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authorCai Zhiyong <caizhiyong@huawei.com>2013-09-11 14:20:09 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2013-09-11 15:56:57 -0700
commitbab55417b10c95e6bff8cea315c315adfa009487 (patch)
tree56bfc578d47c7ea786bf6a35bf946f37e9b458b1 /block/cmdline-parser.c
parented751e683c563be64322b9bfa0f0f7e5da9bd37c (diff)
downloadlinux-0-day-bab55417b10c95e6bff8cea315c315adfa009487.tar.gz
block: support embedded device command line partition
Read block device partition table from command line. The partition used for fixed block device (eMMC) embedded device. It is no MBR, save storage space. Bootloader can be easily accessed by absolute address of data on the block device. Users can easily change the partition. This code reference MTD partition, source "drivers/mtd/cmdlinepart.c" About the partition verbose reference "Documentation/block/cmdline-partition.txt" [akpm@linux-foundation.org: fix printk text] [yongjun_wei@trendmicro.com.cn: fix error return code in parse_parts()] Signed-off-by: Cai Zhiyong <caizhiyong@huawei.com> Cc: Karel Zak <kzak@redhat.com> Cc: "Wanglin (Albert)" <albert.wanglin@huawei.com> Cc: Marius Groeger <mag@sysgo.de> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Brian Norris <computersforpeace@gmail.com> Cc: Artem Bityutskiy <dedekind@infradead.org> Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'block/cmdline-parser.c')
-rw-r--r--block/cmdline-parser.c250
1 files changed, 250 insertions, 0 deletions
diff --git a/block/cmdline-parser.c b/block/cmdline-parser.c
new file mode 100644
index 0000000..cc2637f
--- /dev/null
+++ b/block/cmdline-parser.c
@@ -0,0 +1,250 @@
+/*
+ * Parse command line, get partition information
+ *
+ * Written by Cai Zhiyong <caizhiyong@huawei.com>
+ *
+ */
+#include <linux/buffer_head.h>
+#include <linux/module.h>
+#include <linux/cmdline-parser.h>
+
+static int parse_subpart(struct cmdline_subpart **subpart, char *partdef)
+{
+ int ret = 0;
+ struct cmdline_subpart *new_subpart;
+
+ *subpart = NULL;
+
+ new_subpart = kzalloc(sizeof(struct cmdline_subpart), GFP_KERNEL);
+ if (!new_subpart)
+ return -ENOMEM;
+
+ if (*partdef == '-') {
+ new_subpart->size = (sector_t)(~0ULL);
+ partdef++;
+ } else {
+ new_subpart->size = (sector_t)memparse(partdef, &partdef);
+ if (new_subpart->size < (sector_t)PAGE_SIZE) {
+ pr_warn("cmdline partition size is invalid.");
+ ret = -EINVAL;
+ goto fail;
+ }
+ }
+
+ if (*partdef == '@') {
+ partdef++;
+ new_subpart->from = (sector_t)memparse(partdef, &partdef);
+ } else {
+ new_subpart->from = (sector_t)(~0ULL);
+ }
+
+ if (*partdef == '(') {
+ int length;
+ char *next = strchr(++partdef, ')');
+
+ if (!next) {
+ pr_warn("cmdline partition format is invalid.");
+ ret = -EINVAL;
+ goto fail;
+ }
+
+ length = min_t(int, next - partdef,
+ sizeof(new_subpart->name) - 1);
+ strncpy(new_subpart->name, partdef, length);
+ new_subpart->name[length] = '\0';
+
+ partdef = ++next;
+ } else
+ new_subpart->name[0] = '\0';
+
+ new_subpart->flags = 0;
+
+ if (!strncmp(partdef, "ro", 2)) {
+ new_subpart->flags |= PF_RDONLY;
+ partdef += 2;
+ }
+
+ if (!strncmp(partdef, "lk", 2)) {
+ new_subpart->flags |= PF_POWERUP_LOCK;
+ partdef += 2;
+ }
+
+ *subpart = new_subpart;
+ return 0;
+fail:
+ kfree(new_subpart);
+ return ret;
+}
+
+static void free_subpart(struct cmdline_parts *parts)
+{
+ struct cmdline_subpart *subpart;
+
+ while (parts->subpart) {
+ subpart = parts->subpart;
+ parts->subpart = subpart->next_subpart;
+ kfree(subpart);
+ }
+}
+
+static int parse_parts(struct cmdline_parts **parts, const char *bdevdef)
+{
+ int ret = -EINVAL;
+ char *next;
+ int length;
+ struct cmdline_subpart **next_subpart;
+ struct cmdline_parts *newparts;
+ char buf[BDEVNAME_SIZE + 32 + 4];
+
+ *parts = NULL;
+
+ newparts = kzalloc(sizeof(struct cmdline_parts), GFP_KERNEL);
+ if (!newparts)
+ return -ENOMEM;
+
+ next = strchr(bdevdef, ':');
+ if (!next) {
+ pr_warn("cmdline partition has no block device.");
+ goto fail;
+ }
+
+ length = min_t(int, next - bdevdef, sizeof(newparts->name) - 1);
+ strncpy(newparts->name, bdevdef, length);
+ newparts->name[length] = '\0';
+ newparts->nr_subparts = 0;
+
+ next_subpart = &newparts->subpart;
+
+ while (next && *(++next)) {
+ bdevdef = next;
+ next = strchr(bdevdef, ',');
+
+ length = (!next) ? (sizeof(buf) - 1) :
+ min_t(int, next - bdevdef, sizeof(buf) - 1);
+
+ strncpy(buf, bdevdef, length);
+ buf[length] = '\0';
+
+ ret = parse_subpart(next_subpart, buf);
+ if (ret)
+ goto fail;
+
+ newparts->nr_subparts++;
+ next_subpart = &(*next_subpart)->next_subpart;
+ }
+
+ if (!newparts->subpart) {
+ pr_warn("cmdline partition has no valid partition.");
+ ret = -EINVAL;
+ goto fail;
+ }
+
+ *parts = newparts;
+
+ return 0;
+fail:
+ free_subpart(newparts);
+ kfree(newparts);
+ return ret;
+}
+
+void cmdline_parts_free(struct cmdline_parts **parts)
+{
+ struct cmdline_parts *next_parts;
+
+ while (*parts) {
+ next_parts = (*parts)->next_parts;
+ free_subpart(*parts);
+ kfree(*parts);
+ *parts = next_parts;
+ }
+}
+
+int cmdline_parts_parse(struct cmdline_parts **parts, const char *cmdline)
+{
+ int ret;
+ char *buf;
+ char *pbuf;
+ char *next;
+ struct cmdline_parts **next_parts;
+
+ *parts = NULL;
+
+ next = pbuf = buf = kstrdup(cmdline, GFP_KERNEL);
+ if (!buf)
+ return -ENOMEM;
+
+ next_parts = parts;
+
+ while (next && *pbuf) {
+ next = strchr(pbuf, ';');
+ if (next)
+ *next = '\0';
+
+ ret = parse_parts(next_parts, pbuf);
+ if (ret)
+ goto fail;
+
+ if (next)
+ pbuf = ++next;
+
+ next_parts = &(*next_parts)->next_parts;
+ }
+
+ if (!*parts) {
+ pr_warn("cmdline partition has no valid partition.");
+ ret = -EINVAL;
+ goto fail;
+ }
+
+ ret = 0;
+done:
+ kfree(buf);
+ return ret;
+
+fail:
+ cmdline_parts_free(parts);
+ goto done;
+}
+
+struct cmdline_parts *cmdline_parts_find(struct cmdline_parts *parts,
+ const char *bdev)
+{
+ while (parts && strncmp(bdev, parts->name, sizeof(parts->name)))
+ parts = parts->next_parts;
+ return parts;
+}
+
+/*
+ * add_part()
+ * 0 success.
+ * 1 can not add so many partitions.
+ */
+void cmdline_parts_set(struct cmdline_parts *parts, sector_t disk_size,
+ int slot,
+ int (*add_part)(int, struct cmdline_subpart *, void *),
+ void *param)
+
+{
+ sector_t from = 0;
+ struct cmdline_subpart *subpart;
+
+ for (subpart = parts->subpart; subpart;
+ subpart = subpart->next_subpart, slot++) {
+ if (subpart->from == (sector_t)(~0ULL))
+ subpart->from = from;
+ else
+ from = subpart->from;
+
+ if (from >= disk_size)
+ break;
+
+ if (subpart->size > (disk_size - from))
+ subpart->size = disk_size - from;
+
+ from += subpart->size;
+
+ if (add_part(slot, subpart, param))
+ break;
+ }
+}