From: Po Lu <luangruo@yahoo.com>
Date: Fri, 5 May 2023 04:10:14 +0000 (+0800)
Subject: Update Android port
X-Git-Url: http://git.eshelyaron.com/gitweb/?a=commitdiff_plain;h=2ba6c5035c904426d564eac47381480158cbbb9e;p=emacs.git

Update Android port

* doc/emacs/android.texi (Android Environment): Document lossage
with SIGSTOP.
* exec/exec.c (exec_0): Check X_OK on file being opened.  Also
handle /proc/self/exe.
---

diff --git a/doc/emacs/android.texi b/doc/emacs/android.texi
index f2bcc50df23..d7fadd69e4b 100644
--- a/doc/emacs/android.texi
+++ b/doc/emacs/android.texi
@@ -293,6 +293,11 @@ loader.  As a result, @code{interrupt-process}, and other related
 functions will work correctly, but using the process ID returned by
 @code{process-id} for other purposes will not.
 
+  One side effect of the mechanism by which process tracing is carried
+out is that job control facilities will not be able to stop
+subprocesses, and the @code{SIGSTOP} signal will appear to have no
+effect.
+
   In addition, Android 12 also terminates subprocesses which are
 consuming CPU while Emacs itself is in the background.  The system
 determines which processes are consuming too much CPU in intervals of
diff --git a/exec/exec.c b/exec/exec.c
index 17051428658..a15386b51bb 100644
--- a/exec/exec.c
+++ b/exec/exec.c
@@ -961,52 +961,68 @@ exec_0 (char *name, struct exec_tracee *tracee,
   ssize_t link_size;
   size_t remaining;
 
-  /* If name is not absolute, then make it relative to TRACEE's
-     cwd.  Use stpcpy, as sprintf is not reentrant.  */
+  /* If the process is trying to run /proc/self/exe, make it run
+     itself instead.  */
 
-  if (name[0] && name[0] != '/')
+  if (!strcmp (name, "/proc/self/exe") && tracee->exec_file)
     {
-      /* Clear `buffer'.  */
-      memset (buffer, 0, sizeof buffer);
-      memset (buffer1, 0, sizeof buffer);
+      strncpy (name, tracee->exec_file, PATH_MAX - 1);
+      name[PATH_MAX] = '\0';
+    }
+  else
+    {
+      /* If name is not absolute, then make it relative to TRACEE's
+	 cwd.  Use stpcpy, as sprintf is not reentrant.  */
 
-      /* Copy over /proc, the PID, and /cwd/.  */
-      rewrite = stpcpy (buffer, "/proc/");
-      rewrite = format_pid (rewrite, tracee->pid);
-      stpcpy (rewrite, "/cwd");
+      if (name[0] && name[0] != '/')
+	{
+	  /* Clear `buffer'.  */
+	  memset (buffer, 0, sizeof buffer);
+	  memset (buffer1, 0, sizeof buffer);
 
-      /* Resolve this symbolic link.  */
+	  /* Copy over /proc, the PID, and /cwd/.  */
+	  rewrite = stpcpy (buffer, "/proc/");
+	  rewrite = format_pid (rewrite, tracee->pid);
+	  stpcpy (rewrite, "/cwd");
 
-      link_size = readlink (buffer, buffer1,
-			    PATH_MAX + 1);
+	  /* Resolve this symbolic link.  */
 
-      if (link_size < 0)
-	return NULL;
+	  link_size = readlink (buffer, buffer1,
+				PATH_MAX + 1);
 
-      /* Check that the name is a reasonable size.  */
+	  if (link_size < 0)
+	    return NULL;
 
-      if (link_size > PATH_MAX)
-	{
-	  /* The name is too long.  */
-	  errno = ENAMETOOLONG;
-	  return NULL;
-	}
+	  /* Check that the name is a reasonable size.  */
+
+	  if (link_size > PATH_MAX)
+	    {
+	      /* The name is too long.  */
+	      errno = ENAMETOOLONG;
+	      return NULL;
+	    }
 
-      /* Add a directory separator if necessary.  */
+	  /* Add a directory separator if necessary.  */
       
-      if (!link_size || buffer1[link_size - 1] != '/')
-	buffer1[link_size] = '/', link_size++;
+	  if (!link_size || buffer1[link_size - 1] != '/')
+	    buffer1[link_size] = '/', link_size++;
 
-      rewrite = buffer1 + link_size;
-      remaining = buffer1 + sizeof buffer1 - rewrite - 1;
-      rewrite = stpncpy (rewrite, name, remaining);
+	  rewrite = buffer1 + link_size;
+	  remaining = buffer1 + sizeof buffer1 - rewrite - 1;
+	  rewrite = stpncpy (rewrite, name, remaining);
 
-      /* Replace name with buffer1.  */
+	  /* Replace name with buffer1.  */
 #ifndef REENTRANT
-      strcpy (name, buffer1);
+	  strcpy (name, buffer1);
 #endif /* REENTRANT */
+	}
     }
 
+  /* Check that the file is accessible and executable.  */
+
+  if (access (name, X_OK))
+    return NULL;
+
   fd = open (name, O_RDONLY);
   if (fd < 0)
     return NULL;