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-rw-r--r--block/partitions/cmdline.c411
1 files changed, 411 insertions, 0 deletions
diff --git a/block/partitions/cmdline.c b/block/partitions/cmdline.c
new file mode 100644
index 000000000..1af610f0b
--- /dev/null
+++ b/block/partitions/cmdline.c
@@ -0,0 +1,411 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2013 HUAWEI
+ * Author: Cai Zhiyong <caizhiyong@huawei.com>
+ *
+ * Read block device partition table from the command line.
+ * Typically used for fixed block (eMMC) embedded devices.
+ * It has no MBR, so saves storage space. Bootloader can be easily accessed
+ * by absolute address of data on the block device.
+ * Users can easily change the partition.
+ *
+ * The format for the command line is just like mtdparts.
+ *
+ * For further information, see "Documentation/block/cmdline-partition.rst"
+ *
+ */
+#include <linux/blkdev.h>
+#include <linux/fs.h>
+#include <linux/slab.h>
+#include "check.h"
+
+
+/* partition flags */
+#define PF_RDONLY 0x01 /* Device is read only */
+#define PF_POWERUP_LOCK 0x02 /* Always locked after reset */
+
+struct cmdline_subpart {
+ char name[BDEVNAME_SIZE]; /* partition name, such as 'rootfs' */
+ sector_t from;
+ sector_t size;
+ int flags;
+ struct cmdline_subpart *next_subpart;
+};
+
+struct cmdline_parts {
+ char name[BDEVNAME_SIZE]; /* block device, such as 'mmcblk0' */
+ unsigned int nr_subparts;
+ struct cmdline_subpart *subpart;
+ struct cmdline_parts *next_parts;
+};
+
+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;
+}
+
+static 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;
+ }
+}
+
+static 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;
+}
+
+static 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;
+}
+
+static char *cmdline;
+static struct cmdline_parts *bdev_parts;
+
+static int add_part(int slot, struct cmdline_subpart *subpart,
+ struct parsed_partitions *state)
+{
+ int label_min;
+ struct partition_meta_info *info;
+ char tmp[sizeof(info->volname) + 4];
+
+ if (slot >= state->limit)
+ return 1;
+
+ put_partition(state, slot, subpart->from >> 9,
+ subpart->size >> 9);
+
+ info = &state->parts[slot].info;
+
+ label_min = min_t(int, sizeof(info->volname) - 1,
+ sizeof(subpart->name));
+ strncpy(info->volname, subpart->name, label_min);
+ info->volname[label_min] = '\0';
+
+ snprintf(tmp, sizeof(tmp), "(%s)", info->volname);
+ strlcat(state->pp_buf, tmp, PAGE_SIZE);
+
+ state->parts[slot].has_info = true;
+
+ return 0;
+}
+
+static int cmdline_parts_set(struct cmdline_parts *parts, sector_t disk_size,
+ struct parsed_partitions *state)
+{
+ sector_t from = 0;
+ struct cmdline_subpart *subpart;
+ int slot = 1;
+
+ 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, state))
+ break;
+ }
+
+ return slot;
+}
+
+static int __init cmdline_parts_setup(char *s)
+{
+ cmdline = s;
+ return 1;
+}
+__setup("blkdevparts=", cmdline_parts_setup);
+
+static bool has_overlaps(sector_t from, sector_t size,
+ sector_t from2, sector_t size2)
+{
+ sector_t end = from + size;
+ sector_t end2 = from2 + size2;
+
+ if (from >= from2 && from < end2)
+ return true;
+
+ if (end > from2 && end <= end2)
+ return true;
+
+ if (from2 >= from && from2 < end)
+ return true;
+
+ if (end2 > from && end2 <= end)
+ return true;
+
+ return false;
+}
+
+static inline void overlaps_warns_header(void)
+{
+ pr_warn("Overlapping partitions are used in command line partitions.");
+ pr_warn("Don't use filesystems on overlapping partitions:");
+}
+
+static void cmdline_parts_verifier(int slot, struct parsed_partitions *state)
+{
+ int i;
+ bool header = true;
+
+ for (; slot < state->limit && state->parts[slot].has_info; slot++) {
+ for (i = slot+1; i < state->limit && state->parts[i].has_info;
+ i++) {
+ if (has_overlaps(state->parts[slot].from,
+ state->parts[slot].size,
+ state->parts[i].from,
+ state->parts[i].size)) {
+ if (header) {
+ header = false;
+ overlaps_warns_header();
+ }
+ pr_warn("%s[%llu,%llu] overlaps with "
+ "%s[%llu,%llu].",
+ state->parts[slot].info.volname,
+ (u64)state->parts[slot].from << 9,
+ (u64)state->parts[slot].size << 9,
+ state->parts[i].info.volname,
+ (u64)state->parts[i].from << 9,
+ (u64)state->parts[i].size << 9);
+ }
+ }
+ }
+}
+
+/*
+ * Purpose: allocate cmdline partitions.
+ * Returns:
+ * -1 if unable to read the partition table
+ * 0 if this isn't our partition table
+ * 1 if successful
+ */
+int cmdline_partition(struct parsed_partitions *state)
+{
+ sector_t disk_size;
+ struct cmdline_parts *parts;
+
+ if (cmdline) {
+ if (bdev_parts)
+ cmdline_parts_free(&bdev_parts);
+
+ if (cmdline_parts_parse(&bdev_parts, cmdline)) {
+ cmdline = NULL;
+ return -1;
+ }
+ cmdline = NULL;
+ }
+
+ if (!bdev_parts)
+ return 0;
+
+ parts = cmdline_parts_find(bdev_parts, state->disk->disk_name);
+ if (!parts)
+ return 0;
+
+ disk_size = get_capacity(state->disk) << 9;
+
+ cmdline_parts_set(parts, disk_size, state);
+ cmdline_parts_verifier(1, state);
+
+ strlcat(state->pp_buf, "\n", PAGE_SIZE);
+
+ return 1;
+}
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