diff options
Diffstat (limited to 'lib/util')
| -rw-r--r-- | lib/util/select.c | 90 | ||||
| -rw-r--r-- | lib/util/select.h | 1 |
2 files changed, 0 insertions, 91 deletions
diff --git a/lib/util/select.c b/lib/util/select.c index 63be55cf0c..5e66344c9d 100644 --- a/lib/util/select.c +++ b/lib/util/select.c @@ -23,96 +23,6 @@ #include "system/select.h" #include "lib/util/select.h" -/* This is here because it allows us to avoid a nasty race in signal handling. - We need to guarantee that when we get a signal we get out of a select immediately - but doing that involves a race condition. We can avoid the race by getting the - signal handler to write to a pipe that is in the select/poll list - - This means all Samba signal handlers should call sys_select_signal(). -*/ - -static pid_t initialised; -static int select_pipe[2]; -static volatile unsigned pipe_written, pipe_read; - -/* - * sys_poll expects pollfd's to be a talloc'ed array. - * - * It expects the talloc_array_length(fds) >= num_fds+1 to give space - * to the signal pipe. - */ - -int sys_poll(struct pollfd *fds, int num_fds, int timeout) -{ - int ret; - - if (talloc_array_length(fds) < num_fds+1) { - errno = ENOSPC; - return -1; - } - - if (initialised != sys_getpid()) { - if (pipe(select_pipe) == -1) - { - int saved_errno = errno; - DEBUG(0, ("sys_poll: pipe failed (%s)\n", - strerror(errno))); - errno = saved_errno; - return -1; - } - - /* - * These next two lines seem to fix a bug with the Linux - * 2.0.x kernel (and probably other UNIXes as well) where - * the one byte read below can block even though the - * select returned that there is data in the pipe and - * the pipe_written variable was incremented. Thanks to - * HP for finding this one. JRA. - */ - - if(set_blocking(select_pipe[0],0)==-1) - smb_panic("select_pipe[0]: O_NONBLOCK failed"); - if(set_blocking(select_pipe[1],0)==-1) - smb_panic("select_pipe[1]: O_NONBLOCK failed"); - - initialised = sys_getpid(); - } - - ZERO_STRUCT(fds[num_fds]); - fds[num_fds].fd = select_pipe[0]; - fds[num_fds].events = POLLIN|POLLHUP; - - errno = 0; - ret = poll(fds, num_fds+1, timeout); - - if ((ret >= 0) && (fds[num_fds].revents & (POLLIN|POLLHUP|POLLERR))) { - char c; - int saved_errno = errno; - - if (read(select_pipe[0], &c, 1) == 1) { - pipe_read += 1; - - /* Mark Weaver <mark-clist@npsl.co.uk> pointed out a critical - fix to ensure we don't lose signals. We must always - return -1 when the select pipe is set, otherwise if another - fd is also ready (so ret == 2) then we used to eat the - byte in the pipe and lose the signal. JRA. - */ - ret = -1; -#if 0 - /* JRA - we can use this to debug the signal messaging... */ - DEBUG(0,("select got %u signal\n", (unsigned int)c)); -#endif - errno = EINTR; - } else { - ret -= 1; - errno = saved_errno; - } - } - - return ret; -} - int sys_poll_intr(struct pollfd *fds, int num_fds, int timeout) { int orig_timeout = timeout; diff --git a/lib/util/select.h b/lib/util/select.h index bfc78a99d2..fa1970ec01 100644 --- a/lib/util/select.h +++ b/lib/util/select.h @@ -24,7 +24,6 @@ /* The following definitions come from lib/util/select.c */ -int sys_poll(struct pollfd *fds, int num_fds, int timeout); int sys_poll_intr(struct pollfd *fds, int num_fds, int timeout); #endif |