X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=fs%2Ffile.c;h=87e129030ab1564a69061b82b9608c59cced9f1a;hb=9329d1beaeed1a94f030c784dcec5ff973f402c4;hp=689d2b6947e3e2da5dabf76d7e8512186b4eec40;hpb=afbec7fff4928c273a1f1bb14dfdfdf62688a193;p=safe%2Fjmp%2Flinux-2.6

diff --git a/fs/file.c b/fs/file.c
index 689d2b6..87e1290 100644
--- a/fs/file.c
+++ b/fs/file.c
@@ -6,9 +6,11 @@
  *  Manage the dynamic fd arrays in the process files_struct.
  */
 
+#include <linux/module.h>
 #include <linux/fs.h>
 #include <linux/mm.h>
 #include <linux/time.h>
+#include <linux/sched.h>
 #include <linux/slab.h>
 #include <linux/vmalloc.h>
 #include <linux/file.h>
@@ -26,6 +28,8 @@ struct fdtable_defer {
 };
 
 int sysctl_nr_open __read_mostly = 1024*1024;
+int sysctl_nr_open_min = BITS_PER_LONG;
+int sysctl_nr_open_max = 1024 * 1024; /* raised later */
 
 /*
  * We use this list to defer free fdtables that have vmalloced
@@ -248,9 +252,18 @@ int expand_files(struct files_struct *files, int nr)
 	struct fdtable *fdt;
 
 	fdt = files_fdtable(files);
+
+	/*
+	 * N.B. For clone tasks sharing a files structure, this test
+	 * will limit the total number of files that can be opened.
+	 */
+	if (nr >= current->signal->rlim[RLIMIT_NOFILE].rlim_cur)
+		return -EMFILE;
+
 	/* Do we need to expand? */
 	if (nr < fdt->max_fds)
 		return 0;
+
 	/* Can we expand? */
 	if (nr >= sysctl_nr_open)
 		return -EMFILE;
@@ -308,11 +321,16 @@ struct files_struct *dup_fd(struct files_struct *oldf, int *errorp)
 
 	/*
 	 * Check whether we need to allocate a larger fd array and fd set.
-	 * Note: we're not a clone task, so the open count won't change.
 	 */
-	if (open_files > new_fdt->max_fds) {
+	while (unlikely(open_files > new_fdt->max_fds)) {
 		spin_unlock(&oldf->file_lock);
 
+		if (new_fdt != &newf->fdtab) {
+			free_fdarr(new_fdt);
+			free_fdset(new_fdt);
+			kfree(new_fdt);
+		}
+
 		new_fdt = alloc_fdtable(open_files - 1);
 		if (!new_fdt) {
 			*errorp = -ENOMEM;
@@ -335,6 +353,7 @@ struct files_struct *dup_fd(struct files_struct *oldf, int *errorp)
 		 */
 		spin_lock(&oldf->file_lock);
 		old_fdt = files_fdtable(oldf);
+		open_files = count_open_files(old_fdt);
 	}
 
 	old_fds = old_fdt->fd;
@@ -399,6 +418,8 @@ void __init files_defer_init(void)
 	int i;
 	for_each_possible_cpu(i)
 		fdtable_defer_list_init(i);
+	sysctl_nr_open_max = min((size_t)INT_MAX, ~(size_t)0/sizeof(void *)) &
+			     -BITS_PER_LONG;
 }
 
 struct files_struct init_files = {
@@ -413,3 +434,63 @@ struct files_struct init_files = {
 	},
 	.file_lock	= __SPIN_LOCK_UNLOCKED(init_task.file_lock),
 };
+
+/*
+ * allocate a file descriptor, mark it busy.
+ */
+int alloc_fd(unsigned start, unsigned flags)
+{
+	struct files_struct *files = current->files;
+	unsigned int fd;
+	int error;
+	struct fdtable *fdt;
+
+	spin_lock(&files->file_lock);
+repeat:
+	fdt = files_fdtable(files);
+	fd = start;
+	if (fd < files->next_fd)
+		fd = files->next_fd;
+
+	if (fd < fdt->max_fds)
+		fd = find_next_zero_bit(fdt->open_fds->fds_bits,
+					   fdt->max_fds, fd);
+
+	error = expand_files(files, fd);
+	if (error < 0)
+		goto out;
+
+	/*
+	 * If we needed to expand the fs array we
+	 * might have blocked - try again.
+	 */
+	if (error)
+		goto repeat;
+
+	if (start <= files->next_fd)
+		files->next_fd = fd + 1;
+
+	FD_SET(fd, fdt->open_fds);
+	if (flags & O_CLOEXEC)
+		FD_SET(fd, fdt->close_on_exec);
+	else
+		FD_CLR(fd, fdt->close_on_exec);
+	error = fd;
+#if 1
+	/* Sanity check */
+	if (rcu_dereference(fdt->fd[fd]) != NULL) {
+		printk(KERN_WARNING "alloc_fd: slot %d not NULL!\n", fd);
+		rcu_assign_pointer(fdt->fd[fd], NULL);
+	}
+#endif
+
+out:
+	spin_unlock(&files->file_lock);
+	return error;
+}
+
+int get_unused_fd(void)
+{
+	return alloc_fd(0, 0);
+}
+EXPORT_SYMBOL(get_unused_fd);