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/* signal.c, liboop, copyright 1999 Dan Egnor
This is free software; you can redistribute it and/or modify it under the
terms of the GNU Lesser General Public License, version 2.1 or later.
See the file COPYING for details. */
#include "oop.h"
#include <assert.h>
#include <signal.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
#define MAGIC 5131
struct sig_handler {
struct sig_handler *next;
oop_call_signal *f;
void *v;
};
struct sig_signal {
struct sig_handler *list,*ptr;
struct sigaction old;
volatile sig_atomic_t active;
};
struct oop_adapter_signal {
oop_source oop;
int magic,pipefd[2];
oop_source *source; /* backing source */
struct sig_signal sig[OOP_NUM_SIGNALS];
int num_events;
int use_sa_restart;
};
static struct oop_adapter_signal *sig_owner[OOP_NUM_SIGNALS];
static oop_adapter_signal *verify_source(oop_source *source) {
oop_adapter_signal * const s = (oop_adapter_signal *) source;
assert(MAGIC == s->magic);
return s;
}
static void do_pipe(struct oop_adapter_signal *s) {
const char ch = '\0';
while (write(s->pipefd[1],&ch,1) < 0 && EINTR == errno) ;
}
static void on_signal(int sig) {
oop_adapter_signal * const s = sig_owner[sig];
struct sigaction act;
assert(NULL != s);
/* Reset the handler, in case this is needed. */
sigaction(sig,NULL,&act);
act.sa_handler = on_signal;
sigaction(sig,&act,NULL);
assert(NULL != s->sig[sig].list);
s->sig[sig].active = 1;
do_pipe(s);
}
static void *on_pipe(oop_source *source,int fd,oop_event event,void *user) {
oop_adapter_signal * const s = verify_source((oop_source *) user);
int i;
char buf[4096];
assert(fd == s->pipefd[0]);
assert(OOP_READ == event);
while (read(s->pipefd[0],buf,sizeof buf) < 0 && EINTR == errno) ;
for (i = 0; i < OOP_NUM_SIGNALS; ++i) {
if (s->sig[i].active) {
s->sig[i].active = 0;
s->sig[i].ptr = s->sig[i].list;
}
if (NULL != s->sig[i].ptr) {
struct sig_handler * const h = s->sig[i].ptr;
s->sig[i].ptr = h->next;
do_pipe(s); /* come back */
return h->f(&s->oop,i,h->v);
}
}
return OOP_CONTINUE;
}
static void sig_on_fd(oop_source *source,int fd,oop_event ev,
oop_call_fd *call,void *data) {
oop_adapter_signal * const s = verify_source(source);
s->source->on_fd(s->source,fd,ev,call,data);
}
static void sig_cancel_fd(oop_source *source,int fd,oop_event ev) {
oop_adapter_signal * const s = verify_source(source);
s->source->cancel_fd(s->source,fd,ev);
}
static void sig_on_time(oop_source *source,struct timeval when,
oop_call_time *call,void *data) {
oop_adapter_signal * const s = verify_source(source);
s->source->on_time(s->source,when,call,data);
}
static void sig_cancel_time(oop_source *source,struct timeval when,
oop_call_time *call,void *data) {
oop_adapter_signal * const s = verify_source(source);
s->source->cancel_time(s->source,when,call,data);
}
static void sig_on_signal(oop_source *source,int sig,
oop_call_signal *f,void *v) {
oop_adapter_signal * const s = verify_source(source);
struct sig_handler * const handler = oop_malloc(sizeof(*handler));
if (NULL == handler) return; /* ugh */
assert(sig > 0 && sig < OOP_NUM_SIGNALS && "invalid signal number");
handler->f = f;
handler->v = v;
handler->next = s->sig[sig].list;
s->sig[sig].list = handler;
++s->num_events;
if (NULL == handler->next) {
struct sigaction act;
assert(NULL == sig_owner[sig]);
sig_owner[sig] = s;
assert(0 == s->sig[sig].active);
sigaction(sig,NULL,&act);
s->sig[sig].old = act;
act.sa_handler = on_signal;
#ifdef SA_NODEFER
act.sa_flags &= ~SA_NODEFER;
#endif
if (s->use_sa_restart) act.sa_flags |= SA_RESTART;
sigaction(sig,&act,NULL);
}
}
static void sig_cancel_signal(oop_source *source,int sig,
oop_call_signal *f,void *v) {
oop_adapter_signal * const s = verify_source(source);
struct sig_handler **pp = &s->sig[sig].list;
assert(sig > 0 && sig < OOP_NUM_SIGNALS && "invalid signal number");
while (NULL != *pp && ((*pp)->f != f || (*pp)->v != v))
pp = &(*pp)->next;
if (NULL != *pp) {
struct sig_handler * const p = *pp;
if (NULL == p->next && &s->sig[sig].list == pp) {
sigaction(sig,&s->sig[sig].old,NULL);
s->sig[sig].active = 0;
sig_owner[sig] = NULL;
}
*pp = p->next;
if (s->sig[sig].ptr == p) s->sig[sig].ptr = *pp;
--s->num_events;
oop_free(p);
}
}
static int fcntl_flag(int fd, int get_op, int set_op, int val) {
const int flags = fcntl(fd,get_op,0);
if (flags < 0) return -1;
return fcntl(fd,set_op,flags|val);
}
oop_adapter_signal *oop_signal_new_flags(oop_source *source, int flags) {
int i;
oop_adapter_signal * const s = oop_malloc(sizeof(*s));
if (NULL == s) return NULL;
assert(NULL != source);
if (pipe(s->pipefd)
|| fcntl_flag(s->pipefd[0],F_GETFD,F_SETFD,FD_CLOEXEC)
|| fcntl_flag(s->pipefd[1],F_GETFD,F_SETFD,FD_CLOEXEC)
|| fcntl_flag(s->pipefd[0],F_GETFL,F_SETFL,O_NONBLOCK)
|| fcntl_flag(s->pipefd[1],F_GETFL,F_SETFL,O_NONBLOCK)) {
oop_free(s);
return NULL;
}
s->oop.on_fd = sig_on_fd;
s->oop.cancel_fd = sig_cancel_fd;
s->oop.on_time = sig_on_time;
s->oop.cancel_time = sig_cancel_time;
s->oop.on_signal = sig_on_signal;
s->oop.cancel_signal = sig_cancel_signal;
s->source = source;
s->source->on_fd(s->source,s->pipefd[0],OOP_READ,on_pipe,s);
s->num_events = 0;
for (i = 0; i < OOP_NUM_SIGNALS; ++i) {
s->sig[i].list = NULL;
s->sig[i].ptr = NULL;
s->sig[i].active = 0;
}
if (flags & OOP_SIGNAL_USE_RESTART) {
s->use_sa_restart = 1;
}
s->magic = MAGIC;
return s;
}
oop_adapter_signal *oop_signal_new(oop_source *source) {
return oop_signal_new_flags(source, 0);
}
void oop_signal_delete(oop_adapter_signal *s) {
assert(0 == s->num_events && "cannot delete with signal handler");
s->magic = 0;
close(s->pipefd[0]);
close(s->pipefd[1]);
s->source->cancel_fd(s->source,s->pipefd[0],OOP_READ);
oop_free(s);
}
oop_source *oop_signal_source(oop_adapter_signal *s) {
return &s->oop;
}
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