udev, "'%s'\n", command);
 274
 275         /* prepare pipes from child to parent */
 276         if (result != NULL || udev_get_log_priority(udev) >= LOG_INFO) {
 277                 if (pipe(outpipe) != 0) {
 278                         err(udev, "pipe failed: %m\n");
 279                         return -1;
 280                 }
 281         }
 282         if (udev_get_log_priority(udev) >= LOG_INFO) {
 283                 if (pipe(errpipe) != 0) {
 284                         err(udev, "pipe failed: %m\n");
 285                         return -1;
 286                 }
 287         }
 288
 289         /* allow programs in /lib/udev/ to be called without the path */
 290         if (strchr(argv[0], '/') == NULL) {
 291                 util_strlcpy(program, UDEV_PREFIX "/lib/udev/", sizeof(program));
 292                 util_strlcat(program, argv[0], sizeof(program));
 293                 argv[0] = program;
 294         }
 295
 296         pid = fork();
 297         switch(pid) {
 298         case 0:
 299                 /* child closes parent ends of pipes */
 300                 if (outpipe[READ_END] > 0)
 301                         close(outpipe[READ_END]);
 302                 if (errpipe[READ_END] > 0)
 303                         close(errpipe[READ_END]);
 304
 305                 /* discard child output or connect to pipe */
 306                 devnull = open("/dev/null", O_RDWR);
 307                 if (devnull > 0) {
 308                         dup2(devnull, STDIN_FILENO);
 309                         if (outpipe[WRITE_END] < 0)
 310                                 dup2(devnull, STDOUT_FILENO);
 311                         if (errpipe[WRITE_END] < 0)
 312                                 dup2(devnull, STDERR_FILENO);
 313                         close(devnull);
 314                 } else
 315                         err(udev, "open /dev/null failed: %m\n");
 316                 if (outpipe[WRITE_END] > 0) {
 317                         dup2(outpipe[WRITE_END], STDOUT_FILENO);
 318                         close(outpipe[WRITE_END]);
 319                 }
 320                 if (errpipe[WRITE_END] > 0) {
 321                         dup2(errpipe[WRITE_END], STDERR_FILENO);
 322                         close(errpipe[WRITE_END]);
 323                 }
 324                 execve(argv[0], argv, envp);
 325                 if (errno == ENOENT || errno == ENOTDIR) {
 326                         /* may be on a filesytem which is not mounted right now */
 327                         info(udev, "program '%s' not found\n", argv[0]);
 328                 } else {
 329                         /* other problems */
 330                         err(udev, "exec of program '%s' failed\n", argv[0]);
 331                 }
 332                 _exit(1);
 333         case -1:
 334                 err(udev, "fork of '%s' failed: %m\n", argv[0]);
 335                 return -1;
 336         default:
 337                 /* read from child if requested */
 338                 if (outpipe[READ_END] > 0 || errpipe[READ_END] > 0) {
 339                         ssize_t count;
 340                         size_t respos = 0;
 341
 342                         /* parent closes child ends of pipes */
 343                         if (outpipe[WRITE_END] > 0)
 344                                 close(outpipe[WRITE_END]);
 345                         if (errpipe[WRITE_END] > 0)
 346                                 close(errpipe[WRITE_END]);
 347
 348                         /* read child output */
 349                         while (outpipe[READ_END] > 0 || errpipe[READ_END] > 0) {
 350                                 int fdcount;
 351                                 fd_set readfds;
 352
 353                                 FD_ZERO(&readfds);
 354                                 if (outpipe[READ_END] > 0)
 355                                         FD_SET(outpipe[READ_END], &readfds);
 356                                 if (errpipe[READ_END] > 0)
 357                                         FD_SET(errpipe[READ_END], &readfds);
 358                                 fdcount = select(UDEV_MAX(outpipe[READ_END], errpipe[READ_END])+1, &readfds, NULL, NULL, NULL);
 359                                 if (fdcount < 0) {
 360                                         if (errno == EINTR)
 361                                                 continue;
 362                                         err = -1;
 363                                         break;
 364                                 }
 365
 366                                 /* get stdout */
 367                                 if (outpipe[READ_END] > 0 && FD_ISSET(outpipe[READ_END], &readfds)) {
 368                                         char inbuf[1024];
 369                                         char *pos;
 370                                         char *line;
 371
 372                                         count = read(outpipe[READ_END], inbuf, sizeof(inbuf)-1);
 373                                         if (count <= 0) {
 374                                                 close(outpipe[READ_END]);
 375                                                 outpipe[READ_END] = -1;
 376                                                 if (count < 0) {
 377                                                         err(udev, "stdin read failed: %m\n");
 378                                                         err = -1;
 379                                                 }
 380                                                 continue;
 381                                         }
 382                                         inbuf[count] = '\0';
 383
 384                                         /* store result for rule processing */
 385                                         if (result) {
 386                                                 if (respos + count < ressize) {
 387                                                         memcpy(&result[respos], inbuf, count);
 388                                                         respos += count;
 389                                                 } else {
 390                                                         err(udev, "ressize %ld too short\n", (long)ressize);
 391                                                         err = -1;
 392                                                 }
 393                                         }
 394                                         pos = inbuf;
 395                                         while ((line = strsep(&pos, "\n")))
 396                                                 if (pos || line[0] != '\0')
 397                                                         info(udev, "'%s' (stdout) '%s'\n", argv[0], line);
 398                                 }
 399
 400                                 /* get stderr */
 401                                 if (errpipe[READ_END] > 0 && FD_ISSET(errpipe[READ_END], &readfds)) {
 402                                         char errbuf[1024];
 403                                         char *pos;
 404                                         char *line;
 405
 406                                         count = read(errpipe[READ_END], errbuf, sizeof(errbuf)-1);
 407                                         if (count <= 0) {
 408                                                 close(errpipe[READ_END]);
 409                                                 errpipe[READ_END] = -1;
 410                                                 if (count < 0)
 411                                                         err(udev, "stderr read failed: %m\n");
 412                                                 continue;
 413                                         }
 414                                         errbuf[count] = '\0';
 415                                         pos = errbuf;
 416                                         while ((line = strsep(&pos, "\n")))
 417                                                 if (pos || line[0] != '\0')
 418                                                         info(udev, "'%s' (stderr) '%s'\n", argv[0], line);
 419                                 }
 420                         }
 421                         if (outpipe[READ_END] > 0)
 422                                 close(outpipe[READ_END]);
 423                         if (errpipe[READ_END] > 0)
 424                                 close(errpipe[READ_END]);
 425
 426                         /* return the childs stdout string */
 427                         if (result) {
 428                                 result[respos] = '\0';
 429                                 dbg(udev, "result='%s'\n", result);
 430                                 if (reslen)
 431                                         *reslen = respos;
 432                         }
 433                 }
 434                 waitpid(pid, &status, 0);
 435                 if (WIFEXITED(status)) {
 436                         info(udev, "'%s' returned with status %i\n", argv[0], WEXITSTATUS(status));
 437                         if (WEXITSTATUS(status) != 0)
 438                                 err = -1;
 439                 } else {
 440                         err(udev, "'%s' abnormal exit\n", argv[0]);
 441                         err = -1;
 442                 }
 443         }
 444         return err;
 445 }