From 2dbe6afe7c13af9790f2d37d3be3c8fa3262bd27 Mon Sep 17 00:00:00 2001 From: Ulrich Drepper Date: Fri, 3 Apr 2009 17:23:13 +0000 Subject: * sysdeps/unix/sysv/linux/kernel-features.h: Define __ASSUME_COMPLETE_READV_WRITEV. * sysdeps/unix/sysv/linux/readv.c: No need for userlevel fallback with modern kernels. * sysdeps/unix/sysv/linux/writev.c: Likewise. * sysdeps/posix/readv.c: Since read is a cancellation point we have to free a possible malloced buffer in case of cancellation. * sysdeps/posix/writev.c: Likewise for write. c2009-04-01 Ulrich Drepper --- sysdeps/posix/readv.c | 40 +++++++++++++++++----------------------- sysdeps/posix/writev.c | 42 ++++++++++++++++++++---------------------- 2 files changed, 37 insertions(+), 45 deletions(-) (limited to 'sysdeps/posix') diff --git a/sysdeps/posix/readv.c b/sysdeps/posix/readv.c index f0e78e6662..50bcc91315 100644 --- a/sysdeps/posix/readv.c +++ b/sysdeps/posix/readv.c @@ -1,4 +1,4 @@ -/* Copyright (C) 1991, 1992, 1996, 1997, 2002 Free Software Foundation, Inc. +/* Copyright (C) 1991,1992,1996,1997,2002,2009 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 @@ -25,24 +25,24 @@ #include #include + +static void +ifree (char **ptrp) +{ + free (*ptrp); +} + /* Read data from file descriptor FD, and put the result in the - buffers described by VECTOR, which is a vector of COUNT `struct iovec's. + buffers described by VECTOR, which is a vector of COUNT 'struct iovec's. The buffers are filled in the order specified. - Operates just like `read' (see ) except that data are + Operates just like 'read' (see ) except that data are put in VECTOR instead of a contiguous buffer. */ ssize_t __libc_readv (int fd, const struct iovec *vector, int count) { - char *buffer; - char *buffer_start; - size_t bytes; - ssize_t bytes_read; - int i; - bool use_malloc = false; - /* Find the total number of bytes to be read. */ - bytes = 0; - for (i = 0; i < count; ++i) + size_t bytes = 0; + for (int i = 0; i < count; ++i) { /* Check for ssize_t overflow. */ if (SSIZE_MAX - bytes < vector[i].iov_len) @@ -57,28 +57,25 @@ __libc_readv (int fd, const struct iovec *vector, int count) 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 { - buffer = (char *) malloc (bytes); + malloced_buffer = buffer = (char *) malloc (bytes); if (buffer == NULL) - /* XXX I don't know whether it is acceptable to try reading - the data in chunks. Probably not so we just fail here. */ return -1; - - use_malloc = true; } /* Read the data. */ - bytes_read = __read (fd, buffer, bytes); + ssize_t bytes_read = __read (fd, buffer, bytes); if (bytes_read <= 0) return -1; /* Copy the data from BUFFER into the memory specified by VECTOR. */ bytes = bytes_read; - buffer_start = buffer; - for (i = 0; i < count; ++i) + for (int i = 0; i < count; ++i) { size_t copy = MIN (vector[i].iov_len, bytes); @@ -90,9 +87,6 @@ __libc_readv (int fd, const struct iovec *vector, int count) break; } - if (use_malloc) - free (buffer_start); - return bytes_read; } #ifndef __libc_readv diff --git a/sysdeps/posix/writev.c b/sysdeps/posix/writev.c index a347cc2eac..203cf9cebd 100644 --- a/sysdeps/posix/writev.c +++ b/sysdeps/posix/writev.c @@ -1,4 +1,4 @@ -/* Copyright (C) 1991, 1992, 1996, 1997, 2002 Free Software Foundation, Inc. +/* Copyright (C) 1991,1992,1996,1997,2002,2009 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 @@ -25,24 +25,25 @@ #include #include + +static void +ifree (char **ptrp) +{ + free (*ptrp); +} + + /* Write data pointed by the buffers described by VECTOR, which - is a vector of COUNT `struct iovec's, to file descriptor FD. + is a vector of COUNT 'struct iovec's, to file descriptor FD. The data is written in the order specified. - Operates just like `write' (see ) except that the data + Operates just like 'write' (see ) except that the data are taken from VECTOR instead of a contiguous buffer. */ ssize_t __libc_writev (int fd, const struct iovec *vector, int count) { - char *buffer; - register char *bp; - size_t bytes, to_copy; - ssize_t bytes_written; - int i; - bool use_malloc = false; - /* Find the total number of bytes to be written. */ - bytes = 0; - for (i = 0; i < count; ++i) + size_t bytes = 0; + for (int i = 0; i < count; ++i) { /* Check for ssize_t overflow. */ if (SSIZE_MAX - bytes < vector[i].iov_len) @@ -57,23 +58,23 @@ __libc_writev (int fd, const struct iovec *vector, int count) 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 { - buffer = (char *) malloc (bytes); + malloced_buffer = buffer = (char *) malloc (bytes); if (buffer == NULL) /* XXX I don't know whether it is acceptable to try writing the data in chunks. Probably not so we just fail here. */ return -1; - - use_malloc = true; } /* Copy the data into BUFFER. */ - to_copy = bytes; - bp = buffer; - for (i = 0; i < count; ++i) + size_t to_copy = bytes; + char *bp = buffer; + for (int i = 0; i < count; ++i) { size_t copy = MIN (vector[i].iov_len, to_copy); @@ -84,10 +85,7 @@ __libc_writev (int fd, const struct iovec *vector, int count) break; } - bytes_written = __write (fd, buffer, bytes); - - if (use_malloc) - free (buffer); + ssize_t bytes_written = __write (fd, buffer, bytes); return bytes_written; } -- cgit 1.4.1