Cleanup: move overflow safe alloc code into libsquashfs

There were only a hand full of instances outside libsquashfs that used
the alloc code. In most cases, the thing allocated hat its size derived
from something already in memory anyway, so it is safe to assume its
size fits into a size_t.

At the same time, the opencoded Windows path conversion functions are
all unified into a single helper function.

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

3 files changed, 47 insertions, 24 deletions

diff --git a/lib/compat/Makemodule.am b/lib/compat/Makemodule.am
index fb37b46..7137f2c 100644
--- a/lib/compat/Makemodule.am
+++ b/lib/compat/Makemodule.am
@@ -1,5 +1,6 @@
 libcompat_a_SOURCES = lib/compat/getline.c lib/compat/getsubopt.c
 libcompat_a_SOURCES += lib/compat/strndup.c lib/compat/mockups.c
 libcompat_a_SOURCES += lib/compat/chdir.c include/compat.h
+libcompat_a_SOURCES += lib/compat/path_to_windows.c
 
 noinst_LIBRARIES += libcompat.a
diff --git a/lib/compat/chdir.c b/lib/compat/chdir.c
index b1b2d0c..04dcf17 100644
--- a/lib/compat/chdir.c
+++ b/lib/compat/chdir.c
@@ -10,37 +10,16 @@
 #include "util/util.h"
 
 #ifdef _WIN32
-#define WIN32_LEAN_AND_MEAN
-#include <windows.h>
 #include <stdlib.h>
 
 int chdir(const char *path)
 {
-	WCHAR *wpath, *ptr;
-	DWORD length;
+	WCHAR *wpath;
 	int ret;
 
-	length = MultiByteToWideChar(CP_UTF8, 0, path, -1, NULL, 0);
-	if (length <= 0) {
-		fprintf(stderr, "Converting '%s' to UTF-16: %ld\n",
-			path, GetLastError());
-		return -1;
-	}
-
-	wpath = alloc_array(sizeof(wpath[0]), length + 1);
-	if (wpath == NULL) {
-		fprintf(stderr, "Converting '%s' to UTF-16: out of memory\n",
-			path);
+	wpath = path_to_windows(path);
+	if (wpath == NULL)
 		return -1;
-	}
-
-	MultiByteToWideChar(CP_UTF8, 0, path, -1, wpath, length + 1);
-	wpath[length] = '\0';
-
-	for (ptr = wpath; *ptr != '\0'; ++ptr) {
-		if (*ptr == '/')
-			*ptr = '\\';
-	}
 
 	if (!SetCurrentDirectoryW(wpath)) {
 		fprintf(stderr, "Switching to directory '%s': %ld\n",
diff --git a/lib/compat/path_to_windows.c b/lib/compat/path_to_windows.c
new file mode 100644
index 0000000..ff3a5d2
--- /dev/null
+++ b/lib/compat/path_to_windows.c
@@ -0,0 +1,43 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later */
+/*
+ * path_to_windows.c
+ *
+ * Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
+ */
+#include "config.h"
+#include "compat.h"
+
+#include <stdlib.h>
+#include <stdio.h>
+
+#if defined(_WIN32) || defined(__WINDOWS__)
+WCHAR *path_to_windows(const char *input)
+{
+	WCHAR *wpath, *ptr;
+	DWORD length;
+
+	length = MultiByteToWideChar(CP_UTF8, 0, input, -1, NULL, 0);
+	if (length <= 0) {
+		fprintf(stderr, "Converting UTF-8 path to UTF-16: %ld\n",
+			GetLastError());
+		return NULL;
+	}
+
+	wpath = calloc(sizeof(wpath[0]), length + 1);
+	if (wpath == NULL) {
+		fprintf(stderr,
+			"Converting UTF-8 path to UTF-16: out of memory\n");
+		return NULL;
+	}
+
+	MultiByteToWideChar(CP_UTF8, 0, input, -1, wpath, length + 1);
+	wpath[length] = '\0';
+
+	for (ptr = wpath; *ptr != '\0'; ++ptr) {
+		if (*ptr == '/')
+			*ptr = '\\';
+	}
+
+	return wpath;
+}
+#endif