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[PATCH] Cygwin: ldd: Try harder to get dll names
- From: Mark Geisert <mark at maxrnd dot com>
- To: cygwin-patches at cygwin dot com
- Cc: Mark Geisert <mark at maxrnd dot com>
- Date: Wed, 14 Aug 2019 22:59:43 -0700
- Subject: [PATCH] Cygwin: ldd: Try harder to get dll names
Borrow a trick from strace to lessen occurrences of "??? => ???" in ldd
output. Specifically, if the module name isn't found in the usual place
in the mapped image, use the file handle we have to look up the name.
---
winsup/utils/Makefile.in | 2 +-
winsup/utils/ldd.cc | 44 +++++++++++++++++++++++++++++++++++++++-
2 files changed, 44 insertions(+), 2 deletions(-)
diff --git a/winsup/utils/Makefile.in b/winsup/utils/Makefile.in
index cebf39572..5bb62bc6f 100644
--- a/winsup/utils/Makefile.in
+++ b/winsup/utils/Makefile.in
@@ -101,7 +101,7 @@ cygpath.exe: CYGWIN_LDFLAGS += -lcygwin -luserenv -lntdll
ps.exe: CYGWIN_LDFLAGS += -lcygwin -lpsapi -lntdll
strace.exe: MINGW_LDFLAGS += -lntdll
-ldd.exe:CYGWIN_LDFLAGS += -lpsapi
+ldd.exe:CYGWIN_LDFLAGS += -lpsapi -lntdll
pldd.exe: CYGWIN_LDFLAGS += -lpsapi
minidumper.exe: CYGWIN_LDFLAGS += -ldbghelp
diff --git a/winsup/utils/ldd.cc b/winsup/utils/ldd.cc
index bbc62f12f..9bcc1df7f 100644
--- a/winsup/utils/ldd.cc
+++ b/winsup/utils/ldd.cc
@@ -39,6 +39,7 @@
#define _WIN32_WINNT 0x0a00
#include <windows.h>
+#include <winternl.h>
#include <imagehlp.h>
#include <psapi.h>
@@ -55,6 +56,7 @@ struct option longopts[] =
const char *opts = "dhruvV";
static int process_file (const wchar_t *);
+static void *drive_map;
static int
error (const char *fmt, ...)
@@ -152,6 +154,32 @@ get_module_filename (HANDLE hp, HMODULE hm)
return buf;
}
+static BOOL
+GetFileNameFromHandle(HANDLE hFile, WCHAR pszFilename[MAX_PATH+1])
+{
+ BOOL result = FALSE;
+ ULONG len = 0;
+ OBJECT_NAME_INFORMATION *ntfn = (OBJECT_NAME_INFORMATION *) alloca (65536);
+ NTSTATUS status = NtQueryObject (hFile, ObjectNameInformation,
+ ntfn, 65536, &len);
+ if (NT_SUCCESS (status))
+ {
+ PWCHAR win32path = ntfn->Name.Buffer;
+ win32path[ntfn->Name.Length / sizeof (WCHAR)] = L'\0';
+
+ /* NtQueryObject returns a native NT path. (Try to) convert to Win32. */
+ if (!drive_map)
+ drive_map = (void *) cygwin_internal (CW_ALLOC_DRIVE_MAP);
+ if (drive_map)
+ win32path = (PWCHAR) cygwin_internal (CW_MAP_DRIVE_MAP, drive_map,
+ win32path);
+ pszFilename[0] = L'\0';
+ wcsncat (pszFilename, win32path, MAX_PATH);
+ result = TRUE;
+ }
+ return result;
+}
+
static wchar_t *
load_dll (const wchar_t *fn)
{
@@ -215,6 +243,7 @@ start_process (const wchar_t *fn, bool& isdll)
struct dlls
{
LPVOID lpBaseOfDll;
+ HANDLE hFile;
struct dlls *next;
};
@@ -256,7 +285,17 @@ print_dlls (dlls *dll, const wchar_t *dllfn, const wchar_t *process_fn)
char *fn;
wchar_t *fullpath = get_module_filename (hProcess, (HMODULE) dll->lpBaseOfDll);
if (!fullpath)
- fn = strdup ("???");
+ {
+ // if no path found yet, try getting it from an open handle to the DLL
+ wchar_t dllname[MAX_PATH+1];
+ if (GetFileNameFromHandle (dll->hFile, dllname))
+ {
+ fn = tocyg (dllname);
+ saw_file (basename (fn));
+ }
+ else
+ fn = strdup ("???");
+ }
else if (dllfn && wcscmp (fullpath, dllfn) == 0)
{
free (fullpath);
@@ -340,6 +379,7 @@ report (const char *in_fn, bool multiple)
case LOAD_DLL_DEBUG_EVENT:
dll_last->next = (dlls *) malloc (sizeof (dlls));
dll_last->next->lpBaseOfDll = ev.u.LoadDll.lpBaseOfDll;
+ dll_last->next->hFile = ev.u.LoadDll.hFile;
dll_last->next->next = NULL;
dll_last = dll_last->next;
break;
@@ -423,6 +463,8 @@ main (int argc, char **argv)
while ((fn = *argv++))
if (report (fn, multiple))
ret = 1;
+ if (drive_map)
+ cygwin_internal (CW_FREE_DRIVE_MAP, drive_map);
exit (ret);
}
--
2.21.0