Fix multiple error handling for UST tracing

[lttng-tools.git] / liblttng-ustconsumer / lttng-ustconsumer.c

diff --git a/liblttng-ustconsumer/lttng-ustconsumer.c b/liblttng-ustconsumer/lttng-ustconsumer.c
index ed4a27c9da927d47ed52cadf129a6592d17fca48..8305b061a882fff9021037e1716ff32fb3f36935 100644 (file)
--- a/liblttng-ustconsumer/lttng-ustconsumer.c
+++ b/liblttng-ustconsumer/lttng-ustconsumer.c
@@ -33,6 +33,7 @@
 #include <lttng/lttng-ustconsumer.h>
 #include <lttng/ust-ctl.h>
 #include <lttngerr.h>
+#include <runas.h>
 
 extern struct lttng_consumer_global_data consumer_data;
 extern int consumer_poll_timeout;
@@ -209,13 +210,15 @@ int lttng_ustconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
                DBG("consumer_add_stream %s (%d,%d)", msg.u.stream.path_name,
                        fds[0], fds[1]);
                assert(msg.u.stream.output == LTTNG_EVENT_MMAP);
-               new_stream = consumer_allocate_stream(msg.u.stream.channel_key,
+               new_stream = consumer_allocate_stream(msg.u.channel.channel_key,
                                msg.u.stream.stream_key,
                                fds[0], fds[1],
                                msg.u.stream.state,
                                msg.u.stream.mmap_len,
                                msg.u.stream.output,
-                               msg.u.stream.path_name);
+                               msg.u.stream.path_name,
+                               msg.u.stream.uid,
+                               msg.u.stream.gid);
                if (new_stream == NULL) {
                        lttng_consumer_send_error(ctx, CONSUMERD_OUTFD_ERROR);
                        goto end;
@@ -234,6 +237,8 @@ int lttng_ustconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
        }
        case LTTNG_CONSUMER_UPDATE_STREAM:
        {
+               return -ENOSYS;
+#if 0
                if (ctx->on_update_stream != NULL) {
                        ret = ctx->on_update_stream(msg.u.stream.stream_key, msg.u.stream.state);
                        if (ret == 0) {
@@ -245,6 +250,7 @@ int lttng_ustconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
                        consumer_change_stream_state(msg.u.stream.stream_key,
                                msg.u.stream.state);
                }
+#endif
                break;
        }
        default:
@@ -272,11 +278,8 @@ int lttng_ustconsumer_allocate_channel(struct lttng_consumer_channel *chan)
        if (!chan->handle) {
                return -ENOMEM;
        }
-       /*
-        * The channel fds are passed to ustctl, we only keep a copy.
-        */
-       chan->shm_fd_is_copy = 1;
        chan->wait_fd_is_copy = 1;
+       chan->shm_fd = -1;
 
        return 0;
 }
@@ -284,6 +287,7 @@ int lttng_ustconsumer_allocate_channel(struct lttng_consumer_channel *chan)
 void lttng_ustconsumer_on_stream_hangup(struct lttng_consumer_stream *stream)
 {
        ustctl_flush_buffer(stream->chan->handle, stream->buf, 0);
+       stream->hangup_flush_done = 1;
 }
 
 void lttng_ustconsumer_del_channel(struct lttng_consumer_channel *chan)
@@ -306,15 +310,14 @@ int lttng_ustconsumer_allocate_stream(struct lttng_consumer_stream *stream)
        stream->buf = ustctl_open_stream_read(stream->chan->handle, stream->cpu);
        if (!stream->buf)
                return -EBUSY;
+       /* ustctl_open_stream_read has closed the shm fd. */
+       stream->wait_fd_is_copy = 1;
+       stream->shm_fd = -1;
+
        stream->mmap_base = ustctl_get_mmap_base(stream->chan->handle, stream->buf);
        if (!stream->mmap_base) {
                return -EINVAL;
        }
-       /*
-        * The stream fds are passed to ustctl, we only keep a copy.
-        */
-       stream->shm_fd_is_copy = 1;
-       stream->wait_fd_is_copy = 1;
 
        return 0;
 }
@@ -340,12 +343,14 @@ int lttng_ustconsumer_read_subbuffer(struct lttng_consumer_stream *stream,
                stream->wait_fd, stream->key);
 
        /* We can consume the 1 byte written into the wait_fd by UST */
-       do {
-               readlen = read(stream->wait_fd, &dummy, 1);
-       } while (readlen == -1 && errno == -EINTR);
-       if (readlen == -1) {
-               ret = readlen;
-               goto end;
+       if (!stream->hangup_flush_done) {
+               do {
+                       readlen = read(stream->wait_fd, &dummy, 1);
+               } while (readlen == -1 && errno == -EINTR);
+               if (readlen == -1) {
+                       ret = readlen;
+                       goto end;
+               }
        }
 
        buf = stream->buf;
@@ -353,7 +358,7 @@ int lttng_ustconsumer_read_subbuffer(struct lttng_consumer_stream *stream,
        /* Get the next subbuffer */
        err = ustctl_get_next_subbuf(handle, buf);
        if (err != 0) {
-               ret = errno;
+               ret = -ret;     /* ustctl_get_next_subbuf returns negative, caller expect positive. */
                /*
                 * This is a debug message even for single-threaded consumer,
                 * because poll() have more relaxed criterions than get subbuf,
@@ -367,11 +372,7 @@ int lttng_ustconsumer_read_subbuffer(struct lttng_consumer_stream *stream,
        assert(stream->output == LTTNG_EVENT_MMAP);
        /* read the used subbuffer size */
        err = ustctl_get_padded_subbuf_size(handle, buf, &len);
-       if (err != 0) {
-               ret = errno;
-               perror("Getting sub-buffer len failed.");
-               goto end;
-       }
+       assert(err == 0);
        /* write the subbuffer to the tracefile */
        ret = lttng_consumer_on_read_subbuffer_mmap(ctx, stream, len);
        if (ret < 0) {
@@ -382,16 +383,7 @@ int lttng_ustconsumer_read_subbuffer(struct lttng_consumer_stream *stream,
                ERR("Error writing to tracefile");
        }
        err = ustctl_put_next_subbuf(handle, buf);
-       if (err != 0) {
-               ret = errno;
-               if (errno == EFAULT) {
-                       perror("Error in unreserving sub buffer\n");
-               } else if (errno == EIO) {
-                       /* Should never happen with newer LTTng versions */
-                       perror("Reader has been pushed by the writer, last sub-buffer corrupted.");
-               }
-               goto end;
-       }
+       assert(err == 0);
 end:
        return ret;
 }
@@ -402,8 +394,10 @@ int lttng_ustconsumer_on_recv_stream(struct lttng_consumer_stream *stream)
 
        /* Opening the tracefile in write mode */
        if (stream->path_name != NULL) {
-               ret = open(stream->path_name,
-                               O_WRONLY|O_CREAT|O_TRUNC, S_IRWXU|S_IRWXG|S_IRWXO);
+               ret = open_run_as(stream->path_name,
+                               O_WRONLY|O_CREAT|O_TRUNC,
+                               S_IRWXU|S_IRWXG|S_IRWXO,
+                               stream->uid, stream->gid);
                if (ret < 0) {
                        ERR("Opening %s", stream->path_name);
                        perror("open");