Bernhard Reutner-Fischer | d9cf7ac | 2006-04-12 18:39:58 +0000 | [diff] [blame] | 1 | /* vi: set sw=4 ts=4: */ |
Eric Andersen | f6f7bfb | 2002-10-22 12:24:59 +0000 | [diff] [blame] | 2 | /* |
| 3 | * CRONTAB |
| 4 | * |
| 5 | * usually setuid root, -c option only works if getuid() == geteuid() |
| 6 | * |
| 7 | * Copyright 1994 Matthew Dillon (dillon@apollo.west.oic.com) |
Mike Frysinger | f284c76 | 2006-04-16 20:38:26 +0000 | [diff] [blame] | 8 | * Vladimir Oleynik <dzo@simtreas.ru> (C) 2002 |
Eric Andersen | f6f7bfb | 2002-10-22 12:24:59 +0000 | [diff] [blame] | 9 | * |
Denys Vlasenko | 0ef64bd | 2010-08-16 20:14:46 +0200 | [diff] [blame] | 10 | * Licensed under GPLv2 or later, see file LICENSE in this source tree. |
Eric Andersen | f6f7bfb | 2002-10-22 12:24:59 +0000 | [diff] [blame] | 11 | */ |
Denys Vlasenko | fb4da16 | 2016-11-22 23:14:24 +0100 | [diff] [blame] | 12 | //config:config CRONTAB |
Denys Vlasenko | b097a84 | 2018-12-28 03:20:17 +0100 | [diff] [blame] | 13 | //config: bool "crontab (10 kb)" |
Denys Vlasenko | fb4da16 | 2016-11-22 23:14:24 +0100 | [diff] [blame] | 14 | //config: default y |
| 15 | //config: help |
Denys Vlasenko | 72089cf | 2017-07-21 09:50:55 +0200 | [diff] [blame] | 16 | //config: Crontab manipulates the crontab for a particular user. Only |
| 17 | //config: the superuser may specify a different user and/or crontab directory. |
Denys Vlasenko | 68b653b | 2017-07-27 10:53:09 +0200 | [diff] [blame] | 18 | //config: Note that busybox binary must be setuid root for this applet to |
Denys Vlasenko | 72089cf | 2017-07-21 09:50:55 +0200 | [diff] [blame] | 19 | //config: work properly. |
Eric Andersen | f6f7bfb | 2002-10-22 12:24:59 +0000 | [diff] [blame] | 20 | |
Denys Vlasenko | f88e3bf | 2016-11-22 23:54:17 +0100 | [diff] [blame] | 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)) |
| 23 | |
| 24 | //kbuild:lib-$(CONFIG_CRONTAB) += crontab.o |
| 25 | |
Pere Orga | 5bc8c00 | 2011-04-11 03:29:49 +0200 | [diff] [blame] | 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" |
| 30 | //usage: "\n -u User" |
| 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)" |
| 35 | |
Denis Vlasenko | b6adbf1 | 2007-05-26 19:00:18 +0000 | [diff] [blame] | 36 | #include "libbb.h" |
Eric Andersen | f6f7bfb | 2002-10-22 12:24:59 +0000 | [diff] [blame] | 37 | |
Denis Vlasenko | ded5dfe | 2009-02-03 23:59:41 +0000 | [diff] [blame] | 38 | #define CRONTABS CONFIG_FEATURE_CROND_DIR "/crontabs" |
Eric Andersen | f6f7bfb | 2002-10-22 12:24:59 +0000 | [diff] [blame] | 39 | #ifndef CRONUPDATE |
| 40 | #define CRONUPDATE "cron.update" |
| 41 | #endif |
Eric Andersen | f6f7bfb | 2002-10-22 12:24:59 +0000 | [diff] [blame] | 42 | |
Denis Vlasenko | 069e347 | 2008-02-16 13:17:13 +0000 | [diff] [blame] | 43 | static void edit_file(const struct passwd *pas, const char *file) |
| 44 | { |
| 45 | const char *ptr; |
Denys Vlasenko | 681efe2 | 2011-03-08 21:00:36 +0100 | [diff] [blame] | 46 | pid_t pid; |
Denis Vlasenko | 069e347 | 2008-02-16 13:17:13 +0000 | [diff] [blame] | 47 | |
Denys Vlasenko | 681efe2 | 2011-03-08 21:00:36 +0100 | [diff] [blame] | 48 | pid = xvfork(); |
Denis Vlasenko | 069e347 | 2008-02-16 13:17:13 +0000 | [diff] [blame] | 49 | if (pid) { /* parent */ |
| 50 | wait4pid(pid); |
| 51 | return; |
| 52 | } |
| 53 | |
| 54 | /* CHILD - change user and run editor */ |
Bernhard Reutner-Fischer | 99709ab | 2010-02-24 16:10:09 +0100 | [diff] [blame] | 55 | /* initgroups, setgid, setuid */ |
| 56 | change_identity(pas); |
Denys Vlasenko | 681efe2 | 2011-03-08 21:00:36 +0100 | [diff] [blame] | 57 | setup_environment(pas->pw_shell, |
Denys Vlasenko | 931c55f | 2022-01-13 12:50:48 +0100 | [diff] [blame] | 58 | SETUP_ENV_CHANGEENV | SETUP_ENV_TO_TMP | SETUP_ENV_CHDIR, |
| 59 | pas); |
Denis Vlasenko | 069e347 | 2008-02-16 13:17:13 +0000 | [diff] [blame] | 60 | ptr = getenv("VISUAL"); |
| 61 | if (!ptr) { |
| 62 | ptr = getenv("EDITOR"); |
| 63 | if (!ptr) |
Denis Vlasenko | b44c790 | 2008-03-17 09:29:43 +0000 | [diff] [blame] | 64 | ptr = "vi"; |
Denis Vlasenko | 069e347 | 2008-02-16 13:17:13 +0000 | [diff] [blame] | 65 | } |
| 66 | |
Denis Vlasenko | 7fc294c | 2008-02-16 13:47:57 +0000 | [diff] [blame] | 67 | BB_EXECLP(ptr, ptr, file, NULL); |
Denys Vlasenko | 681efe2 | 2011-03-08 21:00:36 +0100 | [diff] [blame] | 68 | bb_perror_msg_and_die("can't execute '%s'", ptr); |
Denis Vlasenko | 069e347 | 2008-02-16 13:17:13 +0000 | [diff] [blame] | 69 | } |
| 70 | |
Denis Vlasenko | 069e347 | 2008-02-16 13:17:13 +0000 | [diff] [blame] | 71 | int crontab_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; |
Denis Vlasenko | a60f84e | 2008-07-05 09:18:54 +0000 | [diff] [blame] | 72 | int crontab_main(int argc UNUSED_PARAM, char **argv) |
Denis Vlasenko | 069e347 | 2008-02-16 13:17:13 +0000 | [diff] [blame] | 73 | { |
| 74 | const struct passwd *pas; |
| 75 | const char *crontab_dir = CRONTABS; |
| 76 | char *tmp_fname; |
| 77 | char *new_fname; |
| 78 | char *user_name; /* -u USER */ |
| 79 | int fd; |
Denis Vlasenko | 30cfdf9 | 2008-09-21 15:29:29 +0000 | [diff] [blame] | 80 | int src_fd; |
Denis Vlasenko | 069e347 | 2008-02-16 13:17:13 +0000 | [diff] [blame] | 81 | int opt_ler; |
Denis Vlasenko | 069e347 | 2008-02-16 13:17:13 +0000 | [diff] [blame] | 82 | |
| 83 | /* file [opts] Replace crontab from file |
| 84 | * - [opts] Replace crontab from stdin |
| 85 | * -u user User |
| 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. |
| 92 | */ |
| 93 | enum { |
| 94 | OPT_u = (1 << 0), |
| 95 | OPT_c = (1 << 1), |
| 96 | OPT_l = (1 << 2), |
| 97 | OPT_e = (1 << 3), |
| 98 | OPT_r = (1 << 4), |
| 99 | OPT_ler = OPT_l + OPT_e + OPT_r, |
| 100 | }; |
| 101 | |
Denys Vlasenko | 22542ec | 2017-08-08 21:55:02 +0200 | [diff] [blame] | 102 | opt_ler = getopt32(argv, "^" "u:c:lerd" "\0" "?1:dr"/*max one arg; -d implies -r*/, |
| 103 | &user_name, &crontab_dir |
| 104 | ); |
Denis Vlasenko | 069e347 | 2008-02-16 13:17:13 +0000 | [diff] [blame] | 105 | argv += optind; |
| 106 | |
Denis Vlasenko | c9ca0a3 | 2008-02-18 11:08:33 +0000 | [diff] [blame] | 107 | if (sanitize_env_if_suid()) { /* Clears dangerous stuff, sets PATH */ |
Denys Vlasenko | b2e5fc3 | 2009-11-25 14:52:47 +0100 | [diff] [blame] | 108 | /* Run by non-root */ |
Denis Vlasenko | 7fc294c | 2008-02-16 13:47:57 +0000 | [diff] [blame] | 109 | if (opt_ler & (OPT_u|OPT_c)) |
James Byrne | 6937487 | 2019-07-02 11:35:03 +0200 | [diff] [blame] | 110 | bb_simple_error_msg_and_die(bb_msg_you_must_be_root); |
Denis Vlasenko | 7fc294c | 2008-02-16 13:47:57 +0000 | [diff] [blame] | 111 | } |
Denis Vlasenko | 069e347 | 2008-02-16 13:17:13 +0000 | [diff] [blame] | 112 | |
| 113 | if (opt_ler & OPT_u) { |
Denis Vlasenko | d7a805e | 2008-12-03 19:05:55 +0000 | [diff] [blame] | 114 | pas = xgetpwnam(user_name); |
Denis Vlasenko | 069e347 | 2008-02-16 13:17:13 +0000 | [diff] [blame] | 115 | } else { |
Denis Vlasenko | 0c68a87 | 2008-12-02 22:56:59 +0000 | [diff] [blame] | 116 | pas = xgetpwuid(getuid()); |
Denis Vlasenko | 069e347 | 2008-02-16 13:17:13 +0000 | [diff] [blame] | 117 | } |
| 118 | |
| 119 | #define user_name DONT_USE_ME_BEYOND_THIS_POINT |
Denis Vlasenko | 069e347 | 2008-02-16 13:17:13 +0000 | [diff] [blame] | 120 | |
| 121 | /* From now on, keep only -l, -e, -r bits */ |
| 122 | opt_ler &= OPT_ler; |
| 123 | if ((opt_ler - 1) & opt_ler) /* more than one bit set? */ |
| 124 | bb_show_usage(); |
| 125 | |
| 126 | /* Read replacement file under user's UID/GID/group vector */ |
Denis Vlasenko | 30cfdf9 | 2008-09-21 15:29:29 +0000 | [diff] [blame] | 127 | src_fd = STDIN_FILENO; |
Denis Vlasenko | 069e347 | 2008-02-16 13:17:13 +0000 | [diff] [blame] | 128 | if (!opt_ler) { /* Replace? */ |
| 129 | if (!argv[0]) |
| 130 | bb_show_usage(); |
| 131 | if (NOT_LONE_DASH(argv[0])) { |
Ryan Mallon | 1d30b3f | 2013-10-08 14:53:29 +0200 | [diff] [blame] | 132 | src_fd = xopen_as_uid_gid(argv[0], O_RDONLY, pas->pw_uid, pas->pw_gid); |
Denis Vlasenko | 94d5d82 | 2006-09-27 19:48:56 +0000 | [diff] [blame] | 133 | } |
| 134 | } |
Denis Vlasenko | 069e347 | 2008-02-16 13:17:13 +0000 | [diff] [blame] | 135 | |
| 136 | /* cd to our crontab directory */ |
| 137 | xchdir(crontab_dir); |
| 138 | |
| 139 | tmp_fname = NULL; |
| 140 | |
| 141 | /* Handle requested operation */ |
| 142 | switch (opt_ler) { |
| 143 | |
| 144 | default: /* case OPT_r: Delete */ |
Denis Vlasenko | 03b4c14 | 2008-02-17 14:30:03 +0000 | [diff] [blame] | 145 | unlink(pas->pw_name); |
Denis Vlasenko | 069e347 | 2008-02-16 13:17:13 +0000 | [diff] [blame] | 146 | break; |
| 147 | |
| 148 | case OPT_l: /* List */ |
| 149 | { |
| 150 | char *args[2] = { pas->pw_name, NULL }; |
| 151 | return bb_cat(args); |
| 152 | /* list exits, |
| 153 | * the rest go play with cron update file */ |
| 154 | } |
| 155 | |
| 156 | case OPT_e: /* Edit */ |
Denis Vlasenko | 7fc294c | 2008-02-16 13:47:57 +0000 | [diff] [blame] | 157 | tmp_fname = xasprintf("%s.%u", crontab_dir, (unsigned)getpid()); |
Denis Vlasenko | b44c790 | 2008-03-17 09:29:43 +0000 | [diff] [blame] | 158 | /* No O_EXCL: we don't want to be stuck if earlier crontabs |
| 159 | * were killed, leaving stale temp file behind */ |
Denis Vlasenko | 30cfdf9 | 2008-09-21 15:29:29 +0000 | [diff] [blame] | 160 | src_fd = xopen3(tmp_fname, O_RDWR|O_CREAT|O_TRUNC, 0600); |
| 161 | fchown(src_fd, pas->pw_uid, pas->pw_gid); |
Denis Vlasenko | 069e347 | 2008-02-16 13:17:13 +0000 | [diff] [blame] | 162 | fd = open(pas->pw_name, O_RDONLY); |
| 163 | if (fd >= 0) { |
Denis Vlasenko | 30cfdf9 | 2008-09-21 15:29:29 +0000 | [diff] [blame] | 164 | bb_copyfd_eof(fd, src_fd); |
Denis Vlasenko | 069e347 | 2008-02-16 13:17:13 +0000 | [diff] [blame] | 165 | close(fd); |
Denis Vlasenko | 30cfdf9 | 2008-09-21 15:29:29 +0000 | [diff] [blame] | 166 | xlseek(src_fd, 0, SEEK_SET); |
Denis Vlasenko | 069e347 | 2008-02-16 13:17:13 +0000 | [diff] [blame] | 167 | } |
Gray Wolf | 051665e | 2020-06-13 02:00:48 +0200 | [diff] [blame] | 168 | close(src_fd); |
Denis Vlasenko | 069e347 | 2008-02-16 13:17:13 +0000 | [diff] [blame] | 169 | edit_file(pas, tmp_fname); |
Gray Wolf | 051665e | 2020-06-13 02:00:48 +0200 | [diff] [blame] | 170 | /* The src_fd needs to be reopened to handle editors that do |
| 171 | * save the buffer as new file and rename it to tmp_fname (so |
| 172 | * for example vim). */ |
| 173 | src_fd = xopen3(tmp_fname, O_RDONLY, 0600); |
Denis Vlasenko | 069e347 | 2008-02-16 13:17:13 +0000 | [diff] [blame] | 174 | /* fall through */ |
| 175 | |
| 176 | case 0: /* Replace (no -l, -e, or -r were given) */ |
| 177 | new_fname = xasprintf("%s.new", pas->pw_name); |
| 178 | fd = open(new_fname, O_WRONLY|O_CREAT|O_TRUNC|O_APPEND, 0600); |
| 179 | if (fd >= 0) { |
Denis Vlasenko | 30cfdf9 | 2008-09-21 15:29:29 +0000 | [diff] [blame] | 180 | bb_copyfd_eof(src_fd, fd); |
Denis Vlasenko | 069e347 | 2008-02-16 13:17:13 +0000 | [diff] [blame] | 181 | close(fd); |
Denis Vlasenko | 03b4c14 | 2008-02-17 14:30:03 +0000 | [diff] [blame] | 182 | xrename(new_fname, pas->pw_name); |
Denis Vlasenko | 069e347 | 2008-02-16 13:17:13 +0000 | [diff] [blame] | 183 | } else { |
Denys Vlasenko | 6331cf0 | 2009-11-13 09:08:27 +0100 | [diff] [blame] | 184 | bb_error_msg("can't create %s/%s", |
Denis Vlasenko | 069e347 | 2008-02-16 13:17:13 +0000 | [diff] [blame] | 185 | crontab_dir, new_fname); |
| 186 | } |
| 187 | if (tmp_fname) |
Denis Vlasenko | 03b4c14 | 2008-02-17 14:30:03 +0000 | [diff] [blame] | 188 | unlink(tmp_fname); |
Denis Vlasenko | 069e347 | 2008-02-16 13:17:13 +0000 | [diff] [blame] | 189 | /*free(tmp_fname);*/ |
| 190 | /*free(new_fname);*/ |
Denis Vlasenko | 069e347 | 2008-02-16 13:17:13 +0000 | [diff] [blame] | 191 | } /* switch */ |
| 192 | |
| 193 | /* Bump notification file. Handle window where crond picks file up |
| 194 | * before we can write our entry out. |
| 195 | */ |
Bernhard Reutner-Fischer | 27dd495 | 2008-02-18 18:35:53 +0000 | [diff] [blame] | 196 | while ((fd = open(CRONUPDATE, O_WRONLY|O_CREAT|O_APPEND, 0600)) >= 0) { |
Denis Vlasenko | 069e347 | 2008-02-16 13:17:13 +0000 | [diff] [blame] | 197 | struct stat st; |
| 198 | |
| 199 | fdprintf(fd, "%s\n", pas->pw_name); |
| 200 | if (fstat(fd, &st) != 0 || st.st_nlink != 0) { |
| 201 | /*close(fd);*/ |
| 202 | break; |
| 203 | } |
| 204 | /* st.st_nlink == 0: |
| 205 | * file was deleted, maybe crond missed our notification */ |
| 206 | close(fd); |
| 207 | /* loop */ |
| 208 | } |
| 209 | if (fd < 0) { |
Denys Vlasenko | 6331cf0 | 2009-11-13 09:08:27 +0100 | [diff] [blame] | 210 | bb_error_msg("can't append to %s/%s", |
Denis Vlasenko | 069e347 | 2008-02-16 13:17:13 +0000 | [diff] [blame] | 211 | crontab_dir, CRONUPDATE); |
| 212 | } |
| 213 | return 0; |
Eric Andersen | f6f7bfb | 2002-10-22 12:24:59 +0000 | [diff] [blame] | 214 | } |