ap/app/zte_comm/nvserver/file.c

/* vi: set sw=4 ts=4: */
/*
 * Utility routines.
 *
 * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
 *
 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
 */
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <errno.h>
#include <unistd.h>

#define  FAST_FUNC

ssize_t FAST_FUNC safe_read(int fd, void *buf, size_t count)
{
	ssize_t n;

	for (;;) {
		n = read(fd, buf, count);
		if (n >= 0 || errno != EINTR)
			break;
		/* Some callers set errno=0, are upset when they see EINTR.
		 * Returning EINTR is wrong since we retry read(),
		 * the "error" was transient.
		 */
		errno = 0;
		/* repeat the read() */
	}

	return n;
}

/*
 * Read all of the supplied buffer from a file.
 * This does multiple reads as necessary.
 * Returns the amount read, or -1 on an error.
 * A short read is returned on an end of file.
 */
ssize_t FAST_FUNC full_read(int fd, void *buf, size_t len)
{
	ssize_t cc;
	ssize_t total;

	total = 0;

	while (len) {
		cc = safe_read(fd, buf, len);

		if (cc < 0) {
			if (total) {
				/* we already have some! */
				/* user can do another read to know the error code */
				return total;
			}
			return cc; /* read() returns -1 on failure. */
		}
		if (cc == 0)
			break;
		buf = ((char *)buf) + cc;
		total += cc;
		len -= cc;
	}

	return total;
}

ssize_t FAST_FUNC read_close(int fd, void *buf, size_t size)
{
	/*int e;*/
	size = full_read(fd, buf, size);
	/*e = errno;*/
	close(fd);
	/*errno = e;*/
	return size;
}

ssize_t FAST_FUNC open_read_close(const char *filename, void *buf, size_t size)
{
	int fd = open(filename, O_RDONLY);
	if (fd < 0)
		return fd;
	return read_close(fd, buf, size);
}

ssize_t FAST_FUNC safe_write(int fd, const void *buf, size_t count)
{
	ssize_t n;

	for (;;) {
		n = write(fd, buf, count);
		if (n >= 0 || errno != EINTR)
			break;
		/* Some callers set errno=0, are upset when they see EINTR.
		 * Returning EINTR is wrong since we retry write(),
		 * the "error" was transient.
		 */
		errno = 0;
		/* repeat the write() */
	}

	return n;
}

ssize_t FAST_FUNC full_write(int fd, const void *buf, size_t len)
{
	ssize_t cc;
	ssize_t total;

	total = 0;

	while (len) {
		cc = safe_write(fd, buf, len);

		if (cc < 0) {
			if (total) {
				/* we already wrote some! */
				/* user can do another write to know the error code */
				return total;
			}
			return cc;  /* write() returns -1 on failure. */
		}

		total += cc;
		buf = ((const char *)buf) + cc;
		len -= cc;
	}

	return total;
}