1 files changed, 19 insertions, 1 deletions

diff --git a/recovery.cpp b/recovery.cpp
index a84d8333a..840e63c42 100644
--- a/recovery.cpp
+++ b/recovery.cpp
@@ -59,10 +59,11 @@ static const struct option OPTIONS[] = {
   { NULL, 0, NULL, 0 },
 };
 
+#define LAST_LOG_FILE "/cache/recovery/last_log"
+
 static const char *COMMAND_FILE = "/cache/recovery/command";
 static const char *INTENT_FILE = "/cache/recovery/intent";
 static const char *LOG_FILE = "/cache/recovery/log";
-static const char *LAST_LOG_FILE = "/cache/recovery/last_log";
 static const char *LAST_INSTALL_FILE = "/cache/recovery/last_install";
 static const char *LOCALE_FILE = "/cache/recovery/last_locale";
 static const char *CACHE_ROOT = "/cache";
@@ -260,6 +261,21 @@ copy_log_file(const char* source, const char* destination, int append) {
     }
 }
 
+// Rename last_log -> last_log.1 -> last_log.2 -> ... -> last_log.$max
+// Overwrites any existing last_log.$max.
+static void
+rotate_last_logs(int max) {
+    char oldfn[256];
+    char newfn[256];
+
+    int i;
+    for (i = max-1; i >= 0; --i) {
+        snprintf(oldfn, sizeof(oldfn), (i==0) ? LAST_LOG_FILE : (LAST_LOG_FILE ".%d"), i);
+        snprintf(newfn, sizeof(newfn), LAST_LOG_FILE ".%d", i+1);
+        // ignore errors
+        rename(oldfn, newfn);
+    }
+}
 
 // clear the recovery command and prepare to boot a (hopefully working) system,
 // copy our log file to cache as well (for the system to read), and
@@ -843,6 +859,8 @@ main(int argc, char **argv) {
     printf("Starting recovery on %s", ctime(&start));
 
     load_volume_table();
+    ensure_path_mounted(LAST_LOG_FILE);
+    rotate_last_logs(5);
     get_args(&argc, &argv);
 
     int previous_runs = 0;