libcomposefs/lcfs-writer.c: fix build without reallocarray

If reallocarray is not available (e.g. on uclibc), use realloc to avoid the following build failure with uclibc: composefs/libcomposefs/lcfs-writer.c: In function 'lcfs_node_add_child': composefs/libcomposefs/lcfs-writer.c:886:24: error: implicit declaration of function 'reallocarray' [-Werror=implicit-function-declaration] 886 | new_children = reallocarray(parent->children, sizeof(*parent->children), | ^~~~~~~~~~~~ composefs/libcomposefs/lcfs-writer.c:886:22: error: assignment to 'struct lcfs_node_s **' from 'int' makes pointer from integer without a cast [-Werror=int-conversion] 886 | new_children = reallocarray(parent->children, sizeof(*parent->children), | ^ Fixes: - http://autobuild.buildroot.org/results/38470213c86091d14c59716cddcccd555f875705 Signed-off-by: Fabrice Fontaine <[email protected]>
containers · Dec 11, 2023 · 3358d54 · 3358d54
1 parent 9a9cd59
commit 3358d54
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diff --git a/configure.ac b/configure.ac
@@ -204,7 +204,7 @@ AC_FUNC_ERROR_AT_LINE
 AC_FUNC_FSEEKO
 AC_HEADER_MAJOR
 AC_FUNC_MMAP
-AC_CHECK_FUNCS([getcwd memset munmap strdup])
+AC_CHECK_FUNCS([getcwd memset munmap reallocarray strdup])
 
 AC_SUBST(PKGCONFIG_REQUIRES)
 AC_SUBST(PKGCONFIG_REQUIRES_PRIVATELY)

diff --git a/libcomposefs/lcfs-utils.h b/libcomposefs/lcfs-utils.h
@@ -42,6 +42,21 @@ static inline char *memdup(const char *s, size_t len)
 	return s2;
 }
 
+static inline bool size_multiply_overflow(size_t size, size_t nmemb)
+{
+	return nmemb != 0 && size > (SIZE_MAX / nmemb);
+}
+
+#ifndef HAVE_REALLOCARRAY
+static inline void *reallocarray(void *ptr, size_t nmemb, size_t size)
+{
+	if (size_multiply_overflow(size, nmemb))
+		return NULL;
+
+	return realloc(ptr, size * nmemb ?: 1);
+}
+#endif
+
 static inline int hexdigit(char c)
 {
 	if (c >= '0' && c <= '9')