Add support for reallocarray libc function (#24775)

Fixes: #24771

Author: sbc100

system/lib/libc/musl/src/malloc/reallocarray.c

@@ -0,0 +1,17 @@
+#define _BSD_SOURCE
+#include <errno.h>
+#include <stdlib.h>
+
+#ifdef __EMSCRIPTEN__
+/* Must be weak so that lsan can override */
+weak
+#endif
+void *reallocarray(void *ptr, size_t m, size_t n)
+{
+	if (n && m > -1 / n) {
+		errno = ENOMEM;
+		return 0;
+	}
+
+	return realloc(ptr, m * n);
+}

test/code_size/test_codesize_hello_dylink_all.json

@@ -1,7 +1,7 @@
 {
   "a.out.js": 246735,
-  "a.out.nodebug.wasm": 597789,
-  "total": 844524,
+  "a.out.nodebug.wasm": 597855,
+  "total": 844590,
   "sent": [
     "IMG_Init",
     "IMG_Load",
@@ -2962,6 +2962,7 @@
     "readv",
     "realloc",
     "realloc_in_place",
+    "reallocarray",
     "realpath",
     "recv",
     "recvfrom",
@@ -4656,6 +4657,7 @@
     "$readlink",
     "$readlinkat",
     "$readv",
+    "$reallocarray",
     "$realpath",
     "$recv",
     "$recvfrom",

test/other/test_reallocarray.c

@@ -0,0 +1,21 @@
+#include <assert.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+
+int main(void) {
+  char* p = calloc(4, sizeof(char));
+  assert(p);
+
+  strcpy(p, "foo");
+  puts(p);
+
+  p = reallocarray(p, 32, sizeof(char));
+  assert(p);
+
+  strcpy(p, "foobar");
+  puts(p);
+
+  free(p);
+  return 0;
+}

test/other/test_reallocarray.out

@@ -0,0 +1,2 @@
+foo
+foobar

test/test_other.py

@@ -16395,3 +16395,6 @@ def test_TextDecoder_invalid(self):
 
     err = self.expect_fail([EMCC, test_file('hello_world.c'), '-sTEXTDECODER=3'])
     self.assertContained('#error "TEXTDECODER must be either 1 or 2"', err)
+
+  def test_reallocarray(self):
+    self.do_other_test('test_reallocarray.c')

tools/system_libs.py

@@ -1294,6 +1294,10 @@ def get_files(self):
         path='system/lib/libc/musl/src/linux',
         filenames=['getdents.c', 'gettid.c', 'utimes.c', 'statx.c', 'wait4.c', 'wait3.c'])
 
+    libc_files += files_in_path(
+        path='system/lib/libc/musl/src/malloc',
+        filenames=['reallocarray.c'])
+
     libc_files += files_in_path(
         path='system/lib/libc/musl/src/sched',
         filenames=['sched_yield.c'])