| /* |
| * Copyright (C) 2010 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. |
| */ |
| |
| /* Limited driver for the Qcow2 filesystem, capable of extracting snapshot |
| * metadata from Qcow2 formatted image file. |
| * |
| * Similar functionality is implemented in block/qcow2.c, block/qcow2-snapshot.c |
| * and block.c. This separate implementation was made to further decouple the UI |
| * of the Android emulator from the underlying Qemu system. It allows the UI to |
| * show snapshot listings without having to fall back on Qemu's block driver |
| * system, which would pull in a lot of code irrelevant for the UI. |
| */ |
| |
| #include <errno.h> |
| #include <fcntl.h> |
| #include <stdint.h> |
| #include <stdio.h> |
| #include <stdlib.h> |
| #include <string.h> |
| #include <time.h> |
| #include <unistd.h> |
| |
| #include "android/utils/debug.h" |
| #include "android/utils/system.h" |
| #include "bswap.h" |
| #include "snapshot.h" |
| |
| #if CONFIG_ANDROID_SNAPSHOTS |
| |
| /* "Magic" sequence of four bytes required by spec to be the first four bytes |
| * of any Qcow file. |
| */ |
| #define QCOW_MAGIC (('Q' << 24) | ('F' << 16) | ('I' << 8) | 0xfb) |
| #define QCOW_VERSION 2 |
| |
| /* Reads 'nbyte' bytes from 'fd' into 'buf', retrying on interrupts. |
| * Exit()s if the read fails for any other reason. |
| */ |
| static int |
| read_or_die(int fd, void *buf, size_t nbyte) |
| { |
| int ret = 0; |
| do { |
| ret = read(fd, buf, nbyte); |
| } |
| while(ret < 0 && errno == EINTR); |
| |
| if (ret < 0) { |
| derror("read failed: %s", strerror(errno)); |
| exit(1); |
| } |
| |
| return ret; |
| } |
| |
| /* Wrapper around lseek(), exit()s on error. |
| */ |
| static off_t |
| seek_or_die(int fd, off_t offset, int whence) |
| { |
| off_t ret = lseek(fd, offset, whence); |
| if (ret < 0) { |
| derror("seek failed: %s", strerror(errno)); |
| exit(1); |
| } |
| return ret; |
| } |
| |
| |
| typedef struct SnapshotInfo { |
| char *id_str; |
| char *name; |
| |
| uint32_t date_sec; |
| uint32_t date_nsec; |
| |
| uint64_t vm_clock_nsec; |
| uint32_t vm_state_size; |
| } SnapshotInfo; |
| |
| static SnapshotInfo* |
| snapshot_info_alloc() |
| { |
| return android_alloc(sizeof(SnapshotInfo)); |
| } |
| |
| static void |
| snapshot_info_free( SnapshotInfo* info ) |
| { |
| AFREE(info->id_str); |
| AFREE(info->name); |
| AFREE(info); |
| } |
| |
| |
| /* Reads a snapshot record from a qcow2-formatted file. |
| * |
| * The function assumes the file position of 'fd' points to the beginning of a |
| * QcowSnapshotHeader record. When the call returns, the file position of fd is |
| * at the place where the next QcowSnapshotHeader should start, if there is one. |
| * |
| * C.f. QCowSnapshotHeader in block/qcow2-snapshot.c for the complete layout of |
| * the header. |
| */ |
| static void |
| snapshot_info_read( int fd, SnapshotInfo* info ) |
| { |
| uint64_t start_offset = seek_or_die(fd, 0, SEEK_CUR); |
| |
| uint32_t extra_data_size; |
| uint16_t id_str_size, name_size; |
| |
| /* read fixed-length fields */ |
| seek_or_die(fd, 12, SEEK_CUR); /* skip l1 info */ |
| read_or_die(fd, &id_str_size, sizeof(id_str_size)); |
| read_or_die(fd, &name_size, sizeof(name_size)); |
| read_or_die(fd, &info->date_sec, sizeof(info->date_sec)); |
| read_or_die(fd, &info->date_nsec, sizeof(info->date_nsec)); |
| read_or_die(fd, &info->vm_clock_nsec, sizeof(info->vm_clock_nsec)); |
| read_or_die(fd, &info->vm_state_size, sizeof(info->vm_state_size)); |
| read_or_die(fd, &extra_data_size, sizeof(extra_data_size)); |
| |
| /* convert to host endianness */ |
| be16_to_cpus(&id_str_size); |
| be16_to_cpus(&name_size); |
| be32_to_cpus(&info->date_sec); |
| be32_to_cpus(&info->date_nsec); |
| be64_to_cpus(&info->vm_clock_nsec); |
| be32_to_cpus(&info->vm_state_size); |
| be32_to_cpus(&extra_data_size); |
| be32_to_cpus(&extra_data_size); |
| |
| /* read variable-length buffers*/ |
| info->id_str = android_alloc(id_str_size + 1); // +1: manual null-termination |
| info->name = android_alloc(name_size + 1); |
| seek_or_die(fd, extra_data_size, SEEK_CUR); /* skip extra data */ |
| read_or_die(fd, info->id_str, id_str_size); |
| read_or_die(fd, info->name, name_size); |
| |
| info->id_str[id_str_size] = '\0'; |
| info->name[name_size] = '\0'; |
| |
| /* headers are 8 byte aligned, ceil to nearest multiple of 8 */ |
| uint64_t end_offset = seek_or_die(fd, 0, SEEK_CUR); |
| uint32_t total_size = end_offset - start_offset; |
| uint32_t aligned_size = ((total_size - 1) / 8 + 1) * 8; |
| |
| /* skip to start of next record */ |
| seek_or_die(fd, start_offset + aligned_size, SEEK_SET); |
| } |
| |
| |
| #define NB_SUFFIXES 4 |
| |
| /* Returns the size of a snapshot in a human-readable format. |
| * |
| * This function copyright (c) 2003 Fabrice Bellard |
| */ |
| static char* |
| snapshot_format_size( char *buf, int buf_size, int64_t size ) |
| { |
| static const char suffixes[NB_SUFFIXES] = "KMGT"; |
| int64_t base; |
| int i; |
| |
| if (size <= 999) { |
| snprintf(buf, buf_size, "%" PRId64, size); |
| } else { |
| base = 1024; |
| for(i = 0; i < NB_SUFFIXES; i++) { |
| if (size < (10 * base)) { |
| snprintf(buf, buf_size, "%0.1f%c", |
| (double)size / base, |
| suffixes[i]); |
| break; |
| } else if (size < (1000 * base) || i == (NB_SUFFIXES - 1)) { |
| snprintf(buf, buf_size, "%" PRId64 "%c", |
| ((size + (base >> 1)) / base), |
| suffixes[i]); |
| break; |
| } |
| base = base * 1024; |
| } |
| } |
| return buf; |
| } |
| |
| static char* |
| snapshot_format_create_date( char *buf, size_t buf_size, time_t *time ) |
| { |
| struct tm *tm; |
| tm = localtime(time); |
| strftime(buf, buf_size, "%Y-%m-%d %H:%M:%S", tm); |
| return buf; |
| } |
| |
| static char* |
| snapshot_format_vm_clock( char *buf, size_t buf_size, uint64_t vm_clock_nsec ) |
| { |
| uint64_t secs = vm_clock_nsec / 1000000000; |
| snprintf(buf, buf_size, "%02d:%02d:%02d.%03d", |
| (int)(secs / 3600), |
| (int)((secs / 60) % 60), |
| (int)(secs % 60), |
| (int)((vm_clock_nsec / 1000000) % 1000)); |
| return buf; |
| } |
| |
| /* Prints a row of the snapshot table to stdout. */ |
| static void |
| snapshot_info_print( SnapshotInfo *info ) |
| { |
| char size_buf[8]; |
| char date_buf[21]; |
| char clock_buf[21]; |
| |
| snapshot_format_size(size_buf, sizeof(size_buf), info->vm_state_size); |
| snapshot_format_create_date(date_buf, sizeof(date_buf), |
| (time_t*) &info->date_sec); |
| snapshot_format_vm_clock(clock_buf, sizeof(clock_buf), info->vm_clock_nsec); |
| |
| printf(" %-10s%-20s%7s%20s%15s\n", |
| info->id_str, info->name, size_buf, date_buf, clock_buf); |
| } |
| |
| /* Prints table of all snapshots recorded in the file 'fd'. |
| */ |
| static void |
| snapshot_print_table( int fd, uint32_t nb_snapshots, uint64_t snapshots_offset ) |
| { |
| printf(" %-10s%-20s%7s%20s%15s\n", |
| "ID", "TAG", "VM SIZE", "DATE", "VM CLOCK"); |
| |
| /* skip ahead to snapshot data */ |
| seek_or_die(fd, snapshots_offset, SEEK_SET); |
| |
| /* iterate over snapshot records */ |
| int i; |
| for (i = 0; i < nb_snapshots; i++) { |
| SnapshotInfo *info = snapshot_info_alloc(); |
| snapshot_info_read(fd, info); |
| snapshot_info_print(info); |
| |
| snapshot_info_free(info); |
| } |
| } |
| |
| /* Validates that 'fd' starts with a correct Qcow 2 header. Prints an error and |
| * exit()s if validation fails. |
| */ |
| static void |
| snapshot_validate_qcow_file( int fd ) |
| { |
| /* read magic number and qcow version (2x4 bytes) */ |
| uint32_t magic, version; |
| read_or_die(fd, &magic, sizeof(magic)); |
| read_or_die(fd, &version, sizeof(version)); |
| be32_to_cpus(&magic); |
| be32_to_cpus(&version); |
| |
| if (magic != QCOW_MAGIC) { |
| derror("Not a valid Qcow snapshot file (expected magic value '%08x', got '%08x').", |
| QCOW_MAGIC, magic); |
| exit(1); |
| } |
| if (version != QCOW_VERSION) { |
| derror("Unsupported Qcow version (need %d, got %d).", |
| QCOW_VERSION, version); |
| exit(1); |
| } |
| } |
| |
| /* Reads snapshot information from a Qcow2 file header. |
| * |
| * C.f. QCowHeader in block/qcow2.h for an exact listing of the header |
| * contents. |
| */ |
| static void |
| snapshot_read_qcow_header( int fd, uint32_t *nb_snapshots, uint64_t *snapshots_offset ) |
| { |
| snapshot_validate_qcow_file(fd); |
| |
| /* skip non-snapshot related metadata (4x8 + 5x4 = 52 bytes)*/ |
| seek_or_die(fd, 52, SEEK_CUR); |
| |
| read_or_die(fd, nb_snapshots, sizeof(*nb_snapshots)); |
| read_or_die(fd, snapshots_offset, sizeof(*snapshots_offset)); |
| |
| /* convert to host endianness */ |
| be32_to_cpus(nb_snapshots); |
| be64_to_cpus(snapshots_offset); |
| } |
| |
| /* Prints a table with information on the snapshots in the qcow2-formatted file |
| * 'snapstorage', then exit()s. |
| */ |
| void |
| snapshot_print_and_exit( const char *snapstorage ) |
| { |
| /* open snapshot file */ |
| int fd = open(snapstorage, O_RDONLY); |
| if (!fd) { |
| derror("Could not open snapshot file '%s': %s", snapstorage, strerror(errno)); |
| exit(1); |
| } |
| |
| /* read snapshot info from file header */ |
| uint32_t nb_snapshots; |
| uint64_t snapshots_offset; |
| snapshot_read_qcow_header(fd, &nb_snapshots, &snapshots_offset); |
| |
| if (nb_snapshots > 0) { |
| printf("Snapshots in file '%s':\n", snapstorage); |
| snapshot_print_table(fd, nb_snapshots, snapshots_offset); |
| } |
| else { |
| printf("File '%s' contains no snapshots yet.\n", snapstorage); |
| } |
| |
| close(fd); |
| exit(0); |
| } |
| #endif // CONFIG_ANDROID_SNAPSHOTS |