Fix -snapshot-list option.

This patch makes -snapshot-list work properly. More specifically:

- If the AVD has snapshotting enabled, the emulator will find the
  appropriate file if you don't use -snapstorage.

- If the AVD has no snapshot support, the emulator will print
  a user-friendly message to explain that.

- If you're in the Android build, the emulator indicates that
  -snapstorage <file> is mandatory.

Bug 4384430

Change-Id: I472b12f50b7f7da5a282b24036083c7598fe48eb

2 files changed, 16 insertions, 1 deletions

diff --git a/android/main.c b/android/main.c
index 0682497..aa3ee46 100644
--- a/android/main.c
+++ b/android/main.c
@@ -261,6 +261,21 @@ int main(int argc, char **argv)
     }
 
     if (opts->snapshot_list) {
+        if (opts->snapstorage == NULL) {
+            /* Need to find the default snapstorage */
+            avd = createAVD(opts, &inAndroidBuild);
+            opts->snapstorage = avdInfo_getSnapStoragePath(avd);
+            if (opts->snapstorage != NULL) {
+                D("autoconfig: -snapstorage %s", opts->snapstorage);
+            } else {
+                if (inAndroidBuild) {
+                    derror("You must use the -snapstorage <file> option to specify a snapshot storage file!\n");
+                } else {
+                    derror("This AVD doesn't have snapshotting enabled!\n");
+                }
+                exit(1);
+            }
+        }
         snapshot_print_and_exit(opts->snapstorage);
     }
 
diff --git a/android/snapshot.c b/android/snapshot.c
index 047465f..d02d9a8 100644
--- a/android/snapshot.c
+++ b/android/snapshot.c
@@ -310,7 +310,7 @@ snapshot_print_and_exit( const char *snapstorage )
 {
     /* open snapshot file */
     int fd = open(snapstorage, O_RDONLY);
-    if (!fd) {
+    if (fd < 0) {
         derror("Could not open snapshot file '%s': %s", snapstorage, strerror(errno));
         exit(1);
     }