--- /dev/null
+/* libltt
+ *
+ * Linux Trace Toolkit Netlink Control Library
+ *
+ * Controls the ltt-control kernel module through a netlink socket.
+ *
+ * Heavily inspired from libipq.c (iptables) made by
+ * James Morris <jmorris@intercode.com.au>
+ *
+ * Copyright 2005 -
+ * Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
+ *
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * 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.
+ *
+ */
+
+#include <ltt/libltt.h>
+
+
+/* Private interface */
+
+enum {
+ LTTCTL_ERR_NONE = 0,
+ LTTCTL_ERR_IMPL,
+ LTTCTL_ERR_HANDLE,
+ LTTCTL_ERR_SOCKET,
+ LTTCTL_ERR_BIND,
+ LTTCTL_ERR_BUFFER,
+ LTTCTL_ERR_RECV,
+ LTTCTL_ERR_NLEOF,
+ LTTCTL_ERR_ADDRLEN,
+ LTTCTL_ERR_STRUNC,
+ LTTCTL_ERR_RTRUNC,
+ LTTCTL_ERR_NLRECV,
+ LTTCTL_ERR_SEND,
+ LTTCTL_ERR_SUPP,
+ LTTCTL_ERR_RECVBUF,
+ LTTCTL_ERR_TIMEOUT,
+ LTTCTL_ERR_PROTOCOL
+};
+#define LTTCTL_MAXERR LTTCTL_ERR_PROTOCOL
+
+
+struct lttctl_errmap_t {
+ int errcode;
+ char *message;
+} lttctl_errmap[] = {
+ { IPQ_ERR_NONE, "Unknown error" },
+ { IPQ_ERR_IMPL, "Implementation error" },
+ { IPQ_ERR_HANDLE, "Unable to create netlink handle" },
+ { IPQ_ERR_SOCKET, "Unable to create netlink socket" },
+ { IPQ_ERR_BIND, "Unable to bind netlink socket" },
+ { IPQ_ERR_BUFFER, "Unable to allocate buffer" },
+ { IPQ_ERR_RECV, "Failed to receive netlink message" },
+ { IPQ_ERR_NLEOF, "Received EOF on netlink socket" },
+ { IPQ_ERR_ADDRLEN, "Invalid peer address length" },
+ { IPQ_ERR_STRUNC, "Sent message truncated" },
+ { IPQ_ERR_RTRUNC, "Received message truncated" },
+ { IPQ_ERR_NLRECV, "Received error from netlink" },
+ { IPQ_ERR_SEND, "Failed to send netlink message" },
+ { IPQ_ERR_SUPP, "Operation not supported" },
+ { IPQ_ERR_RECVBUF, "Receive buffer size invalid" },
+ { IPQ_ERR_TIMEOUT, "Timeout"},
+ { IPQ_ERR_PROTOCOL, "Invalid protocol specified" }
+};
+
+static int lttctl_errno = LTTCTL_ERR_NONE;
+
+
+static ssize_t lttctl_netlink_sendto(const struct lttctl_handle *h,
+ const void *msg, size_t len);
+
+static ssize_t lttctl_netlink_recvfrom(const struct lttctl_handle *h,
+ unsigned char *buf, size_t len,
+ int timeout);
+
+static ssize_t lttctl_netlink_sendmsg(const struct lttctl_handle *h,
+ const struct msghdr *msg,
+ unsigned int flags);
+
+static char *lttctl_strerror(int errcode);
+
+static ssize_t lttctl_netlink_sendto(const struct lttctl_handle *h,
+ const void *msg, size_t len)
+{
+ int status = sendto(h->fd, msg, len, 0,
+ (struct sockaddr *)&h->peer, sizeof(h->peer));
+ if (status < 0)
+ lttctl_errno = LTTCTL_ERR_SEND;
+ return status;
+}
+
+static ssize_t lttctl_netlink_sendmsg(const struct lttctl_handle *h,
+ const struct msghdr *msg,
+ unsigned int flags)
+{
+ int status = sendmsg(h->fd, msg, flags);
+ if (status < 0)
+ lttctl_errno = LTTCTL_ERR_SEND;
+ return status;
+}
+
+static ssize_t lttctl_netlink_recvfrom(const struct lttctl_handle *h,
+ unsigned char *buf, size_t len,
+ int timeout)
+{
+ int addrlen, status;
+ struct nlmsghdr *nlh;
+
+ if (len < sizeof(struct nlmsgerr)) {
+ lttctl_errno = LTTCTL_ERR_RECVBUF;
+ return -1;
+ }
+ addrlen = sizeof(h->peer);
+
+ if (timeout != 0) {
+ int ret;
+ struct timeval tv;
+ fd_set read_fds;
+
+ if (timeout < 0) {
+ /* non-block non-timeout */
+ tv.tv_sec = 0;
+ tv.tv_usec = 0;
+ } else {
+ tv.tv_sec = timeout / 1000000;
+ tv.tv_usec = timeout % 1000000;
+ }
+
+ FD_ZERO(&read_fds);
+ FD_SET(h->fd, &read_fds);
+ ret = select(h->fd+1, &read_fds, NULL, NULL, &tv);
+ if (ret < 0) {
+ if (errno == EINTR) {
+ return 0;
+ } else {
+ lttctl_errno = lttctl_ERR_RECV;
+ return -1;
+ }
+ }
+ if (!FD_ISSET(h->fd, &read_fds)) {
+ lttctl_errno = lttctl_ERR_TIMEOUT;
+ return 0;
+ }
+ }
+ status = recvfrom(h->fd, buf, len, 0,
+ (struct sockaddr *)&h->peer, &addrlen);
+ if (status < 0) {
+ lttctl_errno = LTTCTL_ERR_RECV;
+ return status;
+ }
+ if (addrlen != sizeof(h->peer)) {
+ lttctl_errno = LTTCTL_ERR_RECV;
+ return -1;
+ }
+ if (h->peer.nl_pid != 0) {
+ lttctl_errno = LTTCTL_ERR_RECV;
+ return -1;
+ }
+ if (status == 0) {
+ lttctl_errno = LTTCTL_ERR_NLEOF;
+ return -1;
+ }
+ nlh = (struct nlmsghdr *)buf;
+ if (nlh->nlmsg_flags & MSG_TRUNC || nlh->nlmsg_len > status) {
+ lttctl_errno = LTTCTL_ERR_RTRUNC;
+ return -1;
+ }
+ return status;
+}
+
+
+static char *lttctl_strerror(int errcode)
+{
+ if (errcode < 0 || errcode > LTTCTL_MAXERR)
+ errcode = LTTCTL_ERR_IMPL;
+ return lttctl_errmap[errcode].message;
+}
+
+
+
+/* public interface */
+
+/*
+ * Create and initialise an lttctl handle.
+ */
+struct lttctl_handle *lttctl_create_handle(void)
+{
+ int status;
+ struct lttctl_handle *h;
+
+ h = (struct lttctl_handle *)malloc(sizeof(struct lttctl_handle));
+ if (h == NULL) {
+ lttctl_errno = lttctl_ERR_HANDLE;
+ return NULL;
+ }
+
+ memset(h, 0, sizeof(struct lttctl_handle));
+
+ h->fd = socket(PF_NETLINK, SOCK_RAW, NETLINK_LTT);
+
+ if (h->fd == -1) {
+ lttctl_errno = LTTCTL_ERR_SOCKET;
+ close(h->fd);
+ free(h);
+ return NULL;
+ }
+ memset(&h->local, 0, sizeof(struct sockaddr_nl));
+ h->local.nl_family = AF_NETLINK;
+ h->local.nl_pid = getpid();
+ h->local.nl_groups = 0;
+ status = bind(h->fd, (struct sockaddr *)&h->local, sizeof(h->local));
+ if (status == -1) {
+ lttctl_errno = LTTCTL_ERR_BIND;
+ close(h->fd);
+ free(h);
+ return NULL;
+ }
+ memset(&h->peer, 0, sizeof(struct sockaddr_nl));
+ h->peer.nl_family = AF_NETLINK;
+ h->peer.nl_pid = 0;
+ h->peer.nl_groups = 0;
+ return h;
+}
+
+/*
+ * No error condition is checked here at this stage, but it may happen
+ * if/when reliable messaging is implemented.
+ */
+int lttctl_destroy_handle(struct lttctl_handle *h)
+{
+ if (h) {
+ close(h->fd);
+ free(h);
+ }
+ return 0;
+}
+
+
+int lttctl_create_trace(const struct ipq_handle *h,
+ char *name, enum trace_mode mode)
+{
+ struct {
+ struct nlmsghdr nlh;
+ lttctl_peer_msg_t msg;
+ } req;
+
+ memset(&req, 0, sizeof(req));
+ req.nlh.nlmsg_len = NLMSG_LENGTH(sizeof(req));
+ req.nlh.nlmsg_flags = NLM_F_REQUEST;
+ req.nlh.nlmsg_type = LTTCTLM_CONTROL;
+ req.nlh.nlmsg_pid = h->local.nl_pid;
+
+ strncpy(req.msg.trace_name, name, NAME_MAX);
+ req.msg.op = OP_CREATE;
+ req.msg.args.mode = mode;
+
+ return lttctl_netlink_sendto(h, (void *)&req, req.nlh.nlmsg_len);
+}
+
+int lttctl_destroy_trace(const struct ipq_handle *h,
+ char *name)
+{
+ struct {
+ struct nlmsghdr nlh;
+ lttctl_peer_msg_t msg;
+ } req;
+
+ memset(&req, 0, sizeof(req));
+ req.nlh.nlmsg_len = NLMSG_LENGTH(sizeof(req));
+ req.nlh.nlmsg_flags = NLM_F_REQUEST;
+ req.nlh.nlmsg_type = LTTCTLM_CONTROL;
+ req.nlh.nlmsg_pid = h->local.nl_pid;
+
+ strncpy(req.msg.trace_name, name, NAME_MAX);
+ req.msg.op = OP_DESTROY;
+
+ return lttctl_netlink_sendto(h, (void *)&req, req.nlh.nlmsg_len);
+}
+
+int lttctl_start(const struct ipq_handle *h,
+ char *name)
+{
+ struct {
+ struct nlmsghdr nlh;
+ lttctl_peer_msg_t msg;
+ } req;
+
+ memset(&req, 0, sizeof(req));
+ req.nlh.nlmsg_len = NLMSG_LENGTH(sizeof(req));
+ req.nlh.nlmsg_flags = NLM_F_REQUEST;
+ req.nlh.nlmsg_type = LTTCTLM_CONTROL;
+ req.nlh.nlmsg_pid = h->local.nl_pid;
+
+ strncpy(req.msg.trace_name, name, NAME_MAX);
+ req.msg.op = OP_START;
+
+ return lttctl_netlink_sendto(h, (void *)&req, req.nlh.nlmsg_len);
+}
+
+int lttctl_stop(const struct ipq_handle *h,
+ char *name)
+{
+ struct {
+ struct nlmsghdr nlh;
+ lttctl_peer_msg_t msg;
+ } req;
+
+ memset(&req, 0, sizeof(req));
+ req.nlh.nlmsg_len = NLMSG_LENGTH(sizeof(req));
+ req.nlh.nlmsg_flags = NLM_F_REQUEST;
+ req.nlh.nlmsg_type = LTTCTLM_CONTROL;
+ req.nlh.nlmsg_pid = h->local.nl_pid;
+
+ strncpy(req.msg.trace_name, name, NAME_MAX);
+ req.msg.op = OP_STOP;
+
+ return lttctl_netlink_sendto(h, (void *)&req, req.nlh.nlmsg_len);
+}
projects / lttv.git / commitdiff
