Fix issue with AT_FDCWD

OSX doesn’t like AT_FDCWD in it’s fcntl, but getcwd does the job.
Also fixed an issue with absolute paths in the process.

src/fs_base_utime_generic.hpp

@@ -25,9 +25,7 @@
 #include <sys/stat.h>
 #include <sys/time.h>
 
-#if __APPLE__
-#import <sys/param.h> /* MAXPATHLEN */
-#endif
+#include "futimesat.hpp" /* futimesat replacement */
 
 #ifndef UTIME_NOW
 # define UTIME_NOW  ((1l << 30) - 1l)
@@ -293,16 +291,7 @@ namespace fs
 
     if((flags & AT_SYMLINK_NOFOLLOW) == 0) {
 #if __APPLE__
-
-      char fullpath[MAXPATHLEN];
-
-      if (fcntl(dirfd,F_GETPATH,fullpath) < 0)
-        return (errno=errno,-1);
-
-      if (strlcat(fullpath, "/", MAXPATHLEN) > MAXPATHLEN || strlcat(fullpath, path.c_str(), MAXPATHLEN) > MAXPATHLEN)
-          return (errno=ENAMETOOLONG,-1);
-
-      return ::utimes(fullpath,tvp);
+      return _futimesat(dirfd,path.c_str(),tvp);
 #else
       return ::futimesat(dirfd,path.c_str(),tvp);
 #endif

src/futimesat.cpp

@@ -0,0 +1,5 @@
+#include "futimesat.hpp"
+
+#ifdef __APPLE__
+#include "futimesat_osx.icpp"
+#endif

src/futimesat.hpp

@@ -0,0 +1,9 @@
+#ifndef __UTIMESAT_HPP__
+#define __UTIMESAT_HPP__
+
+#if __APPLE__
+int
+_futimesat(int dirfd, const char* path, struct timeval *tvp);
+#endif
+
+#endif

src/futimesat_osx.icpp

@@ -0,0 +1,35 @@
+#include <unistd.h>
+#include <string.h>
+#include <fcntl.h>
+#include <err.h>
+#include <sys/errno.h>
+#include <sys/time.h>
+#include <sys/param.h> /* MAXPATHLEN */
+
+
+int
+_futimesat(int fd, const char* path, struct timeval *tvp) {
+  char fullpath[MAXPATHLEN];
+
+  // Handle absolute paths
+  if(path[0] == '/') {
+    return ::utimes(path,tvp);
+  }
+
+  // OS X 10.12 (at least) has an issue with using AT_FDCWD in this specific call.
+  if (fd == AT_FDCWD) {
+    if (getcwd((char*)fullpath, MAXPATHLEN) == NULL) {
+      return -1;
+    }
+  } else {
+    if (fcntl(fd,F_GETPATH,fullpath) < 0) {
+      return -1;
+    }
+  }
+
+  if (strlcat(fullpath, "/", MAXPATHLEN) > MAXPATHLEN || strlcat(fullpath, path, MAXPATHLEN) > MAXPATHLEN) {
+    return (errno=ENAMETOOLONG,-1);
+  }
+
+  return ::utimes(fullpath,tvp);;
+}