initgroups.c 2.1 KB

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  1. /*
  2. * initgroups.c - This file is part of the libc-8086/grp package for ELKS,
  3. * Copyright (C) 1995, 1996 Nat Friedman <ndf@linux.mit.edu>.
  4. *
  5. * This library is free software; you can redistribute it and/or
  6. * modify it under the terms of the GNU Library General Public
  7. * License as published by the Free Software Foundation; either
  8. * version 2 of the License, or (at your option) any later version.
  9. *
  10. * This library is distributed in the hope that it will be useful,
  11. * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12. * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  13. * Library General Public License for more details.
  14. *
  15. * You should have received a copy of the GNU Library General Public
  16. * License along with this library; if not, write to the Free
  17. * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  18. *
  19. */
  20. #include <unistd.h>
  21. #include <string.h>
  22. #include <fcntl.h>
  23. #include <paths.h>
  24. #include <stdlib.h>
  25. #include "config.h"
  26. #ifdef __UCLIBC_HAS_THREADS__
  27. #include <pthread.h>
  28. static pthread_mutex_t mylock = PTHREAD_MUTEX_INITIALIZER;
  29. # define LOCK pthread_mutex_lock(&mylock)
  30. # define UNLOCK pthread_mutex_unlock(&mylock);
  31. #else
  32. # define LOCK
  33. # define UNLOCK
  34. #endif
  35. static char *line_buff = NULL;
  36. static char **members = NULL;
  37. int initgroups(__const char *user, gid_t gid)
  38. {
  39. register struct group *group;
  40. gid_t *group_list = NULL;
  41. register char **tmp_mem;
  42. int num_groups;
  43. int grp_fd;
  44. if ((grp_fd = open(_PATH_GROUP, O_RDONLY)) < 0)
  45. return -1;
  46. num_groups = 0;
  47. group_list = (gid_t *) realloc(group_list, 1);
  48. group_list[num_groups] = gid;
  49. LOCK;
  50. while ((group = __getgrent(grp_fd, line_buff, members)) != NULL)
  51. {
  52. if (group->gr_gid != gid);
  53. {
  54. tmp_mem = group->gr_mem;
  55. while (*tmp_mem != NULL) {
  56. if (!strcmp(*tmp_mem, user)) {
  57. num_groups++;
  58. group_list = (gid_t *) realloc(group_list, num_groups *
  59. sizeof(gid_t *));
  60. group_list[num_groups-1] = group->gr_gid;
  61. }
  62. tmp_mem++;
  63. }
  64. }
  65. }
  66. close(grp_fd);
  67. UNLOCK;
  68. return setgroups(num_groups, group_list);
  69. }