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-rw-r--r--fs/file.c130
-rw-r--r--include/linux/fdtable.h1
-rw-r--r--kernel/fork.c130
3 files changed, 131 insertions, 130 deletions
diff --git a/fs/file.c b/fs/file.c
index 754cd05..7dbadaa 100644
--- a/fs/file.c
+++ b/fs/file.c
@@ -261,6 +261,136 @@ int expand_files(struct files_struct *files, int nr)
return expand_fdtable(files, nr);
}
+static int count_open_files(struct fdtable *fdt)
+{
+ int size = fdt->max_fds;
+ int i;
+
+ /* Find the last open fd */
+ for (i = size/(8*sizeof(long)); i > 0; ) {
+ if (fdt->open_fds->fds_bits[--i])
+ break;
+ }
+ i = (i+1) * 8 * sizeof(long);
+ return i;
+}
+
+static struct files_struct *alloc_files(void)
+{
+ struct files_struct *newf;
+ struct fdtable *fdt;
+
+ newf = kmem_cache_alloc(files_cachep, GFP_KERNEL);
+ if (!newf)
+ goto out;
+
+ atomic_set(&newf->count, 1);
+
+ spin_lock_init(&newf->file_lock);
+ newf->next_fd = 0;
+ fdt = &newf->fdtab;
+ fdt->max_fds = NR_OPEN_DEFAULT;
+ fdt->close_on_exec = (fd_set *)&newf->close_on_exec_init;
+ fdt->open_fds = (fd_set *)&newf->open_fds_init;
+ fdt->fd = &newf->fd_array[0];
+ INIT_RCU_HEAD(&fdt->rcu);
+ fdt->next = NULL;
+ rcu_assign_pointer(newf->fdt, fdt);
+out:
+ return newf;
+}
+
+/*
+ * Allocate a new files structure and copy contents from the
+ * passed in files structure.
+ * errorp will be valid only when the returned files_struct is NULL.
+ */
+struct files_struct *dup_fd(struct files_struct *oldf, int *errorp)
+{
+ struct files_struct *newf;
+ struct file **old_fds, **new_fds;
+ int open_files, size, i;
+ struct fdtable *old_fdt, *new_fdt;
+
+ *errorp = -ENOMEM;
+ newf = alloc_files();
+ if (!newf)
+ goto out;
+
+ spin_lock(&oldf->file_lock);
+ old_fdt = files_fdtable(oldf);
+ new_fdt = files_fdtable(newf);
+ open_files = count_open_files(old_fdt);
+
+ /*
+ * 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) {
+ new_fdt->max_fds = 0;
+ spin_unlock(&oldf->file_lock);
+ spin_lock(&newf->file_lock);
+ *errorp = expand_files(newf, open_files-1);
+ spin_unlock(&newf->file_lock);
+ if (*errorp < 0)
+ goto out_release;
+ new_fdt = files_fdtable(newf);
+ /*
+ * Reacquire the oldf lock and a pointer to its fd table
+ * who knows it may have a new bigger fd table. We need
+ * the latest pointer.
+ */
+ spin_lock(&oldf->file_lock);
+ old_fdt = files_fdtable(oldf);
+ }
+
+ old_fds = old_fdt->fd;
+ new_fds = new_fdt->fd;
+
+ memcpy(new_fdt->open_fds->fds_bits,
+ old_fdt->open_fds->fds_bits, open_files/8);
+ memcpy(new_fdt->close_on_exec->fds_bits,
+ old_fdt->close_on_exec->fds_bits, open_files/8);
+
+ for (i = open_files; i != 0; i--) {
+ struct file *f = *old_fds++;
+ if (f) {
+ get_file(f);
+ } else {
+ /*
+ * The fd may be claimed in the fd bitmap but not yet
+ * instantiated in the files array if a sibling thread
+ * is partway through open(). So make sure that this
+ * fd is available to the new process.
+ */
+ FD_CLR(open_files - i, new_fdt->open_fds);
+ }
+ rcu_assign_pointer(*new_fds++, f);
+ }
+ spin_unlock(&oldf->file_lock);
+
+ /* compute the remainder to be cleared */
+ size = (new_fdt->max_fds - open_files) * sizeof(struct file *);
+
+ /* This is long word aligned thus could use a optimized version */
+ memset(new_fds, 0, size);
+
+ if (new_fdt->max_fds > open_files) {
+ int left = (new_fdt->max_fds-open_files)/8;
+ int start = open_files / (8 * sizeof(unsigned long));
+
+ memset(&new_fdt->open_fds->fds_bits[start], 0, left);
+ memset(&new_fdt->close_on_exec->fds_bits[start], 0, left);
+ }
+
+ return newf;
+
+out_release:
+ kmem_cache_free(files_cachep, newf);
+out:
+ return NULL;
+}
+
static void __devinit fdtable_defer_list_init(int cpu)
{
struct fdtable_defer *fddef = &per_cpu(fdtable_defer_list, cpu);
diff --git a/include/linux/fdtable.h b/include/linux/fdtable.h
index a118f3c..4aab6f1 100644
--- a/include/linux/fdtable.h
+++ b/include/linux/fdtable.h
@@ -93,6 +93,7 @@ struct files_struct *get_files_struct(struct task_struct *);
void put_files_struct(struct files_struct *fs);
void reset_files_struct(struct files_struct *);
int unshare_files(struct files_struct **);
+struct files_struct *dup_fd(struct files_struct *, int *);
extern struct kmem_cache *files_cachep;
diff --git a/kernel/fork.c b/kernel/fork.c
index 933e60e..19908b2 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -660,136 +660,6 @@ static int copy_fs(unsigned long clone_flags, struct task_struct *tsk)
return 0;
}
-static int count_open_files(struct fdtable *fdt)
-{
- int size = fdt->max_fds;
- int i;
-
- /* Find the last open fd */
- for (i = size/(8*sizeof(long)); i > 0; ) {
- if (fdt->open_fds->fds_bits[--i])
- break;
- }
- i = (i+1) * 8 * sizeof(long);
- return i;
-}
-
-static struct files_struct *alloc_files(void)
-{
- struct files_struct *newf;
- struct fdtable *fdt;
-
- newf = kmem_cache_alloc(files_cachep, GFP_KERNEL);
- if (!newf)
- goto out;
-
- atomic_set(&newf->count, 1);
-
- spin_lock_init(&newf->file_lock);
- newf->next_fd = 0;
- fdt = &newf->fdtab;
- fdt->max_fds = NR_OPEN_DEFAULT;
- fdt->close_on_exec = (fd_set *)&newf->close_on_exec_init;
- fdt->open_fds = (fd_set *)&newf->open_fds_init;
- fdt->fd = &newf->fd_array[0];
- INIT_RCU_HEAD(&fdt->rcu);
- fdt->next = NULL;
- rcu_assign_pointer(newf->fdt, fdt);
-out:
- return newf;
-}
-
-/*
- * Allocate a new files structure and copy contents from the
- * passed in files structure.
- * errorp will be valid only when the returned files_struct is NULL.
- */
-static struct files_struct *dup_fd(struct files_struct *oldf, int *errorp)
-{
- struct files_struct *newf;
- struct file **old_fds, **new_fds;
- int open_files, size, i;
- struct fdtable *old_fdt, *new_fdt;
-
- *errorp = -ENOMEM;
- newf = alloc_files();
- if (!newf)
- goto out;
-
- spin_lock(&oldf->file_lock);
- old_fdt = files_fdtable(oldf);
- new_fdt = files_fdtable(newf);
- open_files = count_open_files(old_fdt);
-
- /*
- * 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) {
- new_fdt->max_fds = 0;
- spin_unlock(&oldf->file_lock);
- spin_lock(&newf->file_lock);
- *errorp = expand_files(newf, open_files-1);
- spin_unlock(&newf->file_lock);
- if (*errorp < 0)
- goto out_release;
- new_fdt = files_fdtable(newf);
- /*
- * Reacquire the oldf lock and a pointer to its fd table
- * who knows it may have a new bigger fd table. We need
- * the latest pointer.
- */
- spin_lock(&oldf->file_lock);
- old_fdt = files_fdtable(oldf);
- }
-
- old_fds = old_fdt->fd;
- new_fds = new_fdt->fd;
-
- memcpy(new_fdt->open_fds->fds_bits,
- old_fdt->open_fds->fds_bits, open_files/8);
- memcpy(new_fdt->close_on_exec->fds_bits,
- old_fdt->close_on_exec->fds_bits, open_files/8);
-
- for (i = open_files; i != 0; i--) {
- struct file *f = *old_fds++;
- if (f) {
- get_file(f);
- } else {
- /*
- * The fd may be claimed in the fd bitmap but not yet
- * instantiated in the files array if a sibling thread
- * is partway through open(). So make sure that this
- * fd is available to the new process.
- */
- FD_CLR(open_files - i, new_fdt->open_fds);
- }
- rcu_assign_pointer(*new_fds++, f);
- }
- spin_unlock(&oldf->file_lock);
-
- /* compute the remainder to be cleared */
- size = (new_fdt->max_fds - open_files) * sizeof(struct file *);
-
- /* This is long word aligned thus could use a optimized version */
- memset(new_fds, 0, size);
-
- if (new_fdt->max_fds > open_files) {
- int left = (new_fdt->max_fds-open_files)/8;
- int start = open_files / (8 * sizeof(unsigned long));
-
- memset(&new_fdt->open_fds->fds_bits[start], 0, left);
- memset(&new_fdt->close_on_exec->fds_bits[start], 0, left);
- }
-
- return newf;
-
-out_release:
- kmem_cache_free(files_cachep, newf);
-out:
- return NULL;
-}
-
static int copy_files(unsigned long clone_flags, struct task_struct * tsk)
{
struct files_struct *oldf, *newf;