start adding LGPL headers
[ust.git] / ustd / ustd.c
index 830d5e26441fe368b975b2c8b75fe44dd5e93060..b3af3c47efd3700fcb026247577ce8741782e3eb 100644 (file)
@@ -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
 #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;
-
-       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)
 {
@@ -64,12 +90,20 @@ int get_subbuffer(struct buffer_info *buf)
        int result;
 
        asprintf(&send_msg, "get_subbuffer %s", buf->name);
-       result = send_message(buf->pid, send_msg, &received_msg);
-       if(result < 0) {
-               ERR("get_subbuffer: send_message failed");
+       result = ustcomm_send_request(&buf->conn, send_msg, &received_msg);
+       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) {
@@ -81,10 +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);
@@ -106,7 +140,7 @@ int put_subbuffer(struct buffer_info *buf)
        int result;
 
        asprintf(&send_msg, "put_subbuffer %s %ld", buf->name, buf->consumed_old);
-       result = send_message(buf->pid, send_msg, &received_msg);
+       result = ustcomm_send_request(&buf->conn, send_msg, &received_msg);
        if(result < 0) {
                ERR("put_subbuffer: send_message failed");
                return -1;
@@ -122,16 +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;
@@ -159,15 +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);
@@ -176,15 +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;
 }
 
@@ -197,6 +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) {
@@ -207,24 +265,38 @@ int add_buffer(pid_t pid, char *bufname)
        buf->name = bufname;
        buf->pid = pid;
 
+       /* connect to app */
+       result = ustcomm_connect_app(buf->pid, &buf->conn);
+       if(result) {
+               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);
-       send_message(pid, 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);
-       send_message(pid, 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) {
@@ -236,7 +308,7 @@ int add_buffer(pid_t pid, char *bufname)
 
        /* get subbuf size */
        asprintf(&send_msg, "get_subbuf_size %s", buf->name);
-       send_message(pid, send_msg, &received_msg);
+       ustcomm_send_request(&buf->conn, send_msg, &received_msg);
        free(send_msg);
 
        result = sscanf(received_msg, "%d", &buf->subbuf_size);
@@ -253,20 +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;
@@ -276,6 +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) {
@@ -283,6 +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;
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