BadVPN – Rev 1
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/**
* @file daemon.c
* @author Ambroz Bizjak <ambrop7@gmail.com>
*
* @section LICENSE
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the author nor the
* names of its contributors may be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* @section DESCRIPTION
*
* Runs a program in the background, restarting it if it crashes.
* On deinitialization, sends SIGTERM to the daemon and waits for it to terminate
* (unless it's crashed at the time).
*
* Synopsis:
* daemon(list(string) cmd [, map options])
*
* Arguments:
* cmd - Command for the daemon. The first element is the full path
* to the executable, other elements are command line arguments (excluding
* the zeroth argument).
* options - Map of options:
* "keep_stdout":"true" - Start the program with the same stdout as the NCD process.
* "keep_stderr":"true" - Start the program with the same stderr as the NCD process.
* "do_setsid":"true" - Call setsid() in the child before exec. This is needed to
* start the 'agetty' program.
* "username":username_string - Start the process under the permissions of the
* specified user.
* "retry_time":milliseconds - Wait for this long after the daemon exits
* unexpectedtly before starting it again.
*/
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <misc/cmdline.h>
#include <misc/strdup.h>
#include <system/BProcess.h>
#include <ncd/extra/NCDBProcessOpts.h>
#include <ncd/module_common.h>
#include <generated/blog_channel_ncd_daemon.h>
#define DEFAULT_RETRY_TIME 10000
#define STATE_RETRYING 1
#define STATE_RUNNING 2
#define STATE_RUNNING_DIE 3
struct instance {
NCDModuleInst *i;
NCDValRef cmd_arg;
btime_t retry_time;
NCDBProcessOpts opts;
BTimer timer;
BProcess process;
int state;
};
static int build_cmdline (NCDModuleInst *i, NCDValRef cmd_arg, char **exec, CmdLine *cl);
static void start_process (struct instance *o);
static void timer_handler (struct instance *o);
static void process_handler (struct instance *o, int normally, uint8_t normally_exit_status);
static void instance_free (struct instance *o);
static int build_cmdline (NCDModuleInst *i, NCDValRef cmd_arg, char **exec, CmdLine *cl)
{
ASSERT(!NCDVal_IsInvalid(cmd_arg))
if (!NCDVal_IsList(cmd_arg)) {
ModuleLog(i, BLOG_ERROR, "wrong type");
goto fail0;
}
size_t count = NCDVal_ListCount(cmd_arg);
// read exec
if (count == 0) {
ModuleLog(i, BLOG_ERROR, "missing executable name");
goto fail0;
}
NCDValRef exec_arg = NCDVal_ListGet(cmd_arg, 0);
if (!NCDVal_IsStringNoNulls(exec_arg)) {
ModuleLog(i, BLOG_ERROR, "wrong type");
goto fail0;
}
if (!(*exec = ncd_strdup(exec_arg))) {
ModuleLog(i, BLOG_ERROR, "ncd_strdup failed");
goto fail0;
}
// start cmdline
if (!CmdLine_Init(cl)) {
ModuleLog(i, BLOG_ERROR, "CmdLine_Init failed");
goto fail1;
}
// add header
if (!CmdLine_Append(cl, *exec)) {
ModuleLog(i, BLOG_ERROR, "CmdLine_Append failed");
goto fail2;
}
// add additional arguments
for (size_t j = 1; j < count; j++) {
NCDValRef arg = NCDVal_ListGet(cmd_arg, j);
if (!NCDVal_IsStringNoNulls(arg)) {
ModuleLog(i, BLOG_ERROR, "wrong type");
goto fail2;
}
if (!CmdLine_AppendNoNullMr(cl, NCDVal_StringMemRef(arg))) {
ModuleLog(i, BLOG_ERROR, "CmdLine_AppendNoNullMr failed");
goto fail2;
}
}
// finish
if (!CmdLine_Finish(cl)) {
ModuleLog(i, BLOG_ERROR, "CmdLine_Finish failed");
goto fail2;
}
return 1;
fail2:
CmdLine_Free(cl);
fail1:
free(*exec);
fail0:
return 0;
}
static void start_process (struct instance *o)
{
// build cmdline
char *exec;
CmdLine cl;
if (!build_cmdline(o->i, o->cmd_arg, &exec, &cl)) {
goto fail;
}
// start process
struct BProcess_params p_params = NCDBProcessOpts_GetParams(&o->opts);
int res = BProcess_Init2(&o->process, o->i->params->iparams->manager, (BProcess_handler)process_handler, o, exec, CmdLine_Get(&cl), p_params);
CmdLine_Free(&cl);
free(exec);
if (!res) {
ModuleLog(o->i, BLOG_ERROR, "BProcess_Init2 failed");
goto fail;
}
// set state running
o->state = STATE_RUNNING;
return;
fail:
// start timer
BReactor_SetTimer(o->i->params->iparams->reactor, &o->timer);
// set state retrying
o->state = STATE_RETRYING;
}
static void timer_handler (struct instance *o)
{
ASSERT(o->state == STATE_RETRYING)
ModuleLog(o->i, BLOG_INFO, "restarting after crash");
start_process(o);
}
static void process_handler (struct instance *o, int normally, uint8_t normally_exit_status)
{
ASSERT(o->state == STATE_RUNNING || o->state == STATE_RUNNING_DIE)
// free process
BProcess_Free(&o->process);
// if we were requested to die, die now
if (o->state == STATE_RUNNING_DIE) {
instance_free(o);
return;
}
ModuleLog(o->i, BLOG_ERROR, "daemon crashed");
// start timer
BReactor_SetTimer(o->i->params->iparams->reactor, &o->timer);
// set state retrying
o->state = STATE_RETRYING;
}
static int opts_func_unknown (void *user, NCDValRef key, NCDValRef val)
{
struct instance *o = user;
if (NCDVal_IsString(key) && NCDVal_StringEquals(key, "retry_time")) {
if (!ncd_read_time(val, &o->retry_time)) {
ModuleLog(o->i, BLOG_ERROR, "retry_time: bad value");
return 0;
}
return 1;
}
return 0;
}
static void func_new (void *vo, NCDModuleInst *i, const struct NCDModuleInst_new_params *params)
{
struct instance *o = vo;
o->i = i;
// read arguments
NCDValRef opts_arg = NCDVal_NewInvalid();
if (!NCDVal_ListRead(params->args, 1, &o->cmd_arg) &&
!NCDVal_ListRead(params->args, 2, &o->cmd_arg, &opts_arg)
) {
ModuleLog(i, BLOG_ERROR, "wrong arity");
goto fail0;
}
// init options
o->retry_time = DEFAULT_RETRY_TIME;
if (!NCDBProcessOpts_Init(&o->opts, opts_arg, opts_func_unknown, o, i, BLOG_CURRENT_CHANNEL)) {
goto fail0;
}
// init timer
BTimer_Init(&o->timer, o->retry_time, (BTimer_handler)timer_handler, o);
// signal up
NCDModuleInst_Backend_Up(i);
// try starting process
start_process(o);
return;
fail0:
NCDModuleInst_Backend_DeadError(i);
}
static void instance_free (struct instance *o)
{
// free timer
BReactor_RemoveTimer(o->i->params->iparams->reactor, &o->timer);
// free options
NCDBProcessOpts_Free(&o->opts);
NCDModuleInst_Backend_Dead(o->i);
}
static void func_die (void *vo)
{
struct instance *o = vo;
ASSERT(o->state != STATE_RUNNING_DIE)
// if not running, die immediately
if (o->state == STATE_RETRYING) {
instance_free(o);
return;
}
// request termination
BProcess_Terminate(&o->process);
// set state running die
o->state = STATE_RUNNING_DIE;
}
static struct NCDModule modules[] = {
{
.type = "daemon",
.func_new2 = func_new,
.func_die = func_die,
.alloc_size = sizeof(struct instance)
}, {
.type = NULL
}
};
const struct NCDModuleGroup ncdmodule_daemon = {
.modules = modules
};