122 lines
2.8 KiB
C
122 lines
2.8 KiB
C
/* source: xiolockfile.c */
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/* Copyright Gerhard Rieger 2005-2011 */
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/* Published under the GNU General Public License V.2, see file COPYING */
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/* this file contains socats explicit locking mechanisms */
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#include "xiosysincludes.h"
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#include "compat.h"
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#include "mytypes.h"
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#include "error.h"
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#include "utils.h"
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#include "sysutils.h"
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#include "sycls.h"
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#include "xio.h"
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#include "xiolockfile.h"
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/* returns 0 if it could create lock; 1 if the lock exists; -1 on error */
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int xiogetlock(const char *lockfile) {
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char *s;
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struct stat strat;
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int fd;
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pid_t pid;
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char pidbuf[3*sizeof(pid_t)+1];
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size_t bytes;
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if (Lstat(lockfile, &strat) == 0) {
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return 1;
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}
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switch (errno) {
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case ENOENT: break;
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default:
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Error3("Lstat(\"%s\", %p): %s", lockfile, &strat, strerror(errno));
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return -1;
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}
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/* in this moment, the file did not exist */
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if ((s = Malloc(strlen(lockfile)+8)) == NULL) {
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errno = ENOMEM;
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return -1;
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}
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strcpy(s, lockfile);
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strcat(s, ".XXXXXX");
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if ((fd = Mkstemp(s)) < 0) {
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Error2("mkstemp(\"%s\"): %s", s, strerror(errno));
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return -1;
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}
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pid = Getpid();
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bytes = sprintf(pidbuf, F_pid, pid);
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if (writefull(fd, pidbuf, bytes) < 0) {
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Error4("write(%d, %p, "F_Zu"): %s", fd, pidbuf, bytes, strerror(errno));
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return -1;
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}
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Close(fd);
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/* Chmod(lockfile, 0600); */
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if (Link(s, lockfile) < 0) {
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int _errno = errno;
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Error3("link(\"%s\", \"%s\"): %s", s, lockfile, strerror(errno));
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Unlink(s);
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errno = _errno;
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return -1;
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}
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Unlink(s);
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return 0;
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}
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int xiounlock(const char *lockfile) {
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return Unlink(lockfile);
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}
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/* returns 0 when it could create lock, or -1 on error */
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int xiowaitlock(const char *lockfile, struct timespec *intervall) {
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int rc;
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int level = E_NOTICE; /* first print a notice */
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while ((rc = xiogetlock(lockfile)) == 1) {
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Msg1(level, "waiting for lock \"%s\"", lockfile);
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level = E_INFO; /* afterwards only make info */
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Nanosleep(intervall, NULL);
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}
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return rc;
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}
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/* returns 0 when it could obtain lock or the lock is not valid
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(lockfile==NULL), 1 if it could not obtain the lock, or -1 on error */
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int xiolock(xiolock_t *lock) {
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int result;
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if (lock->lockfile == NULL) {
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return 0;
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}
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if (lock->waitlock) {
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result = xiowaitlock(lock->lockfile, &lock->intervall);
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} else {
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result = xiogetlock(lock->lockfile);
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}
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if (result == 0) {
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Info1("obtained lock \"%s\"", lock->lockfile);
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}
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return result;
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}
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int xiofiledroplock(xiofile_t *xfd) {
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if (xfd->tag == XIO_TAG_DUAL) {
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xiofiledroplock((xiofile_t *)xfd->dual.stream[0]);
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xiofiledroplock((xiofile_t *)xfd->dual.stream[1]);
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} else {
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xfd->stream.havelock = false;
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}
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return 0;
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}
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