mingw: add a helper function to attach GDB to the current process
When debugging Git, the criss-cross spawning of processes can make things quite a bit difficult, especially when a Unix shell script is thrown in the mix that calls a `git.exe` that then segfaults. To help debugging such things, we introduce the `open_in_gdb()` function which can be called at a code location where the segfault happens (or as close as one can get); This will open a new MinTTY window with a GDB that already attached to the current process. Inspired by Derrick Stolee. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Johannes Schindelin committed
Feb 13, 2020 at 21:49 UTC
08809c09aa1351b603e9c55734105cd2e3c24c41
2 files changed
+23
compat/mingw.c
+13
@@ -13,6 +13,19 @@
13
14
static const int delay[] = { 0, 1, 10, 20, 40 };
15
16
+void open_in_gdb(void)
17
+{
18
+ static struct child_process cp = CHILD_PROCESS_INIT;
19
+ extern char *_pgmptr;
20
+
21
+ argv_array_pushl(&cp.args, "mintty", "gdb", NULL);
22
+ argv_array_pushf(&cp.args, "--pid=%d", getpid());
23
+ cp.clean_on_exit = 1;
24
+ if (start_command(&cp) < 0)
25
+ die_errno("Could not start gdb");
26
+ sleep(1);
27
+}
28
+
29
int err_win_to_posix(DWORD winerr)
30
{
31
int error = ENOSYS;
compat/mingw.h
+10
@@ -591,6 +591,16 @@ extern CRITICAL_SECTION pinfo_cs;
591
int wmain(int argc, const wchar_t **w_argv);
592
int main(int argc, const char **argv);
593
594
+/*
595
+ * For debugging: if a problem occurs, say, in a Git process that is spawned
596
+ * from another Git process which in turn is spawned from yet another Git
597
+ * process, it can be quite daunting to figure out what is going on.
598
+ *
599
+ * Call this function to open a new MinTTY (this assumes you are in Git for
600
+ * Windows' SDK) with a GDB that attaches to the current process right away.
601
+ */
602
+extern void open_in_gdb(void);
603
+
604
/*
605
* Used by Pthread API implementation for Windows
606
*/