mount and umount could leak loop device allocations causing the system to

quickly run out.  Also disable init's SIGHUP handler during shutdown.
 -Erik

11 files changed, 266 insertions, 264 deletions

diff --git a/Changelog b/Changelog
index 4dbb46e..46b2a1f 100644
--- a/Changelog
+++ b/Changelog
@@ -32,6 +32,11 @@
 	    tail -f work only with a single file.  This reduced tail 
 	    from 6k to 2.4k.  The bigger/more featured tail can still be
 	    had by disabling BB_FEATURE_SIMPLE_TAIL in dusybox.defs.h
+	* Ping now falls back to doing the right thing if /etc/protocols
+	    turns up missing.
+	* Fixed mount and umount.  Previously they could leak loop device 
+	    allocations, causing the system to quickly run out.  Fix for umount
+	    by Ben Collins <bcollins@debian.org>, and mount was fixed by me.
 
 
 	-Erik Andersen
diff --git a/init.c b/init.c
index 5b80cc5..09540ff 100644
--- a/init.c
+++ b/init.c
@@ -359,6 +359,7 @@ static pid_t run(char* command,
 	signal(SIGUSR2, SIG_DFL);
 	signal(SIGINT, SIG_DFL);
 	signal(SIGTERM, SIG_DFL);
+	signal(SIGHUP, SIG_DFL);
 
 	if ((fd = device_open(terminal, O_RDWR)) < 0) {
 	    message(LOG|CONSOLE, "Bummer, can't open %s\r\n", terminal);
@@ -458,6 +459,9 @@ goodnight:
 #ifndef DEBUG_INIT
 static void shutdown_system(void)
 {
+    /* first disable our SIGHUP signal */
+    signal(SIGHUP, SIG_DFL);
+    
     /* Allow Ctrl-Alt-Del to reboot system. */
     reboot(RB_ENABLE_CAD);
     message(CONSOLE, "\r\nThe system is going down NOW !!\r\n");
diff --git a/init/init.c b/init/init.c
index 5b80cc5..09540ff 100644
--- a/init/init.c
+++ b/init/init.c
@@ -359,6 +359,7 @@ static pid_t run(char* command,
 	signal(SIGUSR2, SIG_DFL);
 	signal(SIGINT, SIG_DFL);
 	signal(SIGTERM, SIG_DFL);
+	signal(SIGHUP, SIG_DFL);
 
 	if ((fd = device_open(terminal, O_RDWR)) < 0) {
 	    message(LOG|CONSOLE, "Bummer, can't open %s\r\n", terminal);
@@ -458,6 +459,9 @@ goodnight:
 #ifndef DEBUG_INIT
 static void shutdown_system(void)
 {
+    /* first disable our SIGHUP signal */
+    signal(SIGHUP, SIG_DFL);
+    
     /* Allow Ctrl-Alt-Del to reboot system. */
     reboot(RB_ENABLE_CAD);
     message(CONSOLE, "\r\nThe system is going down NOW !!\r\n");
diff --git a/internal.h b/internal.h
index 500a63e..9611c19 100644
--- a/internal.h
+++ b/internal.h
@@ -175,6 +175,10 @@ extern int check_wildcard_match(const char* text, const char* pattern);
 extern long getNum (const char *cp);
 extern pid_t findInitPid();
 
+#if defined BB_FEATURE_MOUNT_LOOP
+extern int del_loop(const char *device);
+#endif
+
 #if defined BB_GUNZIP || defined BB_GZIP || defined BB_PRINTF || defined BB_TAIL
 extern void *xmalloc (size_t size);
 extern void error(char *msg);
diff --git a/mount.c b/mount.c
index 709c7fc..3c1568a 100644
--- a/mount.c
+++ b/mount.c
@@ -127,11 +127,11 @@ do_mount(char* specialfile, char* dir, char* filesystemtype,
 	    specialfile = find_unused_loop_device();
 	    if (specialfile == NULL) {
 		fprintf(stderr, "Could not find a spare loop device\n");
-		exit(1);
+		return( FALSE);
 	    }
 	    if (set_loop (specialfile, lofile, 0, &loro)) {
 		fprintf(stderr, "Could not setup loop device\n");
-		exit(1);
+		return( FALSE);
 	    }
 	    if (!(flags & MS_RDONLY) && loro) { /* loop is ro, but wanted rw */
 		fprintf(stderr, "WARNING: loop device is read-only\n");
@@ -141,15 +141,26 @@ do_mount(char* specialfile, char* dir, char* filesystemtype,
 #endif
 	status=mount(specialfile, dir, filesystemtype, flags, string_flags);
     }
-#if defined BB_MTAB
+
+
+    /* If the mount was sucessful, do anything needed, then return TRUE */
     if (status == 0) {
-	if (useMtab==TRUE)
+
+#if defined BB_MTAB
+	if (useMtab==TRUE) {
 	    write_mtab(specialfile, dir, filesystemtype, flags, mtab_opts);
-	return 0;
+	}
+#endif
+	return( TRUE);
+    }
+
+    /* Bummer.  mount failed.  Clean up */
+#if defined BB_FEATURE_MOUNT_LOOP
+    if (specialfile != NULL) {
+	del_loop(specialfile);
     }
-    else
 #endif
-	return(status);
+    return( FALSE);
 }
 
 
@@ -166,6 +177,75 @@ extern void whine_if_fstab_is_missing()
 #endif
 
 
+#if defined BB_FEATURE_MOUNT_LOOP
+static int set_loop(const char *device, const char *file, int offset, int *loopro)
+{
+	struct loop_info loopinfo;
+	int	fd, ffd, mode;
+	
+	mode = *loopro ? O_RDONLY : O_RDWR;
+	if ((ffd = open (file, mode)) < 0 && !*loopro
+	    && (errno != EROFS || (ffd = open (file, mode = O_RDONLY)) < 0)) {
+	  perror (file);
+	  return 1;
+	}
+	if ((fd = open (device, mode)) < 0) {
+	  close(ffd);
+	  perror (device);
+	  return 1;
+	}
+	*loopro = (mode == O_RDONLY);
+
+	memset(&loopinfo, 0, sizeof(loopinfo));
+	strncpy(loopinfo.lo_name, file, LO_NAME_SIZE);
+	loopinfo.lo_name[LO_NAME_SIZE-1] = 0;
+
+	loopinfo.lo_offset = offset;
+
+	loopinfo.lo_encrypt_key_size = 0;
+	if (ioctl(fd, LOOP_SET_FD, ffd) < 0) {
+		perror("ioctl: LOOP_SET_FD");
+		close(fd);
+		close(ffd);
+		return 1;
+	}
+	if (ioctl(fd, LOOP_SET_STATUS, &loopinfo) < 0) {
+		(void) ioctl(fd, LOOP_CLR_FD, 0);
+		perror("ioctl: LOOP_SET_STATUS");
+		close(fd);
+		close(ffd);
+		return 1;
+	}
+	close(fd);
+	close(ffd);
+	return 0;
+}
+
+char *find_unused_loop_device (void)
+{
+	char dev[20];
+	int i, fd;
+	struct stat statbuf;
+	struct loop_info loopinfo;
+
+	for(i = 0; i <= 7; i++) {
+	    sprintf(dev, "/dev/loop%d", i);
+	    if (stat (dev, &statbuf) == 0 && S_ISBLK(statbuf.st_mode)) {
+		if ((fd = open (dev, O_RDONLY)) >= 0) {
+		    if(ioctl (fd, LOOP_GET_STATUS, &loopinfo) == -1) {
+			if (errno == ENXIO) { /* probably free */
+			    close (fd);
+			    return strdup(dev);
+			}
+		    }
+		    close (fd);
+		}
+	    }
+	}
+        return NULL;
+}
+#endif /* BB_FEATURE_MOUNT_LOOP */
+
 /* Seperate standard mount options from the nonstandard string options */
 static void
 parse_mount_options ( char *options, unsigned long *flags, char *strflags)
@@ -240,7 +320,7 @@ mount_one(char *blockDevice, char *directory, char *filesystemType,
 		status = do_mount (blockDevice, directory, filesystemType,
 				flags | MS_MGC_VAL, string_flags, useMtab, 
 				fakeIt, mtab_opts);
-		if (status == 0)
+		if (status == TRUE)
 		    break;
 	    }
 	}
@@ -253,7 +333,7 @@ mount_one(char *blockDevice, char *directory, char *filesystemType,
 			fakeIt, mtab_opts);
     }
 
-    if (status) {
+    if (status==FALSE) {
 	fprintf (stderr, "Mounting %s on %s failed: %s\n",
 		 blockDevice, directory, strerror(errno));
 	return (FALSE);
@@ -400,70 +480,3 @@ goodbye:
     usage( mount_usage);
 }
 
-#if defined BB_FEATURE_MOUNT_LOOP
-static int set_loop(const char *device, const char *file, int offset, int *loopro)
-{
-	struct loop_info loopinfo;
-	int	fd, ffd, mode;
-	
-	mode = *loopro ? O_RDONLY : O_RDWR;
-	if ((ffd = open (file, mode)) < 0 && !*loopro
-	    && (errno != EROFS || (ffd = open (file, mode = O_RDONLY)) < 0)) {
-	  perror (file);
-	  return 1;
-	}
-	if ((fd = open (device, mode)) < 0) {
-	  close(ffd);
-	  perror (device);
-	  return 1;
-	}
-	*loopro = (mode == O_RDONLY);
-
-	memset(&loopinfo, 0, sizeof(loopinfo));
-	strncpy(loopinfo.lo_name, file, LO_NAME_SIZE);
-	loopinfo.lo_name[LO_NAME_SIZE-1] = 0;
-
-	loopinfo.lo_offset = offset;
-
-	loopinfo.lo_encrypt_key_size = 0;
-	if (ioctl(fd, LOOP_SET_FD, ffd) < 0) {
-		perror("ioctl: LOOP_SET_FD");
-		close(fd);
-		close(ffd);
-		return 1;
-	}
-	if (ioctl(fd, LOOP_SET_STATUS, &loopinfo) < 0) {
-		(void) ioctl(fd, LOOP_CLR_FD, 0);
-		perror("ioctl: LOOP_SET_STATUS");
-		close(fd);
-		close(ffd);
-		return 1;
-	}
-	close(fd);
-	close(ffd);
-	return 0;
-}
-
-char *find_unused_loop_device (void)
-{
-	char dev[20];
-	int i, fd;
-	struct stat statbuf;
-	struct loop_info loopinfo;
-
-	for(i = 0; i <= 7; i++) {
-		sprintf(dev, "/dev/loop%d", i);
-		if (stat (dev, &statbuf) == 0 && S_ISBLK(statbuf.st_mode)) {
-			if ((fd = open (dev, O_RDONLY)) >= 0) {
-				if(ioctl (fd, LOOP_GET_STATUS, &loopinfo) == -1 &&
-				   errno == ENXIO) { /* probably free */
-					close (fd);
-					return strdup(dev);
-				}
-				close (fd);
-			}
-		}
-	}
-        return NULL;
-}
-#endif /* BB_FEATURE_MOUNT_LOOP */
diff --git a/networking/ping.c b/networking/ping.c
index 92b62de..2b6e7f5 100644
--- a/networking/ping.c
+++ b/networking/ping.c
@@ -1,5 +1,5 @@
 /*
- * $Id: ping.c,v 1.6 1999/12/11 08:41:28 andersen Exp $
+ * $Id: ping.c,v 1.7 2000/01/26 20:06:48 erik Exp $
  * Mini ping implementation for busybox
  *
  * Copyright (C) 1999 by Randolph Chung <tausq@debian.org>
@@ -319,10 +319,11 @@ static void ping(char *host)
     int sockopt;
     
     if (!(proto = getprotobyname("icmp"))) {
-        fprintf(stderr, "ping: unknown protocol icmp\n");
-	exit(1);
+	/* getprotobyname failed, so just silently force 
+	 * proto->p_proto to have the correct value for "icmp" */
+	proto->p_proto = 1;
     }
-    if ((pingsock = socket(AF_INET, SOCK_RAW, proto->p_proto)) < 0) {
+    if ((pingsock = socket(AF_INET, SOCK_RAW, proto->p_proto)) < 0) { /* 1 == ICMP */
 	if (errno == EPERM) {
 	    fprintf(stderr, "ping: permission denied. (are you root?)\n");
 	} else {
diff --git a/ping.c b/ping.c
index 92b62de..2b6e7f5 100644
--- a/ping.c
+++ b/ping.c
@@ -1,5 +1,5 @@
 /*
- * $Id: ping.c,v 1.6 1999/12/11 08:41:28 andersen Exp $
+ * $Id: ping.c,v 1.7 2000/01/26 20:06:48 erik Exp $
  * Mini ping implementation for busybox
  *
  * Copyright (C) 1999 by Randolph Chung <tausq@debian.org>
@@ -319,10 +319,11 @@ static void ping(char *host)
     int sockopt;
     
     if (!(proto = getprotobyname("icmp"))) {
-        fprintf(stderr, "ping: unknown protocol icmp\n");
-	exit(1);
+	/* getprotobyname failed, so just silently force 
+	 * proto->p_proto to have the correct value for "icmp" */
+	proto->p_proto = 1;
     }
-    if ((pingsock = socket(AF_INET, SOCK_RAW, proto->p_proto)) < 0) {
+    if ((pingsock = socket(AF_INET, SOCK_RAW, proto->p_proto)) < 0) { /* 1 == ICMP */
 	if (errno == EPERM) {
 	    fprintf(stderr, "ping: permission denied. (are you root?)\n");
 	} else {
diff --git a/umount.c b/umount.c
index 9ad6f26..68b27e3 100644
--- a/umount.c
+++ b/umount.c
@@ -28,14 +28,6 @@
 #include <fstab.h>
 #include <errno.h>
 
-#if defined BB_FEATURE_MOUNT_LOOP
-#include <fcntl.h>
-#include <sys/ioctl.h>
-#include <linux/loop.h>
-
-static int del_loop(const char *device);
-#endif
-
 static const char umount_usage[] = 
 "umount [flags] filesystem|directory\n\n"
 "Flags:\n"
@@ -52,43 +44,34 @@ static int useMtab = TRUE;
 static int umountAll = FALSE;
 extern const char mtab_file[]; /* Defined in utility.c */
 
+#define MIN(x,y) (x > y ? x : y)
+
 static int 
 do_umount(const char* name, int useMtab)
 {
     int status;
-
-#if defined BB_FEATURE_MOUNT_LOOP
-    /* check to see if this is a loop device */
-    struct stat fst;
-    char dev[20];
-    const char *oldname = NULL;
-    int i;
-    
-    if (stat(name, &fst)) {
-	fprintf(stderr, "umount: %s: %s\n", name, strerror(errno));
-	exit(1);
-    }
-    for (i = 0 ; i <= 7 ; i++) {
-	struct stat lst;
-	sprintf(dev, "/dev/loop%d", i);
-	if (stat(dev, &lst))
-	    continue;
-	if (lst.st_dev == fst.st_dev) {
-	    oldname = name;
-	    name = dev;
-	    break;
+    struct mntent *m;
+    FILE *mountTable;
+    const char *blockDevice = NULL;
+
+    if ((mountTable = setmntent (mtab_file, "r"))) {
+	while ((m = getmntent (mountTable)) != 0) {
+	    if (strncmp(m->mnt_dir, name,
+			MIN(strlen(m->mnt_dir),strlen(name))) == 0)
+		blockDevice = m->mnt_fsname;
+	    else if (strcmp(m->mnt_fsname, name) == 0) {
+		blockDevice = name;
+		name = m->mnt_dir;
+	    }
 	}
     }
-#endif
 
     status = umount(name);
 
 #if defined BB_FEATURE_MOUNT_LOOP
-    if (!strncmp("/dev/loop", name, 9)) { /* this was a loop device, delete it */
-	del_loop(name);
-	if (oldname != NULL)
-	    name = oldname;
-    }
+    if (blockDevice != NULL && !strncmp("/dev/loop", blockDevice, 9))
+	/* this was a loop device, delete it */
+	del_loop(blockDevice);
 #endif
 #if defined BB_MTAB
     if ( status == 0 ) {
@@ -178,20 +161,3 @@ umount_main(int argc, char** argv)
     }
 }
 
-#if defined BB_FEATURE_MOUNT_LOOP
-static int del_loop(const char *device)
-{
-	int fd;
-
-	if ((fd = open(device, O_RDONLY)) < 0) {
-		perror(device);
-		exit(1);
-	}
-	if (ioctl(fd, LOOP_CLR_FD, 0) < 0) {
-		perror("ioctl: LOOP_CLR_FD");
-		exit(1);
-	}
-	close(fd);
-	return(0);
-}
-#endif
diff --git a/util-linux/mount.c b/util-linux/mount.c
index 709c7fc..3c1568a 100644
--- a/util-linux/mount.c
+++ b/util-linux/mount.c
@@ -127,11 +127,11 @@ do_mount(char* specialfile, char* dir, char* filesystemtype,
 	    specialfile = find_unused_loop_device();
 	    if (specialfile == NULL) {
 		fprintf(stderr, "Could not find a spare loop device\n");
-		exit(1);
+		return( FALSE);
 	    }
 	    if (set_loop (specialfile, lofile, 0, &loro)) {
 		fprintf(stderr, "Could not setup loop device\n");
-		exit(1);
+		return( FALSE);
 	    }
 	    if (!(flags & MS_RDONLY) && loro) { /* loop is ro, but wanted rw */
 		fprintf(stderr, "WARNING: loop device is read-only\n");
@@ -141,15 +141,26 @@ do_mount(char* specialfile, char* dir, char* filesystemtype,
 #endif
 	status=mount(specialfile, dir, filesystemtype, flags, string_flags);
     }
-#if defined BB_MTAB
+
+
+    /* If the mount was sucessful, do anything needed, then return TRUE */
     if (status == 0) {
-	if (useMtab==TRUE)
+
+#if defined BB_MTAB
+	if (useMtab==TRUE) {
 	    write_mtab(specialfile, dir, filesystemtype, flags, mtab_opts);
-	return 0;
+	}
+#endif
+	return( TRUE);
+    }
+
+    /* Bummer.  mount failed.  Clean up */
+#if defined BB_FEATURE_MOUNT_LOOP
+    if (specialfile != NULL) {
+	del_loop(specialfile);
     }
-    else
 #endif
-	return(status);
+    return( FALSE);
 }
 
 
@@ -166,6 +177,75 @@ extern void whine_if_fstab_is_missing()
 #endif
 
 
+#if defined BB_FEATURE_MOUNT_LOOP
+static int set_loop(const char *device, const char *file, int offset, int *loopro)
+{
+	struct loop_info loopinfo;
+	int	fd, ffd, mode;
+	
+	mode = *loopro ? O_RDONLY : O_RDWR;
+	if ((ffd = open (file, mode)) < 0 && !*loopro
+	    && (errno != EROFS || (ffd = open (file, mode = O_RDONLY)) < 0)) {
+	  perror (file);
+	  return 1;
+	}
+	if ((fd = open (device, mode)) < 0) {
+	  close(ffd);
+	  perror (device);
+	  return 1;
+	}
+	*loopro = (mode == O_RDONLY);
+
+	memset(&loopinfo, 0, sizeof(loopinfo));
+	strncpy(loopinfo.lo_name, file, LO_NAME_SIZE);
+	loopinfo.lo_name[LO_NAME_SIZE-1] = 0;
+
+	loopinfo.lo_offset = offset;
+
+	loopinfo.lo_encrypt_key_size = 0;
+	if (ioctl(fd, LOOP_SET_FD, ffd) < 0) {
+		perror("ioctl: LOOP_SET_FD");
+		close(fd);
+		close(ffd);
+		return 1;
+	}
+	if (ioctl(fd, LOOP_SET_STATUS, &loopinfo) < 0) {
+		(void) ioctl(fd, LOOP_CLR_FD, 0);
+		perror("ioctl: LOOP_SET_STATUS");
+		close(fd);
+		close(ffd);
+		return 1;
+	}
+	close(fd);
+	close(ffd);
+	return 0;
+}
+
+char *find_unused_loop_device (void)
+{
+	char dev[20];
+	int i, fd;
+	struct stat statbuf;
+	struct loop_info loopinfo;
+
+	for(i = 0; i <= 7; i++) {
+	    sprintf(dev, "/dev/loop%d", i);
+	    if (stat (dev, &statbuf) == 0 && S_ISBLK(statbuf.st_mode)) {
+		if ((fd = open (dev, O_RDONLY)) >= 0) {
+		    if(ioctl (fd, LOOP_GET_STATUS, &loopinfo) == -1) {
+			if (errno == ENXIO) { /* probably free */
+			    close (fd);
+			    return strdup(dev);
+			}
+		    }
+		    close (fd);
+		}
+	    }
+	}
+        return NULL;
+}
+#endif /* BB_FEATURE_MOUNT_LOOP */
+
 /* Seperate standard mount options from the nonstandard string options */
 static void
 parse_mount_options ( char *options, unsigned long *flags, char *strflags)
@@ -240,7 +320,7 @@ mount_one(char *blockDevice, char *directory, char *filesystemType,
 		status = do_mount (blockDevice, directory, filesystemType,
 				flags | MS_MGC_VAL, string_flags, useMtab, 
 				fakeIt, mtab_opts);
-		if (status == 0)
+		if (status == TRUE)
 		    break;
 	    }
 	}
@@ -253,7 +333,7 @@ mount_one(char *blockDevice, char *directory, char *filesystemType,
 			fakeIt, mtab_opts);
     }
 
-    if (status) {
+    if (status==FALSE) {
 	fprintf (stderr, "Mounting %s on %s failed: %s\n",
 		 blockDevice, directory, strerror(errno));
 	return (FALSE);
@@ -400,70 +480,3 @@ goodbye:
     usage( mount_usage);
 }
 
-#if defined BB_FEATURE_MOUNT_LOOP
-static int set_loop(const char *device, const char *file, int offset, int *loopro)
-{
-	struct loop_info loopinfo;
-	int	fd, ffd, mode;
-	
-	mode = *loopro ? O_RDONLY : O_RDWR;
-	if ((ffd = open (file, mode)) < 0 && !*loopro
-	    && (errno != EROFS || (ffd = open (file, mode = O_RDONLY)) < 0)) {
-	  perror (file);
-	  return 1;
-	}
-	if ((fd = open (device, mode)) < 0) {
-	  close(ffd);
-	  perror (device);
-	  return 1;
-	}
-	*loopro = (mode == O_RDONLY);
-
-	memset(&loopinfo, 0, sizeof(loopinfo));
-	strncpy(loopinfo.lo_name, file, LO_NAME_SIZE);
-	loopinfo.lo_name[LO_NAME_SIZE-1] = 0;
-
-	loopinfo.lo_offset = offset;
-
-	loopinfo.lo_encrypt_key_size = 0;
-	if (ioctl(fd, LOOP_SET_FD, ffd) < 0) {
-		perror("ioctl: LOOP_SET_FD");
-		close(fd);
-		close(ffd);
-		return 1;
-	}
-	if (ioctl(fd, LOOP_SET_STATUS, &loopinfo) < 0) {
-		(void) ioctl(fd, LOOP_CLR_FD, 0);
-		perror("ioctl: LOOP_SET_STATUS");
-		close(fd);
-		close(ffd);
-		return 1;
-	}
-	close(fd);
-	close(ffd);
-	return 0;
-}
-
-char *find_unused_loop_device (void)
-{
-	char dev[20];
-	int i, fd;
-	struct stat statbuf;
-	struct loop_info loopinfo;
-
-	for(i = 0; i <= 7; i++) {
-		sprintf(dev, "/dev/loop%d", i);
-		if (stat (dev, &statbuf) == 0 && S_ISBLK(statbuf.st_mode)) {
-			if ((fd = open (dev, O_RDONLY)) >= 0) {
-				if(ioctl (fd, LOOP_GET_STATUS, &loopinfo) == -1 &&
-				   errno == ENXIO) { /* probably free */
-					close (fd);
-					return strdup(dev);
-				}
-				close (fd);
-			}
-		}
-	}
-        return NULL;
-}
-#endif /* BB_FEATURE_MOUNT_LOOP */
diff --git a/util-linux/umount.c b/util-linux/umount.c
index 9ad6f26..68b27e3 100644
--- a/util-linux/umount.c
+++ b/util-linux/umount.c
@@ -28,14 +28,6 @@
 #include <fstab.h>
 #include <errno.h>
 
-#if defined BB_FEATURE_MOUNT_LOOP
-#include <fcntl.h>
-#include <sys/ioctl.h>
-#include <linux/loop.h>
-
-static int del_loop(const char *device);
-#endif
-
 static const char umount_usage[] = 
 "umount [flags] filesystem|directory\n\n"
 "Flags:\n"
@@ -52,43 +44,34 @@ static int useMtab = TRUE;
 static int umountAll = FALSE;
 extern const char mtab_file[]; /* Defined in utility.c */
 
+#define MIN(x,y) (x > y ? x : y)
+
 static int 
 do_umount(const char* name, int useMtab)
 {
     int status;
-
-#if defined BB_FEATURE_MOUNT_LOOP
-    /* check to see if this is a loop device */
-    struct stat fst;
-    char dev[20];
-    const char *oldname = NULL;
-    int i;
-    
-    if (stat(name, &fst)) {
-	fprintf(stderr, "umount: %s: %s\n", name, strerror(errno));
-	exit(1);
-    }
-    for (i = 0 ; i <= 7 ; i++) {
-	struct stat lst;
-	sprintf(dev, "/dev/loop%d", i);
-	if (stat(dev, &lst))
-	    continue;
-	if (lst.st_dev == fst.st_dev) {
-	    oldname = name;
-	    name = dev;
-	    break;
+    struct mntent *m;
+    FILE *mountTable;
+    const char *blockDevice = NULL;
+
+    if ((mountTable = setmntent (mtab_file, "r"))) {
+	while ((m = getmntent (mountTable)) != 0) {
+	    if (strncmp(m->mnt_dir, name,
+			MIN(strlen(m->mnt_dir),strlen(name))) == 0)
+		blockDevice = m->mnt_fsname;
+	    else if (strcmp(m->mnt_fsname, name) == 0) {
+		blockDevice = name;
+		name = m->mnt_dir;
+	    }
 	}
     }
-#endif
 
     status = umount(name);
 
 #if defined BB_FEATURE_MOUNT_LOOP
-    if (!strncmp("/dev/loop", name, 9)) { /* this was a loop device, delete it */
-	del_loop(name);
-	if (oldname != NULL)
-	    name = oldname;
-    }
+    if (blockDevice != NULL && !strncmp("/dev/loop", blockDevice, 9))
+	/* this was a loop device, delete it */
+	del_loop(blockDevice);
 #endif
 #if defined BB_MTAB
     if ( status == 0 ) {
@@ -178,20 +161,3 @@ umount_main(int argc, char** argv)
     }
 }
 
-#if defined BB_FEATURE_MOUNT_LOOP
-static int del_loop(const char *device)
-{
-	int fd;
-
-	if ((fd = open(device, O_RDONLY)) < 0) {
-		perror(device);
-		exit(1);
-	}
-	if (ioctl(fd, LOOP_CLR_FD, 0) < 0) {
-		perror("ioctl: LOOP_CLR_FD");
-		exit(1);
-	}
-	close(fd);
-	return(0);
-}
-#endif
diff --git a/utility.c b/utility.c
index 8139f38..643c3b5 100644
--- a/utility.c
+++ b/utility.c
@@ -36,6 +36,13 @@
 #include <unistd.h>
 #include <ctype.h>
 
+#if defined BB_FEATURE_MOUNT_LOOP
+#include <fcntl.h>
+#include <sys/ioctl.h>
+#include <linux/loop.h>
+#endif
+
+
 #if defined BB_MOUNT || defined BB_UMOUNT || defined BB_DF
 #  if defined BB_FEATURE_USE_PROCFS
 const char mtab_file[] = "/proc/mounts";
@@ -1146,4 +1153,22 @@ extern int vdprintf(int d, const char *format, va_list ap)
 }
 #endif
 
+#if defined BB_FEATURE_MOUNT_LOOP
+extern int del_loop(const char *device)
+{
+    int fd;
+
+    if ((fd = open(device, O_RDONLY)) < 0) {
+	perror(device);
+	return( FALSE);
+    }
+    if (ioctl(fd, LOOP_CLR_FD, 0) < 0) {
+	perror("ioctl: LOOP_CLR_FD");
+	return( FALSE);
+    }
+    close(fd);
+    return( TRUE);
+}
+#endif
+
 /* END CODE */