Fix from Michael Steffens <michael_steffens@hp.com> to make signal

[abartlet/samba.git/.git] / source3 / lib / select.c

diff --git a/source3/lib/select.c b/source3/lib/select.c
index 5e85d113513f1d253c8f3db33a71d0f6fd80dbd5..f70268b7ce47c7cac8019b71758a46df54a48037 100644 (file)
--- a/source3/lib/select.c
+++ b/source3/lib/select.c
@@ -1,5 +1,6 @@
 /* 
-   Unix SMB/CIFS implementation.
+   Unix SMB/Netbios implementation.
+   Version 3.0
    Samba select/poll implementation
    Copyright (C) Andrew Tridgell 1992-1998
    
@@ -20,22 +21,23 @@
 
 #include "includes.h"
 
-/* this is here because it allows us to avoid a nasty race in signal handling. 
+/* 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()
+   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;
 
-
 /*******************************************************************
-call this from all Samba signal handlers if you want to avoid a 
-nasty signal race condition
+ Call this from all Samba signal handlers if you want to avoid a 
+ nasty signal race condition.
 ********************************************************************/
+
 void sys_select_signal(void)
 {
        char c = 1;
@@ -47,13 +49,15 @@ void sys_select_signal(void)
 }
 
 /*******************************************************************
-like select() but avoids the signal race using a pipe
-it also guarantees that fds on return only ever contains bits set
-for file descriptors that were readable
+ Like select() but avoids the signal race using a pipe
+ it also guuarantees that fds on return only ever contains bits set
+ for file descriptors that were readable.
 ********************************************************************/
-int sys_select(int maxfd, fd_set *fds,struct timeval *tval)
+
+int sys_select(int maxfd, fd_set *readfds, fd_set *writefds, fd_set *errorfds, struct timeval *tval)
 {
        int ret, saved_errno;
+       fd_set *readfds2, readfds_buf;
 
        if (initialised != sys_getpid()) {
                pipe(select_pipe);
@@ -76,16 +80,29 @@ int sys_select(int maxfd, fd_set *fds,struct timeval *tval)
        }
 
        maxfd = MAX(select_pipe[0]+1, maxfd);
-       FD_SET(select_pipe[0], fds);
+
+       /* If readfds is NULL we need to provide our own set. */
+       if (readfds) {
+               readfds2 = readfds;
+       } else {
+               readfds2 = &readfds_buf;
+               FD_ZERO(readfds2);
+       }
+       FD_SET(select_pipe[0], readfds2);
+
        errno = 0;
-       ret = select(maxfd,fds,NULL,NULL,tval);
+       ret = select(maxfd,readfds2,writefds,errorfds,tval);
 
        if (ret <= 0) {
-               FD_ZERO(fds);
+               FD_ZERO(readfds2);
+               if (writefds)
+                       FD_ZERO(writefds);
+               if (errorfds)
+                       FD_ZERO(errorfds);
        }
 
-       if (FD_ISSET(select_pipe[0], fds)) {
-               FD_CLR(select_pipe[0], fds);
+       if (FD_ISSET(select_pipe[0], readfds2)) {
+               FD_CLR(select_pipe[0], readfds2);
                ret--;
                if (ret == 0) {
                        ret = -1;
@@ -109,20 +126,35 @@ int sys_select(int maxfd, fd_set *fds,struct timeval *tval)
 }
 
 /*******************************************************************
-similar to sys_select() but catch EINTR and continue
-this is what sys_select() used to do in Samba
+ Similar to sys_select() but catch EINTR and continue.
+ This is what sys_select() used to do in Samba.
 ********************************************************************/
-int sys_select_intr(int maxfd, fd_set *fds,struct timeval *tval)
+
+int sys_select_intr(int maxfd, fd_set *readfds, fd_set *writefds, fd_set *errorfds, struct timeval *tval)
 {
        int ret;
-       fd_set fds2;
+       fd_set *readfds2, readfds_buf, *writefds2, writefds_buf, *errorfds2, errorfds_buf;
+
+       readfds2 = (readfds ? &readfds_buf : NULL);
+       writefds2 = (writefds ? &writefds_buf : NULL);
+       errorfds2 = (errorfds ? &errorfds_buf : NULL);
 
        do {
-               fds2 = *fds;
-               ret = sys_select(maxfd, &fds2, tval);
+               if (readfds)
+                       readfds_buf = *readfds;
+               if (writefds)
+                       writefds_buf = *writefds;
+               if (errorfds)
+                       errorfds_buf = *errorfds;
+               ret = sys_select(maxfd, readfds2, writefds2, errorfds2, tval);
        } while (ret == -1 && errno == EINTR);
 
-       *fds = fds2;
+       if (readfds)
+               *readfds = readfds_buf;
+       if (writefds)
+               *writefds = writefds_buf;
+       if (errorfds)
+               *errorfds = errorfds_buf;
 
        return ret;
 }