Added openat()/fstatat().

auto/unix

diff --git a/auto/unix b/auto/unix
index 5ee8f37..d786bb4 100755
--- a/auto/unix
+++ b/auto/unix
@@ -731,3 +731,17 @@
 ngx_feature_libs=
 ngx_feature_test="sysconf(_SC_NPROCESSORS_ONLN)"
 . auto/feature
+
+
+ngx_feature="openat(), fstatat()"
+ngx_feature_name="NGX_HAVE_OPENAT"
+ngx_feature_run=no
+ngx_feature_incs="#include <sys/types.h>
+                  #include <sys/stat.h>
+                  #include <fcntl.h>"
+ngx_feature_path=
+ngx_feature_libs=
+ngx_feature_test="struct stat sb;
+                  openat(AT_FDCWD, \".\", O_RDONLY|O_NOFOLLOW);
+                  fstatat(AT_FDCWD, \".\", &sb, AT_SYMLINK_NOFOLLOW);"
+. auto/feature

src/os/unix/ngx_errno.h

diff --git a/src/os/unix/ngx_errno.h b/src/os/unix/ngx_errno.h
index 092d05a..78af40b 100644
--- a/src/os/unix/ngx_errno.h
+++ b/src/os/unix/ngx_errno.h
@@ -48,6 +48,11 @@
 #define NGX_EILSEQ        EILSEQ
 #define NGX_ENOMOREFILES  0
 
+#if (NGX_HAVE_OPENAT)
+#define NGX_EMLINK        EMLINK
+#define NGX_ELOOP         ELOOP
+#endif
+
 #if (__hpux__)
 #define NGX_EAGAIN        EWOULDBLOCK
 #else

src/os/unix/ngx_files.h

diff --git a/src/os/unix/ngx_files.h b/src/os/unix/ngx_files.h
index abeb157..1526f9b 100644
--- a/src/os/unix/ngx_files.h
+++ b/src/os/unix/ngx_files.h
@@ -76,6 +76,10 @@
 #define NGX_FILE_APPEND          O_WRONLY|O_APPEND
 #define NGX_FILE_NONBLOCK        O_NONBLOCK
 
+#if (NGX_HAVE_OPENAT)
+#define NGX_FILE_NOFOLLOW        O_NOFOLLOW
+#endif
+
 #define NGX_FILE_DEFAULT_ACCESS  0644
 #define NGX_FILE_OWNER_ACCESS    0600
 
@@ -324,6 +328,21 @@
 size_t ngx_fs_bsize(u_char *name);
 
 
+#if (NGX_HAVE_OPENAT)
+
+#define ngx_openat_file(fd, name, mode, create, access)                      \
+    openat(fd, (const char *) name, mode|create, access)
+
+#define ngx_openat_file_n        "openat()"
+
+#define ngx_file_at_info(fd, name, sb, flag)                                 \
+    fstatat(fd, (const char *) name, sb, flag)
+
+#define ngx_file_at_info_n       "fstatat()"
+
+#endif
+
+
 #define ngx_stderr               STDERR_FILENO
 #define ngx_set_stderr(fd)       dup2(fd, STDERR_FILENO)
 #define ngx_set_stderr_n         "dup2(STDERR_FILENO)"