X-Git-Url: https://git.lttng.org/?p=lttng-tools.git;a=blobdiff_plain;f=src%2Fcommon%2Fpipe.c;h=4fe45efada3e7dabfefd57b72b71cbcf167f2b03;hp=09e905de4fb64f1819a9cf5b3b8cdfc6281c015b;hb=b6151646d77a70cd8054543c07924c840646950b;hpb=6c1c0768320135c6936c371b09731851b508c023

diff --git a/src/common/pipe.c b/src/common/pipe.c
index 09e905de4..4fe45efad 100644
--- a/src/common/pipe.c
+++ b/src/common/pipe.c
@@ -15,11 +15,12 @@
  * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  */
 
-#define _GNU_SOURCE
 #define _LGPL_SOURCE
 #include <assert.h>
 #include <fcntl.h>
 #include <unistd.h>
+#include <sys/types.h>
+#include <sys/stat.h>
 
 #include <common/common.h>
 
@@ -113,20 +114,88 @@ end:
 	return ret_val;
 }
 
+static struct lttng_pipe *_pipe_create(void)
+{
+	int ret;
+	struct lttng_pipe *p;
+
+	p = zmalloc(sizeof(*p));
+	if (!p) {
+		PERROR("zmalloc pipe create");
+		goto end;
+	}
+	p->fd[0] = p->fd[1] = -1;
+
+	ret = pthread_mutex_init(&p->read_mutex, NULL);
+	if (ret) {
+		PERROR("pthread_mutex_init read lock pipe create");
+		goto error_destroy;
+	}
+	ret = pthread_mutex_init(&p->write_mutex, NULL);
+	if (ret) {
+		PERROR("pthread_mutex_init write lock pipe create");
+		goto error_destroy_rmutex;
+	}
+end:
+	return p;
+error_destroy_rmutex:
+	(void) pthread_mutex_destroy(&p->read_mutex);
+error_destroy:
+	free(p);
+	return NULL;
+}
+
+static int _pipe_set_flags(struct lttng_pipe *pipe, int flags)
+{
+	int i, ret = 0;
+
+	if (!flags) {
+		goto end;
+	}
+
+	for (i = 0; i < 2; i++) {
+		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;
+		}
+	}
+end:
+	return ret;
+}
 
 /*
  * Open a new lttng pipe and set flags using fcntl().
  *
  * Return a newly allocated lttng pipe on success or else NULL.
  */
+LTTNG_HIDDEN
 struct lttng_pipe *lttng_pipe_open(int flags)
 {
 	int ret;
 	struct lttng_pipe *p;
 
-	p = zmalloc(sizeof(*p));
+	p = _pipe_create();
 	if (!p) {
-		PERROR("zmalloc pipe open");
 		goto error;
 	}
 
@@ -135,37 +204,79 @@ struct lttng_pipe *lttng_pipe_open(int flags)
 		PERROR("lttng pipe");
 		goto error;
 	}
+	p->r_state = LTTNG_PIPE_STATE_OPENED;
+	p->w_state = LTTNG_PIPE_STATE_OPENED;
 
-	if (flags) {
-		int i;
-
-		for (i = 0; i < 2; i++) {
-			ret = fcntl(p->fd[i], F_SETFD, flags);
-			if (ret < 0) {
-				PERROR("fcntl lttng pipe %d", flags);
-				goto error;
-			}
-		}
+	ret = _pipe_set_flags(p, flags);
+	if (ret) {
+		goto error;
 	}
 
-	pthread_mutex_init(&p->read_mutex, NULL);
-	pthread_mutex_init(&p->write_mutex, NULL);
-	p->r_state = LTTNG_PIPE_STATE_OPENED;
-	p->w_state = LTTNG_PIPE_STATE_OPENED;
 	p->flags = flags;
 
 	return p;
-
 error:
 	lttng_pipe_destroy(p);
 	return NULL;
 }
 
+/*
+ * Open a new lttng pipe at path and set flags using fcntl().
+ *
+ * Return a newly allocated lttng pipe on success or else NULL.
+ */
+LTTNG_HIDDEN
+struct lttng_pipe *lttng_pipe_named_open(const char *path, mode_t mode,
+		int flags)
+{
+	int ret, fd_r, fd_w;
+	struct lttng_pipe *pipe;
+
+	pipe = _pipe_create();
+	if (!pipe) {
+		goto error;
+	}
+
+	ret = mkfifo(path, mode);
+	if (ret) {
+		PERROR("mkfifo");
+		goto error;
+	}
+
+	fd_r = open(path, O_RDONLY | O_NONBLOCK);
+	if (fd_r < 0) {
+		PERROR("open fifo");
+		goto error;
+	}
+	pipe->fd[0] = fd_r;
+	pipe->r_state = LTTNG_PIPE_STATE_OPENED;
+
+	fd_w = open(path, O_WRONLY | O_NONBLOCK);
+	if (fd_w < 0) {
+		PERROR("open fifo");
+		goto error;
+	}
+	pipe->fd[1] = fd_w;
+	pipe->w_state = LTTNG_PIPE_STATE_OPENED;
+
+	ret = _pipe_set_flags(pipe, flags);
+	if (ret) {
+		goto error;
+	}
+	pipe->flags = flags;
+
+	return pipe;
+error:
+	lttng_pipe_destroy(pipe);
+	return NULL;
+}
+
 /*
  * Close read side of a lttng pipe.
  *
  * Return 0 on success else a negative value.
  */
+LTTNG_HIDDEN
 int lttng_pipe_read_close(struct lttng_pipe *pipe)
 {
 	int ret;
@@ -185,6 +296,7 @@ int lttng_pipe_read_close(struct lttng_pipe *pipe)
  *
  * Return 0 on success else a negative value.
  */
+LTTNG_HIDDEN
 int lttng_pipe_write_close(struct lttng_pipe *pipe)
 {
 	int ret;
@@ -203,6 +315,7 @@ int lttng_pipe_write_close(struct lttng_pipe *pipe)
  *
  * Return 0 on success else a negative value.
  */
+LTTNG_HIDDEN
 int lttng_pipe_close(struct lttng_pipe *pipe)
 {
 	int ret, ret_val = 0;
@@ -225,6 +338,7 @@ int lttng_pipe_close(struct lttng_pipe *pipe)
 /*
  * Close and destroy a lttng pipe object. Finally, pipe is freed.
  */
+LTTNG_HIDDEN
 void lttng_pipe_destroy(struct lttng_pipe *pipe)
 {
 	int ret;
@@ -261,6 +375,7 @@ void lttng_pipe_destroy(struct lttng_pipe *pipe)
  * Return "count" on success. Return < count on error. errno can be used
  * to check the actual error.
  */
+LTTNG_HIDDEN
 ssize_t lttng_pipe_read(struct lttng_pipe *pipe, void *buf, size_t count)
 {
 	ssize_t ret;
@@ -286,6 +401,7 @@ error:
  * Return "count" on success. Return < count on error. errno can be used
  * to check the actual error.
  */
+LTTNG_HIDDEN
 ssize_t lttng_pipe_write(struct lttng_pipe *pipe, const void *buf,
 		size_t count)
 {
@@ -305,3 +421,69 @@ 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;
+}