5 files changed, 117 insertions, 6 deletions

diff --git a/bootloader.c b/bootloader.c
index bc79bee76..61b24e918 100644
--- a/bootloader.c
+++ b/bootloader.c
@@ -155,10 +155,14 @@ struct update_header {
     unsigned fail_bitmap_length;
 };
 
+#define LOG_MAGIC        "LOGmagic"
+#define LOG_MAGIC_SIZE   8
+
 int write_update_for_bootloader(
         const char *update, int update_length,
         int bitmap_width, int bitmap_height, int bitmap_bpp,
-        const char *busy_bitmap, const char *fail_bitmap) {
+        const char *busy_bitmap, const char *fail_bitmap,
+        const char *log_filename) {
     if (ensure_root_path_unmounted(CACHE_NAME)) {
         LOGE("Can't unmount %s\n", CACHE_NAME);
         return -1;
@@ -198,6 +202,21 @@ int write_update_for_bootloader(
     header.version = UPDATE_VERSION;
     header.size = header_size;
 
+    if (log_filename != NULL) {
+        // Write 1 byte into the following block, then fill to the end
+        // in order to reserve that block.  We'll use the block to
+        // send a copy of the log through to the next invocation of
+        // recovery.  We write the log as late as possible in order to
+        // capture any messages emitted by this function.
+        mtd_erase_blocks(write, 0);
+        if (mtd_write_data(write, (char*) &header, 1) != 1) {
+            LOGE("Can't write log block to %s\n(%s)\n",
+                 CACHE_NAME, strerror(errno));
+            mtd_write_close(write);
+            return -1;
+        }
+    }
+
     off_t image_start_pos = mtd_erase_blocks(write, 0);
     header.image_length = update_length;
     if ((int) header.image_offset == -1 ||
@@ -256,6 +275,37 @@ int write_update_for_bootloader(
         return -1;
     }
 
+    if (log_filename != NULL) {
+        size_t erase_size;
+        if (mtd_partition_info(part, NULL, &erase_size, NULL) != 0) {
+            LOGE("Error reading block size\n(%s)\n", strerror(errno));
+            mtd_write_close(write);
+            return -1;
+        }
+        mtd_erase_blocks(write, 0);
+
+        if (erase_size > 0) {
+            char* log = malloc(erase_size);
+            FILE* f = fopen(log_filename, "rb");
+            // The fseek() may fail if it tries to go before the
+            // beginning of the log, but that's okay because we want
+            // to be positioned at the start anyway.
+            fseek(f, -(erase_size-sizeof(size_t)-LOG_MAGIC_SIZE), SEEK_END);
+            memcpy(log, LOG_MAGIC, LOG_MAGIC_SIZE);
+            size_t read = fread(log+sizeof(size_t)+LOG_MAGIC_SIZE,
+                                1, erase_size-sizeof(size_t)-LOG_MAGIC_SIZE, f);
+            LOGI("read %d bytes from log\n", (int)read);
+            *(size_t *)(log + LOG_MAGIC_SIZE) = read;
+            fclose(f);
+            if (mtd_write_data(write, log, erase_size) != erase_size) {
+                LOGE("failed to store log in cache partition\n(%s)\n",
+                     strerror(errno));
+                mtd_write_close(write);
+            }
+            free(log);
+        }
+    }
+
     if (mtd_erase_blocks(write, 0) != image_start_pos) {
         LOGE("Misalignment rewriting %s\n(%s)\n", CACHE_NAME, strerror(errno));
         mtd_write_close(write);
@@ -269,3 +319,52 @@ int write_update_for_bootloader(
 
     return 0;
 }
+
+void recover_firmware_update_log() {
+    printf("recovering log from before firmware update\n");
+
+    const MtdPartition *part = get_root_mtd_partition(CACHE_NAME);
+    if (part == NULL) {
+        LOGE("Can't find %s\n", CACHE_NAME);
+        return;
+    }
+
+    MtdReadContext* read = mtd_read_partition(part);
+
+    size_t erase_size;
+    if (mtd_partition_info(part, NULL, &erase_size, NULL) != 0) {
+        LOGE("Error reading block size\n(%s)\n", strerror(errno));
+        mtd_read_close(read);
+        return;
+    }
+
+    char* buffer = malloc(erase_size);
+    if (mtd_read_data(read, buffer, erase_size) != erase_size) {
+        LOGE("Error reading header block\n(%s)\n", strerror(errno));
+        mtd_read_close(read);
+        free(buffer);
+        return;
+    }
+    if (mtd_read_data(read, buffer, erase_size) != erase_size) {
+        LOGE("Error reading log block\n(%s)\n", strerror(errno));
+        mtd_read_close(read);
+        free(buffer);
+        return;
+    }
+    mtd_read_close(read);
+
+    if (memcmp(buffer, LOG_MAGIC, LOG_MAGIC_SIZE) != 0) {
+        LOGE("No log from before firmware install\n");
+        free(buffer);
+        return;
+    }
+
+    size_t log_size = *(size_t *)(buffer + LOG_MAGIC_SIZE);
+    LOGI("header has %d bytes of log\n", (int)log_size);
+
+    printf("\n###\n### START RECOVERED LOG\n###\n\n");
+    fwrite(buffer + sizeof(size_t) + LOG_MAGIC_SIZE, 1, log_size, stdout);
+    printf("\n\n###\n### END RECOVERED LOG\n###\n\n");
+
+    free(buffer);
+}
diff --git a/bootloader.h b/bootloader.h
index 3d4302f1e..fec6409ff 100644
--- a/bootloader.h
+++ b/bootloader.h
@@ -54,6 +54,13 @@ int set_bootloader_message(const struct bootloader_message *in);
 int write_update_for_bootloader(
         const char *update, int update_len,
         int bitmap_width, int bitmap_height, int bitmap_bpp,
-        const char *busy_bitmap, const char *error_bitmap);
+        const char *busy_bitmap, const char *error_bitmap,
+        const char *log_filename);
+
+/* Look for a log stored in the cache partition in the block after the
+ * firmware update header.  If we can read such a log, copy it to
+ * stdout (ie, the current log).
+ */
+void recover_firmware_update_log();
 
 #endif
diff --git a/firmware.c b/firmware.c
index e2e4fe630..6739c1e93 100644
--- a/firmware.c
+++ b/firmware.c
@@ -76,7 +76,8 @@ int firmware_update_pending() {
  * It is recovery's responsibility to clean up the mess afterwards.
  */
 
-int maybe_install_firmware_update(const char *send_intent) {
+int maybe_install_firmware_update(const char *send_intent,
+                                  const char *log_filename) {
     if (update_data == NULL || update_length == 0) return 0;
 
     /* We destroy the cache partition to pass the update image to the
@@ -104,7 +105,7 @@ int maybe_install_firmware_update(const char *send_intent) {
     ui_print("Writing %s image...\n", update_type);
     if (write_update_for_bootloader(
             update_data, update_length,
-            width, height, bpp, busy_image, fail_image)) {
+            width, height, bpp, busy_image, fail_image, log_filename)) {
         LOGE("Can't write %s image\n(%s)\n", update_type, strerror(errno));
         format_root_device("CACHE:");  // Attempt to clean cache up, at least.
         return -1;
@@ -118,6 +119,7 @@ int maybe_install_firmware_update(const char *send_intent) {
      * wipe the cache and reboot into the system.)
      */
     snprintf(boot.command, sizeof(boot.command), "update-%s", update_type);
+    strlcat(boot.recovery, "--recover_log\n", sizeof(boot.recovery));
     if (set_bootloader_message(&boot)) {
         format_root_device("CACHE:");
         return -1;
diff --git a/firmware.h b/firmware.h
index aeb8f97aa..04507bbf0 100644
--- a/firmware.h
+++ b/firmware.h
@@ -30,6 +30,7 @@ int firmware_update_pending();
  * Returns 0 if no radio image was defined, nonzero on error,
  * doesn't return at all on success...
  */
-int maybe_install_firmware_update(const char *send_intent);
+int maybe_install_firmware_update(const char *send_intent,
+                                  const char *log_filename);
 
 #endif
diff --git a/recovery.c b/recovery.c
index 58c84ef2f..1a885602d 100644
--- a/recovery.c
+++ b/recovery.c
@@ -46,6 +46,7 @@ static const struct option OPTIONS[] = {
   { "wipe_cache", no_argument, NULL, 'c' },
   // TODO{oam}: implement improved command line passing key, egnot to review.
   { "set_encrypted_filesystem", required_argument, NULL, 'e' },
+  { "recover_log", no_argument, NULL, 'g' },
   { NULL, 0, NULL, 0 },
 };
 
@@ -491,6 +492,7 @@ main(int argc, char **argv) {
         case 'w': wipe_data = wipe_cache = 1; break;
         case 'c': wipe_cache = 1; break;
         case 'e': efs_mode = optarg; toggle_efs = 1; break;
+        case 'g': recover_firmware_update_log(); break;
         case '?':
             LOGE("Invalid command argument\n");
             continue;
@@ -562,7 +564,7 @@ main(int argc, char **argv) {
     if (status != INSTALL_SUCCESS || ui_text_visible()) prompt_and_wait();
 
     // If there is a radio image pending, reboot now to install it.
-    maybe_install_firmware_update(send_intent);
+    maybe_install_firmware_update(send_intent, TEMPORARY_LOG_FILE);
 
     // Otherwise, get ready to boot the main system...
     finish_recovery(send_intent);