mirror of
https://github.com/troglobit/finit.git
synced 2026-10-01 13:33:09 +07:00
Joachim Wiberg
8000d361b3
In 7447192 we dropped support for 'cond set' and 'cond clear' commands
with the motivation they were unsafe and sent the wrong message to the
user. That was true, but mostly because it was too generic and required
the user to call `initctl reload` to apply the changes.
This patch restores the behavior, albeit in a very reduced and simple
format. All conditions set with this command are constrained to the
'usr/...' namespace. No subdirectories are allowed. The argument to
the 'cond set|clear' command is disallowed if it contains '/' or '.'
but anything else is supported, for example:
initctl cond set foo:2
creates a static/oneshot condition in /run/finit/cond/usr/foo:2
These conditions are static and are fully handled by the user. The
initctl command is the recommended, and only supported, way of setting
and clearing usr conditions.
This patch also includes a new plugin, usr.so, which is a very simple
inotify plugin for the /run/finit/cond/usr/ directory. When files are
created or removed here the plugin tells the Finit condition engine to
update and trigger service changes.
For instance, the following service is not started by default at boot:
service <usr/foo> myservice -- MyService
However, as soon as `initctl cond set foo` is called, myservice starts.
Consequently, it is stopped when `initctl cond clr foo` is called.
Another major difference from the original is that this implementation
doesn't send IPC commands to create/delete the conditions. This makes
calling these new commands non-blocking so they can be used very early
in the bootstrap, by plugins, if needed.
Signed-off-by: Joachim Wiberg <troglobit@gmail.com>
134 lines
3.2 KiB
C
134 lines
3.2 KiB
C
/* User-defined condtion event monitor for the Finit condition engine
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*
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* Copyright (c) 2021 Joachim Wiberg <troglobit@gmail.com>
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#include <fnmatch.h>
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#include <glob.h>
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#include <limits.h>
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#include <paths.h>
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#include "finit.h"
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#include "cond.h"
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#include "pid.h"
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#include "plugin.h"
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#include "iwatch.h"
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static struct iwatch iw_usr;
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static void usr_cond(char *name, uint32_t mask)
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{
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char cond[MAX_COND_LEN] = COND_USR;
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strlcat(cond, name, sizeof(cond));
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cond_update(cond);
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}
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static void usr_callback(void *arg, int fd, int events)
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{
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static char ev_buf[8 *(sizeof(struct inotify_event) + NAME_MAX + 1) + 1];
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struct inotify_event *ev;
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ssize_t sz;
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size_t off;
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sz = read(fd, ev_buf, sizeof(ev_buf) - 1);
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if (sz <= 0) {
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_pe("invalid inotify event");
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return;
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}
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ev_buf[sz] = 0;
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for (off = 0; off < (size_t)sz; off += sizeof(*ev) + ev->len) {
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if (off + sizeof(*ev) > (size_t)sz)
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break;
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ev = (struct inotify_event *)&ev_buf[off];
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if (off + sizeof(*ev) + ev->len > (size_t)sz)
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break;
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_d("name %s, event: 0x%08x", ev->name, ev->mask);
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if (!ev->mask)
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continue;
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if (ev->mask & IN_ISDIR)
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continue; /* unsupported */
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if (ev->mask & IN_DELETE)
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sync(); /* dont ask */
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usr_cond(ev->name, ev->mask);
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}
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}
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static void usr_init(void *arg)
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{
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char usrdir[MAX_ARG_LEN];
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char *path;
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if (mkpath(pid_runpath(_PATH_CONDUSR, usrdir, sizeof(usrdir)), 0755) && errno != EEXIST) {
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_pe("Failed creating %s condition directory, %s", COND_USR, _PATH_CONDUSR);
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return;
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}
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path = realpath(_PATH_CONDUSR, NULL);
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if (!path) {
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_pe("Cannot figure out real path to %s, aborting", _PATH_CONDUSR);
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return;
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}
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if (iwatch_add(&iw_usr, path, IN_ONLYDIR))
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iwatch_exit(&iw_usr);
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}
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static plugin_t plugin = {
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.name = __FILE__,
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.hook[HOOK_BASEFS_UP] = { .cb = usr_init },
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};
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PLUGIN_INIT(plugin_init)
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{
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int fd;
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fd = iwatch_init(&iw_usr);
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if (fd < 0)
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return;
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plugin.io.fd = fd;
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plugin.io.cb = usr_callback;
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plugin.io.flags = PLUGIN_IO_READ;
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plugin_register(&plugin);
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}
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PLUGIN_EXIT(plugin_exit)
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{
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iwatch_exit(&iw_usr);
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plugin_unregister(&plugin);
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}
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/**
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* Local Variables:
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* indent-tabs-mode: t
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* c-file-style: "linux"
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* End:
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*/
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