diff options
Diffstat (limited to 'sysdeps/posix/preadv.c')
-rw-r--r-- | sysdeps/posix/preadv.c | 91 |
1 files changed, 7 insertions, 84 deletions
diff --git a/sysdeps/posix/preadv.c b/sysdeps/posix/preadv.c index 7539bf85a9..7819a938a1 100644 --- a/sysdeps/posix/preadv.c +++ b/sysdeps/posix/preadv.c @@ -1,4 +1,5 @@ -/* Copyright (C) 2009-2017 Free Software Foundation, Inc. +/* Read data into multiple buffers. Generic version. + Copyright (C) 2009-2017 Free Software Foundation, Inc. This file is part of the GNU C Library. The GNU C Library is free software; you can redistribute it and/or @@ -15,93 +16,15 @@ License along with the GNU C Library; if not, see <http://www.gnu.org/licenses/>. */ -#include <errno.h> -#include <stdlib.h> -#include <unistd.h> -#include <string.h> -#include <limits.h> -#include <stdbool.h> -#include <sys/param.h> -#if __WORDSIZE == 64 && !defined PREADV -/* Hide the preadv64 declaration. */ -# define preadv64 __redirect_preadv64 -#endif -#include <sys/uio.h> -#include <bits/wordsize.h> +#include <sys/types.h> + +#ifndef __OFF_T_MATCHES_OFF64_T -#ifndef PREADV # define PREADV preadv # define PREAD __pread # define OFF_T off_t -#endif - - -static void -ifree (char **ptrp) -{ - free (*ptrp); -} - - -/* Read data from file descriptor FD at the given position OFFSET - without change the file pointer, and put the result in the buffers - described by VECTOR, which is a vector of COUNT 'struct iovec's. - The buffers are filled in the order specified. Operates just like - 'pread' (see <unistd.h>) except that data are put in VECTOR instead - of a contiguous buffer. */ -ssize_t -PREADV (int fd, const struct iovec *vector, int count, OFF_T offset) -{ - /* Find the total number of bytes to be read. */ - size_t bytes = 0; - for (int i = 0; i < count; ++i) - { - /* Check for ssize_t overflow. */ - if (SSIZE_MAX - bytes < vector[i].iov_len) - { - __set_errno (EINVAL); - return -1; - } - bytes += vector[i].iov_len; - } - - /* Allocate a temporary buffer to hold the data. We should normally - use alloca since it's faster and does not require synchronization - with other threads. But we cannot if the amount of memory - required is too large. */ - char *buffer; - char *malloced_buffer __attribute__ ((__cleanup__ (ifree))) = NULL; - if (__libc_use_alloca (bytes)) - buffer = (char *) __alloca (bytes); - else - { - malloced_buffer = buffer = (char *) malloc (bytes); - if (buffer == NULL) - return -1; - } - - /* Read the data. */ - ssize_t bytes_read = PREAD (fd, buffer, bytes, offset); - if (bytes_read < 0) - return -1; - - /* Copy the data from BUFFER into the memory specified by VECTOR. */ - bytes = bytes_read; - for (int i = 0; i < count; ++i) - { - size_t copy = MIN (vector[i].iov_len, bytes); - - (void) memcpy ((void *) vector[i].iov_base, (void *) buffer, copy); +# include <sysdeps/posix/preadv_common.c> - buffer += copy; - bytes -= copy; - if (bytes == 0) - break; - } +libc_hidden_def (preadv) - return bytes_read; -} -#if __WORDSIZE == 64 && defined preadv64 -# undef preadv64 -strong_alias (preadv, preadv64) #endif |