summaryrefslogtreecommitdiffstats
path: root/server/util/server.c
blob: e8d26dcf0ed75996a76595cd84f388f06fba71af (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
/*
   SSSD

   Servers setup routines

   Copyright (C) Andrew Tridgell		1992-2005
   Copyright (C) Martin Pool			2002
   Copyright (C) Jelmer Vernooij		2002
   Copyright (C) James J Myers 			2003 <myersjj@samba.org>
   Copyright (C) Simo Sorce			2008

   This program 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 3 of the License, or
   (at your option) any later version.

   This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
*/

#define _GNU_SOURCE
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include "util/util.h"
#include "ldb.h"
#include "confdb/confdb.h"

#ifdef HAVE_PRCTL
#include <sys/prctl.h>
#endif

/*******************************************************************
 Close the low 3 fd's and open dev/null in their place.
********************************************************************/
static void close_low_fds()
{
#ifndef VALGRIND
	int fd;
	int i;

	close(0);
	close(1);
	close(2);

	/* try and use up these file descriptors, so silly
		library routines writing to stdout etc won't cause havoc */
	for (i=0;i<3;i++) {
		fd = open("/dev/null",O_RDWR,0);
		if (fd < 0)
			fd = open("/dev/null",O_WRONLY,0);
		if (fd < 0) {
			DEBUG(0,("Can't open /dev/null\n"));
			return;
		}
		if (fd != i) {
			DEBUG(0,("Didn't get file descriptor %d\n",i));
			return;
		}
	}
#endif
}

/**
 Become a daemon, discarding the controlling terminal.
**/

void become_daemon(bool Fork)
{
        int ret;

	if (Fork) {
		if (fork()) {
			_exit(0);
		}
	}

    /* detach from the terminal */
	setsid();

        /* chdir to / to be sure we're not on a remote filesystem */
        errno = 0;
        if(chdir("/") == -1) {
            ret = errno;
            DEBUG(0, ("Cannot change directory (%d [%s])\n",
                    ret, strerror(ret)));
            return;
        }

	/* Close fd's 0,1,2. Needed if started by rsh */
	close_low_fds();
}

int pidfile(const char *path, const char *name)
{
    char pid_str[32];
    pid_t pid;
    char *file;
    int fd;
    int ret, err;

    file = talloc_asprintf(NULL, "%s/%s.pid", path, name);
    if (!file) {
        return ENOMEM;
    }

    fd = open(file, O_RDONLY, 0644);
    err = errno;
    if (fd != -1) {

        pid_str[sizeof(pid_str) -1] = '\0';
        ret = read(fd, pid_str, sizeof(pid_str) -1);
        if (ret > 0) {
            /* let's check the pid */

            pid = (pid_t)atoi(pid_str);
            if (pid != 0) {
                errno = 0;
                ret = kill(pid, 0);
                /* succeeded in signaling the process -> another sssd process */
                if (ret == 0) {
                    close(fd);
                    talloc_free(file);
                    return EEXIST;
                }
                if (ret != 0 && errno != ESRCH) {
                    err = errno;
                    close(fd);
                    talloc_free(file);
                    return err;
                }
            }
        }

        /* nothing in the file or no process */
        close(fd);
        unlink(file);

    } else {
        if (err != ENOENT) {
            talloc_free(file);
            return err;
        }
    }

    fd = open(file, O_CREAT | O_WRONLY | O_EXCL, 0644);
    err = errno;
    if (fd == -1) {
        talloc_free(file);
        return err;
    }
    talloc_free(file);

    memset(pid_str, 0, sizeof(pid_str));
    snprintf(pid_str, sizeof(pid_str) -1, "%u\n", (unsigned int) getpid());

    ret = write(fd, pid_str, strlen(pid_str));
    err = errno;
    if (ret != strlen(pid_str)) {
        close(fd);
        return err;
    }

    close(fd);

    return 0;
}

static void sig_hup(int sig)
{
	/* cycle log/debug files */
	return;
}

static void sig_term(int sig)
{
#if HAVE_GETPGRP
	static int done_sigterm;
	if (done_sigterm == 0 && getpgrp() == getpid()) {
		DEBUG(0,("SIGTERM: killing children\n"));
		done_sigterm = 1;
		kill(-getpgrp(), SIGTERM);
	}
#endif
	exit(0);
}

#ifndef HAVE_PRCTL
static void sig_segv_abrt(int sig)
{
#if HAVE_GETPGRP
	static int done;
	if (done == 0 && getpgrp() == getpid()) {
		DEBUG(0,("%s: killing children\n", strsignal(sig)));
		done = 1;
		kill(-getpgrp(), SIGTERM);
	}
#endif  /* HAVE_GETPGRP */
    exit(1);
}
#endif /* HAVE_PRCTL */

/*
  setup signal masks
*/
static void setup_signals(void)
{
	/* we are never interested in SIGPIPE */
	BlockSignals(true, SIGPIPE);

#if defined(SIGFPE)
	/* we are never interested in SIGFPE */
	BlockSignals(true, SIGFPE);
#endif

	/* We are no longer interested in USR1 */
	BlockSignals(true, SIGUSR1);

#if defined(SIGUSR2)
	/* We are no longer interested in USR2 */
	BlockSignals(true, SIGUSR2);
#endif

	/* POSIX demands that signals are inherited. If the invoking process has
	 * these signals masked, we will have problems, as we won't recieve them. */
	BlockSignals(false, SIGHUP);
	BlockSignals(false, SIGTERM);

	CatchSignal(SIGHUP, sig_hup);
	CatchSignal(SIGTERM, sig_term);

#ifndef HAVE_PRCTL
        /* If prctl is not defined on the system, try to handle
         * some common termination signals gracefully */
	CatchSignal(SIGSEGV, sig_segv_abrt);
	CatchSignal(SIGABRT, sig_segv_abrt);
#endif

}

/*
  handle io on stdin
*/
static void server_stdin_handler(struct tevent_context *event_ctx,
                                 struct tevent_fd *fde,
                                 uint16_t flags, void *private)
{
	const char *binary_name = (const char *)private;
	uint8_t c;
	if (read(0, &c, 1) == 0) {
		DEBUG(0,("%s: EOF on stdin - terminating\n", binary_name));
#if HAVE_GETPGRP
		if (getpgrp() == getpid()) {
			kill(-getpgrp(), SIGTERM);
		}
#endif
		exit(0);
	}
}

/*
 main server helpers.
*/

int die_if_parent_died(void)
{
#ifdef HAVE_PRCTL
    int ret;

    errno = 0;
    ret = prctl(PR_SET_PDEATHSIG, SIGTERM, 0, 0, 0);
    if (ret != 0) {
        ret = errno;
        DEBUG(2, ("prctl failed [%d]: %s", ret, strerror(ret)));
        return ret;
    }
#endif
    return EOK;
}

int server_setup(const char *name, int flags,
                 const char *conf_entry,
                 struct main_context **main_ctx)
{
    struct tevent_context *event_ctx;
    struct main_context *ctx;
    uint16_t stdin_event_flags;
    char *conf_db;
    int ret = EOK;
    bool dt;
    bool dl;

    debug_prg_name = strdup(name);
    if (!debug_prg_name) {
        return ENOMEM;
    }

    setenv("_SSS_LOOPS", "NO", 0);

    setup_signals();

    /* we want default permissions on created files to be very strict,
       so set our umask to 0177 */
    umask(0177);

    if (flags & FLAGS_DAEMON) {
        DEBUG(3,("Becoming a daemon.\n"));
        become_daemon(true);
    }

    if (flags & FLAGS_PID_FILE) {
        ret = pidfile(PID_PATH, name);
        if (ret != EOK) {
            DEBUG(0, ("Error creating pidfile! (%d [%s])\n",
                      ret, strerror(ret)));
            return ret;
        }
    }

    /* Set up locale */
    setlocale (LC_ALL, "");
    bindtextdomain (PACKAGE, LOCALEDIR);
    textdomain (PACKAGE);

    /* the event context is the top level structure.
     * Everything else should hang off that */
    event_ctx = tevent_context_init(talloc_autofree_context());
    if (event_ctx == NULL) {
        DEBUG(0,("The event context initialiaziton failed\n"));
        return 1;
    }

    ctx = talloc(event_ctx, struct main_context);
    if (ctx == NULL) {
        DEBUG(0,("Out of memory, aborting!\n"));
        return ENOMEM;
    }

    ctx->event_ctx = event_ctx;

    conf_db = talloc_asprintf(ctx, "%s/%s", DB_PATH, CONFDB_FILE);
    if (conf_db == NULL) {
        DEBUG(0,("Out of memory, aborting!\n"));
        return ENOMEM;
    }

    ret = confdb_init(ctx, &ctx->confdb_ctx, conf_db);
    if (ret != EOK) {
        DEBUG(0,("The confdb initialization failed\n"));
        return ret;
    }

    /* set debug level if any in conf_entry */
    ret = confdb_get_int(ctx->confdb_ctx, ctx, conf_entry,
                         CONFDB_SERVICE_DEBUG_LEVEL,
                         debug_level, &debug_level);
    if (ret != EOK) {
        DEBUG(0, ("Error reading from confdb (%d) [%s]\n",
                  ret, strerror(ret)));
        return ret;
    }

    /* same for debug timestamps */
    dt = (debug_timestamps != 0);
    ret = confdb_get_bool(ctx->confdb_ctx, ctx, conf_entry,
                          CONFDB_SERVICE_DEBUG_TIMESTAMPS,
                          dt, &dt);
    if (ret != EOK) {
        DEBUG(0, ("Error reading from confdb (%d) [%s]\n",
                  ret, strerror(ret)));
        return ret;
    }
    if (dt) debug_timestamps = 1;

    /* same for debug to file */
    dl = (debug_to_file != 0);
    ret = confdb_get_bool(ctx->confdb_ctx, ctx, conf_entry,
                          CONFDB_SERVICE_DEBUG_TO_FILES,
                          dl, &dl);
    if (ret != EOK) {
        DEBUG(0, ("Error reading from confdb (%d) [%s]\n",
                  ret, strerror(ret)));
        return ret;
    }
    if (dl) debug_to_file = 1;

    /* open log file if told so */
    if (debug_to_file) {
        ret = open_debug_file();
        if (ret != EOK) {
            DEBUG(0, ("Error setting up logging (%d) [%s]\n",
                    ret, strerror(ret)));
            return ret;
        }
    }

    DEBUG(3, ("CONFDB: %s\n", conf_db));

    if (flags & FLAGS_INTERACTIVE) {
        /* terminate when stdin goes away */
        stdin_event_flags = TEVENT_FD_READ;
    } else {
        /* stay alive forever */
        stdin_event_flags = 0;
    }

    /* catch EOF on stdin */
#ifdef SIGTTIN
    signal(SIGTTIN, SIG_IGN);
#endif
    tevent_add_fd(event_ctx, event_ctx, 0, stdin_event_flags,
                 server_stdin_handler, discard_const(name));

    *main_ctx = ctx;
    return EOK;
}

void server_loop(struct main_context *main_ctx)
{
    /* wait for events - this is where the server sits for most of its
       life */
    tevent_loop_wait(main_ctx->event_ctx);

    /* as everything hangs off this event context, freeing it
       should initiate a clean shutdown of all services */
    talloc_free(main_ctx->event_ctx);
}