tools: env: Add support for direct read/write UBI volumes

Up to now we were able to read/write environment data from/to UBI
volumes only indirectly by gluebi driver. This driver creates NAND MTD
on top of UBI volumes, which is quite a workaroung for this use case.

Add support for direct read/write UBI volumes in order to not use
obsolete gluebi driver.

Forward-ported from this patch:
http://patchwork.ozlabs.org/patch/619305/

Original patch:
Signed-off-by: Marcin Niestroj <m.niestroj@grinn-global.com>

Forward port:
Signed-off-by: S. Lockwood-Childs <sjl@vctlabs.com>

tools/env/fw_env.c

@@ -25,6 +25,7 @@
 #include <sys/ioctl.h>
 #include <sys/stat.h>
 #include <unistd.h>
+#include <dirent.h>
 
 #ifdef MTD_OLD
 # include <stdint.h>
@@ -34,6 +35,8 @@
 # include <mtd/mtd-user.h>
 #endif
 
+#include <mtd/ubi-user.h>
+
 #include "fw_env_private.h"
 #include "fw_env.h"
 
@@ -58,6 +61,7 @@ struct envdev_s {
 	ulong erase_size;		/* device erase size */
 	ulong env_sectors;		/* number of environment sectors */
 	uint8_t mtd_type;		/* type of the MTD device */
+	int is_ubi;			/* set if we use UBI volume */
 };
 
 static struct envdev_s envdevices[2] =
@@ -76,6 +80,7 @@ static int dev_current;
 #define DEVESIZE(i)   envdevices[(i)].erase_size
 #define ENVSECTORS(i) envdevices[(i)].env_sectors
 #define DEVTYPE(i)    envdevices[(i)].mtd_type
+#define IS_UBI(i)     envdevices[(i)].is_ubi
 
 #define CUR_ENVSIZE ENVSIZE(dev_current)
 
@@ -120,6 +125,228 @@ static unsigned char obsolete_flag = 0;
 #define DEFAULT_ENV_INSTANCE_STATIC
 #include <env_default.h>
 
+#define UBI_DEV_START "/dev/ubi"
+#define UBI_SYSFS "/sys/class/ubi"
+#define UBI_VOL_NAME_PATT "ubi%d_%d"
+
+static int is_ubi_devname(const char *devname)
+{
+	return !strncmp(devname, UBI_DEV_START, sizeof(UBI_DEV_START) - 1);
+}
+
+static int ubi_check_volume_sysfs_name(const char *volume_sysfs_name,
+				       const char *volname)
+{
+	char path[256];
+	FILE *file;
+	char *name;
+	int ret;
+
+	strcpy(path, UBI_SYSFS "/");
+	strcat(path, volume_sysfs_name);
+	strcat(path, "/name");
+
+	file = fopen(path, "r");
+	if (!file)
+		return -1;
+
+	ret = fscanf(file, "%ms", &name);
+	fclose(file);
+	if (ret <= 0 || !name) {
+		fprintf(stderr,
+			"Failed to read from file %s, ret = %d, name = %s\n",
+			path, ret, name);
+		return -1;
+	}
+
+	if (!strcmp(name, volname)) {
+		free(name);
+		return 0;
+	}
+	free(name);
+
+	return -1;
+}
+
+static int ubi_get_volnum_by_name(int devnum, const char *volname)
+{
+	DIR *sysfs_ubi;
+	struct dirent *dirent;
+	int ret;
+	int tmp_devnum;
+	int volnum;
+
+	sysfs_ubi = opendir(UBI_SYSFS);
+	if (!sysfs_ubi)
+		return -1;
+
+#ifdef DEBUG
+	fprintf(stderr, "Looking for volume name \"%s\"\n", volname);
+#endif
+
+	while (1) {
+		dirent = readdir(sysfs_ubi);
+		if (!dirent)
+			return -1;
+
+		ret = sscanf(dirent->d_name, UBI_VOL_NAME_PATT,
+			     &tmp_devnum, &volnum);
+		if (ret == 2 && devnum == tmp_devnum) {
+			if (ubi_check_volume_sysfs_name(dirent->d_name,
+							volname) == 0)
+				return volnum;
+		}
+	}
+
+	return -1;
+}
+
+static int ubi_get_devnum_by_devname(const char *devname)
+{
+	int devnum;
+	int ret;
+
+	ret = sscanf(devname + sizeof(UBI_DEV_START) - 1, "%d", &devnum);
+	if (ret != 1)
+		return -1;
+
+	return devnum;
+}
+
+static const char *ubi_get_volume_devname(const char *devname,
+					  const char *volname)
+{
+	char *volume_devname;
+	int volnum;
+	int devnum;
+	int ret;
+
+	devnum = ubi_get_devnum_by_devname(devname);
+	if (devnum < 0)
+		return NULL;
+
+	volnum = ubi_get_volnum_by_name(devnum, volname);
+	if (volnum < 0)
+		return NULL;
+
+	ret = asprintf(&volume_devname, "%s_%d", devname, volnum);
+	if (ret < 0)
+		return NULL;
+
+#ifdef DEBUG
+	fprintf(stderr, "Found ubi volume \"%s:%s\" -> %s\n",
+		devname, volname, volume_devname);
+#endif
+
+	return volume_devname;
+}
+
+static void ubi_check_dev(unsigned int dev_id)
+{
+	char *devname = (char *)DEVNAME(dev_id);
+	char *pname;
+	const char *volname = NULL;
+	const char *volume_devname;
+
+	if (!is_ubi_devname(DEVNAME(dev_id)))
+		return;
+
+	IS_UBI(dev_id) = 1;
+
+	for (pname = devname; *pname != '\0'; pname++) {
+		if (*pname == ':') {
+			*pname = '\0';
+			volname = pname + 1;
+			break;
+		}
+	}
+
+	if (volname) {
+		/* Let's find real volume device name */
+		volume_devname = ubi_get_volume_devname(devname, volname);
+		if (!volume_devname) {
+			fprintf(stderr, "Didn't found ubi volume \"%s\"\n",
+				volname);
+			return;
+		}
+
+		free(devname);
+		DEVNAME(dev_id) = volume_devname;
+	}
+}
+
+static int ubi_update_start(int fd, int64_t bytes)
+{
+	if (ioctl(fd, UBI_IOCVOLUP, &bytes))
+		return -1;
+	return 0;
+}
+
+static int ubi_read(int fd, void *buf, size_t count)
+{
+	ssize_t ret;
+
+	while (count > 0) {
+		ret = read(fd, buf, count);
+		if (ret > 0) {
+			count -= ret;
+			buf += ret;
+
+			continue;
+		}
+
+		if (ret == 0) {
+			/*
+			 * Happens in case of too short volume data size. If we
+			 * return error status we will fail it will be treated
+			 * as UBI device error.
+			 *
+			 * Leave catching this error to CRC check.
+			 */
+			fprintf(stderr, "Warning: end of data on ubi volume\n");
+			return 0;
+		} else if (errno == EBADF) {
+			/*
+			 * Happens in case of corrupted volume. The same as
+			 * above, we cannot return error now, as we will still
+			 * be able to successfully write environment later.
+			 */
+			fprintf(stderr, "Warning: corrupted volume?\n");
+			return 0;
+		} else if (errno == EINTR) {
+			continue;
+		}
+
+		fprintf(stderr, "Cannot read %u bytes from ubi volume, %s\n",
+			(unsigned int)count, strerror(errno));
+		return -1;
+	}
+
+	return 0;
+}
+
+static int ubi_write(int fd, const void *buf, size_t count)
+{
+	ssize_t ret;
+
+	while (count > 0) {
+		ret = write(fd, buf, count);
+		if (ret <= 0) {
+			if (ret < 0 && errno == EINTR)
+				continue;
+
+			fprintf(stderr, "Cannot write %u bytes to ubi volume\n",
+				(unsigned int)count);
+			return -1;
+		}
+
+		count -= ret;
+		buf += ret;
+	}
+
+	return 0;
+}
+
 static int flash_io (int mode);
 static int parse_config(struct env_opts *opts);
 
@@ -960,6 +1187,12 @@ static int flash_write (int fd_current, int fd_target, int dev_target)
 		DEVOFFSET (dev_target), DEVNAME (dev_target));
 #endif
 
+	if (IS_UBI(dev_target)) {
+		if (ubi_update_start(fd_target, CUR_ENVSIZE) < 0)
+			return 0;
+		return ubi_write(fd_target, environment.image, CUR_ENVSIZE);
+	}
+
 	rc = flash_write_buf(dev_target, fd_target, environment.image,
 			     CUR_ENVSIZE);
 	if (rc < 0)
@@ -984,6 +1217,12 @@ static int flash_read (int fd)
 {
 	int rc;
 
+	if (IS_UBI(dev_current)) {
+		DEVTYPE(dev_current) = MTD_ABSENT;
+
+		return ubi_read(fd, environment.image, CUR_ENVSIZE);
+	}
+
 	rc = flash_read_buf(dev_current, fd, environment.image, CUR_ENVSIZE,
 			    DEVOFFSET(dev_current));
 	if (rc != CUR_ENVSIZE)
@@ -1165,7 +1404,8 @@ int fw_env_open(struct env_opts *opts)
 			   DEVTYPE(!dev_current) == MTD_UBIVOLUME) {
 			environment.flag_scheme = FLAG_INCREMENTAL;
 		} else if (DEVTYPE(dev_current) == MTD_ABSENT &&
-			   DEVTYPE(!dev_current) == MTD_ABSENT) {
+			   DEVTYPE(!dev_current) == MTD_ABSENT &&
+			   IS_UBI(dev_current) == IS_UBI(!dev_current)) {
 			environment.flag_scheme = FLAG_INCREMENTAL;
 		} else {
 			fprintf (stderr, "Incompatible flash types!\n");
@@ -1271,8 +1511,12 @@ int fw_env_close(struct env_opts *opts)
 static int check_device_config(int dev)
 {
 	struct stat st;
+	int32_t lnum = 0;
 	int fd, rc = 0;
 
+	/* Fills in IS_UBI(), converts DEVNAME() with ubi volume name */
+	ubi_check_dev(dev);
+
 	fd = open(DEVNAME(dev), O_RDONLY);
 	if (fd < 0) {
 		fprintf(stderr,
@@ -1288,7 +1532,14 @@ static int check_device_config(int dev)
 		goto err;
 	}
 
-	if (S_ISCHR(st.st_mode)) {
+	if (IS_UBI(dev)) {
+		rc = ioctl(fd, UBI_IOCEBISMAP, &lnum);
+		if (rc < 0) {
+			fprintf(stderr, "Cannot get UBI information for %s\n",
+				DEVNAME(dev));
+			goto err;
+		}
+	} else if (S_ISCHR(st.st_mode)) {
 		struct mtd_info_user mtdinfo;
 		rc = ioctl(fd, MEMGETINFO, &mtdinfo);
 		if (rc < 0) {

tools/env/fw_env.config

@@ -28,3 +28,11 @@
 
 # VFAT example
 #/boot/uboot.env	0x0000          0x4000
+
+# UBI volume
+#/dev/ubi0_0		0x0		0x1f000		0x1f000
+#/dev/ubi0_1		0x0		0x1f000		0x1f000
+
+# UBI volume by name
+#/dev/ubi0:env		0x0		0x1f000		0x1f000
+#/dev/ubi0:env-redund	0x0		0x1f000		0x1f000