testsuite: refactor spawn and wait for attach

Several places in the testsuite have a copy of a snippet of code that
spawns a test program, waits a bit, and then does some PID munging for
Cygwin.  This is in order to have GDB attach to the spawned program.

This refactors all that to a common procedure.

(multi-attach.exp wants to spawn multiple processes, so this makes the
new procedure's interface work with lists.)

Tested on x86_64 Fedora 20.

gdb/testsuite/ChangeLog:
2014-09-11  Pedro Alves  <palves@redhat.com>

	* lib/gdb.exp (spawn_wait_for_attach): New procedure.
	* gdb.base/attach.exp (do_attach_tests, do_call_attach_tests)
	(do_command_attach_tests): Use spawn_wait_for_attach.
	* gdb.base/solib-overlap.exp: Likewise.
	* gdb.multi/multi-attach.exp: Likewise.
	* gdb.python/py-prompt.exp: Likewise.
	* gdb.python/py-sync-interp.exp: Likewise.
	* gdb.server/ext-attach.exp: Likewise.

1 files changed, 25 insertions, 0 deletions

diff --git a/gdb/testsuite/lib/gdb.exp b/gdb/testsuite/lib/gdb.exp
index 82242f4..274cad2 100644
--- a/gdb/testsuite/lib/gdb.exp
+++ b/gdb/testsuite/lib/gdb.exp
@@ -3324,6 +3324,31 @@ proc gdb_exit { } {
     catch default_gdb_exit
 }
 
+# Start a set of programs running and then wait for a bit, to be sure
+# that they can be attached to.  Return a list of the processes' PIDs.
+
+proc spawn_wait_for_attach { executable_list } {
+    set pid_list {}
+
+    foreach {executable} $executable_list {
+	lappend pid_list [eval exec $executable &]
+    }
+
+    sleep 2
+
+    if { [istarget "*-*-cygwin*"] } {
+	for {set i 0} {$i < [llength $pid_list]} {incr i} {
+	    # testpid is the Cygwin PID, GDB uses the Windows PID,
+	    # which might be different due to the way fork/exec works.
+	    set testpid [lindex $pid_list $i]
+	    set testpid [ exec ps -e | gawk "{ if (\$1 == $testpid) print \$4; }" ]
+	    set pid_list [lreplace $pid_list $i $i $testpid]
+	}
+    }
+
+    return $pid_list
+}
+
 #
 # gdb_load_cmd -- load a file into the debugger.
 #		  ARGS - additional args to load command.