CSE2410 Fall 2014 Bounce

/* Copyright Joyent, Inc. and other Node contributors.

 *

 * Permission is hereby granted, free of charge, to any person obtaining a

 * copy of this software and associated documentation files (the

 * "Software"), to deal in the Software without restriction, including

 * without limitation the rights to use, copy, modify, merge, publish,

 * distribute, sublicense, and/or sell copies of the Software, and to permit

 * persons to whom the Software is furnished to do so, subject to the

 * following conditions:

 *

 * The above copyright notice and this permission notice shall be included

 * in all copies or substantial portions of the Software.

 *

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS

 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF

 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN

 * NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,

 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR

 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE

 * USE OR OTHER DEALINGS IN THE SOFTWARE.

 */

/*

 * This is the DTrace library file for the node provider, which includes

 * the necessary translators to get from the args[] to something useful.

 * Be warned:  the mechanics here are seriously ugly -- and one must always

 * keep in mind that clean abstractions often require filthy systems.

 */

#pragma D depends_on library procfs.d

typedef struct {

	int32_t fd;

	int32_t port;

	uint32_t remote;

	uint32_t buffered;

} node_dtrace_connection_t;

typedef struct {

	int32_t fd;

	int32_t port;

	uint64_t remote;

	uint32_t buffered;

} node_dtrace_connection64_t;

typedef struct {

	int fd;

	string remoteAddress;

	int remotePort;

	int bufferSize;

} node_connection_t;

translator node_connection_t <node_dtrace_connection_t *nc> {

	fd = *(int32_t *)copyin((uintptr_t)&nc->fd, sizeof (int32_t));

	remotePort =

	    *(int32_t *)copyin((uintptr_t)&nc->port, sizeof (int32_t));

	remoteAddress = curpsinfo->pr_dmodel == PR_MODEL_ILP32 ?

	    copyinstr((uintptr_t)*(uint32_t *)copyin((uintptr_t)&nc->remote,

	    sizeof (int32_t))) :

	    copyinstr((uintptr_t)*(uint64_t *)copyin((uintptr_t)

	    &((node_dtrace_connection64_t *)nc)->remote, sizeof (int64_t)));

	bufferSize = curpsinfo->pr_dmodel == PR_MODEL_ILP32 ?

	    *(uint32_t *)copyin((uintptr_t)&nc->buffered, sizeof (int32_t)) :

	    *(uint32_t *)copyin((uintptr_t)

	    &((node_dtrace_connection64_t *)nc)->buffered, sizeof (int32_t));

};

/*

 * 32-bit and 64-bit structures received from node for HTTP client request

 * probe.

 */

typedef struct {

	uint32_t url;

	uint32_t method;

} node_dtrace_http_client_request_t;

typedef struct {

	uint64_t url;

	uint64_t method;

} node_dtrace_http_client_request64_t;

/*

 * The following structures are never used directly, but must exist to bind the

 * types specified in the provider to the translators defined here.

 * Ultimately, they always get cast to a more specific type inside the

 * translator.  To add to the confusion, the DTrace compiler does not allow

 * declaring two translators with the same destination type if the source types

 * are structures with the same size (because libctf says they're compatible,

 * so dtrace considers them equivalent).  Since we must define translators from

 * node_dtrace_http_client_request_t (above), node_dtrace_http_request_t, and

 * node_dtrace_http_server_request_t (both below), each of these three structs

 * must be declared with a different size.

 */

typedef struct {

	uint32_t version;

	uint64_t dummy1;

} node_dtrace_http_request_t;

typedef struct {

	uint32_t version;

	uint64_t dummy2;

	uint64_t dummy3;

} node_dtrace_http_server_request_t;

/*

 * Actual 32-bit and 64-bit, v0 and v1 structures received from node for the

 * HTTP server request probe.

 */

typedef struct {

	uint32_t url;

	uint32_t method;

} node_dtrace_http_server_request_v0_t;

typedef struct {

	uint32_t version;

	uint32_t url;

	uint32_t method;

	uint32_t forwardedFor;

} node_dtrace_http_server_request_v1_t;

typedef struct {

	uint64_t url;

	uint64_t method;

} node_dtrace_http_server_request64_v0_t;

typedef struct {

	uint32_t version;

	uint32_t pad;

	uint64_t url;

	uint64_t method;

	uint64_t forwardedFor;

} node_dtrace_http_server_request64_v1_t;

/*

 * In the end, both client and server request probes from both old and new

 * binaries translate their arguments to node_http_request_t, which is what the

 * user's D script ultimately sees.

 */

typedef struct {

	string url;

	string method;

	string forwardedFor;

} node_http_request_t;

/*

 * The following translators are particularly filthy for reasons of backwards

 * compatibility.  Stable versions of node prior to 0.6 used a single

 * http_request struct with fields for "url" and "method" for both client and

 * server probes.  0.6 added a "forwardedFor" field intended for the server

 * probe only, and the http_request struct passed by the application was split

 * first into client_http_request and server_http_request and the latter was

 * again split for v0 (the old struct) and v1.

 *

 * To distinguish the binary representations of the two versions of these

 * structs, the new version prepends a "version" member (where the old one has

 * a "url" pointer).  Each field that we're translating below first switches on

 * the value of this "version" field: if it's larger than 4096, we know we must

 * be looking at the "url" pointer of the older structure version.  Otherwise,

 * we must be looking at the new version.  Besides this, we have the usual

 * switch based on the userland process data model.  This would all be simpler

 * with macros, but those aren't available in D library files since we cannot

 * rely on cpp being present at runtime.

 *

 * In retrospect, the versioning bit might have been unnecessary since the type

 * of the object passed in should allow DTrace to select which translator to

 * use.  However, DTrace does sometimes use translators whose source types

 * don't quite match, and since we know this versioning logic works, we just

 * leave it alone.  Each of the translators below is functionally identical

 * (except that the client -> client translator doesn't bother translating

 * forwardedFor) and should actually work with any version of any of the client

 * or server structs transmitted by the application up to this point.

 */

/*

 * Translate from node_dtrace_http_server_request_t (received from node 0.6 and

 * later versions) to node_http_request_t.

 */

translator node_http_request_t <node_dtrace_http_server_request_t *nd> {

	url = (*(uint32_t *)copyin((uintptr_t)(uint32_t *)nd,

		sizeof (uint32_t))) >= 4096 ?

	    (curpsinfo->pr_dmodel == PR_MODEL_ILP32 ?

		copyinstr(*(uint32_t *)copyin((uintptr_t)

		    &((node_dtrace_http_server_request_v0_t *)nd)->url,

		    sizeof (uint32_t))) :

		copyinstr(*(uint64_t *)copyin((uintptr_t)

		    &((node_dtrace_http_server_request64_v0_t *)nd)->url,

		    sizeof (uint64_t)))) :

	    (curpsinfo->pr_dmodel == PR_MODEL_ILP32 ?

		copyinstr(*(uint32_t *)copyin((uintptr_t)

		    &((node_dtrace_http_server_request_v1_t *)nd)->url,

		    sizeof (uint32_t))) :

		copyinstr(*(uint64_t *)copyin((uintptr_t)

		    &((node_dtrace_http_server_request64_v1_t *)nd)->url,

		    sizeof (uint64_t))));

	method = (*(uint32_t *)copyin((uintptr_t)(uint32_t *)nd,

		sizeof (uint32_t))) >= 4096 ?

	    (curpsinfo->pr_dmodel == PR_MODEL_ILP32 ?

		copyinstr(*(uint32_t *)copyin((uintptr_t)

		    &((node_dtrace_http_server_request_v0_t *)nd)->method,

		    sizeof (uint32_t))) :

		copyinstr(*(uint64_t *)copyin((uintptr_t)

		    &((node_dtrace_http_server_request64_v0_t *)nd)->method,

		    sizeof (uint64_t)))) :

	    (curpsinfo->pr_dmodel == PR_MODEL_ILP32 ?

		copyinstr(*(uint32_t *)copyin((uintptr_t)

		    &((node_dtrace_http_server_request_v1_t *)nd)->method,

		    sizeof (uint32_t))) :

		copyinstr(*(uint64_t *)copyin((uintptr_t)

		    &((node_dtrace_http_server_request64_v1_t *)nd)->method,

		    sizeof (uint64_t))));

	forwardedFor = (*(uint32_t *)copyin((uintptr_t)(uint32_t *)nd,

		sizeof (uint32_t))) >= 4096 ? "" :

	    (curpsinfo->pr_dmodel == PR_MODEL_ILP32 ?

		copyinstr(*(uint32_t *)copyin((uintptr_t)

		    &((node_dtrace_http_server_request_v1_t *)nd)->forwardedFor,

		    sizeof (uint32_t))) :

		copyinstr(*(uint64_t *)copyin((uintptr_t)

		    &((node_dtrace_http_server_request64_v1_t *)nd)->

		    forwardedFor, sizeof (uint64_t))));

};

/*

 * Translate from node_dtrace_http_client_request_t (received from node 0.6 and

 * later versions) to node_http_request_t.

 */

translator node_http_request_t <node_dtrace_http_client_request_t *nd> {

	url = (*(uint32_t *)copyin((uintptr_t)(uint32_t *)nd,

		sizeof (uint32_t))) >= 4096 ?

	    (curpsinfo->pr_dmodel == PR_MODEL_ILP32 ?

		copyinstr(*(uint32_t *)copyin((uintptr_t)

		    &((node_dtrace_http_server_request_v0_t *)nd)->url,

		    sizeof (uint32_t))) :

		copyinstr(*(uint64_t *)copyin((uintptr_t)

		    &((node_dtrace_http_server_request64_v0_t *)nd)->url,

		    sizeof (uint64_t)))) :

	    (curpsinfo->pr_dmodel == PR_MODEL_ILP32 ?

		copyinstr(*(uint32_t *)copyin((uintptr_t)

		    &((node_dtrace_http_server_request_v1_t *)nd)->url,

		    sizeof (uint32_t))) :

		copyinstr(*(uint64_t *)copyin((uintptr_t)

		    &((node_dtrace_http_server_request64_v1_t *)nd)->url,

		    sizeof (uint64_t))));

	method = (*(uint32_t *)copyin((uintptr_t)(uint32_t *)nd,

		sizeof (uint32_t))) >= 4096 ?

	    (curpsinfo->pr_dmodel == PR_MODEL_ILP32 ?

		copyinstr(*(uint32_t *)copyin((uintptr_t)

		    &((node_dtrace_http_server_request_v0_t *)nd)->method,

		    sizeof (uint32_t))) :

		copyinstr(*(uint64_t *)copyin((uintptr_t)

		    &((node_dtrace_http_server_request64_v0_t *)nd)->method,

		    sizeof (uint64_t)))) :

	    (curpsinfo->pr_dmodel == PR_MODEL_ILP32 ?

		copyinstr(*(uint32_t *)copyin((uintptr_t)

		    &((node_dtrace_http_server_request_v1_t *)nd)->method,

		    sizeof (uint32_t))) :

		copyinstr(*(uint64_t *)copyin((uintptr_t)

		    &((node_dtrace_http_server_request64_v1_t *)nd)->method,

		    sizeof (uint64_t))));

	forwardedFor = "";

};

/*

 * Translate from node_dtrace_http_request_t (received from versions of node

 * prior to 0.6) to node_http_request_t.  This is used for both the server and

 * client probes since these versions of node didn't distinguish between the

 * types used in these probes.

 */

translator node_http_request_t <node_dtrace_http_request_t *nd> {

	url = (*(uint32_t *)copyin((uintptr_t)(uint32_t *)nd,

		sizeof (uint32_t))) >= 4096 ?

	    (curpsinfo->pr_dmodel == PR_MODEL_ILP32 ?

		copyinstr(*(uint32_t *)copyin((uintptr_t)

		    &((node_dtrace_http_server_request_v0_t *)nd)->url,

		    sizeof (uint32_t))) :

		copyinstr(*(uint64_t *)copyin((uintptr_t)

		    &((node_dtrace_http_server_request64_v0_t *)nd)->url,

		    sizeof (uint64_t)))) :

	    (curpsinfo->pr_dmodel == PR_MODEL_ILP32 ?

		copyinstr(*(uint32_t *)copyin((uintptr_t)

		    &((node_dtrace_http_server_request_v1_t *)nd)->url,

		    sizeof (uint32_t))) :

		copyinstr(*(uint64_t *)copyin((uintptr_t)

		    &((node_dtrace_http_server_request64_v1_t *)nd)->url,

		    sizeof (uint64_t))));

	method = (*(uint32_t *)copyin((uintptr_t)(uint32_t *)nd,

		sizeof (uint32_t))) >= 4096 ?

	    (curpsinfo->pr_dmodel == PR_MODEL_ILP32 ?

		copyinstr(*(uint32_t *)copyin((uintptr_t)

		    &((node_dtrace_http_server_request_v0_t *)nd)->method,

		    sizeof (uint32_t))) :

		copyinstr(*(uint64_t *)copyin((uintptr_t)

		    &((node_dtrace_http_server_request64_v0_t *)nd)->method,

		    sizeof (uint64_t)))) :

	    (curpsinfo->pr_dmodel == PR_MODEL_ILP32 ?

		copyinstr(*(uint32_t *)copyin((uintptr_t)

		    &((node_dtrace_http_server_request_v1_t *)nd)->method,

		    sizeof (uint32_t))) :

		copyinstr(*(uint64_t *)copyin((uintptr_t)

		    &((node_dtrace_http_server_request64_v1_t *)nd)->method,

		    sizeof (uint64_t))));

	forwardedFor = (*(uint32_t *) copyin((uintptr_t)(uint32_t *)nd,

		sizeof (uint32_t))) >= 4096 ? "" :

	    (curpsinfo->pr_dmodel == PR_MODEL_ILP32 ?

		copyinstr(*(uint32_t *)copyin((uintptr_t)

		    &((node_dtrace_http_server_request_v1_t *)nd)->forwardedFor,

		    sizeof (uint32_t))) :

		copyinstr(*(uint64_t *)copyin((uintptr_t)

		    &((node_dtrace_http_server_request64_v1_t *)nd)->

		    forwardedFor, sizeof (uint64_t))));

};