[binutils-gdb] testsuite: Fix a `server_pid' access crash in gdb.server/server-kill.exp

[Maciej W.Rozycki <macro at sourceware dot org>]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=0726fcc61a8b7c943de513ec598b2189c5f67715

commit 0726fcc61a8b7c943de513ec598b2189c5f67715
Author: Maciej W. Rozycki <macro@mips.com>
Date:   Tue May 15 15:54:36 2018 +0100

    testsuite: Fix a `server_pid' access crash in gdb.server/server-kill.exp
    
    Fix a commit f90183d7e31b ("Get GDBserver pid on remote target") bug and
    correctly handle the case where the PID of `gdbserver' could not have
    been retrieved.  If that happens, $server_pid is unset causing:
    
    FAIL: gdb.server/server-kill.exp: p server_pid
    ERROR: tcl error sourcing .../gdb/testsuite/gdb.server/server-kill.exp.
    ERROR: can't read "server_pid": no such variable
        while executing
    "if {$server_pid == "" } {
        return -1
    }"
        (file ".../gdb/testsuite/gdb.server/server-kill.exp" line 49)
        invoked from within
    "source .../gdb/testsuite/gdb.server/server-kill.exp"
        ("uplevel" body line 1)
        invoked from within
    "uplevel #0 source .../gdb/testsuite/gdb.server/server-kill.exp"
        invoked from within
    "catch "uplevel #0 source $test_file_name""
    
    Verify that the variable exists then rather than trying to access it.
    
    	gdb/testsuite/
    	* gdb.server/server-kill.exp: Verify whether `server_pid' exists
    	rather then trying to access it in determining whether the PID
    	of `gdbserver' could have been retrieved.

Diff:
---
 gdb/testsuite/ChangeLog                  | 6 ++++++
 gdb/testsuite/gdb.server/server-kill.exp | 2 +-
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog
index 9fc54c0..b18d4b6 100644
--- a/gdb/testsuite/ChangeLog
+++ b/gdb/testsuite/ChangeLog
@@ -1,3 +1,9 @@
+2018-05-15  Maciej W. Rozycki  <macro@mips.com>
+
+	* gdb.server/server-kill.exp: Verify whether `server_pid' exists
+	rather then trying to access it in determining whether the PID
+	of `gdbserver' could have been retrieved.
+
 2018-05-08  Andrew Burgess  <andrew.burgess@embecosm.com>
 
 	* gdb.arch/amd64-init-x87-values.S: New file.
diff --git a/gdb/testsuite/gdb.server/server-kill.exp b/gdb/testsuite/gdb.server/server-kill.exp
index 0701d5f..c110f3a 100644
--- a/gdb/testsuite/gdb.server/server-kill.exp
+++ b/gdb/testsuite/gdb.server/server-kill.exp
@@ -46,7 +46,7 @@ gdb_test_multiple $test $test {
     }
 }
 
-if {$server_pid == "" } {
+if ![info exists server_pid] {
     return -1
 }