]> pilppa.org Git - linux-2.6-omap-h63xx.git/blobdiff - arch/um/os-Linux/sigio.c
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/shaggy...
[linux-2.6-omap-h63xx.git] / arch / um / os-Linux / sigio.c
index 3fc43b33db667d370ceabf7e63794b43ab0df441..abf47a7c4abd795c039f4c98136163819adb92a4 100644 (file)
@@ -1,32 +1,33 @@
 /*
- * Copyright (C) 2002 Jeff Dike (jdike@karaya.com)
+ * Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
  * Licensed under the GPL
  */
 
 #include <unistd.h>
-#include <stdlib.h>
-#include <termios.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <poll.h>
 #include <pty.h>
+#include <sched.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_constants.h"
 #include "kern_util.h"
-#include "user_util.h"
-#include "sigio.h"
+#include "init.h"
 #include "os.h"
+#include "sigio.h"
 #include "um_malloc.h"
+#include "user.h"
 
-/* Protected by sigio_lock(), also used by sigio_cleanup, which is an
+/*
+ * Protected by sigio_lock(), also used by sigio_cleanup, which is an
  * exitcall.
  */
 static int write_sigio_pid = -1;
+static unsigned long write_sigio_stack;
 
-/* These arrays are initialized before the sigio thread is started, and
+/*
+ * 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.
  */
@@ -41,7 +42,8 @@ struct pollfds {
        int used;
 };
 
-/* Protected by sigio_lock().  Used by the sigio thread, but the UML thread
+/*
+ * Protected by sigio_lock().  Used by the sigio thread, but the UML thread
  * synchronizes with it.
  */
 static struct pollfds current_poll;
@@ -55,24 +57,28 @@ static int write_sigio_thread(void *unused)
        int i, n, respond_fd;
        char c;
 
-        signal(SIGWINCH, SIG_IGN);
+       signal(SIGWINCH, SIG_IGN);
        fds = &current_poll;
-       while(1){
+       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);
+               if (n < 0) {
+                       if (errno == EINTR)
+                               continue;
+                       printk(UM_KERN_ERR "write_sigio_thread : poll returned "
+                              "%d, errno = %d\n", n, errno);
                }
-               for(i = 0; i < fds->used; i++){
+               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 : "
+                       if (p->revents == 0)
+                               continue;
+                       if (p->fd == sigio_private[1]) {
+                               CATCH_EINTR(n = read(sigio_private[1], &c,
+                                                    sizeof(c)));
+                               if (n != sizeof(c))
+                                       printk(UM_KERN_ERR
+                                              "write_sigio_thread : "
                                               "read on socket failed, "
-                                              "err = %d\n", -n);
+                                              "err = %d\n", errno);
                                tmp = current_poll;
                                current_poll = next_poll;
                                next_poll = tmp;
@@ -85,10 +91,11 @@ static int write_sigio_thread(void *unused)
                                        (fds->used - i) * sizeof(*fds->poll));
                        }
 
-                       n = os_write_file(respond_fd, &c, sizeof(c));
-                       if(n != sizeof(c))
-                               printk("write_sigio_thread : write on socket "
-                                      "failed, err = %d\n", -n);
+                       CATCH_EINTR(n = write(respond_fd, &c, sizeof(c)));
+                       if (n != sizeof(c))
+                               printk(UM_KERN_ERR "write_sigio_thread : "
+                                      "write on socket failed, err = %d\n",
+                                      errno);
                }
        }
 
@@ -99,12 +106,13 @@ static int need_poll(struct pollfds *polls, int n)
 {
        struct pollfd *new;
 
-       if(n <= polls->size)
+       if (n <= polls->size)
                return 0;
 
-       new = um_kmalloc_atomic(n * sizeof(struct pollfd));
-       if(new == NULL){
-               printk("need_poll : failed to allocate new pollfds\n");
+       new = kmalloc(n * sizeof(struct pollfd), UM_GFP_ATOMIC);
+       if (new == NULL) {
+               printk(UM_KERN_ERR "need_poll : failed to allocate new "
+                      "pollfds\n");
                return -ENOMEM;
        }
 
@@ -116,7 +124,8 @@ static int need_poll(struct pollfds *polls, int n)
        return 0;
 }
 
-/* Must be called with sigio_lock held, because it's needed by the marked
+/*
+ * Must be called with sigio_lock held, because it's needed by the marked
  * critical section.
  */
 static void update_thread(void)
@@ -126,15 +135,17 @@ static void update_thread(void)
        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);
+       CATCH_EINTR(n = write(sigio_private[0], &c, sizeof(c)));
+       if (n != sizeof(c)) {
+               printk(UM_KERN_ERR "update_thread : write failed, err = %d\n",
+                      errno);
                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);
+       CATCH_EINTR(n = read(sigio_private[0], &c, sizeof(c)));
+       if (n != sizeof(c)) {
+               printk(UM_KERN_ERR "update_thread : read failed, err = %d\n",
+                      errno);
                goto fail;
        }
 
@@ -142,8 +153,10 @@ static void update_thread(void)
        return;
  fail:
        /* Critical section start */
-       if(write_sigio_pid != -1)
+       if (write_sigio_pid != -1) {
                os_kill_process(write_sigio_pid, 1);
+               free_stack(write_sigio_stack, 0);
+       }
        write_sigio_pid = -1;
        close(sigio_private[0]);
        close(sigio_private[1]);
@@ -159,23 +172,23 @@ int add_sigio_fd(int fd)
        int err = 0, i, n;
 
        sigio_lock();
-       for(i = 0; i < all_sigio_fds.used; i++){
-               if(all_sigio_fds.poll[i].fd == fd)
+       for (i = 0; i < all_sigio_fds.used; i++) {
+               if (all_sigio_fds.poll[i].fd == fd)
                        break;
        }
-       if(i == all_sigio_fds.used)
+       if (i == all_sigio_fds.used)
                goto out;
 
        p = &all_sigio_fds.poll[i];
 
-       for(i = 0; i < current_poll.used; i++){
-               if(current_poll.poll[i].fd == fd)
+       for (i = 0; i < current_poll.used; i++) {
+               if (current_poll.poll[i].fd == fd)
                        goto out;
        }
 
        n = current_poll.used;
        err = need_poll(&next_poll, n + 1);
-       if(err)
+       if (err)
                goto out;
 
        memcpy(next_poll.poll, current_poll.poll,
@@ -193,27 +206,29 @@ int ignore_sigio_fd(int fd)
        struct pollfd *p;
        int err = 0, i, n = 0;
 
-       /* This is called from exitcalls elsewhere in UML - if
+       /*
+        * This is called from exitcalls elsewhere in UML - if
         * sigio_cleanup has already run, then update_thread will hang
         * or fail because the thread is no longer running.
         */
-       if(write_sigio_pid == -1)
+       if (write_sigio_pid == -1)
                return -EIO;
 
        sigio_lock();
-       for(i = 0; i < current_poll.used; i++){
-               if(current_poll.poll[i].fd == fd) break;
+       for (i = 0; i < current_poll.used; i++) {
+               if (current_poll.poll[i].fd == fd)
+                       break;
        }
-       if(i == current_poll.used)
+       if (i == current_poll.used)
                goto out;
 
        err = need_poll(&next_poll, current_poll.used - 1);
-       if(err)
+       if (err)
                goto out;
 
-       for(i = 0; i < current_poll.used; i++){
+       for (i = 0; i < current_poll.used; i++) {
                p = &current_poll.poll[i];
-               if(p->fd != fd)
+               if (p->fd != fd)
                        next_poll.poll[n++] = *p;
        }
        next_poll.used = current_poll.used - 1;
@@ -228,9 +243,10 @@ static struct pollfd *setup_initial_poll(int fd)
 {
        struct pollfd *p;
 
-       p = um_kmalloc(sizeof(struct pollfd));
+       p = kmalloc(sizeof(struct pollfd), UM_GFP_KERNEL);
        if (p == NULL) {
-               printk("setup_initial_poll : failed to allocate poll\n");
+               printk(UM_KERN_ERR "setup_initial_poll : failed to allocate "
+                      "poll\n");
                return NULL;
        }
        *p = ((struct pollfd) { .fd             = fd,
@@ -241,7 +257,6 @@ static struct pollfd *setup_initial_poll(int fd)
 
 static void write_sigio_workaround(void)
 {
-       unsigned long stack;
        struct pollfd *p;
        int err;
        int l_write_sigio_fds[2];
@@ -257,27 +272,29 @@ static void write_sigio_workaround(void)
                return;
 
        err = os_pipe(l_write_sigio_fds, 1, 1);
-       if(err < 0){
-               printk("write_sigio_workaround - os_pipe 1 failed, "
+       if (err < 0) {
+               printk(UM_KERN_ERR "write_sigio_workaround - os_pipe 1 failed, "
                       "err = %d\n", -err);
                return;
        }
        err = os_pipe(l_sigio_private, 1, 1);
-       if(err < 0){
-               printk("write_sigio_workaround - os_pipe 2 failed, "
+       if (err < 0) {
+               printk(UM_KERN_ERR "write_sigio_workaround - os_pipe 2 failed, "
                       "err = %d\n", -err);
                goto out_close1;
        }
 
        p = setup_initial_poll(l_sigio_private[1]);
-       if(!p)
+       if (!p)
                goto out_close2;
 
        sigio_lock();
 
-       /* Did we race? Don't try to optimize this, please, it's not so likely
-        * to happen, and no more than once at the boot. */
-       if(write_sigio_pid != -1)
+       /*
+        * Did we race? Don't try to optimize this, please, it's not so likely
+        * to happen, and no more than once at the boot.
+        */
+       if (write_sigio_pid != -1)
                goto out_free;
 
        current_poll = ((struct pollfds) { .poll        = p,
@@ -291,7 +308,8 @@ static void write_sigio_workaround(void)
        memcpy(sigio_private, l_sigio_private, sizeof(l_sigio_private));
 
        write_sigio_pid = run_helper_thread(write_sigio_thread, NULL,
-                                           CLONE_FILES | CLONE_VM, &stack, 0);
+                                           CLONE_FILES | CLONE_VM,
+                                           &write_sigio_stack);
 
        if (write_sigio_pid < 0)
                goto out_clear;
@@ -320,23 +338,27 @@ out_close1:
        close(l_write_sigio_fds[1]);
 }
 
+/* Changed during early boot */
+static int pty_output_sigio = 0;
+static int pty_close_sigio = 0;
+
 void maybe_sigio_broken(int fd, int read)
 {
        int err;
 
-       if(!isatty(fd))
+       if (!isatty(fd))
                return;
 
-       if((read || pty_output_sigio) && (!read || pty_close_sigio))
+       if ((read || pty_output_sigio) && (!read || pty_close_sigio))
                return;
 
        write_sigio_workaround();
 
        sigio_lock();
        err = need_poll(&all_sigio_fds, all_sigio_fds.used + 1);
-       if(err){
-               printk("maybe_sigio_broken - failed to add pollfd for "
-                      "descriptor %d\n", fd);
+       if (err) {
+               printk(UM_KERN_ERR "maybe_sigio_broken - failed to add pollfd "
+                      "for descriptor %d\n", fd);
                goto out;
        }
 
@@ -350,10 +372,171 @@ out:
 
 static void sigio_cleanup(void)
 {
-       if(write_sigio_pid != -1){
-               os_kill_process(write_sigio_pid, 1);
-               write_sigio_pid = -1;
-       }
+       if (write_sigio_pid == -1)
+               return;
+
+       os_kill_process(write_sigio_pid, 1);
+       free_stack(write_sigio_stack, 0);
+       write_sigio_pid = -1;
 }
 
 __uml_exitcall(sigio_cleanup);
+
+/* Used as a flag during SIGIO testing early in boot */
+static volatile int got_sigio = 0;
+
+static 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;
+}
+
+static int async_pty(int master, int slave)
+{
+       int flags;
+
+       flags = fcntl(master, F_GETFL);
+       if (flags < 0)
+               return -errno;
+
+       if ((fcntl(master, F_SETFL, flags | O_NONBLOCK | O_ASYNC) < 0) ||
+           (fcntl(master, F_SETOWN, os_getpid()) < 0))
+               return -errno;
+
+       if ((fcntl(slave, F_SETFL, flags | O_NONBLOCK) < 0))
+               return -errno;
+
+       return 0;
+}
+
+static 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(UM_KERN_ERR "check_one_sigio failed, errno = %d\n",
+                      -pty.err);
+               return;
+       }
+
+       master = pty.master;
+       slave = pty.slave;
+
+       if ((master == -1) || (slave == -1)) {
+               printk(UM_KERN_ERR "check_one_sigio failed to allocate a "
+                      "pty\n");
+               return;
+       }
+
+       /* Not now, but complain so we now where we failed. */
+       err = raw(master);
+       if (err < 0) {
+               printk(UM_KERN_ERR "check_one_sigio : raw failed, errno = %d\n",
+                     -err);
+               return;
+       }
+
+       err = async_pty(master, slave);
+       if (err < 0) {
+               printk(UM_KERN_ERR "check_one_sigio : sigio_async failed, "
+                      "err = %d\n", -err);
+               return;
+       }
+
+       if (sigaction(SIGIO, NULL, &old) < 0) {
+               printk(UM_KERN_ERR "check_one_sigio : sigaction 1 failed, "
+                      "errno = %d\n", errno);
+               return;
+       }
+
+       new = old;
+       new.sa_handler = handler;
+       if (sigaction(SIGIO, &new, NULL) < 0) {
+               printk(UM_KERN_ERR "check_one_sigio : sigaction 2 failed, "
+                      "errno = %d\n", errno);
+               return;
+       }
+
+       got_sigio = 0;
+       (*proc)(master, slave);
+
+       close(master);
+       close(slave);
+
+       if (sigaction(SIGIO, &old, NULL) < 0)
+               printk(UM_KERN_ERR "check_one_sigio : sigaction 3 failed, "
+                      "errno = %d\n", errno);
+}
+
+static void tty_output(int master, int slave)
+{
+       int n;
+       char buf[512];
+
+       printk(UM_KERN_INFO "Checking that host ptys support output SIGIO...");
+
+       memset(buf, 0, sizeof(buf));
+
+       while (write(master, buf, sizeof(buf)) > 0) ;
+       if (errno != EAGAIN)
+               printk(UM_KERN_ERR "tty_output : write failed, errno = %d\n",
+                      errno);
+       while (((n = read(slave, buf, sizeof(buf))) > 0) && !got_sigio)
+               ;
+
+       if (got_sigio) {
+               printk(UM_KERN_CONT "Yes\n");
+               pty_output_sigio = 1;
+       } else if (n == -EAGAIN)
+               printk(UM_KERN_CONT "No, enabling workaround\n");
+       else
+               printk(UM_KERN_CONT "tty_output : read failed, err = %d\n", n);
+}
+
+static void tty_close(int master, int slave)
+{
+       printk(UM_KERN_INFO "Checking that host ptys support SIGIO on "
+              "close...");
+
+       close(slave);
+       if (got_sigio) {
+               printk(UM_KERN_CONT "Yes\n");
+               pty_close_sigio = 1;
+       } else
+               printk(UM_KERN_CONT "No, enabling workaround\n");
+}
+
+void __init check_sigio(void)
+{
+       if ((access("/dev/ptmx", R_OK) < 0) &&
+           (access("/dev/ptyp0", R_OK) < 0)) {
+               printk(UM_KERN_WARNING "No pseudo-terminals available - "
+                      "skipping pty SIGIO check\n");
+               return;
+       }
+       check_one_sigio(tty_output);
+       check_one_sigio(tty_close);
+}
+
+/* Here because it only does the SIGIO testing for now */
+void __init os_check_bugs(void)
+{
+       check_sigio();
+}