Commit 1027abe8 authored by Al Viro's avatar Al Viro
Browse files

[PATCH] merge locate_fd() and get_unused_fd()



	New primitive: alloc_fd(start, flags).  get_unused_fd() and
get_unused_fd_flags() become wrappers on top of it.
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent a1bc6eb4
......@@ -49,73 +49,6 @@ static int get_close_on_exec(unsigned int fd)
return res;
}
/*
* locate_fd finds a free file descriptor in the open_fds fdset,
* expanding the fd arrays if necessary. Must be called with the
* file_lock held for write.
*/
static int locate_fd(unsigned int orig_start, int cloexec)
{
struct files_struct *files = current->files;
unsigned int newfd;
unsigned int start;
int error;
struct fdtable *fdt;
spin_lock(&files->file_lock);
repeat:
fdt = files_fdtable(files);
/*
* Someone might have closed fd's in the range
* orig_start..fdt->next_fd
*/
start = orig_start;
if (start < files->next_fd)
start = files->next_fd;
newfd = start;
if (start < fdt->max_fds)
newfd = find_next_zero_bit(fdt->open_fds->fds_bits,
fdt->max_fds, start);
error = expand_files(files, newfd);
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 = newfd + 1;
FD_SET(newfd, fdt->open_fds);
if (cloexec)
FD_SET(newfd, fdt->close_on_exec);
else
FD_CLR(newfd, fdt->close_on_exec);
error = newfd;
out:
spin_unlock(&files->file_lock);
return error;
}
static int dupfd(struct file *file, unsigned int start, int cloexec)
{
int fd = locate_fd(start, cloexec);
if (fd >= 0)
fd_install(fd, file);
else
fput(file);
return fd;
}
asmlinkage long sys_dup3(unsigned int oldfd, unsigned int newfd, int flags)
{
int err = -EBADF;
......@@ -194,10 +127,15 @@ asmlinkage long sys_dup2(unsigned int oldfd, unsigned int newfd)
asmlinkage long sys_dup(unsigned int fildes)
{
int ret = -EBADF;
struct file * file = fget(fildes);
if (file)
ret = dupfd(file, 0, 0);
struct file *file = fget(fildes);
if (file) {
ret = get_unused_fd();
if (ret >= 0)
fd_install(ret, file);
else
fput(file);
}
return ret;
}
......@@ -322,8 +260,11 @@ static long do_fcntl(int fd, unsigned int cmd, unsigned long arg,
case F_DUPFD_CLOEXEC:
if (arg >= current->signal->rlim[RLIMIT_NOFILE].rlim_cur)
break;
get_file(filp);
err = dupfd(filp, arg, cmd == F_DUPFD_CLOEXEC);
err = alloc_fd(arg, cmd == F_DUPFD_CLOEXEC ? O_CLOEXEC : 0);
if (err >= 0) {
get_file(filp);
fd_install(err, filp);
}
break;
case F_GETFD:
err = get_close_on_exec(fd) ? FD_CLOEXEC : 0;
......
......@@ -6,6 +6,7 @@
* 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>
......@@ -432,3 +433,63 @@ 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);
......@@ -963,62 +963,6 @@ struct file *dentry_open(struct dentry *dentry, struct vfsmount *mnt, int flags)
}
EXPORT_SYMBOL(dentry_open);
/*
* Find an empty file descriptor entry, and mark it busy.
*/
int get_unused_fd_flags(int flags)
{
struct files_struct * files = current->files;
int fd, error;
struct fdtable *fdt;
spin_lock(&files->file_lock);
repeat:
fdt = files_fdtable(files);
fd = find_next_zero_bit(fdt->open_fds->fds_bits, fdt->max_fds,
files->next_fd);
/* Do we need to expand the fd array or fd set? */
error = expand_files(files, fd);
if (error < 0)
goto out;
if (error) {
/*
* If we needed to expand the fs array we
* might have blocked - try again.
*/
goto repeat;
}
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);
files->next_fd = fd + 1;
#if 1
/* Sanity check */
if (fdt->fd[fd] != NULL) {
printk(KERN_WARNING "get_unused_fd: slot %d not NULL!\n", fd);
fdt->fd[fd] = NULL;
}
#endif
error = fd;
out:
spin_unlock(&files->file_lock);
return error;
}
int get_unused_fd(void)
{
return get_unused_fd_flags(0);
}
EXPORT_SYMBOL(get_unused_fd);
static void __put_unused_fd(struct files_struct *files, unsigned int fd)
{
struct fdtable *fdt = files_fdtable(files);
......
......@@ -34,8 +34,9 @@ extern struct file *fget(unsigned int fd);
extern struct file *fget_light(unsigned int fd, int *fput_needed);
extern void set_close_on_exec(unsigned int fd, int flag);
extern void put_filp(struct file *);
extern int alloc_fd(unsigned start, unsigned flags);
extern int get_unused_fd(void);
extern int get_unused_fd_flags(int flags);
#define get_unused_fd_flags(flags) alloc_fd(0, (flags))
extern void put_unused_fd(unsigned int fd);
extern void fd_install(unsigned int fd, struct file *file);
......
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