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utils-std

Collection of commonly available Unix tools git clone https://anongit.hacktivis.me/git/utils-std.git

chown.c (7185B)

    

  1. // utils-std: Collection of commonly available Unix tools
  2. // SPDX-FileCopyrightText: 2017 Haelwenn (lanodan) Monnier <contact+utils@hacktivis.me>
  3. // SPDX-License-Identifier: MPL-2.0
  5. #define _POSIX_C_SOURCE 200809L
  7. // NetBSD <10 hides fdopendir behind _NETBSD_SOURCE
  8. #if __NetBSD_Version__ < 1000000000
  9. #define _NETBSD_SOURCE
  10. #endif
  12. #include "../lib/fs.h"
  13. #include "../lib/user_group_parse.h"
  15. #include <assert.h>
  16. #include <dirent.h> // fdopendir, readdir, closedir
  17. #include <errno.h>
  18. #include <fcntl.h>  // AT_FDCWD, fchownat
  19. #include <limits.h> // PATH_MAX
  20. #include <stdbool.h>
  21. #include <stdio.h>    // fprintf
  22. #include <stdlib.h>   // abort, exit
  23. #include <string.h>   // strerror, strcmp
  24. #include <sys/stat.h> // fstatat, S_ISDIR
  25. #include <unistd.h>   // getopt
  26. #ifdef HAS_GETOPT_LONG
  27. #include <getopt.h>
  28. #endif
  30. const char *argv0 = NULL;
  32. static uid_t user = (uid_t)-1;
  33. static uid_t group = (uid_t)-1;
  35. static bool opt_v = false, opt_R = false;
  37. enum chown_follow_symlinks
  38. {
  39. 	CHOWN_FOLLOW_UNK_SYMLINKS,
  40. 	CHOWN_FOLLOW_ALL_SYMLINKS,
  41. 	CHOWN_FOLLOW_NO_SYMLINK,
  42. 	CHOWN_FOLLOW_ONE_SYMLINK,
  43. };
  45. static int
  46. do_fchownat(int fd, char *name, char *acc_path, enum chown_follow_symlinks follow_symlinks)
  47. {
  48. 	struct stat stats;
  49. 	int err = 0;
  51. 	int stat_opts = (follow_symlinks == CHOWN_FOLLOW_NO_SYMLINK) ? AT_SYMLINK_NOFOLLOW : 0;
  52. 	int chown_opts = (follow_symlinks == CHOWN_FOLLOW_NO_SYMLINK) ? AT_SYMLINK_NOFOLLOW : 0;
  54. 	assert(errno == 0);
  55. 	if(fstatat(fd, name, &stats, stat_opts) != 0)
  56. 	{
  57. 		fprintf(stderr,
  58. 		        "%s: error: Failed getting status for '%s': %s\n",
  59. 		        argv0,
  60. 		        acc_path,
  61. 		        strerror(errno));
  62. 		errno = 0;
  63. 		return 1;
  64. 	}
  66. 	bool change = false;
  67. 	if(user != (uid_t)-1 && stats.st_uid != user) change = true;
  68. 	if(group != (uid_t)-1 && stats.st_gid != group) change = true;
  70. 	if(change)
  71. 	{
  72. 		assert(errno == 0);
  73. 		if(fchownat(fd, name, user, group, chown_opts) != 0)
  74. 		{
  75. 			fprintf(stderr,
  76. 			        "%s: error: Failed setting ownership to '%d:%d' for '%s': %s\n",
  77. 			        argv0,
  78. 			        user,
  79. 			        group,
  80. 			        acc_path,
  81. 			        strerror(errno));
  82. 			errno = 0;
  83. 			return 1;
  84. 		}
  86. 		if(opt_v)
  87. 			printf("%s: Ownership changed from %d:%d to %d:%d for '%s'\n",
  88. 			       argv0,
  89. 			       stats.st_uid,
  90. 			       stats.st_gid,
  91. 			       user,
  92. 			       group,
  93. 			       acc_path);
  94. 	}
  95. 	else
  96. 	{
  97. 		if(opt_v)
  98. 			printf("%s: Ownership already set to %d:%d for '%s'\n",
  99. 			       argv0,
  100. 			       stats.st_uid,
  101. 			       stats.st_gid,
  102. 			       acc_path);
  103. 	}
  105. 	if(opt_R && S_ISDIR(stats.st_mode))
  106. 	{
  107. 		assert(errno == 0);
  108. 		int dir = openat(fd, name, O_RDONLY | O_DIRECTORY | O_CLOEXEC);
  109. 		if(dir == -1)
  110. 		{
  111. 			fprintf(stderr,
  112. 			        "%s: error: Couldn't open '%s' as directory: %s\n",
  113. 			        argv0,
  114. 			        acc_path,
  115. 			        strerror(errno));
  116. 			errno = 0;
  117. 			return 1;
  118. 		}
  120. 		assert(errno == 0);
  121. 		DIR *dirp = fdopendir(dir);
  122. 		if(dirp == NULL)
  123. 		{
  124. 			fprintf(stderr,
  125. 			        "%s: error: Couldn't get DIR entry for opened '%s': %s\n",
  126. 			        argv0,
  127. 			        acc_path,
  128. 			        strerror(errno));
  129. 			errno = 0;
  130. 			return 1;
  131. 		}
  133. 		while(true)
  134. 		{
  135. 			assert(errno == 0);
  136. 			struct dirent *dp = readdir(dirp);
  137. 			if(dp == NULL)
  138. 			{
  139. 				if(errno == 0) break;
  141. 				fprintf(stderr,
  142. 				        "%s: error: Failed reading directory '%s': %s\n",
  143. 				        argv0,
  144. 				        acc_path,
  145. 				        strerror(errno));
  146. 				closedir(dirp); // FIXME: unhandled error
  147. 				errno = 0;
  148. 				return 1;
  149. 			}
  151. 			if(strcmp(dp->d_name, ".") == 0) continue;
  152. 			if(strcmp(dp->d_name, "..") == 0) continue;
  154. 			assert(errno == 0);
  155. 			char new_path[PATH_MAX] = "";
  156. 			if(snprintf(new_path, PATH_MAX, "%s/%s", acc_path, dp->d_name) < 0)
  157. 			{
  158. 				fprintf(stderr,
  159. 				        "%s: error: Couldn't concatenate '%s' into parent '%s', skipping to next entry: %s",
  160. 				        argv0,
  161. 				        name,
  162. 				        acc_path,
  163. 				        strerror(errno));
  164. 				err++;
  165. 				errno = 0;
  166. 				continue;
  167. 			}
  169. 			enum chown_follow_symlinks child_follow_symlinks =
  170. 			    (follow_symlinks == CHOWN_FOLLOW_ONE_SYMLINK) ? CHOWN_FOLLOW_NO_SYMLINK : follow_symlinks;
  172. 			// No depth counter for now, unlikely to be a problem as symlinks aren't followed
  173. 			int ret = do_fchownat(dir, dp->d_name, new_path, child_follow_symlinks);
  174. 			if(ret != 0) return ret;
  175. 		}
  177. 		// fdopendir allocates memory for DIR, needs closedir
  178. 		assert(errno == 0);
  179. 		if(closedir(dirp) != 0)
  180. 		{
  181. 			fprintf(stderr,
  182. 			        "%s: error: Deallocating directory entry for '%s' failed: %s\n",
  183. 			        argv0,
  184. 			        acc_path,
  185. 			        strerror(errno));
  186. 			errno = 0;
  187. 			return 1;
  188. 		}
  189. 	}
  191. 	return err;
  192. }
  194. static void
  195. usage(void)
  196. {
  197. 	if(strcmp(argv0, "chown") == 0)
  198. 		fprintf(stderr, "Usage: %s [-h | -R [-H|-L|-P]] owner[:group] file...\n", argv0);
  199. 	else if(strcmp(argv0, "chgrp") == 0)
  200. 		fprintf(stderr, "Usage: %s [-h | -R [-H|-L|-P]] group file...\n", argv0);
  201. 	else
  202. 	{
  203. 		fprintf(
  204. 		    stderr, "%s: error: Unknown utility '%s' expected either chown or chgrp\n", argv0, argv0);
  205. 		exit(1);
  206. 	}
  207. }
  209. int
  210. main(int argc, char *argv[])
  211. {
  212. 	argv0 = static_basename(argv[0]);
  214. 	enum chown_follow_symlinks follow_symlinks = CHOWN_FOLLOW_UNK_SYMLINKS;
  216. 	int c = -1;
  217. #ifdef HAS_GETOPT_LONG
  218. 	// Strictly for GNUisms compatibility so no long-only options
  219. 	// clang-format off
  220. 	static struct option opts[] = {
  221. 		{"no-dereference", no_argument, 0, 'h'},
  222. 		{"recursive", no_argument, 0, 'R'},
  223. 		{"verbose", no_argument, 0, 'v'},
  224. 		{0, 0, 0, 0},
  225. 	};
  226. 	// clang-format on
  228. 	// Need + as first character to get POSIX-style option parsing
  229. 	while((c = getopt_long(argc, argv, "+:hRHLPv", opts, NULL)) != -1)
  230. #else
  231. 	while((c = getopt(argc, argv, ":hRHLPv")) != -1)
  232. #endif
  233. 	{
  234. 		switch(c)
  235. 		{
  236. 		case 'h':
  237. 			follow_symlinks = CHOWN_FOLLOW_NO_SYMLINK;
  238. 			break;
  239. 		case 'R':
  240. 			opt_R = true;
  241. 			break;
  242. 		case 'H':
  243. 			follow_symlinks = CHOWN_FOLLOW_ONE_SYMLINK;
  244. 			break;
  245. 		case 'L':
  246. 			follow_symlinks = CHOWN_FOLLOW_ALL_SYMLINKS;
  247. 			break;
  248. 		case 'P':
  249. 			follow_symlinks = CHOWN_FOLLOW_NO_SYMLINK;
  250. 			break;
  251. 		case 'v':
  252. 			opt_v = true;
  253. 			break;
  254. 		case ':':
  255. 			fprintf(stderr, "%s: error: Missing operand for option: '-%c'\n", argv0, optopt);
  256. 			usage();
  257. 			return 1;
  258. 		case '?':
  259. 			fprintf(stderr, "%s: error: Unrecognised option: '-%c'\n", argv0, optopt);
  260. 			usage();
  261. 			return 1;
  262. 		default:
  263. 			abort();
  264. 		}
  265. 	}
  267. 	argc -= optind;
  268. 	argv += optind;
  270. 	if(follow_symlinks == CHOWN_FOLLOW_UNK_SYMLINKS)
  271. 		follow_symlinks = opt_R ? CHOWN_FOLLOW_NO_SYMLINK : CHOWN_FOLLOW_ALL_SYMLINKS;
  273. 	if(argc < 2)
  274. 	{
  275. 		fprintf(stderr, "%s: error: Expects >=2 arguments, %d given\n", argv0, argc);
  276. 		usage();
  277. 		return 1;
  278. 	}
  280. 	if(strcmp(argv0, "chown") == 0)
  281. 	{
  282. 		char *gname = strchr(argv[0], ':');
  283. 		if(gname != NULL)
  284. 		{
  285. 			gname[0] = 0;
  286. 			gname++;
  288. 			if(parse_group(gname, &group) < 0) return 1;
  289. 		}
  290. 		if(parse_user(argv[0], &user) < 0) return 1;
  291. 	}
  292. 	else if(strcmp(argv0, "chgrp") == 0)
  293. 	{
  294. 		if(parse_group(argv[0], &group) < 0) return 1;
  295. 	}
  296. 	else
  297. 	{
  298. 		fprintf(
  299. 		    stderr, "%s: error: Unknown utility '%s' expected either chown or chgrp\n", argv0, argv0);
  300. 		return 1;
  301. 	}
  303. 	for(int i = 1; i < argc; i++)
  304. 	{
  305. 		int ret = do_fchownat(AT_FDCWD, argv[i], argv[i], follow_symlinks);
  306. 		if(ret != 0) return ret;
  307. 	}
  309. 	return 0;
  310. }