upload android base code part6

android/system/extras/boot_control_copy/bootinfo.c

@@ -0,0 +1,181 @@
+/*
+ * Copyright (C) 2015 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.
+ */
+
+
+#include <errno.h>
+#include <fcntl.h>
+#include <linux/fs.h>
+#include <sys/ioctl.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include <arpa/inet.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <cutils/properties.h>
+
+#include <bootloader.h>
+#include <fs_mgr.h>
+
+#include "bootinfo.h"
+
+// Open the appropriate fstab file and fallback to /fstab.device if
+// that's what's being used.
+static struct fstab *open_fstab(void)
+{
+  struct fstab *fstab = fs_mgr_read_fstab_default();
+  if (fstab != NULL)
+    return fstab;
+
+  fstab = fs_mgr_read_fstab("/fstab.device");
+  return fstab;
+}
+
+int boot_info_open_partition(const char *name, uint64_t *out_size, int flags)
+{
+  char *path;
+  int fd;
+  struct fstab *fstab;
+  struct fstab_rec *record;
+
+  // We can't use fs_mgr to look up |name| because fstab doesn't list
+  // every slot partition (it uses the slotselect option to mask the
+  // suffix) and |slot| is expected to be of that form, e.g. boot_a.
+  //
+  // We can however assume that there's an entry for the /misc mount
+  // point and use that to get the device file for the misc
+  // partition. From there we'll assume that a by-name scheme is used
+  // so we can just replace the trailing "misc" by the given |name|,
+  // e.g.
+  //
+  //   /dev/block/platform/soc.0/7824900.sdhci/by-name/misc ->
+  //   /dev/block/platform/soc.0/7824900.sdhci/by-name/boot_a
+  //
+  // If needed, it's possible to relax this assumption in the future
+  // by trawling /sys/block looking for the appropriate sibling of
+  // misc and then finding an entry in /dev matching the sysfs entry.
+
+  fstab = open_fstab();
+  if (fstab == NULL)
+    return -1;
+  record = fs_mgr_get_entry_for_mount_point(fstab, "/misc");
+  if (record == NULL) {
+    fs_mgr_free_fstab(fstab);
+    return -1;
+  }
+  if (strcmp(name, "misc") == 0) {
+    path = strdup(record->blk_device);
+  } else {
+    size_t trimmed_len, name_len;
+    const char *end_slash = strrchr(record->blk_device, '/');
+    if (end_slash == NULL) {
+      fs_mgr_free_fstab(fstab);
+      return -1;
+    }
+    trimmed_len = end_slash - record->blk_device + 1;
+    name_len = strlen(name);
+    path = calloc(trimmed_len + name_len + 1, 1);
+    strncpy(path, record->blk_device, trimmed_len);
+    strncpy(path + trimmed_len, name, name_len);
+  }
+  fs_mgr_free_fstab(fstab);
+
+  fd = open(path, flags);
+  free(path);
+
+  // If we successfully opened the device, get size if requested.
+  if (fd != -1 && out_size != NULL) {
+    if (ioctl(fd, BLKGETSIZE64, out_size) != 0) {
+      close(fd);
+      return -1;
+    }
+  }
+
+  return fd;
+}
+
+// As per struct bootloader_message_ab which is defined in
+// bootable/recovery/bootloader.h we can use the 32 bytes in the
+// bootctrl_suffix field provided that they start with the active slot
+// suffix terminated by NUL. It just so happens that BrilloBootInfo is
+// laid out this way.
+#define BOOTINFO_OFFSET offsetof(struct bootloader_message_ab, slot_suffix)
+
+bool boot_info_load(BrilloBootInfo *out_info)
+{
+  int fd;
+
+  memset(out_info, '\0', sizeof(BrilloBootInfo));
+
+  fd = boot_info_open_partition("misc", NULL, O_RDONLY);
+  if (fd == -1)
+    return false;
+  if (lseek(fd, BOOTINFO_OFFSET, SEEK_SET) != BOOTINFO_OFFSET) {
+    close(fd);
+    return false;
+  }
+  ssize_t num_read;
+  do {
+    num_read = read(fd, (void*) out_info, sizeof(BrilloBootInfo));
+  } while (num_read == -1 && errno == EINTR);
+  close(fd);
+  if (num_read != sizeof(BrilloBootInfo))
+    return false;
+  return true;
+}
+
+bool boot_info_save(BrilloBootInfo *info)
+{
+  int fd;
+
+  fd = boot_info_open_partition("misc", NULL, O_RDWR);
+  if (fd == -1)
+    return false;
+  if (lseek(fd, BOOTINFO_OFFSET, SEEK_SET) != BOOTINFO_OFFSET) {
+    close(fd);
+    return false;
+  }
+  ssize_t num_written;
+  do {
+    num_written = write(fd, (void*) info, sizeof(BrilloBootInfo));
+  } while (num_written == -1 && errno == EINTR);
+  close(fd);
+  if (num_written != sizeof(BrilloBootInfo))
+    return false;
+  return true;
+}
+
+bool boot_info_validate(BrilloBootInfo* info)
+{
+  if (info->magic[0] != 'B' ||
+      info->magic[1] != 'C' ||
+      info->magic[2] != 'c')
+    return false;
+  if (info->active_slot >= 2)
+    return false;
+  return true;
+}
+
+void boot_info_reset(BrilloBootInfo* info)
+{
+  memset(info, '\0', sizeof(BrilloBootInfo));
+  info->magic[0] = 'B';
+  info->magic[1] = 'C';
+  info->magic[2] = 'c';
+}