[PATCH] Check if /proc is usable on gdbserver start

[Vyacheslav Barinov <v.barinov@samsung.com>]

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Hello,

Just lost a couple of hours trying to find while gdb can't connect to gdbserver
in my debug session.

There's a buildroot where I want to debug a binary, and I tried to connect to
it from outside, but got very weird errors like architecture mismatch or
protocol errors. At last, after switching on '--debug' for gdbserver I found a
message 'Can't open /proc/pid/' message and suddenly found that I forgot to
mount procfs in my buildroot.

I think it's better to check this before running gdbserver.

Best Regards,
Slava Barinov.
    

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From 0d9bc48e145195b9ce04dedb3ca75ee93d90a32c Mon Sep 17 00:00:00 2001
From: Slava Barinov <v.barinov@samsung.com>
Date: Wed, 4 Jul 2018 10:20:42 +0300
Subject: [PATCH] Check if /proc is usable on gdbserver start

Add check if procfs is mount and can be accessed by gdbserver.

gdbserver/
	* linux-low.c (initialize_low): Add /proc check.

Signed-off-by: Slava Barinov <v.barinov@samsung.com>
---
 gdb/gdbserver/linux-low.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/gdb/gdbserver/linux-low.c b/gdb/gdbserver/linux-low.c
index 6e026f1aab..28273da1b9 100644
--- a/gdb/gdbserver/linux-low.c
+++ b/gdb/gdbserver/linux-low.c
@@ -7553,6 +7553,13 @@ void
 initialize_low (void)
 {
   struct sigaction sigchld_action;
+  struct stat st;
+
+  if (stat ("/proc/self", &st) != 0)
+    {
+      fprintf (stderr, "/proc is not accessible.\n");
+      exit (1);
+    }
 
   memset (&sigchld_action, 0, sizeof (sigchld_action));
   set_target_ops (&linux_target_ops);
-- 
2.18.0