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author | Caleb Tennis <caleb@gentoo.org> | 2008-02-05 18:22:38 +0000 |
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committer | Caleb Tennis <caleb@gentoo.org> | 2008-02-05 18:22:38 +0000 |
commit | cc18370fe4422dd4f5f6cc050d17b2c31d0de4ea (patch) | |
tree | bd1ba3730a8ca0295a06a6ca1d012874cf91365e /dev-util/lockrun/files | |
parent | Stable for HPPA (bug #208929). Fixed an unquoted variable. (diff) | |
download | gentoo-2-cc18370fe4422dd4f5f6cc050d17b2c31d0de4ea.tar.gz gentoo-2-cc18370fe4422dd4f5f6cc050d17b2c31d0de4ea.tar.bz2 gentoo-2-cc18370fe4422dd4f5f6cc050d17b2c31d0de4ea.zip |
Initial import
(Portage version: 2.1.4.1)
Diffstat (limited to 'dev-util/lockrun/files')
-rw-r--r-- | dev-util/lockrun/files/lockrun.c | 275 |
1 files changed, 275 insertions, 0 deletions
diff --git a/dev-util/lockrun/files/lockrun.c b/dev-util/lockrun/files/lockrun.c new file mode 100644 index 000000000000..bccc0db7bcb7 --- /dev/null +++ b/dev-util/lockrun/files/lockrun.c @@ -0,0 +1,275 @@ +/* + * $Id: lockrun.c,v 1.1 2008/02/05 18:22:38 caleb Exp $ + * + * written by : Stephen J. Friedl + * Software Consultant + * steve@unixwiz.net + * http://www.unixwiz.net/tools/ + * + * =================================================================== + * ======== This software is in the public domain, and can be ======== + * ======== used by anybody for any purpose ======== + * =================================================================== + * + * Lockrun: This program is used to launch a program out with a lockout + * so that only one can run at a time. It's mainly intended for use out + * of cron so that our five-minute running jobs which run long don't get + * walked on. We find this a *lot* with Cacti jobs which just get hung + * up: it's better to miss a polling period than to stack them up and + * slow each other down. + * + * So we use a file which is used for locking: this program attempts to + * lock the file, and if the lock exists, we have to either exit with + * an error, or wait for it to release. + * + * lockrun --lockfile=FILE -- my command here + * + * COMMAND LINE + * ------------ + * + * --lockfile=F + * + * Specify the name of a file which is used for locking. The file is + * created if necessary (with mode 0666), and no I/O of any kind is + * done. The file is never removed. + * + * --maxtime=N + * + * The script being controlled should run for no more than <N> seconds, + * and if it's beyond that time, we should report it to the standard + * error (which probably gets routed to the user via cron's email). + * + * --wait + * + * When a lock is hit, we normally exit with error, but --wait causes + * it to loop until the lock is released. + * + * --verbose + * + * Show a bit more runtime debugging. + * + * -- + * + * Mark the end of the options: the command to run follows. + * + */ + +#include <stdio.h> +#include <stdarg.h> +#include <errno.h> +#include <stdlib.h> +#include <string.h> +#include <fcntl.h> +#include <unistd.h> +#include <time.h> +#include <sys/types.h> +#include <sys/wait.h> +#include <sys/file.h> + +#ifndef __GNUC__ +# define __attribute__(x) /* nothing */ +#endif + + +#define STRMATCH(a,b) (strcmp((a),(b)) == 0) + +#define UNUSED_PARAMETER(v) ((void)(v)) + +#define TRUE 1 +#define FALSE 0 + +static const char *lockfile = 0; +static int wait_for_lock = FALSE; +static mode_t openmode = 0666; +static int sleeptime = 10; /* seconds */ +static int Verbose = FALSE; +static int Maxtime = 0; + +static char *getarg(char *opt, char ***pargv); + +static void die(const char *format, ...) + __attribute__((noreturn)) + __attribute__((format(printf, 1, 2))); + +int main(int argc, char **argv) +{ + char *Argv0 = *argv; + int rc; + int lfd; + pid_t childpid; + time_t starttime; + + UNUSED_PARAMETER(argc); + + time(&starttime); + + for ( argv++ ; *argv ; argv++ ) + { + char *arg = *argv; + char *opt = strchr(arg, '='); + + /* the -- token marks the end of the list */ + + if ( strcmp(*argv, "--") == 0 ) + { + argv++; + break; + } + + if (opt) *opt++ = '\0'; /* pick off the =VALUE part */ + + if ( STRMATCH(arg, "-L") || STRMATCH(arg, "--lockfile")) + { + lockfile = getarg(opt, &argv); + } + + else if ( STRMATCH(arg, "-W") || STRMATCH(arg, "--wait")) + { + wait_for_lock = TRUE; + } + + else if ( STRMATCH(arg, "-S") || STRMATCH(arg, "--sleep")) + { + sleeptime = atoi(getarg(opt, &argv)); + } + + else if ( STRMATCH(arg, "-T") || STRMATCH(arg, "--maxtime")) + { + Maxtime = atoi(getarg(opt, &argv)); + } + + else if ( STRMATCH(arg, "-V") || STRMATCH(arg, "--verbose")) + { + Verbose++; + } + + else + { + die("ERROR: \"%s\" is an invalid cmdline param", arg); + } + } + + /*---------------------------------------------------------------- + * SANITY CHECKING + * + * Make sure that we have all the parameters we require + */ + if (*argv == 0) + die("ERROR: missing command to %s (must follow \"--\" marker) ", Argv0); + + if (lockfile == 0) + die("ERROR: missing --lockfile=F parameter"); + + /*---------------------------------------------------------------- + * Open or create the lockfile, then try to acquire the lock. If + * the lock is acquired immediately (==0), then we're done, but + * if the lock is not available, we have to wait for it. + * + * We can either loop trying for the lock (for --wait), or exit + * with error. + */ + + if ( (lfd = open(lockfile, O_RDWR|O_CREAT, openmode)) < 0) + die("ERROR: cannot open(%s) [err=%s]", lockfile, strerror(errno)); + + while ( flock(lfd, LOCK_EX | LOCK_NB) != 0 ) + { + if ( ! wait_for_lock ) + { + die("ERROR: cannot launch %s - run is locked", argv[0]); + } + + /* waiting */ + if ( Verbose ) printf("(locked: sleeping %d secs)\n", sleeptime); + + sleep(sleeptime); + } + + fflush(stdout); + + /* run the child */ + + + if ( (childpid = fork()) == 0 ) + { + close(lfd); // don't need the lock file + + execvp(argv[0], argv); + } + else if ( childpid > 0 ) + { + time_t endtime; + pid_t pid; + + if ( Verbose ) + printf("Waiting for process %ld\n", (long) childpid); + + pid = waitpid(childpid, &rc, 0); + + time(&endtime); + + endtime -= starttime; + + if ( Verbose || (Maxtime > 0 && endtime > Maxtime) ) + printf("pid %d exited with status %d (time=%ld sec)\n", pid, rc, endtime); + } + else + { + die("ERROR: cannot fork [%s]", strerror(errno)); + } + + exit(rc); +} + + +/*! \fn static char *getarg(char *opt, char ***pargv) + * \brief A function to parse calling parameters + * + * This is a helper for the main arg-processing loop: we work with + * options which are either of the form "-X=FOO" or "-X FOO"; we + * want an easy way to handle either one. + * + * The idea is that if the parameter has an = sign, we use the rest + * of that same argv[X] string, otherwise we have to get the *next* + * argv[X] string. But it's an error if an option-requiring param + * is at the end of the list with no argument to follow. + * + * The option name could be of the form "-C" or "--conf", but we + * grab it from the existing argv[] so we can report it well. + * + * \return character pointer to the argument + * + */ +static char *getarg(char *opt, char ***pargv) +{ + const char *const optname = **pargv; + + /* option already set? */ + if (opt) return opt; + + /* advance to next argv[] and try that one */ + if ((opt = *++(*pargv)) == 0) + die("ERROR: option %s requires a parameter", optname); + + return opt; +} + +/* + * die() + * + * Given a printf-style argument list, format it to the standard error, + * append a newline, then exit with error status. + */ + +static void die(const char *format, ...) +{ +va_list args; + + va_start(args, format); + vfprintf(stderr, format, args); + putc('\n', stderr); + va_end(args); + + exit(EXIT_FAILURE); +} + |