--- /dev/null
+/* -*-c-*-
+ *
+ * $Id: locking.c,v 1.1 2003/10/09 15:05:34 mdw Exp $
+ *
+ * Lock a file, run a program
+ *
+ * (c) 2003 Mark Wooding
+ */
+
+/*----- Licensing notice --------------------------------------------------*
+ *
+ * This file is part of the Toys utilties collection.
+ *
+ * Toys is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * Toys is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Toys; if not, write to the Free Software Foundation,
+ * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ */
+
+/*----- Revision history --------------------------------------------------*
+ *
+ * $Log: locking.c,v $
+ * Revision 1.1 2003/10/09 15:05:34 mdw
+ * Lots of stuff.
+ *
+ * Revision 1.3 2003/09/24 14:58:08 mdw
+ * Fix options parsing again.
+ *
+ * Revision 1.2 2003/09/24 14:14:03 mdw
+ * Fix option handling behaviour.
+ *
+ * Revision 1.1 2003/05/11 13:30:04 mdw
+ * Initial checkin.
+ *
+ */
+
+/*----- Header files ------------------------------------------------------*/
+
+#include <errno.h>
+#include <setjmp.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <sys/types.h>
+#include <sys/time.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <sys/wait.h>
+
+#include <mLib/mdwopt.h>
+#include <mLib/quis.h>
+#include <mLib/report.h>
+
+/*----- Static variables --------------------------------------------------*/
+
+static jmp_buf jmp;
+
+/*----- Main code ---------------------------------------------------------*/
+
+static void alrm(int s) { longjmp(jmp, 1); }
+
+static void usage(FILE *fp)
+{
+ pquis(fp,
+ "Usage: $ [-cfwx] [-p REALPROG] [-t TIMEOUT] FILE PROG ARGS...\n");
+}
+
+static void version(FILE *fp)
+{
+ pquis(fp, "$ (toys, version " VERSION "\n");
+}
+
+static void help(FILE *fp)
+{
+ version(fp);
+ putchar('\n');
+ usage(fp);
+ pquis(fp, "\n\
+Lock FILE and run PROG, passing ARGS. Options are:\n\
+\n\
+-h, --help Show this help message.\n\
+-v, --version Show version string.\n\
+-u, --usage Show terse usage summary.\n\
+\n\
+-c, --[no-]create Create FILE if it doesn't exist [default: on].\n\
+-f, --[no-]fail Fail if the file is already locked [default: off].\n\
+-w, --[no-]wait Wait for the lock to be available [default: off].\n\
+-x, --[no-]exclusive Get an exclusive (writer) lock [default: on].\n\
+-p, --program=REALPROG Run REALPROG instead of PROG.\n\
+-t, --timeout=TIME Wait for TIME for lock to become available.\n\
+");
+}
+
+int main(int argc, char *argv[])
+{
+ const char *file = 0;
+ const char *prog = 0;
+ char *const *av;
+ void (*oalrm)(int) = 0;
+ int fd;
+ struct flock l;
+ char *p;
+ int t = -1;
+ unsigned int ot;
+ time_t nt;
+ pid_t kid;
+ int st;
+
+#define f_bogus 1u
+#define f_wait 2u
+#define f_fail 4u
+#define f_create 8u
+#define f_excl 16u
+
+ unsigned f = f_create | f_excl;
+
+ ego(argv[0]);
+
+ for (;;) {
+ static const struct option opts[] = {
+ { "help", 0, 0, 'h' },
+ { "version", 0, 0, 'v' },
+ { "usage", 0, 0, 'u' },
+ { "wait", OPTF_NEGATE, 0, 'w' },
+ { "fail", OPTF_NEGATE, 0, 'f' },
+ { "create", OPTF_NEGATE, 0, 'c' },
+ { "program", OPTF_ARGREQ, 0, 'p' },
+ { "timeout", OPTF_ARGREQ, 0, 't' },
+ { "exclusive", OPTF_NEGATE, 0, 'x' },
+ { 0, 0, 0, 0 }
+ };
+
+ int i = mdwopt(argc, argv, "-hvuw+f+c+x+p:t:", opts,
+ 0, 0, OPTF_NEGATION);
+ if (i < 0)
+ break;
+ switch (i) {
+ case 'h':
+ help(stdout);
+ exit(0);
+ case 'v':
+ version(stdout);
+ exit(0);
+ case 'u':
+ usage(stdout);
+ exit(0);
+ case 'w':
+ f |= f_wait;
+ break;
+ case 'w' | OPTF_NEGATED:
+ f &= ~f_wait;
+ break;
+ case 'f':
+ f |= f_fail;
+ break;
+ case 'f' | OPTF_NEGATED:
+ f &= ~f_fail;
+ break;
+ case 'c':
+ f |= f_create;
+ break;
+ case 'c' | OPTF_NEGATED:
+ f &= ~f_create;
+ break;
+ case 'x':
+ f |= f_excl;
+ break;
+ case 'x' | OPTF_NEGATED:
+ f &= ~f_excl;
+ break;
+ case 't':
+ errno = 0;
+ t = strtol(optarg, &p, 0);
+ switch (*p) {
+ case 'd': t *= 24;
+ case 'h': t *= 60;
+ case 'm': t *= 60;
+ case 's': p++;
+ case 0: break;
+ default: die(111, "unknown time unit `%c'", *p);
+ }
+ if (*p || t < 0 || errno)
+ die(111, "bad time value `%s'", optarg);
+ f |= f_wait;
+ break;
+ case 'p':
+ prog = optarg;
+ break;
+ case 0:
+ if (file) {
+ optind--;
+ goto doneopts;
+ }
+ file = optarg;
+ break;
+ default:
+ f |= f_bogus;
+ break;
+ }
+ }
+
+doneopts:
+ if (f & f_bogus || argc - optind < 1) {
+ usage(stderr);
+ exit(EXIT_FAILURE);
+ }
+
+ av = &argv[optind];
+ if (!prog)
+ prog = av[0];
+ if ((fd = open(file,
+ ((f & f_create ? O_CREAT : 0) |
+ (f & f_excl ? O_RDWR : O_RDONLY)), 0666)) < 0)
+ die(111, "error opening `%s': %s", file, strerror(errno));
+ l.l_type = f & f_excl ? F_WRLCK : F_RDLCK;
+ l.l_whence = SEEK_SET;
+ l.l_start = 0;
+ l.l_len = 0;
+ nt = time(0);
+ if (setjmp(jmp)) {
+ errno = EAGAIN;
+ nt = t;
+ } else {
+ ot = alarm(0);
+ oalrm = signal(SIGALRM, alrm);
+ if (t >= 0)
+ alarm(t);
+ if (fcntl(fd, f & f_wait ? F_SETLKW : F_SETLK, &l) >= 0)
+ errno = 0;
+ }
+ signal(SIGALRM, oalrm);
+ if (ot) {
+ nt = time(0) - nt;
+ if (nt > ot)
+ raise(SIGALRM);
+ else
+ alarm(ot - nt);
+ }
+ if (errno &&
+ ((errno != EAGAIN && errno != EWOULDBLOCK && errno != EACCES) ||
+ (f & f_fail)))
+ die(111, "error locking `%s': %s", file, strerror(errno));
+ if (errno)
+ exit(0);
+
+ if ((kid = fork()) < 0)
+ die(111, "error from fork: %s", strerror(errno));
+ if (!kid) {
+ close(fd);
+ execvp(prog, av);
+ die(111, "couldn't exec `%s': %s", prog, strerror(errno));
+ }
+ if (waitpid(kid, &st, 0) < 0)
+ die(EXIT_FAILURE, "error from wait: %s", strerror(errno));
+ l.l_type = F_UNLCK;
+ l.l_whence = SEEK_SET;
+ l.l_start = 0;
+ l.l_len = 0;
+ fcntl(fd, F_SETLK, &l);
+ close(fd);
+ if (WIFEXITED(st))
+ exit(WEXITSTATUS(st));
+ else
+ exit(255);
+}
+
+/*----- That's all, folks -------------------------------------------------*/
~mdw / misc / blobdiff