Add named pipe support to the pipe wrapper

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

diff --git a/src/common/pipe.c b/src/common/pipe.c
index 00211238e603ebc605f2bc63578bfa82652c0f0b..c8f00141574c3a6f11ce278a4c4a07d9cad1fa46 100644 (file)
--- a/src/common/pipe.c
+++ b/src/common/pipe.c
@@ -19,6 +19,8 @@
 #include <assert.h>
 #include <fcntl.h>
 #include <unistd.h>
+#include <sys/types.h>
+#include <sys/stat.h>
 
 #include <common/common.h>
 
@@ -112,6 +114,55 @@ 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++) {
+               ret = fcntl(pipe->fd[i], F_SETFD, flags);
+               if (ret < 0) {
+                       PERROR("fcntl lttng pipe %d", flags);
+                       goto end;
+               }
+       }
+end:
+       return ret;
+}
 
 /*
  * Open a new lttng pipe and set flags using fcntl().
@@ -124,9 +175,8 @@ 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;
        }
 
@@ -135,32 +185,75 @@ 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");
+               ret = fd_r;
+               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");
+               ret = fd_w;
+               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.
  *