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@ -143,98 +143,176 @@ ring_buffer_push (ring_buffer *ring, int fd) |
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return r; |
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} |
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/* PULL PUMP
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* |
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* This is used to read data from a blocking file descriptor and pump it into |
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* a non-blocking pipe (or other non-blocking fd). The algorithm is this: |
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* |
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* while (true) { |
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* read(STDIN_FILENO) // blocking
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* |
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* while (!ring.empty) { |
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* write(pipe) // non-blocking
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* select(pipe, writable) |
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* } |
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* } |
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* |
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*/ |
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static void |
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pump (int is_pull, int pullfd, int pushfd) |
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pull_pump (int pullfd, int pushfd) |
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{ |
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int r; |
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ring_buffer ring; |
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fd_set readfds, writefds, exceptfds; |
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fd_set writefds, exceptfds; |
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FD_ZERO(&exceptfds); |
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FD_ZERO(&writefds); |
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FD_SET(pushfd, &exceptfds); |
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FD_SET(pushfd, &writefds); |
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ring_buffer_init(&ring); |
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int maxfd; |
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while (pullfd >= 0) { |
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/* Blocking read from STDIN_FILENO */ |
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r = ring_buffer_pull(&ring, pullfd); |
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while (pushfd >= 0 && (pullfd >= 0 || !ring_buffer_empty_p(&ring))) { |
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FD_ZERO(&exceptfds); |
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FD_ZERO(&readfds); |
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FD_ZERO(&writefds); |
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maxfd = -1; |
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if (is_pull) { |
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if (!ring_buffer_empty_p(&ring)) { |
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maxfd = pushfd; |
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FD_SET(pushfd, &exceptfds); |
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FD_SET(pushfd, &writefds); |
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} |
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} else { |
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if (pullfd >= 0) { |
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if (!ring_buffer_filled_p(&ring)) { |
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maxfd = pullfd; |
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FD_SET(pullfd, &exceptfds); |
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FD_SET(pullfd, &readfds); |
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if (r == 0) { |
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/* eof */ |
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close(pullfd); |
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pullfd = -1; |
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} else if (r < 0 && errno != EINTR && errno != EAGAIN) { |
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/* error */ |
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perror("pull_pump read()"); |
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close(pullfd); |
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pullfd = -1; |
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} |
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/* Push all of the data in the ring buffer out. */ |
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while (!ring_buffer_empty_p(&ring)) { |
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/* non-blocking write() to the pipe */ |
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r = ring_buffer_push(&ring, pushfd); |
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if (r < 0 && errno != EAGAIN && errno != EINTR) { |
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if (errno == EPIPE) { |
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/* This happens if someone closes the other end of the pipe. This
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* is a normal forced close of STDIN. Hopefully there wasn't data |
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* in the ring buffer. Just close both ends and exit. |
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*/ |
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close(pushfd); |
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close(pullfd); |
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pushfd = pullfd = -1; |
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} else { |
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perror("pull_pump write()"); |
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close(pushfd); |
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close(pullfd); |
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} |
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return; |
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} |
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} |
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if (maxfd >= 0) { |
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r = select(maxfd+1, &readfds, &writefds, &exceptfds, NULL); |
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/* Select for writablity on the pipe end.
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* Very rarely will this stick. |
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*/ |
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r = select(pushfd+1, NULL, &writefds, &exceptfds, NULL); |
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if (r < 0 || (pullfd >= 0 && FD_ISSET(pushfd, &exceptfds))) { |
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if (r < 0 || FD_ISSET(pushfd, &exceptfds)) { |
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close(pushfd); |
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close(pullfd); |
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pushfd = pullfd = -1; |
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return; |
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} |
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} |
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} |
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assert(pullfd < 0); |
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assert(ring_buffer_empty_p(&ring)); |
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close(pushfd); |
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} |
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/* PUSH PUMP
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* |
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* This is used to push data out to a blocking file descriptor. It pulls |
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* data from a non-blocking pipe (pullfd) and pushes to STDOUT_FILENO |
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* (pushfd). |
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* When the pipe is closed, then the rest of the data is pushed out and then |
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* STDOUT_FILENO is closed. |
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* |
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* The algorithm looks roughly like this: |
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* |
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* while (true) { |
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* r = read(pipe) // nonblocking
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* |
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* while (!ring.empty) { |
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* write(STDOUT_FILENO) // blocking
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* } |
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* |
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* select(pipe, readable); |
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* } |
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*/ |
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static void |
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push_pump (int pullfd, int pushfd) |
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{ |
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int r; |
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ring_buffer ring; |
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fd_set readfds, exceptfds; |
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FD_ZERO(&exceptfds); |
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FD_ZERO(&readfds); |
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FD_SET(pullfd, &exceptfds); |
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FD_SET(pullfd, &readfds); |
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ring_buffer_init(&ring); |
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/* The pipe is open or there is data left to be pushed out
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* NOTE: if pushfd (STDOUT_FILENO) ever errors out, then we just exit the |
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* loop. |
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*/ |
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while (pullfd >= 0 || !ring_buffer_empty_p(&ring)) { |
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if (pullfd >= 0 && FD_ISSET(pullfd, &exceptfds)) { |
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/* Pull from the non-blocking pipe */ |
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r = ring_buffer_pull(&ring, pullfd); |
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if (r == 0) { |
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/* eof */ |
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close(pullfd); |
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pullfd = -1; |
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} else if (r < 0 && errno != EINTR && errno != EAGAIN) { |
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perror("push_pump read()"); |
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close(pullfd); |
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pullfd = -1; |
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return; |
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} |
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if (pullfd >= 0 && (is_pull || FD_ISSET(pullfd, &readfds))) { |
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r = ring_buffer_pull(&ring, pullfd); |
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if (r == 0) { |
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/* eof */ |
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close(pullfd); |
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pullfd = -1; |
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/* Push everything out to STDOUT */ |
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while (!ring_buffer_empty_p(&ring)) { |
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/* Blocking write() to pushfd (STDOUT_FILENO) */ |
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r = ring_buffer_push(&ring, pushfd); |
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/* If there was a problem, just exit the entire function */ |
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} else if (r < 0) { |
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if (errno != EINTR && errno != EAGAIN) goto error; |
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if (r < 0 && errno != EINTR) { |
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close(pushfd); |
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close(pullfd); |
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pushfd = pullfd = -1; |
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return; |
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} |
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} |
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if (pullfd >= 0) { |
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/* select for readability on the pullfd */ |
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r = select(pullfd+1, &readfds, NULL, &exceptfds, NULL); |
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if (!is_pull || FD_ISSET(pushfd, &writefds)) { |
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r = ring_buffer_push(&ring, pushfd); |
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if (r < 0) { |
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switch (errno) { |
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case EINTR: |
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case EAGAIN: |
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continue; |
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case EPIPE: |
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/* TODO catch SIGPIPE? */ |
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close(pushfd); |
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close(pullfd); |
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pushfd = pullfd = -1; |
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return; |
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default: |
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goto error; |
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} |
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if (r < 0 || FD_ISSET(pullfd, &exceptfds)) { |
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close(pushfd); |
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close(pullfd); |
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pushfd = pullfd = -1; |
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return; |
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} |
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} |
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} |
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/* If we got here then we got eof on pullfd and pushed all the data out.
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* so now just close pushfd */ |
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assert(pullfd < 0); |
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assert(ring_buffer_empty_p(&ring)); |
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close(pushfd); |
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close(pullfd); |
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return; |
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error: |
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close(pushfd); |
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close(pullfd); |
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perror("(coupling) pump"); |
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} |
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static inline int |
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@ -262,7 +340,11 @@ pump_thread (void *data) |
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{ |
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struct coupling *c = (struct coupling*)data; |
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pump(c->is_pull, c->pullfd, c->pushfd); |
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if (c->is_pull) { |
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pull_pump(c->pullfd, c->pushfd); |
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} else { |
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push_pump(c->pullfd, c->pushfd); |
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} |
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return NULL; |
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} |
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