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wireshark/echld_dispatcher.c

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/* echld_dispatcher.c
* epan working child API internals
* Dispatcher process routines and definitions
*
* $Id$
*
* Wireshark - Network traffic analyzer
* By Gerald Combs <gerald@wireshark.org>
* Copyright 1998 Gerald Combs
*
* Copyright (c) 2013 by Luis Ontanon <luis@ontanon.org>
*
* 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.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include "echld-int.h"
/**
DISPATCHER
**/
struct dispatcher_child {
unsigned chld_id;
child_state_t state;
echld_reader_t reader;
int write_fd;
int pid;
gboolean closing;
};
struct dispatcher {
int parent_out;
echld_reader_t parent_in;
struct dispatcher_child* children;
int max_children;
int nchildren;
int reqh_id;
int pid;
int ppid;
struct _encs {
child_encoder_t* to_parent;
echld_parent_encoder_t* to_child;
} enc;
struct _decs {
child_decoder_t* from_parent;
parent_decoder_t* from_child;
} dec;
gboolean closing;
};
struct dispatcher* dispatcher;
#define DISP_RESP(B,T) (echld_write_frame( dispatcher->parent_out, (B), 0, (T), dispatcher->reqh_id, NULL))
#ifdef DEBUG_DISPATCHER
static int dbg_level = 0;
void dispatcher_debug(int level, char* fmt, ...) {
va_list ap;
char* str;
if (dbg_level<level) return;
va_start(ap, fmt);
str = g_strdup_vprintf(fmt,ap);
va_end(ap);
fprintf(stderr, "dispatcher[%d]: reqh_id=%d dbg_level=%d message='%s'", dispatcher->pid, dispatcher->reqh_id, level, str);
g_free(str);
}
static char* param_get_dbg_level(char** err ) {
return g_strdup_printf("%d",dbg_level);
}
static echld_bool_t param_set_dbg_level(char* val , char** err ) {
char* p;
int lvl = strtol(val, &p, 10);
if (p<=val) {
*err = g_strdup("not an integer");
return FALSE;
} else if (lvl < 0 || lvl > 5) {
*err = g_strdup_printf("invalid level=%d (min=0 max=5)",lvl);
return FALSE;
}
dbg_level = lvl;
return TRUE;
}
#define DISP_DBG(attrs) ( dispatcher_debug attrs )
#else
#define DISP_DBG(attrs)
#endif
/* parameters */
int wait_chldn = 0;
static char* param_get_wait_chldn(char** err ) {
return g_strdup_printf("%d",wait_chldn);
}
static echld_bool_t param_set_wait_chldn(char* val , char** err ) {
char* p;
int lvl = strtol(val, &p, 10);
if (p<=val) {
*err = g_strdup("not an integer");
return FALSE;
} else if (lvl < 0 || lvl > 10) {
*err = g_strdup_printf("invalid level=%d (min=0 max=5)",lvl);
return FALSE;
}
wait_chldn = lvl;
return TRUE;
}
static param_t disp_params[] = {
#ifdef DEBUG_DISPATCHER
{"dbg_level", param_get_dbg_level, param_set_dbg_level},
# endif
{"wait_chldn",param_get_wait_chldn,param_set_wait_chldn},
{NULL,NULL,NULL} };
static param_t* get_paramset(char* name) {
int i;
for (i = 0; disp_params[i].name != NULL;i++) {
if (strcmp(name,disp_params[i].name) == 0 ) return &(disp_params[i]);
}
return NULL;
}
void dispatcher_err(int err, const char* fmt, ...) {
size_t len= 1024;
guint8* b[len];
char err_str[len];
GByteArray* em;
va_list ap;
va_start(ap, fmt);
g_vsnprintf(err_str,len,fmt,ap);
va_end(ap);
fprintf(stderr, "%s[%d]: error=%d '%s'\n", "dispatcher", dispatcher->pid, err, err_str);
em = (void*)dispatcher->enc.to_parent->error(err, err_str);
echld_write_frame(dispatcher->parent_out, em, 0, ECHLD_ERROR, dispatcher->reqh_id, NULL);
g_ptr_array_free((void*)em,TRUE);
}
static struct dispatcher_child* dispatcher_get_child(struct dispatcher* d, guint16 chld_id) {
int i;
struct dispatcher_child* cc = d->children;
int max_children = d->max_children;
for(i = 0; i < max_children; i++) {
struct dispatcher_child* c = &(c[i]);
if (c->chld_id == chld_id) return c;
}
return NULL;
}
static void dispatcher_clear_child(struct dispatcher_child* c) {
echld_reset_reader(&(c->reader), -1, 4096);
c->chld_id = 0;
c->write_fd = 0;
c->pid = 0;
c->closing = 0;
}
static void preinit_epan() {
/* Here we do initialization of parts of epan that will be the same for every child we fork */
}
static void dispatcher_clear() {
/* remove unnecessary stuff for the working child */
}
void dispatcher_reaper(int sig) {
int status;
int i;
struct dispatcher_child* cc = dispatcher->children;
int max_children = dispatcher->max_children;
int pid = waitpid(-1, &status, WNOHANG);
size_t len= 1024;
guint8* b[len];
GByteArray* em;
for(i = 0; i < max_children; i++) {
struct dispatcher_child* c = &(cc[i]);
if ( c->pid == pid ) {
if (c->closing || dispatcher->closing) {
em = (void*)dispatcher->enc.to_parent->child_dead("OK");
} else {
/* here we do collect crash data !!! */
em = (void*)dispatcher->enc.to_parent->child_dead("Unexpected, probably crashed");
dispatcher_err(ECHLD_ERR_CRASHED_CHILD, "Unexpected dead: pid=%d chld_id=%d", pid, c->chld_id);
}
echld_write_frame(dispatcher->parent_out, em, c->chld_id, ECHLD_CHILD_DEAD, 0, NULL);
dispatcher_clear_child(c);
g_byte_array_free(em,TRUE);
return;
}
}
dispatcher_err(ECHLD_ERR_UNKNOWN_PID, "Unkown child pid: %d", pid);
}
static void dispatcher_destroy() {
int i;
int max_children = dispatcher->max_children;
struct dispatcher_child* cc = dispatcher->children;
/* destroy the dispatcher stuff at closing */
dispatcher->closing = TRUE;
/* kill all alive children */
for(i = 0; i < max_children; i++) {
struct dispatcher_child* c = &(cc[i]);
if ( c->chld_id ) {
kill(c->pid,SIGTERM);
DISP_DBG((1,"Killing chld_id=%d pid=%d"));
continue;
}
}
exit(6666);
}
/* stuff coming from child going to parent */
static int dispatch_to_parent(guint8* b, size_t len, echld_chld_id_t chld_id, echld_msg_type_t type, echld_reqh_id_t reqh_id, void* data) {
struct dispatcher_child* c = data;
dispatcher->reqh_id = reqh_id;
/* TODO: timeouts, clear them */
/* TODO: keep stats */
GByteArray in_ba;
in_ba.data = b;
in_ba.len = len;
if (chld_id != c->chld_id) {
goto misbehabing;
}
switch(type) {
case ECHLD_ERROR: break;
case ECHLD_TIMED_OUT: break;
case ECHLD_HELLO: c->state = IDLE; break;
case ECHLD_CLOSING: c->closing = TRUE; c->state = CLOSED; break;
case ECHLD_PARAM: break;
case ECHLD_PONG: break;
case ECHLD_FILE_INFO: break; // file_info(pre_encoded)
case ECHLD_FILTER_CKD: break; // filter_ckd(ok,df)
case ECHLD_FILE_OPENED: c->state = READING; break;
case ECHLD_INTERFACE_INFO: break; // intf_info(pre-encoded)
case ECHLD_INTERFACE_OPENED: c->state = READY; break;
case ECHLD_CAPTURE_STARTED: c->state = CAPTURING; break;
case ECHLD_NOTIFY: break; // notify(pre-encoded)
case ECHLD_PACKET_SUM: break; // packet_sum(pre-encoded)
case ECHLD_TREE: break; //tree(framenum, tree(pre-encoded) )
case ECHLD_BUFFER: break; // buffer (name,range,totlen,data)
case ECHLD_EOF: c->state = DONE; break;
case ECHLD_CAPTURE_STOPPED: c->state = DONE; break;
case ECHLD_NOTE_ADDED: break;
case ECHLD_PACKET_LIST: break; // packet_list(name,filter,range);
case ECHLD_FILE_SAVED: break;
default:
goto misbehabing;
}
return echld_write_frame(dispatcher->parent_out, &in_ba, chld_id, type, reqh_id, NULL);
misbehabing:
c->state = ERRORED;
c->closing = TRUE;
kill(c->pid,SIGTERM);
dispatcher_err(ECHLD_ERR_CRASHED_CHILD,"chld_id=%d",chld_id);
return 0;
}
void dispatch_new_child(struct dispatcher* dd) {
struct dispatcher_child* c = dispatcher_get_child(dd, 0);
int reqh_id = dd->reqh_id;
int pid;
if ( c ) {
int parent_pipe_fds[2];
int child_pipe_fds[2];
int pipe_to_parent;
int pipe_from_parent;
int pipe_to_child;
int pipe_from_child;
if( pipe(parent_pipe_fds) < 0) {
dispatcher_err(ECHLD_ERR_CANNOT_FORK,"CANNOT OPEN PARENT PIPE: %s",strerror(errno));
return;
}
pipe_from_parent = parent_pipe_fds[0];
pipe_to_child = parent_pipe_fds[1];
if( pipe(child_pipe_fds) < 0) {
close(pipe_from_parent);
close(pipe_to_child);
dispatcher_err(ECHLD_ERR_CANNOT_FORK,"CANNOT OPEN CHILD PIPE: %s",strerror(errno));
return;
}
pipe_from_child = child_pipe_fds[0];
pipe_to_parent = child_pipe_fds[1];
switch (( pid = fork() )) {
case -1: {
close(pipe_to_child);
close(pipe_to_parent);
close(pipe_from_child);
close(pipe_from_parent);
dispatcher_err(ECHLD_ERR_CANNOT_FORK,"CANNOT FORK: %s",strerror(errno));
return;
}
case 0: { /* I'm the child */
int i;
int fdt_len = getdtablesize();
dispatcher_clear(dd);
for(i=0;i<fdt_len;i++) {
if ( i != pipe_from_parent
&& i != pipe_to_parent
&& i != STDERR_FILENO ) {
close(i);
}
}
echld_child_initialize(pipe_from_parent,pipe_to_parent,reqh_id);
exit( echld_child_loop() );
/* it won't */
return;
}
default: {
/* I'm the parent */
guint8 buf[4];
GByteArray out_ba;
out_ba.data = buf;
out_ba.len = 0;
close(pipe_to_parent);
close(pipe_from_parent);
echld_reset_reader(&(c->reader), pipe_from_child,4096);
c->write_fd = pipe_to_child;
c->pid = pid;
dispatcher->nchildren++;
/* configure child */
echld_write_frame(pipe_to_child, &out_ba, c->chld_id, ECHLD_NEW_CHILD, dispatcher->reqh_id, NULL);
return;
}
}
} else {
dispatcher_err(ECHLD_ERR_CANNOT_FORK, "MAX CHILDREN REACHED: max_children=%d",dispatcher->max_children);
return;
}
}
/* process signals sent from parent */
static int dispatch_to_child(guint8* b, size_t len, echld_chld_id_t chld_id, echld_msg_type_t type, echld_reqh_id_t reqh_id, void* data) {
struct dispatcher* disp = data;
disp->reqh_id = reqh_id;
GByteArray in_ba;
in_ba.data = b;
in_ba.len = len;
if (chld_id == 0) { /* these are messages to the dispatcher itself */
switch(type) {
case ECHLD_CLOSE_CHILD:
dispatcher_destroy();
return 0;
case ECHLD_PING:
echld_write_frame(disp->parent_out, &in_ba, chld_id, ECHLD_PONG, reqh_id, NULL);
return 0;
case ECHLD_NEW_CHILD:
dispatch_new_child(disp);
return 0;
case ECHLD_SET_PARAM:{
char* param;
char* value;
if ( disp->dec.from_parent->set_param(b,len,&param,&value) ) {
GByteArray* ba;
param_t* p = get_paramset(param);
char* err;
if (!p) {
dispatcher_err(ECHLD_CANNOT_SET_PARAM,"no such param='%s'",param);
return 0;
}
if (! p->set ) {
dispatcher_err(ECHLD_CANNOT_SET_PARAM,"reason='read only'");
return 0;
}
if (! p->set(value,&err) ) {
dispatcher_err(ECHLD_CANNOT_SET_PARAM,"reason='%s'",err);
g_free(err);
return 0;
}
ba = (void*)disp->enc.to_parent->param(param,value);
DISP_RESP(ba,ECHLD_PARAM);
g_byte_array_free(ba,TRUE);
DISP_DBG((1,"Set Param: param='%s' value='%s'",param,value));
return 0;
} else {
dispatcher_err(ECHLD_CANNOT_SET_PARAM,"reason='decoder error'");
return 0;
}
}
case ECHLD_GET_PARAM: {
GByteArray* ba;
char* param;
if ( disp->dec.from_parent->get_param(b,len,&param) ) {
char* err;
char* val;
param_t* p = get_paramset(param);
if (!p) {
dispatcher_err(ECHLD_CANNOT_GET_PARAM,"no such param='%s'",param);
return 0;
}
if (! p->get ) {
dispatcher_err(ECHLD_CANNOT_SET_PARAM,"reason='write only'");
return 0;
}
if (!(val = p->get(&err))) {
dispatcher_err(ECHLD_CANNOT_GET_PARAM,"reason='%s'",err);
g_free(err);
return 0;
}
ba = (void*)disp->enc.to_parent->param(param,val);
DISP_RESP(ba,ECHLD_PARAM);
g_byte_array_free(ba,TRUE);
DISP_DBG((2,"Get Param: param='%s' value='%s'",param,val));
return 0;
} else {
dispatcher_err(ECHLD_CANNOT_GET_PARAM,"reason='decoder error'");
return 0;
}
}
default:
dispatcher_err(ECHLD_ERR_WRONG_MSG, "wrong message to dispatcher type='%c'", type);
return 0;
}
} else {
struct dispatcher_child* c;
if (! (c = dispatcher_get_child(dispatcher, chld_id)) ) {
dispatcher_err(ECHLD_ERR_NO_SUCH_CHILD, "wrong chld_id %d", chld_id);
return 0;
}
switch(type) {
case ECHLD_CLOSE_CHILD:
c->closing = TRUE;
c->state = CLOSED;
goto relay_frame;
case ECHLD_OPEN_FILE:
c->state = READING;
goto relay_frame;
case ECHLD_OPEN_INTERFACE:
c->state = READY;
goto relay_frame;
case ECHLD_START_CAPTURE:
c->state = CAPTURING;
goto relay_frame;
case ECHLD_STOP_CAPTURE:
c->state = DONE;
goto relay_frame;
case ECHLD_SAVE_FILE:
case ECHLD_APPLY_FILTER:
case ECHLD_SET_PARAM:
case ECHLD_GET_PARAM:
case ECHLD_PING:
case ECHLD_LIST_FILES:
case ECHLD_CHK_FILTER:
case ECHLD_LIST_INTERFACES:
case ECHLD_GET_SUM:
case ECHLD_GET_TREE:
case ECHLD_GET_BUFFER:
case ECHLD_ADD_NOTE:
relay_frame:
return echld_write_frame(c->write_fd, &in_ba, chld_id, type, reqh_id, NULL);
default:
dispatcher_err(ECHLD_ERR_WRONG_MSG, "wrong message %d %c", reqh_id, type);
return 0;
}
}
}
int dispatcher_loop() {
int parent_out = dispatcher->parent_out;
int parent_in = dispatcher->parent_in.fd;
struct dispatcher_child* children = dispatcher->children;
do {
fd_set rfds;
fd_set efds;
struct timeval timeout;
struct dispatcher_child* c;
int nfds;
FD_ZERO(&rfds);
FD_ZERO(&efds);
FD_SET(parent_in,&rfds);
FD_SET(parent_in,&efds);
FD_SET(parent_out,&efds);
for (c = children, nfds = 0; c->pid; c++) {
if (c->chld_id) {
FD_SET(c->reader.fd, &rfds);
FD_SET(c->reader.fd, &efds);
}
nfds++;
}
nfds = select(nfds, &rfds, NULL, &efds, &timeout);
if ( FD_ISSET(parent_in, &efds) || FD_ISSET(parent_out, &efds) ) {
/* XXX deep shit */
break;
}
if (FD_ISSET(parent_in, &rfds)) {
int st = echld_read_frame(&(dispatcher->parent_in), dispatch_to_child, dispatcher);
if (st < 0) {
/* XXX */
continue;
}
}
for (c=children; c->pid; c++) {
if (c->chld_id) {
if ( FD_ISSET(c->reader.fd,&efds) ) {
/* XXX cleanup child and report */
continue;
}
if (FD_ISSET(c->reader.fd,&rfds)) {
int st = echld_read_frame(&(c->reader), dispatch_to_parent, c);
if (st < 0) {
/* XXX cleanup child and report */
continue;
}
continue;
}
}
}
} while(1);
/* won't */
return 1;
}
void echld_dispatcher_start(int* in_pipe_fds, int* out_pipe_fds) {
static struct dispatcher d;
int fdt_len = getdtablesize();
int i;
preinit_epan();
signal(SIGCHLD,dispatcher_reaper);
dispatcher = &d;
echld_init_reader(&(d.parent_in),in_pipe_fds[0],4096);
d.parent_out = out_pipe_fds[1];
d.children = g_malloc0(ECHLD_MAX_CHILDREN * sizeof(struct dispatcher_child));
d.max_children = ECHLD_MAX_CHILDREN;
d.nchildren = 0;
d.reqh_id = -1;
d.pid = getpid();
echld_get_all_codecs(&(d.enc.to_parent), &(d.dec.from_parent), &(d.enc.to_child), &(d.dec.from_child));
dispatcher_clear();
/* close all fds but those used */
for(i=0;i<fdt_len;i++) {
if ( i != d.parent_in.fd
&& i != d.parent_out
&& i != STDERR_FILENO ) {
close(i);
}
}
exit(dispatcher_loop());
}
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