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 retval;
  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         while (1) {
  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                 /* remove if empty */
  96                 retval = rmdir(p);
  97                 if (errno == ENOENT)
  98                         retval = 0;
  99                 if (retval) {
 100                         if (errno == ENOTEMPTY)
 101                                 return 0;
 102                         err(udev, "rmdir(%s) failed: %m\n", p);
 103                         break;
 104                 }
 105                 dbg(udev, "removed '%s'\n", p);
 106         }
 107         return 0;
 108 }
 109
 110 /* Reset permissions on the device node, before unlinking it to make sure,
 111  * that permissions of possible hard links will be removed too.
 112  */
 113 int util_unlink_secure(struct udev *udev, const char *filename)
 114 {
 115         int err;
 116
 117         chown(filename, 0, 0);
 118         chmod(filename, 0000);
 119         err = unlink(filename);
 120         if (errno == ENOENT)
 121                 err = 0;
 122         if (err)
 123                 err(udev, "unlink(%s) failed: %m\n", filename);
 124         return err;
 125 }
 126
 127 uid_t util_lookup_user(struct udev *udev, const char *user)
 128 {
 129         char *endptr;
 130         int buflen = sysconf(_SC_GETPW_R_SIZE_MAX);
 131         char buf[buflen];
 132         struct passwd pwbuf;
 133         struct passwd *pw;
 134         uid_t uid;
 135
 136         if (strcmp(user, "root") == 0)
 137                 return 0;
 138         uid = strtoul(user, &endptr, 10);
 139         if (endptr[0] == '\0')
 140                 return uid;
 141
 142         errno = getpwnam_r(user, &pwbuf, buf, buflen, &pw);
 143         if (pw != NULL)
 144                 return pw->pw_uid;
 145         if (errno == 0 || errno == ENOENT || errno == ESRCH)
 146                 err(udev, "specified user '%s' unknown\n", user);
 147         else
 148                 err(udev, "error resolving user '%s': %m\n", user);
 149         return 0;
 150 }
 151
 152 gid_t util_lookup_group(struct udev *udev, const char *group)
 153 {
 154         char *endptr;
 155         int buflen = sysconf(_SC_GETGR_R_SIZE_MAX);
 156         char *buf;
 157         struct group grbuf;
 158         struct group *gr;
 159         gid_t gid = 0;
 160
 161         if (strcmp(group, "root") == 0)
 162                 return 0;
 163         gid = strtoul(group, &endptr, 10);
 164         if (endptr[0] == '\0')
 165                 return gid;
 166         buf = NULL;
 167         gid = 0;
 168         for (;;) {
 169                 char *newbuf;
 170
 171                 newbuf = realloc(buf, buflen);
 172                 if (!newbuf)
 173                         break;
 174                 buf = newbuf;
 175                 errno = getgrnam_r(group, &grbuf, buf, buflen, &gr);
 176                 if (gr != NULL) {
 177                         gid = gr->gr_gid;
 178                 } else if (errno == ERANGE) {
 179                         buflen *= 2;
 180                         continue;
 181                 } else if (errno == 0 || errno == ENOENT || errno == ESRCH) {
 182                         err(udev, "specified group '%s' unknown\n", group);
 183                 } else {
 184                         err(udev, "error resolving group '%s': %m\n", group);
 185                 }
 186                 break;
 187         }
 188         free(buf);
 189         return gid;
 190 }
 191
 192 /* handle "[<SUBSYSTEM>/<KERNEL>]<attribute>" format */
 193 int util_resolve_subsys_kernel(struct udev *udev, const char *string,
 194                                char *result, size_t maxsize, int read_value)
 195 {
 196         char temp[UTIL_PATH_SIZE];
 197         char *subsys;
 198         char *sysname;
 199         struct udev_device *dev;
 200         char *attr;
 201
 202         if (string[0] != '[')
 203                 return -1;
 204
 205         util_strscpy(temp, sizeof(temp), string);
 206
 207         subsys = &temp[1];
 208
 209         sysname = strchr(subsys, '/');
 210         if (sysname == NULL)
 211                 return -1;
 212         sysname[0] = '\0';
 213         sysname = &sysname[1];
 214
 215         attr = strchr(sysname, ']');
 216         if (attr == NULL)
 217                 return -1;
 218         attr[0] = '\0';
 219         attr = &attr[1];
 220         if (attr[0] == '/')
 221                 attr = &attr[1];
 222         if (attr[0] == '\0')
 223                 attr = NULL;
 224
 225         if (read_value && attr == NULL)
 226                 return -1;
 227
 228         dev = udev_device_new_from_subsystem_sysname(udev, subsys, sysname);
 229         if (dev == NULL)
 230                 return -1;
 231
 232         if (read_value) {
 233                 const char *val;
 234
 235                 val = udev_device_get_sysattr_value(dev, attr);
 236                 if (val != NULL)
 237                         util_strscpy(result, maxsize, val);
 238                 else
 239                         result[0] = '\0';
 240                 info(udev, "value '[%s/%s]%s' is '%s'\n", subsys, sysname, attr, result);
 241         } else {
 242                 size_t l;
 243                 char *s;
 244
 245                 s = result;
 246                 l = util_strpcpyl(&s, maxsize, udev_device_get_syspath(dev), NULL);
 247                 if (attr != NULL)
 248                         util_strpcpyl(&s, l, "/", attr, NULL);
 249                 info(udev, "path '[%s/%s]%s' is '%s'\n", subsys, sysname, attr, result);
 250         }
 251         udev_device_unref(dev);
 252         return 0;
 253 }
 254
 255 int util_run_program(struct udev *udev, const char *command, char **envp,
 256                      char *result, size_t ressize, size_t *reslen,
 257                      const sigset_t *sigmask)
 258 {
 259         int status;
 260         int outpipe[2] = {-1, -1};
 261         int errpipe[2] = {-1, -1};
 262         pid_t pid;
 263         char arg[UTIL_PATH_SIZE];
 264         char program[UTIL_PATH_SIZE];
 265         char *argv[((sizeof(arg) + 1) / 2) + 1];
 266         int devnull;
 267         int i;
 268         int err = 0;
 269
 270         info(udev, "'%s' started\n", command);
 271
 272         /* build argv from command */
 273         util_strscpy(arg, sizeof(arg), command);
 274         i = 0;
 275         if (strchr(arg, ' ') != NULL) {
 276                 char *pos = arg;
 277
 278                 while (pos != NULL && pos[0] != '\0') {
 279                         if (pos[0] == '\'') {
 280                                 /* do not separate quotes */
 281                                 pos++;
 282                                 argv[i] = strsep(&pos, "\'");
 283                                 if (pos != NULL)
 284                                         while (pos[0] == ' ')
 285                                                 pos++;
 286                         } else {
 287                                 argv[i] = strsep(&pos, " ");
 288                                 if (pos != NULL)
 289                                         while (pos[0] == ' ')
 290                                                 pos++;
 291                         }
 292                         dbg(udev, "arg[%i] '%s'\n", i, argv[i]);
 293                         i++;
 294                 }
 295                 argv[i] = NULL;
 296         } else {
 297                 argv[0] = arg;
 298                 argv[1] = NULL;
 299         }
 300
 301         /* prepare pipes from child to parent */
 302         if (result != NULL || udev_get_log_priority(udev) >= LOG_INFO) {
 303                 if (pipe(outpipe) != 0) {
 304                         err(udev, "pipe failed: %m\n");
 305                         return -1;
 306                 }
 307         }
 308         if (udev_get_log_priority(udev) >= LOG_INFO) {
 309                 if (pipe(errpipe) != 0) {
 310                         err(udev, "pipe failed: %m\n");
 311                         return -1;
 312                 }
 313         }
 314
 315         /* allow programs in /lib/udev/ to be called without the path */
 316         if (argv[0][0] != '/') {
 317                 util_strscpyl(program, sizeof(program), LIBEXECDIR "/", argv[0], NULL);
 318                 argv[0] = program;
 319         }
 320
 321         pid = fork();
 322         switch(pid) {
 323         case 0:
 324                 /* child closes parent ends of pipes */
 325                 if (outpipe[READ_END] > 0)
 326                         close(outpipe[READ_END]);
 327                 if (errpipe[READ_END] > 0)
 328                         close(errpipe[READ_END]);
 329
 330                 /* discard child output or connect to pipe */
 331                 devnull = open("/dev/null", O_RDWR);
 332                 if (devnull > 0) {
 333                         dup2(devnull, STDIN_FILENO);
 334                         if (outpipe[WRITE_END] < 0)
 335                                 dup2(devnull, STDOUT_FILENO);
 336                         if (errpipe[WRITE_END] < 0)
 337                                 dup2(devnull, STDERR_FILENO);
 338                         close(devnull);
 339                 } else
 340                         err(udev, "open /dev/null failed: %m\n");
 341                 if (outpipe[WRITE_END] > 0) {
 342                         dup2(outpipe[WRITE_END], STDOUT_FILENO);
 343                         close(outpipe[WRITE_END]);
 344                 }
 345                 if (errpipe[WRITE_END] > 0) {
 346                         dup2(errpipe[WRITE_END], STDERR_FILENO);
 347                         close(errpipe[WRITE_END]);
 348                 }
 349
 350                 if (sigmask)
 351                         sigprocmask(SIG_SETMASK, sigmask, NULL);
 352
 353                 execve(argv[0], argv, envp);
 354                 if (errno == ENOENT || errno == ENOTDIR) {
 355                         /* may be on a filesystem which is not mounted right now */
 356                         info(udev, "program '%s' not found\n", argv[0]);
 357                 } else {
 358                         /* other problems */
 359                         err(udev, "exec of program '%s' failed\n", argv[0]);
 360                 }
 361                 _exit(1);
 362         case -1:
 363                 err(udev, "fork of '%s' failed: %m\n", argv[0]);
 364                 return -1;
 365         default:
 366                 /* read from child if requested */
 367                 if (outpipe[READ_END] > 0 || errpipe[READ_END] > 0) {
 368                         ssize_t count;
 369                         size_t respos = 0;
 370
 371                         /* parent closes child ends of pipes */
 372                         if (outpipe[WRITE_END] > 0)
 373                                 close(outpipe[WRITE_END]);
 374                         if (errpipe[WRITE_END] > 0)
 375                                 close(errpipe[WRITE_END]);
 376
 377                         /* read child output */
 378                         while (outpipe[READ_END] > 0 || errpipe[READ_END] > 0) {
 379                                 int fdcount;
 380                                 fd_set readfds;
 381
 382                                 FD_ZERO(&readfds);
 383                                 if (outpipe[READ_END] > 0)
 384                                         FD_SET(outpipe[READ_END], &readfds);
 385                                 if (errpipe[READ_END] > 0)
 386                                         FD_SET(errpipe[READ_END], &readfds);
 387                                 fdcount = select(MAX(outpipe[READ_END], errpipe[READ_END])+1, &readfds, NULL, NULL, NULL);
 388                                 if (fdcount < 0) {
 389                                         if (errno == EINTR)
 390                                                 continue;
 391                                         err = -1;
 392                                         break;
 393                                 }
 394
 395                                 /* get stdout */
 396                                 if (outpipe[READ_END] > 0 && FD_ISSET(outpipe[READ_END], &readfds)) {
 397                                         char inbuf[1024];
 398                                         char *pos;
 399                                         char *line;
 400
 401                                         count = read(outpipe[READ_END], inbuf, sizeof(inbuf)-1);
 402                                         if (count <= 0) {
 403                                                 close(outpipe[READ_END]);
 404                                                 outpipe[READ_END] = -1;
 405                                                 if (count < 0) {
 406                                                         err(udev, "stdin read failed: %m\n");
 407                                                         err = -1;
 408                                                 }
 409                                                 continue;
 410                                         }
 411                                         inbuf[count] = '\0';
 412
 413                                         /* store result for rule processing */
 414                                         if (result) {
 415                                                 if (respos + count < ressize) {
 416                                                         memcpy(&result[respos], inbuf, count);
 417                                                         respos += count;
 418                                                 } else {
 419                                                         err(udev, "ressize %ld too short\n", (long)ressize);
 420                                                         err = -1;
 421                                                 }
 422                                         }
 423                                         pos = inbuf;
 424                                         while ((line = strsep(&pos, "\n")))
 425                                                 if (pos || line[0] != '\0')
 426                                                         info(udev, "'%s' (stdout) '%s'\n", argv[0], line);
 427                                 }
 428
 429                                 /* get stderr */
 430                                 if (errpipe[READ_END] > 0 && FD_ISSET(errpipe[READ_END], &readfds)) {
 431                                         char errbuf[1024];
 432                                         char *pos;
 433                                         char *line;
 434
 435                                         count = read(errpipe[READ_END], errbuf, sizeof(errbuf)-1);
 436                                         if (count <= 0) {
 437                                                 close(errpipe[READ_END]);
 438                                                 errpipe[READ_END] = -1;
 439                                                 if (count < 0)
 440                                                         err(udev, "stderr read failed: %m\n");
 441                                                 continue;
 442                                         }
 443                                         errbuf[count] = '\0';
 444                                         pos = errbuf;
 445                                         while ((line = strsep(&pos, "\n")))
 446                                                 if (pos || line[0] != '\0')
 447                                                         info(udev, "'%s' (stderr) '%s'\n", argv[0], line);
 448                                 }
 449                         }
 450                         if (outpipe[READ_END] > 0)
 451                                 close(outpipe[READ_END]);
 452                         if (errpipe[READ_END] > 0)
 453                                 close(errpipe[READ_END]);
 454
 455                         /* return the childs stdout string */
 456                         if (result) {
 457                                 result[respos] = '\0';
 458                                 dbg(udev, "result='%s'\n", result);
 459                                 if (reslen)
 460                                         *reslen = respos;
 461                         }
 462                 }
 463                 waitpid(pid, &status, 0);
 464                 if (WIFEXITED(status)) {
 465                         info(udev, "'%s' returned with exitcode %i\n", command, WEXITSTATUS(status));
 466                         if (WEXITSTATUS(status) != 0)
 467                                 err = -1;
 468                 } else {
 469                         err(udev, "'%s' unexpected exit with status 0x%04x\n", command, status);
 470                         err = -1;
 471                 }
 472         }
 473         return err;
 474 }