Contents of /trunk/mkinitrd-magellan/busybox/miscutils/crontab.c
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Sat Sep 1 22:45:15 2007 UTC (17 years ago) by niro
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Sat Sep 1 22:45:15 2007 UTC (17 years ago) by niro
File MIME type: text/plain
File size: 6556 byte(s)
-import if magellan mkinitrd; it is a fork of redhats mkinitrd-5.0.8 with all magellan patches and features; deprecates magellan-src/mkinitrd
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 | |
13 | #include "busybox.h" |
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 |
25 | #define PATH_VI "/bin/vi" /* location of vi */ |
26 | #endif |
27 | |
28 | static const char *CDir = CRONTABS; |
29 | |
30 | static void EditFile(const char *user, const char *file); |
31 | static int GetReplaceStream(const char *user, const char *file); |
32 | static int ChangeUser(const char *user, short dochdir); |
33 | |
34 | int crontab_main(int ac, char **av) |
35 | { |
36 | enum { NONE, EDIT, LIST, REPLACE, DELETE } option = NONE; |
37 | const struct passwd *pas; |
38 | const char *repFile = NULL; |
39 | int repFd = 0; |
40 | int i; |
41 | char caller[256]; /* user that ran program */ |
42 | char buf[1024]; |
43 | int UserId; |
44 | |
45 | UserId = getuid(); |
46 | pas = getpwuid(UserId); |
47 | if (pas == NULL) |
48 | bb_perror_msg_and_die("getpwuid"); |
49 | |
50 | safe_strncpy(caller, pas->pw_name, sizeof(caller)); |
51 | |
52 | i = 1; |
53 | if (ac > 1) { |
54 | if (LONE_DASH(av[1])) { |
55 | option = REPLACE; |
56 | ++i; |
57 | } else if (av[1][0] != '-') { |
58 | option = REPLACE; |
59 | ++i; |
60 | repFile = av[1]; |
61 | } |
62 | } |
63 | |
64 | for (; i < ac; ++i) { |
65 | char *ptr = av[i]; |
66 | |
67 | if (*ptr != '-') |
68 | break; |
69 | ptr += 2; |
70 | |
71 | switch (ptr[-1]) { |
72 | case 'l': |
73 | if (ptr[-1] == 'l') |
74 | option = LIST; |
75 | /* fall through */ |
76 | case 'e': |
77 | if (ptr[-1] == 'e') |
78 | option = EDIT; |
79 | /* fall through */ |
80 | case 'd': |
81 | if (ptr[-1] == 'd') |
82 | option = DELETE; |
83 | /* fall through */ |
84 | case 'u': |
85 | if (i + 1 < ac && av[i+1][0] != '-') { |
86 | ++i; |
87 | if (getuid() == geteuid()) { |
88 | pas = getpwnam(av[i]); |
89 | if (pas) { |
90 | UserId = pas->pw_uid; |
91 | } else { |
92 | bb_error_msg_and_die("user %s unknown", av[i]); |
93 | } |
94 | } else { |
95 | bb_error_msg_and_die("only the superuser may specify a user"); |
96 | } |
97 | } |
98 | break; |
99 | case 'c': |
100 | if (getuid() == geteuid()) { |
101 | CDir = (*ptr) ? ptr : av[++i]; |
102 | } else { |
103 | bb_error_msg_and_die("-c option: superuser only"); |
104 | } |
105 | break; |
106 | default: |
107 | i = ac; |
108 | break; |
109 | } |
110 | } |
111 | if (i != ac || option == NONE) |
112 | bb_show_usage(); |
113 | |
114 | /* |
115 | * Get password entry |
116 | */ |
117 | |
118 | pas = getpwuid(UserId); |
119 | if (pas == NULL) |
120 | bb_perror_msg_and_die("getpwuid"); |
121 | |
122 | /* |
123 | * If there is a replacement file, obtain a secure descriptor to it. |
124 | */ |
125 | |
126 | if (repFile) { |
127 | repFd = GetReplaceStream(caller, repFile); |
128 | if (repFd < 0) |
129 | bb_error_msg_and_die("cannot read replacement file"); |
130 | } |
131 | |
132 | /* |
133 | * Change directory to our crontab directory |
134 | */ |
135 | |
136 | xchdir(CDir); |
137 | |
138 | /* |
139 | * Handle options as appropriate |
140 | */ |
141 | |
142 | switch (option) { |
143 | case LIST: |
144 | { |
145 | FILE *fi; |
146 | |
147 | fi = fopen(pas->pw_name, "r"); |
148 | if (fi) { |
149 | while (fgets(buf, sizeof(buf), fi) != NULL) |
150 | fputs(buf, stdout); |
151 | fclose(fi); |
152 | } else { |
153 | bb_error_msg("no crontab for %s", pas->pw_name); |
154 | } |
155 | } |
156 | break; |
157 | case EDIT: |
158 | { |
159 | /* FIXME: messy code here! we have file copying helpers for this! */ |
160 | FILE *fi; |
161 | int fd; |
162 | int n; |
163 | char tmp[128]; |
164 | |
165 | snprintf(tmp, sizeof(tmp), TMPDIR "/crontab.%d", getpid()); |
166 | fd = xopen3(tmp, O_RDWR|O_CREAT|O_TRUNC|O_EXCL, 0600); |
167 | /* race, use fchown */ |
168 | chown(tmp, getuid(), getgid()); |
169 | fi = fopen(pas->pw_name, "r"); |
170 | if (fi) { |
171 | while ((n = fread(buf, 1, sizeof(buf), fi)) > 0) |
172 | full_write(fd, buf, n); |
173 | } |
174 | EditFile(caller, tmp); |
175 | remove(tmp); |
176 | lseek(fd, 0L, SEEK_SET); |
177 | repFd = fd; |
178 | } |
179 | option = REPLACE; |
180 | /* fall through */ |
181 | case REPLACE: |
182 | { |
183 | /* same here */ |
184 | char path[1024]; |
185 | int fd; |
186 | int n; |
187 | |
188 | snprintf(path, sizeof(path), "%s.new", pas->pw_name); |
189 | fd = open(path, O_CREAT|O_TRUNC|O_APPEND|O_WRONLY, 0600); |
190 | if (fd >= 0) { |
191 | while ((n = read(repFd, buf, sizeof(buf))) > 0) { |
192 | full_write(fd, buf, n); |
193 | } |
194 | close(fd); |
195 | rename(path, pas->pw_name); |
196 | } else { |
197 | bb_error_msg("cannot create %s/%s", CDir, path); |
198 | } |
199 | close(repFd); |
200 | } |
201 | break; |
202 | case DELETE: |
203 | remove(pas->pw_name); |
204 | break; |
205 | case NONE: |
206 | default: |
207 | break; |
208 | } |
209 | |
210 | /* |
211 | * Bump notification file. Handle window where crond picks file up |
212 | * before we can write our entry out. |
213 | */ |
214 | |
215 | if (option == REPLACE || option == DELETE) { |
216 | FILE *fo; |
217 | struct stat st; |
218 | |
219 | while ((fo = fopen(CRONUPDATE, "a"))) { |
220 | fprintf(fo, "%s\n", pas->pw_name); |
221 | fflush(fo); |
222 | if (fstat(fileno(fo), &st) != 0 || st.st_nlink != 0) { |
223 | fclose(fo); |
224 | break; |
225 | } |
226 | fclose(fo); |
227 | /* loop */ |
228 | } |
229 | if (fo == NULL) { |
230 | bb_error_msg("cannot append to %s/%s", CDir, CRONUPDATE); |
231 | } |
232 | } |
233 | return 0; |
234 | } |
235 | |
236 | static int GetReplaceStream(const char *user, const char *file) |
237 | { |
238 | int filedes[2]; |
239 | int pid; |
240 | int fd; |
241 | int n; |
242 | char buf[1024]; |
243 | |
244 | if (pipe(filedes) < 0) { |
245 | perror("pipe"); |
246 | return -1; |
247 | } |
248 | pid = fork(); |
249 | if (pid < 0) { |
250 | perror("fork"); |
251 | return -1; |
252 | } |
253 | if (pid > 0) { |
254 | /* |
255 | * PARENT |
256 | */ |
257 | |
258 | close(filedes[1]); |
259 | if (read(filedes[0], buf, 1) != 1) { |
260 | close(filedes[0]); |
261 | filedes[0] = -1; |
262 | } |
263 | return filedes[0]; |
264 | } |
265 | |
266 | /* |
267 | * CHILD |
268 | */ |
269 | |
270 | close(filedes[0]); |
271 | |
272 | if (ChangeUser(user, 0) < 0) |
273 | exit(0); |
274 | |
275 | xfunc_error_retval = 0; |
276 | fd = xopen(file, O_RDONLY); |
277 | buf[0] = 0; |
278 | write(filedes[1], buf, 1); |
279 | while ((n = read(fd, buf, sizeof(buf))) > 0) { |
280 | write(filedes[1], buf, n); |
281 | } |
282 | exit(0); |
283 | } |
284 | |
285 | static void EditFile(const char *user, const char *file) |
286 | { |
287 | int pid = fork(); |
288 | |
289 | if (pid == 0) { |
290 | /* |
291 | * CHILD - change user and run editor |
292 | */ |
293 | char *ptr; |
294 | char visual[1024]; |
295 | |
296 | if (ChangeUser(user, 1) < 0) |
297 | exit(0); |
298 | ptr = getenv("VISUAL"); |
299 | if (ptr == NULL || strlen(ptr) > 256) |
300 | ptr = PATH_VI; |
301 | |
302 | snprintf(visual, sizeof(visual), "%s %s", ptr, file); |
303 | execl(DEFAULT_SHELL, DEFAULT_SHELL, "-c", visual, NULL); |
304 | perror("exec"); |
305 | exit(0); |
306 | } |
307 | if (pid < 0) { |
308 | /* |
309 | * PARENT - failure |
310 | */ |
311 | bb_perror_msg_and_die("fork"); |
312 | } |
313 | wait4(pid, NULL, 0, NULL); |
314 | } |
315 | |
316 | static int ChangeUser(const char *user, short dochdir) |
317 | { |
318 | struct passwd *pas; |
319 | |
320 | /* |
321 | * Obtain password entry and change privileges |
322 | */ |
323 | |
324 | pas = getpwnam(user); |
325 | if (pas == NULL) { |
326 | bb_perror_msg_and_die("failed to get uid for %s", user); |
327 | } |
328 | setenv("USER", pas->pw_name, 1); |
329 | setenv("HOME", pas->pw_dir, 1); |
330 | setenv("SHELL", DEFAULT_SHELL, 1); |
331 | |
332 | /* |
333 | * Change running state to the user in question |
334 | */ |
335 | change_identity(pas); |
336 | |
337 | if (dochdir) { |
338 | if (chdir(pas->pw_dir) < 0) { |
339 | bb_perror_msg("chdir(%s) by %s failed", pas->pw_dir, user); |
340 | xchdir(TMPDIR); |
341 | } |
342 | } |
343 | return pas->pw_uid; |
344 | } |