initgroups.c 2.0 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 "config.h"
  25. int initgroups(__const char *user, gid_t gid)
  26. {
  27. register struct group *group;
  28. #ifndef GR_DYNAMIC_GROUP_LIST
  29. gid_t group_list[GR_MAX_GROUPS];
  30. #else
  31. gid_t *group_list = NULL;
  32. #endif
  33. register char **tmp_mem;
  34. int num_groups;
  35. int grp_fd;
  36. if ((grp_fd = open(_PATH_GROUP, O_RDONLY)) < 0)
  37. return -1;
  38. num_groups = 0;
  39. #ifdef GR_DYNAMIC_GROUP_LIST
  40. group_list = (gid_t *) realloc(group_list, 1);
  41. #endif
  42. group_list[num_groups] = gid;
  43. #ifndef GR_DYNAMIC_GROUP_LIST
  44. while (num_groups < GR_MAX_GROUPS &&
  45. (group = __getgrent(grp_fd)) != NULL)
  46. #else
  47. while ((group = __getgrent(grp_fd)) != NULL)
  48. #endif
  49. {
  50. if (group->gr_gid != gid);
  51. {
  52. tmp_mem = group->gr_mem;
  53. while (*tmp_mem != NULL) {
  54. if (!strcmp(*tmp_mem, user)) {
  55. num_groups++;
  56. #ifdef GR_DYNAMIC_GROUP_LIST
  57. group_list = (gid_t *) realloc(group_list, num_groups *
  58. sizeof(gid_t *));
  59. #endif
  60. group_list[num_groups-1] = group->gr_gid;
  61. }
  62. tmp_mem++;
  63. }
  64. }
  65. }
  66. close(grp_fd);
  67. return setgroups(num_groups, group_list);
  68. }