fix #1 failures to replace itself when TMPDIR and current file is not on

the same volume

Author: pmq20

CHANGELOG.md

@@ -5,6 +5,8 @@
 - Auto-update shall only run once in every 24 hours with help of the file `~/.libautoupdate`
 - add argument `force` to `autoupdate()` in order to force an auto-update check
 - add CI to test `autoupdate()`
+- fix failures to replace itself when TMPDIR and current file is not on the same volume
+  - https://github.com/pmq20/libautoupdate/issues/1
 
 ## v0.1.0
 

appveyor.yml

@@ -21,7 +21,7 @@ build_script:
 
     cd build
 
-    cmake -DBUILD_TESTS=ON -G"$env:GENERATOR" -DZLIB_INCLUDE_DIR:PATH=C:\projects\libautoupdate\zlib.$env:PlatformToolset.windesktop.msvcstl.dyn.rt-dyn.1.2.8.8\build\native\include -DZLIB_LIBRARY_RELEASE:FILEPATH=C:\projects\libautoupdate\zlib.$env:PlatformToolset.windesktop.msvcstl.dyn.rt-dyn.1.2.8.8\lib\native\$env:PlatformToolset\windesktop\msvcstl\dyn\rt-dyn\$env:Platform\RelWithDebInfo\zlib.lib ..
+    cmake -DBUILD_TESTS=ON -DCMAKE_BUILD_TYPE=Release -G"$env:GENERATOR" -DZLIB_INCLUDE_DIR:PATH=C:\projects\libautoupdate\zlib.$env:PlatformToolset.windesktop.msvcstl.dyn.rt-dyn.1.2.8.8\build\native\include -DZLIB_LIBRARY_RELEASE:FILEPATH=C:\projects\libautoupdate\zlib.$env:PlatformToolset.windesktop.msvcstl.dyn.rt-dyn.1.2.8.8\lib\native\$env:PlatformToolset\windesktop\msvcstl\dyn\rt-dyn\$env:Platform\RelWithDebInfo\zlib.lib ..
 
     cmake --build . --config Release
     

src/autoupdate.c

@@ -19,6 +19,7 @@
 #include <conio.h>
 #include <stdint.h>
 #include <stdlib.h> /* exit */
+#include <wchar.h>
 
 int autoupdate(
 	int argc,
@@ -492,6 +493,30 @@ int autoupdate(
 		free(body_buffer);
 		return 2;
 	}
+	/* Windows paths can never be longer than this. */
+	const size_t exec_path_len = 32768;
+	wchar_t exec_path[32768];
+	DWORD utf16_len = GetModuleFileNameW(NULL, exec_path, exec_path_len);
+	if (0 == utf16_len) {
+		fprintf(stderr, "Auto-update Failed: GetModuleFileNameW failed with GetLastError=%d\n", GetLastError());
+		free((void*)(tmpdir));
+		free(uncomp);
+		free(body_buffer);
+		return 2;
+	}
+	if (tmpdir[0] != exec_path[0]) {
+		free((void*)(tmpdir));
+		tmpdir = wcsdup(exec_path);
+		wchar_t *backslash = wcsrchr(tmpdir, L'\\');
+		if (NULL == backslash) {
+			fprintf(stderr, "Auto-update Failed: Cannot find an approriate tmpdir with %S\n", tmpdir);
+			free((void*)(tmpdir));
+			free(uncomp);
+			free(body_buffer);
+			return 2;
+		}
+		*backslash = 0;
+	}
 	wchar_t *tmpf = autoupdate_tmpf(tmpdir, "exe");
 	if (NULL == tmpf) {
 		fprintf(stderr, "Auto-update Failed: no temporary file available\n");
@@ -524,17 +549,6 @@ int autoupdate(
 	fclose(fp);
 	free(uncomp);
 	free(body_buffer);
-	/* Windows paths can never be longer than this. */
-	const size_t exec_path_len = 32768;
-	wchar_t exec_path[32768];
-	DWORD utf16_len = GetModuleFileNameW(NULL, exec_path, exec_path_len);
-	if (0 == utf16_len) {
-		fprintf(stderr, "Auto-update Failed: GetModuleFileNameW failed with GetLastError=%d\n", GetLastError());
-		DeleteFileW(tmpf);
-		free((void*)(tmpdir));
-		free((void*)(tmpf));
-		return 2;
-	}
 	// Backup
 	wchar_t *selftmpf = autoupdate_tmpf(tmpdir, "exe");
 	if (NULL == selftmpf) {