From a85aa08276898bfebf0c4f53e0ed2080e65e3f1d Mon Sep 17 00:00:00 2001
From: Andrea Mazzoleni <amadvance@users.sourceforge.net>
Date: Thu, 4 Apr 2013 19:30:24 +0200
Subject: [PATCH] Prints also the Windows GetLastError() in strerror().

---
 handle.c |  3 +--
 mingw.c  | 32 ++++++++++++++++++++++++++++++++
 mingw.h  |  6 ++++++
 parity.c |  2 +-
 4 files changed, 40 insertions(+), 3 deletions(-)

diff --git a/handle.c b/handle.c
index 80dd215b..0ba280d7 100644
--- a/handle.c
+++ b/handle.c
@@ -220,7 +220,7 @@ int handle_read(struct snapraid_handle* handle, struct snapraid_block* block, un
 #endif
 
 		if (read_ret < 0) {
-			fprintf(out, "Error reading file '%s' at offset %"PRIu64". %s.\n", handle->path, offset, strerror(errno));
+			fprintf(out, "Error reading file '%s' at offset %"PRIu64" for size %u. %s.\n", handle->path, offset + count, read_size - count, strerror(errno));
 			return -1;
 		}
 		if (read_ret == 0) {
@@ -230,7 +230,6 @@ int handle_read(struct snapraid_handle* handle, struct snapraid_block* block, un
 
 		count += read_ret;
 	} while (count < read_size);
-		
 
 	/* pad with 0 */
 	if (read_size < block_size) {
diff --git a/mingw.c b/mingw.c
index 725ce324..988fed82 100644
--- a/mingw.c
+++ b/mingw.c
@@ -17,6 +17,8 @@
 
 #include "portable.h"
 
+#include "util.h"
+
 #ifdef __MINGW32__ /* Only for MingW */
 
 /* Adds missing Windows declaration */
@@ -64,6 +66,11 @@ static BOOL (WINAPI* ptr_GetFileInformationByHandleEx)(HANDLE, DWORD, LPVOID, DW
  */
 static BOOLEAN (WINAPI* ptr_CreateSymbolicLinkW)(LPWSTR, LPWSTR, DWORD);
 
+/**
+ * Description of the last error.
+ */
+static char* last_error;
+
 void os_init(void)
 {
 	HMODULE kernel32 = GetModuleHandle("KERNEL32.DLL");
@@ -85,10 +92,14 @@ void os_init(void)
 			ptr_SetThreadExecutionState(WIN32_ES_CONTINUOUS | WIN32_ES_SYSTEM_REQUIRED);
 		}
 	}
+
+	last_error = 0;
 }
 
 void os_done(void)
 {
+	free(last_error);
+
 	/* restore the normal execution level */
 	if (ptr_SetThreadExecutionState) {
 		ptr_SetThreadExecutionState(WIN32_ES_CONTINUOUS);
@@ -1037,5 +1048,26 @@ int devuuid(uint64_t device, char* uuid, size_t uuid_size)
 	return 0;
 }
 
+#undef strerror
+
+const char* windows_strerror(int err)
+{
+	/* get the normal C error from the specified err */
+	const char* str = strerror(err);
+	size_t len = strlen(str);
+
+	/* adds space for GetLastError() */
+	len += 32;
+
+	/* reallocate */
+	free(last_error);
+	last_error = malloc(len);
+	if (!last_error)
+		return str;
+
+	snprintf(last_error, len, "%s [%u]", str, (unsigned)GetLastError());
+	return last_error;
+}
+
 #endif
 
diff --git a/mingw.h b/mingw.h
index 94640dc2..3726d11c 100644
--- a/mingw.h
+++ b/mingw.h
@@ -68,6 +68,7 @@
 #define readlink windows_readlink
 #define symlink windows_symlink
 #define link windows_link
+#define strerror windows_strerror
 
 /* We have nano second support */
 #define STAT_NSEC(st) (st)->st_mtimensec
@@ -250,6 +251,11 @@ int windows_symlink(const char* existing, const char* file);
  */
 int windows_link(const char* existing, const char* file);
 
+/**
+ * Like strerror().
+ */
+const char* windows_strerror(int err);
+
 #endif
 #endif
 
diff --git a/parity.c b/parity.c
index adf64475..55c3781a 100644
--- a/parity.c
+++ b/parity.c
@@ -393,7 +393,7 @@ int parity_read(struct snapraid_parity* parity, block_off_t pos, unsigned char*
 		read_ret = read(parity->f, block_buffer + count, block_size - count);
 #endif
 		if (read_ret < 0) {
-			fprintf(out, "Error reading file '%s' at offset %"PRIu64". %s.\n", parity->path, offset, strerror(errno));
+			fprintf(out, "Error reading file '%s' at offset %"PRIu64" for size %u. %s.\n", parity->path, offset + count, block_size - count, strerror(errno));
 			return -1;
 		}
 		if (read_ret == 0) {