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1 | /* | |
2 | * | |
3 | * Copyright (c) 2001 Michal Moskal <malekith@pld-linux.org>. | |
4 | * All rights reserved. | |
5 | * | |
6 | * Redistribution and use in source and binary forms, with or without | |
7 | * modification, are permitted provided that the following conditions | |
8 | * are met: | |
9 | * 1. Redistributions of source code must retain the above copyright | |
10 | * notice, this list of conditions and the following disclaimer. | |
11 | * 2. Redistributions in binary form must reproduce the above copyright | |
12 | * notice, this list of conditions and the following disclaimer in the | |
13 | * documentation and/or other materials provided with the distribution. | |
14 | * 3. All advertising materials mentioning features or use of this software | |
15 | * must display the following acknowledgement: | |
16 | * This product includes software developed by Michal Moskal. | |
17 | * 4. Neither the name of the author nor the names of any co-contributors | |
18 | * may be used to endorse or promote products derived from this software | |
19 | * without specific prior written permission. | |
20 | * | |
21 | * THIS SOFTWARE IS PROVIDED BY MICHAL MOSKAL AND CONTRIBUTORS ``AS IS'' AND | |
22 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |
23 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | |
24 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE | |
25 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL | |
26 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS | |
27 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) | |
28 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT | |
29 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY | |
30 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF | |
31 | * SUCH DAMAGE. | |
32 | * | |
33 | * | |
34 | * | |
35 | * USAGE: joinpasswd | |
36 | * | |
37 | * Add entries from freshly created {passwd,shadow,group}.rpmnew to existing | |
38 | * {passwd,shadow,group}. It is usable as part of setup package, during upgrade | |
39 | * where new system user/group is to be added. If entry is already found in | |
40 | * system database, it is left, otherwise it is added. UIDs/GIDs are *not* | |
41 | * checked anyhow. | |
42 | * | |
43 | * For typical sizes of files in setup package, it takes about 1 second per | |
44 | * 20000 users in system database on Pentium class machine. After static link | |
45 | * against uClibc it is under 2k on x86. Stdio hasn't been used intentionally. | |
46 | * | |
47 | * Written for PLD Linux (http://www.pld-linux.org/) setup package. | |
48 | * | |
49 | * Compilation against uClibc: | |
50 | * UCROOT=/usr/lib/bootdisk/usr | |
51 | * gcc -I$UCROOT/include -nostdlib -O2 joinpasswd.c $UCROOT/lib/crt0.o \ | |
52 | * $UCROOT/lib/libc.a -lgcc -o joinpasswd | |
53 | * strip -R .comment -R .note joinpasswd | |
54 | * | |
55 | * The idea of this program comes from Lukasz Dobrek <dobrek@pld-linux.org>. | |
56 | * | |
57 | */ | |
58 | ||
59 | #include <sys/types.h> | |
60 | #include <sys/mman.h> | |
61 | #include <sys/stat.h> | |
62 | #include <stdio.h> | |
63 | #include <errno.h> | |
64 | #include <unistd.h> | |
65 | #include <stdarg.h> | |
66 | #include <fcntl.h> | |
67 | #include <stdlib.h> | |
68 | #include <string.h> | |
69 | #include <signal.h> | |
70 | ||
71 | #define FILE1 "/etc/passwd" | |
72 | #define FILE2 "/etc/shadow" | |
73 | #define FILE3 "/etc/group" | |
74 | #define FILE4 "/etc/gshadow" | |
75 | ||
76 | /* #define OLD_LOCK */ | |
77 | ||
78 | #define LOCK_FILE "/etc/.pwd.lock" | |
79 | ||
80 | #define SUFFIX ".rpmnew" | |
81 | /* maybe "-" or sth? */ | |
82 | #define BACKUP ".old" | |
83 | ||
84 | /* #define SILENT */ | |
85 | ||
86 | void eputs(const char *fmt, ...) | |
87 | { | |
88 | va_list args; | |
89 | ||
90 | va_start(args, fmt); | |
91 | vfprintf(stderr, fmt, args); | |
92 | va_end(args); | |
93 | } | |
94 | ||
95 | void fatal(const char *fmt, ...) | |
96 | { | |
97 | va_list args; | |
98 | ||
99 | va_start(args, fmt); | |
100 | eputs(fmt, args); | |
101 | va_end(args); | |
102 | ||
103 | eputs("\n"); | |
104 | exit(1); | |
105 | } | |
106 | ||
107 | char *map_file(const char *name, ssize_t *sz) | |
108 | { | |
109 | int fd; | |
110 | void *ptr; | |
111 | struct stat st; | |
112 | ||
113 | fd = open(name, O_RDONLY); | |
114 | if (fd == -1) | |
115 | return NULL; | |
116 | if (fstat(fd, &st) < 0) | |
117 | return NULL; | |
118 | *sz = st.st_size; | |
119 | ptr = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0); | |
120 | if (ptr == MAP_FAILED) | |
121 | return NULL; | |
122 | ||
123 | return ptr; | |
124 | } | |
125 | ||
126 | int exist(char *id, int id_len, char *ptr, ssize_t sz) | |
127 | { | |
128 | ssize_t i; | |
129 | ||
130 | for (i = 0; i < sz; ) { | |
131 | if (sz - i > id_len && memcmp(id, ptr + i, id_len + 1) == 0) | |
132 | return 1; | |
133 | while (i < sz && ptr[i] != '\n') | |
134 | i++; | |
135 | i++; | |
136 | } | |
137 | ||
138 | return 0; | |
139 | } | |
140 | ||
141 | void itoa(char *buf, long i) | |
142 | { | |
143 | char tmp[32]; | |
144 | char *p; | |
145 | ||
146 | if (i < 0) { | |
147 | strcpy(buf, "-"); | |
148 | buf++; | |
149 | i = -i; | |
150 | } | |
151 | if (i == 0) { | |
152 | strcpy(buf, "0"); | |
153 | return; | |
154 | } | |
155 | for (p = tmp; i; i /= 10) | |
156 | *p++ = (i % 10) + '0'; | |
157 | while (p > tmp) | |
158 | *buf++ = *--p; | |
159 | *buf = 0; | |
160 | } | |
161 | ||
162 | #ifndef OLD_LOCK | |
163 | int lock_fd = -1; | |
164 | void noop(int x) | |
165 | { | |
166 | (void)x; | |
167 | } | |
168 | #endif | |
169 | ||
170 | int try_lock(const char *name) | |
171 | { | |
172 | #ifdef OLD_LOCK | |
173 | char file[strlen(name) + 32], lock[strlen(name) + 32]; | |
174 | char buf[32]; | |
175 | int fd; | |
176 | long pid; | |
177 | ||
178 | strcpy(lock, name); | |
179 | strcpy(file, name); | |
180 | strcat(lock, ".lock"); | |
181 | itoa(buf, (long)getpid()); | |
182 | strcat(file, "."); | |
183 | strcat(file, buf); | |
184 | ||
185 | fd = open(file, O_WRONLY|O_CREAT|O_EXCL|O_TRUNC, 0600); | |
186 | if (fd < 0) | |
187 | return -1; | |
188 | if (write(fd, buf, strlen(buf)) < 0) { | |
189 | close(fd); | |
190 | return -1; | |
191 | } | |
192 | if (close(fd) < 0) | |
193 | return -1; | |
194 | ||
195 | if (link(file, lock) == 0) { | |
196 | unlink(file); | |
197 | return 0; | |
198 | } | |
199 | ||
200 | fd = open(lock, O_RDONLY); | |
201 | if (fd < 0) | |
202 | goto oops; | |
203 | memset(buf, 0, sizeof(buf)); | |
204 | read(fd, buf, sizeof(buf)); | |
205 | pid = atol(buf); | |
206 | if (pid == 0 || kill(pid, 0) != 0) { | |
207 | /* stale lock */ | |
208 | unlink(file); | |
209 | unlink(lock); | |
210 | /* try again */ | |
211 | return try_lock(name); | |
212 | } | |
213 | ||
214 | oops: | |
215 | unlink(file); | |
216 | return -1; | |
217 | #else | |
218 | struct flock fl; | |
219 | ||
220 | if (lock_fd != -1) | |
221 | return -1; | |
222 | lock_fd = open(LOCK_FILE, O_RDWR|O_CREAT, 0600); | |
223 | if (lock_fd == -1) | |
224 | return -1; | |
225 | signal(SIGALRM, noop); | |
226 | alarm(15); | |
227 | memset(&fl, 0, sizeof(fl)); | |
228 | fl.l_type = F_WRLCK; | |
229 | fl.l_whence = SEEK_SET; | |
230 | if (fcntl(lock_fd, F_SETLKW, &fl) != 0) { | |
231 | alarm(0); | |
232 | close(lock_fd); | |
233 | lock_fd = -1; | |
234 | return -1; | |
235 | } | |
236 | alarm(0); | |
237 | ||
238 | return 0; | |
239 | #endif | |
240 | } | |
241 | ||
242 | void unlock(const char *name) | |
243 | { | |
244 | #ifdef OLD_LOCK | |
245 | char lock[strlen(name) + 32]; | |
246 | ||
247 | strcpy(lock, name); | |
248 | strcat(lock, ".lock"); | |
249 | unlink(lock); | |
250 | #else | |
251 | if (lock_fd != -1) | |
252 | close(lock_fd); | |
253 | lock_fd = -1; | |
254 | #endif | |
255 | } | |
256 | ||
257 | void lock(const char *name) | |
258 | { | |
259 | int n; | |
260 | ||
261 | n = 5; | |
262 | while (n--) { | |
263 | if (try_lock(name) == 0) | |
264 | return; | |
265 | eputs("waiting for lock...\n"); | |
266 | sleep(1); | |
267 | } | |
268 | fatal("cannot get lock"); | |
269 | } | |
270 | ||
271 | int join(const char *old_name, const char *new_name, const char *backup_name) | |
272 | { | |
273 | char *old, *new, *id; | |
274 | int i, fd; | |
275 | ssize_t old_sz, new_sz; | |
276 | ||
277 | new = map_file(new_name, &new_sz); | |
278 | if (new == NULL) | |
279 | return -1; | |
280 | ||
281 | lock(old_name); | |
282 | old = map_file(old_name, &old_sz); | |
283 | if (old == NULL) | |
284 | fatal("cannot mmap file `%s': %m", old_name); | |
285 | ||
286 | fd = open(backup_name, O_WRONLY|O_CREAT|O_TRUNC, 0600); | |
287 | if (fd < 0) | |
288 | fatal("cannot create backup file `%s': %m", backup_name); | |
289 | if (write(fd, old, old_sz) < 0) | |
290 | fatal("writting to backup file `%s' failed: %m", backup_name); | |
291 | if (fsync(fd) < 0) | |
292 | fatal("syncing backup file `%s' failed: %m", backup_name); | |
293 | if (close(fd) < 0) | |
294 | fatal("closing backup file `%s' failed: %m", backup_name); | |
295 | ||
296 | #ifndef SILENT | |
297 | eputs("merging content of `"); | |
298 | eputs(old_name); | |
299 | eputs("' with `"); | |
300 | eputs(new_name); | |
301 | eputs("'\n"); | |
302 | #endif /* SILENT */ | |
303 | ||
304 | fd = open(old_name, O_WRONLY|O_APPEND); | |
305 | if (fd < 0) | |
306 | fatal("cannot open old file `%s': %m", old_name); | |
307 | ||
308 | for (i = 0; i < new_sz; ) { | |
309 | id = new + i; | |
310 | while (i < new_sz && new[i] != ':' && new[i] != '\n') | |
311 | i++; | |
312 | if (i < new_sz && new[i] == ':') { | |
313 | int id_len, line_len; | |
314 | ||
315 | id_len = i - (id - new); | |
316 | while (i < new_sz && new[i] != '\n') | |
317 | i++; | |
318 | if (i < new_sz) | |
319 | i++; | |
320 | line_len = i - (id - new); | |
321 | ||
322 | if (!exist(id, id_len, old, old_sz)) { | |
323 | #ifndef SILENT | |
324 | eputs(old_name); | |
325 | eputs(": adding `"); | |
326 | write(2, id, id_len); | |
327 | eputs("'\n"); | |
328 | #endif /* SILENT */ | |
329 | if (write(fd, id, line_len) < 0) | |
330 | fatal("writting line to `%s' failed, check backup file: %m", old_name); | |
331 | } | |
332 | } else if (i < new_sz) | |
333 | i++; | |
334 | } | |
335 | fsync(fd); | |
336 | close(fd); | |
337 | ||
338 | #if 0 | |
339 | /* user may want to exime this file... */ | |
340 | unlink(new_name); | |
341 | #endif | |
342 | unlock(old_name); | |
343 | ||
344 | return 0; | |
345 | } | |
346 | ||
347 | int main() | |
348 | { | |
349 | #if 1 | |
350 | join(FILE1, FILE1 SUFFIX, FILE1 BACKUP); | |
351 | join(FILE2, FILE2 SUFFIX, FILE2 BACKUP); | |
352 | join(FILE3, FILE3 SUFFIX, FILE3 BACKUP); | |
353 | join(FILE4, FILE4 SUFFIX, FILE4 BACKUP); | |
354 | #else | |
355 | join("test", "test.new", "test.old"); | |
356 | #endif | |
357 | return 0; | |
358 | } |