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Diffstat (limited to 'source3/lib/recvfile.c')
| -rw-r--r-- | source3/lib/recvfile.c | 233 |
1 files changed, 233 insertions, 0 deletions
diff --git a/source3/lib/recvfile.c b/source3/lib/recvfile.c new file mode 100644 index 0000000000..513742ce8f --- /dev/null +++ b/source3/lib/recvfile.c @@ -0,0 +1,233 @@ +/* + Unix SMB/Netbios implementation. + Version 3.2.x + recvfile implementations. + Copyright (C) Jeremy Allison 2007. + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 3 of the License, or + (at your option) any later version. + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, see <http://www.gnu.org/licenses/>. +*/ + +/* + * This file handles the OS dependent recvfile implementations. + * The API is such that it returns -1 on error, else returns the + * number of bytes written. + */ + +#include "includes.h" + +/* Do this on our own in TRANSFER_BUF_SIZE chunks. + * It's safe to make direct syscalls to lseek/write here + * as we're below the Samba vfs layer. + * + * If tofd is -1 we just drain the incoming socket of count + * bytes without writing to the outgoing fd. + * If a write fails we do the same (to cope with disk full) + * errors. + * + * Returns -1 on short reads from fromfd (read error) + * and sets errno. + * + * Returns number of bytes written to 'tofd' + * or thrown away if 'tofd == -1'. + * return != count then sets errno. + * Returns count if complete success. + */ + +#ifndef TRANSFER_BUF_SIZE +#define TRANSFER_BUF_SIZE (128*1024) +#endif + +static ssize_t default_sys_recvfile(int fromfd, + int tofd, + SMB_OFF_T offset, + size_t count) +{ + int saved_errno = 0; + size_t total = 0; + size_t bufsize = MIN(TRANSFER_BUF_SIZE,count); + size_t total_written = 0; + char *buffer = NULL; + + DEBUG(10,("default_sys_recvfile: from = %d, to = %d, " + "offset=%.0f, count = %lu\n", + fromfd, tofd, (double)offset, + (unsigned long)count)); + + if (count == 0) { + return 0; + } + + if (tofd != -1 && offset != (SMB_OFF_T)-1) { + if (sys_lseek(tofd, offset, SEEK_SET) == -1) { + if (errno != ESPIPE) { + return -1; + } + } + } + + buffer = SMB_MALLOC_ARRAY(char, bufsize); + if (buffer == NULL) { + return -1; + } + + while (total < count) { + size_t num_written = 0; + ssize_t read_ret; + size_t toread = MIN(bufsize,count - total); + + /* Read from socket - ignore EINTR. */ + read_ret = sys_read(fromfd, buffer, toread); + if (read_ret <= 0) { + /* EOF or socket error. */ + free(buffer); + return -1; + } + + num_written = 0; + + while (num_written < read_ret) { + ssize_t write_ret; + + if (tofd == -1) { + write_ret = read_ret; + } else { + /* Write to file - ignore EINTR. */ + write_ret = sys_write(tofd, + buffer + num_written, + read_ret - num_written); + + if (write_ret <= 0) { + /* write error - stop writing. */ + tofd = -1; + saved_errno = errno; + continue; + } + } + + num_written += (size_t)write_ret; + total_written += (size_t)write_ret; + } + + total += read_ret; + } + + free(buffer); + if (saved_errno) { + /* Return the correct write error. */ + errno = saved_errno; + } + return (ssize_t)total_written; +} + +#if defined(HAVE_LINUX_SPLICE) + +/* + * Try and use the Linux system call to do this. + * Remember we only return -1 if the socket read + * failed. Else we return the number of bytes + * actually written. We always read count bytes + * from the network in the case of return != -1. + */ + + +ssize_t sys_recvfile(int fromfd, + int tofd, + SMB_OFF_T offset, + size_t count) +{ + static bool try_splice_call = true; + size_t total_written = 0; + + DEBUG(10,("sys_recvfile: from = %d, to = %d, " + "offset=%.0f, count = %lu\n", + fromfd, tofd, (double)offset, + (unsigned long)count)); + + if (count == 0) { + return 0; + } + + /* + * Older Linux kernels have splice for sendfile, + * but it fails for recvfile. Ensure we only try + * this once and always fall back to the userspace + * implementation if recvfile splice fails. JRA. + */ + + if (!try_splice_call) { + return default_sys_recvfile(fromfd, + tofd, + offset, + count); + } + + while (total_written < count) { + ssize_t ret = splice(fromfd, + NULL, + tofd, + &offset, + count, + 0); + if (ret == -1) { + if (errno != EINTR) { + if (total_written == 0 && + (errno == EBADF || errno == EINVAL)) { + try_splice_call = false; + return default_sys_recvfile(fromfd, + tofd, + offset, + count); + } + break; + } + continue; + } + total_written += ret; + count -= ret; + } + + if (total_written < count) { + int saved_errno = errno; + if (drain_socket(fromfd, count-total_written) != + count-total_written) { + /* socket is dead. */ + return -1; + } + errno = saved_errno; + } + + return total_written; +} +#else + +/***************************************************************** + No recvfile system call - use the default 128 chunk implementation. +*****************************************************************/ + +ssize_t sys_recvfile(int fromfd, + int tofd, + SMB_OFF_T offset, + size_t count) +{ + return default_sys_recvfile(fromfd, tofd, offset, count); +} +#endif + +/***************************************************************** + Throw away "count" bytes from the client socket. +*****************************************************************/ + +ssize_t drain_socket(int sockfd, size_t count) +{ + return default_sys_recvfile(sockfd, -1, (SMB_OFF_T)-1, count); +} |