lib/libasyn/asyn_write.c

   1 /*      asyn_write()                                    Author: Kees J. Bot
   2  *                                                              7 Jul 1997
   3  */
   4 #include "asyn.h"
   5 #include <signal.h>
   6
   7 ssize_t asyn_write(asynchio_t *asyn, int fd, const void *buf, size_t len)
   8 /* Nonblocking write().  (See asyn_read()). */
   9 {
  10         asynfd_t *afd;
  11
  12         asyn->asyn_more++;
  13
  14         if ((unsigned) fd >= FD_SETSIZE) { errno= EBADF; return -1; }
  15         afd= &asyn->asyn_afd[fd];
  16
  17         if (!afd->afd_seen) {
  18                 if ((afd->afd_flags= fcntl(fd, F_GETFL)) < 0) return -1;
  19                 afd->afd_seen= 1;
  20         }
  21
  22         if (afd->afd_state[SEL_WRITE] == PENDING) {
  23                 sigset_t mask;
  24                 ssize_t result;
  25                 int err;
  26
  27                 sigemptyset(&mask);
  28                 if (sigprocmask(SIG_SETMASK, &mask, &mask) < 0) return -1;
  29                 (void) fcntl(fd, F_SETFL, afd->afd_flags | O_NONBLOCK);
  30
  31                 result= write(fd, buf, len);
  32                 err= errno;
  33
  34                 (void) fcntl(fd, F_SETFL, afd->afd_flags);
  35                 (void) sigprocmask(SIG_SETMASK, &mask, nil);
  36
  37                 errno= err;
  38                 if (result != -1 || errno != EAGAIN) {
  39                         afd->afd_state[SEL_WRITE]= IDLE;
  40                         return result;
  41                 }
  42         }
  43
  44         afd->afd_state[SEL_WRITE]= WAITING;
  45         FD_SET(fd, &asyn->asyn_fdset[SEL_WRITE]);
  46         errno= EAGAIN;
  47         asyn->asyn_more--;
  48         return -1;
  49 }