[thirdparty/systemd.git] / src / bridge.c

/*-*- 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_SYSLOG_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, "/var/run/dbus/system_bus_socket", sizeof(sa.un.sun_path));

        if (connect(fd, &sa.sa, offsetof(struct sockaddr_un, sun_path) + 1 + strlen(sa.un.sun_path+1)) < 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;
}
Commit	Line	Data
a8f11321 LP	1	/-- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil --/
	2
	3	/***
	4	This file is part of systemd.
	5
	6	Copyright 2010 Lennart Poettering
	7
	8	systemd is free software; you can redistribute it and/or modify it
	9	under the terms of the GNU General Public License as published by
	10	the Free Software Foundation; either version 2 of the License, or
	11	(at your option) any later version.
	12
	13	systemd is distributed in the hope that it will be useful, but
	14	WITHOUT ANY WARRANTY; without even the implied warranty of
	15	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	16	General Public License for more details.
	17
	18	You should have received a copy of the GNU General Public License
	19	along with systemd; If not, see <http://www.gnu.org/licenses/>.
	20	***/
	21
	22	#include <sys/socket.h>
	23	#include <sys/un.h>
	24	#include <sys/types.h>
	25	#include <fcntl.h>
	26	#include <unistd.h>
	27	#include <string.h>
	28	#include <errno.h>
	29	#include <sys/epoll.h>
	30	#include <stddef.h>
	31
	32	#include "log.h"
	33	#include "util.h"
	34	#include "socket-util.h"
	35
	36	#define BUFFER_SIZE (64*1024)
	37	#define EXTRA_SIZE 16
	38
	39	static bool initial_nul = false;
	40	static bool auth_over = false;
	41
	42	static void format_uid(char *buf, size_t l) {
	43	char text[20 + 1]; /* enough space for a 64bit integer plus NUL */
	44	unsigned j;
	45
	46	assert(l > 0);
	47
	48	snprintf(text, sizeof(text)-1, "%llu", (unsigned long long) geteuid());
	49	text[sizeof(text)-1] = 0;
	50
	51	memset(buf, 0, l);
	52
	53	for (j = 0; text[j] && j*2+2 < l; j++) {
	54	buf[j*2] = hexchar(text[j] >> 4);
	55	buf[j*2+1] = hexchar(text[j] & 0xF);
	56	}
	57
	58	buf[j*2] = 0;
	59	}
	60
	61	static size_t patch_in_line(char *line, size_t l, size_t left) {
	62	size_t r;
	63
	64	if (line[0] == 0 && !initial_nul) {
65	initial_nul = true;
66	line += 1;
67	l -= 1;
68	r = 1;
69	} else
70	r = 0;
71
72	if (l == 5 && strncmp(line, "BEGIN", 5) == 0) {
73	r += l;
74	auth_over = true;
75
76	} else if (l == 17 && strncmp(line, "NEGOTIATE_UNIX_FD", 17) == 0) {
77	memmove(line + 13, line + 17, left);
78	memcpy(line, "NEGOTIATE_NOP", 13);
79	r += 13;
80
81	} else if (l >= 14 && strncmp(line, "AUTH EXTERNAL ", 14) == 0) {
82	char uid[20*2 + 1];
83	size_t len;
84
85	format_uid(uid, sizeof(uid));
86	len = strlen(uid);
87	assert(len <= EXTRA_SIZE);
88
89	memmove(line + 14 + len, line + l, left);
90	memcpy(line + 14, uid, len);
91
92	r += 14 + len;
93	} else
94	r += l;
95
96	return r;
97	}
98
99	static size_t patch_in_buffer(char* in_buffer, size_t *in_buffer_full) {
100	size_t i, good = 0;
101
102	if (*in_buffer_full <= 0)
103	return *in_buffer_full;
104
105	/* If authentication is done, we don't touch anything anymore */
106	if (auth_over)
107	return *in_buffer_full;
108
109	if (*in_buffer_full < 2)
110	return 0;
111
112	for (i = 0; i <= *in_buffer_full - 2; i ++) {
113
114	/* Fully lines can be send on */
115	if (in_buffer[i] == '\r' && in_buffer[i+1] == '\n') {
116	if (i > good) {
117	size_t old_length, new_length;
118
119	old_length = i - good;
120	new_length = patch_in_line(in_buffer+good, old_length, *in_buffer_full - i);
121	in_buffer_full = in_buffer_full + new_length - old_length;
122
123	good += new_length + 2;
124
125	} else
126	good = i+2;
127	}
128
129	if (auth_over)
130	break;
131	}
132
133	return good;
134	}
135
136	int main(int argc, char *argv[]) {
137	int r = EXIT_FAILURE, fd = -1, ep = -1;
138	union sockaddr_union sa;
139	char in_buffer[BUFFER_SIZE+EXTRA_SIZE], out_buffer[BUFFER_SIZE+EXTRA_SIZE];
140	size_t in_buffer_full = 0, out_buffer_full = 0;
141	struct epoll_event stdin_ev, stdout_ev, fd_ev;
142	bool stdin_readable = false, stdout_writable = false, fd_readable = false, fd_writable = false;
143	bool stdin_rhup = false, stdout_whup = false, fd_rhup = false, fd_whup = false;
144
145	if (argc > 1) {
146	log_error("This program takes no argument.");
147	return EXIT_FAILURE;
148	}
149
150	log_set_target(LOG_TARGET_SYSLOG_OR_KMSG);
151	log_parse_environment();
152	log_open();
153
154	if ((fd = socket(AF_UNIX, SOCK_STREAM\|SOCK_CLOEXEC\|SOCK_NONBLOCK, 0)) < 0) {
155	log_error("Failed to create socket: %s", strerror(errno));
156	goto finish;
157	}
158
159	zero(sa);
160	sa.un.sun_family = AF_UNIX;
161	strncpy(sa.un.sun_path, "/var/run/dbus/system_bus_socket", sizeof(sa.un.sun_path));
162
163	if (connect(fd, &sa.sa, offsetof(struct sockaddr_un, sun_path) + 1 + strlen(sa.un.sun_path+1)) < 0) {
164	log_error("Failed to connect: %m");
165	goto finish;
166	}
167
168	fd_nonblock(STDIN_FILENO, 1);
169	fd_nonblock(STDOUT_FILENO, 1);
170
171	if ((ep = epoll_create1(EPOLL_CLOEXEC)) < 0) {
172	log_error("Failed to create epoll: %m");
173	goto finish;
174	}
175
176	zero(stdin_ev);
177	stdin_ev.events = EPOLLIN\|EPOLLET;
178	stdin_ev.data.fd = STDIN_FILENO;
179
180	zero(stdout_ev);
181	stdout_ev.events = EPOLLOUT\|EPOLLET;
182	stdout_ev.data.fd = STDOUT_FILENO;
183
184	zero(fd_ev);
185	fd_ev.events = EPOLLIN\|EPOLLOUT\|EPOLLET;
186	fd_ev.data.fd = fd;
187
188	if (epoll_ctl(ep, EPOLL_CTL_ADD, STDIN_FILENO, &stdin_ev) < 0 \|\|
189	epoll_ctl(ep, EPOLL_CTL_ADD, STDOUT_FILENO, &stdout_ev) < 0 \|\|
190	epoll_ctl(ep, EPOLL_CTL_ADD, fd, &fd_ev) < 0) {
191	log_error("Failed to regiser fds in epoll: %m");
192	goto finish;
193	}
194
195	do {
196	struct epoll_event ev[16];
197	ssize_t k;
198	int i, nfds;
199
200	if ((nfds = epoll_wait(ep, ev, ELEMENTSOF(ev), -1)) < 0) {
201
202	if (errno == EINTR \|\| errno == EAGAIN)
203	continue;
204
205	log_error("epoll_wait(): %m");
206	goto finish;
207	}
208
209	assert(nfds >= 1);
210
211	for (i = 0; i < nfds; i++) {
212	if (ev[i].data.fd == STDIN_FILENO) {
213
214	if (!stdin_rhup && (ev[i].events & (EPOLLHUP\|EPOLLIN)))
215	stdin_readable = true;
216
217	} else if (ev[i].data.fd == STDOUT_FILENO) {
218
219	if (ev[i].events & EPOLLHUP) {
220	stdout_writable = false;
221	stdout_whup = true;
222	}
223
224	if (!stdout_whup && (ev[i].events & EPOLLOUT))
225	stdout_writable = true;
226
227	} else if (ev[i].data.fd == fd) {
228
229	if (ev[i].events & EPOLLHUP) {
230	fd_writable = false;
231	fd_whup = true;
232	}
233
234	if (!fd_rhup && (ev[i].events & (EPOLLHUP\|EPOLLIN)))
235	fd_readable = true;
236
237	if (!fd_whup && (ev[i].events & EPOLLOUT))
238	fd_writable = true;
239	}
240	}
241
242	while ((stdin_readable && in_buffer_full <= 0) \|\|
243	(fd_writable && patch_in_buffer(in_buffer, &in_buffer_full) > 0) \|\|
244	(fd_readable && out_buffer_full <= 0) \|\|
245	(stdout_writable && out_buffer_full > 0)) {
246
247	size_t in_buffer_good = 0;
248
249	if (stdin_readable && in_buffer_full < BUFFER_SIZE) {
250
251	if ((k = read(STDIN_FILENO, in_buffer + in_buffer_full, BUFFER_SIZE - in_buffer_full)) < 0) {
252
253	if (errno == EAGAIN)
254	stdin_readable = false;
255	else if (errno == EPIPE \|\| errno == ECONNRESET)
256	k = 0;
257	else {
258	log_error("read(): %m");
259	goto finish;
260	}
261	} else
262	in_buffer_full += (size_t) k;
263
264	if (k == 0) {
265	stdin_rhup = true;
266	stdin_readable = false;
267	shutdown(STDIN_FILENO, SHUT_RD);
268	close_nointr_nofail(STDIN_FILENO);
269	}
270	}
271
272	in_buffer_good = patch_in_buffer(in_buffer, &in_buffer_full);
273
274	if (fd_writable && in_buffer_good > 0) {
275
276	if ((k = write(fd, in_buffer, in_buffer_good)) < 0) {
277
278	if (errno == EAGAIN)
279	fd_writable = false;
280	else if (errno == EPIPE \|\| errno == ECONNRESET) {
281	fd_whup = true;
282	fd_writable = false;
283	shutdown(fd, SHUT_WR);
284	} else {
285	log_error("write(): %m");
286	goto finish;
287	}
288
289	} else {
290	assert(in_buffer_full >= (size_t) k);
291	memmove(in_buffer, in_buffer + k, in_buffer_full - k);
292	in_buffer_full -= k;
293	}
294	}
295
296	if (fd_readable && out_buffer_full < BUFFER_SIZE) {
297
298	if ((k = read(fd, out_buffer + out_buffer_full, BUFFER_SIZE - out_buffer_full)) < 0) {
299
300	if (errno == EAGAIN)
301	fd_readable = false;
302	else if (errno == EPIPE \|\| errno == ECONNRESET)
303	k = 0;
304	else {
305	log_error("read(): %m");
306	goto finish;
307	}
308	} else
309	out_buffer_full += (size_t) k;
310
311	if (k == 0) {
312	fd_rhup = true;
313	fd_readable = false;
314	shutdown(fd, SHUT_RD);
315	}
316	}
317
318	if (stdout_writable && out_buffer_full > 0) {
319
320	if ((k = write(STDOUT_FILENO, out_buffer, out_buffer_full)) < 0) {
321
322	if (errno == EAGAIN)
323	stdout_writable = false;
324	else if (errno == EPIPE \|\| errno == ECONNRESET) {
325	stdout_whup = true;
326	stdout_writable = false;
327	shutdown(STDOUT_FILENO, SHUT_WR);
328	close_nointr(STDOUT_FILENO);
329	} else {
330	log_error("write(): %m");
331	goto finish;
332	}
333
334	} else {
335	assert(out_buffer_full >= (size_t) k);
336	memmove(out_buffer, out_buffer + k, out_buffer_full - k);
337	out_buffer_full -= k;
338	}
339	}
340	}
341
342	if (stdin_rhup && in_buffer_full <= 0 && !fd_whup) {
343	fd_whup = true;
344	fd_writable = false;
345	shutdown(fd, SHUT_WR);
346	}
347
348	if (fd_rhup && out_buffer_full <= 0 && !stdout_whup) {
349	stdout_whup = true;
350	stdout_writable = false;
351	shutdown(STDOUT_FILENO, SHUT_WR);
352	close_nointr(STDOUT_FILENO);
353	}
354
355	} while (!stdout_whup \|\| !fd_whup);
356
357	r = EXIT_SUCCESS;
358
359	finish:
360	if (fd >= 0)
361	close_nointr_nofail(fd);
362
363	if (ep >= 0)
364	close_nointr_nofail(ep);
365
366	return r;
367	}