From 3b34b85cc88667a7d1f13e6c82cf478a5009fb3f Mon Sep 17 00:00:00 2001
From: Po Lu <luangruo@yahoo.com>
Date: Wed, 9 Aug 2023 14:23:25 +0800
Subject: [PATCH] Fix crashes runninging android-emacs with bad LD_LIBRARY_PATH

* doc/emacs/input.texi (Touchscreens, On-Screen Keyboards): Fix
section titles.

* src/android-emacs.c (main): If EMACS_LD_LIBRARY_PATH is set,
make it LD_LIBRARY_PATH.

* src/android.c (JNICALL): Set LD_LIBRARY_PATH as well as
EMACS_LD_LIBRARY_PATH.
---
 doc/emacs/input.texi |  4 ++--
 src/android-emacs.c  | 25 +++++++++++++++++--------
 src/android.c        |  6 ++++++
 3 files changed, 25 insertions(+), 10 deletions(-)

diff --git a/doc/emacs/input.texi b/doc/emacs/input.texi
index 671901fea88..4f49ca3cece 100644
--- a/doc/emacs/input.texi
+++ b/doc/emacs/input.texi
@@ -20,7 +20,7 @@ which is detailed here.
 @end menu
 
 @node Touchscreens
-@section Using Emacs on touchscreens
+@section Using Emacs on Touchscreens
 @cindex touchscreen input
 
   Touchscreen input works by pressing and moving tools (which include
@@ -97,7 +97,7 @@ this can be changed by customizing the variable
 @code{touch-screen-delay}.
 
 @node On-Screen Keyboards
-@section Using Emacs with virtual keyboards
+@section Using Emacs with Virtual Keyboards
 @cindex virtual keyboards
 @cindex on-screen keyboards
 
diff --git a/src/android-emacs.c b/src/android-emacs.c
index e64caf9a9d4..2c405795860 100644
--- a/src/android-emacs.c
+++ b/src/android-emacs.c
@@ -37,7 +37,7 @@ main (int argc, char **argv)
 {
   char **args;
   int i;
-  char *bootclasspath, *emacs_class_path;
+  char *bootclasspath, *emacs_class_path, *ld_library_path;
 
   /* Allocate enough to hold the arguments to app_process.  */
   args = alloca ((10 + argc) * sizeof *args);
@@ -46,11 +46,11 @@ main (int argc, char **argv)
   memset (args, 0, (10 + argc) * sizeof *args);
 
   /* First, figure out what program to start.  */
-#if defined __x86_64__ || defined __aarch64__
+#if defined __x86_64__ || defined __aarch64__ || defined __mips64
   args[0] = (char *) "/system/bin/app_process64";
-#else
+#else /* i386 || regular mips || arm */
   args[0] = (char *) "/system/bin/app_process";
-#endif
+#endif /* __x86_64__ || __aarch64__ || __mips64 */
 
   /* Machines with ART require the boot classpath to be manually
      specified.  Machines with Dalvik however refuse to do so, as they
@@ -72,13 +72,13 @@ main (int argc, char **argv)
       bootclasspath = NULL;
       goto skip_setup;
     }
-#else
+#else /* !HAVE_DECL_ANDROID_GET_DEVICE_API_LEVEL */
   if (__ANDROID_API__ < 21)
     {
       bootclasspath = NULL;
       goto skip_setup;
     }
-#endif
+#endif /* HAVE_DECL_ANDROID_GET_DEVICE_API_LEVEL */
 
   /* Next, obtain the boot class path.  */
   bootclasspath = getenv ("BOOTCLASSPATH");
@@ -106,6 +106,15 @@ main (int argc, char **argv)
       return 1;
     }
 
+  /* Restore LD_LIBRARY_PATH to its original value, the app library
+     directory, to guarantee that it is possible for Java to find the
+     Emacs C code later.  */
+
+  ld_library_path = getenv ("EMACS_LD_LIBRARY_PATH");
+
+  if (ld_library_path)
+    setenv ("LD_LIBRARY_PATH", ld_library_path, 1);
+
   if (bootclasspath)
     {
       if (asprintf (&bootclasspath, "-Djava.class.path=%s:%s",
@@ -146,7 +155,7 @@ main (int argc, char **argv)
     }
   else
     {
-#endif
+#endif /* HAVE_DECL_ANDROID_GET_DEVICE_API_LEVEL */
       args[3] = (char *) "org.gnu.emacs.EmacsNoninteractive";
 
       /* Arguments from here on are passed to main in
@@ -158,7 +167,7 @@ main (int argc, char **argv)
 	args[4 + i] = argv[i];
 #if HAVE_DECL_ANDROID_GET_DEVICE_API_LEVEL
     }
-#endif
+#endif /* HAVE_DECL_ANDROID_GET_DEVICE_API_LEVEL */
 
   /* Finally, try to start the app_process.  */
   execvp (args[0], args);
diff --git a/src/android.c b/src/android.c
index 705ef227df3..b5b4359dcd3 100644
--- a/src/android.c
+++ b/src/android.c
@@ -1424,6 +1424,12 @@ NATIVE_NAME (setEmacsParams) (JNIEnv *env, jobject object,
   /* Set LD_LIBRARY_PATH to an appropriate value.  */
   setenv ("LD_LIBRARY_PATH", android_lib_dir, 1);
 
+  /* EMACS_LD_LIBRARY_PATH records the location of the app library
+     directory.  android-emacs refers to this, since users have valid
+     reasons for changing LD_LIBRARY_PATH to a value that precludes
+     the possibility of Java locating libemacs later.  */
+  setenv ("EMACS_LD_LIBRARY_PATH", android_lib_dir, 1);
+
   /* Make a reference to the Emacs service.  */
 
   if (emacs_service_object)
-- 
2.39.2