libudev/libudev-util-private.c

   1 /*
   2  * libudev - interface to udev device information
   3  *
   4  * Copyright (C) 2003-2009 Kay Sievers <kay.sievers@vrfy.org>
   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
  12 #include <stdlib.h>
  13 #include <stdio.h>
  14 #include <stddef.h>
  15 #include <unistd.h>
  16 #include <string.h>
  17 #include <fcntl.h>
  18 #include <errno.h>
  19 #include <ctype.h>
  20 #include <pwd.h>
  21 #include <grp.h>
  22 #include <sys/wait.h>
  23 #include <sys/param.h>
  24
  25 #include "libudev.h"
  26 #include "libudev-private.h"
  27
  28 int util_create_path(struct udev *udev, const char *path)
  29 {
  30         char p[UTIL_PATH_SIZE];
  31         char *pos;
  32         struct stat stats;
  33         int err;
  34
  35         util_strscpy(p, sizeof(p), path);
  36         pos = strrchr(p, '/');
  37         if (pos == NULL)
  38                 return 0;
  39         while (pos != p && pos[-1] == '/')
  40                 pos--;
  41         if (pos == p)
  42                 return 0;
  43         pos[0] = '\0';
  44
  45         dbg(udev, "stat '%s'\n", p);
  46         if (stat(p, &stats) == 0 && (stats.st_mode & S_IFMT) == S_IFDIR)
  47                 return 0;
  48
  49         if (util_create_path(udev, p) != 0)
  50                 return -1;
  51
  52         dbg(udev, "mkdir '%s'\n", p);
  53         udev_selinux_setfscreatecon(udev, p, S_IFDIR|0755);
  54         err = mkdir(p, 0755);
  55         if (err != 0 && errno == EEXIST)
  56                 if (stat(p, &stats) == 0 && (stats.st_mode & S_IFMT) == S_IFDIR)
  57                         err = 0;
  58         udev_selinux_resetfscreatecon(udev);
  59         return err;
  60 }
  61
  62 int util_delete_path(struct udev *udev, const char *path)
  63 {
  64         char p[UTIL_PATH_SIZE];
  65         char *pos;
  66         int retval;
  67
  68         if (path[0] == '/')
  69                 while(path[1] == '/')
  70                         path++;
  71         util_strscpy(p, sizeof(p), path);
  72         pos = strrchr(p, '/');
  73         if (pos == p || pos == NULL)
  74                 return 0;
  75
  76         while (1) {
  77                 *pos = '\0';
  78                 pos = strrchr(p, '/');
  79
  80                 /* don't remove the last one */
  81                 if ((pos == p) || (pos == NULL))
  82                         break;
  83
  84                 /* remove if empty */
  85                 retval = rmdir(p);
  86                 if (errno == ENOENT)
  87                         retval = 0;
  88                 if (retval) {
  89                         if (errno == ENOTEMPTY)
  90                                 return 0;
  91                         err(udev, "rmdir(%s) failed: %m\n", p);
  92                         break;
  93                 }
  94                 dbg(udev, "removed '%s'\n", p);
  95         }
  96         return 0;
  97 }
  98
  99 /* Reset permissions on the device node, before unlinking it to make sure,
 100  * that permissions of possible hard links will be removed too.
 101  */
 102 int util_unlink_secure(struct udev *udev, const char *filename)
 103 {
 104         int err;
 105
 106         chmod(filename, 0000);
 107         chown(filename, 0, 0);
 108         err = unlink(filename);
 109         if (errno == ENOENT)
 110                 err = 0;
 111         if (err)
 112                 err(udev, "unlink(%s) failed: %m\n", filename);
 113         return err;
 114 }
 115
 116 uid_t util_lookup_user(struct udev *udev, const char *user)
 117 {
 118         char *endptr;
 119         int buflen = sysconf(_SC_GETPW_R_SIZE_MAX);
 120         char buf[buflen];
 121         struct passwd pwbuf;
 122         struct passwd *pw;
 123         uid_t uid;
 124
 125         if (strcmp(user, "root") == 0)
 126                 return 0;
 127         uid = strtoul(user, &endptr, 10);
 128         if (endptr[0] == '\0')
 129                 return uid;
 130
 131         errno = getpwnam_r(user, &pwbuf, buf, buflen, &pw);
 132         if (pw != NULL)
 133                 return pw->pw_uid;
 134         if (errno == 0 || errno == ENOENT || errno == ESRCH)
 135                 err(udev, "specified user '%s' unknown\n", user);
 136         else
 137                 err(udev, "error resolving user '%s': %m\n", user);
 138         return 0;
 139 }
 140
 141 gid_t util_lookup_group(struct udev *udev, const char *group)
 142 {
 143         char *endptr;
 144         int buflen = sysconf(_SC_GETGR_R_SIZE_MAX);
 145         char *buf;
 146         struct group grbuf;
 147         struct group *gr;
 148         gid_t gid = 0;
 149
 150         if (strcmp(group, "root") == 0)
 151                 return 0;
 152         gid = strtoul(group, &endptr, 10);
 153         if (endptr[0] == '\0')
 154                 return gid;
 155         buf = NULL;
 156         gid = 0;
 157         for (;;) {
 158                 char *newbuf;
 159
 160                 newbuf = realloc(buf, buflen);
 161                 if (!newbuf)
 162                         break;
 163                 buf = newbuf;
 164                 errno = getgrnam_r(group, &grbuf, buf, buflen, &gr);
 165                 if (gr != NULL) {
 166                         gid = gr->gr_gid;
 167                 } else if (errno == ERANGE) {
 168                         buflen *= 2;
 169                         continue;
 170                 } else if (errno == 0 || errno == ENOENT || errno == ESRCH) {
 171                         err(udev, "specified group '%s' unknown\n", group);
 172                 } else {
 173                         err(udev, "error resolving group '%s': %m\n", group);
 174                 }
 175                 break;
 176         }
 177         free(buf);
 178         return gid;
 179 }
 180
 181 /* handle "[<SUBSYSTEM>/<KERNEL>]<attribute>" format */
 182 int util_resolve_subsys_kernel(struct udev *udev, const char *string,
 183                                char *result, size_t maxsize, int read_value)
 184 {
 185         char temp[UTIL_PATH_SIZE];
 186         char *subsys;
 187         char *sysname;
 188         struct udev_device *dev;
 189         char *attr;
 190
 191         if (string[0] != '[')
 192                 return -1;
 193
 194         util_strscpy(temp, sizeof(temp), string);
 195
 196         subsys = &temp[1];
 197
 198         sysname = strchr(subsys, '/');
 199         if (sysname == NULL)
 200                 return -1;
 201         sysname[0] = '\0';
 202         sysname = &sysname[1];
 203
 204         attr = strchr(sysname, ']');
 205         if (attr == NULL)
 206                 return -1;
 207         attr[0] = '\0';
 208         attr = &attr[1];
 209         if (attr[0] == '/')
 210                 attr = &attr[1];
 211         if (attr[0] == '\0')
 212                 attr = NULL;
 213
 214         if (read_value && attr == NULL)
 215                 return -1;
 216
 217         dev = udev_device_new_from_subsystem_sysname(udev, subsys, sysname);
 218         if (dev == NULL)
 219                 return -1;
 220
 221         if (read_value) {
 222                 const char *val;
 223
 224                 val = udev_device_get_sysattr_value(dev, attr);
 225                 if (val != NULL)
 226                         util_strscpy(result, maxsize, val);
 227                 else
 228                         result[0] = '\0';
 229                 info(udev, "value '[%s/%s]%s' is '%s'\n", subsys, sysname, attr, result);
 230         } else {
 231                 size_t l;
 232                 char *s;
 233
 234                 s = result;
 235                 l = util_strpcpyl(&s, maxsize, udev_device_get_syspath(dev), NULL);
 236                 if (attr != NULL)
 237                         util_strpcpyl(&s, l, "/", attr, NULL);
 238                 info(udev, "path '[%s/%s]%s' is '%s'\n", subsys, sysname, attr, result);
 239         }
 240         udev_device_unref(dev);
 241         return 0;
 242 }
 243
 244 int util_run_program(struct udev *udev, const char *command, char **envp,
 245                      char *result, size_t ressize, size_t *reslen,
 246                      const sigset_t *sigmask)
 247 {
 248         int status;
 249         int outpipe[2] = {-1, -1};
 250         int errpipe[2] = {-1, -1};
 251         pid_t pid;
 252         char arg[UTIL_PATH_SIZE];
 253         char program[UTIL_PATH_SIZE];
 254         char *argv[(sizeof(arg) / 2) + 1];
 255         int devnull;
 256         int i;
 257         int err = 0;
 258
 259         info(udev, "'%s' started\n", command);
 260
 261         /* build argv from command */
 262         util_strscpy(arg, sizeof(arg), command);
 263         i = 0;
 264         if (strchr(arg, ' ') != NULL) {
 265                 char *pos = arg;
 266
 267                 while (pos != NULL && pos[0] != '\0') {
 268                         if (pos[0] == '\'') {
 269                                 /* do not separate quotes */
 270                                 pos++;
 271                                 argv[i] = strsep(&pos, "\'");
 272                                 while (pos != NULL && pos[0] == ' ')
 273                                         pos++;
 274                         } else {
 275                                 argv[i] = strsep(&pos, " ");
 276                         }
 277                         dbg(udev, "arg[%i] '%s'\n", i, argv[i]);
 278                         i++;
 279                 }
 280                 argv[i] = NULL;
 281         } else {
 282                 argv[0] = arg;
 283                 argv[1] = NULL;
 284         }
 285
 286         /* prepare pipes from child to parent */
 287         if (result != NULL || udev_get_log_priority(udev) >= LOG_INFO) {
 288                 if (pipe(outpipe) != 0) {
 289                         err(udev, "pipe failed: %m\n");
 290                         return -1;
 291                 }
 292         }
 293         if (udev_get_log_priority(udev) >= LOG_INFO) {
 294                 if (pipe(errpipe) != 0) {
 295                         err(udev, "pipe failed: %m\n");
 296                         return -1;
 297                 }
 298         }
 299
 300         /* allow programs in /lib/udev/ to be called without the path */
 301         if (argv[0][0] != '/') {
 302                 util_strscpyl(program, sizeof(program), LIBEXECDIR "/", argv[0], NULL);
 303                 argv[0] = program;
 304         }
 305
 306         pid = fork();
 307         switch(pid) {
 308         case 0:
 309                 /* child closes parent ends of pipes */
 310                 if (outpipe[READ_END] > 0)
 311                         close(outpipe[READ_END]);
 312                 if (errpipe[READ_END] > 0)
 313                         close(errpipe[READ_END]);
 314
 315                 /* discard child output or connect to pipe */
 316                 devnull = open("/dev/null", O_RDWR);
 317                 if (devnull > 0) {
 318                         dup2(devnull, STDIN_FILENO);
 319                         if (outpipe[WRITE_END] < 0)
 320                                 dup2(devnull, STDOUT_FILENO);
 321                         if (errpipe[WRITE_END] < 0)
 322                                 dup2(devnull, STDERR_FILENO);
 323                         close(devnull);
 324                 } else
 325                         err(udev, "open /dev/null failed: %m\n");
 326                 if (outpipe[WRITE_END] > 0) {
 327                         dup2(outpipe[WRITE_END], STDOUT_FILENO);
 328                         close(outpipe[WRITE_END]);
 329                 }
 330                 if (errpipe[WRITE_END] > 0) {
 331                         dup2(errpipe[WRITE_END], STDERR_FILENO);
 332                         close(errpipe[WRITE_END]);
 333                 }
 334
 335                 if (sigmask)
 336                         sigprocmask(SIG_BLOCK, sigmask, NULL);
 337
 338                 execve(argv[0], argv, envp);
 339                 if (errno == ENOENT || errno == ENOTDIR) {
 340                         /* may be on a filesystem which is not mounted right now */
 341                         info(udev, "program '%s' not found\n", argv[0]);
 342                 } else {
 343                         /* other problems */
 344                         err(udev, "exec of program '%s' failed\n", argv[0]);
 345                 }
 346                 _exit(1);
 347         case -1:
 348                 err(udev, "fork of '%s' failed: %m\n", argv[0]);
 349                 return -1;
 350         default:
 351                 /* read from child if requested */
 352                 if (outpipe[READ_END] > 0 || errpipe[READ_END] > 0) {
 353                         ssize_t count;
 354                         size_t respos = 0;
 355
 356                         /* parent closes child ends of pipes */
 357                         if (outpipe[WRITE_END] > 0)
 358                                 close(outpipe[WRITE_END]);
 359                         if (errpipe[WRITE_END] > 0)
 360                                 close(errpipe[WRITE_END]);
 361
 362                         /* read child output */
 363                         while (outpipe[READ_END] > 0 || errpipe[READ_END] > 0) {
 364                                 int fdcount;
 365                                 fd_set readfds;
 366
 367                                 FD_ZERO(&readfds);
 368                                 if (outpipe[READ_END] > 0)
 369                                         FD_SET(outpipe[READ_END], &readfds);
 370                                 if (errpipe[READ_END] > 0)
 371                                         FD_SET(errpipe[READ_END], &readfds);
 372                                 fdcount = select(MAX(outpipe[READ_END], errpipe[READ_END])+1, &readfds, NULL, NULL, NULL);
 373                                 if (fdcount < 0) {
 374                                         if (errno == EINTR)
 375                                                 continue;
 376                                         err = -1;
 377                                         break;
 378                                 }
 379
 380                                 /* get stdout */
 381                                 if (outpipe[READ_END] > 0 && FD_ISSET(outpipe[READ_END], &readfds)) {
 382                                         char inbuf[1024];
 383                                         char *pos;
 384                                         char *line;
 385
 386                                         count = read(outpipe[READ_END], inbuf, sizeof(inbuf)-1);
 387                                         if (count <= 0) {
 388                                                 close(outpipe[READ_END]);
 389                                                 outpipe[READ_END] = -1;
 390                                                 if (count < 0) {
 391                                                         err(udev, "stdin read failed: %m\n");
 392                                                         err = -1;
 393                                                 }
 394                                                 continue;
 395                                         }
 396                                         inbuf[count] = '\0';
 397
 398                                         /* store result for rule processing */
 399                                         if (result) {
 400                                                 if (respos + count < ressize) {
 401                                                         memcpy(&result[respos], inbuf, count);
 402                                                         respos += count;
 403                                                 } else {
 404                                                         err(udev, "ressize %ld too short\n", (long)ressize);
 405                                                         err = -1;
 406                                                 }
 407                                         }
 408                                         pos = inbuf;
 409                                         while ((line = strsep(&pos, "\n")))
 410                                                 if (pos || line[0] != '\0')
 411                                                         info(udev, "'%s' (stdout) '%s'\n", argv[0], line);
 412                                 }
 413
 414                                 /* get stderr */
 415                                 if (errpipe[READ_END] > 0 && FD_ISSET(errpipe[READ_END], &readfds)) {
 416                                         char errbuf[1024];
 417                                         char *pos;
 418                                         char *line;
 419
 420                                         count = read(errpipe[READ_END], errbuf, sizeof(errbuf)-1);
 421                                         if (count <= 0) {
 422                                                 close(errpipe[READ_END]);
 423                                                 errpipe[READ_END] = -1;
 424                                                 if (count < 0)
 425                                                         err(udev, "stderr read failed: %m\n");
 426                                                 continue;
 427                                         }
 428                                         errbuf[count] = '\0';
 429                                         pos = errbuf;
 430                                         while ((line = strsep(&pos, "\n")))
 431                                                 if (pos || line[0] != '\0')
 432                                                         info(udev, "'%s' (stderr) '%s'\n", argv[0], line);
 433                                 }
 434                         }
 435                         if (outpipe[READ_END] > 0)
 436                                 close(outpipe[READ_END]);
 437                         if (errpipe[READ_END] > 0)
 438                                 close(errpipe[READ_END]);
 439
 440                         /* return the childs stdout string */
 441                         if (result) {
 442                                 result[respos] = '\0';
 443                                 dbg(udev, "result='%s'\n", result);
 444                                 if (reslen)
 445                                         *reslen = respos;
 446                         }
 447                 }
 448                 waitpid(pid, &status, 0);
 449                 if (WIFEXITED(status)) {
 450                         info(udev, "'%s' returned with exitcode %i\n", command, WEXITSTATUS(status));
 451                         if (WEXITSTATUS(status) != 0)
 452                                 err = -1;
 453                 } else {
 454                         err(udev, "'%s' unexpected exit with status 0x%04x\n", command, status);
 455                         err = -1;
 456                 }
 457         }
 458         return err;
 459 }