From 69adbb0ce3bb9d5bd569c13aaa3ac8f390c1586a Mon Sep 17 00:00:00 2001 From: Jeremy Allison Date: Thu, 31 Jan 2002 23:26:12 +0000 Subject: Fix from Michael Steffens to make signal processing work correctly in winbindd. This is a really good patch that gives full select semantics to the Samba modified select. Jeremy. (This used to be commit 3af16ade173cac24c1ac5eff4a36b439f16ac036) --- source3/lib/readline.c | 2 +- source3/lib/select.c | 76 +++++++++++++++++++++++++++++++++++-------------- source3/lib/util.c | 2 +- source3/lib/util_sock.c | 4 +-- 4 files changed, 58 insertions(+), 26 deletions(-) (limited to 'source3/lib') diff --git a/source3/lib/readline.c b/source3/lib/readline.c index 013b8516f8..d80c571dd3 100644 --- a/source3/lib/readline.c +++ b/source3/lib/readline.c @@ -51,7 +51,7 @@ static char *smb_readline_replacement(char *prompt, void (*callback)(void), FD_ZERO(&fds); FD_SET(fd,&fds); - if (sys_select_intr(fd+1,&fds,&timeout) == 1) { + if (sys_select_intr(fd+1,&fds,NULL,NULL,&timeout) == 1) { ret = fgets(line, sizeof(line), stdin); return ret; } diff --git a/source3/lib/select.c b/source3/lib/select.c index 5e85d11351..f70268b7ce 100644 --- 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; } diff --git a/source3/lib/util.c b/source3/lib/util.c index 9d000c80f0..8867d37d57 100644 --- a/source3/lib/util.c +++ b/source3/lib/util.c @@ -642,7 +642,7 @@ void msleep(int t) FD_ZERO(&fds); errno = 0; - sys_select_intr(0,&fds,&tval); + sys_select_intr(0,&fds,NULL,NULL,&tval); GetTimeOfDay(&t2); tdiff = TvalDiff(&t1,&t2); diff --git a/source3/lib/util_sock.c b/source3/lib/util_sock.c index 3d32d77000..daab7933da 100644 --- a/source3/lib/util_sock.c +++ b/source3/lib/util_sock.c @@ -208,7 +208,7 @@ int read_data_outstanding(int fd, unsigned int time_out) timeout.tv_sec = (time_t) (time_out / 1000); timeout.tv_usec = (long)(1000 * (time_out % 1000)); - selrtn = sys_select_intr(fd + 1, &fds, &timeout); + selrtn = sys_select_intr(fd + 1, &fds, NULL, NULL, &timeout); if (selrtn <= 0) { @@ -283,7 +283,7 @@ static ssize_t read_socket_with_timeout(int fd,char *buf,size_t mincnt,size_t ma FD_ZERO(&fds); FD_SET(fd,&fds); - selrtn = sys_select_intr(fd+1,&fds,&timeout); + selrtn = sys_select_intr(fd+1,&fds,NULL,NULL,&timeout); /* Check if error */ if (selrtn == -1) { -- cgit