From 97ad458125294fc16d151177c5278ea3288dfbce Mon Sep 17 00:00:00 2001 From: Joel Brobecker Date: Tue, 1 Oct 2013 10:56:51 +0000 Subject: [PATCH] [gdbserver/LynxOS]: Incomplete thread list after --attach The current implementation is forgetting to populate the thread list when attaching to the process. This results in an incomplete list of threads when debugging a threaded program. Unfortunately, as the added comments hints, there appears to be no way of getting the list of threads via ptrace, other than by spawning the "ps" command, and parsing its output. Not great, but it appears to be the best we can do. gdb/gdbserver/ChangeLog: * lynx-low.c (lynx_add_threads_after_attach): New function. (lynx_attach): Remove call to add_thread. Add call to lynx_add_threads_after_attach instead. --- gdb/gdbserver/ChangeLog | 6 ++++++ gdb/gdbserver/lynx-low.c | 38 +++++++++++++++++++++++++++++++++++++- 2 files changed, 43 insertions(+), 1 deletion(-) diff --git a/gdb/gdbserver/ChangeLog b/gdb/gdbserver/ChangeLog index 460d9a1205..469a2df1a4 100644 --- a/gdb/gdbserver/ChangeLog +++ b/gdb/gdbserver/ChangeLog @@ -1,3 +1,9 @@ +2013-10-01 Joel Brobecker + + * lynx-low.c (lynx_add_threads_after_attach): New function. + (lynx_attach): Remove call to add_thread. Add call to + lynx_add_threads_after_attach instead. + 2013-09-28 Mike Frysinger * configure.ac (AC_CHECK_HEADERS): Add sys/syscall.h diff --git a/gdb/gdbserver/lynx-low.c b/gdb/gdbserver/lynx-low.c index 3c75b6296b..3c061b8f07 100644 --- a/gdb/gdbserver/lynx-low.c +++ b/gdb/gdbserver/lynx-low.c @@ -262,6 +262,42 @@ lynx_create_inferior (char *program, char **allargs) return pid; } +/* Assuming we've just attached to a running inferior whose pid is PID, + add all threads running in that process. */ + +static void +lynx_add_threads_after_attach (int pid) +{ + /* Ugh! There appears to be no way to get the list of threads + in the program we just attached to. So get the list by calling + the "ps" command. This is only needed now, as we will then + keep the thread list up to date thanks to thread creation and + exit notifications. */ + FILE *f; + char buf[256]; + int thread_pid, thread_tid; + + f = popen ("ps atx", "r"); + if (f == NULL) + perror_with_name ("Cannot get thread list"); + + while (fgets (buf, sizeof (buf), f) != NULL) + if ((sscanf (buf, "%d %d", &thread_pid, &thread_tid) == 2 + && thread_pid == pid)) + { + ptid_t thread_ptid = lynx_ptid_build (pid, thread_tid); + + if (!find_thread_ptid (thread_ptid)) + { + lynx_debug ("New thread: (pid = %d, tid = %d)", + pid, thread_tid); + add_thread (thread_ptid, NULL); + } + } + + pclose (f); +} + /* Implement the attach target_ops method. */ static int @@ -274,7 +310,7 @@ lynx_attach (unsigned long pid) strerror (errno), errno); lynx_add_process (pid, 1); - add_thread (ptid, NULL); + lynx_add_threads_after_attach (pid); return 0; }