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clixon/apps/backend/backend_plugin.c
Olof hagsand 85af4342dc common plugin code, removed clixon_proc.c
2017-04-12 22:39:01 +02:00

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/*
*
***** BEGIN LICENSE BLOCK *****
Copyright (C) 2009-2017 Olof Hagsand and Benny Holmgren
This file is part of CLIXON.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
Alternatively, the contents of this file may be used under the terms of
the GNU General Public License Version 3 or later (the "GPL"),
in which case the provisions of the GPL are applicable instead
of those above. If you wish to allow use of your version of this file only
under the terms of the GPL, and not to allow others to
use your version of this file under the terms of Apache License version 2,
indicate your decision by deleting the provisions above and replace them with
the notice and other provisions required by the GPL. If you do not delete
the provisions above, a recipient may use your version of this file under
the terms of any one of the Apache License version 2 or the GPL.
***** END LICENSE BLOCK *****
*
*/
#ifdef HAVE_CONFIG_H
#include "clixon_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 <clixon/clixon.h>
#include "clixon_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
backend_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)
* @retval plugin Plugin struct
* @retval NULL Error
*/
static struct plugin *
backend_plugin_load (clicon_handle h,
char *file,
int dlflags)
{
void *handle;
char *name;
struct plugin *new = NULL;
if ((handle = plugin_load(h, file, dlflags)) == NULL)
goto done;
if ((new = malloc(sizeof(*new))) == 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;
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);
done:
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 = realloc(plugins, (nplugins+1) * sizeof (*p))) == NULL) {
clicon_err(OE_UNIX, errno, "realloc");
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
backend_plugin_load_dir(clicon_handle h,
const char *dir)
{
int retval = -1;
int i;
int np = 0;
int ndp;
struct stat st;
char filename[MAXPATHLEN];
struct dirent *dp = NULL;
struct plugin *new;
struct plugin *p = NULL;
char master[MAXPATHLEN];
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;
}
snprintf(master, MAXPATHLEN-1, "%s.so", master_plugin);
/* Allocate plugin group object */
/* Get plugin objects names from plugin directory */
if((ndp = clicon_file_dirent(dir, &dp, "(.so)$", S_IFREG))<0)
goto quit;
/* reset num plugins */
np = 0;
/* Master plugin must be loaded first if it exists. */
snprintf(filename, MAXPATHLEN-1, "%s/%s", dir, master);
if (stat(filename, &st) == 0) {
clicon_debug(1, "Loading master plugin '%.*s' ...",
(int)strlen(filename), filename);
new = backend_plugin_load(h, filename, RTLD_NOW|RTLD_GLOBAL);
if (new == NULL)
goto quit;
if (plugin_append(new) < 0)
goto quit;
}
/* Now load the rest. Note plugins is the global variable */
for (i = 0; i < ndp; i++) {
if (strcmp(dp[i].d_name, master) == 0)
continue; /* Skip master now */
snprintf(filename, MAXPATHLEN-1, "%s/%s", dir, dp[i].d_name);
clicon_debug(1, "Loading plugin '%.*s' ...", (int)strlen(filename), filename);
new = backend_plugin_load(h, filename, RTLD_NOW);
if (new == NULL)
goto quit;
/* Append to 'plugins' */
if (plugin_append(new) < 0)
goto quit;
}
/* All good. */
retval = 0;
quit:
if (retval != 0) {
/* XXX p is always NULL */
if (plugins) {
while (--np >= 0){
if ((p = &plugins[np]) == NULL)
continue;
backend_plugin_unload(h, p);
free(p);
}
free(plugins);
}
}
if (dp)
free(dp);
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 (backend_plugin_load_dir(h, CLIXON_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 (backend_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];
backend_plugin_unload(h, p);
}
if (plugins){
free(plugins);
plugins = NULL;
}
nplugins = 0;
return 0;
}
/*! 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;
}
/*! Revert a commit
* @param[in] h CLICON handle
* @param[in] td Transaction data
* @param[in] nr The plugin where an error occured.
* @retval 0 OK
* @retval -1 Error
* The revert is made in plugin before this one. Eg if error occurred in
* plugin 2, then the revert will be made in plugins 1 and 0.
*/
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_clen = td->td_clen;
tr.td_scvec = td->td_tcvec;
tr.td_tcvec = td->td_scvec;
for (i = nr-1; i>=0; 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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