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-rw-r--r--src/stdio-bridge/stdio-bridge.c367
1 files changed, 367 insertions, 0 deletions
diff --git a/src/stdio-bridge/stdio-bridge.c b/src/stdio-bridge/stdio-bridge.c
new file mode 100644
index 0000000000..f926fe5538
--- /dev/null
+++ b/src/stdio-bridge/stdio-bridge.c
@@ -0,0 +1,367 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+/***
+ This file is part of systemd.
+
+ Copyright 2010 Lennart Poettering
+
+ systemd is free software; you can redistribute it and/or modify it
+ under the terms of the GNU Lesser General Public License as published by
+ the Free Software Foundation; either version 2.1 of the License, or
+ (at your option) any later version.
+
+ systemd 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
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public License
+ along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <sys/socket.h>
+#include <sys/un.h>
+#include <sys/types.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <string.h>
+#include <errno.h>
+#include <sys/epoll.h>
+#include <stddef.h>
+
+#include "log.h"
+#include "util.h"
+#include "socket-util.h"
+
+#define BUFFER_SIZE (64*1024)
+#define EXTRA_SIZE 16
+
+static bool initial_nul = false;
+static bool auth_over = false;
+
+static void format_uid(char *buf, size_t l) {
+ char text[20 + 1]; /* enough space for a 64bit integer plus NUL */
+ unsigned j;
+
+ assert(l > 0);
+
+ snprintf(text, sizeof(text)-1, "%llu", (unsigned long long) geteuid());
+ text[sizeof(text)-1] = 0;
+
+ memset(buf, 0, l);
+
+ for (j = 0; text[j] && j*2+2 < l; j++) {
+ buf[j*2] = hexchar(text[j] >> 4);
+ buf[j*2+1] = hexchar(text[j] & 0xF);
+ }
+
+ buf[j*2] = 0;
+}
+
+static size_t patch_in_line(char *line, size_t l, size_t left) {
+ size_t r;
+
+ if (line[0] == 0 && !initial_nul) {
+ initial_nul = true;
+ line += 1;
+ l -= 1;
+ r = 1;
+ } else
+ r = 0;
+
+ if (l == 5 && strncmp(line, "BEGIN", 5) == 0) {
+ r += l;
+ auth_over = true;
+
+ } else if (l == 17 && strncmp(line, "NEGOTIATE_UNIX_FD", 17) == 0) {
+ memmove(line + 13, line + 17, left);
+ memcpy(line, "NEGOTIATE_NOP", 13);
+ r += 13;
+
+ } else if (l >= 14 && strncmp(line, "AUTH EXTERNAL ", 14) == 0) {
+ char uid[20*2 + 1];
+ size_t len;
+
+ format_uid(uid, sizeof(uid));
+ len = strlen(uid);
+ assert(len <= EXTRA_SIZE);
+
+ memmove(line + 14 + len, line + l, left);
+ memcpy(line + 14, uid, len);
+
+ r += 14 + len;
+ } else
+ r += l;
+
+ return r;
+}
+
+static size_t patch_in_buffer(char* in_buffer, size_t *in_buffer_full) {
+ size_t i, good = 0;
+
+ if (*in_buffer_full <= 0)
+ return *in_buffer_full;
+
+ /* If authentication is done, we don't touch anything anymore */
+ if (auth_over)
+ return *in_buffer_full;
+
+ if (*in_buffer_full < 2)
+ return 0;
+
+ for (i = 0; i <= *in_buffer_full - 2; i ++) {
+
+ /* Fully lines can be send on */
+ if (in_buffer[i] == '\r' && in_buffer[i+1] == '\n') {
+ if (i > good) {
+ size_t old_length, new_length;
+
+ old_length = i - good;
+ new_length = patch_in_line(in_buffer+good, old_length, *in_buffer_full - i);
+ *in_buffer_full = *in_buffer_full + new_length - old_length;
+
+ good += new_length + 2;
+
+ } else
+ good = i+2;
+ }
+
+ if (auth_over)
+ break;
+ }
+
+ return good;
+}
+
+int main(int argc, char *argv[]) {
+ int r = EXIT_FAILURE, fd = -1, ep = -1;
+ union sockaddr_union sa;
+ char in_buffer[BUFFER_SIZE+EXTRA_SIZE], out_buffer[BUFFER_SIZE+EXTRA_SIZE];
+ size_t in_buffer_full = 0, out_buffer_full = 0;
+ struct epoll_event stdin_ev, stdout_ev, fd_ev;
+ bool stdin_readable = false, stdout_writable = false, fd_readable = false, fd_writable = false;
+ bool stdin_rhup = false, stdout_whup = false, fd_rhup = false, fd_whup = false;
+
+ if (argc > 1) {
+ log_error("This program takes no argument.");
+ return EXIT_FAILURE;
+ }
+
+ log_set_target(LOG_TARGET_JOURNAL_OR_KMSG);
+ log_parse_environment();
+ log_open();
+
+ if ((fd = socket(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0)) < 0) {
+ log_error("Failed to create socket: %s", strerror(errno));
+ goto finish;
+ }
+
+ zero(sa);
+ sa.un.sun_family = AF_UNIX;
+ strncpy(sa.un.sun_path, "/run/dbus/system_bus_socket", sizeof(sa.un.sun_path));
+
+ if (connect(fd, &sa.sa, offsetof(struct sockaddr_un, sun_path) + strlen(sa.un.sun_path)) < 0) {
+ log_error("Failed to connect: %m");
+ goto finish;
+ }
+
+ fd_nonblock(STDIN_FILENO, 1);
+ fd_nonblock(STDOUT_FILENO, 1);
+
+ if ((ep = epoll_create1(EPOLL_CLOEXEC)) < 0) {
+ log_error("Failed to create epoll: %m");
+ goto finish;
+ }
+
+ zero(stdin_ev);
+ stdin_ev.events = EPOLLIN|EPOLLET;
+ stdin_ev.data.fd = STDIN_FILENO;
+
+ zero(stdout_ev);
+ stdout_ev.events = EPOLLOUT|EPOLLET;
+ stdout_ev.data.fd = STDOUT_FILENO;
+
+ zero(fd_ev);
+ fd_ev.events = EPOLLIN|EPOLLOUT|EPOLLET;
+ fd_ev.data.fd = fd;
+
+ if (epoll_ctl(ep, EPOLL_CTL_ADD, STDIN_FILENO, &stdin_ev) < 0 ||
+ epoll_ctl(ep, EPOLL_CTL_ADD, STDOUT_FILENO, &stdout_ev) < 0 ||
+ epoll_ctl(ep, EPOLL_CTL_ADD, fd, &fd_ev) < 0) {
+ log_error("Failed to regiser fds in epoll: %m");
+ goto finish;
+ }
+
+ do {
+ struct epoll_event ev[16];
+ ssize_t k;
+ int i, nfds;
+
+ if ((nfds = epoll_wait(ep, ev, ELEMENTSOF(ev), -1)) < 0) {
+
+ if (errno == EINTR || errno == EAGAIN)
+ continue;
+
+ log_error("epoll_wait(): %m");
+ goto finish;
+ }
+
+ assert(nfds >= 1);
+
+ for (i = 0; i < nfds; i++) {
+ if (ev[i].data.fd == STDIN_FILENO) {
+
+ if (!stdin_rhup && (ev[i].events & (EPOLLHUP|EPOLLIN)))
+ stdin_readable = true;
+
+ } else if (ev[i].data.fd == STDOUT_FILENO) {
+
+ if (ev[i].events & EPOLLHUP) {
+ stdout_writable = false;
+ stdout_whup = true;
+ }
+
+ if (!stdout_whup && (ev[i].events & EPOLLOUT))
+ stdout_writable = true;
+
+ } else if (ev[i].data.fd == fd) {
+
+ if (ev[i].events & EPOLLHUP) {
+ fd_writable = false;
+ fd_whup = true;
+ }
+
+ if (!fd_rhup && (ev[i].events & (EPOLLHUP|EPOLLIN)))
+ fd_readable = true;
+
+ if (!fd_whup && (ev[i].events & EPOLLOUT))
+ fd_writable = true;
+ }
+ }
+
+ while ((stdin_readable && in_buffer_full <= 0) ||
+ (fd_writable && patch_in_buffer(in_buffer, &in_buffer_full) > 0) ||
+ (fd_readable && out_buffer_full <= 0) ||
+ (stdout_writable && out_buffer_full > 0)) {
+
+ size_t in_buffer_good = 0;
+
+ if (stdin_readable && in_buffer_full < BUFFER_SIZE) {
+
+ if ((k = read(STDIN_FILENO, in_buffer + in_buffer_full, BUFFER_SIZE - in_buffer_full)) < 0) {
+
+ if (errno == EAGAIN)
+ stdin_readable = false;
+ else if (errno == EPIPE || errno == ECONNRESET)
+ k = 0;
+ else {
+ log_error("read(): %m");
+ goto finish;
+ }
+ } else
+ in_buffer_full += (size_t) k;
+
+ if (k == 0) {
+ stdin_rhup = true;
+ stdin_readable = false;
+ shutdown(STDIN_FILENO, SHUT_RD);
+ close_nointr_nofail(STDIN_FILENO);
+ }
+ }
+
+ in_buffer_good = patch_in_buffer(in_buffer, &in_buffer_full);
+
+ if (fd_writable && in_buffer_good > 0) {
+
+ if ((k = write(fd, in_buffer, in_buffer_good)) < 0) {
+
+ if (errno == EAGAIN)
+ fd_writable = false;
+ else if (errno == EPIPE || errno == ECONNRESET) {
+ fd_whup = true;
+ fd_writable = false;
+ shutdown(fd, SHUT_WR);
+ } else {
+ log_error("write(): %m");
+ goto finish;
+ }
+
+ } else {
+ assert(in_buffer_full >= (size_t) k);
+ memmove(in_buffer, in_buffer + k, in_buffer_full - k);
+ in_buffer_full -= k;
+ }
+ }
+
+ if (fd_readable && out_buffer_full < BUFFER_SIZE) {
+
+ if ((k = read(fd, out_buffer + out_buffer_full, BUFFER_SIZE - out_buffer_full)) < 0) {
+
+ if (errno == EAGAIN)
+ fd_readable = false;
+ else if (errno == EPIPE || errno == ECONNRESET)
+ k = 0;
+ else {
+ log_error("read(): %m");
+ goto finish;
+ }
+ } else
+ out_buffer_full += (size_t) k;
+
+ if (k == 0) {
+ fd_rhup = true;
+ fd_readable = false;
+ shutdown(fd, SHUT_RD);
+ }
+ }
+
+ if (stdout_writable && out_buffer_full > 0) {
+
+ if ((k = write(STDOUT_FILENO, out_buffer, out_buffer_full)) < 0) {
+
+ if (errno == EAGAIN)
+ stdout_writable = false;
+ else if (errno == EPIPE || errno == ECONNRESET) {
+ stdout_whup = true;
+ stdout_writable = false;
+ shutdown(STDOUT_FILENO, SHUT_WR);
+ close_nointr(STDOUT_FILENO);
+ } else {
+ log_error("write(): %m");
+ goto finish;
+ }
+
+ } else {
+ assert(out_buffer_full >= (size_t) k);
+ memmove(out_buffer, out_buffer + k, out_buffer_full - k);
+ out_buffer_full -= k;
+ }
+ }
+ }
+
+ if (stdin_rhup && in_buffer_full <= 0 && !fd_whup) {
+ fd_whup = true;
+ fd_writable = false;
+ shutdown(fd, SHUT_WR);
+ }
+
+ if (fd_rhup && out_buffer_full <= 0 && !stdout_whup) {
+ stdout_whup = true;
+ stdout_writable = false;
+ shutdown(STDOUT_FILENO, SHUT_WR);
+ close_nointr(STDOUT_FILENO);
+ }
+
+ } while (!stdout_whup || !fd_whup);
+
+ r = EXIT_SUCCESS;
+
+finish:
+ if (fd >= 0)
+ close_nointr_nofail(fd);
+
+ if (ep >= 0)
+ close_nointr_nofail(ep);
+
+ return r;
+}
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