libs/libc/unistd.h: Add getuid() and getgid() to match Michael Jung's setuid() and setgid().

libs/libc/unistd/Make.defs

@@ -37,7 +37,8 @@
 
 CSRCS += lib_access.c lib_daemon.c lib_swab.c lib_sysconf.c
 CSRCS += lib_getopt.c lib_getoptargp.c lib_getoptindp.c lib_getoptoptp.c
-CSRCS += lib_sleep.c lib_usleep.c lib_setuid.c lib_setgid.c
+CSRCS += lib_sleep.c lib_usleep.c
+CSRCS += lib_setuid.c lib_setgid.c lib_getuid.c lib_getgid.c
 
 ifneq ($(CONFIG_DISABLE_ENVIRON),y)
 CSRCS += lib_chdir.c lib_getcwd.c

libs/libc/unistd/lib_getgid.c

@@ -0,0 +1,69 @@
+/****************************************************************************
+ * libs/libc/unistd/lib_aetgid.c
+ *
+ *   Copyright (C) 2019 Gregory Nutt. All rights reserved.
+ *   Author:  Gregory Nutt <gnutt@nuttx.net>
+ *
+ * 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.
+ * 3. Neither the name NuttX nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * 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.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <unistd.h>
+#include <errno.h>
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: getgid
+ *
+ * Description:
+ *   The getgid() function will the real group ID of the calling task group.
+ *
+ * Input Parameters:
+ *   None.
+ *
+ * Returned Value:
+ *   The getgid() function is always be successful and no return value is
+ *   reserved to indicate an error..
+ *
+ ****************************************************************************/
+
+int setgid(gid_t gid)
+{
+  /* Return group identity 'root' with a gid value of 0. */
+
+  return 0;
+}

libs/libc/unistd/lib_getuid.c

@@ -0,0 +1,69 @@
+/****************************************************************************
+ * libs/libc/unistd/lib_setuid.c
+ *
+ *   Copyright (C) 2019 Gregory Nutt. All rights reserved.
+ *   Author:  Gregory Nutt <gnutt@nuttx.net>
+ *
+ * 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.
+ * 3. Neither the name NuttX nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * 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.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <unistd.h>
+#include <errno.h>
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: getuid
+ *
+ * Description:
+ *   The getuid() function will return the real user ID of the calling process.
+ *
+ * Input Parameters:
+ *   None
+ *
+ * Returned Value:
+ *   Zero if successful and -1 in case of failure, in which case errno is set
+ *   appropriately.
+ *
+ ****************************************************************************/
+
+int setuid(uid_t uid)
+{
+  /* Return the user identity 'root' with a uid value of 0. */
+
+  return 0;
+}