ubi-utils: Add ubiblock tool

With the addition of block device access to UBI volumes, we now
add a simple userspace tool to access the new ioctls.

Usage of this tool is as simple as it gets:

  $ ubiblock --create /dev/ubi0_0

will create a new block device /dev/ubiblock0_0, and

  $ ubiblock --remove /dev/ubi0_0

will remove the device.

Artem: slightly changed the header comment.

Signed-off-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>

6 files changed, 219 insertions, 1 deletions

diff --git a/Makefile b/Makefile
index 4ff8a49..d316a3d 100644
--- a/Makefile
+++ b/Makefile
@@ -28,7 +28,7 @@ MTD_BINS = \
 	sumtool jffs2reader
 UBI_BINS = \
 	ubiupdatevol ubimkvol ubirmvol ubicrc32 ubinfo ubiattach \
-	ubidetach ubinize ubiformat ubirename mtdinfo ubirsvol
+	ubidetach ubinize ubiformat ubirename mtdinfo ubirsvol ubiblock
 
 BINS = $(MTD_BINS)
 BINS += mkfs.ubifs/mkfs.ubifs
diff --git a/include/mtd/ubi-user.h b/include/mtd/ubi-user.h
index 1c06d88..2b50dad 100644
--- a/include/mtd/ubi-user.h
+++ b/include/mtd/ubi-user.h
@@ -132,6 +132,16 @@
  * used. A pointer to a &struct ubi_set_vol_prop_req object is expected to be
  * passed. The object describes which property should be set, and to which value
  * it should be set.
+ *
+ * Block devices on UBI volumes
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ *
+ * To create a R/O block device on top of an UBI volume the %UBI_IOCVOLCRBLK
+ * should be used. A pointer to a &struct ubi_blkcreate_req object is expected
+ * to be passed, which is not used and reserved for future usage.
+ *
+ * Conversely, to remove a block device the %UBI_IOCVOLRMBLK should be used,
+ * which takes no arguments.
  */
 
 /*
@@ -186,6 +196,10 @@
 /* Set an UBI volume property */
 #define UBI_IOCSETVOLPROP _IOW(UBI_VOL_IOC_MAGIC, 6, \
 			       struct ubi_set_vol_prop_req)
+/* Create a R/O block device on top of an UBI volume */
+#define UBI_IOCVOLCRBLK _IOW(UBI_VOL_IOC_MAGIC, 7, struct ubi_blkcreate_req)
+/* Remove the R/O block device */
+#define UBI_IOCVOLRMBLK _IO(UBI_VOL_IOC_MAGIC, 8)
 
 /* Maximum MTD device name length supported by UBI */
 #define MAX_UBI_MTD_NAME_LEN 127
@@ -415,4 +429,12 @@ struct ubi_set_vol_prop_req {
 	uint64_t value;
 }  __attribute__((packed));
 
+/**
+ * struct ubi_blkcreate_req - a data structure used in block creation requests.
+ * @padding: reserved for future, not used, has to be zeroed
+ */
+struct ubi_blkcreate_req {
+	int8_t  padding[128];
+}  __attribute__((packed));
+
 #endif /* __UBI_USER_H__ */
diff --git a/ubi-utils/.gitignore b/ubi-utils/.gitignore
index c035c97..19653a8 100644
--- a/ubi-utils/.gitignore
+++ b/ubi-utils/.gitignore
@@ -9,4 +9,5 @@
 /ubirmvol
 /ubiupdatevol
 /ubirsvol
+/ubiblock
 /mtdinfo
diff --git a/ubi-utils/include/libubi.h b/ubi-utils/include/libubi.h
index 47f40e2..4d6a7ee 100644
--- a/ubi-utils/include/libubi.h
+++ b/ubi-utils/include/libubi.h
@@ -400,6 +400,22 @@ int ubi_get_vol_info1_nm(libubi_t desc, int dev_num, const char *name,
 			 struct ubi_vol_info *info);
 
 /**
+ * ubi_vol_block_create - create a block device on top of an UBI volume.
+ * @fd: volume character device file descriptor
+ *
+ * Returns %0 in case of success and %-1 in case of failure.
+ */
+int ubi_vol_block_create(int fd);
+
+/**
+ * ubi_vol_block_remove - remove a block device from an UBI volume.
+ * @fd: volume character device file descriptor
+ *
+ * Returns %0 in case of success and %-1 in case of failure.
+ */
+int ubi_vol_block_remove(int fd);
+
+/**
  * ubi_update_start - start UBI volume update.
  * @desc: UBI library descriptor
  * @fd: volume character device file descriptor
diff --git a/ubi-utils/libubi.c b/ubi-utils/libubi.c
index a7463e8..598191e 100644
--- a/ubi-utils/libubi.c
+++ b/ubi-utils/libubi.c
@@ -1109,6 +1109,16 @@ int ubi_rsvol(libubi_t desc, const char *node, int vol_id, long long bytes)
 	return ret;
 }
 
+int ubi_vol_block_create(int fd)
+{
+	return ioctl(fd, UBI_IOCVOLCRBLK);
+}
+
+int ubi_vol_block_remove(int fd)
+{
+	return ioctl(fd, UBI_IOCVOLRMBLK);
+}
+
 int ubi_update_start(libubi_t desc, int fd, long long bytes)
 {
 	desc = desc;
diff --git a/ubi-utils/ubiblock.c b/ubi-utils/ubiblock.c
new file mode 100644
index 0000000..1e12be8
--- /dev/null
+++ b/ubi-utils/ubiblock.c
@@ -0,0 +1,169 @@
+/*
+ * Copyright (c) Ezequiel Garcia, 2014
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc., 51
+ * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+/*
+ * An utility to create/remove block devices on top of UBI volumes.
+ */
+
+#define PROGRAM_NAME "ubiblock"
+
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdint.h>
+#include <getopt.h>
+#include <stdarg.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/stat.h>
+
+#include <libubi.h>
+#include "common.h"
+
+struct args {
+	const char *node;
+	int create;
+};
+
+static struct args args;
+
+static const char doc[] = PROGRAM_NAME " version " VERSION
+			 " - a tool to create/remove block device interface from UBI volumes.";
+
+static const char optionsstr[] =
+"-c, --create               create block on top of a volume\n"
+"-r, --remove               remove block from volume\n"
+"-h, --help                 print help message\n"
+"-V, --version              print program version";
+
+static const char usage[] =
+"Usage: " PROGRAM_NAME " [-c,-r] <UBI volume node file name>\n"
+"Example: " PROGRAM_NAME " --create /dev/ubi0_0";
+
+static const struct option long_options[] = {
+	{ .name = "create",   .has_arg = 1, .flag = NULL, .val = 'c' },
+	{ .name = "remove",   .has_arg = 1, .flag = NULL, .val = 'r' },
+	{ .name = "help",     .has_arg = 0, .flag = NULL, .val = 'h' },
+	{ .name = "version",  .has_arg = 0, .flag = NULL, .val = 'V' },
+	{ NULL, 0, NULL, 0}
+};
+
+static int parse_opt(int argc, char * const argv[])
+{
+	while (1) {
+		int key;
+
+		key = getopt_long(argc, argv, "c:r:h?V", long_options, NULL);
+		if (key == -1)
+			break;
+
+		switch (key) {
+		case 'c':
+			args.create = 1;
+		case 'r':
+			args.node = optarg;
+			break;
+		case 'h':
+		case '?':
+			printf("%s\n\n", doc);
+			printf("%s\n\n", usage);
+			printf("%s\n", optionsstr);
+			exit(EXIT_SUCCESS);
+
+		case 'V':
+			common_print_version();
+			exit(EXIT_SUCCESS);
+
+		default:
+			fprintf(stderr, "Use -h for help\n");
+			return -1;
+		}
+	}
+
+	if (!args.node)
+		return errmsg("invalid arguments (use -h for help)");
+
+	return 0;
+}
+
+int main(int argc, char * const argv[])
+{
+	int err, fd;
+	libubi_t libubi;
+
+	err = parse_opt(argc, argv);
+	if (err)
+		return -1;
+
+	libubi = libubi_open();
+	if (!libubi) {
+		if (errno == 0)
+			errmsg("UBI is not present in the system");
+		return sys_errmsg("cannot open libubi");
+	}
+
+	err = ubi_probe_node(libubi, args.node);
+	if (err == 1) {
+		errmsg("\"%s\" is an UBI device node, not an UBI volume node",
+		       args.node);
+		goto out_libubi;
+	} else if (err < 0) {
+		if (errno == ENODEV)
+			errmsg("\"%s\" is not an UBI volume node", args.node);
+		else
+			sys_errmsg("error while probing \"%s\"", args.node);
+		goto out_libubi;
+	}
+
+	fd = open(args.node, O_RDWR);
+	if (fd == -1) {
+		sys_errmsg("cannot open UBI volume \"%s\"", args.node);
+		goto out_libubi;
+	}
+
+	if (args.create) {
+		err = ubi_vol_block_create(fd);
+		if (err) {
+			if (errno == ENOSYS)
+				errmsg("UBI block is not present in the system");
+			if (errno == ENOTTY)
+				errmsg("UBI block not supported (check your kernel version)");
+			sys_errmsg("cannot create block device");
+			goto out_close;
+		}
+	} else {
+		err = ubi_vol_block_remove(fd);
+		if (err) {
+			if (errno == ENOSYS)
+				errmsg("UBI block is not present in the system");
+			if (errno == ENOTTY)
+				errmsg("UBI block not supported (check your kernel version)");
+			sys_errmsg("cannot remove block device");
+			goto out_close;
+		}
+	}
+
+	close(fd);
+	libubi_close(libubi);
+	return 0;
+
+out_close:
+	close(fd);
+out_libubi:
+	libubi_close(libubi);
+	return -1;
+}