Kannel: Open Source WAP and SMS gateway  $Revision: 5037 $
gwpoll.c File Reference
#include "gwlib/gwlib.h"
#include <sys/time.h>
#include <sys/types.h>
#include <unistd.h>

Go to the source code of this file.

Functions

int gw_poll (struct pollfd *fdarray, unsigned int numfds, int timeout)
 

Function Documentation

int gw_poll ( struct pollfd fdarray,
unsigned int  numfds,
int  timeout 
)

Definition at line 67 of file gwpoll.c.

References pollfd::events, pollfd::fd, POLLIN, POLLNVAL, POLLOUT, POLLPRI, and pollfd::revents.

68 {
69  struct timeval tv, *tvp;
70  unsigned int i;
71  int maxfd;
72  fd_set readfds, *rfdp;
73  fd_set writefds, *wfdp;
74  fd_set exceptfds, *xfdp;
75  int ret;
76  int result;
77 
78  FD_ZERO(&readfds);
79  FD_ZERO(&writefds);
80  FD_ZERO(&exceptfds);
81  maxfd = -1;
82  /* These are the pointers we will pass to select(). We use them because
83  * we may want to pass NULL for some of them. */
84  tvp = NULL;
85  rfdp = NULL;
86  wfdp = NULL;
87  xfdp = NULL;
88 
89  /* Deal with timeout. We get it in milliseconds. If it's negative,
90  * block indefinitely, which we do in select() by passing a NULL
91  * timeval pointer. */
92  if (timeout >= 0) {
93  tv.tv_sec = timeout / 1000;
94  tv.tv_usec = (timeout % 1000) * 1000;
95  tvp = &tv;
96  }
97 
98  /* Deal with fdarray, and convert it to the three fd_sets used by select. */
99  for (i = 0; i < numfds; i++) {
100  int fd = fdarray[i].fd;
101  int events = fdarray[i].events;
102  if (fd < 0)
103  continue;
104  if (events & POLLIN) {
105  FD_SET(fd, &readfds);
106  rfdp = &readfds;
107  }
108  if (events & POLLOUT) {
109  FD_SET(fd, &writefds);
110  wfdp = &writefds;
111  }
112  if (events & POLLPRI) {
113  FD_SET(fd, &exceptfds);
114  xfdp = &exceptfds;
115  }
116  if (fd > maxfd && events & (POLLIN | POLLOUT | POLLPRI))
117  maxfd = fd;
118  }
119 
120  ret = select(maxfd + 1, rfdp, wfdp, xfdp, tvp);
121  if (ret < 0)
122  return ret;
123 
124  /* Move the returned data from the fd sets to the revents fields
125  * in fdarray. We can't detect POLLNVAL except for obviously
126  * invalid fd's, and detecting POLLHUP or POLLERR would require
127  * an extra read() call per fd which is too expensive. */
128  result = 0;
129  for (i = 0; i < numfds; i++) {
130  if (fdarray[i].fd < 0) {
131  fdarray[i].revents = POLLNVAL;
132  continue;
133  }
134  fdarray[i].revents = 0;
135  if (rfdp && FD_ISSET(fdarray[i].fd, &readfds))
136  fdarray[i].revents |= POLLIN;
137  if (wfdp && FD_ISSET(fdarray[i].fd, &writefds))
138  fdarray[i].revents |= POLLOUT;
139  if (xfdp && FD_ISSET(fdarray[i].fd, &exceptfds))
140  fdarray[i].revents |= POLLPRI;
141  if (fdarray[i].revents != 0)
142  result++;
143  }
144 
145  return result;
146 }
#define POLLNVAL
Definition: gwpoll.h:98
short events
Definition: gwpoll.h:86
#define POLLPRI
Definition: gwpoll.h:92
#define POLLIN
Definition: gwpoll.h:91
int fd
Definition: gwpoll.h:85
short revents
Definition: gwpoll.h:87
#define POLLOUT
Definition: gwpoll.h:93
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