From 6f64ef53c0a77b34717741d4a5453760ff2a2cab Mon Sep 17 00:00:00 2001 From: Pedro Alves Date: Fri, 26 Jul 2013 11:15:45 +0000 Subject: GDB kills itself instead of interrupting inferior When GDB is run with IO redirected to a pipe, the 'interrupt' command causes it to kill its own process group instead of the inferior's. The problem manifests itself in async mode, native debugging: $ cat | gdb (gdb) set target-async on (gdb) run & (gdb) interrupt A debugging session is active. Inferior 1 [process 20584] will be killed. Quit anyway? (y or n) [answered Y; input not from terminal] In this case, GDB tells that its stdin isn't a tty and doesn't save the inferior's process group in inflow.c:terminal_init_inferior_with_pgrp. The 'interrupt' command tries to 'kill' the inferior's process group in `inf-ptrace.c:inf_ptrace_stop`, but since that wasn't saved in the first place, GDB kills process group 0, meaning, its own process group. When GDB is used from a frontend, that means killing its own process group including the frontend and possibly the X session. This was originally seen with SublimeGDB: https://github.com/quarnster/SublimeGDB/issues/29. The patch makes GDB save the inferior pgid regardless of having a terminal, as pgid is used not only to reset foreground process group, but also to interrupt the inferior process. It also adds a regression test. Luckily, we can emulate not having a terminal with "set interactive-mode off", avoiding the need of special magic to spawn gdb with a pipe. Tested on x86_64 Fedora 17. gdb/ 2013-07-26 Cyril Nikolaev * inflow.c (terminal_init_inferior_with_pgrp): Save inferior process group regardless of having tty on stdin. gdb/testsuite/ 2013-07-26 Pedro Alves * gdb.base/interrupt-noterm.c, gdb.base/interrupt-noterm.exp: New files. --- gdb/inflow.c | 17 ++++++++++------- 1 file changed, 10 insertions(+), 7 deletions(-) (limited to 'gdb/inflow.c') diff --git a/gdb/inflow.c b/gdb/inflow.c index 79a99d1..faf4888 100644 --- a/gdb/inflow.c +++ b/gdb/inflow.c @@ -217,19 +217,22 @@ static void terminal_ours_1 (int); void terminal_init_inferior_with_pgrp (int pgrp) { + struct inferior *inf = current_inferior (); + struct terminal_info *tinfo = get_inflow_inferior_data (inf); + +#ifdef PROCESS_GROUP_TYPE + /* Store the process group even without a terminal as it is used not + only to reset the tty foreground process group, but also to + interrupt the inferior. */ + tinfo->process_group = pgrp; +#endif + if (gdb_has_a_terminal ()) { - struct inferior *inf = current_inferior (); - struct terminal_info *tinfo = get_inflow_inferior_data (inf); - xfree (tinfo->ttystate); tinfo->ttystate = serial_copy_tty_state (stdin_serial, our_terminal_info.ttystate); -#ifdef PROCESS_GROUP_TYPE - tinfo->process_group = pgrp; -#endif - /* Make sure that next time we call terminal_inferior (which will be before the program runs, as it needs to be), we install the new process group. */ -- cgit v1.1