Andrew Nguyen : kernel32: Correct output buffer behavior with empty input strings for FormatMessageA /W.
Alexandre Julliard
julliard at winehq.org
Wed Apr 28 16:35:47 CDT 2010
Module: wine
Branch: master
Commit: 2193b9e887b109a7134d3318406be665a45471af
URL: http://source.winehq.org/git/wine.git/?a=commit;h=2193b9e887b109a7134d3318406be665a45471af
Author: Andrew Nguyen <anguyen at codeweavers.com>
Date: Wed Apr 28 04:20:32 2010 -0500
kernel32: Correct output buffer behavior with empty input strings for FormatMessageA/W.
---
dlls/kernel32/format_msg.c | 48 +++++++++++++++++--------
dlls/kernel32/tests/format_msg.c | 71 ++++++++++++++++++++++++++++++++++++-
2 files changed, 101 insertions(+), 18 deletions(-)
diff --git a/dlls/kernel32/format_msg.c b/dlls/kernel32/format_msg.c
index feed8a1..185c459 100644
--- a/dlls/kernel32/format_msg.c
+++ b/dlls/kernel32/format_msg.c
@@ -446,22 +446,30 @@ DWORD WINAPI FormatMessageA(
goto failure;
TRACE("-- %s\n", debugstr_w(target));
- destlength = WideCharToMultiByte(CP_ACP, 0, target, -1, NULL, 0, NULL, NULL);
- if (dwFlags & FORMAT_MESSAGE_ALLOCATE_BUFFER) {
- LPSTR buf = LocalAlloc(LMEM_ZEROINIT, max(nSize, destlength));
- WideCharToMultiByte(CP_ACP, 0, target, -1, buf, destlength, NULL, NULL);
- *((LPSTR*)lpBuffer) = buf;
- } else {
- if (nSize < destlength)
+
+ /* Only try writing to an output buffer if there are processed characters
+ * in the temporary output buffer. */
+ if (*target)
+ {
+ destlength = WideCharToMultiByte(CP_ACP, 0, target, -1, NULL, 0, NULL, NULL);
+ if (dwFlags & FORMAT_MESSAGE_ALLOCATE_BUFFER)
{
- SetLastError(ERROR_INSUFFICIENT_BUFFER);
- goto failure;
+ LPSTR buf = LocalAlloc(LMEM_ZEROINIT, max(nSize, destlength));
+ WideCharToMultiByte(CP_ACP, 0, target, -1, buf, destlength, NULL, NULL);
+ *((LPSTR*)lpBuffer) = buf;
}
-
- WideCharToMultiByte(CP_ACP, 0, target, -1, lpBuffer, destlength, NULL, NULL);
+ else
+ {
+ if (nSize < destlength)
+ {
+ SetLastError(ERROR_INSUFFICIENT_BUFFER);
+ goto failure;
+ }
+ WideCharToMultiByte(CP_ACP, 0, target, -1, lpBuffer, destlength, NULL, NULL);
+ }
+ ret = destlength - 1; /* null terminator */
}
- ret = destlength - 1; /* null terminator */
failure:
HeapFree(GetProcessHeap(),0,target);
HeapFree(GetProcessHeap(),0,from);
@@ -542,10 +550,18 @@ DWORD WINAPI FormatMessageW(
talloced = strlenW(target)+1;
TRACE("-- %s\n",debugstr_w(target));
- if (dwFlags & FORMAT_MESSAGE_ALLOCATE_BUFFER) {
- /* nSize is the MINIMUM size */
- *((LPVOID*)lpBuffer) = LocalAlloc(LMEM_ZEROINIT, max(nSize, talloced)*sizeof(WCHAR));
- strcpyW(*(LPWSTR*)lpBuffer, target);
+
+ /* Only allocate a buffer if there are processed characters in the
+ * temporary output buffer. If a caller supplies the buffer, then
+ * a null terminator will be written to it. */
+ if (dwFlags & FORMAT_MESSAGE_ALLOCATE_BUFFER)
+ {
+ if (*target)
+ {
+ /* nSize is the MINIMUM size */
+ *((LPVOID*)lpBuffer) = LocalAlloc(LMEM_ZEROINIT, max(nSize, talloced)*sizeof(WCHAR));
+ strcpyW(*(LPWSTR*)lpBuffer, target);
+ }
}
else
{
diff --git a/dlls/kernel32/tests/format_msg.c b/dlls/kernel32/tests/format_msg.c
index e1f5b3e..9021c09 100644
--- a/dlls/kernel32/tests/format_msg.c
+++ b/dlls/kernel32/tests/format_msg.c
@@ -53,6 +53,7 @@ static DWORD __cdecl doitW(DWORD flags, LPCVOID src, DWORD msg_id, DWORD lang_id
static void test_message_from_string_wide(void)
{
static const WCHAR test[] = {'t','e','s','t',0};
+ static const WCHAR empty[] = {0};
static const WCHAR te[] = {'t','e',0};
static const WCHAR st[] = {'s','t',0};
static const WCHAR t[] = {'t',0};
@@ -144,6 +145,25 @@ static void test_message_from_string_wide(void)
ok(!lstrcmpW(test, out), "failed out=%s\n", wine_dbgstr_w(out));
ok(r==4, "failed: r=%d\n", r);
+ /* null string, crashes on Windows */
+ if (0)
+ {
+ SetLastError(0xdeadbeef);
+ memcpy(out, init_buf, sizeof(init_buf));
+ r = FormatMessageW(FORMAT_MESSAGE_FROM_STRING, NULL, 0,
+ 0, out, sizeof(out)/sizeof(WCHAR), NULL);
+ }
+
+ /* empty string */
+ SetLastError(0xdeadbeef);
+ memcpy(out, init_buf, sizeof(init_buf));
+ r = FormatMessageW(FORMAT_MESSAGE_FROM_STRING, empty, 0,
+ 0, out, sizeof(out)/sizeof(WCHAR), NULL);
+ error = GetLastError();
+ ok(!lstrcmpW(empty, out), "failed out=%s\n", wine_dbgstr_w(out));
+ ok(r==0, "succeeded: r=%d\n", r);
+ ok(error==0xdeadbeef, "last error %u\n", error);
+
/* format placeholder with no specifier */
SetLastError(0xdeadbeef);
memcpy(out, init_buf, sizeof(init_buf));
@@ -420,6 +440,27 @@ static void test_message_from_string(void)
ok(!strcmp("test", out),"failed out=[%s]\n",out);
ok(r==4,"failed: r=%d\n",r);
+ /* null string, crashes on Windows */
+ if (0)
+ {
+ SetLastError(0xdeadbeef);
+ memcpy(out, init_buf, sizeof(init_buf));
+ r = FormatMessageA(FORMAT_MESSAGE_FROM_STRING, NULL, 0,
+ 0, out, sizeof(out)/sizeof(CHAR), NULL);
+ }
+
+ /* empty string */
+ SetLastError(0xdeadbeef);
+ memcpy(out, init_buf, sizeof(init_buf));
+ r = FormatMessageA(FORMAT_MESSAGE_FROM_STRING, "", 0,
+ 0, out, sizeof(out)/sizeof(CHAR), NULL);
+ ok(!memcmp(out, init_buf, sizeof(init_buf)) ||
+ broken(!strcmp("", out)), /* Win9x */
+ "Expected the buffer to be untouched\n");
+ ok(r==0, "succeeded: r=%d\n", r);
+ ok(GetLastError()==0xdeadbeef,
+ "last error %u\n", GetLastError());
+
/* format placeholder with no specifier */
SetLastError(0xdeadbeef);
memcpy(out, init_buf, sizeof(init_buf));
@@ -898,6 +939,15 @@ static void test_message_allocate_buffer(void)
* in any case be safe for FormatMessageA to allocate in the manner that
* MSDN suggests. */
+ SetLastError(0xdeadbeef);
+ buf = (char *)0xdeadbeef;
+ ret = FormatMessageA(FORMAT_MESSAGE_FROM_STRING | FORMAT_MESSAGE_ALLOCATE_BUFFER,
+ "", 0, 0, (char *)&buf, 0, NULL);
+ ok(ret == 0, "Expected FormatMessageA to return 0, got %u\n", ret);
+ ok(buf == NULL, "Expected output buffer pointer to be NULL\n");
+ ok(GetLastError() == 0xdeadbeef,
+ "Expected last error to be untouched, got %u\n", GetLastError());
+
buf = (char *)0xdeadbeef;
ret = FormatMessageA(FORMAT_MESSAGE_FROM_STRING | FORMAT_MESSAGE_ALLOCATE_BUFFER,
"test", 0, 0, (char *)&buf, 0, NULL);
@@ -966,6 +1016,7 @@ static void test_message_allocate_buffer(void)
static void test_message_allocate_buffer_wide(void)
{
+ static const WCHAR empty[] = {0};
static const WCHAR test[] = {'t','e','s','t',0};
DWORD ret;
@@ -979,13 +1030,29 @@ static void test_message_allocate_buffer_wide(void)
return;
}
- /* While MSDN suggests that FormatMessageA allocates a buffer whose size is
+ /* While MSDN suggests that FormatMessageW allocates a buffer whose size is
* the larger of the output string and the requested buffer size, the tests
* will not try to determine the actual size of the buffer allocated, as
* the return value of LocalSize cannot be trusted for the purpose, and it should
- * in any case be safe for FormatMessageA to allocate in the manner that
+ * in any case be safe for FormatMessageW to allocate in the manner that
* MSDN suggests. */
+ if (0) /* crashes on Windows */
+ {
+ buf = (WCHAR *)0xdeadbeef;
+ ret = FormatMessageW(FORMAT_MESSAGE_FROM_STRING | FORMAT_MESSAGE_ALLOCATE_BUFFER,
+ NULL, 0, 0, (WCHAR *)&buf, 0, NULL);
+ }
+
+ SetLastError(0xdeadbeef);
+ buf = (WCHAR *)0xdeadbeef;
+ ret = FormatMessageW(FORMAT_MESSAGE_FROM_STRING | FORMAT_MESSAGE_ALLOCATE_BUFFER,
+ empty, 0, 0, (WCHAR *)&buf, 0, NULL);
+ ok(ret == 0, "Expected FormatMessageW to return 0, got %u\n", ret);
+ ok(buf == NULL, "Expected output buffer pointer to be NULL\n");
+ ok(GetLastError() == 0xdeadbeef,
+ "Expected last error to be untouched, got %u\n", GetLastError());
+
buf = (WCHAR *)0xdeadbeef;
ret = FormatMessageW(FORMAT_MESSAGE_FROM_STRING | FORMAT_MESSAGE_ALLOCATE_BUFFER,
test, 0, 0, (WCHAR *)&buf, 0, NULL);
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