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