1 files changed, 122 insertions, 0 deletions
diff --git a/usr.sbin/pppd/lock.c b/usr.sbin/pppd/lock.c
new file mode 100644
index 0000000..0fbbef3
--- /dev/null
+++ b/usr.sbin/pppd/lock.c
@@ -0,0 +1,122 @@
+/*
+ * lock.c - lock/unlock the serial device.
+ *
+ * This code is derived from chat.c.
+ */
+
+static char rcsid[] = "$Id: lock.c,v 1.1 1994/04/18 23:41:52 paulus Exp $";
+
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <syslog.h>
+
+#ifdef sun
+# if defined(SUNOS) && SUNOS >= 41
+# ifndef HDB
+#  define	HDB
+# endif
+# endif
+#endif
+
+#ifndef LOCK_DIR
+# ifdef __NetBSD__
+# define	PIDSTRING
+# define	LOCK_PREFIX	"/var/spool/lock/LCK.."
+# else
+#  ifdef HDB
+#   define	PIDSTRING
+#   define	LOCK_PREFIX	"/usr/spool/locks/LCK.."
+#  else /* HDB */
+#   define	LOCK_PREFIX	"/usr/spool/uucp/LCK.."
+#  endif /* HDB */
+# endif
+#endif /* LOCK_DIR */
+
+static char *lock_file;
+
+/*
+ *	Create a lock file for the named lock device
+ */
+int
+lock(dev)
+    char *dev;
+{
+    char hdb_lock_buffer[12];
+    int fd, pid, n;
+    char *p;
+
+    if ((p = strrchr(dev, '/')) != NULL)
+	dev = p + 1;
+    lock_file = malloc(strlen(LOCK_PREFIX) + strlen(dev) + 1);
+    if (lock_file == NULL)
+	novm("lock file name");
+    strcat(strcpy(lock_file, LOCK_PREFIX), dev);
+
+    while ((fd = open(lock_file, O_EXCL | O_CREAT | O_RDWR, 0644)) < 0) {
+	if (errno == EEXIST
+	    && (fd = open(lock_file, O_RDONLY, 0)) >= 0) {
+	    /* Read the lock file to find out who has the device locked */
+#ifdef PIDSTRING
+	    n = read(fd, hdb_lock_buffer, 11);
+	    if (n > 0) {
+		hdb_lock_buffer[n] = 0;
+		pid = atoi(hdb_lock_buffer);
+	    }
+#else
+	    n = read(fd, &pid, sizeof(pid));
+#endif
+	    if (n <= 0) {
+		syslog(LOG_ERR, "Can't read pid from lock file %s", lock_file);
+		close(fd);
+	    } else {
+		if (kill(pid, 0) == -1 && errno == ESRCH) {
+		    /* pid no longer exists - remove the lock file */
+		    if (unlink(lock_file) == 0) {
+			close(fd);
+			syslog(LOG_NOTICE, "Removed stale lock on %s (pid %d)",
+			       dev, pid);
+			continue;
+		    } else
+			syslog(LOG_WARNING, "Couldn't remove stale lock on %s",
+			       dev);
+		} else
+		    syslog(LOG_NOTICE, "Device %s is locked by pid %d",
+			   dev, pid);
+	    }
+	    close(fd);
+	} else
+	    syslog(LOG_ERR, "Can't create lock file %s: %m", lock_file);
+	free(lock_file);
+	lock_file = NULL;
+	return -1;
+    }
+
+# ifdef PIDSTRING
+    sprintf(hdb_lock_buffer, "%10d\n", getpid());
+    write(fd, hdb_lock_buffer, 11);
+# else
+    pid = getpid();
+    write(fd, &pid, sizeof pid);
+# endif
+
+    close(fd);
+    return 0;
+}
+
+/*
+ *	Remove our lockfile
+ */
+unlock()
+{
+    if (lock_file) {
+	unlink(lock_file);
+	free(lock_file);
+	lock_file = NULL;
+    }
+}
+