Linux-2.6.12-rc2v2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 534 insertions, 0 deletions

diff --git a/fs/select.c b/fs/select.c
new file mode 100644
index 000000000000..25b1ccac2f2c
--- /dev/null
+++ b/fs/select.c
@@ -0,0 +1,534 @@
+/*
+ * This file contains the procedures for the handling of select and poll
+ *
+ * Created for Linux based loosely upon Mathius Lattner's minix
+ * patches by Peter MacDonald. Heavily edited by Linus.
+ *
+ *  4 February 1994
+ *     COFF/ELF binary emulation. If the process has the STICKY_TIMEOUTS
+ *     flag set in its personality we do *not* modify the given timeout
+ *     parameter to reflect time remaining.
+ *
+ *  24 January 2000
+ *     Changed sys_poll()/do_poll() to use PAGE_SIZE chunk-based allocation 
+ *     of fds to overcome nfds < 16390 descriptors limit (Tigran Aivazian).
+ */
+
+#include <linux/syscalls.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/smp_lock.h>
+#include <linux/poll.h>
+#include <linux/personality.h> /* for STICKY_TIMEOUTS */
+#include <linux/file.h>
+#include <linux/fs.h>
+
+#include <asm/uaccess.h>
+
+#define ROUND_UP(x,y) (((x)+(y)-1)/(y))
+#define DEFAULT_POLLMASK (POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM)
+
+struct poll_table_entry {
+        struct file * filp;
+        wait_queue_t wait;
+        wait_queue_head_t * wait_address;
+};
+
+struct poll_table_page {
+        struct poll_table_page * next;
+        struct poll_table_entry * entry;
+        struct poll_table_entry entries[0];
+};
+
+#define POLL_TABLE_FULL(table) \
+        ((unsigned long)((table)->entry+1) > PAGE_SIZE + (unsigned long)(table))
+
+/*
+ * Ok, Peter made a complicated, but straightforward multiple_wait() function.
+ * I have rewritten this, taking some shortcuts: This code may not be easy to
+ * follow, but it should be free of race-conditions, and it's practical. If you
+ * understand what I'm doing here, then you understand how the linux
+ * sleep/wakeup mechanism works.
+ *
+ * Two very simple procedures, poll_wait() and poll_freewait() make all the
+ * work.  poll_wait() is an inline-function defined in <linux/poll.h>,
+ * as all select/poll functions have to call it to add an entry to the
+ * poll table.
+ */
+void __pollwait(struct file *filp, wait_queue_head_t *wait_address, poll_table *p);
+
+void poll_initwait(struct poll_wqueues *pwq)
+{
+        init_poll_funcptr(&pwq->pt, __pollwait);
+        pwq->error = 0;
+        pwq->table = NULL;
+}
+
+EXPORT_SYMBOL(poll_initwait);
+
+void poll_freewait(struct poll_wqueues *pwq)
+{
+        struct poll_table_page * p = pwq->table;
+        while (p) {
+                struct poll_table_entry * entry;
+                struct poll_table_page *old;
+
+                entry = p->entry;
+                do {
+                        entry--;
+                        remove_wait_queue(entry->wait_address,&entry->wait);
+                        fput(entry->filp);
+                } while (entry > p->entries);
+                old = p;
+                p = p->next;
+                free_page((unsigned long) old);
+        }
+}
+
+EXPORT_SYMBOL(poll_freewait);
+
+void __pollwait(struct file *filp, wait_queue_head_t *wait_address, poll_table *_p)
+{
+        struct poll_wqueues *p = container_of(_p, struct poll_wqueues, pt);
+        struct poll_table_page *table = p->table;
+
+        if (!table || POLL_TABLE_FULL(table)) {
+                struct poll_table_page *new_table;
+
+                new_table = (struct poll_table_page *) __get_free_page(GFP_KERNEL);
+                if (!new_table) {
+                        p->error = -ENOMEM;
+                        __set_current_state(TASK_RUNNING);
+                        return;
+                }
+                new_table->entry = new_table->entries;
+                new_table->next = table;
+                p->table = new_table;
+                table = new_table;
+        }
+
+        /* Add a new entry */
+        {
+                struct poll_table_entry * entry = table->entry;
+                table->entry = entry+1;
+                get_file(filp);
+                entry->filp = filp;
+                entry->wait_address = wait_address;
+                init_waitqueue_entry(&entry->wait, current);
+                add_wait_queue(wait_address,&entry->wait);
+        }
+}
+
+#define FDS_IN(fds, n)          (fds->in + n)
+#define FDS_OUT(fds, n)         (fds->out + n)
+#define FDS_EX(fds, n)          (fds->ex + n)
+
+#define BITS(fds, n)    (*FDS_IN(fds, n)|*FDS_OUT(fds, n)|*FDS_EX(fds, n))
+
+static int max_select_fd(unsigned long n, fd_set_bits *fds)
+{
+        unsigned long *open_fds;
+        unsigned long set;
+        int max;
+
+        /* handle last in-complete long-word first */
+        set = ~(~0UL << (n & (__NFDBITS-1)));
+        n /= __NFDBITS;
+        open_fds = current->files->open_fds->fds_bits+n;
+        max = 0;
+        if (set) {
+                set &= BITS(fds, n);
+                if (set) {
+                        if (!(set & ~*open_fds))
+                                goto get_max;
+                        return -EBADF;
+                }
+        }
+        while (n) {
+                open_fds--;
+                n--;
+                set = BITS(fds, n);
+                if (!set)
+                        continue;
+                if (set & ~*open_fds)
+                        return -EBADF;
+                if (max)
+                        continue;
+get_max:
+                do {
+                        max++;
+                        set >>= 1;
+                } while (set);
+                max += n * __NFDBITS;
+        }
+
+        return max;
+}
+
+#define BIT(i)          (1UL << ((i)&(__NFDBITS-1)))
+#define MEM(i,m)        ((m)+(unsigned)(i)/__NFDBITS)
+#define ISSET(i,m)      (((i)&*(m)) != 0)
+#define SET(i,m)        (*(m) |= (i))
+
+#define POLLIN_SET (POLLRDNORM | POLLRDBAND | POLLIN | POLLHUP | POLLERR)
+#define POLLOUT_SET (POLLWRBAND | POLLWRNORM | POLLOUT | POLLERR)
+#define POLLEX_SET (POLLPRI)
+
+int do_select(int n, fd_set_bits *fds, long *timeout)
+{
+        struct poll_wqueues table;
+        poll_table *wait;
+        int retval, i;
+        long __timeout = *timeout;
+
+        spin_lock(&current->files->file_lock);
+        retval = max_select_fd(n, fds);
+        spin_unlock(&current->files->file_lock);
+
+        if (retval < 0)
+                return retval;
+        n = retval;
+
+        poll_initwait(&table);
+        wait = &table.pt;
+        if (!__timeout)
+                wait = NULL;
+        retval = 0;
+        for (;;) {
+                unsigned long *rinp, *routp, *rexp, *inp, *outp, *exp;
+
+                set_current_state(TASK_INTERRUPTIBLE);
+
+                inp = fds->in; outp = fds->out; exp = fds->ex;
+                rinp = fds->res_in; routp = fds->res_out; rexp = fds->res_ex;
+
+                for (i = 0; i < n; ++rinp, ++routp, ++rexp) {
+                        unsigned long in, out, ex, all_bits, bit = 1, mask, j;
+                        unsigned long res_in = 0, res_out = 0, res_ex = 0;
+                        struct file_operations *f_op = NULL;
+                        struct file *file = NULL;
+
+                        in = *inp++; out = *outp++; ex = *exp++;
+                        all_bits = in | out | ex;
+                        if (all_bits == 0) {
+                                i += __NFDBITS;
+                                continue;
+                        }
+
+                        for (j = 0; j < __NFDBITS; ++j, ++i, bit <<= 1) {
+                                if (i >= n)
+                                        break;
+                                if (!(bit & all_bits))
+                                        continue;
+                                file = fget(i);
+                                if (file) {
+                                        f_op = file->f_op;
+                                        mask = DEFAULT_POLLMASK;
+                                        if (f_op && f_op->poll)
+                                                mask = (*f_op->poll)(file, retval ? NULL : wait);
+                                        fput(file);
+                                        if ((mask & POLLIN_SET) && (in & bit)) {
+                                                res_in |= bit;
+                                                retval++;
+                                        }
+                                        if ((mask & POLLOUT_SET) && (out & bit)) {
+                                                res_out |= bit;
+                                                retval++;
+                                        }
+                                        if ((mask & POLLEX_SET) && (ex & bit)) {
+                                                res_ex |= bit;
+                                                retval++;
+                                        }
+                                }
+                                cond_resched();
+                        }
+                        if (res_in)
+                                *rinp = res_in;
+                        if (res_out)
+                                *routp = res_out;
+                        if (res_ex)
+                                *rexp = res_ex;
+                }
+                wait = NULL;
+                if (retval || !__timeout || signal_pending(current))
+                        break;
+                if(table.error) {
+                        retval = table.error;
+                        break;
+                }
+                __timeout = schedule_timeout(__timeout);
+        }
+        __set_current_state(TASK_RUNNING);
+
+        poll_freewait(&table);
+
+        /*
+         * Up-to-date the caller timeout.
+         */
+        *timeout = __timeout;
+        return retval;
+}
+
+static void *select_bits_alloc(int size)
+{
+        return kmalloc(6 * size, GFP_KERNEL);
+}
+
+static void select_bits_free(void *bits, int size)
+{
+        kfree(bits);
+}
+
+/*
+ * We can actually return ERESTARTSYS instead of EINTR, but I'd
+ * like to be certain this leads to no problems. So I return
+ * EINTR just for safety.
+ *
+ * Update: ERESTARTSYS breaks at least the xview clock binary, so
+ * I'm trying ERESTARTNOHAND which restart only when you want to.
+ */
+#define MAX_SELECT_SECONDS \
+        ((unsigned long) (MAX_SCHEDULE_TIMEOUT / HZ)-1)
+
+asmlinkage long
+sys_select(int n, fd_set __user *inp, fd_set __user *outp, fd_set __user *exp, struct timeval __user *tvp)
+{
+        fd_set_bits fds;
+        char *bits;
+        long timeout;
+        int ret, size, max_fdset;
+
+        timeout = MAX_SCHEDULE_TIMEOUT;
+        if (tvp) {
+                time_t sec, usec;
+
+                if (!access_ok(VERIFY_READ, tvp, sizeof(*tvp))
+                    || __get_user(sec, &tvp->tv_sec)
+                    || __get_user(usec, &tvp->tv_usec)) {
+                        ret = -EFAULT;
+                        goto out_nofds;
+                }
+
+                ret = -EINVAL;
+                if (sec < 0 || usec < 0)
+                        goto out_nofds;
+
+                if ((unsigned long) sec < MAX_SELECT_SECONDS) {
+                        timeout = ROUND_UP(usec, 1000000/HZ);
+                        timeout += sec * (unsigned long) HZ;
+                }
+        }
+
+        ret = -EINVAL;
+        if (n < 0)
+                goto out_nofds;
+
+        /* max_fdset can increase, so grab it once to avoid race */
+        max_fdset = current->files->max_fdset;
+        if (n > max_fdset)
+                n = max_fdset;
+
+        /*
+         * We need 6 bitmaps (in/out/ex for both incoming and outgoing),
+         * since we used fdset we need to allocate memory in units of
+         * long-words. 
+         */
+        ret = -ENOMEM;
+        size = FDS_BYTES(n);
+        bits = select_bits_alloc(size);
+        if (!bits)
+                goto out_nofds;
+        fds.in      = (unsigned long *)  bits;
+        fds.out     = (unsigned long *) (bits +   size);
+        fds.ex      = (unsigned long *) (bits + 2*size);
+        fds.res_in  = (unsigned long *) (bits + 3*size);
+        fds.res_out = (unsigned long *) (bits + 4*size);
+        fds.res_ex  = (unsigned long *) (bits + 5*size);
+
+        if ((ret = get_fd_set(n, inp, fds.in)) ||
+            (ret = get_fd_set(n, outp, fds.out)) ||
+            (ret = get_fd_set(n, exp, fds.ex)))
+                goto out;
+        zero_fd_set(n, fds.res_in);
+        zero_fd_set(n, fds.res_out);
+        zero_fd_set(n, fds.res_ex);
+
+        ret = do_select(n, &fds, &timeout);
+
+        if (tvp && !(current->personality & STICKY_TIMEOUTS)) {
+                time_t sec = 0, usec = 0;
+                if (timeout) {
+                        sec = timeout / HZ;
+                        usec = timeout % HZ;
+                        usec *= (1000000/HZ);
+                }
+                put_user(sec, &tvp->tv_sec);
+                put_user(usec, &tvp->tv_usec);
+        }
+
+        if (ret < 0)
+                goto out;
+        if (!ret) {
+                ret = -ERESTARTNOHAND;
+                if (signal_pending(current))
+                        goto out;
+                ret = 0;
+        }
+
+        if (set_fd_set(n, inp, fds.res_in) ||
+            set_fd_set(n, outp, fds.res_out) ||
+            set_fd_set(n, exp, fds.res_ex))
+                ret = -EFAULT;
+
+out:
+        select_bits_free(bits, size);
+out_nofds:
+        return ret;
+}
+
+struct poll_list {
+        struct poll_list *next;
+        int len;
+        struct pollfd entries[0];
+};
+
+#define POLLFD_PER_PAGE  ((PAGE_SIZE-sizeof(struct poll_list)) / sizeof(struct pollfd))
+
+static void do_pollfd(unsigned int num, struct pollfd * fdpage,
+        poll_table ** pwait, int *count)
+{
+        int i;
+
+        for (i = 0; i < num; i++) {
+                int fd;
+                unsigned int mask;
+                struct pollfd *fdp;
+
+                mask = 0;
+                fdp = fdpage+i;
+                fd = fdp->fd;
+                if (fd >= 0) {
+                        struct file * file = fget(fd);
+                        mask = POLLNVAL;
+                        if (file != NULL) {
+                                mask = DEFAULT_POLLMASK;
+                                if (file->f_op && file->f_op->poll)
+                                        mask = file->f_op->poll(file, *pwait);
+                                mask &= fdp->events | POLLERR | POLLHUP;
+                                fput(file);
+                        }
+                        if (mask) {
+                                *pwait = NULL;
+                                (*count)++;
+                        }
+                }
+                fdp->revents = mask;
+        }
+}
+
+static int do_poll(unsigned int nfds,  struct poll_list *list,
+                        struct poll_wqueues *wait, long timeout)
+{
+        int count = 0;
+        poll_table* pt = &wait->pt;
+
+        if (!timeout)
+                pt = NULL;
+ 
+        for (;;) {
+                struct poll_list *walk;
+                set_current_state(TASK_INTERRUPTIBLE);
+                walk = list;
+                while(walk != NULL) {
+                        do_pollfd( walk->len, walk->entries, &pt, &count);
+                        walk = walk->next;
+                }
+                pt = NULL;
+                if (count || !timeout || signal_pending(current))
+                        break;
+                count = wait->error;
+                if (count)
+                        break;
+                timeout = schedule_timeout(timeout);
+        }
+        __set_current_state(TASK_RUNNING);
+        return count;
+}
+
+asmlinkage long sys_poll(struct pollfd __user * ufds, unsigned int nfds, long timeout)
+{
+        struct poll_wqueues table;
+        int fdcount, err;
+        unsigned int i;
+        struct poll_list *head;
+        struct poll_list *walk;
+
+        /* Do a sanity check on nfds ... */
+        if (nfds > current->files->max_fdset && nfds > OPEN_MAX)
+                return -EINVAL;
+
+        if (timeout) {
+                /* Careful about overflow in the intermediate values */
+                if ((unsigned long) timeout < MAX_SCHEDULE_TIMEOUT / HZ)
+                        timeout = (unsigned long)(timeout*HZ+999)/1000+1;
+                else /* Negative or overflow */
+                        timeout = MAX_SCHEDULE_TIMEOUT;
+        }
+
+        poll_initwait(&table);
+
+        head = NULL;
+        walk = NULL;
+        i = nfds;
+        err = -ENOMEM;
+        while(i!=0) {
+                struct poll_list *pp;
+                pp = kmalloc(sizeof(struct poll_list)+
+                                sizeof(struct pollfd)*
+                                (i>POLLFD_PER_PAGE?POLLFD_PER_PAGE:i),
+                                        GFP_KERNEL);
+                if(pp==NULL)
+                        goto out_fds;
+                pp->next=NULL;
+                pp->len = (i>POLLFD_PER_PAGE?POLLFD_PER_PAGE:i);
+                if (head == NULL)
+                        head = pp;
+                else
+                        walk->next = pp;
+
+                walk = pp;
+                if (copy_from_user(pp->entries, ufds + nfds-i, 
+                                sizeof(struct pollfd)*pp->len)) {
+                        err = -EFAULT;
+                        goto out_fds;
+                }
+                i -= pp->len;
+        }
+        fdcount = do_poll(nfds, head, &table, timeout);
+
+        /* OK, now copy the revents fields back to user space. */
+        walk = head;
+        err = -EFAULT;
+        while(walk != NULL) {
+                struct pollfd *fds = walk->entries;
+                int j;
+
+                for (j=0; j < walk->len; j++, ufds++) {
+                        if(__put_user(fds[j].revents, &ufds->revents))
+                                goto out_fds;
+                }
+                walk = walk->next;
+        }
+        err = fdcount;
+        if (!fdcount && signal_pending(current))
+                err = -EINTR;
+out_fds:
+        walk = head;
+        while(walk!=NULL) {
+                struct poll_list *pp = walk->next;
+                kfree(walk);
+                walk = pp;
+        }
+        poll_freewait(&table);
+        return err;
+}