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/*
* rc-plugin.c
* Simple plugin handler
*/
/*
* Copyright (c) 2007-2015 The OpenRC Authors.
* See the Authors file at the top-level directory of this distribution and
* https://github.com/OpenRC/openrc/blob/master/AUTHORS
*
* This file is part of OpenRC. It is subject to the license terms in
* the LICENSE file found in the top-level directory of this
* distribution and at https://github.com/OpenRC/openrc/blob/master/LICENSE
* This file may not be copied, modified, propagated, or distributed
* except according to the terms contained in the LICENSE file.
*/
#include <sys/types.h>
#include <sys/wait.h>
#include <dirent.h>
#include <dlfcn.h>
#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "einfo.h"
#include "queue.h"
#include "rc.h"
#include "rc-misc.h"
#include "rc-plugin.h"
#define RC_PLUGIN_HOOK "rc_plugin_hook"
bool rc_in_plugin = false;
typedef struct plugin
{
char *name;
void *handle;
int (*hook)(RC_HOOK, const char *);
TAILQ_ENTRY(plugin) entries;
} PLUGIN;
TAILQ_HEAD(, plugin) plugins;
#ifndef __FreeBSD__
dlfunc_t
dlfunc(void * __restrict handle, const char * __restrict symbol)
{
union {
void *d;
dlfunc_t f;
} rv;
rv.d = dlsym(handle, symbol);
return rv.f;
}
#endif
void
rc_plugin_load(void)
{
DIR *dp;
struct dirent *d;
PLUGIN *plugin;
char *file = NULL;
void *h;
int (*fptr)(RC_HOOK, const char *);
/* Don't load plugins if we're in one */
if (rc_in_plugin)
return;
TAILQ_INIT(&plugins);
if (!(dp = opendir(RC_PLUGINDIR)))
return;
while ((d = readdir(dp))) {
if (d->d_name[0] == '.')
continue;
xasprintf(&file, RC_PLUGINDIR "/%s", d->d_name);
h = dlopen(file, RTLD_LAZY);
free(file);
if (h == NULL) {
eerror("dlopen: %s", dlerror());
continue;
}
fptr = (int (*)(RC_HOOK, const char *))
dlfunc(h, RC_PLUGIN_HOOK);
if (fptr == NULL) {
eerror("%s: cannot find symbol `%s'",
d->d_name, RC_PLUGIN_HOOK);
dlclose(h);
} else {
plugin = xmalloc(sizeof(*plugin));
plugin->name = xstrdup(d->d_name);
plugin->handle = h;
plugin->hook = fptr;
TAILQ_INSERT_TAIL(&plugins, plugin, entries);
}
}
closedir(dp);
}
int
rc_waitpid(pid_t pid)
{
int status;
while (waitpid(pid, &status, 0) == -1) {
if (errno != EINTR) {
status = -1;
break;
}
}
return status;
}
void
rc_plugin_run(RC_HOOK hook, const char *value)
{
PLUGIN *plugin;
struct sigaction sa;
sigset_t empty;
sigset_t full;
sigset_t old;
int i;
int flags;
int pfd[2];
pid_t pid;
char *buffer;
char *token;
char *p;
ssize_t nr;
int retval;
/* Don't run plugins if we're in one */
if (rc_in_plugin)
return;
/* We need to block signals until we have forked */
memset(&sa, 0, sizeof(sa));
sa.sa_handler = SIG_DFL;
sigemptyset(&sa.sa_mask);
sigemptyset(&empty);
sigfillset(&full);
TAILQ_FOREACH(plugin, &plugins, entries) {
/* We create a pipe so that plugins can affect our environment
* vars, which in turn influence our scripts. */
if (pipe(pfd) == -1) {
eerror("pipe: %s", strerror(errno));
return;
}
/* Stop any scripts from inheriting us.
* This is actually quite important as without this, the splash
* plugin will probably hang when running in silent mode. */
for (i = 0; i < 2; i++)
if ((flags = fcntl (pfd[i], F_GETFD, 0)) < 0 ||
fcntl (pfd[i], F_SETFD, flags | FD_CLOEXEC) < 0)
eerror("fcntl: %s", strerror(errno));
sigprocmask(SIG_SETMASK, &full, &old);
/* We run the plugin in a new process so we never crash
* or otherwise affected by it */
if ((pid = fork()) == -1) {
eerror("fork: %s", strerror(errno));
break;
}
if (pid == 0) {
/* Restore default handlers */
sigaction(SIGCHLD, &sa, NULL);
sigaction(SIGHUP, &sa, NULL);
sigaction(SIGINT, &sa, NULL);
sigaction(SIGQUIT, &sa, NULL);
sigaction(SIGTERM, &sa, NULL);
sigaction(SIGUSR1, &sa, NULL);
sigaction(SIGWINCH, &sa, NULL);
sigprocmask(SIG_SETMASK, &old, NULL);
rc_in_plugin = true;
close(pfd[0]);
rc_environ_fd = fdopen(pfd[1], "w");
retval = plugin->hook(hook, value);
fclose(rc_environ_fd);
rc_environ_fd = NULL;
/* Just in case the plugin sets this to false */
rc_in_plugin = true;
exit(retval);
}
sigprocmask(SIG_SETMASK, &old, NULL);
close(pfd[1]);
buffer = xmalloc(sizeof(char) * BUFSIZ);
memset(buffer, 0, BUFSIZ);
while ((nr = read(pfd[0], buffer, BUFSIZ)) > 0) {
p = buffer;
while (*p && p - buffer < nr) {
token = strsep(&p, "=");
if (token) {
unsetenv(token);
if (*p) {
setenv(token, p, 1);
p += strlen(p) + 1;
} else
p++;
}
}
}
free(buffer);
close(pfd[0]);
rc_waitpid(pid);
}
}
void
rc_plugin_unload(void)
{
PLUGIN *plugin = TAILQ_FIRST(&plugins);
PLUGIN *next;
while (plugin) {
next = TAILQ_NEXT(plugin, entries);
dlclose(plugin->handle);
free(plugin->name);
free(plugin);
plugin = next;
}
TAILQ_INIT(&plugins);
}
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