IABSD.fr/src/usr.bin/ssh/atomicio.c

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• Author : dtucker
  Date : 2019-01-24 02:42:23
  Hash : 82975832
  Message : Check for both EAGAIN and EWOULDBLOCK. This is a no-op in OpenBSD (they are the same value) but makes things easier in -portable where they may be distinct values. "sigh ok" deraadt@

• usr.bin/ssh/atomicio.c

• /* $OpenBSD: atomicio.c,v 1.30 2019/01/24 02:42:23 dtucker Exp $ */
  /*
   * Copyright (c) 2006 Damien Miller. All rights reserved.
   * Copyright (c) 2005 Anil Madhavapeddy. All rights reserved.
   * Copyright (c) 1995,1999 Theo de Raadt.  All rights reserved.
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   *
   * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
   * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
   * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
   * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
   * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
   * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
   * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
   * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
   * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   */
  
  #include <sys/uio.h>
  
  #include <errno.h>
  #include <poll.h>
  #include <string.h>
  #include <unistd.h>
  #include <limits.h>
  
  #include "atomicio.h"
  
  /*
   * ensure all of data on socket comes through. f==read || f==vwrite
   */
  size_t
  atomicio6(ssize_t (*f) (int, void *, size_t), int fd, void *_s, size_t n,
      int (*cb)(void *, size_t), void *cb_arg)
  {
  	char *s = _s;
  	size_t pos = 0;
  	ssize_t res;
  	struct pollfd pfd;
  
  	pfd.fd = fd;
  	pfd.events = f == read ? POLLIN : POLLOUT;
  	while (n > pos) {
  		res = (f) (fd, s + pos, n - pos);
  		switch (res) {
  		case -1:
  			if (errno == EINTR) {
  				/* possible SIGALARM, update callback */
  				if (cb != NULL && cb(cb_arg, 0) == -1) {
  					errno = EINTR;
  					return pos;
  				}
  				continue;
  			} else if (errno == EAGAIN || errno == EWOULDBLOCK) {
  				(void)poll(&pfd, 1, -1);
  				continue;
  			}
  			return 0;
  		case 0:
  			errno = EPIPE;
  			return pos;
  		default:
  			pos += (size_t)res;
  			if (cb != NULL && cb(cb_arg, (size_t)res) == -1) {
  				errno = EINTR;
  				return pos;
  			}
  		}
  	}
  	return pos;
  }
  
  size_t
  atomicio(ssize_t (*f) (int, void *, size_t), int fd, void *_s, size_t n)
  {
  	return atomicio6(f, fd, _s, n, NULL, NULL);
  }
  
  /*
   * ensure all of data on socket comes through. f==readv || f==writev
   */
  size_t
  atomiciov6(ssize_t (*f) (int, const struct iovec *, int), int fd,
      const struct iovec *_iov, int iovcnt,
      int (*cb)(void *, size_t), void *cb_arg)
  {
  	size_t pos = 0, rem;
  	ssize_t res;
  	struct iovec iov_array[IOV_MAX], *iov = iov_array;
  	struct pollfd pfd;
  
  	if (iovcnt < 0 || iovcnt > IOV_MAX) {
  		errno = EINVAL;
  		return 0;
  	}
  	/* Make a copy of the iov array because we may modify it below */
  	memcpy(iov, _iov, (size_t)iovcnt * sizeof(*_iov));
  
  	pfd.fd = fd;
  	pfd.events = f == readv ? POLLIN : POLLOUT;
  	for (; iovcnt > 0 && iov[0].iov_len > 0;) {
  		res = (f) (fd, iov, iovcnt);
  		switch (res) {
  		case -1:
  			if (errno == EINTR) {
  				/* possible SIGALARM, update callback */
  				if (cb != NULL && cb(cb_arg, 0) == -1) {
  					errno = EINTR;
  					return pos;
  				}
  				continue;
  			} else if (errno == EAGAIN || errno == EWOULDBLOCK) {
  				(void)poll(&pfd, 1, -1);
  				continue;
  			}
  			return 0;
  		case 0:
  			errno = EPIPE;
  			return pos;
  		default:
  			rem = (size_t)res;
  			pos += rem;
  			/* skip completed iov entries */
  			while (iovcnt > 0 && rem >= iov[0].iov_len) {
  				rem -= iov[0].iov_len;
  				iov++;
  				iovcnt--;
  			}
  			/* This shouldn't happen... */
  			if (rem > 0 && (iovcnt <= 0 || rem > iov[0].iov_len)) {
  				errno = EFAULT;
  				return 0;
  			}
  			if (iovcnt == 0)
  				break;
  			/* update pointer in partially complete iov */
  			iov[0].iov_base = ((char *)iov[0].iov_base) + rem;
  			iov[0].iov_len -= rem;
  		}
  		if (cb != NULL && cb(cb_arg, (size_t)res) == -1) {
  			errno = EINTR;
  			return pos;
  		}
  	}
  	return pos;
  }
  
  size_t
  atomiciov(ssize_t (*f) (int, const struct iovec *, int), int fd,
      const struct iovec *_iov, int iovcnt)
  {
  	return atomiciov6(f, fd, _iov, iovcnt, NULL, NULL);
  }