diff options
Diffstat (limited to 'sysdeps/posix')
| -rw-r--r-- | sysdeps/posix/readv.c | 2 | ||||
| -rw-r--r-- | sysdeps/posix/writev.c | 45 |
2 files changed, 39 insertions, 8 deletions
diff --git a/sysdeps/posix/readv.c b/sysdeps/posix/readv.c index 89fe1af..988ede5 100644 --- a/sysdeps/posix/readv.c +++ b/sysdeps/posix/readv.c @@ -38,7 +38,7 @@ __readv (fd, vector, count) char *buffer; char *buffer_start; size_t bytes; - int bytes_read; + ssize_t bytes_read; int i; bool use_malloc = false; diff --git a/sysdeps/posix/writev.c b/sysdeps/posix/writev.c index f92ff1c..dc2c806 100644 --- a/sysdeps/posix/writev.c +++ b/sysdeps/posix/writev.c @@ -1,4 +1,4 @@ -/* Copyright (C) 1991, 1992, 1996, 1997 Free Software Foundation, Inc. +/* Copyright (C) 1991, 1992, 1996, 1997, 2002 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 @@ -19,6 +19,9 @@ #include <stdlib.h> #include <unistd.h> #include <string.h> +#include <limits.h> +#include <stdbool.h> +#include <sys/param.h> #include <sys/uio.h> /* Write data pointed by the buffers described by VECTOR, which @@ -35,23 +38,46 @@ __writev (fd, vector, 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) - bytes += vector[i].iov_len; + { + /* Check for ssize_t overflow. */ + if (SSIZE_MAX - bytes < vector[i].iov_len) + { + errno = EINVAL; + return -1; + } + bytes += vector[i].iov_len; + } - /* Allocate a temporary buffer to hold the data. */ - buffer = (char *) __alloca (bytes); + /* 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. Use 512k as the limit. */ + if (bytes < 512 * 1024) + buffer = (char *) __alloca (bytes); + else + { + 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) { -#define min(a, b) ((a) > (b) ? (b) : (a)) - size_t copy = min (vector[i].iov_len, to_copy); + size_t copy = MIN (vector[i].iov_len, to_copy); bp = __mempcpy ((void *) bp, (void *) vector[i].iov_base, copy); @@ -60,7 +86,12 @@ __writev (fd, vector, count) break; } - return __write (fd, buffer, bytes); + bytes_written = __write (fd, buffer, bytes); + + if (use_malloc) + free (buffer); + + return bytes_written; } #ifndef __writev weak_alias (__writev, writev) |