diff options
Diffstat (limited to 'arch/um/kernel/sigio_user.c')
| -rw-r--r-- | arch/um/kernel/sigio_user.c | 431 |
1 files changed, 431 insertions, 0 deletions
diff --git a/arch/um/kernel/sigio_user.c b/arch/um/kernel/sigio_user.c new file mode 100644 index 000000000000..668df13d8c9d --- /dev/null +++ b/arch/um/kernel/sigio_user.c @@ -0,0 +1,431 @@ +/* + * Copyright (C) 2002 Jeff Dike (jdike@karaya.com) + * Licensed under the GPL + */ + +#include <unistd.h> +#include <stdlib.h> +#include <termios.h> +#include <pty.h> +#include <signal.h> +#include <errno.h> +#include <string.h> +#include <sched.h> +#include <sys/socket.h> +#include <sys/poll.h> +#include "init.h" +#include "user.h" +#include "kern_util.h" +#include "user_util.h" +#include "sigio.h" +#include "helper.h" +#include "os.h" + +/* Changed during early boot */ +int pty_output_sigio = 0; +int pty_close_sigio = 0; + +/* Used as a flag during SIGIO testing early in boot */ +static volatile int got_sigio = 0; + +void __init handler(int sig) +{ + got_sigio = 1; +} + +struct openpty_arg { + int master; + int slave; + int err; +}; + +static void openpty_cb(void *arg) +{ + struct openpty_arg *info = arg; + + info->err = 0; + if(openpty(&info->master, &info->slave, NULL, NULL, NULL)) + info->err = -errno; +} + +void __init check_one_sigio(void (*proc)(int, int)) +{ + struct sigaction old, new; + struct openpty_arg pty = { .master = -1, .slave = -1 }; + int master, slave, err; + + initial_thread_cb(openpty_cb, &pty); + if(pty.err){ + printk("openpty failed, errno = %d\n", -pty.err); + return; + } + + master = pty.master; + slave = pty.slave; + + if((master == -1) || (slave == -1)){ + printk("openpty failed to allocate a pty\n"); + return; + } + + /* Not now, but complain so we now where we failed. */ + err = raw(master); + if (err < 0) + panic("check_sigio : __raw failed, errno = %d\n", -err); + + err = os_sigio_async(master, slave); + if(err < 0) + panic("tty_fds : sigio_async failed, err = %d\n", -err); + + if(sigaction(SIGIO, NULL, &old) < 0) + panic("check_sigio : sigaction 1 failed, errno = %d\n", errno); + new = old; + new.sa_handler = handler; + if(sigaction(SIGIO, &new, NULL) < 0) + panic("check_sigio : sigaction 2 failed, errno = %d\n", errno); + + got_sigio = 0; + (*proc)(master, slave); + + os_close_file(master); + os_close_file(slave); + + if(sigaction(SIGIO, &old, NULL) < 0) + panic("check_sigio : sigaction 3 failed, errno = %d\n", errno); +} + +static void tty_output(int master, int slave) +{ + int n; + char buf[512]; + + printk("Checking that host ptys support output SIGIO..."); + + memset(buf, 0, sizeof(buf)); + + while(os_write_file(master, buf, sizeof(buf)) > 0) ; + if(errno != EAGAIN) + panic("check_sigio : write failed, errno = %d\n", errno); + while(((n = os_read_file(slave, buf, sizeof(buf))) > 0) && !got_sigio) ; + + if (got_sigio) { + printk("Yes\n"); + pty_output_sigio = 1; + } else if (n == -EAGAIN) { + printk("No, enabling workaround\n"); + } else { + panic("check_sigio : read failed, err = %d\n", n); + } +} + +static void tty_close(int master, int slave) +{ + printk("Checking that host ptys support SIGIO on close..."); + + os_close_file(slave); + if(got_sigio){ + printk("Yes\n"); + pty_close_sigio = 1; + } + else printk("No, enabling workaround\n"); +} + +void __init check_sigio(void) +{ + if((os_access("/dev/ptmx", OS_ACC_R_OK) < 0) && + (os_access("/dev/ptyp0", OS_ACC_R_OK) < 0)){ + printk("No pseudo-terminals available - skipping pty SIGIO " + "check\n"); + return; + } + check_one_sigio(tty_output); + check_one_sigio(tty_close); +} + +/* Protected by sigio_lock(), also used by sigio_cleanup, which is an + * exitcall. + */ +static int write_sigio_pid = -1; + +/* These arrays are initialized before the sigio thread is started, and + * the descriptors closed after it is killed. So, it can't see them change. + * On the UML side, they are changed under the sigio_lock. + */ +static int write_sigio_fds[2] = { -1, -1 }; +static int sigio_private[2] = { -1, -1 }; + +struct pollfds { + struct pollfd *poll; + int size; + int used; +}; + +/* Protected by sigio_lock(). Used by the sigio thread, but the UML thread + * synchronizes with it. + */ +struct pollfds current_poll = { + .poll = NULL, + .size = 0, + .used = 0 +}; + +struct pollfds next_poll = { + .poll = NULL, + .size = 0, + .used = 0 +}; + +static int write_sigio_thread(void *unused) +{ + struct pollfds *fds, tmp; + struct pollfd *p; + int i, n, respond_fd; + char c; + + fds = ¤t_poll; + while(1){ + n = poll(fds->poll, fds->used, -1); + if(n < 0){ + if(errno == EINTR) continue; + printk("write_sigio_thread : poll returned %d, " + "errno = %d\n", n, errno); + } + for(i = 0; i < fds->used; i++){ + p = &fds->poll[i]; + if(p->revents == 0) continue; + if(p->fd == sigio_private[1]){ + n = os_read_file(sigio_private[1], &c, sizeof(c)); + if(n != sizeof(c)) + printk("write_sigio_thread : " + "read failed, err = %d\n", -n); + tmp = current_poll; + current_poll = next_poll; + next_poll = tmp; + respond_fd = sigio_private[1]; + } + else { + respond_fd = write_sigio_fds[1]; + fds->used--; + memmove(&fds->poll[i], &fds->poll[i + 1], + (fds->used - i) * sizeof(*fds->poll)); + } + + n = os_write_file(respond_fd, &c, sizeof(c)); + if(n != sizeof(c)) + printk("write_sigio_thread : write failed, " + "err = %d\n", -n); + } + } +} + +static int need_poll(int n) +{ + if(n <= next_poll.size){ + next_poll.used = n; + return(0); + } + if(next_poll.poll != NULL) kfree(next_poll.poll); + next_poll.poll = um_kmalloc_atomic(n * sizeof(struct pollfd)); + if(next_poll.poll == NULL){ + printk("need_poll : failed to allocate new pollfds\n"); + next_poll.size = 0; + next_poll.used = 0; + return(-1); + } + next_poll.size = n; + next_poll.used = n; + return(0); +} + +/* Must be called with sigio_lock held, because it's needed by the marked + * critical section. */ +static void update_thread(void) +{ + unsigned long flags; + int n; + char c; + + flags = set_signals(0); + n = os_write_file(sigio_private[0], &c, sizeof(c)); + if(n != sizeof(c)){ + printk("update_thread : write failed, err = %d\n", -n); + goto fail; + } + + n = os_read_file(sigio_private[0], &c, sizeof(c)); + if(n != sizeof(c)){ + printk("update_thread : read failed, err = %d\n", -n); + goto fail; + } + + set_signals(flags); + return; + fail: + /* Critical section start */ + if(write_sigio_pid != -1) + os_kill_process(write_sigio_pid, 1); + write_sigio_pid = -1; + os_close_file(sigio_private[0]); + os_close_file(sigio_private[1]); + os_close_file(write_sigio_fds[0]); + os_close_file(write_sigio_fds[1]); + /* Critical section end */ + set_signals(flags); +} + +int add_sigio_fd(int fd, int read) +{ + int err = 0, i, n, events; + + sigio_lock(); + for(i = 0; i < current_poll.used; i++){ + if(current_poll.poll[i].fd == fd) + goto out; + } + + n = current_poll.used + 1; + err = need_poll(n); + if(err) + goto out; + + for(i = 0; i < current_poll.used; i++) + next_poll.poll[i] = current_poll.poll[i]; + + if(read) events = POLLIN; + else events = POLLOUT; + + next_poll.poll[n - 1] = ((struct pollfd) { .fd = fd, + .events = events, + .revents = 0 }); + update_thread(); + out: + sigio_unlock(); + return(err); +} + +int ignore_sigio_fd(int fd) +{ + struct pollfd *p; + int err = 0, i, n = 0; + + sigio_lock(); + for(i = 0; i < current_poll.used; i++){ + if(current_poll.poll[i].fd == fd) break; + } + if(i == current_poll.used) + goto out; + + err = need_poll(current_poll.used - 1); + if(err) + goto out; + + for(i = 0; i < current_poll.used; i++){ + p = ¤t_poll.poll[i]; + if(p->fd != fd) next_poll.poll[n++] = current_poll.poll[i]; + } + if(n == i){ + printk("ignore_sigio_fd : fd %d not found\n", fd); + err = -1; + goto out; + } + + update_thread(); + out: + sigio_unlock(); + return(err); +} + +static int setup_initial_poll(int fd) +{ + struct pollfd *p; + + p = um_kmalloc(sizeof(struct pollfd)); + if(p == NULL){ + printk("setup_initial_poll : failed to allocate poll\n"); + return(-1); + } + *p = ((struct pollfd) { .fd = fd, + .events = POLLIN, + .revents = 0 }); + current_poll = ((struct pollfds) { .poll = p, + .used = 1, + .size = 1 }); + return(0); +} + +void write_sigio_workaround(void) +{ + unsigned long stack; + int err; + + sigio_lock(); + if(write_sigio_pid != -1) + goto out; + + err = os_pipe(write_sigio_fds, 1, 1); + if(err < 0){ + printk("write_sigio_workaround - os_pipe 1 failed, " + "err = %d\n", -err); + goto out; + } + err = os_pipe(sigio_private, 1, 1); + if(err < 0){ + printk("write_sigio_workaround - os_pipe 2 failed, " + "err = %d\n", -err); + goto out_close1; + } + if(setup_initial_poll(sigio_private[1])) + goto out_close2; + + write_sigio_pid = run_helper_thread(write_sigio_thread, NULL, + CLONE_FILES | CLONE_VM, &stack, 0); + + if(write_sigio_pid < 0) goto out_close2; + + if(write_sigio_irq(write_sigio_fds[0])) + goto out_kill; + + out: + sigio_unlock(); + return; + + out_kill: + os_kill_process(write_sigio_pid, 1); + write_sigio_pid = -1; + out_close2: + os_close_file(sigio_private[0]); + os_close_file(sigio_private[1]); + out_close1: + os_close_file(write_sigio_fds[0]); + os_close_file(write_sigio_fds[1]); + sigio_unlock(); +} + +int read_sigio_fd(int fd) +{ + int n; + char c; + + n = os_read_file(fd, &c, sizeof(c)); + if(n != sizeof(c)){ + if(n < 0) { + printk("read_sigio_fd - read failed, err = %d\n", -n); + return(n); + } + else { + printk("read_sigio_fd - short read, bytes = %d\n", n); + return(-EIO); + } + } + return(n); +} + +static void sigio_cleanup(void) +{ + if (write_sigio_pid != -1) { + os_kill_process(write_sigio_pid, 1); + write_sigio_pid = -1; + } +} + +__uml_exitcall(sigio_cleanup); |