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Created March 14, 2012 22:10
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32-bit specific node.d file (for use in zones)
$ dtrace -q -L /home/dap -n 'node*:::http-server-request {printf("%s %s\n", args[0]->method, args[0]->url)}'
PUT /foo/bar/bob
GET /hiya
^C
/* 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 =
copyinstr((uintptr_t)*(uint32_t *)copyin((uintptr_t)&nc->remote,
sizeof (int32_t)));
bufferSize =
*(uint32_t *)copyin((uintptr_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 ?
copyinstr(*(uint32_t *)copyin((uintptr_t)
&((node_dtrace_http_server_request_v0_t *)nd)->url,
sizeof (uint32_t))) :
copyinstr(*(uint32_t *)copyin((uintptr_t)
&((node_dtrace_http_server_request_v1_t *)nd)->url,
sizeof (uint32_t)));
method = (*(uint32_t *)copyin((uintptr_t)(uint32_t *)nd,
sizeof (uint32_t))) >= 4096 ?
copyinstr(*(uint32_t *)copyin((uintptr_t)
&((node_dtrace_http_server_request_v0_t *)nd)->method,
sizeof (uint32_t))) :
copyinstr(*(uint32_t *)copyin((uintptr_t)
&((node_dtrace_http_server_request_v1_t *)nd)->method,
sizeof (uint32_t)));
forwardedFor = (*(uint32_t *)copyin((uintptr_t)(uint32_t *)nd,
sizeof (uint32_t))) >= 4096 ? "" :
copyinstr(*(uint32_t *)copyin((uintptr_t)
&((node_dtrace_http_server_request_v1_t *)nd)->forwardedFor,
sizeof (uint32_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 ?
copyinstr(*(uint32_t *)copyin((uintptr_t)
&((node_dtrace_http_server_request_v0_t *)nd)->url,
sizeof (uint32_t))) :
copyinstr(*(uint32_t *)copyin((uintptr_t)
&((node_dtrace_http_server_request_v1_t *)nd)->url,
sizeof (uint32_t)));
method = (*(uint32_t *)copyin((uintptr_t)(uint32_t *)nd,
sizeof (uint32_t))) >= 4096 ?
copyinstr(*(uint32_t *)copyin((uintptr_t)
&((node_dtrace_http_server_request_v0_t *)nd)->method,
sizeof (uint32_t))) :
copyinstr(*(uint32_t *)copyin((uintptr_t)
&((node_dtrace_http_server_request_v1_t *)nd)->method,
sizeof (uint32_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 ?
copyinstr(*(uint32_t *)copyin((uintptr_t)
&((node_dtrace_http_server_request_v0_t *)nd)->url,
sizeof (uint32_t))) :
copyinstr(*(uint32_t *)copyin((uintptr_t)
&((node_dtrace_http_server_request_v1_t *)nd)->url,
sizeof (uint32_t)));
method = (*(uint32_t *)copyin((uintptr_t)(uint32_t *)nd,
sizeof (uint32_t))) >= 4096 ?
copyinstr(*(uint32_t *)copyin((uintptr_t)
&((node_dtrace_http_server_request_v0_t *)nd)->method,
sizeof (uint32_t))) :
copyinstr(*(uint32_t *)copyin((uintptr_t)
&((node_dtrace_http_server_request_v1_t *)nd)->method,
sizeof (uint32_t)));
forwardedFor = (*(uint32_t *) copyin((uintptr_t)(uint32_t *)nd,
sizeof (uint32_t))) >= 4096 ? "" :
copyinstr(*(uint32_t *)copyin((uintptr_t)
&((node_dtrace_http_server_request_v1_t *)nd)->forwardedFor,
sizeof (uint32_t)));
};
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