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;
+}