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/* $OpenBSD: file.c,v 1.22 2016/06/30 21:37:29 ratchov Exp $ */ |
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/* |
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* Copyright (c) 2008-2012 Alexandre Ratchov <alex@caoua.org> |
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* |
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* Permission to use, copy, modify, and distribute this software for any |
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* purpose with or without fee is hereby granted, provided that the above |
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* copyright notice and this permission notice appear in all copies. |
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* |
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES |
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF |
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR |
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES |
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN |
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF |
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. |
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*/ |
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/* |
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* non-blocking file i/o module: each file can be read or written (or |
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* both). To achieve non-blocking io, we simply use the poll() syscall |
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* in an event loop and dispatch events to sub-modules. |
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* |
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* the module also provides trivial timeout implementation, |
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* derived from: |
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* |
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* anoncvs@moule.caoua.org:/midish |
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* |
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* midish/timo.c rev 1.18 |
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* midish/mdep.c rev 1.71 |
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* |
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* A timeout is used to schedule the call of a routine (the callback) |
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* there is a global list of timeouts that is processed inside the |
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* event loop. Timeouts work as follows: |
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* |
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* first the timo structure must be initialized with timo_set() |
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* |
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* then the timeout is scheduled (only once) with timo_add() |
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* |
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* if the timeout expires, the call-back is called; then it can |
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* be scheduled again if needed. It's OK to reschedule it again |
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* from the callback |
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* |
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* the timeout can be aborted with timo_del(), it is OK to try to |
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* abort a timout that has expired |
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* |
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*/ |
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#include <sys/types.h> |
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#include <errno.h> |
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#include <fcntl.h> |
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#include <poll.h> |
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#include <signal.h> |
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#include <stdio.h> |
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#include <stdlib.h> |
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#include <time.h> |
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#include "file.h" |
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#include "utils.h" |
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#define MAXFDS 100 |
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#define TIMER_MSEC 5 |
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void timo_update(unsigned int); |
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void timo_init(void); |
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void timo_done(void); |
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void file_process(struct file *, struct pollfd *); |
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struct timespec file_ts; |
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struct file *file_list; |
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struct timo *timo_queue; |
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unsigned int timo_abstime; |
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int file_slowaccept = 0, file_nfds; |
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#ifdef DEBUG |
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long long file_wtime, file_utime; |
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#endif |
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/* |
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* initialise a timeout structure, arguments are callback and argument |
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* that will be passed to the callback |
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*/ |
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void |
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timo_set(struct timo *o, void (*cb)(void *), void *arg) |
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{ |
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o->cb = cb; |
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o->arg = arg; |
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o->set = 0; |
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} |
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/* |
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* schedule the callback in 'delta' 24-th of microseconds. The timeout |
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* must not be already scheduled |
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*/ |
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void |
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timo_add(struct timo *o, unsigned int delta) |
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{ |
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struct timo **i; |
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unsigned int val; |
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int diff; |
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#ifdef DEBUG |
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if (o->set) { |
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log_puts("timo_add: already set\n"); |
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panic(); |
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} |
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if (delta == 0) { |
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log_puts("timo_add: zero timeout is evil\n"); |
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panic(); |
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} |
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#endif |
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val = timo_abstime + delta; |
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for (i = &timo_queue; *i != NULL; i = &(*i)->next) { |
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diff = (*i)->val - val; |
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if (diff > 0) { |
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break; |
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} |
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} |
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o->set = 1; |
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o->val = val; |
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o->next = *i; |
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*i = o; |
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} |
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/* |
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* abort a scheduled timeout |
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*/ |
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void |
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timo_del(struct timo *o) |
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{ |
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struct timo **i; |
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for (i = &timo_queue; *i != NULL; i = &(*i)->next) { |
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if (*i == o) { |
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*i = o->next; |
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o->set = 0; |
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return; |
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} |
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} |
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#ifdef DEBUG |
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if (log_level >= 4) |
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log_puts("timo_del: not found\n"); |
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#endif |
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} |
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/* |
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* routine to be called by the timer when 'delta' 24-th of microsecond |
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* elapsed. This routine updates time referece used by timeouts and |
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* calls expired timeouts |
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*/ |
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void |
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timo_update(unsigned int delta) |
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{ |
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struct timo *to; |
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int diff; |
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/* |
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* update time reference |
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*/ |
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timo_abstime += delta; |
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/* |
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* remove from the queue and run expired timeouts |
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*/ |
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while (timo_queue != NULL) { |
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/* |
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* there is no overflow here because + and - are |
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* modulo 2^32, they are the same for both signed and |
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* unsigned integers |
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*/ |
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diff = timo_queue->val - timo_abstime; |
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if (diff > 0) |
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break; |
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to = timo_queue; |
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timo_queue = to->next; |
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to->set = 0; |
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to->cb(to->arg); |
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} |
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} |
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/* |
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* initialize timeout queue |
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*/ |
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void |
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timo_init(void) |
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{ |
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timo_queue = NULL; |
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timo_abstime = 0; |
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} |
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/* |
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* destroy timeout queue |
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*/ |
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void |
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timo_done(void) |
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{ |
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#ifdef DEBUG |
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if (timo_queue != NULL) { |
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log_puts("timo_done: timo_queue not empty!\n"); |
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panic(); |
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} |
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#endif |
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timo_queue = (struct timo *)0xdeadbeef; |
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} |
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#ifdef DEBUG |
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void |
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file_log(struct file *f) |
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{ |
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static char *states[] = { "ini", "zom" }; |
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log_puts(f->ops->name); |
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if (log_level >= 3) { |
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log_puts("("); |
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log_puts(f->name); |
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log_puts("|"); |
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log_puts(states[f->state]); |
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log_puts(")"); |
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} |
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} |
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#endif |
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struct file * |
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file_new(struct fileops *ops, void *arg, char *name, unsigned int nfds) |
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{ |
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struct file *f; |
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if (file_nfds + nfds > MAXFDS) { |
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#ifdef DEBUG |
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if (log_level >= 1) { |
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log_puts(name); |
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log_puts(": too many polled files\n"); |
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} |
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#endif |
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return NULL; |
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} |
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f = xmalloc(sizeof(struct file)); |
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f->max_nfds = nfds; |
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f->ops = ops; |
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f->arg = arg; |
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f->name = name; |
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f->state = FILE_INIT; |
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f->next = file_list; |
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file_list = f; |
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#ifdef DEBUG |
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if (log_level >= 3) { |
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file_log(f); |
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log_puts(": created\n"); |
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} |
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#endif |
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file_nfds += f->max_nfds; |
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return f; |
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} |
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void |
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file_del(struct file *f) |
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{ |
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#ifdef DEBUG |
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if (f->state == FILE_ZOMB) { |
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log_puts("bad state in file_del()\n"); |
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panic(); |
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} |
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#endif |
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file_nfds -= f->max_nfds; |
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f->state = FILE_ZOMB; |
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#ifdef DEBUG |
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if (log_level >= 3) { |
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file_log(f); |
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log_puts(": destroyed\n"); |
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} |
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#endif |
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} |
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void |
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file_process(struct file *f, struct pollfd *pfd) |
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{ |
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int revents; |
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#ifdef DEBUG |
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struct timespec ts0, ts1; |
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long us; |
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#endif |
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#ifdef DEBUG |
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if (log_level >= 3) |
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clock_gettime(CLOCK_UPTIME, &ts0); |
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#endif |
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revents = (f->state != FILE_ZOMB) ? |
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f->ops->revents(f->arg, pfd) : 0; |
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if ((revents & POLLHUP) && (f->state != FILE_ZOMB)) |
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f->ops->hup(f->arg); |
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if ((revents & POLLIN) && (f->state != FILE_ZOMB)) |
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f->ops->in(f->arg); |
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if ((revents & POLLOUT) && (f->state != FILE_ZOMB)) |
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f->ops->out(f->arg); |
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#ifdef DEBUG |
294 |
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if (log_level >= 3) { |
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clock_gettime(CLOCK_UPTIME, &ts1); |
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us = 1000000L * (ts1.tv_sec - ts0.tv_sec); |
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us += (ts1.tv_nsec - ts0.tv_nsec) / 1000; |
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if (log_level >= 4 || us >= 5000) { |
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file_log(f); |
300 |
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log_puts(": processed in "); |
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log_putu(us); |
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log_puts("us\n"); |
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} |
304 |
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} |
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#endif |
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} |
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int |
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file_poll(void) |
310 |
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{ |
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struct pollfd pfds[MAXFDS], *pfd; |
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struct file *f, **pf; |
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struct timespec ts; |
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#ifdef DEBUG |
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struct timespec sleepts; |
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int i; |
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#endif |
318 |
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long long delta_nsec; |
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int nfds, res, timo; |
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/* |
322 |
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* cleanup zombies |
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*/ |
324 |
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pf = &file_list; |
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while ((f = *pf) != NULL) { |
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if (f->state == FILE_ZOMB) { |
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*pf = f->next; |
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xfree(f); |
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} else |
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pf = &f->next; |
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} |
332 |
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333 |
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if (file_list == NULL && timo_queue == NULL) { |
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#ifdef DEBUG |
335 |
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if (log_level >= 3) |
336 |
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log_puts("nothing to do...\n"); |
337 |
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#endif |
338 |
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return 0; |
339 |
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} |
340 |
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341 |
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/* |
342 |
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* fill pollfd structures |
343 |
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*/ |
344 |
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nfds = 0; |
345 |
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for (f = file_list; f != NULL; f = f->next) { |
346 |
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f->nfds = f->ops->pollfd(f->arg, pfds + nfds); |
347 |
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if (f->nfds == 0) |
348 |
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continue; |
349 |
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nfds += f->nfds; |
350 |
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} |
351 |
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#ifdef DEBUG |
352 |
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if (log_level >= 4) { |
353 |
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log_puts("poll:"); |
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pfd = pfds; |
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for (f = file_list; f != NULL; f = f->next) { |
356 |
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log_puts(" "); |
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log_puts(f->ops->name); |
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log_puts(":"); |
359 |
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for (i = 0; i < f->nfds; i++) { |
360 |
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log_puts(" "); |
361 |
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log_putx(pfd->events); |
362 |
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pfd++; |
363 |
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} |
364 |
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} |
365 |
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log_puts("\n"); |
366 |
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} |
367 |
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#endif |
368 |
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369 |
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/* |
370 |
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* process files that do not rely on poll |
371 |
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*/ |
372 |
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for (f = file_list; f != NULL; f = f->next) { |
373 |
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if (f->nfds > 0) |
374 |
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continue; |
375 |
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file_process(f, NULL); |
376 |
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} |
377 |
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378 |
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/* |
379 |
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* Sleep. Calculate the number off milliseconds poll(2) must |
380 |
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* wait before the timo_update() needs to be called. If there're |
381 |
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* no timeouts scheduled, then call poll(2) with infinite |
382 |
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* timeout (i.e -1). |
383 |
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*/ |
384 |
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#ifdef DEBUG |
385 |
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clock_gettime(CLOCK_UPTIME, &sleepts); |
386 |
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file_utime += 1000000000LL * (sleepts.tv_sec - file_ts.tv_sec); |
387 |
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file_utime += sleepts.tv_nsec - file_ts.tv_nsec; |
388 |
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#endif |
389 |
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if (timo_queue != NULL) { |
390 |
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timo = ((int)timo_queue->val - (int)timo_abstime) / 1000; |
391 |
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if (timo < TIMER_MSEC) |
392 |
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timo = TIMER_MSEC; |
393 |
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} else |
394 |
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timo = -1; |
395 |
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log_flush(); |
396 |
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res = poll(pfds, nfds, timo); |
397 |
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if (res < 0) { |
398 |
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if (errno != EINTR) { |
399 |
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log_puts("poll failed"); |
400 |
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panic(); |
401 |
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} |
402 |
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return 1; |
403 |
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} |
404 |
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|
405 |
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/* |
406 |
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* run timeouts |
407 |
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*/ |
408 |
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clock_gettime(CLOCK_UPTIME, &ts); |
409 |
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#ifdef DEBUG |
410 |
|
|
file_wtime += 1000000000LL * (ts.tv_sec - sleepts.tv_sec); |
411 |
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|
file_wtime += ts.tv_nsec - sleepts.tv_nsec; |
412 |
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#endif |
413 |
|
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if (timo_queue) { |
414 |
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delta_nsec = 1000000000LL * (ts.tv_sec - file_ts.tv_sec); |
415 |
|
|
delta_nsec += ts.tv_nsec - file_ts.tv_nsec; |
416 |
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|
if (delta_nsec >= 0 && delta_nsec < 60000000000LL) |
417 |
|
|
timo_update(delta_nsec / 1000); |
418 |
|
|
else { |
419 |
|
|
if (log_level >= 2) |
420 |
|
|
log_puts("out-of-bounds clock delta\n"); |
421 |
|
|
} |
422 |
|
|
} |
423 |
|
|
file_ts = ts; |
424 |
|
|
|
425 |
|
|
/* |
426 |
|
|
* process files that rely on poll |
427 |
|
|
*/ |
428 |
|
|
pfd = pfds; |
429 |
|
|
for (f = file_list; f != NULL; f = f->next) { |
430 |
|
|
if (f->nfds == 0) |
431 |
|
|
continue; |
432 |
|
|
file_process(f, pfd); |
433 |
|
|
pfd += f->nfds; |
434 |
|
|
} |
435 |
|
|
return 1; |
436 |
|
|
} |
437 |
|
|
|
438 |
|
|
void |
439 |
|
|
filelist_init(void) |
440 |
|
|
{ |
441 |
|
|
sigset_t set; |
442 |
|
|
|
443 |
|
|
if (clock_gettime(CLOCK_UPTIME, &file_ts) < 0) { |
444 |
|
|
log_puts("filelist_init: CLOCK_UPTIME unsupported\n"); |
445 |
|
|
panic(); |
446 |
|
|
} |
447 |
|
|
sigemptyset(&set); |
448 |
|
|
sigaddset(&set, SIGPIPE); |
449 |
|
|
sigprocmask(SIG_BLOCK, &set, NULL); |
450 |
|
|
file_list = NULL; |
451 |
|
|
log_sync = 0; |
452 |
|
|
timo_init(); |
453 |
|
|
} |
454 |
|
|
|
455 |
|
|
void |
456 |
|
|
filelist_done(void) |
457 |
|
|
{ |
458 |
|
|
#ifdef DEBUG |
459 |
|
|
struct file *f; |
460 |
|
|
|
461 |
|
|
if (file_list != NULL) { |
462 |
|
|
for (f = file_list; f != NULL; f = f->next) { |
463 |
|
|
file_log(f); |
464 |
|
|
log_puts(" not closed\n"); |
465 |
|
|
} |
466 |
|
|
panic(); |
467 |
|
|
} |
468 |
|
|
log_sync = 1; |
469 |
|
|
log_flush(); |
470 |
|
|
#endif |
471 |
|
|
timo_done(); |
472 |
|
|
} |