implement the -P option (writing a pid file)

src/Makefile.am

@@ -26,7 +26,11 @@ varnishevent_SOURCES = \
 	format.c \
 	handler.c \
 	vtim.h \
-	vtim.c
+	vtim.c \
+	vpf.h \
+	vpf.c \
+	flopen.h \
+	flopen.c
 
 varnishevent_LDADD = \
 	${PTHREAD_LIBS} ${RT_LIBS} ${LIBM} @VARNISH_LIBS@ \

src/flopen.c

+/*-
+ * Copyright (c) 2007 Dag-Erling Coïdan Smørgrav
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer
+ *    in this position and unchanged.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ * Derived from:
+ * $FreeBSD: head/lib/libutil/flopen.c 184094 2008-10-20 18:11:30Z des $
+ */
+
+#include "config.h"
+
+#include <sys/stat.h>
+
+#include <errno.h>
+#include <fcntl.h>
+#include <stdarg.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "flopen.h"
+
+int
+flopen(const char *path, int flags, ...)
+{
+	int fd, operation, serrno, trunc;
+	struct flock lock;
+	struct stat sb, fsb;
+	mode_t mode;
+
+#ifdef O_EXLOCK
+	flags &= ~O_EXLOCK;
+#endif
+
+	mode = 0;
+	if (flags & O_CREAT) {
+		va_list ap;
+
+		va_start(ap, flags);
+		mode = (mode_t)va_arg(ap, int); /* mode_t promoted to int */
+		va_end(ap);
+	}
+
+	memset(&lock, 0, sizeof lock);
+	lock.l_type = ((flags & O_ACCMODE) == O_RDONLY) ? F_RDLCK : F_WRLCK;
+	lock.l_whence = SEEK_SET;
+	operation = (flags & O_NONBLOCK) ? F_SETLK : F_SETLKW;
+
+	trunc = (flags & O_TRUNC);
+	flags &= ~O_TRUNC;
+
+	for (;;) {
+		if ((fd = open(path, flags, mode)) == -1)
+			/* non-existent or no access */
+			return (-1);
+		if (fcntl(fd, operation, &lock) == -1) {
+			/* unsupported or interrupted */
+			serrno = errno;
+			(void)close(fd);
+			errno = serrno;
+			return (-1);
+		}
+		if (stat(path, &sb) == -1) {
+			/* disappeared from under our feet */
+			(void)close(fd);
+			continue;
+		}
+		if (fstat(fd, &fsb) == -1) {
+			/* can't happen [tm] */
+			serrno = errno;
+			(void)close(fd);
+			errno = serrno;
+			return (-1);
+		}
+		if (sb.st_dev != fsb.st_dev ||
+		    sb.st_ino != fsb.st_ino) {
+			/* changed under our feet */
+			(void)close(fd);
+			continue;
+		}
+		if (trunc && ftruncate(fd, 0) != 0) {
+			/* can't happen [tm] */
+			serrno = errno;
+			(void)close(fd);
+			errno = serrno;
+			return (-1);
+		}
+		return (fd);
+	}
+}
+
+/* Tests if the given fd is locked through flopen
+ * If pid is non-NULL, stores the pid of the process holding the lock there
+ * Returns 1 if the file is locked
+ * Returns 0 if the file is unlocked
+ * Returns -1 on error (and errno)
+ */
+int
+fltest(int fd, pid_t *pid)
+{
+	struct flock lock;
+
+	memset(&lock, 0, sizeof lock);
+	lock.l_type = F_WRLCK;
+	lock.l_whence = SEEK_SET;
+
+	if (fcntl(fd, F_GETLK, &lock) == -1)
+		return (-1);
+	if (lock.l_type == F_UNLCK)
+		return (0);
+	if (pid != NULL)
+		*pid = lock.l_pid;
+	return (1);
+}

src/flopen.h

+/*-
+ * Copyright (c) 2007 Dag-Erling Coïdan Smørgrav
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer
+ *    in this position and unchanged.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * Derived from:
+ * $FreeBSD: src/lib/libutil/libutil.h,v 1.44 2007/05/10 15:01:42 des Exp $
+ */
+
+#ifndef FLOPEN_H_INCLUDED
+#define FLOPEN_H_INCLUDED
+
+int flopen(const char *, int, ...);
+int fltest(int fd, pid_t *pid);
+
+#endif

src/varnishevent.c

@@ -60,11 +60,7 @@
 #include <errno.h>
 
 #include "vsb.h"
-#if 0
-#include "vpf.h"
-#endif
 #include "vqueue.h"
-
 #include "vapi/vsl.h"
 #include "vre.h"
 #include "miniobj.h"
@@ -73,6 +69,7 @@
 
 #include "varnishevent.h"
 #include "vtim.h"
+#include "vpf.h"
 
 #define DEFAULT_CONFIG "/etc/varnishevent.conf"
 
@@ -416,14 +413,9 @@ int
 main(int argc, char *argv[])
 {
     int c, errnum, status, a_flag = 0, v_flag = 0, d_flag = 0, D_flag = 0;
-#if 0
-    const char *P_arg = NULL;
-#endif
-    char *w_arg = NULL, *q_arg = NULL, *g_arg = NULL;
-    char scratch[BUFSIZ];
-#if 0
+    char *P_arg = NULL, *w_arg = NULL, *q_arg = NULL, *g_arg = NULL,
+        scratch[BUFSIZ];
     struct vpf_fh *pfh = NULL;
-#endif
     struct VSL_data *vsl;
     struct VSLQ *vslq;
     struct VSM_data *vsm;
@@ -454,16 +446,14 @@ main(int argc, char *argv[])
             exit(EXIT_FAILURE);
 #endif
             break;
-#if 0
         case 'P':
-            P_arg = optarg;
+            REPLACE(P_arg, optarg);
             break;
-#endif
         case 'V':
             VCS_Message("varnishevent");
             exit(0);
         case 'w':
-            w_arg = optarg;
+            REPLACE(w_arg, optarg);
             break;
         case 'v':
             v_flag = 1;
@@ -501,21 +491,15 @@ main(int argc, char *argv[])
         }
     }
 
-#if 0
     if (P_arg && (pfh = VPF_Open(P_arg, 0644, NULL)) == NULL) {
         perror(P_arg);
-        exit(1);
+        exit(EXIT_FAILURE);
     }
-#endif
 
 #ifdef HAVE_DAEMON
     if (D_flag && daemon(0, 0) == -1) {
         perror("daemon()");
-#if 0
-        if (pfh != NULL)
-            VPF_Remove(pfh);
-#endif
-        exit(1);
+        exit(EXIT_FAILURE);
     }
 #endif
 
@@ -529,6 +513,16 @@ main(int argc, char *argv[])
 
     LOG_Log(LOG_INFO, "initializing (%s)", VCS_version);
 
+    if (pfh != NULL) {
+        errno = 0;
+        if (VPF_Write(pfh) != 0) {
+            LOG_Log(LOG_CRIT, "Cannot write pid file %s, exiting: %s", P_arg,
+                    strerror(errno));
+            exit(EXIT_FAILURE);
+        }
+        errno = 0;
+    }
+    
     /* XXX: also set grouping in config file */
     if (g_arg != NULL) {
         grouping = VSLQ_Name2Grouping(g_arg, -1);
@@ -613,11 +607,6 @@ main(int argc, char *argv[])
     /* Install signal handlers */
 #include "signals.h"
 
-#if 0
-    if (pfh != NULL)
-        VPF_Write(pfh);
-#endif
-    
     if (w_arg)
         strcpy(config.output_file, w_arg);
     if (!EMPTY(config.output_file))
@@ -769,6 +758,12 @@ main(int argc, char *argv[])
     FMT_Fini();
     AZ(pthread_cond_destroy(&spscq_ready_cond));
     AZ(pthread_mutex_destroy(&spscq_ready_lock));
+    if (pfh != NULL) {
+        errno = 0;
+        if (VPF_Remove(pfh) != 0)
+            LOG_Log(LOG_WARNING, "Could not remove pid file %s: %s", P_arg,
+                    strerror(errno));
+    }
     LOG_Log0(LOG_INFO, "Exiting");
     LOG_Close();
 

src/vpf.c

+/*-
+ * Copyright (c) 2005 Pawel Jakub Dawidek <pjd@FreeBSD.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ * Derived from:
+ * $FreeBSD: head/lib/libutil/pidfile.c 184091 2008-10-20 17:41:08Z des $
+ */
+
+#include "config.h"
+
+#include <sys/param.h>
+#include <sys/file.h>
+#include <sys/stat.h>
+
+#include <errno.h>
+#include <fcntl.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "flopen.h"
+#include "vas.h"
+#include "vpf.h"
+
+struct vpf_fh {
+	int	pf_fd;
+	char	pf_path[MAXPATHLEN + 1];
+	dev_t	pf_dev;
+	ino_t	pf_ino;
+};
+
+static int _VPF_Remove(struct vpf_fh *pfh, int freeit);
+
+static int
+vpf_verify(const struct vpf_fh *pfh)
+{
+	struct stat sb;
+
+	if (pfh == NULL || pfh->pf_fd == -1)
+		return (EINVAL);
+	/*
+	 * Check remembered descriptor.
+	 */
+	if (fstat(pfh->pf_fd, &sb) == -1)
+		return (errno);
+	if (sb.st_dev != pfh->pf_dev || sb.st_ino != pfh->pf_ino)
+		return (EINVAL);
+	return (0);
+}
+
+static int
+vpf_read(const char *path, pid_t *pidptr)
+{
+	char buf[16], *endptr;
+	int error, fd, i;
+
+	fd = open(path, O_RDONLY);
+	if (fd == -1)
+		return (errno);
+
+	i = read(fd, buf, sizeof(buf) - 1);
+	error = errno;	/* Remember errno in case close() wants to change it. */
+	(void)close(fd);
+	if (i == -1)
+		return (error);
+	buf[i] = '\0';
+
+	*pidptr = strtol(buf, &endptr, 10);
+	if (endptr != &buf[i])
+		return (EINVAL);
+
+	return (0);
+}
+
+struct vpf_fh *
+VPF_Open(const char *path, mode_t mode, pid_t *pidptr)
+{
+	struct vpf_fh *pfh;
+	struct stat sb;
+	int error, fd, len;
+
+	pfh = malloc(sizeof(*pfh));
+	if (pfh == NULL)
+		return (NULL);
+
+#if 0
+	if (path == NULL)
+		len = snprintf(pfh->pf_path, sizeof(pfh->pf_path),
+		    "/var/run/%s.pid", getprogname());
+	else
+#endif
+	{
+		assert(path != NULL);
+		len = snprintf(pfh->pf_path, sizeof(pfh->pf_path),
+		    "%s", path);
+	}
+	if (len >= (int)sizeof(pfh->pf_path)) {
+		free(pfh);
+		errno = ENAMETOOLONG;
+		return (NULL);
+	}
+
+	/*
+	 * Open the PID file and obtain exclusive lock.
+	 * We truncate PID file here only to remove old PID immediatelly,
+	 * PID file will be truncated again in VPF_Write(), so
+	 * VPF_Write() can be called multiple times.
+	 */
+	fd = flopen(pfh->pf_path,
+	    O_WRONLY | O_CREAT | O_TRUNC | O_NONBLOCK, mode);
+	if (fd == -1) {
+		if (errno == EWOULDBLOCK && pidptr != NULL) {
+			errno = vpf_read(pfh->pf_path, pidptr);
+			if (errno == 0)
+				errno = EEXIST;
+		}
+		free(pfh);
+		return (NULL);
+	}
+	/*
+	 * Remember file information, so in VPF_Write() we are sure we write
+	 * to the proper descriptor.
+	 */
+	if (fstat(fd, &sb) == -1) {
+		error = errno;
+		(void)unlink(pfh->pf_path);
+		(void)close(fd);
+		free(pfh);
+		errno = error;
+		return (NULL);
+	}
+
+	pfh->pf_fd = fd;
+	pfh->pf_dev = sb.st_dev;
+	pfh->pf_ino = sb.st_ino;
+
+	return (pfh);
+}
+
+int
+VPF_Write(struct vpf_fh *pfh)
+{
+	char pidstr[16];
+	int error, fd;
+
+	/*
+	 * Check remembered descriptor, so we don't overwrite some other
+	 * file if pidfile was closed and descriptor reused.
+	 */
+	errno = vpf_verify(pfh);
+	if (errno != 0) {
+		/*
+		 * Don't close descriptor, because we are not sure if it's ours.
+		 */
+		return (-1);
+	}
+	fd = pfh->pf_fd;
+
+	/*
+	 * Truncate PID file, so multiple calls of VPF_Write() are allowed.
+	 */
+	if (ftruncate(fd, 0) == -1) {
+		error = errno;
+		(void)_VPF_Remove(pfh, 0);
+		errno = error;
+		return (-1);
+	}
+
+	error = snprintf(pidstr, sizeof(pidstr), "%ju", (uintmax_t)getpid());
+	assert(error < sizeof pidstr);
+	if (pwrite(fd, pidstr, strlen(pidstr), 0) != (ssize_t)strlen(pidstr)) {
+		error = errno;
+		(void)_VPF_Remove(pfh, 0);
+		errno = error;
+		return (-1);
+	}
+
+	return (0);
+}
+
+int
+VPF_Close(struct vpf_fh *pfh)
+{
+	int error;
+
+	error = vpf_verify(pfh);
+	if (error != 0) {
+		errno = error;
+		return (-1);
+	}
+
+	if (close(pfh->pf_fd) == -1)
+		error = errno;
+	free(pfh);
+	if (error != 0) {
+		errno = error;
+		return (-1);
+	}
+	return (0);
+}
+
+static int
+_VPF_Remove(struct vpf_fh *pfh, int freeit)
+{
+	int error;
+
+	error = vpf_verify(pfh);
+	if (error != 0) {
+		errno = error;
+		return (-1);
+	}
+
+	if (unlink(pfh->pf_path) == -1)
+		error = errno;
+	if (close(pfh->pf_fd) == -1) {
+		if (error == 0)
+			error = errno;
+	}
+	if (freeit)
+		free(pfh);
+	else
+		pfh->pf_fd = -1;
+	if (error != 0) {
+		errno = error;
+		return (-1);
+	}
+	return (0);
+}
+
+int
+VPF_Remove(struct vpf_fh *pfh)
+{
+
+	return (_VPF_Remove(pfh, 1));
+}

src/vpf.h

+/*-
+ * Copyright (c) 2005 Pawel Jakub Dawidek <pjd@FreeBSD.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * Derived from:
+ * $FreeBSD: src/lib/libutil/libutil.h,v 1.41 2005/08/24 17:21:38 pjd Exp $
+ */
+
+#ifndef VPF_H_INCLUDED
+#define VPF_H_INCLUDED
+
+struct vpf_fh;
+
+struct vpf_fh *VPF_Open(const char *path, mode_t mode, pid_t *pidptr);
+int VPF_Write(struct vpf_fh *pfh);
+int VPF_Close(struct vpf_fh *pfh);
+int VPF_Remove(struct vpf_fh *pfh);
+
+#endif