Commit | Line | Data |
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f342fce2 | 1 | /* -*-c-*- |
2 | * | |
f342fce2 | 3 | * Lock a file, run a program |
4 | * | |
5 | * (c) 2003 Mark Wooding | |
6 | */ | |
7 | ||
841e5aca | 8 | /*----- Licensing notice --------------------------------------------------* |
f342fce2 | 9 | * |
10 | * This file is part of the Toys utilties collection. | |
11 | * | |
12 | * Toys is free software; you can redistribute it and/or modify | |
13 | * it under the terms of the GNU General Public License as published by | |
14 | * the Free Software Foundation; either version 2 of the License, or | |
15 | * (at your option) any later version. | |
841e5aca | 16 | * |
f342fce2 | 17 | * Toys is distributed in the hope that it will be useful, |
18 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
19 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
20 | * GNU General Public License for more details. | |
841e5aca | 21 | * |
f342fce2 | 22 | * You should have received a copy of the GNU General Public License |
23 | * along with Toys; if not, write to the Free Software Foundation, | |
24 | * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. | |
25 | */ | |
26 | ||
f342fce2 | 27 | /*----- Header files ------------------------------------------------------*/ |
28 | ||
29 | #include <errno.h> | |
30 | #include <setjmp.h> | |
31 | #include <signal.h> | |
32 | #include <stdio.h> | |
33 | #include <stdlib.h> | |
34 | #include <string.h> | |
ed04d555 | 35 | #include <time.h> |
f342fce2 | 36 | |
37 | #include <sys/types.h> | |
38 | #include <sys/time.h> | |
39 | #include <unistd.h> | |
40 | #include <fcntl.h> | |
41 | #include <sys/wait.h> | |
42 | ||
43 | #include <mLib/mdwopt.h> | |
44 | #include <mLib/quis.h> | |
45 | #include <mLib/report.h> | |
46 | ||
47 | /*----- Static variables --------------------------------------------------*/ | |
48 | ||
49 | static jmp_buf jmp; | |
50 | ||
51 | /*----- Main code ---------------------------------------------------------*/ | |
52 | ||
53 | static void alrm(int s) { longjmp(jmp, 1); } | |
54 | ||
55 | static void usage(FILE *fp) | |
56 | { | |
57 | pquis(fp, | |
58 | "Usage: $ [-cfwx] [-p REALPROG] [-t TIMEOUT] FILE PROG ARGS...\n"); | |
59 | } | |
60 | ||
61 | static void version(FILE *fp) | |
c9a19878 | 62 | { pquis(fp, "$ (version " VERSION ")\n"); } |
f342fce2 | 63 | |
64 | static void help(FILE *fp) | |
65 | { | |
66 | version(fp); | |
67 | putchar('\n'); | |
68 | usage(fp); | |
69 | pquis(fp, "\n\ | |
70 | Lock FILE and run PROG, passing ARGS. Options are:\n\ | |
71 | \n\ | |
72 | -h, --help Show this help message.\n\ | |
73 | -v, --version Show version string.\n\ | |
74 | -u, --usage Show terse usage summary.\n\ | |
75 | \n\ | |
76 | -c, --[no-]create Create FILE if it doesn't exist [default: on].\n\ | |
77 | -f, --[no-]fail Fail if the file is already locked [default: off].\n\ | |
78 | -w, --[no-]wait Wait for the lock to be available [default: off].\n\ | |
79 | -x, --[no-]exclusive Get an exclusive (writer) lock [default: on].\n\ | |
80 | -p, --program=REALPROG Run REALPROG instead of PROG.\n\ | |
81 | -t, --timeout=TIME Wait for TIME for lock to become available.\n\ | |
82 | "); | |
83 | } | |
84 | ||
85 | int main(int argc, char *argv[]) | |
86 | { | |
87 | const char *file = 0; | |
88 | const char *prog = 0; | |
89 | char *const *av; | |
90 | void (*oalrm)(int) = 0; | |
91 | int fd; | |
92 | struct flock l; | |
93 | char *p; | |
94 | int t = -1; | |
1ad88a2f | 95 | unsigned int ot = 0; |
f342fce2 | 96 | time_t nt; |
97 | pid_t kid; | |
98 | int st; | |
99 | ||
100 | #define f_bogus 1u | |
101 | #define f_wait 2u | |
102 | #define f_fail 4u | |
103 | #define f_create 8u | |
104 | #define f_excl 16u | |
105 | ||
106 | unsigned f = f_create | f_excl; | |
107 | ||
108 | ego(argv[0]); | |
109 | ||
110 | for (;;) { | |
111 | static const struct option opts[] = { | |
112 | { "help", 0, 0, 'h' }, | |
113 | { "version", 0, 0, 'v' }, | |
114 | { "usage", 0, 0, 'u' }, | |
115 | { "wait", OPTF_NEGATE, 0, 'w' }, | |
116 | { "fail", OPTF_NEGATE, 0, 'f' }, | |
117 | { "create", OPTF_NEGATE, 0, 'c' }, | |
118 | { "program", OPTF_ARGREQ, 0, 'p' }, | |
119 | { "timeout", OPTF_ARGREQ, 0, 't' }, | |
120 | { "exclusive", OPTF_NEGATE, 0, 'x' }, | |
121 | { 0, 0, 0, 0 } | |
122 | }; | |
123 | ||
124 | int i = mdwopt(argc, argv, "-hvuw+f+c+x+p:t:", opts, | |
125 | 0, 0, OPTF_NEGATION); | |
c9a19878 | 126 | if (i < 0) break; |
f342fce2 | 127 | switch (i) { |
c9a19878 MW |
128 | case 'h': help(stdout); exit(0); |
129 | case 'v': version(stdout); exit(0); | |
130 | case 'u': usage(stdout); exit(0); | |
131 | case 'w': f |= f_wait; break; | |
132 | case 'w' | OPTF_NEGATED: f &= ~f_wait; break; | |
133 | case 'f': f |= f_fail; break; | |
134 | case 'f' | OPTF_NEGATED: f &= ~f_fail; break; | |
135 | case 'c': f |= f_create; break; | |
136 | case 'c' | OPTF_NEGATED: f &= ~f_create; break; | |
137 | case 'x': f |= f_excl; break; | |
138 | case 'x' | OPTF_NEGATED: f &= ~f_excl; break; | |
f342fce2 | 139 | case 't': |
140 | errno = 0; | |
141 | t = strtol(optarg, &p, 0); | |
142 | switch (*p) { | |
143 | case 'd': t *= 24; | |
144 | case 'h': t *= 60; | |
145 | case 'm': t *= 60; | |
146 | case 's': p++; | |
147 | case 0: break; | |
148 | default: die(111, "unknown time unit `%c'", *p); | |
149 | } | |
c9a19878 | 150 | if (*p || t < 0 || errno) die(111, "bad time value `%s'", optarg); |
f342fce2 | 151 | f |= f_wait; |
152 | break; | |
c9a19878 | 153 | case 'p': prog = optarg; break; |
f342fce2 | 154 | case 0: |
c9a19878 | 155 | if (file) { optind--; goto doneopts; } |
f342fce2 | 156 | file = optarg; |
157 | break; | |
c9a19878 | 158 | default: f |= f_bogus; break; |
f342fce2 | 159 | } |
160 | } | |
161 | ||
162 | doneopts: | |
163 | if (f & f_bogus || argc - optind < 1) { | |
164 | usage(stderr); | |
165 | exit(EXIT_FAILURE); | |
166 | } | |
167 | ||
168 | av = &argv[optind]; | |
c9a19878 | 169 | if (!prog) prog = av[0]; |
f342fce2 | 170 | if ((fd = open(file, |
171 | ((f & f_create ? O_CREAT : 0) | | |
172 | (f & f_excl ? O_RDWR : O_RDONLY)), 0666)) < 0) | |
173 | die(111, "error opening `%s': %s", file, strerror(errno)); | |
174 | l.l_type = f & f_excl ? F_WRLCK : F_RDLCK; | |
175 | l.l_whence = SEEK_SET; | |
176 | l.l_start = 0; | |
177 | l.l_len = 0; | |
178 | nt = time(0); | |
179 | if (setjmp(jmp)) { | |
180 | errno = EAGAIN; | |
181 | nt = t; | |
182 | } else { | |
183 | ot = alarm(0); | |
184 | oalrm = signal(SIGALRM, alrm); | |
c9a19878 MW |
185 | if (t >= 0) alarm(t); |
186 | if (fcntl(fd, f & f_wait ? F_SETLKW : F_SETLK, &l) >= 0) errno = 0; | |
f342fce2 | 187 | } |
188 | signal(SIGALRM, oalrm); | |
76e174aa MW |
189 | if (!ot) |
190 | alarm(0); | |
191 | else { | |
f342fce2 | 192 | nt = time(0) - nt; |
c9a19878 MW |
193 | if (nt > ot) raise(SIGALRM); |
194 | else alarm(ot - nt); | |
f342fce2 | 195 | } |
196 | if (errno && | |
197 | ((errno != EAGAIN && errno != EWOULDBLOCK && errno != EACCES) || | |
198 | (f & f_fail))) | |
199 | die(111, "error locking `%s': %s", file, strerror(errno)); | |
c9a19878 | 200 | if (errno) exit(0); |
f342fce2 | 201 | |
c9a19878 | 202 | if ((kid = fork()) < 0) die(111, "error from fork: %s", strerror(errno)); |
f342fce2 | 203 | if (!kid) { |
204 | close(fd); | |
205 | execvp(prog, av); | |
206 | die(111, "couldn't exec `%s': %s", prog, strerror(errno)); | |
207 | } | |
208 | if (waitpid(kid, &st, 0) < 0) | |
209 | die(EXIT_FAILURE, "error from wait: %s", strerror(errno)); | |
210 | l.l_type = F_UNLCK; | |
211 | l.l_whence = SEEK_SET; | |
212 | l.l_start = 0; | |
213 | l.l_len = 0; | |
214 | fcntl(fd, F_SETLK, &l); | |
215 | close(fd); | |
c9a19878 MW |
216 | if (WIFEXITED(st)) exit(WEXITSTATUS(st)); |
217 | else exit(255); | |
f342fce2 | 218 | } |
219 | ||
220 | /*----- That's all, folks -------------------------------------------------*/ |