Re: [PATCH 2/4] libbacktrace: detect executable path on windows

[Ian Lance Taylor <iant@golang.org>]

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On Tue, Jan 24, 2023 at 10:12 AM Eli Zaretskii via Gcc-patches
<gcc-patches@gcc.gnu.org> wrote:
>
> > From: Ian Lance Taylor <iant@golang.org>
> > Date: Tue, 24 Jan 2023 09:58:10 -0800
> > Cc: gcc@hazardy.de, gcc-patches@gcc.gnu.org, gcc@gcc.gnu.org
> >
> > I'd rather that the patch look like the appended.  Can someone with a
> > Windows system test to see what that builds and passes the tests?
>
> ENOPATCH

Gah.

Ian

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diff --git a/libbacktrace/config.h.in b/libbacktrace/config.h.in
index 94621c2e385..29d1ad3911a 100644
--- a/libbacktrace/config.h.in
+++ b/libbacktrace/config.h.in
@@ -100,6 +100,9 @@
 /* Define to 1 if you have the <unistd.h> header file. */
 #undef HAVE_UNISTD_H
 
+/* Define to 1 if you have the <windows.h> header file. */
+#undef HAVE_WINDOWS_H
+
 /* Define if -lz is available. */
 #undef HAVE_ZLIB
 
diff --git a/libbacktrace/configure b/libbacktrace/configure
index 6af2c04c81a..0a27cfb7799 100755
--- a/libbacktrace/configure
+++ b/libbacktrace/configure
@@ -13409,6 +13409,19 @@ $as_echo "#define HAVE_LOADQUERY 1" >>confdefs.h
 
 fi
 
+for ac_header in windows.h
+do :
+  ac_fn_c_check_header_mongrel "$LINENO" "windows.h" "ac_cv_header_windows_h" "$ac_includes_default"
+if test "x$ac_cv_header_windows_h" = xyes; then :
+  cat >>confdefs.h <<_ACEOF
+#define HAVE_WINDOWS_H 1
+_ACEOF
+
+fi
+
+done
+
+
 # Check for the fcntl function.
 if test -n "${with_target_subdir}"; then
    case "${host}" in
diff --git a/libbacktrace/configure.ac b/libbacktrace/configure.ac
index 39e6bf41e35..e3e10abd7b5 100644
--- a/libbacktrace/configure.ac
+++ b/libbacktrace/configure.ac
@@ -377,6 +377,8 @@ if test "$have_loadquery" = "yes"; then
   AC_DEFINE(HAVE_LOADQUERY, 1, [Define if AIX loadquery is available.])
 fi
 
+AC_CHECK_HEADERS(windows.h)
+
 # Check for the fcntl function.
 if test -n "${with_target_subdir}"; then
    case "${host}" in
diff --git a/libbacktrace/fileline.c b/libbacktrace/fileline.c
index 674bf33cdcf..e110b54ee24 100644
--- a/libbacktrace/fileline.c
+++ b/libbacktrace/fileline.c
@@ -47,6 +47,18 @@ POSSIBILITY OF SUCH DAMAGE.  */
 #include <mach-o/dyld.h>
 #endif
 
+#ifdef HAVE_WINDOWS_H
+#ifndef WIN32_MEAN_AND_LEAN
+#define WIN32_MEAN_AND_LEAN
+#endif
+
+#ifndef NOMINMAX
+#define NOMINMAX
+#endif
+
+#include <windows.h>
+#endif
+
 #include "backtrace.h"
 #include "internal.h"
 
@@ -155,6 +167,27 @@ macho_get_executable_path (struct backtrace_state *state,
 
 #endif /* !defined (HAVE_MACH_O_DYLD_H) */
 
+#ifdef HAVE_WINDOWS_H
+
+static char *
+windows_get_executable_path (char *buf, backtrace_error_callback error_callback,
+			     void *data)
+{
+  size_t got;
+
+  got = GetModuleFileNameA (NULL, buf, MAX_PATH - 1);
+  if (got == 0
+      || (got == MAX_PATH - 1 && GetLastError () == ERROR_INSUFFICIENT_BUFFER))
+    return NULL;
+  return buf;
+}
+
+#else /* !defined (HAVE_WINDOWS_H) */
+
+#define windows_get_executable_path(buf, error_callback, data) NULL
+
+#endif /* !defined (HAVE_WINDOWS_H) */
+
 /* Initialize the fileline information from the executable.  Returns 1
    on success, 0 on failure.  */
 
@@ -168,7 +201,11 @@ fileline_initialize (struct backtrace_state *state,
   int called_error_callback;
   int descriptor;
   const char *filename;
+#ifdef HAVE_WINDOWS_H
+  char buf[MAX_PATH];
+#else
   char buf[64];
+#endif
 
   if (!state->threaded)
     failed = state->fileline_initialization_failed;
@@ -192,7 +229,7 @@ fileline_initialize (struct backtrace_state *state,
 
   descriptor = -1;
   called_error_callback = 0;
-  for (pass = 0; pass < 8; ++pass)
+  for (pass = 0; pass < 9; ++pass)
     {
       int does_not_exist;
 
@@ -224,6 +261,9 @@ fileline_initialize (struct backtrace_state *state,
 	case 7:
 	  filename = macho_get_executable_path (state, error_callback, data);
 	  break;
+	case 8:
+	  filename = windows_get_executable_path (buf, error_callback, data);
+	  break;
 	default:
 	  abort ();
 	}