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https://github.com/schoebel/mars
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proc: new trigger interface
Necessary for kernels >= 5.8.x. It should also work with old kernels.
This commit is contained in:
Thomas Schoebel-Theuer
parent
f92a44ecfa
commit
c3cf062fb6
@ -46,6 +46,8 @@
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#include "../buildtag.h"
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#define USE_NEW_TRIGGER
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const char mars_version_string[] = BUILDTAG " (" BUILDHOST " " BUILDDATE ") "
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#ifndef CONFIG_MARS_DEBUG
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"production"
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@ -176,6 +178,153 @@ void interpret_user_message(char *msg)
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}
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}
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#ifdef USE_NEW_TRIGGER
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static DEFINE_MUTEX(trigger_buf_mutex);
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static char trigger_buffer[PAGE_SIZE];
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/* Compatible to old behaviour.
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* Please use the new "t" codes instead.
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* HOPEFULLY this can vanish some day :(
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*/
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static
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int work_trigger_old(void)
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{
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int code = 0;
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sscanf(trigger_buffer, "%d", &code);
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if (code >= 8) {
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mars_remote_trigger(MARS_TRIGGER_LOCAL | MARS_TRIGGER_FROM_REMOTE | MARS_TRIGGER_TO_REMOTE_ALL | MARS_TRIGGER_FULL);
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} else if (code >= 3) {
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mars_remote_trigger(MARS_TRIGGER_LOCAL | MARS_TRIGGER_FROM_REMOTE | MARS_TRIGGER_TO_REMOTE_ALL);
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} else if (code >= 2) {
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mars_remote_trigger(MARS_TRIGGER_LOCAL | MARS_TRIGGER_TO_REMOTE);
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} else if (code >= 1) {
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mars_remote_trigger(MARS_TRIGGER_LOCAL);
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}
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return 0;
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}
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static
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int work_trigger(void)
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{
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/* Deprecated, to disappear */
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if (trigger_buffer[0] == ' ' ||
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(trigger_buffer[0] >= '0' && trigger_buffer[0] <= '9'))
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return work_trigger_old();
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if (!trigger_buffer[0] || !trigger_buffer[1])
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return -EINVAL;
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interpret_user_message(trigger_buffer);
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return 0;
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}
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static
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int trigger_answer(void)
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{
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char *answer = "MARS module not operational\n";
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char *tmp = NULL;
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if (mars_info) {
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answer = "internal error while determining mars_info\n";
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tmp = mars_info();
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if (tmp)
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answer = tmp;
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}
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strncpy(trigger_buffer, answer, sizeof(trigger_buffer));
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brick_string_free(tmp);
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return 0;
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}
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int mars_dotrigger(struct ctl_table *table, int write,
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void *buffer, size_t *lenp, loff_t *ppos)
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{
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int err;
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mutex_lock(&trigger_buf_mutex);
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if (!write) {
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err = trigger_answer();
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if (err < 0)
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goto done_unlock;
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}
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err = proc_dostring(table, write, buffer, lenp, ppos);
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if (write && err >= 0) {
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int status = work_trigger();
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if (status < 0)
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goto done_unlock;
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}
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done_unlock:
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mutex_unlock(&trigger_buf_mutex);
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return err;
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}
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#define LAMPORT_BUF_LEN 128
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/* NO rw-mutex, to enforce strictness of results.
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* This will deliberately limit the userspace parallelism ;)
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* In short, userspace should not overload a long-distance
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* Distributed System as represented by a Lamport Clock.
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* As explained elsewhere, a Lamport Clock should act as
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* a _singleton_ as seen from a local perspective.
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* Nevertheless, a local nesting hierarchy remains possible
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* for improved performance, but suchalike is deliberately _not_
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* exported to userspace.
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* Hopefully this will protect the kernel from intrusion-like
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* misbehaviour.
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* When necessary, some msleep() limitations may be added in future.
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*/
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static DEFINE_MUTEX(lamport_buf_mutex);
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atomic_t lamport_calls = ATOMIC_INIT(0);
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static char lamport_buffer[LAMPORT_BUF_LEN];
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int proc_dolamport(struct ctl_table *table, int write,
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void *buffer, size_t *lenp, loff_t *ppos)
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{
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struct lamport_time know;
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struct lamport_time lnow;
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int calls;
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int len;
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int err = -EINVAL;
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/* also count any tries or failures */
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calls = atomic_inc_return(&lamport_calls);
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if (write)
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goto out;
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mutex_lock(&lamport_buf_mutex);
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get_lamport(&know, &lnow);
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len = scnprintf(lamport_buffer, LAMPORT_BUF_LEN,
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"CURRENT_TIME=%lld.%09ld\n"
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"lamport_now=%lld.%09ld\n"
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"CALLS=%u",
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(s64)know.tv_sec, know.tv_nsec,
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(s64)lnow.tv_sec, lnow.tv_nsec,
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/* may overflow */
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(unsigned)calls);
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if (unlikely(len <= 0 || len >= LAMPORT_BUF_LEN - 1))
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goto out_unlock;
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err = proc_dostring(table, write, buffer, lenp, ppos);
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out_unlock:
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mutex_unlock(&lamport_buf_mutex);
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out:
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return err;
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}
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EXPORT_SYMBOL_GPL(proc_dolamport);
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#else /* USE_NEW_TRIGGER */
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static
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int trigger_sysctl_handler(
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struct ctl_table *table,
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@ -311,6 +460,8 @@ done:
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return res;
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}
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#endif /* USE_NEW_TRIGGER */
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#ifdef CTL_UNNUMBERED
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#define _CTL_NAME .ctl_name = CTL_UNNUMBERED,
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#define _CTL_STRATEGY(handler) .strategy = &handler,
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@ -419,19 +570,37 @@ struct ctl_table mars_table[] = {
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_CTL_NAME
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.procname = "trigger",
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.mode = 0200,
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#ifdef USE_NEW_TRIGGER
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.data = trigger_buffer,
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.maxlen = sizeof(trigger_buffer),
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.proc_handler = &mars_dotrigger,
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#else
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.proc_handler = &trigger_sysctl_handler,
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#endif
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},
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{
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_CTL_NAME
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.procname = "info",
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.mode = 0400,
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#ifdef USE_NEW_TRIGGER
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.data = trigger_buffer,
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.maxlen = sizeof(trigger_buffer),
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.proc_handler = &mars_dotrigger,
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#else
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.proc_handler = &trigger_sysctl_handler,
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#endif
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},
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{
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_CTL_NAME
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.procname = "lamport_clock",
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.mode = 0400,
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#ifdef USE_NEW_TRIGGER
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.data = lamport_buffer,
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.maxlen = LAMPORT_BUF_LEN,
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.proc_handler = &proc_dolamport,
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#else
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.proc_handler = &lamport_sysctl_handler,
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#endif
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},
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INT_ENTRY("min_update_seconds", mars_min_update, 0600),
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INT_ENTRY("max_lamport_future", max_lamport_future, 0600),
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