[committed] : [PATCH 0/4] PR14161: a partial fix

Yao Qi
2012-07-27T08:19:51Z

On Saturday, June 09, 2012 08:46:38 PM Yao Qi wrote:
> Hi,
> PR14161 reports that agent socket '/tmp/gdb_ustXXXX' is not removed when
> program is done. This patch series is to address this problem partially
> only in GDBserver side (in patch 3/4) and kfail it temporarily in GDB
> side (in patch 4/4) due to some limitations on threads control.
> Patch 1/4 is a new test case to show this problem.

This is what I applied to HEAD.

--
Yao (齐尧)

gdb/gdbserver/
PR remote/14161.

* server.h: Declare gdb_agent_about_to_close.
* target.c (kill_inferior): Include "agent.h".
New. Send command 'kill'.
* target.h (kill_inferior): Removed macro.
* tracepoint.c (gdb_agent_about_to_close): New.
(gdb_agent_helper_thread): Handle command 'close'.
Wait endlessly until the inferior stops.
Install gdb_agent_remove_socket to atexit hook.
(agent_socket_name): New static variable.
(gdb_agent_socket_init): Replace local variable 'name' with
'agent_socket_name'.
(gdb_agent_remove_socket): New.

gdb/doc/
* gdb.texinfo (IPA Protocol Commands): Document new command
'close'.

gdb/testsuite/
KFAIL for PR remote/14161.
* gdb.trace/strace.exp (strace_remove_socket): kfail for native.
Cleanup socket files.
(strace_info_marker): Detach inferior.

diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index facca8f..a4503bf 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -33673,6 +33673,10 @@ for an error

@end table

+@item close
+Closes the in-process agent. This command is sent when @value{GDBN} or GDBserver
+is about to kill inferiors.
+
@item qTfSTM
@xref{qTfSTM}.
@item qTsSTM
diff --git a/gdb/gdbserver/server.h b/gdb/gdbserver/server.h
index 02dfa29..752bc3b 100644
--- a/gdb/gdbserver/server.h
+++ b/gdb/gdbserver/server.h
@@ -467,6 +467,7 @@ void stop_tracing (void);

int claim_trampoline_space (ULONGEST used, CORE_ADDR *trampoline);
int have_fast_tracepoint_trampoline_buffer (char *msgbuf);
+void gdb_agent_about_to_close (int pid);
#endif

struct traceframe;
diff --git a/gdb/gdbserver/target.c b/gdb/gdbserver/target.c
index 7539476..e8b2b08 100644
--- a/gdb/gdbserver/target.c
+++ b/gdb/gdbserver/target.c
@@ -182,3 +182,11 @@ target_waitstatus_to_string (const struct target_waitstatus *ws)

return buf;
}
+
+int
+kill_inferior (int pid)
+{
+ gdb_agent_about_to_close (pid);
+
+ return (*the_target->kill) (pid);
+}
diff --git a/gdb/gdbserver/target.h b/gdb/gdbserver/target.h
index 0cf5687..9f96e04 100644
--- a/gdb/gdbserver/target.h
+++ b/gdb/gdbserver/target.h
@@ -409,8 +409,7 @@ void set_target_ops (struct target_ops *);
#define myattach(pid) \
(*the_target->attach) (pid)

-#define kill_inferior(pid) \
- (*the_target->kill) (pid)
+int kill_inferior (int);

#define detach_inferior(pid) \
(*the_target->detach) (pid)
diff --git a/gdb/gdbserver/tracepoint.c b/gdb/gdbserver/tracepoint.c
index f103dfc..7ad77f0 100644
--- a/gdb/gdbserver/tracepoint.c
+++ b/gdb/gdbserver/tracepoint.c
@@ -3923,6 +3923,38 @@ cmd_qtstmat (char *packet)
run_inferior_command (packet, strlen (packet) + 1);
}

+/* Sent the agent a command to close it. */
+
+void
+gdb_agent_about_to_close (int pid)
+{
+ char buf[IPA_CMD_BUF_SIZE];
+
+ if (!maybe_write_ipa_not_loaded (buf))
+ {
+ struct thread_info *save_inferior;
+ struct inferior_list_entry *inf = all_threads.head;
+
+ save_inferior = current_inferior;
+
+ /* Find a certain thread which belongs to process PID. */
+ while (inf != NULL)
+ {
+ if (ptid_get_pid (inf->id) == pid)
+ break;
+ inf = inf->next;
+ }
+
+ current_inferior = (struct thread_info *) inf;
+
+ strcpy (buf, "close");
+
+ run_inferior_command (buf, strlen (buf) + 1);
+
+ current_inferior = save_inferior;
+ }
+}
+
/* Return the minimum instruction size needed for fast tracepoints as a
hexadecimal number. */

@@ -6748,13 +6780,14 @@ init_named_socket (const char *name)
return fd;
}

+static char agent_socket_name[UNIX_PATH_MAX];
+
static int
gdb_agent_socket_init (void)
{
int result, fd;
- char name[UNIX_PATH_MAX];

- result = xsnprintf (name, UNIX_PATH_MAX, "%s/gdb_ust%d",
+ result = xsnprintf (agent_socket_name, UNIX_PATH_MAX, "%s/gdb_ust%d",
SOCK_DIR, getpid ());
if (result >= UNIX_PATH_MAX)
{
@@ -6762,11 +6795,11 @@ gdb_agent_socket_init (void)
return -1;
}

- fd = init_named_socket (name);
+ fd = init_named_socket (agent_socket_name);
if (fd < 0)
warning ("Error initializing named socket (%s) for communication with the "
"ust helper thread. Check that directory exists and that it "
- "is writable.", name);
+ "is writable.", agent_socket_name);

return fd;
}
@@ -6995,6 +7028,13 @@ gdb_ust_init (void)
#endif /* HAVE_UST */

#include <sys/syscall.h>
+#include <stdlib.h>
+
+static void
+gdb_agent_remove_socket (void)
+{
+ unlink (agent_socket_name);
+}

/* Helper thread of agent. */

@@ -7003,6 +7043,8 @@ gdb_agent_helper_thread (void *arg)
{
int listen_fd;

+ atexit (gdb_agent_remove_socket);
+
while (1)
{
listen_fd = gdb_agent_socket_init ();
@@ -7023,6 +7065,7 @@ gdb_agent_helper_thread (void *arg)
int fd;
char buf[1];
int ret;
+ int stop_loop = 0;

tmp = sizeof (sockaddr);

@@ -7055,8 +7098,12 @@ gdb_agent_helper_thread (void *arg)

if (cmd_buf[0])
{
+ if (strncmp ("close", cmd_buf, 5) == 0)
+ {
+ stop_loop = 1;
+ }
#ifdef HAVE_UST
- if (strcmp ("qTfSTM", cmd_buf) == 0)
+ else if (strcmp ("qTfSTM", cmd_buf) == 0)
{
cmd_qtfstm (cmd_buf);
}
@@ -7088,6 +7135,20 @@ gdb_agent_helper_thread (void *arg)
/* Fix compiler's warning: ignoring return value of 'write'. */
ret = write (fd, buf, 1);
close (fd);
+
+ if (stop_loop)
+ {
+ close (listen_fd);
+ unlink (agent_socket_name);
+
+ /* Sleep endlessly to wait the whole inferior stops. This
+ thread can not exit because GDB or GDBserver may still need
+ 'current_inferior' (representing this thread) to access
+ inferior memory. Otherwise, this thread exits earlier than
+ other threads, and 'current_inferior' is set to NULL. */
+ while (1)
+ sleep (10);
+ }
}
}

diff --git a/gdb/testsuite/gdb.trace/strace.exp b/gdb/testsuite/gdb.trace/strace.exp
index d9e90b6..f09eeb3 100644
--- a/gdb/testsuite/gdb.trace/strace.exp
+++ b/gdb/testsuite/gdb.trace/strace.exp
@@ -37,12 +37,103 @@ if { [gdb_compile $srcdir/$subdir/$srcfile $binfile executable $additional_flags
return -1
}

+# Test that the socket file is removed when GDB quits, detaches or
+# resumes the inferior until it exits.
+
+proc strace_remove_socket { action } {
+ with_test_prefix "remove_socket_after_${action}" {
+
+ global executable
+ global gdb_prompt
+ global libipa
+
+ # Restart with a fresh gdb.
+ clean_restart $executable
+ gdb_load_shlibs $libipa
+ if ![runto_main] {
+ fail "Can't run to main"
+ return -1
+ }
+
+ # List the markers in program.
+ gdb_test "info static-tracepoint-markers" \
+ ".*ust/bar\[\t \]+n\[\t \]+.*ust/bar2\[\t \]+n\[\t \]+.*"
+
+ set pid ""
+ set test "collect pid"
+ gdb_test_multiple "info inferiors" $test {
+ -re "process (\[-0-9a-fx\]+) \[^\n\]*\n.*${gdb_prompt} $" {
+ set pid $expect_out(1,string)
+ pass $test
+ }
+ -re ".*${gdb_prompt} $" {
+ fail $test
+ }
+ }
+
+ set test "socket file exists"
+ set socket_file "/tmp/gdb_ust${pid}"
+ set status [remote_exec target "sh -c { \[ -S $socket_file \] }"]
+
+ if { [lindex $status 0] == 0 } {
+ pass $test
+ } else {
+ fail $test
+ }
+
+ send_gdb "${action}\n"
+ gdb_expect {
+ -re "A debugging session is active.\r\n.*\r\nQuit anyway\\? \\(y or n\\) $" {
+ send_gdb "y\n"
+ }
+ -re "Detaching .*, process .*$" {
+ }
+ -re "Continuing.*$" {
+ }
+ }
+
+ set exists 1
+
+ for {set i 1} {$i <= 5} {incr i} {
+ set status [remote_exec target "sh -c { \[ -S $socket_file \] }"]
+ if { [lindex $status 0] != 0 } {
+ set exists 0
+ break
+ }
+ sleep 1
+ }
+
+ if { ![is_remote target] && ![string equal $action "detach"] } {
+ setup_kfail gdb/14161 *-*-*
+ }
+
+ set test "socket file removed"
+
+ if { $exists } {
+ fail $test
+ # Since $socket_file is a socket file instead of a regular file, we
+ # can't use 'remote_file target delete $socket_file' here.
+ remote_exec target "sh -c \"rm -r $socket_file\""
+ } else {
+ pass $test
+ }
+
+ if { [string equal $action "quit"] && [is_remote host] } {
+ global gdb_spawn_id
+ # unset gdb_spawn_id here to avoid sending command 'quit' to GDB
+ # later in default_gdb_exit.
+ unset gdb_spawn_id
+ }
+}}
+
proc strace_info_marker { } { with_test_prefix "info_marker" {
global executable
global gdb_prompt
+ global libipa

# Restart with a fresh gdb.
clean_restart $executable
+ gdb_load_shlibs $libipa
if ![runto_main] {
fail "Can't run to main"
return -1
@@ -59,6 +150,13 @@ proc strace_info_marker { } { with_test_prefix "info_marker" {
pass "info threads"
}
}
+
+ # GDB detaches inferior so that the socket file can be removed.
+ gdb_test_multiple "detach" "detach" {
+ -re "Detaching .*, process .*${gdb_prompt} $" {
+ pass "detach"
+ }
+ }
}}

proc strace_probe_marker { } { with_test_prefix "probe_marker" {
@@ -66,9 +164,11 @@ proc strace_probe_marker { } { with_test_prefix "probe_marker" {
global expect_out
global gdb_prompt
global hex
+ global libipa

# Restart with a fresh gdb.
clean_restart $executable
+ gdb_load_shlibs $libipa
if ![runto_main] {
fail "Can't run to main"
return -1
@@ -97,9 +197,11 @@ with_test_prefix "trace_same_addr $type" {
global expect_out
global gdb_prompt
global hex
+ global libipa

# Restart with a fresh gdb.
clean_restart $executable
+ gdb_load_shlibs $libipa
if ![runto_main] {
fail "Can't run to main"
return -1
@@ -192,9 +294,11 @@ proc strace_trace_on_diff_addr { } { with_test_prefix "trace_diff_addr" {
global expect_out
global gdb_prompt
global hex
+ global libipa

# Restart with a fresh gdb.
clean_restart $executable
+ gdb_load_shlibs $libipa
if ![runto_main] {
fail "Can't run to main"
return -1
@@ -240,28 +344,30 @@ proc strace_trace_on_diff_addr { } { with_test_prefix "trace_diff_addr" {
gdb_test "tfind" "Target failed to find requested trace frame\\..*"
}}

-clean_restart $executable
+# Run it on x86/x86_64 linux.
+if { [istarget "x86_64-*-linux*"] || [istarget "i\[34567\]86-*-linux*"] } {
+ strace_info_marker
+ strace_remove_socket "quit"
+ strace_remove_socket "detach"
+ strace_remove_socket "continue"
+}

+clean_restart $executable
+gdb_load_shlibs $libipa
if ![runto_main] {
fail "Can't run to main to check for trace support"
return -1
}
-
-# Run it on native x86/x86_64 linux.
-if { ![is_remote target]
- && ([istarget "x86_64-*-linux*"] || [istarget "i\[34567\]86-*-linux*"]) } {
- strace_info_marker
- return
-}
-
if { ![gdb_target_supports_trace] } then {
+ # At this point, the socket file has been created. We must make sure it is
+ # removed when we return here. GDB detaches inferior so that the socket
+ # file can be removed. Note that GDB simply kill inferior doesn't remove
+ # the socket file.
+ gdb_test "detach" "Detaching .*, process .*"
unsupported "Current target does not support trace"
return -1;
}

-gdb_load_shlibs $libipa
-
-strace_info_marker
strace_probe_marker

strace_trace_on_same_addr "trace"