1 /* vi: set sw=4 ts=4: */
5 * usually setuid root, -c option only works if getuid() == geteuid()
7 * Copyright 1994 Matthew Dillon (dillon@apollo.west.oic.com)
8 * Vladimir Oleynik <dzo@simtreas.ru> (C) 2002
10 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
12 //config:config CRONTAB
13 //config: bool "crontab (9.7 kb)"
16 //config: Crontab manipulates the crontab for a particular user. Only
17 //config: the superuser may specify a different user and/or crontab directory.
18 //config: Note that busybox binary must be setuid root for this applet to
19 //config: work properly.
21 /* Needs to be run by root or be suid root - needs to change /var/spool/cron* files: */
22 //applet:IF_CRONTAB(APPLET(crontab, BB_DIR_USR_BIN, BB_SUID_REQUIRE))
24 //kbuild:lib-$(CONFIG_CRONTAB) += crontab.o
26 //usage:#define crontab_trivial_usage
27 //usage: "[-c DIR] [-u USER] [-ler]|[FILE]"
28 //usage:#define crontab_full_usage "\n\n"
29 //usage: " -c Crontab directory"
31 //usage: "\n -l List crontab"
32 //usage: "\n -e Edit crontab"
33 //usage: "\n -r Delete crontab"
34 //usage: "\n FILE Replace crontab by FILE ('-': stdin)"
38 #define CRONTABS CONFIG_FEATURE_CROND_DIR "/crontabs"
40 #define CRONUPDATE "cron.update"
43 static void edit_file(const struct passwd *pas, const char *file)
49 if (pid) { /* parent */
54 /* CHILD - change user and run editor */
55 /* initgroups, setgid, setuid */
57 setup_environment(pas->pw_shell,
58 SETUP_ENV_CHANGEENV | SETUP_ENV_TO_TMP,
60 ptr = getenv("VISUAL");
62 ptr = getenv("EDITOR");
67 BB_EXECLP(ptr, ptr, file, NULL);
68 bb_perror_msg_and_die("can't execute '%s'", ptr);
71 int crontab_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
72 int crontab_main(int argc UNUSED_PARAM, char **argv)
74 const struct passwd *pas;
75 const char *crontab_dir = CRONTABS;
78 char *user_name; /* -u USER */
83 /* file [opts] Replace crontab from file
84 * - [opts] Replace crontab from stdin
86 * -c dir Crontab directory
87 * -l List crontab for user
88 * -e Edit crontab for user
89 * -r Delete crontab for user
90 * bbox also supports -d == -r, but most other crontab
91 * implementations do not. Deprecated.
99 OPT_ler = OPT_l + OPT_e + OPT_r,
102 opt_ler = getopt32(argv, "^" "u:c:lerd" "\0" "?1:dr"/*max one arg; -d implies -r*/,
103 &user_name, &crontab_dir
107 if (sanitize_env_if_suid()) { /* Clears dangerous stuff, sets PATH */
108 /* Run by non-root */
109 if (opt_ler & (OPT_u|OPT_c))
110 bb_error_msg_and_die(bb_msg_you_must_be_root);
113 if (opt_ler & OPT_u) {
114 pas = xgetpwnam(user_name);
116 pas = xgetpwuid(getuid());
119 #define user_name DONT_USE_ME_BEYOND_THIS_POINT
121 /* From now on, keep only -l, -e, -r bits */
123 if ((opt_ler - 1) & opt_ler) /* more than one bit set? */
126 /* Read replacement file under user's UID/GID/group vector */
127 src_fd = STDIN_FILENO;
128 if (!opt_ler) { /* Replace? */
131 if (NOT_LONE_DASH(argv[0])) {
132 src_fd = xopen_as_uid_gid(argv[0], O_RDONLY, pas->pw_uid, pas->pw_gid);
136 /* cd to our crontab directory */
141 /* Handle requested operation */
144 default: /* case OPT_r: Delete */
145 unlink(pas->pw_name);
148 case OPT_l: /* List */
150 char *args[2] = { pas->pw_name, NULL };
153 * the rest go play with cron update file */
156 case OPT_e: /* Edit */
157 tmp_fname = xasprintf("%s.%u", crontab_dir, (unsigned)getpid());
158 /* No O_EXCL: we don't want to be stuck if earlier crontabs
159 * were killed, leaving stale temp file behind */
160 src_fd = xopen3(tmp_fname, O_RDWR|O_CREAT|O_TRUNC, 0600);
161 fchown(src_fd, pas->pw_uid, pas->pw_gid);
162 fd = open(pas->pw_name, O_RDONLY);
164 bb_copyfd_eof(fd, src_fd);
166 xlseek(src_fd, 0, SEEK_SET);
168 close_on_exec_on(src_fd); /* don't want editor to see this fd */
169 edit_file(pas, tmp_fname);
172 case 0: /* Replace (no -l, -e, or -r were given) */
173 new_fname = xasprintf("%s.new", pas->pw_name);
174 fd = open(new_fname, O_WRONLY|O_CREAT|O_TRUNC|O_APPEND, 0600);
176 bb_copyfd_eof(src_fd, fd);
178 xrename(new_fname, pas->pw_name);
180 bb_error_msg("can't create %s/%s",
181 crontab_dir, new_fname);
189 /* Bump notification file. Handle window where crond picks file up
190 * before we can write our entry out.
192 while ((fd = open(CRONUPDATE, O_WRONLY|O_CREAT|O_APPEND, 0600)) >= 0) {
195 fdprintf(fd, "%s\n", pas->pw_name);
196 if (fstat(fd, &st) != 0 || st.st_nlink != 0) {
201 * file was deleted, maybe crond missed our notification */
206 bb_error_msg("can't append to %s/%s",
207 crontab_dir, CRONUPDATE);