runtime: fix memory error in canonicalize_file_name

Fixes #46 and reverts #47. As stated in #46, the solution works for
musl, glibc etc. However, the code in stub.c is executed by uclibc
and uclibc doesn't allocate the target buffer in realpath. The
memory error occured while running df for 10min with DFS.

1 files changed, 16 insertions, 0 deletions

diff --git a/test/Runtime/POSIX/CanonicalizeFileName.c b/test/Runtime/POSIX/CanonicalizeFileName.c
new file mode 100644
index 00000000..56b02327
--- /dev/null
+++ b/test/Runtime/POSIX/CanonicalizeFileName.c
@@ -0,0 +1,16 @@
+// REQUIRES: not-darwin
+// RUN: %llvmgcc %s -Wall -emit-llvm -g -O0 -c -o %t.bc
+// RUN: rm -rf %t.klee-out
+// RUN: %klee --output-dir=%t.klee-out --libc=uclibc --posix-runtime --exit-on-error %t.bc
+
+#define _GNU_SOURCE
+#include <limits.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+int main(int argc, char * argv[]) {
+  char cwd[PATH_MAX] = {0};
+
+  if (!getcwd(cwd, PATH_MAX)) exit(EXIT_FAILURE);
+  if (!canonicalize_file_name(cwd)) exit(EXIT_FAILURE);
+}