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

[Björn Schäpers]

From: Björn Schäpers <bjo...@hazardy.de>

This is actually needed so that libstdc++'s <stacktrace> implementation
to be able to work on windows.

Tested on x86_64-linux and i686-w64-mingw32.

-- >8 --

        * configure.ac: Add a check for windows.h.
        * configure, config.h.in: Regenerate.
        * fileline.c: Add windows_get_executable_path.
        * fileline.c (fileline_initialiez): Add a pass using
        windows_get_executable_path.

Signed-off-by: Björn Schäpers <bjo...@hazardy.de>
---
 libbacktrace/configure.ac |  2 ++
 libbacktrace/fileline.c   | 43 ++++++++++++++++++++++++++++++++++++++-
 4 files changed, 60 insertions(+), 1 deletion(-)

diff --git a/libbacktrace/configure.ac b/libbacktrace/configure.ac
index 1daaa2f62d2..b5feb29bcdc 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 a40cd498114..73c2c8e8bc9 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 +167,28 @@ 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)
+{
+  if (GetModuleFileNameA (NULL, buf, MAX_PATH - 1) == 0)
+    {
+      error_callback (data,
+                     "could not get the filename of the current executable",
+                     (int) GetLastError ());
+      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 +202,11 @@ 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 +230,7 @@ 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 +262,9 @@ 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 ();
        }
-- 
2.38.1