libcsupport: Added futimens() and utimensat()

Created futimens.c and utimensat.c to add support for the POSIX
methods futimens() and utimensat().

utime() and utimes() are considered obsolote by POSIX, but RTEMS
will continue to support them.

Closes #4396

1 files changed, 225 insertions, 0 deletions

diff --git a/cpukit/libcsupport/src/utimensat.c b/cpukit/libcsupport/src/utimensat.c
new file mode 100644
index 0000000000..3e91b65aae
--- /dev/null
+++ b/cpukit/libcsupport/src/utimensat.c
@@ -0,0 +1,225 @@
+/* SPDX-License-Identifier: BSD-2-Clause */
+
+/**
+ *  @file
+ *
+ *  @ingroup libcsupport
+ *
+ *  @brief Set file access and modification times in nanoseconds.
+ */
+
+/*
+ * COPYRIGHT (C) 2021 On-Line Applications Research Corporation (OAR).
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <rtems/libio_.h>
+#include <rtems/score/todimpl.h>
+
+#include <fcntl.h>
+#include <string.h>
+
+/*
+ * Make sure that tv_nsec is either UTIME_NOW, UTIME_OMIT, a value
+ * greater than zero, or a value less-than a billion.
+ *
+ * These guidelines come from the description of the EINVAL errors on
+ * https://pubs.opengroup.org/onlinepubs/9699919799/functions/futimens.html
+ */
+bool rtems_filesystem_utime_tv_nsec_valid(struct timespec time)
+{
+  if ( time.tv_nsec == UTIME_NOW ) {
+    return true;
+  }
+
+  if ( time.tv_nsec == UTIME_OMIT ) {
+    return true;
+  }
+
+  if ( time.tv_nsec < 0 ) {
+    return false;
+  }
+
+  if ( time.tv_nsec >= TOD_NANOSECONDS_PER_SECOND ) {
+    return false;
+  }
+
+  return true;
+}
+
+/* Determine whether the access and modified timestamps can be updated */
+int rtems_filesystem_utime_check_permissions(
+  const rtems_filesystem_location_info_t * currentloc,
+  const struct timespec times[2]
+)
+{
+  struct stat st = {};
+  int rv;
+  bool write_access;
+
+  rv = (*currentloc->handlers->fstat_h)( currentloc, &st );
+  if ( rv != 0 ) {
+    rtems_set_errno_and_return_minus_one( ENOENT );
+  }
+
+  write_access = rtems_filesystem_check_access(
+    RTEMS_FS_PERMS_WRITE,
+    st.st_mode,
+    st.st_uid,
+    st.st_gid
+  );
+
+  /*
+   * The logic for the EACCES error is an inverted subset of the EPERM
+   * conditional according to the POSIX standard.
+   */
+  if ( (times == NULL) ||
+     ( (times[0].tv_nsec == UTIME_NOW) && (times[1].tv_nsec == UTIME_NOW) )) {
+      if ( !write_access ) {
+        rtems_set_errno_and_return_minus_one( EACCES );
+      }
+  } else {
+    if ( times[0].tv_nsec != UTIME_OMIT || times[1].tv_nsec != UTIME_OMIT ) {
+      if ( !write_access ) {
+        rtems_set_errno_and_return_minus_one( EPERM );
+      }
+    }
+  }
+
+  return 0;
+}
+
+/*
+ * Determine if the current time needs to be gotten, and then check
+ * whether the values in times are valid.
+ */
+int rtems_filesystem_utime_update(
+  const struct timespec times[2],
+  struct timespec new_times[2]
+)
+{
+  bool got_time = false;
+  struct timespec now;
+
+  /*
+   * If times is NULL, it's equivalent to adding UTIME_NOW in both time
+   * elements
+   */
+  if ( times == NULL ) {
+    _Timespec_Set( &new_times[0], 0, UTIME_NOW );
+    _Timespec_Set( &new_times[1], 0, UTIME_NOW );
+  } else {
+    new_times[0] = times[0];
+    new_times[1] = times[1];
+  }
+
+  if ( new_times[0].tv_nsec == UTIME_NOW ) {
+    clock_gettime( CLOCK_REALTIME, &now );
+    new_times[0] = now;
+    got_time = true;
+  }
+
+  if ( new_times[1].tv_nsec == UTIME_NOW ) {
+    if ( !got_time ) {
+      clock_gettime( CLOCK_REALTIME, &now );
+    }
+    new_times[1] = now;
+  }
+
+  if ( !_Timespec_Is_non_negative( &new_times[0] ) ) {
+    rtems_set_errno_and_return_minus_one( EINVAL );
+  }
+
+  if ( !_Timespec_Is_non_negative( &new_times[1] ) ) {
+    rtems_set_errno_and_return_minus_one( EINVAL );
+  }
+
+  if ( !rtems_filesystem_utime_tv_nsec_valid( new_times[0] ) ) {
+    rtems_set_errno_and_return_minus_one( EINVAL );
+  }
+
+  if ( !rtems_filesystem_utime_tv_nsec_valid( new_times[1] ) ) {
+    rtems_set_errno_and_return_minus_one( EINVAL );
+  }
+
+  return 0;
+}
+
+/**
+ *  https://pubs.opengroup.org/onlinepubs/9699919799.2008edition/functions/futimens.html
+ *
+ *  Set file access and modification times
+ */
+int utimensat(
+  int                    fd,
+  const char            *path,
+  const struct timespec  times[2],
+  int                    flag
+)
+{
+  int rv = 0;
+  rtems_filesystem_eval_path_context_t ctx;
+  int eval_flags = RTEMS_FS_FOLLOW_LINK;
+  const rtems_filesystem_location_info_t *currentloc = NULL;
+  struct timespec new_times[2];
+
+  /*
+   * RTEMS does not currently support operating on a real file descriptor
+   */
+  if ( fd != AT_FDCWD ) {
+    rtems_set_errno_and_return_minus_one( ENOSYS );
+  }
+
+  /*
+   * RTEMS does not currently support AT_SYMLINK_NOFOLLOW
+   */
+  if ( flag != 0 ) {
+    rtems_set_errno_and_return_minus_one( ENOSYS );
+  }
+
+  rv = rtems_filesystem_utime_update( times, new_times );
+  if ( rv != 0 ) {
+    return rv;
+  }
+
+  currentloc = rtems_filesystem_eval_path_start( &ctx, path, eval_flags );
+
+  rv = rtems_filesystem_utime_check_permissions( currentloc, times );
+  if ( rv != 0 ) {
+    rtems_filesystem_eval_path_cleanup( &ctx );
+    return rv;
+  }
+
+  rv = (*currentloc->mt_entry->ops->utime_h)(
+    currentloc,
+    new_times
+  );
+
+  rtems_filesystem_eval_path_cleanup( &ctx );
+
+  return rv;
+}