diff options
Diffstat (limited to 'src/bridge.c')
-rw-r--r-- | src/bridge.c | 367 |
1 files changed, 367 insertions, 0 deletions
diff --git a/src/bridge.c b/src/bridge.c new file mode 100644 index 0000000000..bfb38a8bb4 --- /dev/null +++ b/src/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 General Public License as published by + the Free Software Foundation; either version 2 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 + General Public License for more details. + + You should have received a copy of the GNU 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; +} |