X-Git-Url: http://pileus.org/git/?a=blobdiff_plain;f=lock.c;h=213969f1f012f323c470ceb3a1e6b1c1aec43ffa;hb=d31db10231e9ed89f64fdf6e0fb7cae182aa377e;hp=89bf896a79d5420795bf5b80d53db972c70adcd7;hpb=6fae1ebc493bd2c9bb3c6be646f9c2de74329952;p=~andy%2Ffetchmail

diff --git a/lock.c b/lock.c
index 89bf896a..213969f1 100644
--- a/lock.c
+++ b/lock.c
@@ -1,5 +1,5 @@
-/*
- * lock.c -- cross-platform concurrency locking for fetchmail
+/**
+ * \file lock.c cross-platform concurrency locking for fetchmail
  *
  * For license terms, see the file COPYING in this directory.
  */
@@ -21,30 +21,39 @@
 
 #include "fetchmail.h"
 #include "i18n.h"
+#include "lock.h"
 
-static char *lockfile;		/* name of lockfile */
-static int lock_acquired;	/* have we acquired a lock */
+static char *lockfile;		/** name of lockfile */
+static int lock_acquired;	/** flag if have we acquired a lock */
 
-void lock_setup(void)
+void fm_lock_setup(struct runctl *ctl)
 /* set up the global lockfile name */
 {
     /* set up to do lock protocol */
-#define	FETCHMAIL_PIDFILE	"fetchmail.pid"
+    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(
-		sizeof(PID_DIR) + sizeof(FETCHMAIL_PIDFILE) + 1);
+	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)+sizeof(FETCHMAIL_PIDFILE)+2);
+	lockfile = (char *)xmalloc(strlen(fmhome)
+		+ strlen(FETCHMAIL_PIDFILE) + 3); /* 3: "/", "." and NUL */
 	strcpy(lockfile, fmhome);
 	strcat(lockfile, "/");
-        if (fmhome == home)
- 	   strcat(lockfile, ".");
+	if (fmhome == home)
+	   strcat(lockfile, ".");
 	strcat(lockfile, FETCHMAIL_PIDFILE);
     }
-#undef FETCHMAIL_PIDFILE
 }
 
 static void unlockit(void)
@@ -54,7 +63,7 @@ static void unlockit(void)
 	unlink(lockfile);
 }
 
-void lock_dispose(void)
+void fm_lock_dispose(void)
 /* arrange for a lock to be removed on process exit */
 {
 #ifdef HAVE_ATEXIT
@@ -62,45 +71,70 @@ void lock_dispose(void)
 #endif
 }
 
-int lock_state(void)
+int fm_lock_state(void)
 {
-    int		pid, st;
+    long	pid;
+    int		st;
     FILE	*lockfp;
     int		bkgd = FALSE;
 
     if ((lockfp = fopen(lockfile, "r")) != NULL)
     {
-	int args = fscanf(lockfp, "%d %d", &pid, &st);
+	int args = fscanf(lockfp, "%ld %d", &pid, &st);
 	bkgd = (args == 2);
 
-	if (ferror(lockfp))
+	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 == 0 || kill(pid, 0) == -1) {
-	    fprintf(stderr,GT_("fetchmail: removing stale lockfile\n"));
+	if (args == EOF || args == 0 || kill(pid, 0) == -1) {
+	    /* ^ could not read PID  || process does not exist */
+	    /* => lockfile is stale, unlink it */
 	    pid = 0;
-	    if (unlink(lockfile))
-		perror(lockfile);
+	    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);
+		   }
+	       }
+	    }
 	}
-	fclose(lockfp); /* not checking should be safe, file mode was "r" */
     } else {
 	pid = 0;
-	if (errno != ENOENT)
+	if (errno != ENOENT) {
 	    fprintf(stderr, GT_("fetchmail: error opening lockfile \"%s\": %s\n"),
 		    lockfile, strerror(errno));
+	    exit(PS_EXCLUDE);
+	}
     }
 
     return(bkgd ? -pid : pid);
 }
 
-void lock_assert(void)
-/* assert that we already posess a lock */
+void fm_lock_assert(void)
+/* assert that we already possess a lock */
 {
     lock_acquired = TRUE;
 }
 
-void lock_or_die(void)
+void fm_lock_or_die(void)
 /* get a lock on a given host or exit */
 {
     int fd;
@@ -110,15 +144,23 @@ void lock_or_die(void)
 	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());
-	    if (write(fd, tmpbuf, strlen(tmpbuf)) < strlen(tmpbuf)) e = 1;
+	    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);
-		if (write(fd, tmpbuf, strlen(tmpbuf)) < strlen(tmpbuf)) e = 1;
+		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;