1 // vim: ts=4 sw=4 noet:
3 --------------------------------------------------------------------------------
4 Copyright (c) 2018-2019 AT&T Intellectual Property.
6 Licensed under the Apache License, Version 2.0 (the "License");
7 you may not use this file except in compliance with the License.
8 You may obtain a copy of the License at
10 http://www.apache.org/licenses/LICENSE-2.0
12 Unless required by applicable law or agreed to in writing, software
13 distributed under the License is distributed on an "AS IS" BASIS,
14 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15 See the License for the specific language governing permissions and
16 limitations under the License.
17 --------------------------------------------------------------------------------
22 Abstract: The mc listener library content. All external functions
23 should start with mcl_ and all stderr messages should have
24 (mcl) as the first token following the severity indicator.
27 Author: E. Scott Daniels
39 #include <sys/types.h>
43 #include <rmr/rmr_symtab.h>
54 Information about one file descriptor. This is pointed to by the hash
55 such that the message type can be used as a key to look up the fifo's
60 int key; // symtab key
61 long long wcount; // number of writes
62 long long drops; // number dropped
64 long long wcount_rp; // number of writes during last reporting period
65 long long drops_rp; // number dropped during last reporting period
69 Our conext. Pointers to the read and write hash tables (both keyed on the message
70 type), the message router (RMR) context, and other goodies.
73 void* mrc; // the message router's context
74 void* wr_hash; // symtable to look up pipe info based on mt for writing
75 void* rd_hash; // we support reading from pipes, but need a different FD for that
76 char* fifo_dir; // directory where we open fifos
80 // -------- private -------------------------------------------------------
84 Set up for raw data capture. We look for directory overriedes from
85 environment variables, and then invoke the rdc_init() to actually
88 static void* setup_rdc() {
90 int value; // value computed for something
91 char* ep; // pointer to environment var
92 char* sdir = "/tmp/rdc/stage"; // default directory names
93 char* fdir = "/tmp/rdc/final";
94 char* suffix = ".rdc";
97 if( (ep = getenv( "MCL_RDC_ENABLE" )) != NULL ) {
98 if( ep != NULL && atoi( ep ) == 0 ) {
99 logit( LOG_INFO, "(mcl) raw data capture disabled by environment var setting: MCL_RDC_ENABLE=%s", ep );
104 if( (ep = getenv( "MCL_RDC_STAGE" )) != NULL ) {
107 mkdir( "/tmp/rdc", 0755 ); // we ignore failures here as it could likely exist
111 if( (ep = getenv( "MCL_RDC_FINAL" )) != NULL ) {
114 mkdir( "/tmp/rdc", 0755 ); // we ignore failures again -- very likely it's there
118 if( (ep = getenv( "MCL_RDC_SUFFIX" )) != NULL ) {
122 if( (ep = getenv( "MCL_RDC_DONE" )) != NULL ) {
126 ctx = rdc_init( sdir, fdir, suffix, done );
128 logit( LOG_ERR, "rdc_init did not generate a context" );
130 logit( LOG_INFO, "raw data capture files will be staged in: %s", sdir );
131 logit( LOG_INFO, "raw data capture files will be moved for copy to: %s", fdir );
134 if( (ep = getenv( "MCL_RDC_FREQ" )) != NULL ) {
136 logit( LOG_INFO, "setting frequency: %d", value );
137 rdc_set_freq( ctx, value );
143 Builds an extended header in the buffer provided, or allocates a new buffer if
144 dest is nil. The header is of the form:
145 <delim><len><timestamp>
147 Timestamp is a single unsigned long long in ASCII; ms since epoch.
148 If the current time is 2019/10/03 10:39:51.103 which is 1570113591.103
149 the timestamp generated will be 1570113591103.
151 static char* build_hdr( int len, char* dest, int dest_len ) {
152 struct timespec ts; // time just before call executed
156 dest = (char *) malloc( sizeof( char ) * dest_len );
158 if( dest_len < 28 ) { // shouldn't happen, but take no chances
159 memset( dest, 0, dest_len );
164 memset( dest, 0, dest_len );
166 clock_gettime( CLOCK_REALTIME, &ts );
167 sprintf( dest, "%s%07d", MCL_DELIM, len );
168 sprintf( dest+12, "%ld%03ld", ts.tv_sec, ts.tv_nsec/1000000 );
174 Build a file name and open. The io_direction is either READER or
175 WRITER. For a writer we must 'trick' the system into allowing us
176 to open a pipe for writing in non-blocking mode so that we can
177 report on drops (messages we couldn't write because there was no
178 reader). The trick is to open a reader on the pipe so that when
179 we open the writer there's a reader and the open won't fail. As
180 soon as we have the writer open, we can close the junk reader.
182 If the desired fifo does not exist, it is created.
184 static int open_fifo( mcl_ctx_t* ctx, int mtype, int io_dir ) {
186 int fd; // real file des
187 int jfd = -1; // junk file des
190 if( ctx == NULL || mtype < 0 ) {
194 snprintf( wbuf, sizeof( wbuf ), "%s/MT_%09d", ctx->fifo_dir, mtype );
196 state = mkfifo( wbuf, 0660 ); // make the fifo; this will fail if it exists and that's ok
197 if( state != 0 && errno != EEXIST ) {
198 logit( LOG_ERR, "(mcl) unable to create fifo: %s: %s", wbuf, strerror( errno ) );
202 if( io_dir == READER ) {
203 fd = open( wbuf, O_RDONLY ); // just open the reader
205 logit( LOG_ERR, "(mcl) fifo open failed (ro): %s: %s", wbuf, strerror( errno ) );
208 jfd = open( wbuf, O_RDWR | O_NONBLOCK ); // must have a reader before we can open a non-blocking writer
210 logit( LOG_ERR, "(mcl) fifo open failed (rw): %s: %s", wbuf, strerror( errno ) );
213 fd = open( wbuf, O_WRONLY | O_NONBLOCK ); // this will be our actual writer, in non-blocking mode
215 logit( LOG_ERR, "(mcl) fifo open failed (wo): %s: %s", wbuf, strerror( errno ) );
218 close( jfd ); // should be safe to close this
226 Given a message type, return the file des of the fifo that
227 the payload should be written to. Returns the file des, or -1
228 on error. When sussing out a read file descriptor this will
229 block until there is a fifo for the message type which is
232 If fref is not nil, then a pointer to the fifo info block is returned
233 allowing for direct update of counts after the write.
235 static int suss_fifo( mcl_ctx_t* ctx, int mtype, int io_dir, fifo_t** fref ) {
239 if( io_dir == READER ) { // with an integer key, we nned two hash tables
245 if( (fifo = (fifo_t *) rmr_sym_pull( hash, mtype )) == NULL ) {
246 fifo = (fifo_t *) malloc( sizeof( *fifo ) );
251 memset( fifo, 0, sizeof( *fifo ) );
253 fifo->fd = open_fifo( ctx, mtype, io_dir );
254 rmr_sym_map( hash, mtype, fifo );
264 Make marking counts easier in code
266 static inline void chalk_error( fifo_t* fifo ) {
273 static inline void chalk_ok( fifo_t* fifo ) {
281 Callback function driven to traverse the symtab and generate the
282 counts for each fifo.
284 static void wr_stats( void* st, void* entry, char const* name, void* thing, void* data ) {
286 int report_period = 60;
289 report_period = *((int *) data);
292 if( (fifo = (fifo_t *) thing) != NULL ) {
293 logit( LOG_STAT, "(mcl) mtype=%d total writes=%lld total drops=%lld; during last %ds writes=%lld drops=%lld",
294 fifo->key, fifo->wcount, fifo->drops, report_period, fifo->wcount_rp, fifo->drops_rp );
296 fifo->wcount_rp = 0; // reset the report counts
301 // ---------- public ------------------------------------------------------
303 Sets a signal handler for sigpipe so we don't crash if a reader closes the
304 last reading fd on a pipe. We could do this automatically, but if the user
305 programme needs to trap sigpipe too, this gives them the option not to have
308 extern int mcl_set_sigh( ) {
309 signal( SIGPIPE, SIG_IGN );
313 "Opens" the interface to RMR such that messages sent to the application will
314 be available via the rmr receive funcitons. This is NOT automatically called
315 by the mk_context function as some applications will be using the mc library
316 for non-RMR, fifo, chores.
318 extern int mcl_start_listening( void* vctx, char* port, int wait4ready ) {
322 if( (ctx = (mcl_ctx_t*) vctx) == NULL ) {
326 ctx->mrc = rmr_init( port, RMR_MAX_RCV_BYTES, RMRFL_NONE ); // start your engines!
327 if( ctx->mrc == NULL ) {
328 logit( LOG_CRIT, "start listening: unable to initialise RMr" );
332 while( wait4ready && ! rmr_ready( ctx->mrc ) ) { // only senders need to wait
333 if( announce <= 0 ) {
334 logit( LOG_INFO, "waiting for RMR to show ready" );
347 Blocks until a message arives with a good return code or we timeout. Returns the
348 rmr message buffer. Timeout value epxected in seconds.
350 extern rmr_mbuf_t* mcl_get_msg( void* vctx, rmr_mbuf_t* msg, int timeout ) {
353 if( (ctx = (mcl_ctx_t *) vctx) == NULL ) {
357 if( ctx->mrc == NULL ) {
358 logit( LOG_CRIT, "get msg: abort: bad rmr context reference (nil)" );
363 msg = rmr_torcv_msg( ctx->mrc, msg, timeout * 1000 ); // wait for next
364 } while( msg == NULL || (msg->state != RMR_OK && msg->state != RMR_ERR_TIMEOUT) );
372 extern void* mcl_mk_context( char* dir ) {
375 if( (ctx = (mcl_ctx_t *) malloc( sizeof( *ctx ) )) != NULL ) {
376 memset( ctx, 0, sizeof( *ctx ) );
377 ctx->fifo_dir = strdup( dir );
378 ctx->wr_hash = rmr_sym_alloc( 1001 );
379 ctx->rd_hash = rmr_sym_alloc( 1001 );
381 if( ctx->wr_hash == NULL || ctx->rd_hash == NULL ) {
382 logit( LOG_ERR, "(mcl) unable to allocate hash table for fifo keys" );
392 Read the header. Best case we read the expected number of bytes, get all
393 of them and find that they start with the delemiter. Worst case
394 We have to wait for all of the header, or need to synch at the next
395 delimeter. We assume best case most likely and handle it as such.
397 static void read_header( int fd, char* buf ) {
399 int need = MCL_EXHDR_SIZE; // total needed
400 int dneed; // delimieter needed
402 char* rp; // read position in buf
404 len = read( fd, buf, need );
405 if( len == need && strncmp( buf, MCL_DELIM, strlen( MCL_DELIM )) == 0 ) { // best case, most likely
410 if( len < strlen( MCL_DELIM ) ) { // must get at least enough bytes to check delim
412 dneed = strlen( MCL_DELIM ) - len;
415 len = read( fd, rp, dneed );
421 if( strncmp( buf, MCL_DELIM, strlen( MCL_DELIM )) == 0 ) { // have a good delimiter, just need to wait for bytes
422 need = MCL_EXHDR_SIZE - strlen( MCL_DELIM );
423 rp = buf + (MCL_EXHDR_SIZE - need);
426 len = read( fd, rp, need );
434 while( buf[0] != MCL_DELIM[0] ) { // wait for a recognised start byte to be read (may cause an additional message drop
435 len = read( fd, buf, 1 ); // because we ignore start byte that might be in the buffer)
438 need = MCL_EXHDR_SIZE - len;
444 Read one record from the fifo that the message type maps to.
445 Writes at max ublen bytes into the ubuf.
447 If long_hdrs is true (!0), then we expect that the stream in the fifo
448 has extended headers (<delim><len><time>), and will write the timestamp
449 from the header into the buffer pointed to by timestamp. The buffer is
450 assumed to be at least MCL_TSTAMP_SIZE bytes in length.
452 Further, when extended headers are being used, this function will
453 automatically resynchronise if it detects an issue.
455 The function could look for the delimiter and automatically detect whether
456 or not extended headers are in use, but if the stream is out of synch on the
457 first read, this cannot be done, so the funciton requires that the caller
458 know that the FIFO contains extended headers.
460 static int fifo_read1( void *vctx, int mtype, char* ubuf, int ublen, int long_hdrs, char* timestamp ) {
464 int got = 0; // number of bytes we actually got
467 mcl_ctx_t* ctx; // our context; mostly for the rmr context reference and symtable
468 fifo_t* fref = NULL; // the fifo struct we found
470 if( (ctx = (mcl_ctx_t*) vctx) == NULL ) {
475 if( (fd = suss_fifo( ctx, mtype, READER, NULL )) >= 0 ) {
477 read_header( fd, wbuf );
478 msg_len = need = atoi( wbuf + MCL_LEN_OFF ); // read the length
480 strcpy( timestamp, wbuf + MCL_TSTAMP_OFF+1 );
483 if( timestamp != NULL ) { // won't be there, but ensure it's not garbage
487 len = read( fd, wbuf, MCL_LEN_SIZE ); // we assume we will get all 8 as there isn't a way to sync the old stream
488 msg_len = need = atoi( wbuf );
493 need = ublen; // cannot give them more than they can take
496 len = read( fd, wbuf, need > sizeof( wbuf ) ? sizeof( wbuf ) : need );
497 memcpy( ubuf+got, wbuf, len );
502 if( msg_len > got ) { // we must ditch rest of this message
503 need = msg_len = got;
505 len = read( fd, wbuf, need > sizeof( wbuf ) ? sizeof( wbuf ) : need );
518 Read one record from the fifo that the message type maps to.
519 Writes at max ublen bytes into the ubuf. If extended headers are in use
520 this function will ignore the timestamp.
522 If long_hdrs is true (!0), then we expect that the stream in the fifo
523 has extended headers (<delim><len><time>).
525 extern int mcl_fifo_read1( void *vctx, int mtype, char* ubuf, int ublen, int long_hdrs ) {
526 return fifo_read1( vctx, mtype, ubuf, ublen, long_hdrs, NULL );
530 Read a single message from the FIFO returning it in the caller's buffer. If extended
531 headers are being used, and the caller supplied a timestamp buffer, the timestamp
532 which was in the header will be returned in that buffer. The return value is the number
533 of bytes in the buffer; 0 indicates an error and errno should be set.
535 extern int mcl_fifo_tsread1( void *vctx, int mtype, char* ubuf, int ublen, int long_hdrs, char *timestamp ) {
536 return fifo_read1( vctx, mtype, ubuf, ublen, long_hdrs, timestamp );
541 Will read messages and fan them out based on the message type. This should not
542 return and if it does the caller should assume an error.
544 The output to each fifo is MCL_LEN_SIZE bytes with an ASCII, zero terminated, length
545 string , followed by that number of 'raw' bytes. The raw bytes are the payload
548 The report parameter is the frequency, in seconds, for writing a short
549 status report to stdout. If 0 then it's off.
551 If long_hdr is true, then we geneate an extended header with a delimiter and
554 extern void mcl_fifo_fanout( void* vctx, int report, int long_hdr ) {
555 mcl_ctx_t* ctx; // our context; mostly for the rmr context reference and symtable
556 fifo_t* fifo; // fifo to chalk counts on
557 rmr_mbuf_t* mbuf = NULL; // received message buffer; recycled on each call
558 char header[128]; // header we'll pop in front of the payload
560 int fd; // file des to write to
561 long long total = 0; // total messages received and written
562 long long total_drops = 0; // total messages received and written
563 long count = 0; // messages received and written during last reporting period
564 long errors = 0; // unsuccessful payload writes
565 long drops; // number of drops
566 time_t next_report = 0; // we'll report every 2 seconds if report is true
568 int hwlen; // write len for header
569 void* rdc_ctx = NULL; // raw data capture context
570 void* rdc_buf = NULL; // capture buffer
572 if( (ctx = (mcl_ctx_t*) vctx) == NULL ) {
573 logit( LOG_ERR, "(mcl) invalid context given to fanout" );
582 rdc_ctx = setup_rdc( ); // pull rdc directories from enviornment and initialise
585 mbuf = mcl_get_msg( ctx, mbuf, report ); // wait up to report sec for msg (0 == block until message)
587 if( mbuf != NULL && mbuf->state == RMR_OK && mbuf->len > 0 ) {
588 fd = suss_fifo( ctx, mbuf->mtype, WRITER, &fifo ); // map the message type to an open fd
591 build_hdr( mbuf->len, header, sizeof( header ) );
592 hwlen = MCL_EXHDR_SIZE;
594 snprintf( header, sizeof( header ), "%07d", mbuf->len ); // size of payload CAUTION: 7d is MCL_LEN_SIZE-1
595 hwlen = MCL_LEN_SIZE;
598 if( (state = write( fd, header, hwlen )) != hwlen ) { // write exactly MCL_LEN_SIZE bytes from the buffer
603 if( write( fd, mbuf->payload, mbuf->len ) < mbuf->len ) { // followed by the payload
614 if( rdc_ctx != NULL ) {
615 rdc_buf = rdc_init_buf( mbuf->mtype, header, hwlen, rdc_buf ); // set up for write
616 rdc_write( rdc_ctx, rdc_buf, mbuf->payload, mbuf->len ); // write the raw data
621 if( (now = time( NULL ) ) > next_report ) {
622 rmr_sym_foreach_class( ctx->wr_hash, 0, wr_stats, &report ); // run endpoints in the active table
625 logit( LOG_STAT, "(mcl) total writes=%lld total drops=%lld; during last %ds writes=%ld drops=%ld errs=%ld errors",
626 total, total_drops, report, count, drops, errors );
627 next_report = now + report;