Diff of /trunk/mkinitrd-magellan/busybox/miscutils/crontab.c

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	revision 815 by niro, Sat Sep 1 22:45:15 2007 UTC	revision 816 by niro, Fri Apr 24 18:33:46 2009 UTC
#	Line 10	Line 10
10	* Licensed under the GPL v2 or later, see the file LICENSE in this tarball.	* Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
11	*/	*/
12
13	#include "busybox.h"	#include "libbb.h"
14
15	#ifndef CRONTABS	#ifndef CRONTABS
16	#define CRONTABS        "/var/spool/cron/crontabs"	#define CRONTABS        "/var/spool/cron/crontabs"
17	#endif	#endif
	#ifndef TMPDIR
	#define TMPDIR          "/var/spool/cron"
	#endif
18	#ifndef CRONUPDATE	#ifndef CRONUPDATE
19	#define CRONUPDATE      "cron.update"	#define CRONUPDATE      "cron.update"
20	#endif	#endif
	#ifndef PATH_VI
	#define PATH_VI         "/bin/vi"   /* location of vi */
	#endif
	static const char *CDir = CRONTABS;
21
22	static void EditFile(const char *user, const char *file);	static void change_user(const struct passwd *pas)
	static int GetReplaceStream(const char *user, const char *file);
	static int ChangeUser(const char *user, short dochdir);
	int crontab_main(int ac, char **av)
23	{	{
24	enum { NONE, EDIT, LIST, REPLACE, DELETE } option = NONE;	xsetenv("USER", pas->pw_name);
25	const struct passwd *pas;	xsetenv("HOME", pas->pw_dir);
26	const char *repFile = NULL;	xsetenv("SHELL", DEFAULT_SHELL);
	int repFd = 0;
	int i;
	char caller[256];           /* user that ran program */
	char buf[1024];
	int UserId;
	UserId = getuid();
	pas = getpwuid(UserId);
	if (pas == NULL)
	bb_perror_msg_and_die("getpwuid");
	safe_strncpy(caller, pas->pw_name, sizeof(caller));
	i = 1;
	if (ac > 1) {
	if (LONE_DASH(av[1])) {
	option = REPLACE;
	++i;
	} else if (av[1][0] != '-') {
	option = REPLACE;
	++i;
	repFile = av[1];
	}
	}
	for (; i < ac; ++i) {
	char *ptr = av[i];
27
28	if (*ptr != '-')	/* initgroups, setgid, setuid */
29	break;	change_identity(pas);
	ptr += 2;
30
31	switch (ptr[-1]) {	if (chdir(pas->pw_dir) < 0) {
32	case 'l':	bb_perror_msg("chdir(%s) by %s failed",
33	if (ptr[-1] == 'l')	pas->pw_dir, pas->pw_name);
34	option = LIST;	xchdir("/tmp");
	/* fall through */
	case 'e':
	if (ptr[-1] == 'e')
	option = EDIT;
	/* fall through */
	case 'd':
	if (ptr[-1] == 'd')
	option = DELETE;
	/* fall through */
	case 'u':
	if (i + 1 < ac && av[i+1][0] != '-') {
	++i;
	if (getuid() == geteuid()) {
	pas = getpwnam(av[i]);
	if (pas) {
	UserId = pas->pw_uid;
	} else {
	bb_error_msg_and_die("user %s unknown", av[i]);
	}
	} else {
	bb_error_msg_and_die("only the superuser may specify a user");
	}
	}
	break;
	case 'c':
	if (getuid() == geteuid()) {
	CDir = (*ptr) ? ptr : av[++i];
	} else {
	bb_error_msg_and_die("-c option: superuser only");
	}
	break;
	default:
	i = ac;
	break;
	}
35	}	}
36	if (i != ac || option == NONE)	}
	bb_show_usage();
	/*
	* Get password entry
	*/
	pas = getpwuid(UserId);
	if (pas == NULL)
	bb_perror_msg_and_die("getpwuid");
37
38	/*	static void edit_file(const struct passwd *pas, const char *file)
39	* If there is a replacement file, obtain a secure descriptor to it.	{
40	*/	const char *ptr;
41		int pid = vfork();
42
43	if (repFile) {	if (pid < 0) /* failure */
44	repFd = GetReplaceStream(caller, repFile);	bb_perror_msg_and_die("vfork");
45	if (repFd < 0)	if (pid) { /* parent */
46	bb_error_msg_and_die("cannot read replacement file");	wait4pid(pid);
47		return;
48		}
49
50		/* CHILD - change user and run editor */
51		change_user(pas);
52		ptr = getenv("VISUAL");
53		if (!ptr) {
54		ptr = getenv("EDITOR");
55		if (!ptr)
56		ptr = "vi";
57	}	}
58
59	/*	BB_EXECLP(ptr, ptr, file, NULL);
60	* Change directory to our crontab directory	bb_perror_msg_and_die("exec %s", ptr);
61	*/	}
	xchdir(CDir);
	/*
	* Handle options as appropriate
	*/
62
63	switch (option) {	static int open_as_user(const struct passwd *pas, const char *file)
64	case LIST:	{
65	{	pid_t pid;
66	FILE *fi;	char c;
67
68	fi = fopen(pas->pw_name, "r");	pid = vfork();
69	if (fi) {	if (pid < 0) /* ERROR */
70	while (fgets(buf, sizeof(buf), fi) != NULL)	bb_perror_msg_and_die("vfork");
71	fputs(buf, stdout);	if (pid) { /* PARENT */
72	fclose(fi);	if (wait4pid(pid) == 0) {
73	} else {	/* exitcode 0: child says it can read */
74	bb_error_msg("no crontab for %s", pas->pw_name);	return open(file, O_RDONLY);
	}
75	}	}
76	break;	return -1;
	case EDIT:
	{
	/* FIXME: messy code here! we have file copying helpers for this! */
	FILE *fi;
	int fd;
	int n;
	char tmp[128];
	snprintf(tmp, sizeof(tmp), TMPDIR "/crontab.%d", getpid());
	fd = xopen3(tmp, O_RDWR|O_CREAT|O_TRUNC|O_EXCL, 0600);
	/* race, use fchown */
	chown(tmp, getuid(), getgid());
	fi = fopen(pas->pw_name, "r");
	if (fi) {
	while ((n = fread(buf, 1, sizeof(buf), fi)) > 0)
	full_write(fd, buf, n);
	}
	EditFile(caller, tmp);
	remove(tmp);
	lseek(fd, 0L, SEEK_SET);
	repFd = fd;
	}
	option = REPLACE;
	/* fall through */
	case REPLACE:
	{
	/* same here */
	char path[1024];
	int fd;
	int n;
	snprintf(path, sizeof(path), "%s.new", pas->pw_name);
	fd = open(path, O_CREAT|O_TRUNC|O_APPEND|O_WRONLY, 0600);
	if (fd >= 0) {
	while ((n = read(repFd, buf, sizeof(buf))) > 0) {
	full_write(fd, buf, n);
	}
	close(fd);
	rename(path, pas->pw_name);
	} else {
	bb_error_msg("cannot create %s/%s", CDir, path);
	}
	close(repFd);
	}
	break;
	case DELETE:
	remove(pas->pw_name);
	break;
	case NONE:
	default:
	break;
77	}	}
78
79	/*	/* CHILD */
80	*  Bump notification file.  Handle window where crond picks file up	/* initgroups, setgid, setuid */
81	*  before we can write our entry out.	change_identity(pas);
82	*/	/* We just try to read one byte. If it works, file is readable
83		* under this user. We signal that by exiting with 0. */
84	if (option == REPLACE || option == DELETE) {	_exit(safe_read(xopen(file, O_RDONLY), &c, 1) < 0);
	FILE *fo;
	struct stat st;
	while ((fo = fopen(CRONUPDATE, "a"))) {
	fprintf(fo, "%s\n", pas->pw_name);
	fflush(fo);
	if (fstat(fileno(fo), &st) != 0 || st.st_nlink != 0) {
	fclose(fo);
	break;
	}
	fclose(fo);
	/* loop */
	}
	if (fo == NULL) {
	bb_error_msg("cannot append to %s/%s", CDir, CRONUPDATE);
	}
	}
	return 0;
85	}	}
86
87	static int GetReplaceStream(const char *user, const char *file)	int crontab_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
88		int crontab_main(int argc UNUSED_PARAM, char **argv)
89	{	{
90	int filedes[2];	const struct passwd *pas;
91	int pid;	const char *crontab_dir = CRONTABS;
92		char *tmp_fname;
93		char *new_fname;
94		char *user_name;  /* -u USER */
95	int fd;	int fd;
96	int n;	int src_fd;
97	char buf[1024];	int opt_ler;
98
99	if (pipe(filedes) < 0) {	/* file [opts]     Replace crontab from file
100	perror("pipe");	* - [opts]        Replace crontab from stdin
101	return -1;	* -u user         User
102	}	* -c dir          Crontab directory
103	pid = fork();	* -l              List crontab for user
104	if (pid < 0) {	* -e              Edit crontab for user
105	perror("fork");	* -r              Delete crontab for user
106	return -1;	* bbox also supports -d == -r, but most other crontab
107	}	* implementations do not. Deprecated.
108	if (pid > 0) {	*/
109	/*	enum {
110	* PARENT	OPT_u = (1 << 0),
111	*/	OPT_c = (1 << 1),
112		OPT_l = (1 << 2),
113	close(filedes[1]);	OPT_e = (1 << 3),
114	if (read(filedes[0], buf, 1) != 1) {	OPT_r = (1 << 4),
115	close(filedes[0]);	OPT_ler = OPT_l + OPT_e + OPT_r,
116	filedes[0] = -1;	};
117
118		opt_complementary = "?1:dr"; /* max one argument; -d implies -r */
119		opt_ler = getopt32(argv, "u:c:lerd", &user_name, &crontab_dir);
120		argv += optind;
121
122		if (sanitize_env_if_suid()) { /* Clears dangerous stuff, sets PATH */
123		/* run by non-root? */
124		if (opt_ler & (OPT_u|OPT_c))
125		bb_error_msg_and_die("only root can use -c or -u");
126		}
127
128		if (opt_ler & OPT_u) {
129		pas = getpwnam(user_name);
130		if (!pas)
131		bb_error_msg_and_die("user %s is not known", user_name);
132		} else {
133		/* XXX: xgetpwuid */
134		uid_t my_uid = getuid();
135		pas = getpwuid(my_uid);
136		if (!pas)
137		bb_perror_msg_and_die("unknown uid %d", (int)my_uid);
138		}
139
140		#define user_name DONT_USE_ME_BEYOND_THIS_POINT
141
142		/* From now on, keep only -l, -e, -r bits */
143		opt_ler &= OPT_ler;
144		if ((opt_ler - 1) & opt_ler) /* more than one bit set? */
145		bb_show_usage();
146
147		/* Read replacement file under user's UID/GID/group vector */
148		src_fd = STDIN_FILENO;
149		if (!opt_ler) { /* Replace? */
150		if (!argv[0])
151		bb_show_usage();
152		if (NOT_LONE_DASH(argv[0])) {
153		src_fd = open_as_user(pas, argv[0]);
154		if (src_fd < 0)
155		bb_error_msg_and_die("user %s cannot read %s",
156		pas->pw_name, argv[0]);
157	}	}
	return filedes[0];
158	}	}
159
160	/*	/* cd to our crontab directory */
161	* CHILD	xchdir(crontab_dir);
	*/
162
163	close(filedes[0]);	tmp_fname = NULL;
164
165	if (ChangeUser(user, 0) < 0)	/* Handle requested operation */
166	exit(0);	switch (opt_ler) {
167
168	xfunc_error_retval = 0;	default: /* case OPT_r: Delete */
169	fd = xopen(file, O_RDONLY);	unlink(pas->pw_name);
170	buf[0] = 0;	break;
	write(filedes[1], buf, 1);
	while ((n = read(fd, buf, sizeof(buf))) > 0) {
	write(filedes[1], buf, n);
	}
	exit(0);
	}
	static void EditFile(const char *user, const char *file)
	{
	int pid = fork();
	if (pid == 0) {
	/*
	* CHILD - change user and run editor
	*/
	char *ptr;
	char visual[1024];
	if (ChangeUser(user, 1) < 0)
	exit(0);
	ptr = getenv("VISUAL");
	if (ptr == NULL || strlen(ptr) > 256)
	ptr = PATH_VI;
	snprintf(visual, sizeof(visual), "%s %s", ptr, file);
	execl(DEFAULT_SHELL, DEFAULT_SHELL, "-c", visual, NULL);
	perror("exec");
	exit(0);
	}
	if (pid < 0) {
	/*
	* PARENT - failure
	*/
	bb_perror_msg_and_die("fork");
	}
	wait4(pid, NULL, 0, NULL);
	}
171
172	static int ChangeUser(const char *user, short dochdir)	case OPT_l: /* List */
173	{	{
174	struct passwd *pas;	char *args[2] = { pas->pw_name, NULL };
175		return bb_cat(args);
176		/* list exits,
177		* the rest go play with cron update file */
178		}
179
180		case OPT_e: /* Edit */
181		tmp_fname = xasprintf("%s.%u", crontab_dir, (unsigned)getpid());
182		/* No O_EXCL: we don't want to be stuck if earlier crontabs
183		* were killed, leaving stale temp file behind */
184		src_fd = xopen3(tmp_fname, O_RDWR|O_CREAT|O_TRUNC, 0600);
185		fchown(src_fd, pas->pw_uid, pas->pw_gid);
186		fd = open(pas->pw_name, O_RDONLY);
187		if (fd >= 0) {
188		bb_copyfd_eof(fd, src_fd);
189		close(fd);
190		xlseek(src_fd, 0, SEEK_SET);
191		}
192		close_on_exec_on(src_fd); /* don't want editor to see this fd */
193		edit_file(pas, tmp_fname);
194		/* fall through */
195
196	/*	case 0: /* Replace (no -l, -e, or -r were given) */
197	* Obtain password entry and change privileges	new_fname = xasprintf("%s.new", pas->pw_name);
198	*/	fd = open(new_fname, O_WRONLY|O_CREAT|O_TRUNC|O_APPEND, 0600);
199		if (fd >= 0) {
200		bb_copyfd_eof(src_fd, fd);
201		close(fd);
202		xrename(new_fname, pas->pw_name);
203		} else {
204		bb_error_msg("cannot create %s/%s",
205		crontab_dir, new_fname);
206		}
207		if (tmp_fname)
208		unlink(tmp_fname);
209		/*free(tmp_fname);*/
210		/*free(new_fname);*/
211
212	pas = getpwnam(user);	} /* switch */
	if (pas == NULL) {
	bb_perror_msg_and_die("failed to get uid for %s", user);
	}
	setenv("USER", pas->pw_name, 1);
	setenv("HOME", pas->pw_dir, 1);
	setenv("SHELL", DEFAULT_SHELL, 1);
213
214	/*	/* Bump notification file.  Handle window where crond picks file up
215	* Change running state to the user in question	* before we can write our entry out.
216	*/	*/
217	change_identity(pas);	while ((fd = open(CRONUPDATE, O_WRONLY|O_CREAT|O_APPEND, 0600)) >= 0) {
218		struct stat st;
219
220	if (dochdir) {	fdprintf(fd, "%s\n", pas->pw_name);
221	if (chdir(pas->pw_dir) < 0) {	if (fstat(fd, &st) != 0 || st.st_nlink != 0) {
222	bb_perror_msg("chdir(%s) by %s failed", pas->pw_dir, user);	/*close(fd);*/
223	xchdir(TMPDIR);	break;
224	}	}
225		/* st.st_nlink == 0:
226		* file was deleted, maybe crond missed our notification */
227		close(fd);
228		/* loop */
229		}
230		if (fd < 0) {
231		bb_error_msg("cannot append to %s/%s",
232		crontab_dir, CRONUPDATE);
233	}	}
234	return pas->pw_uid;	return 0;
235	}	}

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