1 files changed, 601 insertions, 0 deletions

diff --git a/fs/fcntl.c b/fs/fcntl.c
new file mode 100644
index 000000000000..c1708066bf55
--- /dev/null
+++ b/fs/fcntl.c
@@ -0,0 +1,601 @@
+/*
+ *  linux/fs/fcntl.c
+ *
+ *  Copyright (C) 1991, 1992  Linus Torvalds
+ */
+
+#include <linux/syscalls.h>
+#include <linux/init.h>
+#include <linux/mm.h>
+#include <linux/fs.h>
+#include <linux/file.h>
+#include <linux/dnotify.h>
+#include <linux/smp_lock.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/security.h>
+#include <linux/ptrace.h>
+
+#include <asm/poll.h>
+#include <asm/siginfo.h>
+#include <asm/uaccess.h>
+
+void fastcall set_close_on_exec(unsigned int fd, int flag)
+{
+        struct files_struct *files = current->files;
+        spin_lock(&files->file_lock);
+        if (flag)
+                FD_SET(fd, files->close_on_exec);
+        else
+                FD_CLR(fd, files->close_on_exec);
+        spin_unlock(&files->file_lock);
+}
+
+static inline int get_close_on_exec(unsigned int fd)
+{
+        struct files_struct *files = current->files;
+        int res;
+        spin_lock(&files->file_lock);
+        res = FD_ISSET(fd, files->close_on_exec);
+        spin_unlock(&files->file_lock);
+        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(struct files_struct *files, 
+                            struct file *file, unsigned int orig_start)
+{
+        unsigned int newfd;
+        unsigned int start;
+        int error;
+
+        error = -EINVAL;
+        if (orig_start >= current->signal->rlim[RLIMIT_NOFILE].rlim_cur)
+                goto out;
+
+repeat:
+        /*
+         * Someone might have closed fd's in the range
+         * orig_start..files->next_fd
+         */
+        start = orig_start;
+        if (start < files->next_fd)
+                start = files->next_fd;
+
+        newfd = start;
+        if (start < files->max_fdset) {
+                newfd = find_next_zero_bit(files->open_fds->fds_bits,
+                        files->max_fdset, start);
+        }
+        
+        error = -EMFILE;
+        if (newfd >= current->signal->rlim[RLIMIT_NOFILE].rlim_cur)
+                goto out;
+
+        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;
+        
+        error = newfd;
+        
+out:
+        return error;
+}
+
+static int dupfd(struct file *file, unsigned int start)
+{
+        struct files_struct * files = current->files;
+        int fd;
+
+        spin_lock(&files->file_lock);
+        fd = locate_fd(files, file, start);
+        if (fd >= 0) {
+                FD_SET(fd, files->open_fds);
+                FD_CLR(fd, files->close_on_exec);
+                spin_unlock(&files->file_lock);
+                fd_install(fd, file);
+        } else {
+                spin_unlock(&files->file_lock);
+                fput(file);
+        }
+
+        return fd;
+}
+
+asmlinkage long sys_dup2(unsigned int oldfd, unsigned int newfd)
+{
+        int err = -EBADF;
+        struct file * file, *tofree;
+        struct files_struct * files = current->files;
+
+        spin_lock(&files->file_lock);
+        if (!(file = fcheck(oldfd)))
+                goto out_unlock;
+        err = newfd;
+        if (newfd == oldfd)
+                goto out_unlock;
+        err = -EBADF;
+        if (newfd >= current->signal->rlim[RLIMIT_NOFILE].rlim_cur)
+                goto out_unlock;
+        get_file(file);                 /* We are now finished with oldfd */
+
+        err = expand_files(files, newfd);
+        if (err < 0)
+                goto out_fput;
+
+        /* To avoid races with open() and dup(), we will mark the fd as
+         * in-use in the open-file bitmap throughout the entire dup2()
+         * process.  This is quite safe: do_close() uses the fd array
+         * entry, not the bitmap, to decide what work needs to be
+         * done.  --sct */
+        /* Doesn't work. open() might be there first. --AV */
+
+        /* Yes. It's a race. In user space. Nothing sane to do */
+        err = -EBUSY;
+        tofree = files->fd[newfd];
+        if (!tofree && FD_ISSET(newfd, files->open_fds))
+                goto out_fput;
+
+        files->fd[newfd] = file;
+        FD_SET(newfd, files->open_fds);
+        FD_CLR(newfd, files->close_on_exec);
+        spin_unlock(&files->file_lock);
+
+        if (tofree)
+                filp_close(tofree, files);
+        err = newfd;
+out:
+        return err;
+out_unlock:
+        spin_unlock(&files->file_lock);
+        goto out;
+
+out_fput:
+        spin_unlock(&files->file_lock);
+        fput(file);
+        goto out;
+}
+
+asmlinkage long sys_dup(unsigned int fildes)
+{
+        int ret = -EBADF;
+        struct file * file = fget(fildes);
+
+        if (file)
+                ret = dupfd(file, 0);
+        return ret;
+}
+
+#define SETFL_MASK (O_APPEND | O_NONBLOCK | O_NDELAY | FASYNC | O_DIRECT | O_NOATIME)
+
+static int setfl(int fd, struct file * filp, unsigned long arg)
+{
+        struct inode * inode = filp->f_dentry->d_inode;
+        int error = 0;
+
+        /* O_APPEND cannot be cleared if the file is marked as append-only */
+        if (!(arg & O_APPEND) && IS_APPEND(inode))
+                return -EPERM;
+
+        /* O_NOATIME can only be set by the owner or superuser */
+        if ((arg & O_NOATIME) && !(filp->f_flags & O_NOATIME))
+                if (current->fsuid != inode->i_uid && !capable(CAP_FOWNER))
+                        return -EPERM;
+
+        /* required for strict SunOS emulation */
+        if (O_NONBLOCK != O_NDELAY)
+               if (arg & O_NDELAY)
+                   arg |= O_NONBLOCK;
+
+        if (arg & O_DIRECT) {
+                if (!filp->f_mapping || !filp->f_mapping->a_ops ||
+                        !filp->f_mapping->a_ops->direct_IO)
+                                return -EINVAL;
+        }
+
+        if (filp->f_op && filp->f_op->check_flags)
+                error = filp->f_op->check_flags(arg);
+        if (error)
+                return error;
+
+        lock_kernel();
+        if ((arg ^ filp->f_flags) & FASYNC) {
+                if (filp->f_op && filp->f_op->fasync) {
+                        error = filp->f_op->fasync(fd, filp, (arg & FASYNC) != 0);
+                        if (error < 0)
+                                goto out;
+                }
+        }
+
+        filp->f_flags = (arg & SETFL_MASK) | (filp->f_flags & ~SETFL_MASK);
+ out:
+        unlock_kernel();
+        return error;
+}
+
+static void f_modown(struct file *filp, unsigned long pid,
+                     uid_t uid, uid_t euid, int force)
+{
+        write_lock_irq(&filp->f_owner.lock);
+        if (force || !filp->f_owner.pid) {
+                filp->f_owner.pid = pid;
+                filp->f_owner.uid = uid;
+                filp->f_owner.euid = euid;
+        }
+        write_unlock_irq(&filp->f_owner.lock);
+}
+
+int f_setown(struct file *filp, unsigned long arg, int force)
+{
+        int err;
+        
+        err = security_file_set_fowner(filp);
+        if (err)
+                return err;
+
+        f_modown(filp, arg, current->uid, current->euid, force);
+        return 0;
+}
+
+EXPORT_SYMBOL(f_setown);
+
+void f_delown(struct file *filp)
+{
+        f_modown(filp, 0, 0, 0, 1);
+}
+
+static long do_fcntl(int fd, unsigned int cmd, unsigned long arg,
+                struct file *filp)
+{
+        long err = -EINVAL;
+
+        switch (cmd) {
+        case F_DUPFD:
+                get_file(filp);
+                err = dupfd(filp, arg);
+                break;
+        case F_GETFD:
+                err = get_close_on_exec(fd) ? FD_CLOEXEC : 0;
+                break;
+        case F_SETFD:
+                err = 0;
+                set_close_on_exec(fd, arg & FD_CLOEXEC);
+                break;
+        case F_GETFL:
+                err = filp->f_flags;
+                break;
+        case F_SETFL:
+                err = setfl(fd, filp, arg);
+                break;
+        case F_GETLK:
+                err = fcntl_getlk(filp, (struct flock __user *) arg);
+                break;
+        case F_SETLK:
+        case F_SETLKW:
+                err = fcntl_setlk(filp, cmd, (struct flock __user *) arg);
+                break;
+        case F_GETOWN:
+                /*
+                 * XXX If f_owner is a process group, the
+                 * negative return value will get converted
+                 * into an error.  Oops.  If we keep the
+                 * current syscall conventions, the only way
+                 * to fix this will be in libc.
+                 */
+                err = filp->f_owner.pid;
+                force_successful_syscall_return();
+                break;
+        case F_SETOWN:
+                err = f_setown(filp, arg, 1);
+                break;
+        case F_GETSIG:
+                err = filp->f_owner.signum;
+                break;
+        case F_SETSIG:
+                /* arg == 0 restores default behaviour. */
+                if (arg < 0 || arg > _NSIG) {
+                        break;
+                }
+                err = 0;
+                filp->f_owner.signum = arg;
+                break;
+        case F_GETLEASE:
+                err = fcntl_getlease(filp);
+                break;
+        case F_SETLEASE:
+                err = fcntl_setlease(fd, filp, arg);
+                break;
+        case F_NOTIFY:
+                err = fcntl_dirnotify(fd, filp, arg);
+                break;
+        default:
+                break;
+        }
+        return err;
+}
+
+asmlinkage long sys_fcntl(unsigned int fd, unsigned int cmd, unsigned long arg)
+{       
+        struct file *filp;
+        long err = -EBADF;
+
+        filp = fget(fd);
+        if (!filp)
+                goto out;
+
+        err = security_file_fcntl(filp, cmd, arg);
+        if (err) {
+                fput(filp);
+                return err;
+        }
+
+        err = do_fcntl(fd, cmd, arg, filp);
+
+        fput(filp);
+out:
+        return err;
+}
+
+#if BITS_PER_LONG == 32
+asmlinkage long sys_fcntl64(unsigned int fd, unsigned int cmd, unsigned long arg)
+{       
+        struct file * filp;
+        long err;
+
+        err = -EBADF;
+        filp = fget(fd);
+        if (!filp)
+                goto out;
+
+        err = security_file_fcntl(filp, cmd, arg);
+        if (err) {
+                fput(filp);
+                return err;
+        }
+        err = -EBADF;
+        
+        switch (cmd) {
+                case F_GETLK64:
+                        err = fcntl_getlk64(filp, (struct flock64 __user *) arg);
+                        break;
+                case F_SETLK64:
+                case F_SETLKW64:
+                        err = fcntl_setlk64(filp, cmd, (struct flock64 __user *) arg);
+                        break;
+                default:
+                        err = do_fcntl(fd, cmd, arg, filp);
+                        break;
+        }
+        fput(filp);
+out:
+        return err;
+}
+#endif
+
+/* Table to convert sigio signal codes into poll band bitmaps */
+
+static long band_table[NSIGPOLL] = {
+        POLLIN | POLLRDNORM,                    /* POLL_IN */
+        POLLOUT | POLLWRNORM | POLLWRBAND,      /* POLL_OUT */
+        POLLIN | POLLRDNORM | POLLMSG,          /* POLL_MSG */
+        POLLERR,                                /* POLL_ERR */
+        POLLPRI | POLLRDBAND,                   /* POLL_PRI */
+        POLLHUP | POLLERR                       /* POLL_HUP */
+};
+
+static inline int sigio_perm(struct task_struct *p,
+                             struct fown_struct *fown, int sig)
+{
+        return (((fown->euid == 0) ||
+                 (fown->euid == p->suid) || (fown->euid == p->uid) ||
+                 (fown->uid == p->suid) || (fown->uid == p->uid)) &&
+                !security_file_send_sigiotask(p, fown, sig));
+}
+
+static void send_sigio_to_task(struct task_struct *p,
+                               struct fown_struct *fown, 
+                               int fd,
+                               int reason)
+{
+        if (!sigio_perm(p, fown, fown->signum))
+                return;
+
+        switch (fown->signum) {
+                siginfo_t si;
+                default:
+                        /* Queue a rt signal with the appropriate fd as its
+                           value.  We use SI_SIGIO as the source, not 
+                           SI_KERNEL, since kernel signals always get 
+                           delivered even if we can't queue.  Failure to
+                           queue in this case _should_ be reported; we fall
+                           back to SIGIO in that case. --sct */
+                        si.si_signo = fown->signum;
+                        si.si_errno = 0;
+                        si.si_code  = reason;
+                        /* Make sure we are called with one of the POLL_*
+                           reasons, otherwise we could leak kernel stack into
+                           userspace.  */
+                        if ((reason & __SI_MASK) != __SI_POLL)
+                                BUG();
+                        if (reason - POLL_IN >= NSIGPOLL)
+                                si.si_band  = ~0L;
+                        else
+                                si.si_band = band_table[reason - POLL_IN];
+                        si.si_fd    = fd;
+                        if (!send_sig_info(fown->signum, &si, p))
+                                break;
+                /* fall-through: fall back on the old plain SIGIO signal */
+                case 0:
+                        send_group_sig_info(SIGIO, SEND_SIG_PRIV, p);
+        }
+}
+
+void send_sigio(struct fown_struct *fown, int fd, int band)
+{
+        struct task_struct *p;
+        int pid;
+        
+        read_lock(&fown->lock);
+        pid = fown->pid;
+        if (!pid)
+                goto out_unlock_fown;
+        
+        read_lock(&tasklist_lock);
+        if (pid > 0) {
+                p = find_task_by_pid(pid);
+                if (p) {
+                        send_sigio_to_task(p, fown, fd, band);
+                }
+        } else {
+                do_each_task_pid(-pid, PIDTYPE_PGID, p) {
+                        send_sigio_to_task(p, fown, fd, band);
+                } while_each_task_pid(-pid, PIDTYPE_PGID, p);
+        }
+        read_unlock(&tasklist_lock);
+ out_unlock_fown:
+        read_unlock(&fown->lock);
+}
+
+static void send_sigurg_to_task(struct task_struct *p,
+                                struct fown_struct *fown)
+{
+        if (sigio_perm(p, fown, SIGURG))
+                send_group_sig_info(SIGURG, SEND_SIG_PRIV, p);
+}
+
+int send_sigurg(struct fown_struct *fown)
+{
+        struct task_struct *p;
+        int pid, ret = 0;
+        
+        read_lock(&fown->lock);
+        pid = fown->pid;
+        if (!pid)
+                goto out_unlock_fown;
+
+        ret = 1;
+        
+        read_lock(&tasklist_lock);
+        if (pid > 0) {
+                p = find_task_by_pid(pid);
+                if (p) {
+                        send_sigurg_to_task(p, fown);
+                }
+        } else {
+                do_each_task_pid(-pid, PIDTYPE_PGID, p) {
+                        send_sigurg_to_task(p, fown);
+                } while_each_task_pid(-pid, PIDTYPE_PGID, p);
+        }
+        read_unlock(&tasklist_lock);
+ out_unlock_fown:
+        read_unlock(&fown->lock);
+        return ret;
+}
+
+static DEFINE_RWLOCK(fasync_lock);
+static kmem_cache_t *fasync_cache;
+
+/*
+ * fasync_helper() is used by some character device drivers (mainly mice)
+ * to set up the fasync queue. It returns negative on error, 0 if it did
+ * no changes and positive if it added/deleted the entry.
+ */
+int fasync_helper(int fd, struct file * filp, int on, struct fasync_struct **fapp)
+{
+        struct fasync_struct *fa, **fp;
+        struct fasync_struct *new = NULL;
+        int result = 0;
+
+        if (on) {
+                new = kmem_cache_alloc(fasync_cache, SLAB_KERNEL);
+                if (!new)
+                        return -ENOMEM;
+        }
+        write_lock_irq(&fasync_lock);
+        for (fp = fapp; (fa = *fp) != NULL; fp = &fa->fa_next) {
+                if (fa->fa_file == filp) {
+                        if(on) {
+                                fa->fa_fd = fd;
+                                kmem_cache_free(fasync_cache, new);
+                        } else {
+                                *fp = fa->fa_next;
+                                kmem_cache_free(fasync_cache, fa);
+                                result = 1;
+                        }
+                        goto out;
+                }
+        }
+
+        if (on) {
+                new->magic = FASYNC_MAGIC;
+                new->fa_file = filp;
+                new->fa_fd = fd;
+                new->fa_next = *fapp;
+                *fapp = new;
+                result = 1;
+        }
+out:
+        write_unlock_irq(&fasync_lock);
+        return result;
+}
+
+EXPORT_SYMBOL(fasync_helper);
+
+void __kill_fasync(struct fasync_struct *fa, int sig, int band)
+{
+        while (fa) {
+                struct fown_struct * fown;
+                if (fa->magic != FASYNC_MAGIC) {
+                        printk(KERN_ERR "kill_fasync: bad magic number in "
+                               "fasync_struct!\n");
+                        return;
+                }
+                fown = &fa->fa_file->f_owner;
+                /* Don't send SIGURG to processes which have not set a
+                   queued signum: SIGURG has its own default signalling
+                   mechanism. */
+                if (!(sig == SIGURG && fown->signum == 0))
+                        send_sigio(fown, fa->fa_fd, band);
+                fa = fa->fa_next;
+        }
+}
+
+EXPORT_SYMBOL(__kill_fasync);
+
+void kill_fasync(struct fasync_struct **fp, int sig, int band)
+{
+        /* First a quick test without locking: usually
+         * the list is empty.
+         */
+        if (*fp) {
+                read_lock(&fasync_lock);
+                /* reread *fp after obtaining the lock */
+                __kill_fasync(*fp, sig, band);
+                read_unlock(&fasync_lock);
+        }
+}
+EXPORT_SYMBOL(kill_fasync);
+
+static int __init fasync_init(void)
+{
+        fasync_cache = kmem_cache_create("fasync_cache",
+                sizeof(struct fasync_struct), 0, SLAB_PANIC, NULL, NULL);
+        return 0;
+}
+
+module_init(fasync_init)