recovery: turn on text display for install errors in debug builds

Hopefully this will reduce the number of OTA "bugs" reported that are
really just someone having changed their system partition,
invalidating future incremental OTAs.

Also fixes a longstanding TODO about putting LOGE() output in the
on-screen display.

Change-Id: I44e5be65b2dee7ebce2cce28ccd920dc3d6e522e
diff --git a/recovery.cpp b/recovery.cpp
index 7002cb8..a84d833 100644
--- a/recovery.cpp
+++ b/recovery.cpp
@@ -15,11 +15,13 @@
  */
 
 #include <ctype.h>
+#include <dirent.h>
 #include <errno.h>
 #include <fcntl.h>
 #include <getopt.h>
 #include <limits.h>
 #include <linux/input.h>
+#include <stdarg.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -27,7 +29,6 @@
 #include <sys/types.h>
 #include <time.h>
 #include <unistd.h>
-#include <dirent.h>
 
 #include "bootloader.h"
 #include "common.h"
@@ -801,6 +802,24 @@
     }
 }
 
+static RecoveryUI* gCurrentUI = NULL;
+
+void
+ui_print(const char* format, ...) {
+    char buffer[256];
+
+    va_list ap;
+    va_start(ap, format);
+    vsnprintf(buffer, sizeof(buffer), format, ap);
+    va_end(ap);
+
+    if (gCurrentUI != NULL) {
+        gCurrentUI->Print("%s", buffer);
+    } else {
+        fputs(buffer, stdout);
+    }
+}
+
 int
 main(int argc, char **argv) {
     time_t start = time(NULL);
@@ -856,6 +875,7 @@
 
     Device* device = make_device();
     ui = device->GetUI();
+    gCurrentUI = ui;
 
     ui->Init();
     ui->SetLocale(locale);
@@ -909,7 +929,18 @@
                 LOGE("Cache wipe (requested by package) failed.");
             }
         }
-        if (status != INSTALL_SUCCESS) ui->Print("Installation aborted.\n");
+        if (status != INSTALL_SUCCESS) {
+            ui->Print("Installation aborted.\n");
+
+            // If this is an eng or userdebug build, then automatically
+            // turn the text display on if the script fails so the error
+            // message is visible.
+            char buffer[PROPERTY_VALUE_MAX+1];
+            property_get("ro.build.fingerprint", buffer, "");
+            if (strstr(buffer, ":userdebug/") || strstr(buffer, ":eng/")) {
+                ui->ShowText(true);
+            }
+        }
     } else if (wipe_data) {
         if (device->WipeData()) status = INSTALL_ERROR;
         if (erase_volume("/data")) status = INSTALL_ERROR;