222 lines
8.5 KiB
C
222 lines
8.5 KiB
C
/*
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* Buffered Read. This file is part of Shairport Sync
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* Copyright (c) Mike Brady 2025
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* Modifications, including those associated with audio synchronization, multithreading and
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* metadata handling copyright (c) Mike Brady 2014--2025
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* All rights reserved.
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*
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* Permission is hereby granted, free of charge, to any person
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* obtaining a copy of this software and associated documentation
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* files (the "Software"), to deal in the Software without
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* restriction, including without limitation the rights to use,
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* copy, modify, merge, publish, distribute, sublicense, and/or
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* sell copies of the Software, and to permit persons to whom the
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* Software is furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be
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* included in all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
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* OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
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* HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
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* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
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* OTHER DEALINGS IN THE SOFTWARE.
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*/
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#include <sys/types.h>
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#include "buffered_read.h"
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#include "common.h"
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ssize_t buffered_read(buffered_tcp_desc *descriptor, void *buf, size_t count,
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size_t *bytes_remaining) {
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ssize_t response = -1;
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if (debug_mutex_lock(&descriptor->mutex, 50000, 1) != 0)
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debug(1, "problem with mutex");
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pthread_cleanup_push(mutex_unlock, (void *)&descriptor->mutex);
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// wipe the slate dlean before reading...
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descriptor->error_code = 0;
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descriptor->closed = 0;
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if (descriptor->buffer_occupancy == 0) {
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debug(2, "buffered_read: buffer empty -- waiting for %zu bytes.", count);
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}
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while ((descriptor->buffer_occupancy == 0) && (descriptor->error_code == 0) &&
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(descriptor->closed == 0)) {
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if (pthread_cond_wait(&descriptor->not_empty_cv, &descriptor->mutex))
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debug(1, "Error waiting for buffered read");
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else
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debug(2, "buffered_read: signalled with %zu bytes after waiting.",
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descriptor->buffer_occupancy);
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}
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if (descriptor->error_code) {
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errno = descriptor->error_code;
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debug(1, "buffered_read: error %d.", errno);
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response = -1;
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} else if (descriptor->closed != 0) {
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debug(2, "buffered_read: connection closed.");
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errno = 0; // no error -- just closed
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response = 0;
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} else if (descriptor->buffer_occupancy != 0) {
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ssize_t bytes_to_move = count;
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if (descriptor->buffer_occupancy < count) {
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bytes_to_move = descriptor->buffer_occupancy;
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}
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ssize_t top_gap = descriptor->buffer + descriptor->buffer_max_size - descriptor->toq;
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if (top_gap < bytes_to_move)
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bytes_to_move = top_gap;
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memcpy(buf, descriptor->toq, bytes_to_move);
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descriptor->toq += bytes_to_move;
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if (descriptor->toq == descriptor->buffer + descriptor->buffer_max_size)
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descriptor->toq = descriptor->buffer;
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descriptor->buffer_occupancy -= bytes_to_move;
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if (bytes_remaining != NULL)
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*bytes_remaining = descriptor->buffer_occupancy;
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response = bytes_to_move;
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if (pthread_cond_signal(&descriptor->not_full_cv))
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debug(1, "Error signalling");
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}
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pthread_cleanup_pop(1); // release the mutex
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return response;
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}
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#define STANDARD_PACKET_SIZE 4096
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void buffered_tcp_reader_cleanup_handler(__attribute__((unused)) void *arg) {
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debug(2, "Buffered TCP Reader Thread Exit via Cleanup.");
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}
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void *buffered_tcp_reader(void *arg) {
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// #include <syscall.h>
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// debug(1, "buffered_tcp_reader PID %d", syscall(SYS_gettid));
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pthread_cleanup_push(buffered_tcp_reader_cleanup_handler, NULL);
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buffered_tcp_desc *descriptor = (buffered_tcp_desc *)arg;
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// listen(descriptor->sock_fd, 5); // this is done in the handle_setup_2 code to ensure it's open
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// when the client hears about it...
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ssize_t nread;
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SOCKADDR remote_addr;
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memset(&remote_addr, 0, sizeof(remote_addr));
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socklen_t addr_size = sizeof(remote_addr);
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int finished = 0;
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int fd = accept(descriptor->sock_fd, (struct sockaddr *)&remote_addr, &addr_size);
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// debug(1, "buffered_tcp_reader: the client has opened a buffered audio link.");
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intptr_t pfd = fd;
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pthread_cleanup_push(socket_cleanup, (void *)pfd);
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do {
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int have_time_to_sleep = 0;
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if (debug_mutex_lock(&descriptor->mutex, 500000, 1) != 0)
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debug(1, "problem with mutex");
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pthread_cleanup_push(mutex_unlock, (void *)&descriptor->mutex);
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while (descriptor->buffer_occupancy == descriptor->buffer_max_size) {
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if (pthread_cond_wait(&descriptor->not_full_cv, &descriptor->mutex))
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debug(1, "Error waiting for not_full_cv");
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}
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pthread_cleanup_pop(1); // release the mutex
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// now we know it is not full, so go ahead and try to read some more into it
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// wrap
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if ((size_t)(descriptor->eoq - descriptor->buffer) == descriptor->buffer_max_size)
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descriptor->eoq = descriptor->buffer;
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// figure out how much to ask for
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size_t bytes_to_request = STANDARD_PACKET_SIZE;
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size_t free_space = descriptor->buffer_max_size - descriptor->buffer_occupancy;
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if (bytes_to_request > free_space)
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bytes_to_request = free_space; // don't ask for more than will fit
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size_t gap_to_end_of_buffer =
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descriptor->buffer + descriptor->buffer_max_size - descriptor->eoq;
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if (gap_to_end_of_buffer < bytes_to_request)
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bytes_to_request =
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gap_to_end_of_buffer; // only ask for what will fill to the top of the buffer
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// do the read
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if (descriptor->buffer_occupancy == 0)
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debug(2, "recv of up to %zd bytes with an buffer empty.", bytes_to_request);
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nread = recv(fd, descriptor->eoq, bytes_to_request, 0);
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// debug(1, "Received %d bytes for a buffer size of %d bytes.",nread,
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// descriptor->buffer_occupancy + nread);
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if (debug_mutex_lock(&descriptor->mutex, 50000, 1) != 0)
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debug(1, "problem with not empty mutex");
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pthread_cleanup_push(mutex_unlock, (void *)&descriptor->mutex);
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if (nread < 0) {
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char errorstring[1024];
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strerror_r(errno, (char *)errorstring, sizeof(errorstring));
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debug(1, "error in buffered_tcp_reader %d: \"%s\". Could not recv a packet.", errno,
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errorstring);
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descriptor->error_code = errno;
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} else if (nread == 0) {
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descriptor->closed = 1;
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debug(
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2,
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"buffered audio port closed by remote end. Terminating the buffered_tcp_reader thread.");
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finished = 1;
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} else if (nread > 0) {
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descriptor->eoq += nread;
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descriptor->buffer_occupancy += nread;
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}
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// signal if we got data or an error or the file closed
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if (pthread_cond_signal(&descriptor->not_empty_cv))
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debug(1, "Error signalling");
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if (descriptor->buffer_occupancy > 16384)
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have_time_to_sleep = 1;
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pthread_cleanup_pop(1); // release the mutex
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if (have_time_to_sleep)
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usleep(10000); // give other threads a chance to run...
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} while (finished == 0);
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debug(2, "Buffered TCP Reader Thread Exit \"Normal\" Exit Begin.");
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pthread_cleanup_pop(1); // close the socket
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pthread_cleanup_pop(1); // cleanup
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debug(2, "Buffered TCP Reader Thread Exit \"Normal\" Exit.");
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pthread_exit(NULL);
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}
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// this will read a block of the size specified to the buffer
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// and will return either with the block or on error
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ssize_t read_sized_block(buffered_tcp_desc *descriptor, void *buf, size_t count,
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size_t *bytes_remaining) {
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ssize_t response, nread;
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size_t inbuf = 0; // bytes already in the buffer
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int keep_trying = 1;
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do {
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nread = buffered_read(descriptor, buf + inbuf, count - inbuf, bytes_remaining);
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if (nread == 0) {
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// a blocking read that returns zero means eof -- implies connection closed
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debug(2, "read_sized_block connection closed.");
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keep_trying = 0;
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} else if (nread < 0) {
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if (errno == EAGAIN) {
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debug(1, "read_sized_block getting Error 11 -- EAGAIN from a blocking read!");
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}
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if ((errno != EAGAIN) && (errno != EINTR)) {
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char errorstring[1024];
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strerror_r(errno, (char *)errorstring, sizeof(errorstring));
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debug(1, "read_sized_block read error %d: \"%s\".", errno, (char *)errorstring);
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keep_trying = 0;
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}
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} else {
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inbuf += (size_t)nread;
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}
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} while ((keep_trying != 0) && (inbuf < count));
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if (nread <= 0)
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response = nread;
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else
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response = inbuf;
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return response;
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}
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