Add needed functions to glibc-compat for pkg

ports/glibc-compat/src/openat.c

+/*
+ * Copyright 2015 The Native Client Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+#include <fcntl.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <limits.h>
+#include <dirent.h>
+#include <errno.h>
+#include <stdlib.h>
+#include <stdio.h>
+
+// xgetcwd is pulled from toybox lib/xwrap.c
+static char *xgetcwd(void) {
+  char *buf = (char*)malloc(sizeof(char) * (PATH_MAX+1));
+  if (buf == NULL) {
+    fprintf(stderr, "malloc failed\n");
+    exit(1);
+  }
+  buf = getcwd(buf, PATH_MAX+1);
+  if (!buf) {
+    perror("xgetcwd");
+    exit(1);
+  }
+  return buf;
+}
+
+// The following functions are pulled from toybox nacl.patch
+#define _AT_WRAP_START(A)                             \
+  int fchdir_err = 0;                                 \
+  char *save = xgetcwd();                             \
+  if (!save) {                                        \
+    perror("fd_wrapper_"A);                           \
+    exit(1);                                          \
+  }                                                   \
+  if (dirfd != AT_FDCWD) {                            \
+    fchdir_err = fchdir(dirfd);                       \
+    if (fchdir_err == -1)                             \
+      perror("fchdir");                               \
+  }
+
+#define _AT_WRAP_END(A)                 \
+  if (dirfd != AT_FDCWD) chdir(save);   \
+  free(save);
+
+int openat(int dirfd, const char *pathname, int flags, ...) {
+  _AT_WRAP_START("openat")
+    printf("New dir is: %s\n", xgetcwd());
+  int fd = open(pathname, flags);
+  _AT_WRAP_END("openat")
+  return fd;
+}
+
+int fstatat(int dirfd, const char *pathname, struct stat *buf, int flags) {
+  // We are going to ignore flags here.
+  //if (flags) perror_exit("fstatat_flags");
+  _AT_WRAP_START("fstatat")
+  int result;
+  if (flags & AT_SYMLINK_NOFOLLOW)
+    result = lstat(pathname, buf);
+  else
+    result = stat(pathname, buf);
+  _AT_WRAP_END("fstatat")
+  return result;
+}
+
+int fchmodat(int dirfd, const char *pathname, mode_t mode, int flags) {
+  // We are going to ignore flags here.
+  //if (flags) perror_exit("fchmodat_flags");
+  _AT_WRAP_START("fchmodat")
+  int result = chmod(pathname, mode);
+  _AT_WRAP_END("fchmodat")
+  return result;
+}
+
+int readlinkat(int dirfd, const char *pathname, char *buf, size_t bufsiz) {
+  _AT_WRAP_START("readlinkat")
+  int result = readlink(pathname, buf, bufsiz);
+  _AT_WRAP_END("readlinkat")
+  return result;
+}
+
+int unlinkat(int dirfd, const char *pathname, int flags) {
+  // We are going to ignore flags here.
+  //if (flags) perror_exit("unlinkat_flags");
+  _AT_WRAP_START("unlinkat")
+  int result;
+  if(flags & AT_REMOVEDIR) {
+    result = rmdir(pathname);
+  } else {
+    result = unlink(pathname);
+  }
+  _AT_WRAP_END("unlinkat")
+  return result;
+}
+
+int faccessat(int dirfd, const char *pathname, int mode, int flags) {
+  //if (flags) perror_exit("faccessat_flags");
+  _AT_WRAP_START("faccessat")
+  int result = access(pathname, mode);
+  _AT_WRAP_END("faccessat")
+  return result;
+}
+
+DIR *fdopendir(int dirfd) {
+  _AT_WRAP_START("fdopendir")
+  DIR *dir;
+  if (fchdir_err) {
+    perror("fdopendir: ");
+  }
+  dir = opendir(".");
+  _AT_WRAP_END("fdopendir")
+  return dir;
+}
+
+int mkdirat(int dirfd, const char *pathname, mode_t mode) {
+  _AT_WRAP_START("mkdirat")
+  int result = mkdir(pathname, mode);
+  _AT_WRAP_END("mkdirat")
+  return result;
+}
+
+int mknodat(int dirfd, const char *pathname, mode_t mode, dev_t dev) {
+  fprintf(stderr, "mknod not supported\n");
+  return 1;
+}
+
+int fchownat(int dirfd, const char *pathname, uid_t owner,
+    gid_t group, int flags) {
+  _AT_WRAP_START("fchownat")
+  int result = chown(pathname, owner, group);
+  _AT_WRAP_END("fchownat")
+  return result;
+}
+
+int symlinkat(const char *oldpath, int dirfd, const char *newpath) {
+  _AT_WRAP_START("symlinkat")
+  int result = symlink(oldpath, newpath);
+  _AT_WRAP_END("symlinkat")
+  return result;
+}
+
+int linkat(int olddirfd, const char *oldpath,
+    int newdirfd, const char *newpath, int flags) {
+  int result;
+  if ((oldpath[0] == '/') && (newpath[0] == '/')) {
+    result = link(oldpath, newpath);
+  } else {
+    errno = EINVAL;
+    result = -1;
+  }
+  // We do not support double linking.
+  return result;
+}