118 lines
2.8 KiB
C
118 lines
2.8 KiB
C
#include <poll.h>
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#include <sys/timerfd.h>
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#include <time.h>
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#include <stdio.h>
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#include <string.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <fcntl.h>
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#include <error.h>
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#include <signal.h>
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#include <sys/socket.h>
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#include <sys/un.h>
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#include <errno.h>
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int open_shipper_socket(char *pathname) {
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int fd;
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struct sockaddr_un sa = {
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.sun_family = AF_LOCAL
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};
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strncpy(sa.sun_path, pathname, sizeof(sa.sun_path) - 1);
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fd = socket(AF_LOCAL, SOCK_STREAM, 0);
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if(fd >= 0) {
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if(connect(fd, (struct sockaddr *) &sa, sizeof sa)) {
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error(0, errno, "connect socket \"%s\"", pathname);
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return -1;
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}
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int flags = fcntl(fd, F_GETFL);
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fcntl(fd, F_SETFL, flags | O_NONBLOCK);
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}
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return fd;
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}
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struct pollfd fds[] = {
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{ .fd = 0, .events = POLLIN },
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{ .fd = 1, .events = POLLERR },
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{ .fd = -1, .events = POLLERR },
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};
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int is_connected(void) {
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return (fds[2].fd >= 0);
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}
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int main(int argc, char * argv[]) {
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char * buf = malloc(8192);
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int out_bytes = 0;
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int tee_bytes = 0;
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if(argc != 3) {
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error(1, 0, "usage: logtee /path/to/socket cookie-text");
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}
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char * socket_pathname = argv[1];
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char * cookie = argv[2];
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char * start_cookie = malloc(strlen(cookie) + 8);
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char * stop_cookie = malloc(strlen(cookie) + 7);
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if(strlen(socket_pathname) > 108) {
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error(1, 0, "socket pathname \"%s\" is too long, max 108 bytes",
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socket_pathname);
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};
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strcpy(start_cookie, cookie); strcat(start_cookie, " START\n");
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strcpy(stop_cookie, cookie); strcat(stop_cookie, " STOP\n");
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signal(SIGPIPE, SIG_IGN);
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int flags = fcntl(STDOUT_FILENO, F_GETFL);
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fcntl(STDOUT_FILENO, F_SETFL, flags | O_NONBLOCK);
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int quitting = 0;
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while(! quitting) {
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int nfds = poll(fds, 3, 2000);
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if(nfds > 0) {
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if((fds[0].revents & (POLLIN|POLLHUP)) &&
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(out_bytes == 0) &&
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(tee_bytes == 0)) {
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out_bytes = read(fds[0].fd, buf, 8192);
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if(out_bytes == 0) {
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quitting = 1;
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buf = "logtee detected eof of file on stdin, exiting\n";
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out_bytes = strlen(buf);
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};
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if(is_connected()) tee_bytes = out_bytes;
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};
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if(out_bytes) {
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out_bytes -= write(fds[1].fd, buf, out_bytes);
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};
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if(fds[1].revents & (POLLERR|POLLHUP)) {
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exit(1); // can't even log an error if the logging stream fails
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};
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if(is_connected()) {
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if(tee_bytes) {
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tee_bytes -= write(fds[2].fd, buf, tee_bytes);
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};
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if(fds[2].revents & (POLLERR|POLLHUP)) {
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close(fds[2].fd);
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fds[2].fd = -1;
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(void) write(1, stop_cookie, strlen(stop_cookie));
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};
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};
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} else {
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if(! is_connected()) {
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fds[2].fd = open_shipper_socket(argv[1]);
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if(is_connected()) {
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/* write cookie to stdout so that the backfill
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* process knows we are now logging realtime
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*/
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write(fds[1].fd, start_cookie, strlen(start_cookie));
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}
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}
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};
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};
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}
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