Merge "Add command line flag to show list of snapshots."

6 files changed, 394 insertions, 3 deletions

diff --git a/Makefile.android b/Makefile.android
index 1cc904a..1d82197 100644
--- a/Makefile.android
+++ b/Makefile.android
@@ -693,6 +693,7 @@ CORE_MISC_SOURCES = vl-android.c \
                     android/hw-qemud.c \
                     android/core-init-utils.c   \
                     android/config.c \
+                    android/snapshot.c \
 
 ifeq ($(HOST_ARCH),x86)
     CORE_MISC_SOURCES += i386-dis.c
@@ -1181,6 +1182,7 @@ VL_SOURCES := framebuffer.c \
               android/cmdline-option.c \
               android/config.c \
               android/display.c \
+              android/snapshot.c \
               android/main.c \
               qemu-timer-ui.c \
               vl-android-ui.c \
diff --git a/android/cmdline-options.h b/android/cmdline-options.h
index a9b02ac..da8f375 100644
--- a/android/cmdline-options.h
+++ b/android/cmdline-options.h
@@ -81,6 +81,7 @@ OPT_PARAM( snapstorage,    "<file>", "file that contains all state snapshots (de
 OPT_FLAG ( no_snapstorage, "do not mount a snapshot storage file (this disables all snapshot functionality)" )
 OPT_PARAM( snapshot,       "<name>", "immediately load state snapshot rather than doing a full boot (default 'default-boot')" )
 OPT_FLAG ( no_snapshot,    "do not start from snapshot, but perform a full boot sequence" )
+OPT_FLAG ( snapshot_list,  "show a list of available snapshots" )
 #endif
 OPT_FLAG ( wipe_data, "reset the use data image (copy it from initdata)" )
 CFG_PARAM( avd, "<name>", "use a specific android virtual device" )
diff --git a/android/help.c b/android/help.c
index 17e7a90..f589b3e 100644
--- a/android/help.c
+++ b/android/help.c
@@ -700,6 +700,21 @@ help_no_snapshot(stralloc_t*  out)
     );
 }
 
+static void
+help_snapshot_list(stralloc_t*  out)
+{
+    PRINTF(
+    "  This prints a table of snapshots that are stored in the snapshot storage\n"
+    "  file that the emulator was started with, then exits. Values from the 'ID'\n"
+    "  and 'TAG' columns can be used as arguments for the '-snapshot' parameter.\n\n"
+
+    "  If '-snapstorage <file>' was specified as well, this command prints a "
+    "  table of the snapshots stored in <file>.\n\n"
+
+    "  See '-help-snapshot' for more information on snapshots.\n\n"
+    );
+}
+
 #endif
 
 static void
diff --git a/android/main.c b/android/main.c
index a328ad1..6b3bea6 100644
--- a/android/main.c
+++ b/android/main.c
@@ -59,6 +59,8 @@
 #include "android/qemulator.h"
 #include "android/display.h"
 
+#include "android/snapshot.h"
+
 #include "framebuffer.h"
 
 AndroidRotation  android_framebuffer_rotation;
@@ -1003,11 +1005,11 @@ int main(int argc, char **argv)
         if (!opts->snapstorage && opts->datadir) {
             bufprint(tmp, tmpend, "%s/snapshots.img", opts->datadir);
             if (path_exists(tmp)) {
-                opts->snapstorage = qemu_strdup(tmp);
+                opts->snapstorage = android_strdup(tmp);
                 D("autoconfig: -snapstorage %s", opts->snapstorage);
             }
         }
-#endif
+#endif // CONFIG_ANDROID_SNAPSHOTS
     }
 
     /* setup the virtual device parameters from our options
@@ -1423,7 +1425,11 @@ int main(int argc, char **argv)
     } else if (opts->no_snapshot) {
         D("ignoring redundant option '-no-snapshot' implied by '-no-snapstorage'");
     }
-#endif
+
+    if (opts->snapshot_list) {
+        snapshot_print_and_exit(opts->snapstorage);
+    }
+#endif // CONFIG_ANDROID_SNAPSHOTS
 
     if (!opts->logcat || opts->logcat[0] == 0) {
         opts->logcat = getenv("ANDROID_LOG_TAGS");
diff --git a/android/snapshot.c b/android/snapshot.c
new file mode 100644
index 0000000..ca86700
--- /dev/null
+++ b/android/snapshot.c
@@ -0,0 +1,336 @@
+/*
+ * 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
diff --git a/android/snapshot.h b/android/snapshot.h
new file mode 100644
index 0000000..be03818
--- /dev/null
+++ b/android/snapshot.h
@@ -0,0 +1,31 @@
+/*
+ * 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.
+ */
+
+#ifndef SNAPSHOTS_H_
+#define SNAPSHOTS_H_
+
+#include "config/config.h"
+
+#if CONFIG_ANDROID_SNAPSHOTS
+
+/* Prints a table with information on the snapshot stored in the file
+ * 'snapstorage', then exit()s.
+ */
+void snapshot_print_and_exit( const char *snapstorage );
+
+#endif
+
+#endif /* SNAPSHOTS_H_ */