David Zeuthen | 227ef3c | 2015-09-03 12:23:12 -0400 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2015 The Android Open Source Project |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | |
| 17 | #include <fcntl.h> |
| 18 | #include <sys/types.h> |
| 19 | #include <sys/stat.h> |
| 20 | #include <unistd.h> |
| 21 | |
| 22 | #include <ctype.h> |
| 23 | #include <errno.h> |
| 24 | #include <stdio.h> |
| 25 | #include <stdlib.h> |
| 26 | #include <string.h> |
| 27 | |
| 28 | #include <cutils/properties.h> |
| 29 | |
| 30 | #include "fs_mgr.h" |
| 31 | #include "fs_mgr_priv.h" |
| 32 | |
| 33 | #include "bootloader.h" |
| 34 | |
| 35 | // Copies slot_suffix from misc into |out_suffix|. Returns 0 on |
| 36 | // success, -1 on error or if there is no non-empty slot_suffix. |
| 37 | static int get_active_slot_suffix_from_misc(struct fstab *fstab, |
| 38 | char *out_suffix, |
| 39 | size_t suffix_len) |
| 40 | { |
| 41 | int n; |
| 42 | int misc_fd; |
| 43 | ssize_t num_read; |
| 44 | struct bootloader_message msg; |
| 45 | |
| 46 | misc_fd = -1; |
| 47 | for (n = 0; n < fstab->num_entries; n++) { |
| 48 | if (strcmp(fstab->recs[n].mount_point, "/misc") == 0) { |
| 49 | misc_fd = open(fstab->recs[n].blk_device, O_RDONLY); |
| 50 | if (misc_fd == -1) { |
| 51 | ERROR("Error opening misc partition \"%s\" (%s)\n", |
| 52 | fstab->recs[n].blk_device, |
| 53 | strerror(errno)); |
| 54 | return -1; |
| 55 | } else { |
| 56 | break; |
| 57 | } |
| 58 | } |
| 59 | } |
| 60 | |
| 61 | if (misc_fd == -1) { |
| 62 | ERROR("Error finding misc partition\n"); |
| 63 | return -1; |
| 64 | } |
| 65 | |
| 66 | num_read = TEMP_FAILURE_RETRY(read(misc_fd, &msg, sizeof(msg))); |
| 67 | // Linux will never return partial reads when reading from block |
| 68 | // devices so no need to worry about them. |
| 69 | if (num_read != sizeof(msg)) { |
| 70 | ERROR("Error reading bootloader_message (%s)\n", strerror(errno)); |
| 71 | close(misc_fd); |
| 72 | return -1; |
| 73 | } |
| 74 | close(misc_fd); |
| 75 | if (msg.slot_suffix[0] == '\0') |
| 76 | return -1; |
| 77 | strncpy(out_suffix, msg.slot_suffix, suffix_len); |
| 78 | return 0; |
| 79 | } |
| 80 | |
David Zeuthen | bd0231c | 2015-09-09 18:15:11 -0400 | [diff] [blame] | 81 | // Gets slot_suffix from either the kernel cmdline / firmware or the |
| 82 | // misc partition. Sets |out_suffix| on success and returns 0. Returns |
| 83 | // -1 if slot_suffix could not be determined. |
| 84 | static int get_active_slot_suffix(struct fstab *fstab, char *out_suffix, |
| 85 | size_t suffix_len) |
David Zeuthen | 227ef3c | 2015-09-03 12:23:12 -0400 | [diff] [blame] | 86 | { |
| 87 | char propbuf[PROPERTY_VALUE_MAX]; |
| 88 | |
| 89 | // Get the suffix from the kernel commandline (note that we don't |
| 90 | // allow the empty suffix). On bootloaders natively supporting A/B |
| 91 | // we'll hit this path every time so don't bother logging it. |
| 92 | property_get("ro.boot.slot_suffix", propbuf, ""); |
| 93 | if (propbuf[0] != '\0') { |
| 94 | strncpy(out_suffix, propbuf, suffix_len); |
David Zeuthen | bd0231c | 2015-09-09 18:15:11 -0400 | [diff] [blame] | 95 | return 0; |
David Zeuthen | 227ef3c | 2015-09-03 12:23:12 -0400 | [diff] [blame] | 96 | } |
| 97 | |
| 98 | // If we couldn't get the suffix from the kernel cmdline, try the |
| 99 | // the misc partition. |
| 100 | if (get_active_slot_suffix_from_misc(fstab, out_suffix, suffix_len) == 0) { |
| 101 | INFO("Using slot suffix \"%s\" from misc\n", out_suffix); |
David Zeuthen | bd0231c | 2015-09-09 18:15:11 -0400 | [diff] [blame] | 102 | return 0; |
David Zeuthen | 227ef3c | 2015-09-03 12:23:12 -0400 | [diff] [blame] | 103 | } |
| 104 | |
David Zeuthen | bd0231c | 2015-09-09 18:15:11 -0400 | [diff] [blame] | 105 | ERROR("Error determining slot_suffix\n"); |
| 106 | |
| 107 | return -1; |
David Zeuthen | 227ef3c | 2015-09-03 12:23:12 -0400 | [diff] [blame] | 108 | } |
| 109 | |
| 110 | // Updates |fstab| for slot_suffix. Returns 0 on success, -1 on error. |
| 111 | int fs_mgr_update_for_slotselect(struct fstab *fstab) |
| 112 | { |
| 113 | int n; |
| 114 | char suffix[PROPERTY_VALUE_MAX]; |
| 115 | int got_suffix = 0; |
| 116 | |
| 117 | for (n = 0; n < fstab->num_entries; n++) { |
| 118 | if (fstab->recs[n].fs_mgr_flags & MF_SLOTSELECT) { |
| 119 | char *tmp; |
| 120 | |
| 121 | if (!got_suffix) { |
| 122 | memset(suffix, '\0', sizeof(suffix)); |
David Zeuthen | bd0231c | 2015-09-09 18:15:11 -0400 | [diff] [blame] | 123 | if (get_active_slot_suffix(fstab, suffix, |
| 124 | sizeof(suffix) - 1) != 0) { |
| 125 | return -1; |
| 126 | } |
David Zeuthen | 227ef3c | 2015-09-03 12:23:12 -0400 | [diff] [blame] | 127 | got_suffix = 1; |
| 128 | } |
| 129 | |
| 130 | if (asprintf(&tmp, "%s%s", fstab->recs[n].blk_device, |
| 131 | suffix) > 0) { |
| 132 | free(fstab->recs[n].blk_device); |
| 133 | fstab->recs[n].blk_device = tmp; |
| 134 | } else { |
| 135 | return -1; |
| 136 | } |
| 137 | } |
| 138 | } |
| 139 | return 0; |
| 140 | } |