[PATCH 1/3] [gdbserver/win32] fatal "glob could not process pattern '(null)'" error

[Joel Brobecker <brobecker@adacore.com>]

Trying to start GDBserver on Windows currently yields the following
error...

    $ gdbserver.exe --once :4444 simple_main.exe
    glob could not process pattern '(null)'.
    Exiting

... after which GDB terminates with a nonzero status.

This is because create_process in win32-low.c calls gdb_tilde_expand
with the result of a call to get_inferior_cwd without verifying that
the returned directory is not NULL:

    | static BOOL
    | create_process (const char *program, char *args,
    |                 DWORD flags, PROCESS_INFORMATION *pi)
    | {
    |   const char *inferior_cwd = get_inferior_cwd ();
    |   std::string expanded_infcwd = gdb_tilde_expand (inferior_cwd);

This patch avoids this by only calling gdb_tilde_expand when
INFERIOR_CWD is not NULL, which is similar to what is done on
GNU/Linux for instance.

gdb/gdbserver/ChangeLog:

	* win32-low.c (create_process): Only call gdb_tilde_expand if
	inferior_cwd is not NULL.
---
 gdb/gdbserver/win32-low.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/gdb/gdbserver/win32-low.c b/gdb/gdbserver/win32-low.c
index 9f0c4e4..db5dd49 100644
--- a/gdb/gdbserver/win32-low.c
+++ b/gdb/gdbserver/win32-low.c
@@ -556,7 +556,6 @@ create_process (const char *program, char *args,
 		DWORD flags, PROCESS_INFORMATION *pi)
 {
   const char *inferior_cwd = get_inferior_cwd ();
-  std::string expanded_infcwd = gdb_tilde_expand (inferior_cwd);
   BOOL ret;
 
 #ifdef _WIN32_WCE
@@ -576,6 +575,7 @@ create_process (const char *program, char *args,
 
   if (inferior_cwd != NULL)
     {
+      std::string expanded_infcwd = gdb_tilde_expand (inferior_cwd);
       std::replace (expanded_infcwd.begin (), expanded_infcwd.end (),
 		    '/', '\\');
       wcwd = alloca ((expanded_infcwd.size () + 1) * sizeof (wchar_t));
@@ -607,7 +607,10 @@ Could not convert the expanded inferior cwd to wide-char."));
 			TRUE,     /* inherit handles */
 			flags,    /* start flags */
 			NULL,     /* environment */
-			expanded_infcwd.c_str (), /* current directory */
+			/* current directory */
+			(inferior_cwd == NULL
+			 ? NULL
+			 : gdb_tilde_expand (inferior_cwd).c_str()),
 			&si,      /* start info */
 			pi);      /* proc info */
 #endif
-- 
2.1.4