int acl_master_flow_count(void)
{
char myname[] = "acl_master_flow_count";
int count;
if ((count = acl_peekfd(ACL_MASTER_FLOW_READ)) < 0)
acl_msg_warn("%s: %s", myname, strerror(errno));
return (count);
}
int acl_fifo_listen(const char *path, int permissions, int block_mode)
{
char *myname = "acl_fifo_listen";
char buf[BUF_LEN], tbuf[256];
static int open_mode = 0;
struct stat st;
int fd;
int count;
/*
* Create a named pipe (fifo). Do whatever we can so we don't run into
* trouble when this process is restarted after crash. Make sure that
* we open a fifo and not something else, then change permissions to
* what we wanted them to be, because mkfifo() is subject to umask
* settings. Instead we could zero the umask temporarily before
* creating the FIFO, but that would cost even more system calls.
* Figure out if the fifo needs to be opened O_RDWR or O_RDONLY. Some
* systems need one, some need the other. If we choose the wrong mode,
* the fifo will stay readable, causing the program to go into a loop.
*/
if (unlink(path) && acl_last_error() != ENOENT) {
acl_msg_error("%s: remove %s: %s", myname, path,
acl_last_strerror(tbuf, sizeof(tbuf)));
return -1;
}
if (mkfifo(path, permissions) < 0) {
acl_msg_error("%s: create fifo %s: %s", myname, path,
acl_last_strerror(tbuf, sizeof(tbuf)));
return -1;
}
switch (open_mode) {
case 0:
if ((fd = open(path, O_RDWR | O_NONBLOCK, 0)) < 0) {
acl_msg_error("%s: open %s: %s", myname, path,
acl_last_strerror(tbuf, sizeof(tbuf)));
return -1;
}
if (acl_readable(fd) == 0) {
open_mode = O_RDWR | O_NONBLOCK;
break;
}
open_mode = O_RDONLY | O_NONBLOCK;
if (acl_msg_verbose)
acl_msg_info("open O_RDWR makes fifo readable"
" - trying O_RDONLY");
(void) close(fd);
if ((fd = open(path, open_mode, 0)) < 0) {
acl_msg_error("%s: open %s: %s", myname, path,
acl_last_strerror(tbuf, sizeof(tbuf)));
return -1;
}
break;
default:
if ((fd = open(path, open_mode, 0)) < 0) {
acl_msg_error("%s: open %s: %s", myname, path,
acl_last_strerror(tbuf, sizeof(tbuf)));
return -1;
}
break;
}
/*
* Make sure we opened a FIFO and skip any cruft that might have
* accumulated before we opened it.
*/
if (fstat(fd, &st) < 0) {
acl_msg_error("%s: fstat %s: %s", myname, path,
acl_last_strerror(tbuf, sizeof(tbuf)));
close(fd);
return -1;
}
if (S_ISFIFO(st.st_mode) == 0) {
acl_msg_error("%s: not a fifo: %s", myname, path);
close(fd);
return -1;
}
if (fchmod(fd, permissions) < 0) {
acl_msg_error("%s: fchmod %s: %s", myname, path,
acl_last_strerror(tbuf, sizeof(tbuf)));
close(fd);
return -1;
}
acl_non_blocking(fd, block_mode);
while ((count = acl_peekfd(fd)) > 0 && read(fd, buf,
BUF_LEN < count ? BUF_LEN : count) > 0) {
}
return fd;
}
