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clixon/apps/backend/backend_plugin.c
Olof hagsand d6e393ea58 Inital commit
2016-02-22 22:17:30 +01:00

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/*
*
Copyright (C) 2009-2016 Olof Hagsand and Benny Holmgren
This file is part of CLICON.
CLICON 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 3 of the License, or
(at your option) any later version.
CLICON 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 CLICON; see the file COPYING. If not, see
<http://www.gnu.org/licenses/>.
*
*/
#ifdef HAVE_CONFIG_H
#include "clicon_config.h" /* generated by config & autoconf */
#endif
#include <stdio.h>
#define __USE_GNU /* strverscmp */
#include <string.h>
#include <stdlib.h>
#include <stdarg.h>
#include <dlfcn.h>
#include <dirent.h>
#include <unistd.h>
#include <errno.h>
#include <signal.h>
#include <syslog.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/param.h>
#include <netinet/in.h>
/* cligen */
#include <cligen/cligen.h>
/* clicon */
#include <clicon/clicon.h>
#include "clicon_backend_transaction.h"
#include "backend_plugin.h"
#include "backend_commit.h"
/*
* Types
*/
/* Following are specific to backend. For common see clicon_plugin.h
* @note the following should match the prototypes in clicon_backend.h
*/
#define PLUGIN_RESET "plugin_reset"
typedef int (plgreset_t)(clicon_handle h, char *dbname); /* Reset system status */
#define PLUGIN_TRANS_BEGIN "transaction_begin"
#define PLUGIN_TRANS_VALIDATE "transaction_validate"
#define PLUGIN_TRANS_COMPLETE "transaction_complete"
#define PLUGIN_TRANS_COMMIT "transaction_commit"
#define PLUGIN_TRANS_END "transaction_end"
#define PLUGIN_TRANS_ABORT "transaction_abort"
typedef int (trans_cb_t)(clicon_handle h, transaction_data td); /* Transaction cbs */
/* Backend (config) plugins */
struct plugin {
char p_name[PATH_MAX]; /* Plugin name */
void *p_handle; /* Dynamic object handle */
plginit_t *p_init; /* Init */
plgstart_t *p_start; /* Start */
plgexit_t *p_exit; /* Exit */
plgreset_t *p_reset; /* Reset state */
trans_cb_t *p_trans_begin; /* Transaction start */
trans_cb_t *p_trans_validate; /* Transaction validation */
trans_cb_t *p_trans_complete; /* Transaction validation complete */
trans_cb_t *p_trans_commit; /* Transaction commit */
trans_cb_t *p_trans_end; /* Transaction completed */
trans_cb_t *p_trans_abort; /* Transaction aborted */
};
/*
* Local variables
*/
static int nplugins = 0;
static struct plugin *plugins = NULL;
/*! Find a plugin by name and return the dlsym handl
* Used by libclicon code to find callback funcctions in plugins.
* @param[in] h Clicon handle
* @param[in] h Name of plugin
* @retval handle Plugin handle if found
* @retval NULL Not found
*/
static void *
config_find_plugin(clicon_handle h,
char *name)
{
int i;
struct plugin *p;
for (i = 0; i < nplugins; i++){
p = &plugins[i];
if (strcmp(p->p_name, name) == 0)
return p->p_handle;
}
return NULL;
}
/*! Initialize plugin code (not the plugins themselves)
* @param[in] h Clicon handle
* @retval 0 OK
* @retval -1 Error
*/
int
config_plugin_init(clicon_handle h)
{
find_plugin_t *fp = config_find_plugin;
clicon_hash_t *data = clicon_data(h);
/* Register CLICON_FIND_PLUGIN in data hash */
if (hash_add(data, "CLICON_FIND_PLUGIN", &fp, sizeof(fp)) == NULL) {
clicon_err(OE_UNIX, errno, "failed to register CLICON_FIND_PLUGIN");
return -1;
}
return 0;
}
/*! Unload a plugin
* @param[in] h Clicon handle
* @param[in] plg Plugin structure
* @retval 0 OK
* @retval -1 Error
*/
static int
plugin_unload(clicon_handle h,
struct plugin *plg)
{
char *error;
/* Call exit function is it exists */
if (plg->p_exit)
plg->p_exit(h);
dlerror(); /* Clear any existing error */
if (dlclose(plg->p_handle) != 0) {
error = (char*)dlerror();
clicon_err(OE_UNIX, 0, "dlclose: %s", error?error:"Unknown error");
return -1;
/* Just report */
}
else
clicon_debug(1, "Plugin '%s' unloaded.", plg->p_name);
return 0;
}
/*! Load a dynamic plugin and call its init-function
* @param[in] h Clicon handle
* @param[in] file The plugin (.so) to load
* @param[in] dlflags Arguments to dlopen(3)
* @param[in] label Chunk label
* @retval plugin Plugin struct
* @retval NULL Error
*/
static struct plugin *
plugin_load (clicon_handle h,
char *file,
int dlflags,
const char *label)
{
char *error;
void *handle;
char *name;
struct plugin *new;
plginit_t *initfun;
dlerror(); /* Clear any existing error */
if ((handle = dlopen (file, dlflags)) == NULL) {
error = (char*)dlerror();
clicon_err(OE_UNIX, 0, "dlopen: %s", error?error:"Unknown error");
return NULL;
}
initfun = dlsym(handle, PLUGIN_INIT);
if ((error = (char*)dlerror()) != NULL) {
clicon_err(OE_UNIX, 0, "dlsym: %s", error);
return NULL;
}
if (initfun(h) != 0) {
dlclose(handle);
if (!clicon_errno) /* sanity: log if clicon_err() is not called ! */
clicon_err(OE_DB, 0, "Unknown error: %s: plugin_init does not make clicon_err call on error",
file);
return NULL;
}
if ((new = chunk(sizeof(*new), label)) == NULL) {
clicon_err(OE_UNIX, errno, "dhunk: %s", strerror(errno));
dlclose(handle);
return NULL;
}
memset(new, 0, sizeof(*new));
name = strrchr(file, '/') ? strrchr(file, '/')+1 : file;
clicon_debug(2, "Loading plugin '%s'.", name);
snprintf(new->p_name, sizeof(new->p_name), "%*s",
(int)strlen(name)-2, name);
new->p_handle = handle;
new->p_init = initfun;
if ((new->p_start = dlsym(handle, PLUGIN_START)) != NULL)
clicon_debug(2, "%s callback registered.", PLUGIN_START);
if ((new->p_exit = dlsym(handle, PLUGIN_EXIT)) != NULL)
clicon_debug(2, "%s callback registered.", PLUGIN_EXIT);
if ((new->p_reset = dlsym(handle, PLUGIN_RESET)) != NULL)
clicon_debug(2, "%s callback registered.", PLUGIN_RESET);
if ((new->p_trans_begin = dlsym(handle, PLUGIN_TRANS_BEGIN)) != NULL)
clicon_debug(2, "%s callback registered.", PLUGIN_TRANS_BEGIN);
if ((new->p_trans_validate = dlsym(handle, PLUGIN_TRANS_VALIDATE)) != NULL)
clicon_debug(2, "%s callback registered.", PLUGIN_TRANS_VALIDATE);
if ((new->p_trans_complete = dlsym(handle, PLUGIN_TRANS_COMPLETE)) != NULL)
clicon_debug(2, "%s callback registered.", PLUGIN_TRANS_COMPLETE);
if ((new->p_trans_commit = dlsym(handle, PLUGIN_TRANS_COMMIT)) != NULL)
clicon_debug(2, "%s callback registered.", PLUGIN_TRANS_COMMIT);
if ((new->p_trans_end = dlsym(handle, PLUGIN_TRANS_END)) != NULL)
clicon_debug(2, "%s callback registered.", PLUGIN_TRANS_END);
if ((new->p_trans_abort = dlsym(handle, PLUGIN_TRANS_ABORT)) != NULL)
clicon_debug(2, "%s callback registered.", PLUGIN_TRANS_ABORT);
clicon_debug(2, "Plugin '%s' loaded.\n", name);
return new;
}
/*! Request plugins to reset system state
* The system 'state' should be the same as the contents of running_db
* @param[in] h Clicon handle
* @param[in] dbname Name of database
* @retval 0 OK
* @retval -1 Error
*/
int
plugin_reset_state(clicon_handle h,
char *dbname)
{
int i;
struct plugin *p;
for (i = 0; i < nplugins; i++) {
p = &plugins[i];
if (p->p_reset) {
clicon_debug(1, "Calling plugin_reset() for %s\n",
p->p_name);
if (((p->p_reset)(h, dbname)) < 0) {
clicon_err(OE_FATAL, 0, "plugin_reset() failed for %s\n",
p->p_name);
return -1;
}
}
}
return 0;
}
/*! Call plugin_start in all plugins
* @param[in] h Clicon handle
* @param[in] argc Command-line arguments
* @param[in] argv Command-line arguments
* @retval 0 OK
* @retval -1 Error
*/
int
plugin_start_hooks(clicon_handle h,
int argc,
char **argv)
{
int i;
struct plugin *p;
for (i = 0; i < nplugins; i++) {
p = &plugins[i];
if (p->p_start) {
optind = 0;
if (((p->p_start)(h, argc, argv)) < 0) {
clicon_err(OE_FATAL, 0, "plugin_start() failed for %s\n",
p->p_name);
return -1;
}
}
}
return 0;
}
/*! Append plugin to list
* @param[in] p Plugin
* @retval 0 OK
* @retval -1 Error
*/
static int
plugin_append(struct plugin *p)
{
struct plugin *new;
if ((new = rechunk(plugins, (nplugins+1) * sizeof (*p), NULL)) == NULL) {
clicon_err(OE_UNIX, errno, "chunk");
return -1;
}
memset (&new[nplugins], 0, sizeof(new[nplugins]));
memcpy (&new[nplugins], p, sizeof(new[nplugins]));
plugins = new;
nplugins++;
return 0;
}
/*! Load backend plugins found in a directory
* The plugins must have the '.so' suffix
* @param[in] h Clicon handle
* @param[in] dir Backend plugin directory
* @retval 0 OK
* @retval -1 Error
*/
static int
config_plugin_load_dir(clicon_handle h,
const char *dir)
{
int retval = -1;
int i;
int np = 0;
int ndp;
struct stat st;
char *filename;
struct dirent *dp;
struct plugin *new;
struct plugin *p = NULL;
char *master;
char *master_plugin;
/* Format master plugin path */
if ((master_plugin = clicon_master_plugin(h)) == NULL){
clicon_err(OE_PLUGIN, 0, "clicon_master_plugin option not set");
goto quit;
}
master = chunk_sprintf(__FUNCTION__, "%s.so", master_plugin);
if (master == NULL) {
clicon_err(OE_PLUGIN, errno, "chunk_sprintf master plugin");
goto quit;
}
/* Allocate plugin group object */
/* Get plugin objects names from plugin directory */
if((ndp = clicon_file_dirent(dir, &dp, "(.so)$", S_IFREG, __FUNCTION__))<0)
goto quit;
/* reset num plugins */
np = 0;
/* Master plugin must be loaded first if it exists. */
filename = chunk_sprintf(__FUNCTION__, "%s/%s", dir, master);
if (filename == NULL) {
clicon_err(OE_UNIX, errno, "chunk");
goto quit;
}
if (stat(filename, &st) == 0) {
clicon_debug(1, "Loading master plugin '%.*s' ...",
(int)strlen(filename), filename);
new = plugin_load(h, filename, RTLD_NOW|RTLD_GLOBAL, __FUNCTION__);
if (new == NULL)
goto quit;
if (plugin_append(new) < 0)
goto quit;
}
/* Now load the rest */
for (i = 0; i < ndp; i++) {
if (strcmp(dp[i].d_name, master) == 0)
continue; /* Skip master now */
filename = chunk_sprintf(__FUNCTION__, "%s/%s", dir, dp[i].d_name);
clicon_debug(1, "Loading plugin '%.*s' ...", (int)strlen(filename), filename);
if (filename == NULL) {
clicon_err(OE_UNIX, errno, "chunk");
goto quit;
}
new = plugin_load (h, filename, RTLD_NOW, __FUNCTION__);
if (new == NULL)
goto quit;
if (plugin_append(new) < 0)
goto quit;
}
/* All good. */
retval = 0;
quit:
if (retval != 0) {
if (p) {
while (--np >= 0)
plugin_unload (h, &p[np]);
unchunk(p);
}
}
unchunk_group(__FUNCTION__);
return retval;
}
/*! Load a plugin group.
* @param[in] h Clicon handle
* @retval 0 OK
* @retval -1 Error
*/
int
plugin_initiate(clicon_handle h)
{
char *dir;
/* First load CLICON system plugins */
if (config_plugin_load_dir(h, CLICON_BACKEND_SYSDIR) < 0)
return -1;
/* Then load application plugins */
if ((dir = clicon_backend_dir(h)) == NULL){
clicon_err(OE_PLUGIN, 0, "backend_dir not defined");
return -1;
}
if (config_plugin_load_dir(h, dir) < 0)
return -1;
return 0;
}
/*! Unload and deallocate all backend plugins
* @param[in] h Clicon handle
* @retval 0 OK
* @retval -1 Error
*/
int
plugin_finish(clicon_handle h)
{
int i;
struct plugin *p;
for (i = 0; i < nplugins; i++) {
p = &plugins[i];
plugin_unload(h, p);
}
if (plugins)
unchunk(plugins);
nplugins = 0;
return 0;
}
/*! Call from frontend to function 'func' in plugin 'plugin'.
* Plugin function is supposed to populate 'retlen' and 'retarg' where
* 'retarg' is malloc:ed data if non-NULL.
* @param[in] h Clicon handle
* @param[in] req Clicon message containing information about the downcall
* @param[out] retlen Length of return value
* @param[out] ret Return value
* @retval 0 OK
* @retval -1 Error
*/
int
plugin_downcall(clicon_handle h,
struct clicon_msg_call_req *req,
uint16_t *retlen,
void **retarg)
{
int retval = -1;
int i;
downcall_cb funcp;
char name[PATH_MAX];
char *error;
struct plugin *p;
for (i = 0; i < nplugins; i++) {
p = &plugins[i];
strncpy(name, p->p_name, sizeof(name)-1);
if (!strcmp(name+strlen(name)-3, ".so"))
name[strlen(name)-3] = '\0';
/* If no plugin is given or the plugin-name matches */
if (req->cr_plugin == NULL || strlen(req->cr_plugin)==0 ||
strcmp(name, req->cr_plugin) == 0) {
funcp = dlsym(p->p_handle, req->cr_func);
if ((error = (char*)dlerror()) != NULL) {
clicon_err(OE_PROTO, ENOENT,
"Function does not exist: %s()", req->cr_func);
return -1;
}
retval = funcp(h, req->cr_op, req->cr_arglen, req->cr_arg, retlen, retarg);
goto done;
}
}
clicon_err(OE_PROTO, ENOENT,"%s: %s(): Plugin does not exist: %s",
__FUNCTION__, req->cr_func, req->cr_plugin);
return -1;
done:
return retval;
}
/*! Create and initialize transaction */
transaction_data_t *
transaction_new(void)
{
transaction_data_t *td;
static uint64_t id = 0; /* Global transaction id */
if ((td = malloc(sizeof(*td))) == NULL){
clicon_err(OE_CFG, errno, "malloc");
return NULL;
}
memset(td, 0, sizeof(*td));
td->td_id = id++;
return td;
}
/*! Free transaction structure */
int
transaction_free(transaction_data_t *td)
{
if (td->td_src)
xml_free(td->td_src);
if (td->td_target)
xml_free(td->td_target);
if (td->td_dvec)
free(td->td_dvec);
if (td->td_avec)
free(td->td_avec);
if (td->td_scvec)
free(td->td_scvec);
if (td->td_tcvec)
free(td->td_tcvec);
free(td);
return 0;
}
/* The plugin_transaction routines need access to struct plugin which is local to this file */
/*! Call transaction_begin() in all plugins before a validate/commit.
* @param[in] h Clicon handle
* @param[in] td Transaction data
* @retval 0 OK
* @retval -1 Error: one of the plugin callbacks returned error
*/
int
plugin_transaction_begin(clicon_handle h,
transaction_data_t *td)
{
int i;
int retval = 0;
struct plugin *p;
for (i = 0; i < nplugins; i++) {
p = &plugins[i];
if (p->p_trans_begin)
if ((retval = (p->p_trans_begin)(h, (transaction_data)td)) < 0){
if (!clicon_errno) /* sanity: log if clicon_err() is not called ! */
clicon_log(LOG_NOTICE, "%s: Plugin '%s' %s callback does not make clicon_err call on error",
__FUNCTION__, p->p_name, PLUGIN_TRANS_BEGIN);
break;
}
}
return retval;
}
/*! Call transaction_validate callbacks in all backend plugins
* @param[in] h Clicon handle
* @param[in] td Transaction data
* @retval 0 OK. Validation succeeded in all plugins
* @retval -1 Error: one of the plugin callbacks returned validation fail
*/
int
plugin_transaction_validate(clicon_handle h,
transaction_data_t *td)
{
int retval = 0;
int i;
struct plugin *p;
for (i = 0; i < nplugins; i++){
p = &plugins[i];
if (p->p_trans_validate)
if ((retval = (p->p_trans_validate)(h, (transaction_data)td)) < 0){
if (!clicon_errno) /* sanity: log if clicon_err() is not called ! */
clicon_log(LOG_NOTICE, "%s: Plugin '%s' %s callback does not make clicon_err call on error",
__FUNCTION__, p->p_name, PLUGIN_TRANS_VALIDATE);
break;
}
}
return retval;
}
/*! Call transaction_complete() in all plugins after validation (before commit)
* @param[in] h Clicon handle
* @param[in] td Transaction data
* @retval 0 OK
* @retval -1 Error: one of the plugin callbacks returned error
* @note Call plugins which have commit dependencies?
* @note Rename to transaction_complete?
*/
int
plugin_transaction_complete(clicon_handle h,
transaction_data_t *td)
{
int i;
int retval = 0;
struct plugin *p;
for (i = 0; i < nplugins; i++){
p = &plugins[i];
if (p->p_trans_complete)
if ((retval = (p->p_trans_complete)(h, (transaction_data)td)) < 0){
if (!clicon_errno) /* sanity: log if clicon_err() is not called ! */
clicon_log(LOG_NOTICE, "%s: Plugin '%s' %s callback does not make clicon_err call on error",
__FUNCTION__, p->p_name, PLUGIN_TRANS_COMPLETE);
break;
}
}
return retval;
}
int
plugin_transaction_revert(clicon_handle h,
transaction_data_t *td,
int nr)
{
int retval = 0;
transaction_data_t tr; /* revert transaction */
int i;
struct plugin *p;
/* Create a new reversed transaction from the original where src and target
are swapped */
memcpy(&tr, td, sizeof(tr));
tr.td_src = td->td_target;
tr.td_target = td->td_src;
tr.td_dlen = td->td_alen;
tr.td_dvec = td->td_avec;
tr.td_alen = td->td_dlen;
tr.td_avec = td->td_dvec;
tr.td_scvec = td->td_tcvec;
tr.td_tcvec = td->td_scvec;
for (i = nr-1; i; i--){
p = &plugins[i];
if (p->p_trans_commit)
if ((p->p_trans_commit)(h, (transaction_data)&tr) < 0){
clicon_log(LOG_NOTICE, "Plugin '%s' %s revert callback failed",
p->p_name, PLUGIN_TRANS_COMMIT);
break;
}
}
return retval; /* ignore errors */
}
/*! Call transaction_commit callbacks in all backend plugins
* @param[in] h Clicon handle
* @param[in] td Transaction data
* @retval 0 OK
* @retval -1 Error: one of the plugin callbacks returned error
* If any of the commit callbacks fail by returning -1, a revert of the
* transaction is tried by calling the commit callbacsk with reverse arguments
* and in reverse order.
*/
int
plugin_transaction_commit(clicon_handle h,
transaction_data_t *td)
{
int retval = 0;
int i;
struct plugin *p;
for (i = 0; i < nplugins; i++){
p = &plugins[i];
if (p->p_trans_commit)
if ((retval = (p->p_trans_commit)(h, (transaction_data)td)) < 0){
if (!clicon_errno) /* sanity: log if clicon_err() is not called ! */
clicon_log(LOG_NOTICE, "%s: Plugin '%s' %s callback does not make clicon_err call on error",
__FUNCTION__, p->p_name, PLUGIN_TRANS_COMMIT);
/* Make an effort to revert transaction */
plugin_transaction_revert(h, td, i);
break;
}
}
return retval;
}
/*! Call transaction_end() in all plugins after a successful commit.
* @param[in] h Clicon handle
* @param[in] td Transaction data
* @retval 0 OK
* @retval -1 Error
*/
int
plugin_transaction_end(clicon_handle h,
transaction_data_t *td)
{
int retval = 0;
int i;
struct plugin *p;
for (i = 0; i < nplugins; i++) {
p = &plugins[i];
if (p->p_trans_end)
if ((retval = (p->p_trans_end)(h, (transaction_data)td)) < 0){
if (!clicon_errno) /* sanity: log if clicon_err() is not called ! */
clicon_log(LOG_NOTICE, "%s: Plugin '%s' %s callback does not make clicon_err call on error",
__FUNCTION__, p->p_name, PLUGIN_TRANS_END);
break;
}
}
return retval;
}
/*! Call transaction_abort() in all plugins after a failed validation/commit.
* @param[in] h Clicon handle
* @param[in] td Transaction data
* @retval 0 OK
* @retval -1 Error
*/
int
plugin_transaction_abort(clicon_handle h,
transaction_data_t *td)
{
int retval = 0;
int i;
struct plugin *p;
for (i = 0; i < nplugins; i++) {
p = &plugins[i];
if (p->p_trans_abort)
(p->p_trans_abort)(h, (transaction_data)td); /* dont abort on error */
}
return retval;
}
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