base: reallocarray

m4/usual.m4

@@ -205,7 +205,7 @@ dnl AC_CHECK_FUNCS(basename dirname) # unstable, provide always
 AC_CHECK_FUNCS(strlcpy strlcat memmem getpeereid sigaction sigqueue)
 AC_CHECK_FUNCS(inet_ntop inet_pton poll getline memrchr regcomp)
 AC_CHECK_FUNCS(err errx warn warnx getprogname setprogname)
-AC_CHECK_FUNCS(posix_memalign memalign valloc explicit_bzero memset_s)
+AC_CHECK_FUNCS(posix_memalign memalign valloc explicit_bzero memset_s reallocarray)
 AC_CHECK_FUNCS(getopt getopt_long getopt_long_only)
 AC_CHECK_FUNCS(fls flsl flsll ffs ffsl ffsll)
 AC_CHECK_FUNCS(fnmatch mbsnrtowcs nl_langinfo strtod_l)

test/test_base.c

@@ -74,9 +74,18 @@ static void test_misc(void *_p)
 end:;
 }
 
+static void test_reallocarray(void *_p)
+{
+	void *p;
+	p = reallocarray(NULL, 1, 1); tt_assert(p); free(p);
+	p = reallocarray(NULL, LLONG_MAX, LLONG_MAX); tt_assert(p == NULL);
+end:;
+}
+
 struct testcase_t base_tests[] = {
 	{ "ptr", test_ptr },
 	{ "misc", test_misc },
+	{ "reallocarray", test_reallocarray },
 	END_OF_TESTCASES
 };
 

usual/base.c

@@ -17,6 +17,7 @@
  */
 
 #include <usual/base.h>
+#include <usual/bits.h>
 
 #if defined(HAVE_MALLOC_H) && defined(__darwin__)
 #include <malloc.h>
@@ -51,3 +52,17 @@ int posix_memalign(void **ptr_p, size_t align, size_t len)
 }
 #endif
 
+#ifndef HAVE_REALLOCARRAY
+
+void *reallocarray(void *p, size_t count, size_t size)
+{
+	size_t total;
+	if (!safe_mul_size(&total, count, size)) {
+		errno = ENOMEM;
+		return NULL;
+	}
+	return realloc(p, total);
+}
+
+#endif
+

usual/base.h

@@ -324,5 +324,15 @@ static inline void *zmalloc(size_t len)
 int posix_memalign(void **ptr_p, size_t align, size_t len);
 #endif
 
+#ifndef HAVE_REALLOCARRAY
+#define reallocarray(a,b,c) usual_reallocarray(a,b,c)
+
+/**
+ * Same as realloc(), but safely calculates total size.
+ */
+void *reallocarray(void *p, size_t count, size_t size);
+
+#endif
+
 #endif