libpci: i386-io-windows.h: Improve ProcessUserModeIOPL error message

[pciutils.git] / lib / i386-io-windows.h

diff --git a/lib/i386-io-windows.h b/lib/i386-io-windows.h
index 6cf3a25581135efacd54249dcfd70bb3d7985e13..6bb578cb40d74c0fccefc119e66e858ad8b9b4d3 100644 (file)
--- a/lib/i386-io-windows.h
+++ b/lib/i386-io-windows.h
@@ -35,12 +35,11 @@
 #define _inp(x) __inbyte(x)
 #define _inpw(x) __inword(x)
 #define _inpd(x) __indword(x)
-#elif defined(__CRTDLL__)
+#elif defined(__CRTDLL__) || (defined(__MSVCRT_VERSION__) && __MSVCRT_VERSION__ < 0x400)
 /*
- * Old CRTDLL library does not provide I/O port functions. Even it is the oldest
- * CRT library it exists also in 64-bit variant. Implement I/O port functions
- * via inline assembly just for 32-bit mode as 64-bit mode uses above <intrin.h>
- * header.
+ * Old 32-bit CRTDLL library and pre-4.00 MSVCRT library do not provide I/O
+ * port functions. As these libraries exist only in 32-bit mode variant,
+ * implement I/O port functions via 32-bit inline assembly.
  */
 static inline int _outp(unsigned short port, int databyte)
 {
@@ -108,16 +107,13 @@ unsigned long _inpd(unsigned short port);
  * function conflicts with some MSVC intrinsic.
  * MSVC supports inline assembly via __asm keyword in 32-bit mode only.
  * GCC version 4.9.0 and higher provides __builtin_ia32_readeflags_uXX()
- * builtin for XX-mode.
+ * builtin for XX-mode. This builtin is also available as __readeflags()
+ * function indirectly via <x86intrin.h> header file.
  */
 #if defined(_MSC_VER) && (_MSC_VER >= 1500 || (_MSC_VER >= 1400 && defined(__BUILDMACHINE__)))
 #pragma intrinsic(__readeflags)
 #elif defined(__GNUC__) && ((__GNUC__ == 4 && __GNUC_MINOR__ >= 9) || (__GNUC__ > 4))
-#ifdef __x86_64__
-#define __readeflags() __builtin_ia32_readeflags_u64()
-#else
-#define __readeflags() __builtin_ia32_readeflags_u32()
-#endif
+#include <x86intrin.h>
 #elif defined(_MSC_VER) && defined(_M_IX86)
 static inline unsigned int
 __readeflags(void)
@@ -777,10 +773,13 @@ find_and_open_process_for_query(LPCSTR exe_file)
   EnumProcessesProt MyEnumProcesses;
   HMODULE kernel32, psapi;
   UINT prev_error_mode;
-  WCHAR path[MAX_PATH];
+  DWORD partial_retry;
+  BOOL found_process;
   DWORD size, length;
   DWORD *processes;
   HANDLE process;
+  LPWSTR path;
+  DWORD error;
   DWORD count;
   DWORD i;
 
@@ -874,11 +873,72 @@ retry:
       if (!process)
         continue;
 
+      /*
+       * Set initial buffer size to 256 (wide) characters.
+       * Final path length on the modern NT-based systems can be also larger.
+       */
+      size = 256;
+      found_process = FALSE;
+      partial_retry = 0;
+
+retry_path:
+      path = (LPWSTR)LocalAlloc(LPTR, size * sizeof(*path));
+      if (!path)
+        goto end_path;
+
       if (MyGetProcessImageFileNameW)
-        length = MyGetProcessImageFileNameW(process, path, sizeof(path)/sizeof(*path));
+        length = MyGetProcessImageFileNameW(process, path, size);
       else
-        length = MyGetModuleFileNameExW(process, NULL, path, sizeof(path)/sizeof(*path));
+        length = MyGetModuleFileNameExW(process, NULL, path, size);
+
+      error = GetLastError();
+
+      /*
+       * GetModuleFileNameEx() returns zero and signal error ERROR_PARTIAL_COPY
+       * when remote process is in the middle of updating its module table.
+       * Sleep 10 ms and try again, max 10 attempts.
+       */
+      if (!MyGetProcessImageFileNameW)
+        {
+          if (length == 0 && error == ERROR_PARTIAL_COPY && partial_retry++ < 10)
+            {
+              Sleep(10);
+              goto retry_path;
+            }
+          partial_retry = 0;
+        }
+
+      /*
+       * When buffer is too small then function GetModuleFileNameEx() returns
+       * its size argument on older systems (Windows XP) or its size minus
+       * argument one on new systems (Windows 10) without signalling any error.
+       * Function GetProcessImageFileNameW() on the other hand returns zero
+       * value and signals error ERROR_INSUFFICIENT_BUFFER. So in all these
+       * cases call function again with larger buffer.
+       */
+
+      if (MyGetProcessImageFileNameW && length == 0 && error != ERROR_INSUFFICIENT_BUFFER)
+        goto end_path;
+
+      if ((MyGetProcessImageFileNameW && length == 0) ||
+          (!MyGetProcessImageFileNameW && (length == size || length == size-1)))
+        {
+          LocalFree(path);
+          size *= 2;
+          goto retry_path;
+        }
+
       if (length && check_process_name(path, length, exe_file))
+        found_process = TRUE;
+
+end_path:
+      if (path)
+        {
+          LocalFree(path);
+          path = NULL;
+        }
+
+      if (found_process)
         break;
 
       CloseHandle(process);
@@ -1283,7 +1343,8 @@ intel_setup_io(struct pci_access *a)
   /* On NT-based systems issue ProcessUserModeIOPL syscall which changes IOPL to 3. */
   if (!SetProcessUserModeIOPL())
     {
-      a->warning("NT ProcessUserModeIOPL call failed with error: %lu.", (unsigned long int)GetLastError());
+      DWORD error = GetLastError();
+      a->debug("NT ProcessUserModeIOPL call failed: %s.", error == ERROR_INVALID_FUNCTION ? "Not Implemented" : error == ERROR_PRIVILEGE_NOT_HELD ? "Access Denied" : "Operation Failed");
       return 0;
     }