[PATCH v2 1/5] libcsupport: Added futimens() and utimensat()

Ryan Long ryan.long at oarcorp.com
Thu May 6 19:50:45 UTC 2021


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
---
 cpukit/Makefile.am                 |   2 +
 cpukit/include/rtems/libio_.h      |  60 +++++++++-
 cpukit/libcsupport/src/futimens.c  |  87 ++++++++++++++
 cpukit/libcsupport/src/utimensat.c | 239 +++++++++++++++++++++++++++++++++++++
 spec/build/cpukit/librtemscpu.yml  |   2 +
 5 files changed, 387 insertions(+), 3 deletions(-)
 create mode 100644 cpukit/libcsupport/src/futimens.c
 create mode 100644 cpukit/libcsupport/src/utimensat.c

diff --git a/cpukit/Makefile.am b/cpukit/Makefile.am
index b0df610..29b4207 100644
--- a/cpukit/Makefile.am
+++ b/cpukit/Makefile.am
@@ -262,6 +262,8 @@ librtemscpu_a_SOURCES += libcsupport/src/unmount.c
 librtemscpu_a_SOURCES += libcsupport/src/__usrenv.c
 librtemscpu_a_SOURCES += libcsupport/src/utime.c
 librtemscpu_a_SOURCES += libcsupport/src/utimes.c
+librtemscpu_a_SOURCES += libcsupport/src/futimens.c
+librtemscpu_a_SOURCES += libcsupport/src/utimensat.c
 librtemscpu_a_SOURCES += libcsupport/src/utsname.c
 librtemscpu_a_SOURCES += libcsupport/src/vprintk.c
 librtemscpu_a_SOURCES += libcsupport/src/write.c
diff --git a/cpukit/include/rtems/libio_.h b/cpukit/include/rtems/libio_.h
index e9eb462..7a0a169 100644
--- a/cpukit/include/rtems/libio_.h
+++ b/cpukit/include/rtems/libio_.h
@@ -2,13 +2,12 @@
  * @file
  *
  * @brief LibIO Internal Interface
- * 
+ *
  * This file is the libio internal interface.
  */
 
 /*
- *  COPYRIGHT (c) 1989-2011.
- *  On-Line Applications Research Corporation (OAR).
+ *  COPYRIGHT (C) 1989, 2021 On-Line Applications Research Corporation (OAR).
  *
  *  Modifications to support reference counting in the file system are
  *  Copyright (c) 2012 embedded brains GmbH.
@@ -357,6 +356,61 @@ static inline void rtems_filesystem_instance_unlock(
   (*mt_entry->ops->unlock_h)( mt_entry );
 }
 
+/* Prototypes for functions used between utimensat() and futimens() */
+
+/**
+ * @brief Checks the tv_sec member of a timespec struct
+ *
+ * @param[in] time The timespec struct to be validated
+ *
+ * Ensures that the value in the tv_sec member is non-negative.
+ *
+ * @retval Returns true if the tv_sec member is a valid value, otherwise false.
+ */
+bool rtems_filesystem_utime_tv_sec_valid( struct timespec time );
+
+/**
+ * @brief Checks the tv_nsec member of a timespec struct
+ *
+ * Ensures that the value in the tv_nsec member is equal to either
+ * UTIME_NOW, UTIME_OMIT, or a value greater-than or equal to zero
+ * and less than a billion.
+ *
+ * @param[in] time The timespec struct to be validated
+ *
+ * @retval Returns true if tv_nsec member is a valid value, otherwise false.
+ */
+bool rtems_filesystem_utime_tv_nsec_valid( struct timespec time );
+
+/**
+ * @brief Determines if the process has write permissions to a file
+ *
+ * Checks that the process has the same userID as the file and whether the
+ * file has write permissions.
+ *
+ * @param[in] currentloc The current location to a file
+ * @param[in] fstat_h The file handler of @currentloc
+ *
+ * @retval Returns 0 if the process has write permissions, otherwise -1.
+ */
+int rtems_filesystem_utime_check_permissions(
+  const rtems_filesystem_location_info_t *currentloc,
+  const struct timespec times[2]
+);
+
+/**
+ * @brief Checks @times and updates @new_times
+ *
+ * @param[in] times The timespec struct to be checked
+ * @param[in,out] new_times The timespec struct to contain the updated time
+ *
+ * @retval Returns 0 if the time was update, otherwise -1.
+ */
+int rtems_filesystem_utime_check_times(
+  const struct timespec times[2],
+  struct timespec new_times[2]
+);
+
 /*
  *  File Descriptor Routine Prototypes
  */
diff --git a/cpukit/libcsupport/src/futimens.c b/cpukit/libcsupport/src/futimens.c
new file mode 100644
index 0000000..c2ef9da
--- /dev/null
+++ b/cpukit/libcsupport/src/futimens.c
@@ -0,0 +1,87 @@
+/* SPDX-License-Identifier: BSD-2-Clause */
+
+/**
+ *  @file
+ *
+ *  @ingroup libcsupport
+ *
+ *  @brief Set file access and modification times based on file descriptor in
+ *  nanoseconds.
+ */
+
+/*
+ * COPYRIGHT (C) 1989, 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 <sys/stat.h>
+#include <rtems/libio_.h>
+
+#include <fcntl.h>
+#include <stdlib.h>
+#include <string.h>
+
+/**
+ *  https://pubs.opengroup.org/onlinepubs/9699919799.2008edition/functions/futimens.html
+ *
+ *  Set file access and modification times
+ */
+int futimens(
+  int                    fd,
+  const struct timespec  times[2]
+)
+{
+  int rv;
+  rtems_libio_t *iop;
+  struct timespec new_times[2];
+  const rtems_filesystem_location_info_t *currentloc = NULL;
+
+  LIBIO_GET_IOP_WITH_ACCESS( fd, iop, LIBIO_FLAGS_READ, EBADF );
+
+  currentloc = &iop->pathinfo;
+
+  rv = rtems_filesystem_utime_check_times( times, new_times );
+  if ( rv != 0 ) {
+    rtems_libio_iop_drop( iop );
+    return rv;
+  }
+
+  rv = rtems_filesystem_utime_check_permissions( currentloc, times );
+  if ( rv != 0 ) {
+    rtems_libio_iop_drop( iop );
+    return rv;
+  }
+
+  rv = (*currentloc->mt_entry->ops->utimens_h)(
+    currentloc,
+    new_times
+  );
+
+  rtems_libio_iop_drop( iop );
+
+  return rv;
+}
diff --git a/cpukit/libcsupport/src/utimensat.c b/cpukit/libcsupport/src/utimensat.c
new file mode 100644
index 0000000..1cd42cb
--- /dev/null
+++ b/cpukit/libcsupport/src/utimensat.c
@@ -0,0 +1,239 @@
+/* SPDX-License-Identifier: BSD-2-Clause */
+
+/**
+ *  @file
+ *
+ *  @ingroup libcsupport
+ *
+ *  @brief Set file access and modification times in nanoseconds.
+ */
+
+/*
+ * COPYRIGHT (C) 1989, 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 <fcntl.h>
+#include <string.h>
+
+/* Verify that the seconds value is non-negative */
+bool rtems_filesystem_utime_tv_sec_valid(struct timespec time)
+{
+  if ( time.tv_sec < 0 ) {
+    return false;
+  }
+
+  return true;
+}
+
+/*
+ * 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 > 999999999 ) {
+    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;
+
+  memset( &st, 0, sizeof(st) );
+
+  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_check_times(
+  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 ) {
+    new_times[0].tv_sec = 0;
+    new_times[0].tv_nsec = UTIME_NOW;
+    new_times[1].tv_sec = 0;
+    new_times[1].tv_nsec = 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 ( !rtems_filesystem_utime_tv_sec_valid( new_times[0] ) ) {
+    rtems_set_errno_and_return_minus_one( EINVAL );
+  }
+
+  if ( !rtems_filesystem_utime_tv_sec_valid( 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 );
+  }
+
+  currentloc = rtems_filesystem_eval_path_start( &ctx, path, eval_flags );
+
+  rv = rtems_filesystem_utime_check_times( times, new_times );
+  if ( rv != 0 ) {
+    rtems_filesystem_eval_path_cleanup( &ctx );
+    return rv;
+  }
+
+  rv = rtems_filesystem_utime_check_permissions( currentloc, times );
+  if ( rv != 0 ) {
+    rtems_filesystem_eval_path_cleanup( &ctx );
+    return rv;
+  }
+
+  rv = (*currentloc->mt_entry->ops->utimens_h)(
+    currentloc,
+    new_times
+  );
+
+  rtems_filesystem_eval_path_cleanup( &ctx );
+
+  return rv;
+}
diff --git a/spec/build/cpukit/librtemscpu.yml b/spec/build/cpukit/librtemscpu.yml
index a3a9ee4..9639051 100644
--- a/spec/build/cpukit/librtemscpu.yml
+++ b/spec/build/cpukit/librtemscpu.yml
@@ -761,6 +761,8 @@ source:
 - cpukit/libcsupport/src/unmount.c
 - cpukit/libcsupport/src/utime.c
 - cpukit/libcsupport/src/utimes.c
+- cpukit/libcsupport/src/futimens.c
+- cpukit/libcsupport/src/utimensat.c
 - cpukit/libcsupport/src/utsname.c
 - cpukit/libcsupport/src/vprintk.c
 - cpukit/libcsupport/src/write.c
-- 
1.8.3.1



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