OpenWrt – Blame information for rev 2

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1 office 1 /* ----------------------------------------------------------------------- *
2 *
3 * Copyright 2003-2005 H. Peter Anvin - All Rights Reserved
4 *
5 * Permission is hereby granted, free of charge, to any person
6 * obtaining a copy of this software and associated documentation
7 * files (the "Software"), to deal in the Software without
8 * restriction, including without limitation the rights to use,
9 * copy, modify, merge, publish, distribute, sublicense, and/or
10 * sell copies of the Software, and to permit persons to whom
11 * the Software is furnished to do so, subject to the following
12 * conditions:
13 *
14 * The above copyright notice and this permission notice shall
15 * be included in all copies or substantial portions of the Software.
16 *
17 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
18 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
19 * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
20 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
21 * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
22 * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
23 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
24 * OTHER DEALINGS IN THE SOFTWARE.
25 *
26 * ----------------------------------------------------------------------- */
27  
28 #include <errno.h>
29 #include <stdio.h>
30 #include <stdlib.h>
31 #include <unistd.h>
32 #include <getopt.h>
33 #include <signal.h>
34 #include <ctype.h>
35 #include <string.h>
36 #include <paths.h>
37 #include <sysexits.h>
38 #include <sys/types.h>
39 #include <sys/file.h>
40 #include <sys/time.h>
41 #include <sys/wait.h>
42 #include <fcntl.h>
43  
44 #define PACKAGE_STRING "util-linux-ng 2.18"
45 #define _(x) (x)
46  
47 static const struct option long_options[] = {
48 { "shared", 0, NULL, 's' },
49 { "exclusive", 0, NULL, 'x' },
50 { "unlock", 0, NULL, 'u' },
51 { "nonblocking", 0, NULL, 'n' },
52 { "nb", 0, NULL, 'n' },
53 { "timeout", 1, NULL, 'w' },
54 { "wait", 1, NULL, 'w' },
55 { "close", 0, NULL, 'o' },
56 { "help", 0, NULL, 'h' },
57 { "version", 0, NULL, 'V' },
58 { 0, 0, 0, 0 }
59 };
60  
61 const char *program;
62  
63 static void usage(int ex)
64 {
65 fputs("flock (" PACKAGE_STRING ")\n", stderr);
66 fprintf(stderr,
67 _("Usage: %1$s [-sxun][-w #] fd#\n"
68 " %1$s [-sxon][-w #] file [-c] command...\n"
69 " %1$s [-sxon][-w #] directory [-c] command...\n"
70 " -s --shared Get a shared lock\n"
71 " -x --exclusive Get an exclusive lock\n"
72 " -u --unlock Remove a lock\n"
73 " -n --nonblock Fail rather than wait\n"
74 " -w --timeout Wait for a limited amount of time\n"
75 " -o --close Close file descriptor before running command\n"
76 " -c --command Run a single command string through the shell\n"
77 " -h --help Display this text\n"
78 " -V --version Display version\n"),
79 program);
80 exit(ex);
81 }
82  
83  
84 static sig_atomic_t timeout_expired = 0;
85  
86 static void timeout_handler(int sig)
87 {
88 (void)sig;
89  
90 timeout_expired = 1;
91 }
92  
93  
94 static char * strtotimeval(const char *str, struct timeval *tv)
95 {
96 char *s;
97 long fs; /* Fractional seconds */
98 int i;
99  
100 tv->tv_sec = strtol(str, &s, 10);
101 fs = 0;
102  
103 if ( *s == '.' ) {
104 s++;
105  
106 for ( i = 0 ; i < 6 ; i++ ) {
107 if ( !isdigit(*s) )
108 break;
109  
110 fs *= 10;
111 fs += *s++ - '0';
112 }
113  
114 for ( ; i < 6; i++ )
115 fs *= 10;
116  
117 while ( isdigit(*s) )
118 s++;
119 }
120  
121 tv->tv_usec = fs;
122 return s;
123 }
124  
125 int main(int argc, char *argv[])
126 {
127 struct itimerval timeout, old_timer;
128 int have_timeout = 0;
129 int type = LOCK_EX;
130 int block = 0;
131 int fd = -1;
132 int opt, ix;
133 int do_close = 0;
134 int err;
135 int status;
136 int open_flags = 0;
137 char *eon;
138 char **cmd_argv = NULL, *sh_c_argv[4];
139 const char *filename = NULL;
140 struct sigaction sa, old_sa;
141  
142 program = argv[0];
143  
144 if ( argc < 2 )
145 usage(EX_USAGE);
146  
147 memset(&timeout, 0, sizeof timeout);
148  
149 optopt = 0;
150 while ( (opt = getopt_long(argc, argv, "+sexnouw:hV?", long_options, &ix)) != EOF ) {
151 switch(opt) {
152 case 's':
153 type = LOCK_SH;
154 break;
155 case 'e':
156 case 'x':
157 type = LOCK_EX;
158 break;
159 case 'u':
160 type = LOCK_UN;
161 break;
162 case 'o':
163 do_close = 1;
164 break;
165 case 'n':
166 block = LOCK_NB;
167 break;
168 case 'w':
169 have_timeout = 1;
170 eon = strtotimeval(optarg, &timeout.it_value);
171 if ( *eon )
172 usage(EX_USAGE);
173 break;
174 case 'V':
175 printf("flock (%s)\n", PACKAGE_STRING);
176 exit(0);
177 default:
178 /* optopt will be set if this was an unrecognized option, i.e. *not* 'h' or '?' */
179 usage(optopt ? EX_USAGE : 0);
180 break;
181 }
182 }
183  
184 if ( argc > optind+1 ) {
185 /* Run command */
186  
187 if ( !strcmp(argv[optind+1], "-c") ||
188 !strcmp(argv[optind+1], "--command") ) {
189  
190 if ( argc != optind+3 ) {
191 fprintf(stderr, _("%s: %s requires exactly one command argument\n"),
192 program, argv[optind+1]);
193 exit(EX_USAGE);
194 }
195  
196 cmd_argv = sh_c_argv;
197  
198 cmd_argv[0] = getenv("SHELL");
199 if ( !cmd_argv[0] || !*cmd_argv[0] )
200 cmd_argv[0] = _PATH_BSHELL;
201  
202 cmd_argv[1] = "-c";
203 cmd_argv[2] = argv[optind+2];
204 cmd_argv[3] = 0;
205 } else {
206 cmd_argv = &argv[optind+1];
207 }
208  
209 filename = argv[optind];
210 fd = open(filename, O_RDONLY|O_NOCTTY|O_CREAT, 0666);
211 /* Linux doesn't like O_CREAT on a directory, even though it should be a
212 no-op */
213 if (fd < 0 && errno == EISDIR)
214 fd = open(filename, O_RDONLY|O_NOCTTY);
215  
216 if ( fd < 0 ) {
217 err = errno;
218 fprintf(stderr, _("%s: cannot open lock file %s: %s\n"),
219 program, argv[optind], strerror(err));
220 exit((err == ENOMEM||err == EMFILE||err == ENFILE) ? EX_OSERR :
221 (err == EROFS||err == ENOSPC) ? EX_CANTCREAT :
222 EX_NOINPUT);
223 }
224  
225 } else if (optind < argc) {
226 /* Use provided file descriptor */
227  
228 fd = (int)strtol(argv[optind], &eon, 10);
229 if ( *eon || !argv[optind] ) {
230 fprintf(stderr, _("%s: bad number: %s\n"), program, argv[optind]);
231 exit(EX_USAGE);
232 }
233  
234 } else {
235 /* Bad options */
236  
237 fprintf(stderr, _("%s: requires file descriptor, file or directory\n"),
238 program);
239 exit(EX_USAGE);
240 }
241  
242  
243 if ( have_timeout ) {
244 if ( timeout.it_value.tv_sec == 0 &&
245 timeout.it_value.tv_usec == 0 ) {
246 /* -w 0 is equivalent to -n; this has to be special-cased
247 because setting an itimer to zero means disabled! */
248  
249 have_timeout = 0;
250 block = LOCK_NB;
251 } else {
252 memset(&sa, 0, sizeof sa);
253  
254 sa.sa_handler = timeout_handler;
255 sa.sa_flags = SA_RESETHAND;
256 sigaction(SIGALRM, &sa, &old_sa);
257  
258 setitimer(ITIMER_REAL, &timeout, &old_timer);
259 }
260 }
261  
262 while ( flock(fd, type|block) ) {
263 switch( (err = errno) ) {
264 case EWOULDBLOCK: /* -n option set and failed to lock */
265 exit(1);
266 case EINTR: /* Signal received */
267 if ( timeout_expired )
268 exit(1); /* -w option set and failed to lock */
269 continue; /* otherwise try again */
270 case EBADF: /* since Linux 3.4 (commit 55725513) */
271 /* Probably NFSv4 where flock() is emulated by fcntl().
272 * Let's try to reopen in read-write mode.
273 */
274 if (!(open_flags & O_RDWR) &&
275 type != LOCK_SH &&
276 filename &&
277 access(filename, R_OK | W_OK) == 0) {
278  
279 close(fd);
280 open_flags = O_RDWR;
281 fd = open(filename, open_flags);
282 break;
283 }
284 /* go through */
285 default: /* Other errors */
286 if ( filename )
287 fprintf(stderr, "%s: %s: %s\n", program, filename, strerror(err));
288 else
289 fprintf(stderr, "%s: %d: %s\n", program, fd, strerror(err));
290 exit((err == ENOLCK||err == ENOMEM) ? EX_OSERR : EX_DATAERR);
291 }
292 }
293  
294 if ( have_timeout ) {
295 setitimer(ITIMER_REAL, &old_timer, NULL); /* Cancel itimer */
296 sigaction(SIGALRM, &old_sa, NULL); /* Cancel signal handler */
297 }
298  
299 status = 0;
300  
301 if ( cmd_argv ) {
302 pid_t w, f;
303  
304 /* Clear any inherited settings */
305 signal(SIGCHLD, SIG_DFL);
306 f = fork();
307  
308 if ( f < 0 ) {
309 err = errno;
310 fprintf(stderr, _("%s: fork failed: %s\n"), program, strerror(err));
311 exit(EX_OSERR);
312 } else if ( f == 0 ) {
313 if ( do_close )
314 close(fd);
315 err = errno;
316 execvp(cmd_argv[0], cmd_argv);
317 /* execvp() failed */
318 fprintf(stderr, "%s: %s: %s\n", program, cmd_argv[0], strerror(err));
319 _exit((err == ENOMEM) ? EX_OSERR: EX_UNAVAILABLE);
320 } else {
321 do {
322 w = waitpid(f, &status, 0);
323 if (w == -1 && errno != EINTR)
324 break;
325 } while ( w != f );
326  
327 if (w == -1) {
328 err = errno;
329 status = EXIT_FAILURE;
330 fprintf(stderr, "%s: waitpid failed: %s\n", program, strerror(err));
331 } else if ( WIFEXITED(status) )
332 status = WEXITSTATUS(status);
333 else if ( WIFSIGNALED(status) )
334 status = WTERMSIG(status) + 128;
335 else
336 status = EX_OSERR; /* WTF? */
337 }
338 }
339  
340 return status;
341 }
342