Re: [PATCH] Fix gdb crash due to SIGPIPE when the compile command fails

[Bernd Edlinger <bernd.edlinger@hotmail.de>]

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On 6/4/21 3:39 PM, Tom Tromey wrote:
>>>>>> "Bernd" == Bernd Edlinger <bernd.edlinger@hotmail.de> writes:
> 
> Bernd> I believe it is right to avoid the SIGPIPE before calling the plugin,
> Bernd> instead of doing that in gcc-trunk, since we don't know which version
> Bernd> we will be calling, and all versions I tried have failed like this.
> 
> That seems fine, but I think it would be better to install the handler
> just when working with the plugin, and then uninstall it afterward, sort
> of like what class scoped_ignore_sigttou does.
> 

Okay, done, that works for me.

Is this OK?


Thanks
Bernd.


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From 3bb3966601a89c18ea2700c3eae4aa4f4e195269 Mon Sep 17 00:00:00 2001
From: Bernd Edlinger <bernd.edlinger@hotmail.de>
Date: Wed, 2 Jun 2021 19:21:15 +0200
Subject: [PATCH] Fix gdb crash due to SIGPIPE when the compile command fails

Due to the SIGPIPE the gdb process is killed here, which is
not helpful.

2021-06-02  Bernd Edlinger  <bernd.edlinger@hotmail.de>

	* compile/compile.c (compile_to_object): Ignore SIGPIPE before calling
	the plugin.
---
 gdb/compile/compile.c | 31 +++++++++++++++++++++++++++++++
 1 file changed, 31 insertions(+)

diff --git a/gdb/compile/compile.c b/gdb/compile/compile.c
index 8481d14..3431d4c 100644
--- a/gdb/compile/compile.c
+++ b/gdb/compile/compile.c
@@ -633,6 +633,33 @@ struct compile_options
   fputs_filtered (message, gdb_stderr);
 }
 
+/* RAII class used to ignore SIGPIPE in a scope.  */
+
+class scoped_ignore_sigpipe
+{
+public:
+  scoped_ignore_sigpipe ()
+  {
+#ifdef SIGPIPE
+    m_osigpipe = signal (SIGPIPE, SIG_IGN);
+#endif
+  }
+
+  ~scoped_ignore_sigpipe ()
+  {
+#ifdef SIGTTOU
+    signal (SIGPIPE, m_osigpipe);
+#endif
+  }
+
+  DISABLE_COPY_AND_ASSIGN (scoped_ignore_sigpipe);
+
+private:
+#ifdef SIGPIPE
+  sighandler_t m_osigpipe = NULL;
+#endif
+};
+
 /* Process the compilation request.  On success it returns the object
    and source file names.  On an error condition, error () is
    called.  */
@@ -755,6 +782,10 @@ struct compile_options
     fprintf_unfiltered (gdb_stdlog, "source file produced: %s\n\n",
 			fnames.source_file ());
 
+  /* If we don't do this, then GDB simply exits
+     when the compiler dies.  */
+  scoped_ignore_sigpipe ignore_sigpipe;
+
   /* Call the compiler and start the compilation process.  */
   compiler->set_source_file (fnames.source_file ());
   ok = compiler->compile (fnames.object_file (), compile_debug);
-- 
1.9.1