I'm about to send this Linuswards. Architectures which implement TIF_RESTORE_SIGMASK can wire it up.
David, do you have a test app which people can use? Thanks. From: Davide Libenzi <[email protected]> Implement the epoll_pwait system call, that extend the event wait mechanism with the same logic ppoll and pselect do. The definition of epoll_pwait is: int epoll_pwait(int epfd, struct epoll_event *events, int maxevents, int timeout, const sigset_t *sigmask, size_t sigsetsize); The difference between the vanilla epoll_wait and epoll_pwait is that the latter allows the caller to specify a signal mask to be set while waiting for events. Hence epoll_pwait will wait until either one monitored event, or an unmasked signal happen. If sigmask is NULL, the epoll_pwait system call will act exactly like epoll_wait. For the POSIX definition of pselect, information is available here: http://www.opengroup.org/onlinepubs/009695399/functions/select.html Signed-off-by: Davide Libenzi <[email protected]> Cc: David Woodhouse <[EMAIL PROTECTED]> Cc: Andi Kleen <[EMAIL PROTECTED]> Cc: Michael Kerrisk <[EMAIL PROTECTED]> Cc: Ulrich Drepper <[EMAIL PROTECTED]> Cc: Roland McGrath <[EMAIL PROTECTED]> Signed-off-by: Andrew Morton <[EMAIL PROTECTED]> --- arch/i386/kernel/syscall_table.S | 1 fs/eventpoll.c | 55 +++++++++++++++++++++++++++-- include/asm-i386/unistd.h | 3 + include/linux/syscalls.h | 3 + 4 files changed, 58 insertions(+), 4 deletions(-) diff -puN arch/i386/kernel/syscall_table.S~epoll_pwait arch/i386/kernel/syscall_table.S --- a/arch/i386/kernel/syscall_table.S~epoll_pwait +++ a/arch/i386/kernel/syscall_table.S @@ -318,3 +318,4 @@ ENTRY(sys_call_table) .long sys_vmsplice .long sys_move_pages .long sys_getcpu + .long sys_epoll_pwait diff -puN fs/eventpoll.c~epoll_pwait fs/eventpoll.c --- a/fs/eventpoll.c~epoll_pwait +++ a/fs/eventpoll.c @@ -105,6 +105,8 @@ /* Maximum msec timeout value storeable in a long int */ #define EP_MAX_MSTIMEO min(1000ULL * MAX_SCHEDULE_TIMEOUT / HZ, (LONG_MAX - 999ULL) / HZ) +#define EP_MAX_EVENTS (INT_MAX / sizeof(struct epoll_event)) + struct epoll_filefd { struct file *file; @@ -497,7 +499,7 @@ void eventpoll_release_file(struct file */ asmlinkage long sys_epoll_create(int size) { - int error, fd; + int error, fd = -1; struct eventpoll *ep; struct inode *inode; struct file *file; @@ -640,7 +642,6 @@ eexit_1: return error; } -#define MAX_EVENTS (INT_MAX / sizeof(struct epoll_event)) /* * Implement the event wait interface for the eventpoll file. It is the kernel @@ -657,7 +658,7 @@ asmlinkage long sys_epoll_wait(int epfd, current, epfd, events, maxevents, timeout)); /* The maximum number of event must be greater than zero */ - if (maxevents <= 0 || maxevents > MAX_EVENTS) + if (maxevents <= 0 || maxevents > EP_MAX_EVENTS) return -EINVAL; /* Verify that the area passed by the user is writeable */ @@ -699,6 +700,54 @@ eexit_1: } +#ifdef TIF_RESTORE_SIGMASK + +/* + * Implement the event wait interface for the eventpoll file. It is the kernel + * part of the user space epoll_pwait(2). + */ +asmlinkage long sys_epoll_pwait(int epfd, struct epoll_event __user *events, + int maxevents, int timeout, const sigset_t __user *sigmask, + size_t sigsetsize) +{ + int error; + sigset_t ksigmask, sigsaved; + + /* + * If the caller wants a certain signal mask to be set during the wait, + * we apply it here. + */ + if (sigmask) { + if (sigsetsize != sizeof(sigset_t)) + return -EINVAL; + if (copy_from_user(&ksigmask, sigmask, sizeof(ksigmask))) + return -EFAULT; + sigdelsetmask(&ksigmask, sigmask(SIGKILL) | sigmask(SIGSTOP)); + sigprocmask(SIG_SETMASK, &ksigmask, &sigsaved); + } + + error = sys_epoll_wait(epfd, events, maxevents, timeout); + + /* + * If we changed the signal mask, we need to restore the original one. + * In case we've got a signal while waiting, we do not restore the signal + * mask yet, and we allow do_signal() to deliver the signal on the way back + * to userspace, before the signal mask is restored. + */ + if (sigmask) { + if (error == -EINTR) { + memcpy(¤t->saved_sigmask, &sigsaved, sizeof(sigsaved)); + set_thread_flag(TIF_RESTORE_SIGMASK); + } else + sigprocmask(SIG_SETMASK, &sigsaved, NULL); + } + + return error; +} + +#endif /* #ifdef TIF_RESTORE_SIGMASK */ + + /* * Creates the file descriptor to be used by the epoll interface. */ diff -puN include/asm-i386/unistd.h~epoll_pwait include/asm-i386/unistd.h --- a/include/asm-i386/unistd.h~epoll_pwait +++ a/include/asm-i386/unistd.h @@ -324,10 +324,11 @@ #define __NR_vmsplice 316 #define __NR_move_pages 317 #define __NR_getcpu 318 +#define __NR_epoll_pwait 319 #ifdef __KERNEL__ -#define NR_syscalls 319 +#define NR_syscalls 320 #include <linux/err.h> /* diff -puN include/linux/syscalls.h~epoll_pwait include/linux/syscalls.h --- a/include/linux/syscalls.h~epoll_pwait +++ a/include/linux/syscalls.h @@ -431,6 +431,9 @@ asmlinkage long sys_epoll_ctl(int epfd, struct epoll_event __user *event); asmlinkage long sys_epoll_wait(int epfd, struct epoll_event __user *events, int maxevents, int timeout); +asmlinkage long sys_epoll_pwait(int epfd, struct epoll_event __user *events, + int maxevents, int timeout, const sigset_t __user *sigmask, + size_t sigsetsize); asmlinkage long sys_gethostname(char __user *name, int len); asmlinkage long sys_sethostname(char __user *name, int len); asmlinkage long sys_setdomainname(char __user *name, int len); _ - To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
