X-Git-Url: https://git.lttng.org/?a=blobdiff_plain;f=ustd%2Fustd.c;h=b3af3c47efd3700fcb026247577ce8741782e3eb;hb=c8b4275ed4a63a4bc374a9f3dc864725882c750e;hp=d5884dfe040c8bed7667a03e06784e444023c0e1;hpb=3bb568630e172fd8d2a05f85b6f44218c18ce139;p=ust.git

diff --git a/ustd/ustd.c b/ustd/ustd.c
index d5884df..b3af3c4 100644
--- a/ustd/ustd.c
+++ b/ustd/ustd.c
@@ -1,18 +1,18 @@
-/*
- * Copyright (C) 2009  Pierre-Marc Fournier
+/* Copyright (C) 2009  Pierre-Marc Fournier
  *
- * 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 library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
  *
- * This program is distributed in the hope that it will be useful,
+ * This library 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.
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser 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/>.
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA
  */
 
 #define _GNU_SOURCE
@@ -22,39 +22,64 @@
 #include <fcntl.h>
 #include <unistd.h>
 #include <pthread.h>
+#include <signal.h>
 
 #include <stdlib.h>
 #include <stdio.h>
 #include <string.h>
+#include <errno.h>
+#include <assert.h>
 
+#include "ustd.h"
 #include "localerr.h"
 #include "ustcomm.h"
 
-struct list_head buffers = LIST_HEAD_INIT(buffers);
-
-struct buffer_info {
-	char *name;
-	pid_t pid;
-	struct ustcomm_connection conn;
-
-	int shmid;
-	void *mem;
-	int memlen;
+/* return value: 0 = subbuffer is finished, it won't produce data anymore
+ *               1 = got subbuffer successfully
+ *               <0 = error
+ */
 
-	int n_subbufs;
-	int subbuf_size;
+#define GET_SUBBUF_OK 1
+#define GET_SUBBUF_DONE 0
+#define GET_SUBBUF_DIED 2
 
-	int file_fd; /* output file */
+#define PUT_SUBBUF_OK 1
+#define PUT_SUBBUF_DIED 0
+#define PUT_SUBBUF_PUSHED 2
 
-	struct list_head list;
+int test_sigpipe(void)
+{
+	sigset_t sigset;
+	int result;
 
-	long consumed_old;
-};
+	result = sigemptyset(&sigset);
+	if(result == -1) {
+		perror("sigemptyset");
+		return -1;
+	}
+	result = sigaddset(&sigset, SIGPIPE);
+	if(result == -1) {
+		perror("sigaddset");
+		return -1;
+	}
 
-/* return value: 0 = subbuffer is finished, it won't produce data anymore
- *               1 = got subbuffer successfully
- *               <0 = error
- */
+	result = sigtimedwait(&sigset, NULL, &(struct timespec){0,0});
+	if(result == -1 && errno == EAGAIN) {
+		/* no signal received */
+		return 0;
+	}
+	else if(result == -1) {
+		perror("sigtimedwait");
+		return -1;
+	}
+	else if(result == SIGPIPE) {
+		/* received sigpipe */
+		return 1;
+	}
+	else {
+		assert(0);
+	}
+}
 
 int get_subbuffer(struct buffer_info *buf)
 {
@@ -66,11 +91,19 @@ int get_subbuffer(struct buffer_info *buf)
 
 	asprintf(&send_msg, "get_subbuffer %s", buf->name);
 	result = ustcomm_send_request(&buf->conn, send_msg, &received_msg);
-	if(result < 0) {
+	free(send_msg);
+	if(test_sigpipe()) {
+		WARN("process %d destroyed before we could connect to it", buf->pid);
+		return GET_SUBBUF_DONE;
+	}
+	else if(result < 0) {
 		ERR("get_subbuffer: ustcomm_send_request failed");
 		return -1;
 	}
-	free(send_msg);
+	else if(result == 0) {
+		DBG("app died while being traced");
+		return GET_SUBBUF_DIED;
+	}
 
 	result = sscanf(received_msg, "%as %ld", &rep_code, &buf->consumed_old);
 	if(result != 2 && result != 1) {
@@ -82,10 +115,10 @@ int get_subbuffer(struct buffer_info *buf)
 
 	if(!strcmp(rep_code, "OK")) {
 		DBG("got subbuffer %s", buf->name);
-		retval = 1;
+		retval = GET_SUBBUF_OK;
 	}
 	else if(nth_token_is(received_msg, "END", 0) == 1) {
-		return 0;
+		return GET_SUBBUF_DONE;
 	}
 	else {
 		DBG("error getting subbuffer %s", buf->name);
@@ -123,16 +156,20 @@ int put_subbuffer(struct buffer_info *buf)
 
 	if(!strcmp(rep_code, "OK")) {
 		DBG("subbuffer put %s", buf->name);
-		retval = 1;
+		retval = PUT_SUBBUF_OK;
 	}
 	else {
-		ERR("invalid response to put_subbuffer");
+		DBG("put_subbuffer: received error, we were pushed");
+		return PUT_SUBBUF_PUSHED;
 	}
 
 	free(rep_code);
 	return retval;
 }
 
+/* This write is patient because it restarts if it was incomplete.
+ */
+
 ssize_t patient_write(int fd, const void *buf, size_t count)
 {
 	const char *bufc = (const char *) buf;
@@ -160,15 +197,20 @@ void *consumer_thread(void *arg)
 	int result;
 
 	for(;;) {
+		/* get the subbuffer */
 		result = get_subbuffer(buf);
 		if(result == -1) {
 			ERR("error getting subbuffer");
 			continue;
 		}
-		if(result == 0) {
+		else if(result == GET_SUBBUF_DONE) {
 			/* this is done */
 			break;
 		}
+		else if(result == GET_SUBBUF_DIED) {
+			finish_consuming_dead_subbuffer(buf);
+			break;
+		}
 
 		/* write data to file */
 		result = patient_write(buf->file_fd, buf->mem + (buf->consumed_old & (buf->n_subbufs * buf->subbuf_size-1)), buf->subbuf_size);
@@ -177,15 +219,29 @@ void *consumer_thread(void *arg)
 			/* FIXME: maybe drop this trace */
 		}
 
+		/* put the subbuffer */
 		result = put_subbuffer(buf);
 		if(result == -1) {
-			ERR("error putting subbuffer");
+			ERR("unknown error putting subbuffer (channel=%s)", buf->name);
+			break;
+		}
+		else if(result == PUT_SUBBUF_PUSHED) {
+			ERR("Buffer overflow (channel=%s), reader pushed. This channel will not be usable passed this point.", buf->name);
 			break;
 		}
+		else if(result == PUT_SUBBUF_DIED) {
+			WARN("application died while putting subbuffer");
+			/* FIXME: probably need to skip the first subbuffer in finish_consuming_dead_subbuffer */
+			finish_consuming_dead_subbuffer(buf);
+		}
+		else if(result == PUT_SUBBUF_OK) {
+		}
 	}
 
 	DBG("thread for buffer %s is stopping", buf->name);
 
+	/* FIXME: destroy, unalloc... */
+
 	return NULL;
 }
 
@@ -198,6 +254,7 @@ int add_buffer(pid_t pid, char *bufname)
 	char *tmp;
 	int fd;
 	pthread_t thr;
+	struct shmid_ds shmds;
 
 	buf = (struct buffer_info *) malloc(sizeof(struct buffer_info));
 	if(buf == NULL) {
@@ -211,28 +268,35 @@ int add_buffer(pid_t pid, char *bufname)
 	/* connect to app */
 	result = ustcomm_connect_app(buf->pid, &buf->conn);
 	if(result) {
-		ERR("unable to connect to process");
+		WARN("unable to connect to process, it probably died before we were able to connect");
 		return -1;
 	}
 
 	/* get shmid */
 	asprintf(&send_msg, "get_shmid %s", buf->name);
-	ustcomm_send_request(&buf->conn, send_msg, &received_msg);
+	result = ustcomm_send_request(&buf->conn, send_msg, &received_msg);
 	free(send_msg);
-	DBG("got buffer name %s", buf->name);
+	if(result == -1) {
+		ERR("problem in ustcomm_send_request(get_shmid)");
+		return -1;
+	}
 
-	result = sscanf(received_msg, "%d", &buf->shmid);
-	if(result != 1) {
+	result = sscanf(received_msg, "%d %d", &buf->shmid, &buf->bufstruct_shmid);
+	if(result != 2) {
 		ERR("unable to parse response to get_shmid");
 		return -1;
 	}
 	free(received_msg);
-	DBG("got shmid %d", buf->shmid);
+	DBG("got shmids %d %d", buf->shmid, buf->bufstruct_shmid);
 
 	/* get n_subbufs */
 	asprintf(&send_msg, "get_n_subbufs %s", buf->name);
-	ustcomm_send_request(&buf->conn, send_msg, &received_msg);
+	result = ustcomm_send_request(&buf->conn, send_msg, &received_msg);
 	free(send_msg);
+	if(result == -1) {
+		ERR("problem in ustcomm_send_request(g_n_subbufs)");
+		return -1;
+	}
 
 	result = sscanf(received_msg, "%d", &buf->n_subbufs);
 	if(result != 1) {
@@ -261,20 +325,34 @@ int add_buffer(pid_t pid, char *bufname)
 		perror("shmat");
 		return -1;
 	}
-	DBG("successfully attached memory");
+	DBG("successfully attached buffer memory");
+
+	buf->bufstruct_mem = shmat(buf->bufstruct_shmid, NULL, 0);
+	if(buf->bufstruct_mem == (void *) 0) {
+		perror("shmat");
+		return -1;
+	}
+	DBG("successfully attached buffer bufstruct memory");
+
+	/* obtain info on the memory segment */
+	result = shmctl(buf->shmid, IPC_STAT, &shmds);
+	if(result == -1) {
+		perror("shmctl");
+		return -1;
+	}
+	buf->memlen = shmds.shm_segsz;
 
 	/* open file for output */
 	asprintf(&tmp, "/tmp/trace/%s_0", buf->name);
 	result = fd = open(tmp, O_WRONLY | O_CREAT | O_TRUNC, 00600);
 	if(result == -1) {
 		PERROR("open");
+		ERR("failed opening trace file %s", tmp);
 		return -1;
 	}
 	buf->file_fd = fd;
 	free(tmp);
 
-	//list_add(&buf->list, &buffers);
-
 	pthread_create(&thr, NULL, consumer_thread, buf);
 
 	return 0;
@@ -284,6 +362,7 @@ int main(int argc, char **argv)
 {
 	struct ustcomm_ustd ustd;
 	int result;
+	sigset_t sigset;
 
 	result = ustcomm_init_ustd(&ustd);
 	if(result == -1) {
@@ -291,6 +370,22 @@ int main(int argc, char **argv)
 		return 1;
 	}
 
+	result = sigemptyset(&sigset);
+	if(result == -1) {
+		perror("sigemptyset");
+		return 1;
+	}
+	result = sigaddset(&sigset, SIGPIPE);
+	if(result == -1) {
+		perror("sigaddset");
+		return 1;
+	}
+	result = sigprocmask(SIG_BLOCK, &sigset, NULL);
+	if(result == -1) {
+		perror("sigprocmask");
+		return 1;
+	}
+
 	/* app loop */
 	for(;;) {
 		char *recvbuf;