trigger: use condition and action ref counting to ease internal objects management

[lttng-tools.git] / src / common / pipe.c

diff --git a/src/common/pipe.c b/src/common/pipe.c
index c8f00141574c3a6f11ce278a4c4a07d9cad1fa46..868c1f3de839dd71847604062ed063b0acb31b1d 100644 (file)
--- a/src/common/pipe.c
+++ b/src/common/pipe.c
@@ -1,18 +1,8 @@
 /*
- * Copyright (C) 2013 - David Goulet <dgoulet@efficios.com>
+ * Copyright (C) 2013 David Goulet <dgoulet@efficios.com>
  *
- * This program is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License, version 2 only, as
- * published by the Free Software Foundation.
+ * SPDX-License-Identifier: GPL-2.0-only
  *
- * This program 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.
- *
- * You should have received a copy of the GNU General Public License along with
- * this program; if not, write to the Free Software Foundation, Inc., 51
- * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  */
 
 #define _LGPL_SOURCE
@@ -154,9 +144,28 @@ static int _pipe_set_flags(struct lttng_pipe *pipe, int flags)
        }
 
        for (i = 0; i < 2; i++) {
-               ret = fcntl(pipe->fd[i], F_SETFD, flags);
-               if (ret < 0) {
-                       PERROR("fcntl lttng pipe %d", flags);
+               if (flags & O_NONBLOCK) {
+                       ret = fcntl(pipe->fd[i], F_SETFL, O_NONBLOCK);
+                       if (ret < 0) {
+                               PERROR("fcntl lttng pipe %d", flags);
+                               goto end;
+                       }
+               }
+               if (flags & FD_CLOEXEC) {
+                       ret = fcntl(pipe->fd[i], F_SETFD, FD_CLOEXEC);
+                       if (ret < 0) {
+                               PERROR("fcntl lttng pipe %d", flags);
+                               goto end;
+                       }
+               }
+               /*
+                * We only check for O_NONBLOCK or FD_CLOEXEC, if another flag is
+                * needed, we can add it, but for now just make sure we don't make
+                * mistakes with the parameters we pass.
+                */
+               if (!(flags & O_NONBLOCK) && !(flags & FD_CLOEXEC)) {
+                       fprintf(stderr, "Unsupported flag\n");
+                       ret = -1;
                        goto end;
                }
        }
@@ -227,7 +236,6 @@ struct lttng_pipe *lttng_pipe_named_open(const char *path, mode_t mode,
        fd_r = open(path, O_RDONLY | O_NONBLOCK);
        if (fd_r < 0) {
                PERROR("open fifo");
-               ret = fd_r;
                goto error;
        }
        pipe->fd[0] = fd_r;
@@ -236,7 +244,6 @@ struct lttng_pipe *lttng_pipe_named_open(const char *path, mode_t mode,
        fd_w = open(path, O_WRONLY | O_NONBLOCK);
        if (fd_w < 0) {
                PERROR("open fifo");
-               ret = fd_w;
                goto error;
        }
        pipe->fd[1] = fd_w;
@@ -404,3 +411,69 @@ error:
        unlock_write_side(pipe);
        return ret;
 }
+
+/*
+ * Return and release the read end of the pipe.
+ *
+ * This call transfers the ownership of the read fd of the underlying pipe
+ * to the caller if it is still open.
+ *
+ * Returns the fd of the read end of the pipe, or -1 if it was already closed or
+ * released.
+ */
+LTTNG_HIDDEN
+int lttng_pipe_release_readfd(struct lttng_pipe *pipe)
+{
+       int ret;
+
+       if (!pipe) {
+               ret = -1;
+               goto end;
+       }
+
+       lock_read_side(pipe);
+       if (!lttng_pipe_is_read_open(pipe)) {
+               ret = -1;
+               goto end_unlock;
+       }
+       ret = pipe->fd[0];
+       pipe->fd[0] = -1;
+       pipe->r_state = LTTNG_PIPE_STATE_CLOSED;
+end_unlock:
+       unlock_read_side(pipe);
+end:
+       return ret;
+}
+
+/*
+ * Return and release the write end of the pipe.
+ *
+ * This call transfers the ownership of the write fd of the underlying pipe
+ * to the caller if it is still open.
+ *
+ * Returns the fd of the write end of the pipe, or -1 if it was alwritey closed
+ * or released.
+ */
+LTTNG_HIDDEN
+int lttng_pipe_release_writefd(struct lttng_pipe *pipe)
+{
+       int ret;
+
+       if (!pipe) {
+               ret = -1;
+               goto end;
+       }
+
+       lock_write_side(pipe);
+       if (!lttng_pipe_is_write_open(pipe)) {
+               ret = -1;
+               goto end_unlock;
+       }
+       ret = pipe->fd[1];
+       pipe->fd[1] = -1;
+       pipe->w_state = LTTNG_PIPE_STATE_CLOSED;
+end_unlock:
+       unlock_write_side(pipe);
+end:
+       return ret;
+}