[PATCH v9 5/5] xcopy: Don't attempt to copy a file to itself.

[Joe Souza]

From: Joe Souza

---
 programs/xcopy/xcopy.c  | 46 +++++++++++++++++++++++++++++++++++++++--
 programs/xcopy/xcopy.h  |  1 +
 programs/xcopy/xcopy.rc |  1 +
 3 files changed, 46 insertions(+), 2 deletions(-)

diff --git a/programs/xcopy/xcopy.c b/programs/xcopy/xcopy.c
index a8bd14f1616..2adfa402a31 100644
--- a/programs/xcopy/xcopy.c
+++ b/programs/xcopy/xcopy.c
@@ -325,6 +325,37 @@ static BOOL XCOPY_ProcessExcludeList(WCHAR* parms) {
     return FALSE;
 }

+/* =========================================================================
+ * XCOPY_IsSameFile
+ *
+ * Checks if the two paths reference to the same file.
+ * Copied from WCMD builtins.c, and tab-adjusted.
+ * ========================================================================= */
+static BOOL XCOPY_IsSameFile(const WCHAR *name1, const WCHAR *name2)
+{
+    BOOL ret = FALSE;
+    HANDLE file1 = INVALID_HANDLE_VALUE, file2 = INVALID_HANDLE_VALUE;
+    BY_HANDLE_FILE_INFORMATION info1, info2;
+
+    file1 = CreateFileW(name1, 0, FILE_SHARE_DELETE | FILE_SHARE_READ | FILE_SHARE_WRITE, 0, OPEN_EXISTING, 0, 0);
+    if (file1 == INVALID_HANDLE_VALUE || !GetFileInformationByHandle(file1, &info1))
+        goto end;
+
+    file2 = CreateFileW(name2, 0, FILE_SHARE_DELETE | FILE_SHARE_READ | FILE_SHARE_WRITE, 0, OPEN_EXISTING, 0, 0);
+    if (file2 == INVALID_HANDLE_VALUE || !GetFileInformationByHandle(file2, &info2))
+        goto end;
+
+    ret = info1.dwVolumeSerialNumber == info2.dwVolumeSerialNumber
+        && info1.nFileIndexHigh == info2.nFileIndexHigh
+        && info1.nFileIndexLow == info2.nFileIndexLow;
+end:
+    if (file1 != INVALID_HANDLE_VALUE)
+        CloseHandle(file1);
+    if (file2 != INVALID_HANDLE_VALUE)
+        CloseHandle(file2);
+    return ret;
+}
+
 /* =========================================================================
    XCOPY_DoCopy - Recursive function to copy files based on input parms
      of a stem and a spec
@@ -345,7 +376,7 @@ static int XCOPY_DoCopy(WCHAR *srcstem, WCHAR *srcspec,
     WCHAR           *inputpath, *outputpath;
     BOOL            copiedFile = FALSE;
     DWORD           destAttribs, srcAttribs;
-    BOOL            skipFile, quitCopy = FALSE;
+    BOOL            skipFile, quitCopy = FALSE, wantStatus = FALSE, sameFile = FALSE;
     int             ret = 0;

/* Allocate some working memory on heap to minimize footprint */
@@ -490,6 +521,12 @@ static int XCOPY_DoCopy(WCHAR *srcstem, WCHAR *srcspec,
                 }
             }

+            /* Don't copy a file over itself. */
+            if (!skipFile && XCOPY_IsSameFile(copyFrom, copyTo)) {
+                skipFile = quitCopy = wantStatus = sameFile = TRUE;
+                ret = RC_INITERROR;
+            }
+
             if (!skipFile &&
                 destAttribs != INVALID_FILE_ATTRIBUTES && !(flags & OPT_NOPROMPT)) {
                 DWORD count;
@@ -525,14 +562,19 @@ static int XCOPY_DoCopy(WCHAR *srcstem, WCHAR *srcspec,
             }

/* Output a status message */
-            if (!skipFile) {
+            if (!skipFile || wantStatus) {
                 if (!(flags & OPT_QUIET)) {
                     if (flags & OPT_FULL)
                         XCOPY_wprintf(L"%1 -> %2\n", copyFrom, copyTo);
                     else
                         XCOPY_wprintf(L"%1\n", copyFrom);
                 }
+                if (sameFile) {
+                    XCOPY_wprintf(XCOPY_LoadMessage(STRING_NOCOPYTOSELF));
+                }
+            }

+            if (!skipFile) {
                 /* If allowing overwriting of read only files, remove any
                    write protection                                       */
                 if ((destAttribs & FILE_ATTRIBUTE_READONLY) &&
diff --git a/programs/xcopy/xcopy.h b/programs/xcopy/xcopy.h
index 1ed9e20c45b..70b0935ba2c 100644
--- a/programs/xcopy/xcopy.h
+++ b/programs/xcopy/xcopy.h
@@ -69,3 +69,4 @@
 #define STRING_FILE_CHAR        115
 #define STRING_DIR_CHAR         116
 #define STRING_HELP             117
+#define STRING_NOCOPYTOSELF     118
diff --git a/programs/xcopy/xcopy.rc b/programs/xcopy/xcopy.rc
index c61e4da88fd..b12eeb4b068 100644
--- a/programs/xcopy/xcopy.rc
+++ b/programs/xcopy/xcopy.rc
@@ -79,4 +79,5 @@ Where:\n\
 \t\tIf no date is supplied, only copy if destination is older\n\
 \t\tthan source.\n\n"

+    STRING_NOCOPYTOSELF, "File cannot be copied to itself.\n"
 }