You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
51 lines
1.1 KiB
C
51 lines
1.1 KiB
C
#include <unistd.h>
|
|
#include <sys/time.h>
|
|
#include <poll.h>
|
|
#include <errno.h>
|
|
#include "io_internal.h"
|
|
|
|
int64 io_tryread(int64 d,char* buf,int64 len) {
|
|
long r;
|
|
struct itimerval old,new;
|
|
struct pollfd p;
|
|
io_entry* e=array_get(&io_fds,sizeof(io_entry),d);
|
|
if (!e) { errno=EBADF; return -3; }
|
|
if (!e->nonblock) {
|
|
p.fd=d;
|
|
if (p.fd != d) { errno=EBADF; return -3; } /* catch overflow */
|
|
p.events=POLLIN;
|
|
switch (poll(&p,1,0)) {
|
|
case -1: return -3;
|
|
case 0: errno=EAGAIN;
|
|
e->canread=0;
|
|
e->next_read=-1;
|
|
return -1;
|
|
}
|
|
new.it_interval.tv_usec=0;
|
|
new.it_interval.tv_sec=0;
|
|
new.it_value.tv_usec=10000;
|
|
new.it_value.tv_sec=0;
|
|
setitimer(ITIMER_REAL,&new,&old);
|
|
}
|
|
r=read(d,buf,len);
|
|
if (!e->nonblock) {
|
|
setitimer(ITIMER_REAL,&old,0);
|
|
}
|
|
if (r==-1) {
|
|
if (errno==EINTR) errno=EAGAIN;
|
|
if (errno!=EAGAIN)
|
|
r=-3;
|
|
}
|
|
if (r==-1 || r==0) {
|
|
e->canread=0;
|
|
#ifdef HAVE_SIGIO
|
|
if (d==alt_firstread) {
|
|
debug_printf(("io_tryread: dequeueing %ld from alt read queue (next is %ld)\n",d,e->next_read));
|
|
alt_firstread=e->next_read;
|
|
}
|
|
#endif
|
|
e->next_read=-1;
|
|
}
|
|
return r;
|
|
}
|