lsblk: ignore device if disappear while processing

If lsblk runing on system where many devices appears and disappears
during lsblk run, lsblk should not fail or crash but just ignore
disappeared device.

Let's detect context initialization failures and skip device
instead of failing.

Also fix possible dereferencing of NULL parent pointer and
properly handle some error paths.

Signed-off-by: Milan Broz <mbroz@redhat.com>
Signed-off-by: Karel Zak <kzak@redhat.com>

1 files changed, 48 insertions, 23 deletions

diff --git a/misc-utils/lsblk.c b/misc-utils/lsblk.c
index e64eb9984..2e2c457df 100644
--- a/misc-utils/lsblk.c
+++ b/misc-utils/lsblk.c
@@ -1,7 +1,7 @@
 /*
  * lsblk(8) - list block devices
  *
- * Copyright (C) 2010 Red Hat, Inc. All rights reserved.
+ * Copyright (C) 2010,2011 Red Hat, Inc. All rights reserved.
  * Written by Milan Broz <mbroz@redhat.com>
  *            Karel Zak <kzak@redhat.com>
  *
@@ -268,6 +268,9 @@ static char *get_device_mountpoint(struct blkdev_cxt *cxt)
 	int fl = 0;
 	char mnt[PATH_MAX];
 
+	assert(cxt);
+	assert(cxt->filename);
+
 	*mnt = '\0';
 
 	/*
@@ -642,14 +645,22 @@ static int set_cxt(struct blkdev_cxt *cxt,
 	cxt->partition = partition;
 
 	cxt->filename = get_device_path(cxt);
+	if (!cxt->filename) {
+		warnx(_("%s: failed to get device path"), name);
+		return -1;
+	}
 
 	devno = sysfs_devname_to_devno(name,
 			partition && parent ? parent->name : NULL);
-	if (!devno)
-		err(EXIT_FAILURE, _("%s: unknown device name"), name);
+	if (!devno) {
+		warnx(_("%s: unknown device name"), name);
+		return -1;
+	}
 
-	if (sysfs_init(&cxt->sysfs, devno, &parent->sysfs))
-		err(EXIT_FAILURE, _("%s: failed to initialize sysfs handler"), name);
+	if (sysfs_init(&cxt->sysfs, devno, parent ? &parent->sysfs : NULL)) {
+		warnx(_("%s: failed to initialize sysfs handler"), name);
+		return -1;
+	}
 
 	cxt->maj = major(devno);
 	cxt->min = minor(devno);
@@ -665,8 +676,10 @@ static int set_cxt(struct blkdev_cxt *cxt,
 
 	if (is_dm(name)) {
 		cxt->dm_name = sysfs_strdup(&cxt->sysfs, "dm/name");
-		if (!cxt->dm_name)
-			err(XALLOC_EXIT_CODE, _("cannot duplicate string"));
+		if (!cxt->dm_name) {
+			warnx(_("%s: failed to get dm name"), name);
+			return -1;
+		}
 	}
 	cxt->nholders = sysfs_count_dirents(&cxt->sysfs, "holders") +
 			sysfs_count_partitions(&cxt->sysfs, name);
@@ -702,7 +715,10 @@ static int list_holders(struct blkdev_cxt *cxt)
 		if (!sysfs_is_partition_dirent(dir, d, cxt->name))
 			continue;
 
-		set_cxt(&holder, cxt, d->d_name, 1);
+		if (set_cxt(&holder, cxt, d->d_name, 1)) {
+			reset_blkdev_cxt(&holder);
+			continue;
+		}
 		print_device(&holder, cxt->tt_line);
 		list_holders(&holder);
 		reset_blkdev_cxt(&holder);
@@ -715,7 +731,10 @@ static int list_holders(struct blkdev_cxt *cxt)
 		return 0;
 
 	while ((d = xreaddir(dir))) {
-		set_cxt(&holder, cxt, d->d_name, 0);
+		if (set_cxt(&holder, cxt, d->d_name, 0)) {
+			reset_blkdev_cxt(&holder);
+			continue;
+		}
 		print_device(&holder, cxt->tt_line);
 		list_holders(&holder);
 		reset_blkdev_cxt(&holder);
@@ -736,7 +755,6 @@ static int iterate_block_devices(void)
 		return EXIT_FAILURE;
 
 	while ((d = xreaddir(dir))) {
-
 		if (set_cxt(&cxt, NULL, d->d_name, 0))
 			goto next;
 
@@ -762,8 +780,9 @@ static int process_one_device(char *devname)
 {
 	struct blkdev_cxt parent = {}, cxt = {};
 	struct stat st;
-	char buf[PATH_MAX + 1];
+	char buf[PATH_MAX + 1], *diskname = NULL;
 	dev_t disk = 0;
+	int status = EXIT_FAILURE;
 
 	if (stat(devname, &st) || !S_ISBLK(st.st_mode)) {
 		warnx(_("%s: not a block device"), devname);
@@ -773,46 +792,52 @@ static int process_one_device(char *devname)
 		warn(_("%s: failed to get whole-list devno"), devname);
 		return EXIT_FAILURE;
 	}
-	if (st.st_rdev == disk)
+	if (st.st_rdev == disk) {
 		/*
 		 * unpartitioned device
 		 */
-		set_cxt(&cxt, NULL, buf, 0);
-	else {
+		if (set_cxt(&cxt, NULL, buf, 0))
+			goto leave;
+	} else {
 		/*
 		 * Parititioned, read sysfs name of the device
 		 */
 		ssize_t len;
-		char path[PATH_MAX], *diskname, *name;
+		char path[PATH_MAX], *name;
 
-		if (!sysfs_devno_path(st.st_rdev, path, sizeof(path)))
-			err(EXIT_FAILURE, _("failed to compose sysfs path for %s"), devname);
+		if (!sysfs_devno_path(st.st_rdev, path, sizeof(path))) {
+			warn(_("failed to compose sysfs path for %s"), devname);
+			goto leave;
+		}
 
 		diskname = xstrdup(buf);
 		len = readlink(path, buf, PATH_MAX);
 		if (len < 0) {
 			warn(_("%s: failed to read link"), path);
-			return EXIT_FAILURE;
+			goto leave;
 		}
 		buf[len] = '\0';
 
 		/* sysfs device name */
 		name = strrchr(buf, '/') + 1;
 
-		set_cxt(&parent, NULL, diskname, 0);
-		set_cxt(&cxt, &parent, name, 1);
-
-		free(diskname);
+		if (set_cxt(&parent, NULL, diskname, 0))
+			goto leave;
+		if (set_cxt(&cxt, &parent, name, 1))
+			goto leave;
 	}
 
 	print_device(&cxt, NULL);
 	list_holders(&cxt);
+	status = EXIT_SUCCESS;
+leave:
+	free(diskname);
 	reset_blkdev_cxt(&cxt);
 
 	if (st.st_rdev != disk)
 		reset_blkdev_cxt(&parent);
 
-	return EXIT_SUCCESS;
+	return status;
 }
 
 static void parse_excludes(const char *str)