libc: Add support for readv() and write(). Also includes some cosmeti…

…c changes to some unrelated files.

lib/libc/Makefile

@@ -105,6 +105,7 @@ include wqueue/Make.defs
 include misc/Make.defs
 include ttrace/Make.defs
 include audio/Make.defs
+include uio/Make.defs
 
 # REVISIT: Backslash causes problems in $(COBJS) target
 DELIM := $(strip /)

lib/libc/README.txt

@@ -43,6 +43,7 @@ we have:
   stdlib    - stdlib.h
   string    - string.h
   time      - time.h
+  uio       - sys/uio.h
   unistd    - unistd.h
   wchar     - wchar.h
   wctype    - wctype.h

lib/libc/math.csv

@@ -93,6 +93,7 @@
 "rint", "math.h", "defined(CONFIG_HAVE_DOUBLE)  &&(defined(CONFIG_LIBM) || defined(CONFIG_ARCH_MATH))", "double", "double"
 "rintf", "math.h", "defined(CONFIG_LIBM) || defined(CONFIG_ARCH_MATH)", "float", "float"
 "rintl", "math.h", "defined(CONFIG_HAVE_LONG_DOUBLE)  &&(defined(CONFIG_LIBM) || defined(CONFIG_ARCH_MATH))", "long double", "long double"
+"readv", "sys/uio.h", "", "ssize_t", "int", "FAR const struct iovec *", "int"
 "round", "math.h", "defined(CONFIG_HAVE_DOUBLE)  &&(defined(CONFIG_LIBM) || defined(CONFIG_ARCH_MATH))", "double", "double"
 "roundf", "math.h", "defined(CONFIG_LIBM) || defined(CONFIG_ARCH_MATH)", "float", "float"
 "roundl", "math.h", "defined(CONFIG_HAVE_LONG_DOUBLE)  &&(defined(CONFIG_LIBM) || defined(CONFIG_ARCH_MATH))", "long double", "long double"
@@ -114,6 +115,7 @@
 "tanhf", "math.h", "defined(CONFIG_LIBM) || defined(CONFIG_ARCH_MATH)", "float", "float"
 "tanhl", "math.h", "defined(CONFIG_HAVE_LONG_DOUBLE)  &&(defined(CONFIG_LIBM) || defined(CONFIG_ARCH_MATH))", "long double", "long double"
 "tanl", "math.h", "defined(CONFIG_HAVE_LONG_DOUBLE)  &&(defined(CONFIG_LIBM) || defined(CONFIG_ARCH_MATH))", "long double", "long double"
+"writev", "sys/uio.h", "", "ssize_t", "int", "FAR const struct iovec *", "int"
 "y0", "math.h", "defined(CONFIG_HAVE_DOUBLE) && (defined(CONFIG_LIBM) || defined(CONFIG_ARCH_MATH))", "double", "double"
 "y0f", "math.h", "defined(CONFIG_LIBM) || defined(CONFIG_ARCH_MATH)", "float", "float"
 "y1", "math.h", "defined(CONFIG_HAVE_DOUBLE) && (defined(CONFIG_LIBM) || defined(CONFIG_ARCH_MATH))", "double", "double"

lib/libc/uio/Make.defs

@@ -0,0 +1,60 @@
+###########################################################################
+#
+# Copyright 2018 Samsung Electronics All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
+# either express or implied. See the License for the specific
+# language governing permissions and limitations under the License.
+#
+###########################################################################
+############################################################################
+# libc/uio/Make.defs
+#
+#   Copyright (C) 2017 Gregory Nutt. All rights reserved.
+#   Author: Gregory Nutt <[email protected]>
+#
+# 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.
+#
+############################################################################
+
+# Add the uio.h C files to the build
+
+CSRCS += lib_readv.c lib_writev.c
+
+# Add the uio.h directory to the build
+
+DEPPATH += --dep-path uio
+VPATH += :uio

lib/libc/uio/lib_readv.c

@@ -0,0 +1,142 @@
+/****************************************************************************
+ *
+ * Copyright 2018 Samsung Electronics All Rights Reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
+ * either express or implied. See the License for the specific
+ * language governing permissions and limitations under the License.
+ *
+ ****************************************************************************/
+/****************************************************************************
+ * libc/uio/lib_readv.c
+ *
+ *   Copyright (C) 2017 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <[email protected]>
+ *
+ * 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 <sys/types.h>
+#include <sys/uio.h>
+#include <unistd.h>
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: readv()
+ *
+ * Description:
+ *   The readv() function is equivalent to read(), except as described below.
+ *   The readv() function places the input data into the iovcnt buffers
+ *   specified by the members of the iov array: iov[0], iov[1], ...,
+ *   iov[iovcnt-1].  The iovcnt argument is valid if greater than 0 and less
+ *   than or equal to IOV_MAX as defined in limits.h.
+ *
+ *   Each iovec entry specifies the base address and length of an area in
+ *   memory where data should be placed.  The readv() function will always
+ *   fill an area completely before proceeding to the next.
+ *
+ *   Upon successful completion, readv() will mark for update the st_atime
+ *   field of the file.
+ *
+ * Input Parameters:
+ *   filedes - The open file descriptor for the file to be read
+ *   iov     - Array of read buffer descriptors
+ *   iovcnt  - Number of elements in iov[]
+ *
+ * Returned Value:
+ *   Upon successful completion, readv() will return a non-negative integer
+ *   indicating the number of bytes actually read.  Otherwise, the functions
+ *   will return -1 and set errno to indicate the error.  See read().
+ *
+ ****************************************************************************/
+
+ssize_t readv(int fildes, FAR const struct iovec *iov, int iovcnt)
+{
+	ssize_t ntotal;
+	ssize_t nread;
+	size_t remaining;
+	FAR uint8_t *buffer;
+	int i;
+
+	/* Process each entry in the struct iovec array */
+
+	for (i = 0, ntotal = 0; i < iovcnt; i++) {
+		/* Ignore zero-length reads */
+
+		if (iov[i].iov_len > 0) {
+			buffer    = iov[i].iov_base;
+			remaining = iov[i].iov_len;
+
+			/* Read repeatedly as necessary to fill buffer */
+
+			do {
+				/* NOTE:  read() is a cancellation point */
+
+				nread = read(fildes, buffer, remaining);
+
+				/* Check for a read error */
+
+				if (nread < 0) {
+					return nread;
+				}
+
+				/* Check for an end-of-file condition */
+
+				else if (nread == 0) {
+					return ntotal;
+				}
+
+				/* Update pointers and counts in order to handle partial
+				 * buffer reads.
+				 */
+
+				buffer    += nread;
+				remaining -= nread;
+				ntotal    += nread;
+			} while (remaining > 0);
+		}
+	}
+
+	return ntotal;
+}

lib/libc/uio/lib_writev.c

@@ -0,0 +1,161 @@
+/****************************************************************************
+ *
+ * Copyright 2018 Samsung Electronics All Rights Reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
+ * either express or implied. See the License for the specific
+ * language governing permissions and limitations under the License.
+ *
+ ****************************************************************************/
+/****************************************************************************
+ * libc/uio/lib_writev.c
+ *
+ *   Copyright (C) 2017 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <[email protected]>
+ *
+ * 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 <sys/types.h>
+#include <sys/uio.h>
+#include <unistd.h>
+#include <errno.h>
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: writev()
+ *
+ * Description:
+ *   The writev() function is equivalent to write(), except as described
+ *   below. The writev() function will gather output data from the iovcnt
+ *   buffers specified by the members of the iov array: iov[0], iov[1], ...,
+ *   iov[iovcnt-1]. The iovcnt argument is valid if greater than 0 and less
+ *   than or equal to IOV_MAX, as defined in limits.h.
+ *
+ *   Each iovec entry specifies the base address and length of an area in
+ *   memory from which data should be written. The writev() function always
+ *   writes a complete area before proceeding to the next.
+ *
+ *   If fildes refers to a regular file and all of the iov_len members in
+ *   the array pointed to by iov are 0, writev() will return 0 and have no
+ *   other effect. For other file types, the behavior is unspecified.
+ *
+ *   If the sum of the iov_len values is greater than SSIZE_MAX, the
+ *   operation will fail and no data will be transferred.
+ *
+ * Input Parameters:
+ *   filedes - The open file descriptor for the file to be read
+ *   iov     - Array of read buffer descriptors
+ *   iovcnt  - Number of elements in iov[]
+ *
+ * Returned Value:
+ *   Upon successful completion, writev() shall return the number of bytes
+ *   actually written. Otherwise, it shall return a value of -1, the file-
+ *   pointer shall remain unchanged, and errno shall be set to indicate an
+ *   error.
+ *
+ ****************************************************************************/
+
+ssize_t writev(int fildes, FAR const struct iovec *iov, int iovcnt)
+{
+	ssize_t ntotal;
+	ssize_t nwritten;
+	size_t remaining;
+	FAR uint8_t *buffer;
+	off_t pos;
+	int i;
+
+	/* Get the current file position in case we have to reset it */
+
+	pos = lseek(fildes, 0, SEEK_CUR);
+	if (pos == (off_t)-1) {
+		return ERROR;
+	}
+
+	/* Process each entry in the struct iovec array */
+
+	for (i = 0, ntotal = 0; i < iovcnt; i++) {
+		/* Ignore zero-length writes */
+
+		if (iov[i].iov_len > 0) {
+			buffer    = iov[i].iov_base;
+			remaining = iov[i].iov_len;
+
+			/* Write repeatedly as necessary to write the entire buffer */
+
+			do {
+				/* NOTE:  write() is a cancellation point */
+
+				nwritten = write(fildes, buffer, remaining);
+
+				/* Check for a write error */
+
+				if (nwritten < 0) {
+					/* Save the errno value */
+
+					int save = get_errno();
+
+					/* Restore the file position */
+
+					(void)lseek(fildes, pos, SEEK_SET);
+
+					/* Restore the errno value */
+
+					set_errno(save);
+					return ERROR;
+				}
+
+				/* Update pointers and counts in order to handle partial
+				 * buffer writes.
+				 */
+
+				buffer    += nwritten;
+				remaining -= nwritten;
+				ntotal    += nwritten;
+			} while (remaining > 0);
+		}
+	}
+
+	return ntotal;
+}