libcompat: Add a helper to get/set OS error state

On Unix like OSes, this saves/restores errno, on Windows both errno
and GetLastError state are saved/restored.

This should make it simpler to preserve that across function calls.

Additionally, while tracking down uses of GetLastError, some places
where the error code was printed out directly where replaced with
instances of w32_perror.

Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>

1 files changed, 5 insertions, 27 deletions

diff --git a/lib/common/src/perror.c b/lib/common/src/perror.c
index 5f62748..edefc9e 100644
--- a/lib/common/src/perror.c
+++ b/lib/common/src/perror.c
@@ -8,22 +8,10 @@
 
 #include <stdio.h>
 
-#if defined(_WIN32) || defined(__WINDOWS__)
-#define WIN32_LEAN_AND_MEAN
-#include <windows.h>
-#else
-#include <errno.h>
-#include <string.h>
-#endif
-
 void sqfs_perror(const char *file, const char *action, int error_code)
 {
+	os_error_t syserror;
 	const char *errstr;
-#if defined(_WIN32) || defined(__WINDOWS__)
-	DWORD syserror = GetLastError();
-#else
-	int syserror = errno;
-#endif
 
 	switch (error_code) {
 	case SQFS_ERROR_ALLOC:
@@ -82,6 +70,7 @@ void sqfs_perror(const char *file, const char *action, int error_code)
 		break;
 	}
 
+	syserror = get_os_error_state();
 	if (file != NULL)
 		fprintf(stderr, "%s: ", file);
 
@@ -89,24 +78,13 @@ void sqfs_perror(const char *file, const char *action, int error_code)
 		fprintf(stderr, "%s: ", action);
 
 	fprintf(stderr, "%s.\n", errstr);
+	set_os_error_state(syserror);
 
 	if (error_code == SQFS_ERROR_IO) {
 #if defined(_WIN32) || defined(__WINDOWS__)
-		LPVOID msg = NULL;
-
-		FormatMessageA(FORMAT_MESSAGE_ALLOCATE_BUFFER |
-			       FORMAT_MESSAGE_FROM_SYSTEM |
-			       FORMAT_MESSAGE_IGNORE_INSERTS,
-			       NULL, syserror,
-			       MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
-			       (LPTSTR)&msg, 0, NULL);
-
-		fprintf(stderr, "OS error: %s\n", (const char *)msg);
-
-		if (msg != NULL)
-			LocalFree(msg);
+		w32_perror("OS error");
 #else
-		fprintf(stderr, "OS error: %s\n", strerror(syserror));
+		perror("OS error");
 #endif
 	}
 }