system: libdiskconfig: Add libdiskconfig

Change-Id: Ie7a7b5d8016dec60cdfb17228c3f519789c98564
Signed-off-by: San Mehat <san@google.com>

1 files changed, 325 insertions, 0 deletions

diff --git a/libdiskconfig/config_mbr.c b/libdiskconfig/config_mbr.c
new file mode 100644
index 0000000..825ba60
--- /dev/null
+++ b/libdiskconfig/config_mbr.c
@@ -0,0 +1,325 @@
+/* libs/diskconfig/diskconfig.c
+ *
+ * Copyright 2008, The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#define LOG_TAG "config_mbr"
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+
+#include <cutils/log.h>
+
+#include <diskconfig/diskconfig.h>
+
+
+/* start and len are in LBA units */
+static void
+cfg_pentry(struct pc_partition *pentry, uint8_t status, uint8_t type,
+           uint32_t start, uint32_t len)
+{
+    if (len > 0) {
+        /* seems that somes BIOSens can get wedged on boot while verifying
+         * the mbr if these are 0 */
+        memset(&pentry->start, 0xff, sizeof(struct chs));
+        memset(&pentry->end, 0xff, sizeof(struct chs));
+    } else {
+        /* zero out the c/h/s entries.. they are not used */
+        memset(&pentry->start, 0, sizeof(struct chs));
+        memset(&pentry->end, 0, sizeof(struct chs));
+    }
+
+    pentry->status = status;
+    pentry->type = type;
+    pentry->start_lba = start;
+    pentry->len_lba = len;
+
+    LOGI("Configuring pentry. status=0x%x type=0x%x start_lba=%u len_lba=%u",
+         pentry->status, pentry->type, pentry->start_lba, pentry->len_lba);
+}
+
+
+static inline uint32_t
+kb_to_lba(uint32_t len_kb, uint32_t sect_size)
+{
+    uint64_t lba;
+
+    lba = (uint64_t)len_kb * 1024;
+    /* bump it up to the next LBA boundary just in case  */
+    lba = (lba + (uint64_t)sect_size - 1) & ~((uint64_t)sect_size - 1);
+    lba /= (uint64_t)sect_size;
+    if (lba >= 0xffffffffULL)
+        LOGE("Error converting kb -> lba. 32bit overflow, expect weirdness");
+    return (uint32_t)(lba & 0xffffffffULL);
+}
+
+
+static struct write_list *
+mk_pri_pentry(struct disk_info *dinfo, struct part_info *pinfo, int pnum,
+              uint32_t *lba)
+{
+    struct write_list *item;
+    struct pc_partition *pentry;
+
+    if (pnum >= PC_NUM_BOOT_RECORD_PARTS) {
+        LOGE("Maximum number of primary partition exceeded.");
+        return NULL;
+    }
+
+    if (!(item = alloc_wl(sizeof(struct pc_partition)))) {
+        LOGE("Unable to allocate memory for partition entry.");
+        return NULL;
+    }
+
+    {
+        /* DO NOT DEREFERENCE */
+        struct pc_boot_record *mbr = (void *)PC_MBR_DISK_OFFSET; 
+        /* grab the offset in mbr where to write this partition entry. */
+        item->offset = (loff_t)((uint32_t)((uint8_t *)(&mbr->ptable[pnum])));
+    }
+
+    pentry = (struct pc_partition *) &item->data;
+
+    /* need a standard primary partition entry */
+    if (pinfo) {
+        /* need this to be 64 bit in case len_kb is large */
+        uint64_t len_lba; 
+
+        if (pinfo->len_kb != (uint32_t)-1) {
+            /* bump it up to the next LBA boundary just in case */
+            len_lba = ((uint64_t)pinfo->len_kb * 1024);
+            len_lba += ((uint64_t)dinfo->sect_size - 1);
+            len_lba &= ~((uint64_t)dinfo->sect_size - 1);
+            len_lba /= (uint64_t)dinfo->sect_size;
+        } else {
+            /* make it fill the rest of disk */
+            len_lba = dinfo->num_lba - *lba;
+        }
+
+        cfg_pentry(pentry, ((pinfo->flags & PART_ACTIVE_FLAG) ?
+                            PC_PART_ACTIVE : PC_PART_NORMAL),
+                   pinfo->type, *lba, (uint32_t)len_lba);
+
+        pinfo->start_lba = *lba;
+        *lba += (uint32_t)len_lba;
+    } else {
+        /* this should be made an extended partition, and should take
+         * up the rest of the disk as a primary partition */
+        cfg_pentry(pentry, PC_PART_NORMAL, PC_PART_TYPE_EXTENDED,
+                   *lba, dinfo->num_lba - *lba);
+
+        /* note that we do not update the *lba because we now have to
+         * create a chain of extended partition tables, and first one is at
+         * *lba */
+    }
+
+    return item;
+}
+
+
+/* This function configures an extended boot record at the beginning of an
+ * extended partition. This creates a logical partition and a pointer to
+ * the next EBR.
+ *
+ * ext_lba == The start of the toplevel extended partition (pointed to by the
+ * entry in the MBR).
+ */
+static struct write_list *
+mk_ext_pentry(struct disk_info *dinfo, struct part_info *pinfo, uint32_t *lba,
+              uint32_t ext_lba, struct part_info *pnext)
+{
+    struct write_list *item;
+    struct pc_boot_record *ebr;
+    uint32_t len; /* in lba units */
+
+    if (!(item = alloc_wl(sizeof(struct pc_boot_record)))) {
+        LOGE("Unable to allocate memory for EBR.");
+        return NULL;
+    }
+
+    /* we are going to write the ebr at the current LBA, and then bump the
+     * lba counter since that is where the logical data partition will start */
+    item->offset = (*lba) * dinfo->sect_size;
+    (*lba)++;
+
+    ebr = (struct pc_boot_record *) &item->data;
+    memset(ebr, 0, sizeof(struct pc_boot_record));
+    ebr->mbr_sig = PC_BIOS_BOOT_SIG;
+
+    if (pinfo->len_kb != (uint32_t)-1)
+        len = kb_to_lba(pinfo->len_kb, dinfo->sect_size);
+    else {
+        if (pnext) {
+            LOGE("Only the last partition can be specified to fill the disk "
+                 "(name = '%s')", pinfo->name);
+            goto fail;
+        }
+        len = dinfo->num_lba - *lba;
+        /* update the pinfo structure to reflect the new size, for
+         * bookkeeping */
+        pinfo->len_kb =
+            (uint32_t)(((uint64_t)len * (uint64_t)dinfo->sect_size) /
+                       ((uint64_t)1024));
+    }
+
+    cfg_pentry(&ebr->ptable[PC_EBR_LOGICAL_PART], PC_PART_NORMAL,
+               pinfo->type, 1, len);
+
+    pinfo->start_lba = *lba;
+    *lba += len;
+
+    /* If this is not the last partition, we have to create a link to the
+     * next extended partition.
+     *
+     * Otherwise, there's nothing to do since the "pointer entry" is
+     * already zero-filled.
+     */
+    if (pnext) {
+        /* The start lba for next partition is an offset from the beginning
+         * of the top-level extended partition */
+        uint32_t next_start_lba = *lba - ext_lba;
+        uint32_t next_len_lba;
+        if (pnext->len_kb != (uint32_t)-1)
+            next_len_lba = 1 + kb_to_lba(pnext->len_kb, dinfo->sect_size);
+        else
+            next_len_lba = dinfo->num_lba - *lba;
+        cfg_pentry(&ebr->ptable[PC_EBR_NEXT_PTR_PART], PC_PART_NORMAL,
+                   PC_PART_TYPE_EXTENDED, next_start_lba, next_len_lba);
+    }
+
+    return item;
+
+fail:
+    free_wl(item);
+    return NULL;
+}
+
+
+struct write_list *
+config_mbr(struct disk_info *dinfo)
+{
+    struct part_info *pinfo;
+    uint32_t cur_lba = dinfo->skip_lba;
+    uint32_t ext_lba = 0;
+    struct write_list *wr_list = NULL;
+    struct write_list *temp_wr = NULL;
+    int cnt = 0;
+    int extended = 0;
+
+    if (!dinfo->part_lst)
+        return NULL;
+
+    for (cnt = 0; cnt < dinfo->num_parts; ++cnt) {
+        pinfo = &dinfo->part_lst[cnt];
+
+        /* Should we create an extedned partition? */
+        if (cnt == (PC_NUM_BOOT_RECORD_PARTS - 1)) {
+            if (cnt + 1 < dinfo->num_parts) {
+                extended = 1;
+                ext_lba = cur_lba;
+                if ((temp_wr = mk_pri_pentry(dinfo, NULL, cnt, &cur_lba)))
+                    wlist_add(&wr_list, temp_wr);
+                else {
+                    LOGE("Cannot create primary extended partition.");
+                    goto fail;
+                }
+            }
+        }
+
+        /* if extended, need 1 lba for ebr */
+        if ((cur_lba + extended) >= dinfo->num_lba)
+            goto nospace;
+        else if (pinfo->len_kb != (uint32_t)-1) {
+            uint32_t sz_lba = (pinfo->len_kb / dinfo->sect_size) * 1024;
+            if ((cur_lba + sz_lba + extended) > dinfo->num_lba)
+                goto nospace;
+        }
+
+        if (!extended)
+            temp_wr = mk_pri_pentry(dinfo, pinfo, cnt, &cur_lba);
+        else {
+            struct part_info *pnext;
+            pnext = cnt + 1 < dinfo->num_parts ? &dinfo->part_lst[cnt+1] : NULL;
+            temp_wr = mk_ext_pentry(dinfo, pinfo, &cur_lba, ext_lba, pnext);
+        }
+
+        if (temp_wr)
+            wlist_add(&wr_list, temp_wr);
+        else {
+            LOGE("Cannot create partition %d (%s).", cnt, pinfo->name);
+            goto fail;
+        }
+    }
+
+    /* fill in the rest of the MBR with empty parts (if needed). */
+    for (; cnt < PC_NUM_BOOT_RECORD_PARTS; ++cnt) {
+        struct part_info blank;
+        cur_lba = 0;
+        memset(&blank, 0, sizeof(struct part_info));
+        if (!(temp_wr = mk_pri_pentry(dinfo, &blank, cnt, &cur_lba))) {
+            LOGE("Cannot create blank partition %d.", cnt);
+            goto fail;
+        }
+        wlist_add(&wr_list, temp_wr);
+    }
+
+    return wr_list;
+
+nospace:
+    LOGE("Not enough space to add parttion '%s'.", pinfo->name);
+
+fail:
+    wlist_free(wr_list);
+    return NULL;
+}
+
+
+/* Returns the device path of the partition referred to by 'name'
+ * Must be freed by the caller.
+ */
+char *
+find_mbr_part(struct disk_info *dinfo, const char *name)
+{
+    struct part_info *plist = dinfo->part_lst;
+    int num = 0;
+    char *dev_name = NULL;
+    int has_extended = (dinfo->num_parts > PC_NUM_BOOT_RECORD_PARTS);
+
+    for(num = 1; num <= dinfo->num_parts; ++num) {
+        if (!strcmp(plist[num-1].name, name))
+            break;
+    }
+
+    if (num > dinfo->num_parts)
+        return NULL;
+
+    if (has_extended && (num >= PC_NUM_BOOT_RECORD_PARTS))
+        num++;
+
+    if (!(dev_name = malloc(MAX_NAME_LEN))) {
+        LOGE("Cannot allocate memory.");
+        return NULL;
+    }
+
+    num = snprintf(dev_name, MAX_NAME_LEN, "%s%d", dinfo->device, num);
+    if (num >= MAX_NAME_LEN) {
+        LOGE("Device name is too long?!");
+        free(dev_name);
+        return NULL;
+    }
+
+    return dev_name;
+}