aboutsummaryrefslogtreecommitdiffstats
path: root/contrib/fetchsetup
diff options
context:
space:
mode:
authorMatthias Andree <matthias.andree@gmx.de>2010-04-24 05:14:02 +0200
committerMatthias Andree <matthias.andree@gmx.de>2010-12-14 17:53:02 +0100
commit3718805edd205a4eb557205b0dbc476fa765d339 (patch)
tree4315e88395cb1d30056d0665901a165fe25bff21 /contrib/fetchsetup
parent771429b93137b16b0a338735488d8db15ea7ae95 (diff)
downloadfetchmail-3718805edd205a4eb557205b0dbc476fa765d339.tar.gz
fetchmail-3718805edd205a4eb557205b0dbc476fa765d339.tar.bz2
fetchmail-3718805edd205a4eb557205b0dbc476fa765d339.zip
Reduce complexity of adding UIDs in fastuidl.
Diffstat (limited to 'contrib/fetchsetup')
0 files changed, 0 insertions, 0 deletions
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-24 10:57:32 +0000
9'>129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 
/**
 * \file lock.c cross-platform concurrency locking for fetchmail
 *
 * For license terms, see the file COPYING in this directory.
 */
#include "config.h"
#include "fetchmail.h"

#include <stdio.h>
#ifdef HAVE_STRING_H
#include <string.h> /* strcat() */
#endif
#if defined(STDC_HEADERS)
#include <stdlib.h>
#endif
#if defined(HAVE_UNISTD_H)
#include <unistd.h>
#endif
#include <errno.h>
#include <fcntl.h>
#include <signal.h>

#include "i18n.h"
#include "lock.h"

static char *lockfile;		/** name of lockfile */
static int lock_acquired;	/** flag if have we acquired a lock */

void fm_lock_setup(struct runctl *ctl)
/* set up the global lockfile name */
{
    /* set up to do lock protocol */
    const char *const FETCHMAIL_PIDFILE="fetchmail.pid";

    /* command-line option override */
    if (ctl->pidfile) {
	lockfile = xstrdup(ctl->pidfile);
	return;
    }

    /* defaults */
    if (getuid() == ROOT_UID) {
	lockfile = (char *)xmalloc(strlen(PID_DIR)
		+ strlen(FETCHMAIL_PIDFILE) + 2); /* 2: "/" and NUL */
	strcpy(lockfile, PID_DIR);
	strcat(lockfile, "/");
	strcat(lockfile, FETCHMAIL_PIDFILE);
    } else {
	lockfile = (char *)xmalloc(strlen(fmhome)
		+ strlen(FETCHMAIL_PIDFILE) + 3); /* 3: "/", "." and NUL */
	strcpy(lockfile, fmhome);
	strcat(lockfile, "/");
	if (at_home)
	   strcat(lockfile, ".");
	strcat(lockfile, FETCHMAIL_PIDFILE);
    }
}

static void unlockit(void)
/* must-do actions for exit (but we can't count on being able to do malloc) */
{
    if (lockfile && lock_acquired)
	unlink(lockfile);
}

void fm_lock_dispose(void)
/* arrange for a lock to be removed on process exit */
{
#ifdef HAVE_ATEXIT
    atexit(unlockit);
#endif
}

int fm_lock_state(void)
{
    long	pid;
    int		st;
    FILE	*lockfp;
    int		bkgd = FALSE;

    if ((lockfp = fopen(lockfile, "r")) != NULL)
    {
	int args = fscanf(lockfp, "%ld %d", &pid, &st);
	bkgd = (args == 2);

	if (ferror(lockfp)) {
	    fprintf(stderr, GT_("fetchmail: error reading lockfile \"%s\": %s\n"),
		    lockfile, strerror(errno));
	    fclose(lockfp); /* not checking should be safe, file mode was "r" */
	    exit(PS_EXCLUDE);
	}
	fclose(lockfp); /* not checking should be safe, file mode was "r" */

	if (args == EOF || args == 0 || kill(pid, 0) == -1) {
	    /* ^ could not read PID  || process does not exist */
	    /* => lockfile is stale, unlink it */
	    pid = 0;
	    fprintf(stderr,GT_("fetchmail: removing stale lockfile\n"));
	    if (unlink(lockfile)) {
	       if (errno != ENOENT) {
		   perror(lockfile);
		   /* we complain but we don't exit; it might be
		    * writable for us, but in a directory we cannot
		    * write to. This means we can write the new PID to
		    * the file. Truncate to be safe in case the PID is
		    * recycled by another process later.
		    * \bug we should use fcntl() style locks or
		    * something else instead in a future release. */
		   if (truncate(lockfile, (off_t)0)) {
		       /* but if we cannot truncate the file either,
			* assume that we cannot write to it later,
			* complain and quit. */
		       perror(lockfile);
		       exit(PS_EXCLUDE);
		   }
	       }
	    }
	}
    } else {
	pid = 0;
	if (errno != ENOENT) {
	    fprintf(stderr, GT_("fetchmail: error opening lockfile \"%s\": %s\n"),
		    lockfile, strerror(errno));
	    exit(PS_EXCLUDE);
	}
    }

    return(bkgd ? -pid : pid);
}

void fm_lock_assert(void)
/* assert that we already possess a lock */
{
    lock_acquired = TRUE;
}

void fm_lock_or_die(void)
/* get a lock on a given host or exit */
{
    int fd;
    char	tmpbuf[50];

    if (!lock_acquired) {
	int e = 0;

	if ((fd = open(lockfile, O_WRONLY|O_CREAT|O_EXCL, 0666)) != -1) {
	    ssize_t wr;

	    snprintf(tmpbuf, sizeof(tmpbuf), "%ld\n", (long)getpid());
	    wr = write(fd, tmpbuf, strlen(tmpbuf));
	    if (wr == -1 || (size_t)wr != strlen(tmpbuf))
	        e = 1;
	    if (run.poll_interval)
	    {
		snprintf(tmpbuf, sizeof(tmpbuf), "%d\n", run.poll_interval);
		wr = write(fd, tmpbuf, strlen(tmpbuf));
		if (wr == -1 || (size_t)wr != strlen(tmpbuf))
		    e = 1;
	    }
	    if (fsync(fd)) e = 1;
	    if (close(fd)) e = 1;
	} else {
	    e = 1;
	}
	if (e == 0) {
	    lock_acquired = TRUE;
	} else {
	    perror(lockfile);
	    fprintf(stderr, GT_("fetchmail: lock creation failed.\n"));
	    exit(PS_EXCLUDE);
	}
    }
}

void fm_lock_release(void)
/* release a lock on a given host */
{
    unlink(lockfile);
}
/* lock.c ends here */