[821] | 1 | /* vi: set sw=4 ts=4: */
|
---|
| 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)
|
---|
| 8 | * Vladimir Oleynik <dzo@simtreas.ru> (C) 2002
|
---|
| 9 | *
|
---|
| 10 | * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
|
---|
| 11 | */
|
---|
| 12 |
|
---|
[1770] | 13 | #include "libbb.h"
|
---|
[821] | 14 |
|
---|
| 15 | #ifndef CRONTABS
|
---|
| 16 | #define CRONTABS "/var/spool/cron/crontabs"
|
---|
| 17 | #endif
|
---|
| 18 | #ifndef TMPDIR
|
---|
| 19 | #define TMPDIR "/var/spool/cron"
|
---|
| 20 | #endif
|
---|
| 21 | #ifndef CRONUPDATE
|
---|
| 22 | #define CRONUPDATE "cron.update"
|
---|
| 23 | #endif
|
---|
| 24 | #ifndef PATH_VI
|
---|
[1770] | 25 | #define PATH_VI "/bin/vi" /* location of vi */
|
---|
[821] | 26 | #endif
|
---|
| 27 |
|
---|
[1770] | 28 | static const char *CDir = CRONTABS;
|
---|
[821] | 29 |
|
---|
| 30 | static void EditFile(const char *user, const char *file);
|
---|
| 31 | static int GetReplaceStream(const char *user, const char *file);
|
---|
[1770] | 32 | static int ChangeUser(const char *user, short dochdir);
|
---|
[821] | 33 |
|
---|
[1770] | 34 | int crontab_main(int ac, char **av);
|
---|
| 35 | int crontab_main(int ac, char **av)
|
---|
[821] | 36 | {
|
---|
[1770] | 37 | enum { NONE, EDIT, LIST, REPLACE, DELETE } option = NONE;
|
---|
| 38 | const struct passwd *pas;
|
---|
| 39 | const char *repFile = NULL;
|
---|
| 40 | int repFd = 0;
|
---|
| 41 | int i;
|
---|
| 42 | char caller[256]; /* user that ran program */
|
---|
| 43 | char buf[1024];
|
---|
| 44 | int UserId;
|
---|
[821] | 45 |
|
---|
[1770] | 46 | UserId = getuid();
|
---|
| 47 | pas = getpwuid(UserId);
|
---|
| 48 | if (pas == NULL)
|
---|
| 49 | bb_perror_msg_and_die("getpwuid");
|
---|
[821] | 50 |
|
---|
[1770] | 51 | safe_strncpy(caller, pas->pw_name, sizeof(caller));
|
---|
[821] | 52 |
|
---|
[1770] | 53 | i = 1;
|
---|
| 54 | if (ac > 1) {
|
---|
| 55 | if (LONE_DASH(av[1])) {
|
---|
| 56 | option = REPLACE;
|
---|
| 57 | ++i;
|
---|
| 58 | } else if (av[1][0] != '-') {
|
---|
| 59 | option = REPLACE;
|
---|
| 60 | ++i;
|
---|
| 61 | repFile = av[1];
|
---|
| 62 | }
|
---|
[821] | 63 | }
|
---|
| 64 |
|
---|
[1770] | 65 | for (; i < ac; ++i) {
|
---|
| 66 | char *ptr = av[i];
|
---|
[821] | 67 |
|
---|
[1770] | 68 | if (*ptr != '-')
|
---|
| 69 | break;
|
---|
| 70 | ptr += 2;
|
---|
[821] | 71 |
|
---|
[1770] | 72 | switch (ptr[-1]) {
|
---|
| 73 | case 'l':
|
---|
| 74 | if (ptr[-1] == 'l')
|
---|
| 75 | option = LIST;
|
---|
| 76 | /* fall through */
|
---|
| 77 | case 'e':
|
---|
| 78 | if (ptr[-1] == 'e')
|
---|
| 79 | option = EDIT;
|
---|
| 80 | /* fall through */
|
---|
| 81 | case 'd':
|
---|
| 82 | if (ptr[-1] == 'd')
|
---|
| 83 | option = DELETE;
|
---|
| 84 | /* fall through */
|
---|
| 85 | case 'u':
|
---|
| 86 | if (i + 1 < ac && av[i+1][0] != '-') {
|
---|
| 87 | ++i;
|
---|
| 88 | if (getuid() == geteuid()) {
|
---|
| 89 | pas = getpwnam(av[i]);
|
---|
| 90 | if (pas) {
|
---|
| 91 | UserId = pas->pw_uid;
|
---|
| 92 | } else {
|
---|
| 93 | bb_error_msg_and_die("user %s unknown", av[i]);
|
---|
| 94 | }
|
---|
| 95 | } else {
|
---|
| 96 | bb_error_msg_and_die("only the superuser may specify a user");
|
---|
| 97 | }
|
---|
| 98 | }
|
---|
| 99 | break;
|
---|
| 100 | case 'c':
|
---|
| 101 | if (getuid() == geteuid()) {
|
---|
| 102 | CDir = (*ptr) ? ptr : av[++i];
|
---|
| 103 | } else {
|
---|
| 104 | bb_error_msg_and_die("-c option: superuser only");
|
---|
| 105 | }
|
---|
| 106 | break;
|
---|
| 107 | default:
|
---|
| 108 | i = ac;
|
---|
| 109 | break;
|
---|
[821] | 110 | }
|
---|
| 111 | }
|
---|
[1770] | 112 | if (i != ac || option == NONE)
|
---|
| 113 | bb_show_usage();
|
---|
[821] | 114 |
|
---|
[1770] | 115 | /*
|
---|
| 116 | * Get password entry
|
---|
| 117 | */
|
---|
[821] | 118 |
|
---|
[1770] | 119 | pas = getpwuid(UserId);
|
---|
| 120 | if (pas == NULL)
|
---|
| 121 | bb_perror_msg_and_die("getpwuid");
|
---|
[821] | 122 |
|
---|
[1770] | 123 | /*
|
---|
| 124 | * If there is a replacement file, obtain a secure descriptor to it.
|
---|
| 125 | */
|
---|
[821] | 126 |
|
---|
[1770] | 127 | if (repFile) {
|
---|
| 128 | repFd = GetReplaceStream(caller, repFile);
|
---|
| 129 | if (repFd < 0)
|
---|
| 130 | bb_error_msg_and_die("cannot read replacement file");
|
---|
| 131 | }
|
---|
[821] | 132 |
|
---|
[1770] | 133 | /*
|
---|
| 134 | * Change directory to our crontab directory
|
---|
| 135 | */
|
---|
[821] | 136 |
|
---|
[1770] | 137 | xchdir(CDir);
|
---|
[821] | 138 |
|
---|
[1770] | 139 | /*
|
---|
| 140 | * Handle options as appropriate
|
---|
| 141 | */
|
---|
[821] | 142 |
|
---|
[1770] | 143 | switch (option) {
|
---|
| 144 | case LIST:
|
---|
| 145 | {
|
---|
| 146 | FILE *fi;
|
---|
[821] | 147 |
|
---|
[1770] | 148 | fi = fopen(pas->pw_name, "r");
|
---|
| 149 | if (fi) {
|
---|
| 150 | while (fgets(buf, sizeof(buf), fi) != NULL)
|
---|
| 151 | fputs(buf, stdout);
|
---|
| 152 | fclose(fi);
|
---|
| 153 | } else {
|
---|
| 154 | bb_error_msg("no crontab for %s", pas->pw_name);
|
---|
| 155 | }
|
---|
| 156 | }
|
---|
| 157 | break;
|
---|
| 158 | case EDIT:
|
---|
| 159 | {
|
---|
| 160 | /* FIXME: messy code here! we have file copying helpers for this! */
|
---|
| 161 | FILE *fi;
|
---|
| 162 | int fd;
|
---|
| 163 | int n;
|
---|
| 164 | char tmp[128];
|
---|
[821] | 165 |
|
---|
[1770] | 166 | snprintf(tmp, sizeof(tmp), TMPDIR "/crontab.%d", getpid());
|
---|
| 167 | fd = xopen3(tmp, O_RDWR|O_CREAT|O_TRUNC|O_EXCL, 0600);
|
---|
| 168 | /* race, use fchown */
|
---|
| 169 | chown(tmp, getuid(), getgid());
|
---|
| 170 | fi = fopen(pas->pw_name, "r");
|
---|
| 171 | if (fi) {
|
---|
| 172 | while ((n = fread(buf, 1, sizeof(buf), fi)) > 0)
|
---|
| 173 | full_write(fd, buf, n);
|
---|
| 174 | }
|
---|
| 175 | EditFile(caller, tmp);
|
---|
| 176 | remove(tmp);
|
---|
| 177 | lseek(fd, 0L, SEEK_SET);
|
---|
| 178 | repFd = fd;
|
---|
| 179 | }
|
---|
| 180 | option = REPLACE;
|
---|
| 181 | /* fall through */
|
---|
| 182 | case REPLACE:
|
---|
| 183 | {
|
---|
| 184 | /* same here */
|
---|
| 185 | char path[1024];
|
---|
| 186 | int fd;
|
---|
| 187 | int n;
|
---|
[821] | 188 |
|
---|
[1770] | 189 | snprintf(path, sizeof(path), "%s.new", pas->pw_name);
|
---|
| 190 | fd = open(path, O_CREAT|O_TRUNC|O_APPEND|O_WRONLY, 0600);
|
---|
| 191 | if (fd >= 0) {
|
---|
| 192 | while ((n = read(repFd, buf, sizeof(buf))) > 0) {
|
---|
| 193 | full_write(fd, buf, n);
|
---|
| 194 | }
|
---|
| 195 | close(fd);
|
---|
| 196 | rename(path, pas->pw_name);
|
---|
| 197 | } else {
|
---|
| 198 | bb_error_msg("cannot create %s/%s", CDir, path);
|
---|
| 199 | }
|
---|
| 200 | close(repFd);
|
---|
[821] | 201 | }
|
---|
[1770] | 202 | break;
|
---|
| 203 | case DELETE:
|
---|
| 204 | remove(pas->pw_name);
|
---|
| 205 | break;
|
---|
| 206 | case NONE:
|
---|
| 207 | default:
|
---|
| 208 | break;
|
---|
[821] | 209 | }
|
---|
| 210 |
|
---|
[1770] | 211 | /*
|
---|
| 212 | * Bump notification file. Handle window where crond picks file up
|
---|
| 213 | * before we can write our entry out.
|
---|
| 214 | */
|
---|
[821] | 215 |
|
---|
[1770] | 216 | if (option == REPLACE || option == DELETE) {
|
---|
| 217 | FILE *fo;
|
---|
| 218 | struct stat st;
|
---|
[821] | 219 |
|
---|
[1770] | 220 | while ((fo = fopen(CRONUPDATE, "a"))) {
|
---|
| 221 | fprintf(fo, "%s\n", pas->pw_name);
|
---|
| 222 | fflush(fo);
|
---|
| 223 | if (fstat(fileno(fo), &st) != 0 || st.st_nlink != 0) {
|
---|
| 224 | fclose(fo);
|
---|
| 225 | break;
|
---|
| 226 | }
|
---|
| 227 | fclose(fo);
|
---|
| 228 | /* loop */
|
---|
| 229 | }
|
---|
| 230 | if (fo == NULL) {
|
---|
| 231 | bb_error_msg("cannot append to %s/%s", CDir, CRONUPDATE);
|
---|
| 232 | }
|
---|
[821] | 233 | }
|
---|
[1770] | 234 | return 0;
|
---|
[821] | 235 | }
|
---|
| 236 |
|
---|
[1770] | 237 | static int GetReplaceStream(const char *user, const char *file)
|
---|
[821] | 238 | {
|
---|
[1770] | 239 | int filedes[2];
|
---|
| 240 | int pid;
|
---|
| 241 | int fd;
|
---|
| 242 | int n;
|
---|
| 243 | char buf[1024];
|
---|
[821] | 244 |
|
---|
[1770] | 245 | if (pipe(filedes) < 0) {
|
---|
| 246 | perror("pipe");
|
---|
| 247 | return -1;
|
---|
| 248 | }
|
---|
| 249 | pid = fork();
|
---|
| 250 | if (pid < 0) {
|
---|
| 251 | perror("fork");
|
---|
| 252 | return -1;
|
---|
| 253 | }
|
---|
| 254 | if (pid > 0) {
|
---|
| 255 | /*
|
---|
| 256 | * PARENT
|
---|
| 257 | */
|
---|
| 258 |
|
---|
| 259 | close(filedes[1]);
|
---|
| 260 | if (read(filedes[0], buf, 1) != 1) {
|
---|
| 261 | close(filedes[0]);
|
---|
| 262 | filedes[0] = -1;
|
---|
| 263 | }
|
---|
| 264 | return filedes[0];
|
---|
| 265 | }
|
---|
| 266 |
|
---|
[821] | 267 | /*
|
---|
[1770] | 268 | * CHILD
|
---|
[821] | 269 | */
|
---|
| 270 |
|
---|
[1770] | 271 | close(filedes[0]);
|
---|
| 272 |
|
---|
| 273 | if (ChangeUser(user, 0) < 0)
|
---|
| 274 | exit(0);
|
---|
| 275 |
|
---|
| 276 | xfunc_error_retval = 0;
|
---|
| 277 | fd = xopen(file, O_RDONLY);
|
---|
| 278 | buf[0] = 0;
|
---|
| 279 | write(filedes[1], buf, 1);
|
---|
| 280 | while ((n = read(fd, buf, sizeof(buf))) > 0) {
|
---|
| 281 | write(filedes[1], buf, n);
|
---|
[821] | 282 | }
|
---|
[1770] | 283 | exit(0);
|
---|
| 284 | }
|
---|
[821] | 285 |
|
---|
[1770] | 286 | static void EditFile(const char *user, const char *file)
|
---|
| 287 | {
|
---|
| 288 | int pid = fork();
|
---|
[821] | 289 |
|
---|
[1770] | 290 | if (pid == 0) {
|
---|
| 291 | /*
|
---|
| 292 | * CHILD - change user and run editor
|
---|
| 293 | */
|
---|
| 294 | const char *ptr;
|
---|
[821] | 295 |
|
---|
[1770] | 296 | if (ChangeUser(user, 1) < 0)
|
---|
| 297 | exit(0);
|
---|
| 298 | ptr = getenv("VISUAL");
|
---|
| 299 | if (ptr == NULL)
|
---|
| 300 | ptr = getenv("EDITOR");
|
---|
| 301 | if (ptr == NULL)
|
---|
| 302 | ptr = PATH_VI;
|
---|
[821] | 303 |
|
---|
[1770] | 304 | ptr = xasprintf("%s %s", ptr, file);
|
---|
| 305 | execl(DEFAULT_SHELL, DEFAULT_SHELL, "-c", ptr, NULL);
|
---|
| 306 | bb_perror_msg_and_die("exec");
|
---|
| 307 | }
|
---|
| 308 | if (pid < 0) {
|
---|
| 309 | /*
|
---|
| 310 | * PARENT - failure
|
---|
| 311 | */
|
---|
| 312 | bb_perror_msg_and_die("fork");
|
---|
| 313 | }
|
---|
| 314 | wait4(pid, NULL, 0, NULL);
|
---|
[821] | 315 | }
|
---|
| 316 |
|
---|
[1770] | 317 | static int ChangeUser(const char *user, short dochdir)
|
---|
[821] | 318 | {
|
---|
[1770] | 319 | struct passwd *pas;
|
---|
[821] | 320 |
|
---|
| 321 | /*
|
---|
[1770] | 322 | * Obtain password entry and change privileges
|
---|
[821] | 323 | */
|
---|
| 324 |
|
---|
[1770] | 325 | pas = getpwnam(user);
|
---|
| 326 | if (pas == NULL) {
|
---|
| 327 | bb_perror_msg_and_die("failed to get uid for %s", user);
|
---|
| 328 | }
|
---|
| 329 | setenv("USER", pas->pw_name, 1);
|
---|
| 330 | setenv("HOME", pas->pw_dir, 1);
|
---|
| 331 | setenv("SHELL", DEFAULT_SHELL, 1);
|
---|
[821] | 332 |
|
---|
| 333 | /*
|
---|
[1770] | 334 | * Change running state to the user in question
|
---|
[821] | 335 | */
|
---|
[1770] | 336 | change_identity(pas);
|
---|
[821] | 337 |
|
---|
[1770] | 338 | if (dochdir) {
|
---|
| 339 | if (chdir(pas->pw_dir) < 0) {
|
---|
| 340 | bb_perror_msg("chdir(%s) by %s failed", pas->pw_dir, user);
|
---|
| 341 | xchdir(TMPDIR);
|
---|
| 342 | }
|
---|
[821] | 343 | }
|
---|
[1770] | 344 | return pas->pw_uid;
|
---|
[821] | 345 | }
|
---|