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f342fce2 | 1 | /* -*-c-*- |
2 | * | |
ed04d555 | 3 | * $Id$ |
f342fce2 | 4 | * |
5 | * Lock a file, run a program | |
6 | * | |
7 | * (c) 2003 Mark Wooding | |
8 | */ | |
9 | ||
841e5aca | 10 | /*----- Licensing notice --------------------------------------------------* |
f342fce2 | 11 | * |
12 | * This file is part of the Toys utilties collection. | |
13 | * | |
14 | * Toys is free software; you can redistribute it and/or modify | |
15 | * it under the terms of the GNU General Public License as published by | |
16 | * the Free Software Foundation; either version 2 of the License, or | |
17 | * (at your option) any later version. | |
841e5aca | 18 | * |
f342fce2 | 19 | * Toys is distributed in the hope that it will be useful, |
20 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
21 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
22 | * GNU General Public License for more details. | |
841e5aca | 23 | * |
f342fce2 | 24 | * You should have received a copy of the GNU General Public License |
25 | * along with Toys; if not, write to the Free Software Foundation, | |
26 | * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. | |
27 | */ | |
28 | ||
f342fce2 | 29 | /*----- Header files ------------------------------------------------------*/ |
30 | ||
31 | #include <errno.h> | |
32 | #include <setjmp.h> | |
33 | #include <signal.h> | |
34 | #include <stdio.h> | |
35 | #include <stdlib.h> | |
36 | #include <string.h> | |
ed04d555 | 37 | #include <time.h> |
f342fce2 | 38 | |
39 | #include <sys/types.h> | |
40 | #include <sys/time.h> | |
41 | #include <unistd.h> | |
42 | #include <fcntl.h> | |
43 | #include <sys/wait.h> | |
44 | ||
45 | #include <mLib/mdwopt.h> | |
46 | #include <mLib/quis.h> | |
47 | #include <mLib/report.h> | |
48 | ||
49 | /*----- Static variables --------------------------------------------------*/ | |
50 | ||
51 | static jmp_buf jmp; | |
52 | ||
53 | /*----- Main code ---------------------------------------------------------*/ | |
54 | ||
55 | static void alrm(int s) { longjmp(jmp, 1); } | |
56 | ||
57 | static void usage(FILE *fp) | |
58 | { | |
59 | pquis(fp, | |
60 | "Usage: $ [-cfwx] [-p REALPROG] [-t TIMEOUT] FILE PROG ARGS...\n"); | |
61 | } | |
62 | ||
63 | static void version(FILE *fp) | |
64 | { | |
5b11bb47 | 65 | pquis(fp, "$ (version " VERSION ")\n"); |
f342fce2 | 66 | } |
67 | ||
68 | static void help(FILE *fp) | |
69 | { | |
70 | version(fp); | |
71 | putchar('\n'); | |
72 | usage(fp); | |
73 | pquis(fp, "\n\ | |
74 | Lock FILE and run PROG, passing ARGS. Options are:\n\ | |
75 | \n\ | |
76 | -h, --help Show this help message.\n\ | |
77 | -v, --version Show version string.\n\ | |
78 | -u, --usage Show terse usage summary.\n\ | |
79 | \n\ | |
80 | -c, --[no-]create Create FILE if it doesn't exist [default: on].\n\ | |
81 | -f, --[no-]fail Fail if the file is already locked [default: off].\n\ | |
82 | -w, --[no-]wait Wait for the lock to be available [default: off].\n\ | |
83 | -x, --[no-]exclusive Get an exclusive (writer) lock [default: on].\n\ | |
84 | -p, --program=REALPROG Run REALPROG instead of PROG.\n\ | |
85 | -t, --timeout=TIME Wait for TIME for lock to become available.\n\ | |
86 | "); | |
87 | } | |
88 | ||
89 | int main(int argc, char *argv[]) | |
90 | { | |
91 | const char *file = 0; | |
92 | const char *prog = 0; | |
93 | char *const *av; | |
94 | void (*oalrm)(int) = 0; | |
95 | int fd; | |
96 | struct flock l; | |
97 | char *p; | |
98 | int t = -1; | |
1ad88a2f | 99 | unsigned int ot = 0; |
f342fce2 | 100 | time_t nt; |
101 | pid_t kid; | |
102 | int st; | |
103 | ||
104 | #define f_bogus 1u | |
105 | #define f_wait 2u | |
106 | #define f_fail 4u | |
107 | #define f_create 8u | |
108 | #define f_excl 16u | |
109 | ||
110 | unsigned f = f_create | f_excl; | |
111 | ||
112 | ego(argv[0]); | |
113 | ||
114 | for (;;) { | |
115 | static const struct option opts[] = { | |
116 | { "help", 0, 0, 'h' }, | |
117 | { "version", 0, 0, 'v' }, | |
118 | { "usage", 0, 0, 'u' }, | |
119 | { "wait", OPTF_NEGATE, 0, 'w' }, | |
120 | { "fail", OPTF_NEGATE, 0, 'f' }, | |
121 | { "create", OPTF_NEGATE, 0, 'c' }, | |
122 | { "program", OPTF_ARGREQ, 0, 'p' }, | |
123 | { "timeout", OPTF_ARGREQ, 0, 't' }, | |
124 | { "exclusive", OPTF_NEGATE, 0, 'x' }, | |
125 | { 0, 0, 0, 0 } | |
126 | }; | |
127 | ||
128 | int i = mdwopt(argc, argv, "-hvuw+f+c+x+p:t:", opts, | |
129 | 0, 0, OPTF_NEGATION); | |
130 | if (i < 0) | |
131 | break; | |
132 | switch (i) { | |
133 | case 'h': | |
134 | help(stdout); | |
135 | exit(0); | |
136 | case 'v': | |
137 | version(stdout); | |
138 | exit(0); | |
139 | case 'u': | |
140 | usage(stdout); | |
141 | exit(0); | |
142 | case 'w': | |
143 | f |= f_wait; | |
144 | break; | |
145 | case 'w' | OPTF_NEGATED: | |
146 | f &= ~f_wait; | |
147 | break; | |
148 | case 'f': | |
149 | f |= f_fail; | |
150 | break; | |
151 | case 'f' | OPTF_NEGATED: | |
152 | f &= ~f_fail; | |
153 | break; | |
154 | case 'c': | |
155 | f |= f_create; | |
156 | break; | |
157 | case 'c' | OPTF_NEGATED: | |
158 | f &= ~f_create; | |
159 | break; | |
160 | case 'x': | |
161 | f |= f_excl; | |
162 | break; | |
163 | case 'x' | OPTF_NEGATED: | |
164 | f &= ~f_excl; | |
165 | break; | |
166 | case 't': | |
167 | errno = 0; | |
168 | t = strtol(optarg, &p, 0); | |
169 | switch (*p) { | |
170 | case 'd': t *= 24; | |
171 | case 'h': t *= 60; | |
172 | case 'm': t *= 60; | |
173 | case 's': p++; | |
174 | case 0: break; | |
175 | default: die(111, "unknown time unit `%c'", *p); | |
176 | } | |
177 | if (*p || t < 0 || errno) | |
178 | die(111, "bad time value `%s'", optarg); | |
179 | f |= f_wait; | |
180 | break; | |
181 | case 'p': | |
182 | prog = optarg; | |
183 | break; | |
184 | case 0: | |
185 | if (file) { | |
186 | optind--; | |
187 | goto doneopts; | |
188 | } | |
189 | file = optarg; | |
190 | break; | |
191 | default: | |
192 | f |= f_bogus; | |
193 | break; | |
194 | } | |
195 | } | |
196 | ||
197 | doneopts: | |
198 | if (f & f_bogus || argc - optind < 1) { | |
199 | usage(stderr); | |
200 | exit(EXIT_FAILURE); | |
201 | } | |
202 | ||
203 | av = &argv[optind]; | |
204 | if (!prog) | |
205 | prog = av[0]; | |
206 | if ((fd = open(file, | |
207 | ((f & f_create ? O_CREAT : 0) | | |
208 | (f & f_excl ? O_RDWR : O_RDONLY)), 0666)) < 0) | |
209 | die(111, "error opening `%s': %s", file, strerror(errno)); | |
210 | l.l_type = f & f_excl ? F_WRLCK : F_RDLCK; | |
211 | l.l_whence = SEEK_SET; | |
212 | l.l_start = 0; | |
213 | l.l_len = 0; | |
214 | nt = time(0); | |
215 | if (setjmp(jmp)) { | |
216 | errno = EAGAIN; | |
217 | nt = t; | |
218 | } else { | |
219 | ot = alarm(0); | |
220 | oalrm = signal(SIGALRM, alrm); | |
221 | if (t >= 0) | |
222 | alarm(t); | |
223 | if (fcntl(fd, f & f_wait ? F_SETLKW : F_SETLK, &l) >= 0) | |
224 | errno = 0; | |
225 | } | |
226 | signal(SIGALRM, oalrm); | |
76e174aa MW |
227 | if (!ot) |
228 | alarm(0); | |
229 | else { | |
f342fce2 | 230 | nt = time(0) - nt; |
231 | if (nt > ot) | |
232 | raise(SIGALRM); | |
233 | else | |
234 | alarm(ot - nt); | |
235 | } | |
236 | if (errno && | |
237 | ((errno != EAGAIN && errno != EWOULDBLOCK && errno != EACCES) || | |
238 | (f & f_fail))) | |
239 | die(111, "error locking `%s': %s", file, strerror(errno)); | |
240 | if (errno) | |
241 | exit(0); | |
242 | ||
243 | if ((kid = fork()) < 0) | |
244 | die(111, "error from fork: %s", strerror(errno)); | |
245 | if (!kid) { | |
246 | close(fd); | |
247 | execvp(prog, av); | |
248 | die(111, "couldn't exec `%s': %s", prog, strerror(errno)); | |
249 | } | |
250 | if (waitpid(kid, &st, 0) < 0) | |
251 | die(EXIT_FAILURE, "error from wait: %s", strerror(errno)); | |
252 | l.l_type = F_UNLCK; | |
253 | l.l_whence = SEEK_SET; | |
254 | l.l_start = 0; | |
255 | l.l_len = 0; | |
256 | fcntl(fd, F_SETLK, &l); | |
257 | close(fd); | |
258 | if (WIFEXITED(st)) | |
259 | exit(WEXITSTATUS(st)); | |
260 | else | |
261 | exit(255); | |
262 | } | |
263 | ||
264 | /*----- That's all, folks -------------------------------------------------*/ |