[Cluster-devel] tunegfs2: Fix usage and ensure we don't try to open a null device

[Steven Whitehouse <swhiteho@redhat.com>]

This is designed to address Red Hat bz #719124 and #719126

The help message is updated to include all supported options.
Also, the return codes are now taken from sysexits.h rather
than trying to pass negative errno values as per kernel
code. There is not an exact error code for all potential
events, but they are close enough I think.

The code also checks that there is exactly one non-option
argument (i.e. the device) given before attempting to open
it.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Reported-by: Nathan Straz <nstraz@redhat.com>

diff --git a/gfs2/tune/main.c b/gfs2/tune/main.c
index 48fd59f..6a0daff 100644
--- a/gfs2/tune/main.c
+++ b/gfs2/tune/main.c
@@ -1,6 +1,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <libgen.h>
+#include <sysexits.h>
 
 #include <sys/types.h>
 #include <sys/stat.h>
@@ -51,8 +52,8 @@ void parse_mount_options(char *arg)
 
 static void usage(char *name)
 {
-	printf("Usage: %s -L <volume label> -U <UUID> -l -o "
-		"<mount options> <device> \n", basename(name));
+	printf("Usage: %s [-hlV] [-L <volume_label>] [-U <UUID>]\n\t"
+		"[-o <mount_options>] <device> \n", basename(name));
 }
 
 static void version(void)
@@ -62,14 +63,14 @@ static void version(void)
 
 int main(int argc, char **argv)
 {
-	int c, status = 0;
+	int c, status;
 
 	memset(tfs, 0, sizeof(struct tunegfs2));
 	while((c = getopt(argc, argv, "hL:U:lo:V")) != -1) {
 		switch(c) {
 		case 'h':
 			usage(argv[0]);
-			break;
+			return 0;
 		case 'L':
 			tfs->opt_label = 1;
 			tfs->label = optarg;
@@ -86,23 +87,27 @@ int main(int argc, char **argv)
 			break;
 		case 'V':
 			version();
-			break;
+			return 0;
 		default:
 			fprintf(stderr, _("Invalid option.\n"));
 			usage(argv[0]);
-			status = -EINVAL;
-			goto out;
+			return EX_USAGE;
 		}
 	}
 
+	if ((argc - optind) != 1) {
+		fprintf(stderr, _("Incorrect number of arguments\n"));
+		usage(argv[0]);
+		return EX_USAGE;
+	}
+
 	tfs->devicename = argv[optind];
 	tfs->fd = open(tfs->devicename, O_RDWR); 
 
 	if (tfs->fd < 0) {
 		fprintf(stderr, _("Unable to open device %s\n"),
 				tfs->devicename);
-		status = -EIO;
-		goto out;
+		return EX_IOERR;
 	}
 
 	status = read_super(tfs);
diff --git a/gfs2/tune/super.c b/gfs2/tune/super.c
index 056e868..9d67054 100644
--- a/gfs2/tune/super.c
+++ b/gfs2/tune/super.c
@@ -1,6 +1,6 @@
 #include <stdio.h>
 #include <stdlib.h>
-
+#include <sysexits.h>
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <errno.h>
@@ -63,7 +63,7 @@ static int str2uuid(const char *newval, char *uuid)
 
 	if (strlen(newval) != 36) {
 		fprintf(stderr, _("Invalid UUID specified.\n"));
-		return -EINVAL;
+		return EX_DATAERR;
 	}
 
 	cp = uuid;
@@ -74,13 +74,13 @@ static int str2uuid(const char *newval, char *uuid)
 				continue;
 			fprintf(stderr, _("uuid %s has an invalid format."),
 					newval);
-			return -EINVAL;
+			return EX_DATAERR;
 		}
 		if (!isxdigit(newval[i])) {
 			fprintf(stderr, _("uuid %s has an invalid hex "
 						"digit '%c' at offset %d.\n"),
 					newval, newval[i], i + 1);
-			return -EINVAL;
+			return EX_DATAERR;
 		}
 		*cp = str_to_hexchar(&newval[i++]);
 		cp++;
@@ -96,13 +96,13 @@ int read_super(struct tunegfs2 *tfs)
 	block = malloc(sizeof(char) * GFS2_DEFAULT_BSIZE);
 	n = pread(tfs->fd, block, GFS2_DEFAULT_BSIZE, tfs->sb_start);
 	if (n < 0) {
-		fprintf(stderr, _("Error reading from device"));
-		return errno;
+		perror("read_super: pread");
+		return EX_IOERR;
 	}
 	tfs->sb = block;
 	if (be32_to_cpu(tfs->sb->sb_header.mh_magic) != GFS2_MAGIC) {
 		fprintf(stderr, _("Not a GFS/GFS2 device\n"));
-		return -EINVAL;
+		return EX_IOERR;
 	}
 	return 0;
 }
@@ -144,9 +144,9 @@ int write_super(const struct tunegfs2 *tfs)
 {
 	int n;
 	n = pwrite(tfs->fd, tfs->sb, GFS2_DEFAULT_BSIZE, tfs->sb_start);
-	if (n<0) {
-		fprintf(stderr, _("Unable to write super block\n"));
-		return -errno;
+	if (n < 0) {
+		perror("write_super: pwrite");
+		return EX_IOERR;
 	}
 	return 0;
 }
@@ -164,7 +164,7 @@ int change_label(struct tunegfs2 *tfs, const char *fsname)
 	}
 	if (fsname_len < l) {
 		fprintf(stderr, _("Label too long\n"));
-		return -E2BIG;
+		return EX_DATAERR;
 	}
 	memset(sb_fsname, '\0', fsname_len);
 	memcpy(sb_fsname, fsname, l);
@@ -178,7 +178,7 @@ int change_uuid(struct tunegfs2 *tfs, const char *str)
 	if (be32_to_cpu(tfs->sb->sb_header.mh_magic) != GFS2_MAGIC) {
 		fprintf(stderr, _("UUID can be changed for a GFS2"));
 		fprintf(stderr, _(" device only\n"));
-		return -EINVAL;
+		return EX_IOERR;
 	}
 	status = str2uuid(str, uuid);
 	if (!status)
@@ -193,7 +193,7 @@ int change_lockproto(struct tunegfs2 *tfs, const char *lockproto)
 	if (strncmp(lockproto, "lock_dlm", 8) 
 			&& strncmp(lockproto, "lock_nolock", 11)) {
 		fprintf(stderr, _("Incorrect lock protocol specified\n"));
-		return -EINVAL;
+		return EX_DATAERR;
 	}
 	memset(tfs->sb->sb_lockproto, '\0', GFS2_LOCKNAME_LEN);
 	strncpy(tfs->sb->sb_lockproto, lockproto, l);
@@ -220,7 +220,7 @@ int change_locktable(struct tunegfs2 *tfs, const char *locktable)
 
 	if (l > GFS2_LOCKNAME_LEN - fsname_len - 1) {
 		fprintf(stderr, _("Lock table name too big\n"));
-		return -E2BIG;
+		return EX_DATAERR;
 	}
 	memset(t_fsname, '\0', GFS2_LOCKNAME_LEN);
 	strncpy(t_fsname, sb_fsname, fsname_len);