4fca391ad16aac257662c8acb879d6b5df4e1d66
3 * Linux Trace Toolkit Netlink Control Library
5 * Controls the ltt-control kernel module through a netlink socket.
7 * Heavily inspired from libipq.c (iptables) made by
8 * James Morris <jmorris@intercode.com.au>
11 * Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
14 * This program is free software; you can redistribute it and/or modify
15 * it under the terms of the GNU General Public License as published by
16 * the Free Software Foundation; either version 2 of the License, or
17 * (at your option) any later version.
19 * This program is distributed in the hope that it will be useful,
20 * but WITHOUT ANY WARRANTY; without even the implied warranty of
21 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
22 * GNU General Public License for more details.
26 #include <libltt/libltt.h>
27 #include <linux/netlink.h>
31 /* Private interface */
52 #define LTTCTL_MAXERR LTTCTL_ERR_PROTOCOL
55 struct lttctl_errmap_t
{
59 { LTTCTL_ERR_NONE
, "Unknown error" },
60 { LTTCTL_ERR_IMPL
, "Implementation error" },
61 { LTTCTL_ERR_HANDLE
, "Unable to create netlink handle" },
62 { LTTCTL_ERR_SOCKET
, "Unable to create netlink socket" },
63 { LTTCTL_ERR_BIND
, "Unable to bind netlink socket" },
64 { LTTCTL_ERR_BUFFER
, "Unable to allocate buffer" },
65 { LTTCTL_ERR_RECV
, "Failed to receive netlink message" },
66 { LTTCTL_ERR_NLEOF
, "Received EOF on netlink socket" },
67 { LTTCTL_ERR_ADDRLEN
, "Invalid peer address length" },
68 { LTTCTL_ERR_STRUNC
, "Sent message truncated" },
69 { LTTCTL_ERR_RTRUNC
, "Received message truncated" },
70 { LTTCTL_ERR_NLRECV
, "Received error from netlink" },
71 { LTTCTL_ERR_SEND
, "Failed to send netlink message" },
72 { LTTCTL_ERR_SUPP
, "Operation not supported" },
73 { LTTCTL_ERR_RECVBUF
, "Receive buffer size invalid" },
74 { LTTCTL_ERR_TIMEOUT
, "Timeout"},
75 { LTTCTL_ERR_PROTOCOL
, "Invalid protocol specified" }
78 static int lttctl_errno
= LTTCTL_ERR_NONE
;
81 static ssize_t
lttctl_netlink_sendto(const struct lttctl_handle
*h
,
82 const void *msg
, size_t len
);
84 static ssize_t
lttctl_netlink_recvfrom(const struct lttctl_handle
*h
,
85 unsigned char *buf
, size_t len
,
88 static ssize_t
lttctl_netlink_sendmsg(const struct lttctl_handle
*h
,
89 const struct msghdr
*msg
,
92 static char *lttctl_strerror(int errcode
);
94 void lttctl_perror(const char *s
);
96 static ssize_t
lttctl_netlink_sendto(const struct lttctl_handle
*h
,
97 const void *msg
, size_t len
)
99 int status
= sendto(h
->fd
, msg
, len
, 0,
100 (struct sockaddr
*)&h
->peer
, sizeof(h
->peer
));
102 lttctl_errno
= LTTCTL_ERR_SEND
;
107 static ssize_t
lttctl_netlink_sendmsg(const struct lttctl_handle
*h
,
108 const struct msghdr
*msg
,
111 int status
= sendmsg(h
->fd
, msg
, flags
);
113 lttctl_errno
= LTTCTL_ERR_SEND
;
117 static ssize_t
lttctl_netlink_recvfrom(const struct lttctl_handle
*h
,
118 unsigned char *buf
, size_t len
,
122 struct nlmsghdr
*nlh
;
124 if (len
< sizeof(struct nlmsghdr
)) {
125 lttctl_errno
= LTTCTL_ERR_RECVBUF
;
126 lttctl_perror("Netlink recvfrom");
129 addrlen
= sizeof(h
->peer
);
137 /* non-block non-timeout */
141 tv
.tv_sec
= timeout
/ 1000000;
142 tv
.tv_usec
= timeout
% 1000000;
146 FD_SET(h
->fd
, &read_fds
);
147 ret
= select(h
->fd
+1, &read_fds
, NULL
, NULL
, &tv
);
149 if (errno
== EINTR
) {
153 lttctl_errno
= LTTCTL_ERR_RECV
;
154 lttctl_perror("Netlink recvfrom");
158 if (!FD_ISSET(h
->fd
, &read_fds
)) {
159 lttctl_errno
= LTTCTL_ERR_TIMEOUT
;
164 status
= recvfrom(h
->fd
, buf
, len
, 0,
165 (struct sockaddr
*)&h
->peer
, &addrlen
);
168 lttctl_errno
= LTTCTL_ERR_RECV
;
169 lttctl_perror("Netlink recvfrom");
172 if (addrlen
!= sizeof(h
->peer
)) {
173 lttctl_errno
= LTTCTL_ERR_RECV
;
174 lttctl_perror("Netlink recvfrom");
177 if (h
->peer
.nl_pid
!= 0) {
178 lttctl_errno
= LTTCTL_ERR_RECV
;
179 lttctl_perror("Netlink recvfrom");
183 lttctl_errno
= LTTCTL_ERR_NLEOF
;
184 lttctl_perror("Netlink recvfrom");
187 nlh
= (struct nlmsghdr
*)buf
;
188 if (nlh
->nlmsg_flags
& MSG_TRUNC
|| nlh
->nlmsg_len
> status
) {
189 lttctl_errno
= LTTCTL_ERR_RTRUNC
;
190 lttctl_perror("Netlink recvfrom");
199 static char *lttctl_strerror(int errcode
)
201 if (errcode
< 0 || errcode
> LTTCTL_MAXERR
)
202 errcode
= LTTCTL_ERR_IMPL
;
203 return lttctl_errmap
[errcode
].message
;
207 char *lttctl_errstr(void)
209 return lttctl_strerror(lttctl_errno
);
212 void lttctl_perror(const char *s
)
217 fputs("ERROR", stderr
);
219 fprintf(stderr
, ": %s", lttctl_errstr());
221 fprintf(stderr
, ": %s", strerror(errno
));
225 /* public interface */
228 * Create and initialise an lttctl handle.
230 struct lttctl_handle
*lttctl_create_handle(void)
233 struct lttctl_handle
*h
;
235 h
= (struct lttctl_handle
*)malloc(sizeof(struct lttctl_handle
));
237 lttctl_errno
= LTTCTL_ERR_HANDLE
;
238 lttctl_perror("Create handle");
242 memset(h
, 0, sizeof(struct lttctl_handle
));
244 h
->fd
= socket(PF_NETLINK
, SOCK_RAW
, NETLINK_LTT
);
247 lttctl_errno
= LTTCTL_ERR_SOCKET
;
248 lttctl_perror("Create handle");
251 memset(&h
->local
, 0, sizeof(struct sockaddr_nl
));
252 h
->local
.nl_family
= AF_NETLINK
;
253 h
->local
.nl_pid
= getpid();
254 h
->local
.nl_groups
= 0;
255 status
= bind(h
->fd
, (struct sockaddr
*)&h
->local
, sizeof(h
->local
));
257 lttctl_errno
= LTTCTL_ERR_BIND
;
258 lttctl_perror("Create handle");
261 memset(&h
->peer
, 0, sizeof(struct sockaddr_nl
));
262 h
->peer
.nl_family
= AF_NETLINK
;
264 h
->peer
.nl_groups
= 0;
267 /* Error condition */
277 * No error condition is checked here at this stage, but it may happen
278 * if/when reliable messaging is implemented.
280 int lttctl_destroy_handle(struct lttctl_handle
*h
)
290 int lttctl_create_trace(const struct lttctl_handle
*h
,
291 char *name
, enum trace_mode mode
)
297 lttctl_peer_msg_t msg
;
301 struct nlmsgerr nlerr
;
302 lttctl_peer_msg_t msg
;
305 memset(&req
, 0, sizeof(req
));
306 req
.nlh
.nlmsg_len
= NLMSG_LENGTH(sizeof(lttctl_peer_msg_t
));
307 req
.nlh
.nlmsg_flags
= NLM_F_REQUEST
|NLM_F_ACK
;
308 req
.nlh
.nlmsg_type
= LTTCTLM_CONTROL
;
309 req
.nlh
.nlmsg_pid
= h
->local
.nl_pid
;
310 req
.nlh
.nlmsg_seq
= 0;
312 strncpy(req
.msg
.trace_name
, name
, NAME_MAX
);
313 req
.msg
.op
= OP_CREATE
;
314 req
.msg
.args
.mode
= mode
;
316 err
= lttctl_netlink_sendto(h
, (void *)&req
, req
.nlh
.nlmsg_len
);
317 if(err
< 0) goto senderr
;
319 err
= lttctl_netlink_recvfrom(h
, (void*)&ack
, sizeof(ack
), 0);
320 if(err
< 0) goto senderr
;
322 err
= ack
.nlerr
.error
;
325 lttctl_perror("Create Trace Error");
332 lttctl_perror("Create Trace Error");
336 int lttctl_destroy_trace(const struct lttctl_handle
*h
,
341 lttctl_peer_msg_t msg
;
345 struct nlmsgerr nlerr
;
346 lttctl_peer_msg_t msg
;
350 memset(&req
, 0, sizeof(req
));
351 req
.nlh
.nlmsg_len
= NLMSG_LENGTH(sizeof(lttctl_peer_msg_t
));
352 req
.nlh
.nlmsg_flags
= NLM_F_REQUEST
;
353 req
.nlh
.nlmsg_type
= LTTCTLM_CONTROL
;
354 req
.nlh
.nlmsg_pid
= h
->local
.nl_pid
;
356 strncpy(req
.msg
.trace_name
, name
, NAME_MAX
);
357 req
.msg
.op
= OP_DESTROY
;
359 err
= lttctl_netlink_sendto(h
, (void *)&req
, req
.nlh
.nlmsg_len
);
360 if(err
< 0) goto senderr
;
362 err
= lttctl_netlink_recvfrom(h
, (void*)&ack
, sizeof(ack
), 0);
363 if(err
< 0) goto senderr
;
365 err
= ack
.nlerr
.error
;
368 lttctl_perror("Destroy Trace Channels Error");
375 lttctl_perror("Destroy Trace Channels Error");
380 int lttctl_start(const struct lttctl_handle
*h
,
385 lttctl_peer_msg_t msg
;
389 struct nlmsgerr nlerr
;
390 lttctl_peer_msg_t msg
;
395 memset(&req
, 0, sizeof(req
));
396 req
.nlh
.nlmsg_len
= NLMSG_LENGTH(sizeof(lttctl_peer_msg_t
));
397 req
.nlh
.nlmsg_flags
= NLM_F_REQUEST
;
398 req
.nlh
.nlmsg_type
= LTTCTLM_CONTROL
;
399 req
.nlh
.nlmsg_pid
= h
->local
.nl_pid
;
401 strncpy(req
.msg
.trace_name
, name
, NAME_MAX
);
402 req
.msg
.op
= OP_START
;
404 err
= lttctl_netlink_sendto(h
, (void *)&req
, req
.nlh
.nlmsg_len
);
405 if(err
< 0) goto senderr
;
407 err
= lttctl_netlink_recvfrom(h
, (void*)&ack
, sizeof(ack
), 0);
408 if(err
< 0) goto senderr
;
410 err
= ack
.nlerr
.error
;
413 lttctl_perror("Start Trace Error");
420 lttctl_perror("Start Trace Error");
425 int lttctl_stop(const struct lttctl_handle
*h
,
430 lttctl_peer_msg_t msg
;
434 struct nlmsgerr nlerr
;
435 lttctl_peer_msg_t msg
;
439 memset(&req
, 0, sizeof(req
));
440 req
.nlh
.nlmsg_len
= NLMSG_LENGTH(sizeof(lttctl_peer_msg_t
));
441 req
.nlh
.nlmsg_flags
= NLM_F_REQUEST
;
442 req
.nlh
.nlmsg_type
= LTTCTLM_CONTROL
;
443 req
.nlh
.nlmsg_pid
= h
->local
.nl_pid
;
445 strncpy(req
.msg
.trace_name
, name
, NAME_MAX
);
446 req
.msg
.op
= OP_STOP
;
448 err
= lttctl_netlink_sendto(h
, (void *)&req
, req
.nlh
.nlmsg_len
);
449 if(err
< 0) goto senderr
;
451 err
= lttctl_netlink_recvfrom(h
, (void*)&ack
, sizeof(ack
), 0);
452 if(err
< 0) goto senderr
;
454 err
= ack
.nlerr
.error
;
457 lttctl_perror("Stop Trace Error");
464 lttctl_perror("Stop Trace Error");
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