4f294c247f
This patch mainly copies and modifies files existing in the current libc implementing minix specific functions. To keep consisten with the NetBSD libc, we remove namespace stubs and we use "namespace.h" and weak links.
136 lines
2.7 KiB
C
136 lines
2.7 KiB
C
#include <sys/cdefs.h>
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#include <lib.h>
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#include "namespace.h"
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#include <assert.h>
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#include <errno.h>
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#include <limits.h>
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#include <stdlib.h>
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#include <string.h>
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#include <sys/stat.h>
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#include <sys/param.h>
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#include <sys/uio.h>
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#include <unistd.h>
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#define VECTORIO_READ 1
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#define VECTORIO_WRITE 2
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#ifdef __weak_alias
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__weak_alias(writev, _writev)
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__weak_alias(readv, _readv)
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#endif
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static ssize_t vectorio_buffer(int fildes, const struct iovec *iov,
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int iovcnt, int readwrite, ssize_t totallen)
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{
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char *buffer;
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int iovidx, errno_saved;
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ssize_t copied, len, r;
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/* allocate buffer */
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buffer = (char *) malloc(totallen);
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if (!buffer)
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return -1;
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/* perform the actual read/write for the entire buffer */
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switch (readwrite)
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{
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case VECTORIO_READ:
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/* first read, then copy buffers (only part read) */
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r = read(fildes, buffer, totallen);
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copied = 0;
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iovidx = 0;
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while (copied < r)
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{
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assert(iovidx < iovcnt);
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len = MIN(r - copied, iov[iovidx].iov_len);
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memcpy(iov[iovidx++].iov_base, buffer + copied, len);
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copied += len;
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}
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assert(r < 0 || r == copied);
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break;
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case VECTORIO_WRITE:
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/* first copy buffers, then write */
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copied = 0;
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for (iovidx = 0; iovidx < iovcnt; iovidx++)
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{
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memcpy(buffer + copied, iov[iovidx].iov_base,
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iov[iovidx].iov_len);
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copied += iov[iovidx].iov_len;
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}
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assert(copied == totallen);
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r = write(fildes, buffer, totallen);
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break;
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default:
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assert(0);
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errno = EINVAL;
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r = -1;
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}
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/* free the buffer, keeping errno unchanged */
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errno_saved = errno;
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free(buffer);
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errno = errno_saved;
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return r;
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}
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static ssize_t vectorio(int fildes, const struct iovec *iov,
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int iovcnt, int readwrite)
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{
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int i;
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ssize_t totallen;
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/* parameter sanity checks */
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if (iovcnt > IOV_MAX)
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{
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errno = EINVAL;
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return -1;
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}
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totallen = 0;
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for (i = 0; i < iovcnt; i++)
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{
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/* don't read/write anything in case of possible overflow */
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if ((ssize_t) (totallen + iov[i].iov_len) < totallen)
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{
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errno = EINVAL;
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return -1;
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}
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totallen += iov[i].iov_len;
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/* report on NULL pointers */
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if (iov[i].iov_len && !iov[i].iov_base)
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{
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errno = EFAULT;
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return -1;
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}
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}
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/* anything to do? */
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if (totallen == 0)
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return 0;
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/*
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* there aught to be a system call here; instead we use an intermediate
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* buffer; this is preferred over multiple read/write calls because
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* this function has to be atomic
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*/
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return vectorio_buffer(fildes, iov, iovcnt, readwrite, totallen);
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}
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ssize_t readv(int fildes, const struct iovec *iov, int iovcnt)
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{
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return vectorio(fildes, iov, iovcnt, VECTORIO_READ);
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}
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ssize_t writev(int fildes, const struct iovec *iov, int iovcnt)
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{
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return vectorio(fildes, iov, iovcnt, VECTORIO_WRITE);
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}
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