--- /dev/null
+/*
+ * Copyright (C) 2013 David Goulet <dgoulet@efficios.com>
+ *
+ * SPDX-License-Identifier: GPL-2.0-only
+ *
+ */
+
+#define _LGPL_SOURCE
+#include <fcntl.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+
+#include <common/common.h>
+
+#include "pipe.h"
+
+/*
+ * Lock read side of a pipe.
+ */
+static void lock_read_side(struct lttng_pipe *pipe)
+{
+ pthread_mutex_lock(&pipe->read_mutex);
+}
+
+/*
+ * Unlock read side of a pipe.
+ */
+static void unlock_read_side(struct lttng_pipe *pipe)
+{
+ pthread_mutex_unlock(&pipe->read_mutex);
+}
+
+/*
+ * Lock write side of a pipe.
+ */
+static void lock_write_side(struct lttng_pipe *pipe)
+{
+ pthread_mutex_lock(&pipe->write_mutex);
+}
+
+/*
+ * Unlock write side of a pipe.
+ */
+static void unlock_write_side(struct lttng_pipe *pipe)
+{
+ pthread_mutex_unlock(&pipe->write_mutex);
+}
+
+/*
+ * Internal function. Close read side of pipe WITHOUT locking the mutex.
+ *
+ * Return 0 on success else a negative errno from close(2).
+ */
+static int _pipe_read_close(struct lttng_pipe *pipe)
+{
+ int ret, ret_val = 0;
+
+ LTTNG_ASSERT(pipe);
+
+ if (!lttng_pipe_is_read_open(pipe)) {
+ goto end;
+ }
+
+ do {
+ ret = close(pipe->fd[0]);
+ } while (ret < 0 && errno == EINTR);
+ if (ret < 0) {
+ PERROR("close lttng read pipe");
+ ret_val = -errno;
+ }
+ pipe->r_state = LTTNG_PIPE_STATE_CLOSED;
+
+end:
+ return ret_val;
+}
+
+/*
+ * Internal function. Close write side of pipe WITHOUT locking the mutex.
+ *
+ * Return 0 on success else a negative errno from close(2).
+ */
+static int _pipe_write_close(struct lttng_pipe *pipe)
+{
+ int ret, ret_val = 0;
+
+ LTTNG_ASSERT(pipe);
+
+ if (!lttng_pipe_is_write_open(pipe)) {
+ goto end;
+ }
+
+ do {
+ ret = close(pipe->fd[1]);
+ } while (ret < 0 && errno == EINTR);
+ if (ret < 0) {
+ PERROR("close lttng write pipe");
+ ret_val = -errno;
+ }
+ pipe->w_state = LTTNG_PIPE_STATE_CLOSED;
+
+end:
+ return ret_val;
+}
+
+static struct lttng_pipe *_pipe_create(void)
+{
+ int ret;
+ struct lttng_pipe *p;
+
+ p = (lttng_pipe *) 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.
+ */
+struct lttng_pipe *lttng_pipe_open(int flags)
+{
+ int ret;
+ struct lttng_pipe *p;
+
+ p = _pipe_create();
+ if (!p) {
+ goto error;
+ }
+
+ ret = pipe(p->fd);
+ if (ret < 0) {
+ PERROR("lttng pipe");
+ goto error;
+ }
+ p->r_state = LTTNG_PIPE_STATE_OPENED;
+ p->w_state = LTTNG_PIPE_STATE_OPENED;
+
+ ret = _pipe_set_flags(p, flags);
+ if (ret) {
+ goto error;
+ }
+
+ 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.
+ */
+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.
+ */
+int lttng_pipe_read_close(struct lttng_pipe *pipe)
+{
+ int ret;
+
+ LTTNG_ASSERT(pipe);
+
+ /* Handle read side first. */
+ lock_read_side(pipe);
+ ret = _pipe_read_close(pipe);
+ unlock_read_side(pipe);
+
+ return ret;
+}
+
+/*
+ * Close write side of a lttng pipe.
+ *
+ * Return 0 on success else a negative value.
+ */
+int lttng_pipe_write_close(struct lttng_pipe *pipe)
+{
+ int ret;
+
+ LTTNG_ASSERT(pipe);
+
+ lock_write_side(pipe);
+ ret = _pipe_write_close(pipe);
+ unlock_write_side(pipe);
+
+ return ret;
+}
+
+/*
+ * Close both read and write side of a lttng pipe.
+ *
+ * Return 0 on success else a negative value.
+ */
+int lttng_pipe_close(struct lttng_pipe *pipe)
+{
+ int ret, ret_val = 0;
+
+ LTTNG_ASSERT(pipe);
+
+ ret = lttng_pipe_read_close(pipe);
+ if (ret < 0) {
+ ret_val = ret;
+ }
+
+ ret = lttng_pipe_write_close(pipe);
+ if (ret < 0) {
+ ret_val = ret;
+ }
+
+ return ret_val;
+}
+
+/*
+ * Close and destroy a lttng pipe object. Finally, pipe is freed.
+ */
+void lttng_pipe_destroy(struct lttng_pipe *pipe)
+{
+ int ret;
+
+ if (!pipe) {
+ return;
+ }
+
+ /*
+ * Destroy should *never* be called with a locked mutex. These must always
+ * succeed so we unlock them after the close pipe below.
+ */
+ ret = pthread_mutex_trylock(&pipe->read_mutex);
+ LTTNG_ASSERT(!ret);
+ ret = pthread_mutex_trylock(&pipe->write_mutex);
+ LTTNG_ASSERT(!ret);
+
+ /* Close pipes WITHOUT trying to lock the pipes. */
+ (void) _pipe_read_close(pipe);
+ (void) _pipe_write_close(pipe);
+
+ unlock_read_side(pipe);
+ unlock_write_side(pipe);
+
+ (void) pthread_mutex_destroy(&pipe->read_mutex);
+ (void) pthread_mutex_destroy(&pipe->write_mutex);
+
+ free(pipe);
+}
+
+/*
+ * Read on a lttng pipe and put the data in buf of at least size count.
+ *
+ * Return "count" on success. Return < count on error. errno can be used
+ * to check the actual error.
+ */
+ssize_t lttng_pipe_read(struct lttng_pipe *pipe, void *buf, size_t count)
+{
+ ssize_t ret;
+
+ LTTNG_ASSERT(pipe);
+ LTTNG_ASSERT(buf);
+
+ lock_read_side(pipe);
+ if (!lttng_pipe_is_read_open(pipe)) {
+ ret = -1;
+ errno = EBADF;
+ goto error;
+ }
+ ret = lttng_read(pipe->fd[0], buf, count);
+error:
+ unlock_read_side(pipe);
+ return ret;
+}
+
+/*
+ * Write on a lttng pipe using the data in buf and size of count.
+ *
+ * Return "count" on success. Return < count on error. errno can be used
+ * to check the actual error.
+ */
+ssize_t lttng_pipe_write(struct lttng_pipe *pipe, const void *buf,
+ size_t count)
+{
+ ssize_t ret;
+
+ LTTNG_ASSERT(pipe);
+ LTTNG_ASSERT(buf);
+
+ lock_write_side(pipe);
+ if (!lttng_pipe_is_write_open(pipe)) {
+ ret = -1;
+ errno = EBADF;
+ goto error;
+ }
+ ret = lttng_write(pipe->fd[1], buf, count);
+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.
+ */
+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.
+ */
+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;
+}
projects / lttng-tools.git / blobdiff