1 files changed, 53 insertions, 0 deletions
diff --git a/src/libunixonacid/access_at.c b/src/libunixonacid/access_at.c
new file mode 100644
index 0000000..c66f5d4
--- /dev/null
+++ b/src/libunixonacid/access_at.c
@@ -0,0 +1,53 @@
+/* ISC license. */
+
+#include <skalibs/sysdeps.h>
+
+#ifdef SKALIBS_HASOPENAT
+
+#ifndef _ATFILE_SOURCE
+#define _ATFILE_SOURCE
+#endif
+
+#include <skalibs/nonposix.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <skalibs/unix-transactional.h>
+
+int access_at (int dirfd, char const *file, int amode, unsigned int flag)
+{
+  return faccessat(dirfd, file, amode, flag ? AT_EACCESS : 0) ;
+}
+
+#else
+
+#include <errno.h>
+#include <unistd.h>
+#include <skalibs/djbunix.h>
+#include <skalibs/unix-transactional.h>
+
+int access_at (int dirfd, char const *file, int amode, unsigned int flag)
+{
+  int fdhere ;
+  if (getuid() != geteuid() || getgid() != getegid())
+    return (errno = ENOSYS, -1) ;
+  (void)flag ;
+  fdhere = open_read(".") ;
+  if (fdhere < 0) return -1 ;
+  if (fd_chdir(dirfd) < 0)
+  {
+    fd_close(fdhere) ;
+    return -1 ;
+  }
+  if (access(file, amode) < 0)
+  {
+    int e = errno ;
+    fd_chdir(fdhere) ;
+    fd_close(fdhere) ;
+    return (errno = e, -1) ;
+  }
+  fd_chdir(fdhere) ;
+  fd_close(fdhere) ;
+  return 0 ;
+}
+
+#endif