diff options
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/util/select.c | 78 | ||||
| -rw-r--r-- | lib/util/select.h | 3 |
2 files changed, 81 insertions, 0 deletions
diff --git a/lib/util/select.c b/lib/util/select.c index 61df649526..b40538c473 100644 --- a/lib/util/select.c +++ b/lib/util/select.c @@ -208,3 +208,81 @@ int sys_select_intr(int maxfd, fd_set *readfds, fd_set *writefds, fd_set *errorf return ret; } + +/* + * 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; +} diff --git a/lib/util/select.h b/lib/util/select.h index 13c85ce0bf..795c8fa454 100644 --- a/lib/util/select.h +++ b/lib/util/select.h @@ -20,10 +20,13 @@ #ifndef _select_h_ #define _select_h_ +#include "system/select.h" + /* The following definitions come from lib/util/select.c */ void sys_select_signal(char c); int sys_select(int maxfd, fd_set *readfds, fd_set *writefds, fd_set *errorfds, struct timeval *tval); int sys_select_intr(int maxfd, fd_set *readfds, fd_set *writefds, fd_set *errorfds, struct timeval *tval); +int sys_poll(struct pollfd *fds, int num_fds, int timeout); #endif |