1 /*
2 ** OSSP l2 - Flexible Logging
3 ** Copyright (c) 2001-2005 Cable & Wireless <http://www.cw.com/>
4 ** Copyright (c) 2001-2005 The OSSP Project <http://www.ossp.org/>
5 ** Copyright (c) 2001-2005 Ralf S. Engelschall <rse@engelschall.com>
6 **
7 ** This file is part of OSSP l2, a flexible logging library which
8 ** can be found at http://www.ossp.org/pkg/lib/l2/.
9 **
10 ** Permission to use, copy, modify, and distribute this software for
11 ** any purpose with or without fee is hereby granted, provided that
12 ** the above copyright notice and this permission notice appear in all
13 ** copies.
14 **
15 ** THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
16 ** WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
17 ** MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18 ** IN NO EVENT SHALL THE AUTHORS AND COPYRIGHT HOLDERS AND THEIR
19 ** CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
20 ** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
21 ** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
22 ** USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
23 ** ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
24 ** OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
25 ** OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 ** SUCH DAMAGE.
27 **
28 ** l2_ch_buffer.c: buffering channel implementation
29 */
30
31 #include "l2.h"
32 #include "l2_p.h" /* for TRACE macro */
33
34 #include <string.h>
35 #include <unistd.h> /* for alarm(3) */
36 #include <signal.h> /* for sigaction(2) and SIGALRM */
37
38 #ifdef HAVE_SYS_TIME_H
39 #include <sys/time.h> /* for setitimer(2) */
40 #endif
41
42 #define L2_BUFFER_TIMER ITIMER_REAL /* calls to [s|g]etitimer() and alarm() */
43
44 /* declare private channel configuration */
45 typedef struct {
46 char *buf;
47 int bufpos;
48 int bufsize;
49 long bufinterval;
50 struct sigaction sigalrm;
51 #if defined(HAVE_SETITIMER) && defined(HAVE_SYS_TIME_H)
52 struct itimerval valprev;
53 #endif
54 int levelflush;
55 l2_level_t level;
56 } l2_ch_buffer_t;
57
58 /* Sets the VIRTUAL timer to preconfigured value in cfg */
set_alarm(l2_ch_buffer_t * cfg)59 static int set_alarm(l2_ch_buffer_t *cfg)
60 {
61 #if defined(HAVE_SETITIMER) && defined(HAVE_SYS_TIME_H)
62 struct itimerval valtest, valnew;
63
64 /* initialize auto vars before using them */
65 memset(&valnew, 0, sizeof(valnew));
66
67 valnew.it_interval.tv_sec = cfg->bufinterval;
68 valnew.it_interval.tv_usec = 0;
69 valnew.it_value.tv_sec = cfg->bufinterval;
70 valnew.it_value.tv_usec = 0;
71 if ((getitimer(L2_BUFFER_TIMER, &valtest) == 0) &&
72 ((valtest.it_value.tv_sec | valtest.it_value.tv_usec |
73 valtest.it_interval.tv_sec | valtest.it_interval.tv_usec) == 0))
74 return setitimer(L2_BUFFER_TIMER, &valnew, &cfg->valprev);
75 else {
76 cfg->bufinterval = -1L; /* mark this timer as broken */
77 assert(FALSE);
78 return 1; /* to make the compiler happy */
79 }
80 #else
81 unsigned int uiAlarmed = 0;
82
83 assert(uiAlarmed = alarm(cfg->bufinterval));
84 if (uiAlarmed) { /* check if SIGALRM is occupied */
85 alarm(uiAlarmed); /* ...if so, then hack in the old value */
86 cfg->bufinterval = -1L; /* ...mark this timer as broken */
87 }
88 return 0;
89 #endif
90 }
91
92 /* Resets the VIRTUAL timer to preconfigured value in cfg */
reset_alarm(l2_ch_buffer_t * cfg)93 static int reset_alarm(l2_ch_buffer_t *cfg)
94 {
95 #if defined(HAVE_SETITIMER) && defined(HAVE_SYS_TIME_H)
96 struct itimerval valnew;
97
98 /* initialize auto vars before using them */
99 memset(&valnew, 0, sizeof(valnew));
100
101 valnew.it_interval.tv_sec = cfg->bufinterval;
102 valnew.it_interval.tv_usec = 0;
103 valnew.it_value.tv_sec = cfg->bufinterval;
104 valnew.it_value.tv_usec = 0;
105 return setitimer(L2_BUFFER_TIMER, &valnew, 0);
106 #else
107 alarm(cfg->bufinterval);
108 return 0;
109 #endif
110 }
111
catchsignal(int sig,...)112 static void catchsignal(int sig, ...)
113 {
114 va_list ap;
115 static l2_channel_t *ch = NULL;
116 static l2_ch_buffer_t *cfg = NULL;
117
118 if (sig == 0) {
119 va_start(ap, sig);
120 ch = va_arg(ap, l2_channel_t *); /* init the handler just like */
121 cfg = va_arg(ap, l2_ch_buffer_t *); /* Thomas Lotterer does */
122 va_end(ap);
123 }
124 else if (sig == SIGALRM) {
125 TRACE("SIGALRM caught");
126 l2_channel_flush(ch);
127 reset_alarm(cfg); /* alarm(3) doesn't auto-reset like setitime(2) */
128 }
129 }
130
131 /* create channel */
hook_create(l2_context_t * ctx,l2_channel_t * ch)132 static l2_result_t hook_create(l2_context_t *ctx, l2_channel_t *ch)
133 {
134 l2_ch_buffer_t *cfg;
135
136 /* allocate private channel configuration */
137 if ((cfg = (l2_ch_buffer_t *)malloc(sizeof(l2_ch_buffer_t))) == NULL)
138 return L2_ERR_MEM;
139
140 /* initialize configuration with reasonable defaults */
141 cfg->buf = NULL;
142 cfg->bufpos = 0;
143 cfg->bufsize = 4096;
144 cfg->bufinterval = 0;
145 cfg->levelflush = 0;
146 cfg->level = L2_LEVEL_NONE;
147 memset(&cfg->sigalrm, 0, sizeof(cfg->sigalrm));
148 #if defined(HAVE_SETITIMER) && defined(HAVE_SYS_TIME_H)
149 memset(&cfg->valprev, 0, sizeof(cfg->valprev));
150 #endif
151
152 /* link private channel configuration into channel context */
153 ctx->vp = cfg;
154
155 return L2_OK;
156 }
157
158 /* configure channel */
hook_configure(l2_context_t * ctx,l2_channel_t * ch,const char * fmt,va_list * ap)159 static l2_result_t hook_configure(l2_context_t *ctx, l2_channel_t *ch, const char *fmt, va_list *ap)
160 {
161 l2_ch_buffer_t *cfg = (l2_ch_buffer_t *)ctx->vp;
162 l2_param_t pa[4];
163 l2_result_t rv;
164 l2_env_t *env;
165
166 /* feed and call generic parameter parsing engine */
167 L2_PARAM_SET(pa[0], size, INT, &cfg->bufsize);
168 L2_PARAM_SET(pa[1], interval, INT, &cfg->bufinterval);
169 L2_PARAM_SET(pa[2], levelflush, INT, &cfg->levelflush);
170 L2_PARAM_END(pa[3]);
171 l2_channel_env(ch, &env);
172 rv = l2_util_setparams(env, pa, fmt, ap);
173 if (cfg->bufinterval == -1L) /* -1 is reserved by L2 */
174 return L2_ERR_ARG; /* set_alarm() uses it */
175
176 if (cfg->bufsize < 0)
177 return L2_ERR_ARG;
178
179 return rv;
180 }
181
182 /* open channel */
hook_open(l2_context_t * ctx,l2_channel_t * ch)183 static l2_result_t hook_open(l2_context_t *ctx, l2_channel_t *ch)
184 {
185 l2_ch_buffer_t *cfg = (l2_ch_buffer_t *)ctx->vp;
186 struct sigaction locact;
187
188 if ((cfg->bufinterval != 0) && (cfg->bufinterval != -1L)) {
189 /* initialize auto vars before using them */
190 memset(&locact, 0, sizeof(locact));
191
192 locact.sa_handler = (void(*)(int))catchsignal;
193 sigemptyset(&locact.sa_mask);
194 locact.sa_flags = 0;
195
196 catchsignal(0, ch, (l2_ch_buffer_t *)ctx->vp);
197 /* save old signal context before replacing with our own */
198 if (sigaction(SIGALRM, &locact, &cfg->sigalrm) < 0)
199 return L2_ERR_SYS;
200
201 if (set_alarm(cfg)) /* this is our own L2 set_alarm */
202 return L2_ERR_SYS;
203 }
204
205 /* open channel buffer */
206 if (cfg->bufsize > 0) {
207 if ((cfg->buf = malloc(cfg->bufsize)) == NULL)
208 return L2_ERR_MEM;
209 cfg->bufpos = 0;
210 }
211
212 return L2_OK_PASS;
213 }
214
215 /* write to channel */
hook_write(l2_context_t * ctx,l2_channel_t * ch,l2_level_t level,const char * buf,size_t buf_size)216 static l2_result_t hook_write(l2_context_t *ctx, l2_channel_t *ch,
217 l2_level_t level, const char *buf, size_t buf_size)
218 {
219 l2_ch_buffer_t *cfg = (l2_ch_buffer_t *)ctx->vp;
220 l2_channel_t *downstream;
221 l2_result_t rv;
222
223 if (buf_size > (cfg->bufsize - cfg->bufpos)) {
224 /* flush buffer if necessary */
225 if (cfg->bufpos > 0) {
226 downstream = NULL;
227 while ((rv = l2_channel_downstream(ch, &downstream)) == L2_OK)
228 if ((rv = l2_channel_write(downstream, cfg->level, cfg->buf, cfg->bufpos)) != L2_OK)
229 return rv;
230 cfg->bufpos = 0;
231 cfg->level = L2_LEVEL_NONE;
232 }
233 /* pass through immediately to downstream if still too large */
234 if (buf_size > cfg->bufsize) {
235 downstream = NULL;
236 while ((rv = l2_channel_downstream(ch, &downstream)) == L2_OK)
237 if ((rv = l2_channel_write(downstream, level, buf, buf_size)) != L2_OK)
238 return rv;
239 return L2_OK;
240 }
241 }
242
243 /* flush if incoming message level differs from those already in buffer */
244 if ( (cfg->levelflush) /* if different levels force a flush */
245 && (cfg->bufpos > 0) /* and there is something in the buffer */
246 && (cfg->level != L2_LEVEL_NONE) /* and a remembered level is known */
247 && (level != cfg->level) /* and the levels really differ */)
248 {
249 downstream = NULL;
250 while (l2_channel_downstream(ch, &downstream) == L2_OK)
251 if ((rv = l2_channel_write(downstream, cfg->level, cfg->buf, cfg->bufpos)) != L2_OK)
252 return rv;
253 cfg->bufpos = 0;
254 cfg->level = L2_LEVEL_NONE;
255 }
256
257 /* finally write incoming message to channel buffer */
258 memcpy(cfg->buf+cfg->bufpos, buf, buf_size);
259 cfg->bufpos += buf_size;
260 cfg->level = level;
261
262 return L2_OK;
263 }
264
265 /* flush channel */
hook_flush(l2_context_t * ctx,l2_channel_t * ch)266 static l2_result_t hook_flush(l2_context_t *ctx, l2_channel_t *ch)
267 {
268 l2_ch_buffer_t *cfg = (l2_ch_buffer_t *)ctx->vp;
269 l2_channel_t *downstream;
270 l2_result_t rv;
271
272 /* write the buffer contents downstream */
273 TRACE("l2_ch_buffer hook_flush called\n");
274 if (cfg->bufpos > 0) {
275 downstream = NULL;
276 while (l2_channel_downstream(ch, &downstream) == L2_OK)
277 if ((rv = l2_channel_write(downstream, cfg->level, cfg->buf, cfg->bufpos)) != L2_OK)
278 return rv;
279 cfg->bufpos = 0;
280 cfg->level = L2_LEVEL_NONE; /* reset this->context->level */
281 }
282
283 /* reset the flush alarm timer to synchronize the buffer */
284 if ((cfg->bufinterval != 0) && (cfg->bufinterval != -1L))
285 if (reset_alarm(cfg))
286 return L2_ERR_SYS;
287
288 return L2_OK_PASS;
289 }
290
291 /* close channel */
hook_close(l2_context_t * ctx,l2_channel_t * ch)292 static l2_result_t hook_close(l2_context_t *ctx, l2_channel_t *ch)
293 {
294 l2_ch_buffer_t *cfg = (l2_ch_buffer_t *)ctx->vp;
295 l2_channel_t *downstream;
296 l2_result_t rv;
297
298 if ((cfg->bufinterval != 0) && (cfg->bufinterval != -1L)) {
299 #if defined(HAVE_SETITIMER) && defined(HAVE_SYS_TIME_H)
300 if (setitimer(L2_BUFFER_TIMER, &cfg->valprev, 0)) /* restore timer */
301 return L2_ERR_SYS;
302 #else
303 alarm(0);
304 #endif
305 /* restore previous signal context if previously saved & replaced */
306 if (&cfg->sigalrm.sa_handler)
307 if (sigaction(SIGALRM, &cfg->sigalrm, 0) < 0)
308 rv = L2_ERR_SYS;
309 }
310
311 /* write pending data before closing down */
312 if (cfg->bufpos > 0) {
313 downstream = NULL;
314 while (l2_channel_downstream(ch, &downstream) == L2_OK)
315 if ((rv = l2_channel_write(downstream, cfg->level, cfg->buf, cfg->bufpos)) != L2_OK)
316 return rv;
317 cfg->bufpos = 0;
318 cfg->level = L2_LEVEL_NONE; /* reset this->context->level */
319 }
320
321 /* close channel buffer */
322 if (cfg->buf != NULL) {
323 free(cfg->buf);
324 cfg->buf = NULL;
325 }
326
327 return L2_OK_PASS;
328 }
329
330 /* destroy channel */
hook_destroy(l2_context_t * ctx,l2_channel_t * ch)331 static l2_result_t hook_destroy(l2_context_t *ctx, l2_channel_t *ch)
332 {
333 l2_ch_buffer_t *cfg = (l2_ch_buffer_t *)ctx->vp;
334
335 /* destroy channel configuration */
336 if (cfg->buf != NULL)
337 free(cfg->buf);
338 free(cfg);
339
340 return L2_OK_PASS;
341 }
342
343 /* exported channel handler structure */
344 l2_handler_t l2_handler_buffer = {
345 "buffer",
346 L2_CHANNEL_FILTER,
347 hook_create,
348 hook_configure,
349 hook_open,
350 hook_write,
351 hook_flush,
352 hook_close,
353 hook_destroy
354 };
355
356