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) {
  47                 if ((stats.st_mode & S_IFMT) == S_IFDIR)
  48                         return 0;
  49                 else
  50                         return -ENOTDIR;
  51         }
  52
  53         err = util_create_path(udev, p);
  54         if (err != 0)
  55                 return err;
  56
  57         dbg(udev, "mkdir '%s'\n", p);
  58         udev_selinux_setfscreatecon(udev, p, S_IFDIR|0755);
  59         err = mkdir(p, 0755);
  60         if (err != 0) {
  61                 err = -errno;
  62                 if (err == -EEXIST && stat(p, &stats) == 0) {
  63                         if ((stats.st_mode & S_IFMT) == S_IFDIR)
  64                                 err = 0;
  65                         else
  66                                 err = -ENOTDIR;
  67                 }
  68         }
  69         udev_selinux_resetfscreatecon(udev);
  70         return err;
  71 }
  72
  73 int util_delete_path(struct udev *udev, const char *path)
  74 {
  75         char p[UTIL_PATH_SIZE];
  76         char *pos;
  77         int err = 0;
  78
  79         if (path[0] == '/')
  80                 while(path[1] == '/')
  81                         path++;
  82         util_strscpy(p, sizeof(p), path);
  83         pos = strrchr(p, '/');
  84         if (pos == p || pos == NULL)
  85                 return 0;
  86
  87         for (;;) {
  88                 *pos = '\0';
  89                 pos = strrchr(p, '/');
  90
  91                 /* don't remove the last one */
  92                 if ((pos == p) || (pos == NULL))
  93                         break;
  94
  95                 err = rmdir(p);
  96                 if (err < 0) {
  97                         if (errno == ENOENT)
  98                                 err = 0;
  99                         break;
 100                 }
 101         }
 102         return err;
 103 }
 104
 105 /* Reset permissions on the device node, before unlinking it to make sure,
 106  * that permissions of possible hard links will be removed too.
 107  */
 108 int util_unlink_secure(struct udev *udev, const char *filename)
 109 {
 110         int err;
 111
 112         chown(filename, 0, 0);
 113         chmod(filename, 0000);
 114         err = unlink(filename);
 115         if (errno == ENOENT)
 116                 err = 0;
 117         if (err)
 118                 err(udev, "unlink(%s) failed: %m\n", filename);
 119         return err;
 120 }
 121
 122 uid_t util_lookup_user(struct udev *udev, const char *user)
 123 {
 124         char *endptr;
 125         int buflen = sysconf(_SC_GETPW_R_SIZE_MAX);
 126         char buf[buflen];
 127         struct passwd pwbuf;
 128         struct passwd *pw;
 129         uid_t uid;
 130
 131         if (strcmp(user, "root") == 0)
 132                 return 0;
 133         uid = strtoul(user, &endptr, 10);
 134         if (endptr[0] == '\0')
 135                 return uid;
 136
 137         errno = getpwnam_r(user, &pwbuf, buf, buflen, &pw);
 138         if (pw != NULL)
 139                 return pw->pw_uid;
 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         return 0;
 145 }
 146
 147 gid_t util_lookup_group(struct udev *udev, const char *group)
 148 {
 149         char *endptr;
 150         int buflen = sysconf(_SC_GETGR_R_SIZE_MAX);
 151         char *buf;
 152         struct group grbuf;
 153         struct group *gr;
 154         gid_t gid = 0;
 155
 156         if (strcmp(group, "root") == 0)
 157                 return 0;
 158         gid = strtoul(group, &endptr, 10);
 159         if (endptr[0] == '\0')
 160                 return gid;
 161         buf = NULL;
 162         gid = 0;
 163         for (;;) {
 164                 char *newbuf;
 165
 166                 newbuf = realloc(buf, buflen);
 167                 if (!newbuf)
 168                         break;
 169                 buf = newbuf;
 170                 errno = getgrnam_r(group, &grbuf, buf, buflen, &gr);
 171                 if (gr != NULL) {
 172                         gid = gr->gr_gid;
 173                 } else if (errno == ERANGE) {
 174                         buflen *= 2;
 175                         continue;
 176                 } else if (errno == 0 || errno == ENOENT || errno == ESRCH) {
 177                         err(udev, "specified group '%s' unknown\n", group);
 178                 } else {
 179                         err(udev, "error resolving group '%s': %m\n", group);
 180                 }
 181                 break;
 182         }
 183         free(buf);
 184         return gid;
 185 }
 186
 187 /* handle "[<SUBSYSTEM>/<KERNEL>]<attribute>" format */
 188 int util_resolve_subsys_kernel(struct udev *udev, const char *string,
 189                                char *result, size_t maxsize, int read_value)
 190 {
 191         char temp[UTIL_PATH_SIZE];
 192         char *subsys;
 193         char *sysname;
 194         struct udev_device *dev;
 195         char *attr;
 196
 197         if (string[0] != '[')
 198                 return -1;
 199
 200         util_strscpy(temp, sizeof(temp), string);
 201
 202         subsys = &temp[1];
 203
 204         sysname = strchr(subsys, '/');
 205         if (sysname == NULL)
 206                 return -1;
 207         sysname[0] = '\0';
 208         sysname = &sysname[1];
 209
 210         attr = strchr(sysname, ']');
 211         if (attr == NULL)
 212                 return -1;
 213         attr[0] = '\0';
 214         attr = &attr[1];
 215         if (attr[0] == '/')
 216                 attr = &attr[1];
 217         if (attr[0] == '\0')
 218                 attr = NULL;
 219
 220         if (read_value && attr == NULL)
 221                 return -1;
 222
 223         dev = udev_device_new_from_subsystem_sysname(udev, subsys, sysname);
 224         if (dev == NULL)
 225                 return -1;
 226
 227         if (read_value) {
 228                 const char *val;
 229
 230                 val = udev_device_get_sysattr_value(dev, attr);
 231                 if (val != NULL)
 232                         util_strscpy(result, maxsize, val);
 233                 else
 234                         result[0] = '\0';
 235                 info(udev, "value '[%s/%s]%s' is '%s'\n", subsys, sysname, attr, result);
 236         } else {
 237                 size_t l;
 238                 char *s;
 239
 240                 s = result;
 241                 l = util_strpcpyl(&s, maxsize, udev_device_get_syspath(dev), NULL);
 242                 if (attr != NULL)
 243                         util_strpcpyl(&s, l, "/", attr, NULL);
 244                 info(udev, "path '[%s/%s]%s' is '%s'\n", subsys, sysname, attr, result);
 245         }
 246         udev_device_unref(dev);
 247         return 0;
 248 }
 249
 250 int util_run_program(struct udev *udev, const char *command, char **envp,
 251                      char *result, size_t ressize, size_t *reslen,
 252                      const sigset_t *sigmask, bool reset_prio)
 253 {
 254         int status;
 255         int outpipe[2] = {-1, -1};
 256         int errpipe[2] = {-1, -1};
 257         pid_t pid;
 258         char arg[UTIL_PATH_SIZE];
 259         char program[UTIL_PATH_SIZE];
 260         char *argv[((sizeof(arg) + 1) / 2) + 1];
 261         int devnull;
 262         int i;
 263         int err = 0;
 264
 265         info(udev, "'%s' started\n", command);
 266
 267         /* build argv from command */
 268         util_strscpy(arg, sizeof(arg), command);
 269         i = 0;
 270         if (strchr(arg, ' ') != NULL) {
 271                 char *pos = arg;
 272
 273                 while (pos != NULL && pos[0] != '\0') {
 274                         if (pos[0] == '\'') {
 275                                 /* do not separate quotes */
 276                                 pos++;
 277                                 argv[i] = strsep(&pos, "\'");
 278                                 if (pos != NULL)
 279                                         while (pos[0] == ' ')
 280                                                 pos++;
 281                         } else {
 282                                 argv[i] = strsep(&pos, " ");
 283                                 if (pos != NULL)
 284                                         while (pos[0] == ' ')
 285                                                 pos++;
 286                         }
 287                         dbg(udev, "arg[%i] '%s'\n", i, argv[i]);
 288                         i++;
 289                 }
 290                 argv[i] = NULL;
 291         } else {
 292                 argv[0] = arg;
 293                 argv[1] = NULL;
 294         }
 295
 296         /* prepare pipes from child to parent */
 297         if (result != NULL || udev_get_log_priority(udev) >= LOG_INFO) {
 298                 if (pipe(outpipe) != 0) {
 299                         err(udev, "pipe failed: %m\n");
 300                         return -1;
 301                 }
 302         }
 303         if (udev_get_log_priority(udev) >= LOG_INFO) {
 304                 if (pipe(errpipe) != 0) {
 305                         err(udev, "pipe failed: %m\n");
 306                         return -1;
 307                 }
 308         }
 309
 310         /* allow programs in /lib/udev/ to be called without the path */
 311         if (argv[0][0] != '/') {
 312                 util_strscpyl(program, sizeof(program), LIBEXECDIR "/", argv[0], NULL);
 313                 argv[0] = program;
 314         }
 315
 316         pid = fork();
 317         switch(pid) {
 318         case 0:
 319                 /* child closes parent ends of pipes */
 320                 if (outpipe[READ_END] > 0)
 321                         close(outpipe[READ_END]);
 322                 if (errpipe[READ_END] > 0)
 323                         close(errpipe[READ_END]);
 324
 325                 /* discard child output or connect to pipe */
 326                 devnull = open("/dev/null", O_RDWR);
 327                 if (devnull > 0) {
 328                         dup2(devnull, STDIN_FILENO);
 329                         if (outpipe[WRITE_END] < 0)
 330                                 dup2(devnull, STDOUT_FILENO);
 331                         if (errpipe[WRITE_END] < 0)
 332                                 dup2(devnull, STDERR_FILENO);
 333                         close(devnull);
 334                 } else
 335                         err(udev, "open /dev/null failed: %m\n");
 336                 if (outpipe[WRITE_END] > 0) {
 337                         dup2(outpipe[WRITE_END], STDOUT_FILENO);
 338                         close(outpipe[WRITE_END]);
 339                 }
 340                 if (errpipe[WRITE_END] > 0) {
 341                         dup2(errpipe[WRITE_END], STDERR_FILENO);
 342                         close(errpipe[WRITE_END]);
 343                 }
 344
 345                 if (sigmask)
 346                         sigprocmask(SIG_SETMASK, sigmask, NULL);
 347                 if (reset_prio)
 348                         setpriority(PRIO_PROCESS, 0, 0);
 349
 350                 execve(argv[0], argv, envp);
 351                 if (errno == ENOENT || errno == ENOTDIR) {
 352                         /* may be on a filesystem which is not mounted right now */
 353                         info(udev, "program '%s' not found\n", argv[0]);
 354                 } else {
 355                         /* other problems */
 356                         err(udev, "exec of program '%s' failed\n", argv[0]);
 357                 }
 358                 _exit(1);
 359         case -1:
 360                 err(udev, "fork of '%s' failed: %m\n", argv[0]);
 361                 return -1;
 362         default:
 363                 /* read from child if requested */
 364                 if (outpipe[READ_END] > 0 || errpipe[READ_END] > 0) {
 365                         ssize_t count;
 366                         size_t respos = 0;
 367
 368                         /* parent closes child ends of pipes */
 369                         if (outpipe[WRITE_END] > 0)
 370                                 close(outpipe[WRITE_END]);
 371                         if (errpipe[WRITE_END] > 0)
 372                                 close(errpipe[WRITE_END]);
 373
 374                         /* read child output */
 375                         while (outpipe[READ_END] > 0 || errpipe[READ_END] > 0) {
 376                                 int fdcount;
 377                                 fd_set readfds;
 378
 379                                 FD_ZERO(&readfds);
 380                                 if (outpipe[READ_END] > 0)
 381                                         FD_SET(outpipe[READ_END], &readfds);
 382                                 if (errpipe[READ_END] > 0)
 383                                         FD_SET(errpipe[READ_END], &readfds);
 384                                 fdcount = select(MAX(outpipe[READ_END], errpipe[READ_END])+1, &readfds, NULL, NULL, NULL);
 385                                 if (fdcount < 0) {
 386                                         if (errno == EINTR)
 387                                                 continue;
 388                                         err = -1;
 389                                         break;
 390                                 }
 391
 392                                 /* get stdout */
 393                                 if (outpipe[READ_END] > 0 && FD_ISSET(outpipe[READ_END], &readfds)) {
 394                                         char inbuf[1024];
 395                                         char *pos;
 396                                         char *line;
 397
 398                                         count = read(outpipe[READ_END], inbuf, sizeof(inbuf)-1);
 399                                         if (count <= 0) {
 400                                                 close(outpipe[READ_END]);
 401                                                 outpipe[READ_END] = -1;
 402                                                 if (count < 0) {
 403                                                         err(udev, "stdin read failed: %m\n");
 404                                                         err = -1;
 405                                                 }
 406                                                 continue;
 407                                         }
 408                                         inbuf[count] = '\0';
 409
 410                                         /* store result for rule processing */
 411                                         if (result) {
 412                                                 if (respos + count < ressize) {
 413                                                         memcpy(&result[respos], inbuf, count);
 414                                                         respos += count;
 415                                                 } else {
 416                                                         err(udev, "ressize %ld too short\n", (long)ressize);
 417                                                         err = -1;
 418                                                 }
 419                                         }
 420                                         pos = inbuf;
 421                                         while ((line = strsep(&pos, "\n")))
 422                                                 if (pos || line[0] != '\0')
 423                                                         info(udev, "'%s' (stdout) '%s'\n", argv[0], line);
 424                                 }
 425
 426                                 /* get stderr */
 427                                 if (errpipe[READ_END] > 0 && FD_ISSET(errpipe[READ_END], &readfds)) {
 428                                         char errbuf[1024];
 429                                         char *pos;
 430                                         char *line;
 431
 432                                         count = read(errpipe[READ_END], errbuf, sizeof(errbuf)-1);
 433                                         if (count <= 0) {
 434                                                 close(errpipe[READ_END]);
 435                                                 errpipe[READ_END] = -1;
 436                                                 if (count < 0)
 437                                                         err(udev, "stderr read failed: %m\n");
 438                                                 continue;
 439                                         }
 440                                         errbuf[count] = '\0';
 441                                         pos = errbuf;
 442                                         while ((line = strsep(&pos, "\n")))
 443                                                 if (pos || line[0] != '\0')
 444                                                         info(udev, "'%s' (stderr) '%s'\n", argv[0], line);
 445                                 }
 446                         }
 447                         if (outpipe[READ_END] > 0)
 448                                 close(outpipe[READ_END]);
 449                         if (errpipe[READ_END] > 0)
 450                                 close(errpipe[READ_END]);
 451
 452                         /* return the child's stdout string */
 453                         if (result) {
 454                                 result[respos] = '\0';
 455                                 dbg(udev, "result='%s'\n", result);
 456                                 if (reslen)
 457                                         *reslen = respos;
 458                         }
 459                 }
 460                 waitpid(pid, &status, 0);
 461                 if (WIFEXITED(status)) {
 462                         info(udev, "'%s' returned with exitcode %i\n", command, WEXITSTATUS(status));
 463                         if (WEXITSTATUS(status) != 0)
 464                                 err = -1;
 465                 } else {
 466                         err(udev, "'%s' unexpected exit with status 0x%04x\n", command, status);
 467                         err = -1;
 468                 }
 469         }
 470         return err;
 471 }