X-Git-Url: http://git.liburcu.org/?a=blobdiff_plain;f=tags%2Fltt-control-0.51-12082008%2Fliblttctl%2Fliblttctl.c;fp=tags%2Fltt-control-0.51-12082008%2Fliblttctl%2Fliblttctl.c;h=61bca62e769e5f0a316e8cb550820acd0c09a415;hb=366ebe807eb22cd9480583f12eec527db0498987;hp=0000000000000000000000000000000000000000;hpb=efae29c4ba8f8842e83349a01b29ae5a8e3d721f;p=ltt-control.git diff --git a/tags/ltt-control-0.51-12082008/liblttctl/liblttctl.c b/tags/ltt-control-0.51-12082008/liblttctl/liblttctl.c new file mode 100644 index 0000000..61bca62 --- /dev/null +++ b/tags/ltt-control-0.51-12082008/liblttctl/liblttctl.c @@ -0,0 +1,491 @@ +/* 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 + * + * Copyright 2005 - + * Mathieu Desnoyers + * + * + * 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. + * + */ + +#ifdef HAVE_CONFIG_H +#include +#endif + +#include +#include +#include +#include +#include +#include +#include +#include + + + +/* 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[] = { + { LTTCTL_ERR_NONE, "Unknown error" }, + { LTTCTL_ERR_IMPL, "Implementation error" }, + { LTTCTL_ERR_HANDLE, "Unable to create netlink handle" }, + { LTTCTL_ERR_SOCKET, "Unable to create netlink socket" }, + { LTTCTL_ERR_BIND, "Unable to bind netlink socket" }, + { LTTCTL_ERR_BUFFER, "Unable to allocate buffer" }, + { LTTCTL_ERR_RECV, "Failed to receive netlink message" }, + { LTTCTL_ERR_NLEOF, "Received EOF on netlink socket" }, + { LTTCTL_ERR_ADDRLEN, "Invalid peer address length" }, + { LTTCTL_ERR_STRUNC, "Sent message truncated" }, + { LTTCTL_ERR_RTRUNC, "Received message truncated" }, + { LTTCTL_ERR_NLRECV, "Received error from netlink" }, + { LTTCTL_ERR_SEND, "Failed to send netlink message" }, + { LTTCTL_ERR_SUPP, "Operation not supported" }, + { LTTCTL_ERR_RECVBUF, "Receive buffer size invalid" }, + { LTTCTL_ERR_TIMEOUT, "Timeout"}, + { LTTCTL_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); + +void lttctl_perror(const char *s); + +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 nlmsghdr)) { + lttctl_errno = LTTCTL_ERR_RECVBUF; + lttctl_perror("Netlink recvfrom"); + 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) { + printf("eintr\n"); + return 0; + } else { + lttctl_errno = LTTCTL_ERR_RECV; + lttctl_perror("Netlink recvfrom"); + return -1; + } + } + if (!FD_ISSET(h->fd, &read_fds)) { + lttctl_errno = LTTCTL_ERR_TIMEOUT; + printf("timeout\n"); + return 0; + } + } + status = recvfrom(h->fd, buf, len, 0, + (struct sockaddr *)&h->peer, &addrlen); + + if (status < 0) { + lttctl_errno = LTTCTL_ERR_RECV; + lttctl_perror("Netlink recvfrom"); + return status; + } + if (addrlen != sizeof(h->peer)) { + lttctl_errno = LTTCTL_ERR_RECV; + lttctl_perror("Netlink recvfrom"); + return -1; + } + if (h->peer.nl_pid != 0) { + lttctl_errno = LTTCTL_ERR_RECV; + lttctl_perror("Netlink recvfrom"); + return -1; + } + if (status == 0) { + lttctl_errno = LTTCTL_ERR_NLEOF; + lttctl_perror("Netlink recvfrom"); + return -1; + } + nlh = (struct nlmsghdr *)buf; + if (nlh->nlmsg_flags & MSG_TRUNC || nlh->nlmsg_len > status) { + lttctl_errno = LTTCTL_ERR_RTRUNC; + lttctl_perror("Netlink recvfrom"); + 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; +} + + +char *lttctl_errstr(void) +{ + return lttctl_strerror(lttctl_errno); +} + +void lttctl_perror(const char *s) +{ + if (s) + fputs(s, stderr); + else + fputs("ERROR", stderr); + if (lttctl_errno) + fprintf(stderr, ": %s", lttctl_errstr()); + if (errno) + fprintf(stderr, ": %s", strerror(errno)); + fputc('\n', stderr); +} + +/* 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; + lttctl_perror("Create handle"); + goto alloc_error; + } + + 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; + lttctl_perror("Create handle"); + goto socket_error; + } + 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; + lttctl_perror("Create handle"); + goto bind_error; + } + 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; + + /* Error condition */ +bind_error: +socket_error: + close(h->fd); +alloc_error: + free(h); + return NULL; +} + +/* + * 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 lttctl_handle *h, + char *name, enum trace_mode mode, char *trace_type, + unsigned subbuf_size_low, unsigned n_subbufs_low, + unsigned subbuf_size_med, unsigned n_subbufs_med, + unsigned subbuf_size_high, unsigned n_subbufs_high) +{ + int err; + + struct { + struct nlmsghdr nlh; + lttctl_peer_msg_t msg; + } req; + struct { + struct nlmsghdr nlh; + struct nlmsgerr nlerr; + lttctl_peer_msg_t msg; + } ack; + + memset(&req, 0, sizeof(req)); + req.nlh.nlmsg_len = NLMSG_LENGTH(sizeof(lttctl_peer_msg_t)); + req.nlh.nlmsg_flags = NLM_F_REQUEST|NLM_F_ACK; + req.nlh.nlmsg_type = LTTCTLM_CONTROL; + req.nlh.nlmsg_pid = h->local.nl_pid; + req.nlh.nlmsg_seq = 0; + + strncpy(req.msg.trace_name, name, NAME_MAX); + strncpy(req.msg.trace_type, trace_type, NAME_MAX); + req.msg.op = OP_CREATE; + req.msg.args.new_trace.mode = mode; + req.msg.args.new_trace.subbuf_size_low = subbuf_size_low; + req.msg.args.new_trace.n_subbufs_low = n_subbufs_low; + req.msg.args.new_trace.subbuf_size_med = subbuf_size_med; + req.msg.args.new_trace.n_subbufs_med = n_subbufs_med; + req.msg.args.new_trace.subbuf_size_high = subbuf_size_high; + req.msg.args.new_trace.n_subbufs_high = n_subbufs_high; + + err = lttctl_netlink_sendto(h, (void *)&req, req.nlh.nlmsg_len); + if(err < 0) goto senderr; + + err = lttctl_netlink_recvfrom(h, (void*)&ack, sizeof(ack), 0); + if(err < 0) goto senderr; + + err = ack.nlerr.error; + if(err != 0) { + errno = err; + lttctl_perror("Create Trace Error"); + return err; + } + + return 0; + +senderr: + lttctl_perror("Create Trace Error"); + err = EPERM; + return err; +} + +int lttctl_destroy_trace(const struct lttctl_handle *h, + char *name) +{ + struct { + struct nlmsghdr nlh; + lttctl_peer_msg_t msg; + } req; + struct { + struct nlmsghdr nlh; + struct nlmsgerr nlerr; + lttctl_peer_msg_t msg; + } ack; + int err; + + memset(&req, 0, sizeof(req)); + req.nlh.nlmsg_len = NLMSG_LENGTH(sizeof(lttctl_peer_msg_t)); + 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; + + err = lttctl_netlink_sendto(h, (void *)&req, req.nlh.nlmsg_len); + if(err < 0) goto senderr; + + err = lttctl_netlink_recvfrom(h, (void*)&ack, sizeof(ack), 0); + if(err < 0) goto senderr; + + err = ack.nlerr.error; + if(err != 0) { + errno = err; + lttctl_perror("Destroy Trace Channels Error"); + return err; + } + + return 0; + +senderr: + lttctl_perror("Destroy Trace Channels Error"); + err = EPERM; + return err; + +} + +int lttctl_start(const struct lttctl_handle *h, + char *name) +{ + struct { + struct nlmsghdr nlh; + lttctl_peer_msg_t msg; + } req; + struct { + struct nlmsghdr nlh; + struct nlmsgerr nlerr; + lttctl_peer_msg_t msg; + } ack; + + int err; + + memset(&req, 0, sizeof(req)); + req.nlh.nlmsg_len = NLMSG_LENGTH(sizeof(lttctl_peer_msg_t)); + 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; + + err = lttctl_netlink_sendto(h, (void *)&req, req.nlh.nlmsg_len); + if(err < 0) goto senderr; + + err = lttctl_netlink_recvfrom(h, (void*)&ack, sizeof(ack), 0); + if(err < 0) goto senderr; + + err = ack.nlerr.error; + if(err != 0) { + errno = err; + lttctl_perror("Start Trace Error"); + return err; + } + + return 0; + +senderr: + err = EPERM; + lttctl_perror("Start Trace Error"); + return err; + +} + +int lttctl_stop(const struct lttctl_handle *h, + char *name) +{ + struct { + struct nlmsghdr nlh; + lttctl_peer_msg_t msg; + } req; + struct { + struct nlmsghdr nlh; + struct nlmsgerr nlerr; + lttctl_peer_msg_t msg; + } ack; + int err; + + memset(&req, 0, sizeof(req)); + req.nlh.nlmsg_len = NLMSG_LENGTH(sizeof(lttctl_peer_msg_t)); + 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; + + err = lttctl_netlink_sendto(h, (void *)&req, req.nlh.nlmsg_len); + if(err < 0) goto senderr; + + err = lttctl_netlink_recvfrom(h, (void*)&ack, sizeof(ack), 0); + if(err < 0) goto senderr; + + err = ack.nlerr.error; + if(err != 0) { + errno = err; + lttctl_perror("Stop Trace Error"); + return err; + } + + return 0; + +senderr: + err = EPERM; + lttctl_perror("Stop Trace Error"); + return err; +} +