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utils-std

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

chown.c (7010B)

    

  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 <dirent.h> // fdopendir, readdir, closedir
  16. #include <errno.h>
  17. #include <fcntl.h>  // AT_FDCWD, fchownat
  18. #include <limits.h> // PATH_MAX
  19. #include <stdbool.h>
  20. #include <stdio.h>    // fprintf
  21. #include <stdlib.h>   // abort, exit
  22. #include <string.h>   // strerror, strcmp
  23. #include <sys/stat.h> // fstatat, S_ISDIR
  24. #include <unistd.h>   // getopt
  25. #ifdef HAS_GETOPT_LONG
  26. #include <getopt.h>
  27. #endif
  29. const char *argv0 = NULL;
  31. static uid_t user = (uid_t)-1;
  32. static uid_t group = (uid_t)-1;
  34. static bool opt_v = false, opt_R = false;
  36. enum chown_follow_symlinks
  37. {
  38. 	CHOWN_FOLLOW_UNK_SYMLINKS,
  39. 	CHOWN_FOLLOW_ALL_SYMLINKS,
  40. 	CHOWN_FOLLOW_NO_SYMLINK,
  41. 	CHOWN_FOLLOW_ONE_SYMLINK,
  42. };
  44. static int
  45. do_fchownat(int fd, char *name, char *acc_path, enum chown_follow_symlinks follow_symlinks)
  46. {
  47. 	struct stat stats;
  48. 	int err = 0;
  50. 	int stat_opts = (follow_symlinks == CHOWN_FOLLOW_NO_SYMLINK) ? AT_SYMLINK_NOFOLLOW : 0;
  51. 	int chown_opts = (follow_symlinks == CHOWN_FOLLOW_NO_SYMLINK) ? AT_SYMLINK_NOFOLLOW : 0;
  53. 	if(fstatat(fd, name, &stats, stat_opts) != 0)
  54. 	{
  55. 		fprintf(stderr,
  56. 		        "%s: error: Failed getting status for '%s': %s\n",
  57. 		        argv0,
  58. 		        acc_path,
  59. 		        strerror(errno));
  60. 		errno = 0;
  61. 		return 1;
  62. 	}
  64. 	bool change = false;
  65. 	if(user != (uid_t)-1 && stats.st_uid != user) change = true;
  66. 	if(group != (uid_t)-1 && stats.st_gid != group) change = true;
  68. 	if(change)
  69. 	{
  70. 		if(fchownat(fd, name, user, group, chown_opts) != 0)
  71. 		{
  72. 			fprintf(stderr,
  73. 			        "%s: error: Failed setting ownership to '%d:%d' for '%s': %s\n",
  74. 			        argv0,
  75. 			        user,
  76. 			        group,
  77. 			        acc_path,
  78. 			        strerror(errno));
  79. 			errno = 0;
  80. 			return 1;
  81. 		}
  83. 		if(opt_v)
  84. 			printf("%s: Ownership changed from %d:%d to %d:%d for '%s'\n",
  85. 			       argv0,
  86. 			       stats.st_uid,
  87. 			       stats.st_gid,
  88. 			       user,
  89. 			       group,
  90. 			       acc_path);
  91. 	}
  92. 	else
  93. 	{
  94. 		if(opt_v)
  95. 			printf("%s: Ownership already set to %d:%d for '%s'\n",
  96. 			       argv0,
  97. 			       stats.st_uid,
  98. 			       stats.st_gid,
  99. 			       acc_path);
  100. 	}
  102. 	if(opt_R && S_ISDIR(stats.st_mode))
  103. 	{
  104. 		int dir = openat(fd, name, O_RDONLY | O_DIRECTORY | O_CLOEXEC);
  105. 		if(dir == -1)
  106. 		{
  107. 			fprintf(stderr,
  108. 			        "%s: error: Couldn't open '%s' as directory: %s\n",
  109. 			        argv0,
  110. 			        acc_path,
  111. 			        strerror(errno));
  112. 			errno = 0;
  113. 			return 1;
  114. 		}
  116. 		DIR *dirp = fdopendir(dir);
  117. 		if(dirp == NULL)
  118. 		{
  119. 			fprintf(stderr,
  120. 			        "%s: error: Couldn't get DIR entry for opened '%s': %s\n",
  121. 			        argv0,
  122. 			        acc_path,
  123. 			        strerror(errno));
  124. 			errno = 0;
  125. 			return 1;
  126. 		}
  128. 		while(true)
  129. 		{
  130. 			struct dirent *dp = readdir(dirp);
  131. 			if(dp == NULL)
  132. 			{
  133. 				if(errno == 0) break;
  135. 				fprintf(stderr,
  136. 				        "%s: error: Failed reading directory '%s': %s\n",
  137. 				        argv0,
  138. 				        acc_path,
  139. 				        strerror(errno));
  140. 				closedir(dirp); // FIXME: unhandled error
  141. 				errno = 0;
  142. 				return 1;
  143. 			}
  145. 			if(strcmp(dp->d_name, ".") == 0) continue;
  146. 			if(strcmp(dp->d_name, "..") == 0) continue;
  148. 			char new_path[PATH_MAX] = "";
  149. 			if(snprintf(new_path, PATH_MAX, "%s/%s", acc_path, dp->d_name) < 0)
  150. 			{
  151. 				fprintf(stderr,
  152. 				        "%s: error: Couldn't concatenate '%s' into parent '%s', skipping to next entry: %s",
  153. 				        argv0,
  154. 				        name,
  155. 				        acc_path,
  156. 				        strerror(errno));
  157. 				err++;
  158. 				errno = 0;
  159. 				continue;
  160. 			}
  162. 			enum chown_follow_symlinks child_follow_symlinks =
  163. 			    (follow_symlinks == CHOWN_FOLLOW_ONE_SYMLINK) ? CHOWN_FOLLOW_NO_SYMLINK : follow_symlinks;
  165. 			// No depth counter for now, unlikely to be a problem as symlinks aren't followed
  166. 			int ret = do_fchownat(dir, dp->d_name, new_path, child_follow_symlinks);
  167. 			if(ret != 0) return ret;
  168. 		}
  170. 		// fdopendir allocates memory for DIR, needs closedir
  171. 		if(closedir(dirp) != 0)
  172. 		{
  173. 			fprintf(stderr,
  174. 			        "%s: error: Deallocating directory entry for '%s' failed: %s\n",
  175. 			        argv0,
  176. 			        acc_path,
  177. 			        strerror(errno));
  178. 			errno = 0;
  179. 			return 1;
  180. 		}
  181. 	}
  183. 	return err;
  184. }
  186. static void
  187. usage(void)
  188. {
  189. 	if(strcmp(argv0, "chown") == 0)
  190. 		fprintf(stderr, "Usage: %s [-h | -R [-H|-L|-P]] owner[:group] file...\n", argv0);
  191. 	else if(strcmp(argv0, "chgrp") == 0)
  192. 		fprintf(stderr, "Usage: %s [-h | -R [-H|-L|-P]] group file...\n", argv0);
  193. 	else
  194. 	{
  195. 		fprintf(
  196. 		    stderr, "%s: error: Unknown utility '%s' expected either chown or chgrp\n", argv0, argv0);
  197. 		exit(1);
  198. 	}
  199. }
  201. int
  202. main(int argc, char *argv[])
  203. {
  204. 	argv0 = static_basename(argv[0]);
  206. 	enum chown_follow_symlinks follow_symlinks = CHOWN_FOLLOW_UNK_SYMLINKS;
  208. 	int c = -1;
  209. #ifdef HAS_GETOPT_LONG
  210. 	// Strictly for GNUisms compatibility so no long-only options
  211. 	// clang-format off
  212. 	static struct option opts[] = {
  213. 		{"no-dereference", no_argument, 0, 'h'},
  214. 		{"recursive", no_argument, 0, 'R'},
  215. 		{"verbose", no_argument, 0, 'v'},
  216. 		{0, 0, 0, 0},
  217. 	};
  218. 	// clang-format on
  220. 	// Need + as first character to get POSIX-style option parsing
  221. 	while((c = getopt_long(argc, argv, "+:hRHLPv", opts, NULL)) != -1)
  222. #else
  223. 	while((c = getopt(argc, argv, ":hRHLPv")) != -1)
  224. #endif
  225. 	{
  226. 		switch(c)
  227. 		{
  228. 		case 'h':
  229. 			follow_symlinks = CHOWN_FOLLOW_NO_SYMLINK;
  230. 			break;
  231. 		case 'R':
  232. 			opt_R = true;
  233. 			break;
  234. 		case 'H':
  235. 			follow_symlinks = CHOWN_FOLLOW_ONE_SYMLINK;
  236. 			break;
  237. 		case 'L':
  238. 			follow_symlinks = CHOWN_FOLLOW_ALL_SYMLINKS;
  239. 			break;
  240. 		case 'P':
  241. 			follow_symlinks = CHOWN_FOLLOW_NO_SYMLINK;
  242. 			break;
  243. 		case 'v':
  244. 			opt_v = true;
  245. 			break;
  246. 		case ':':
  247. 			fprintf(stderr, "%s: error: Missing operand for option: '-%c'\n", argv0, optopt);
  248. 			usage();
  249. 			return 1;
  250. 		case '?':
  251. 			fprintf(stderr, "%s: error: Unrecognised option: '-%c'\n", argv0, optopt);
  252. 			usage();
  253. 			return 1;
  254. 		default:
  255. 			abort();
  256. 		}
  257. 	}
  259. 	argc -= optind;
  260. 	argv += optind;
  262. 	if(follow_symlinks == CHOWN_FOLLOW_UNK_SYMLINKS)
  263. 		follow_symlinks = opt_R ? CHOWN_FOLLOW_NO_SYMLINK : CHOWN_FOLLOW_ALL_SYMLINKS;
  265. 	if(argc < 2)
  266. 	{
  267. 		fprintf(stderr, "%s: error: Expects >=2 arguments, %d given\n", argv0, argc);
  268. 		usage();
  269. 		return 1;
  270. 	}
  272. 	if(strcmp(argv0, "chown") == 0)
  273. 	{
  274. 		char *gname = strchr(argv[0], ':');
  275. 		if(gname != NULL)
  276. 		{
  277. 			gname[0] = 0;
  278. 			gname++;
  280. 			if(parse_group(gname, &group) < 0) return 1;
  281. 		}
  282. 		if(parse_user(argv[0], &user) < 0) return 1;
  283. 	}
  284. 	else if(strcmp(argv0, "chgrp") == 0)
  285. 	{
  286. 		if(parse_group(argv[0], &group) < 0) return 1;
  287. 	}
  288. 	else
  289. 	{
  290. 		fprintf(
  291. 		    stderr, "%s: error: Unknown utility '%s' expected either chown or chgrp\n", argv0, argv0);
  292. 		return 1;
  293. 	}
  295. 	for(int i = 1; i < argc; i++)
  296. 	{
  297. 		int ret = do_fchownat(AT_FDCWD, argv[i], argv[i], follow_symlinks);
  298. 		if(ret != 0) return ret;
  299. 	}
  301. 	return 0;
  302. }