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1056 lines
24 KiB
1056 lines
24 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* linux/fs/fcntl.c |
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* |
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* Copyright (C) 1991, 1992 Linus Torvalds |
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*/ |
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|
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#include <linux/syscalls.h> |
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#include <linux/init.h> |
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#include <linux/mm.h> |
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#include <linux/sched/task.h> |
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#include <linux/fs.h> |
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#include <linux/file.h> |
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#include <linux/fdtable.h> |
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#include <linux/capability.h> |
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#include <linux/dnotify.h> |
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#include <linux/slab.h> |
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#include <linux/module.h> |
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#include <linux/pipe_fs_i.h> |
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#include <linux/security.h> |
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#include <linux/ptrace.h> |
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#include <linux/signal.h> |
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#include <linux/rcupdate.h> |
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#include <linux/pid_namespace.h> |
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#include <linux/user_namespace.h> |
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#include <linux/memfd.h> |
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#include <linux/compat.h> |
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#include <linux/mount.h> |
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#include <linux/poll.h> |
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#include <asm/siginfo.h> |
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#include <linux/uaccess.h> |
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#define SETFL_MASK (O_APPEND | O_NONBLOCK | O_NDELAY | O_DIRECT | O_NOATIME) |
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static int setfl(int fd, struct file * filp, unsigned long arg) |
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{ |
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struct inode * inode = file_inode(filp); |
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int error = 0; |
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|
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/* |
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* O_APPEND cannot be cleared if the file is marked as append-only |
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* and the file is open for write. |
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*/ |
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if (((arg ^ filp->f_flags) & O_APPEND) && IS_APPEND(inode)) |
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return -EPERM; |
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|
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/* O_NOATIME can only be set by the owner or superuser */ |
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if ((arg & O_NOATIME) && !(filp->f_flags & O_NOATIME)) |
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if (!inode_owner_or_capable(file_mnt_user_ns(filp), inode)) |
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return -EPERM; |
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|
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/* required for strict SunOS emulation */ |
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if (O_NONBLOCK != O_NDELAY) |
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if (arg & O_NDELAY) |
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arg |= O_NONBLOCK; |
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|
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/* Pipe packetized mode is controlled by O_DIRECT flag */ |
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if (!S_ISFIFO(inode->i_mode) && (arg & O_DIRECT)) { |
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if (!filp->f_mapping || !filp->f_mapping->a_ops || |
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!filp->f_mapping->a_ops->direct_IO) |
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return -EINVAL; |
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} |
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|
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if (filp->f_op->check_flags) |
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error = filp->f_op->check_flags(arg); |
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if (error) |
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return error; |
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|
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/* |
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* ->fasync() is responsible for setting the FASYNC bit. |
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*/ |
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if (((arg ^ filp->f_flags) & FASYNC) && filp->f_op->fasync) { |
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error = filp->f_op->fasync(fd, filp, (arg & FASYNC) != 0); |
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if (error < 0) |
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goto out; |
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if (error > 0) |
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error = 0; |
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} |
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spin_lock(&filp->f_lock); |
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filp->f_flags = (arg & SETFL_MASK) | (filp->f_flags & ~SETFL_MASK); |
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spin_unlock(&filp->f_lock); |
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out: |
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return error; |
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} |
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static void f_modown(struct file *filp, struct pid *pid, enum pid_type type, |
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int force) |
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{ |
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write_lock_irq(&filp->f_owner.lock); |
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if (force || !filp->f_owner.pid) { |
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put_pid(filp->f_owner.pid); |
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filp->f_owner.pid = get_pid(pid); |
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filp->f_owner.pid_type = type; |
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if (pid) { |
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const struct cred *cred = current_cred(); |
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filp->f_owner.uid = cred->uid; |
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filp->f_owner.euid = cred->euid; |
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} |
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} |
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write_unlock_irq(&filp->f_owner.lock); |
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} |
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void __f_setown(struct file *filp, struct pid *pid, enum pid_type type, |
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int force) |
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{ |
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security_file_set_fowner(filp); |
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f_modown(filp, pid, type, force); |
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} |
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EXPORT_SYMBOL(__f_setown); |
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|
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int f_setown(struct file *filp, unsigned long arg, int force) |
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{ |
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enum pid_type type; |
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struct pid *pid = NULL; |
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int who = arg, ret = 0; |
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|
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type = PIDTYPE_TGID; |
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if (who < 0) { |
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/* avoid overflow below */ |
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if (who == INT_MIN) |
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return -EINVAL; |
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type = PIDTYPE_PGID; |
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who = -who; |
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} |
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rcu_read_lock(); |
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if (who) { |
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pid = find_vpid(who); |
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if (!pid) |
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ret = -ESRCH; |
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} |
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if (!ret) |
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__f_setown(filp, pid, type, force); |
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rcu_read_unlock(); |
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|
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return ret; |
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} |
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EXPORT_SYMBOL(f_setown); |
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|
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void f_delown(struct file *filp) |
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{ |
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f_modown(filp, NULL, PIDTYPE_TGID, 1); |
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} |
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pid_t f_getown(struct file *filp) |
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{ |
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pid_t pid = 0; |
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read_lock(&filp->f_owner.lock); |
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rcu_read_lock(); |
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if (pid_task(filp->f_owner.pid, filp->f_owner.pid_type)) { |
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pid = pid_vnr(filp->f_owner.pid); |
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if (filp->f_owner.pid_type == PIDTYPE_PGID) |
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pid = -pid; |
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} |
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rcu_read_unlock(); |
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read_unlock(&filp->f_owner.lock); |
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return pid; |
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} |
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static int f_setown_ex(struct file *filp, unsigned long arg) |
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{ |
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struct f_owner_ex __user *owner_p = (void __user *)arg; |
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struct f_owner_ex owner; |
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struct pid *pid; |
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int type; |
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int ret; |
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ret = copy_from_user(&owner, owner_p, sizeof(owner)); |
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if (ret) |
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return -EFAULT; |
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|
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switch (owner.type) { |
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case F_OWNER_TID: |
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type = PIDTYPE_PID; |
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break; |
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|
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case F_OWNER_PID: |
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type = PIDTYPE_TGID; |
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break; |
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|
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case F_OWNER_PGRP: |
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type = PIDTYPE_PGID; |
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break; |
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|
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default: |
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return -EINVAL; |
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} |
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rcu_read_lock(); |
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pid = find_vpid(owner.pid); |
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if (owner.pid && !pid) |
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ret = -ESRCH; |
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else |
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__f_setown(filp, pid, type, 1); |
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rcu_read_unlock(); |
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return ret; |
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} |
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static int f_getown_ex(struct file *filp, unsigned long arg) |
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{ |
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struct f_owner_ex __user *owner_p = (void __user *)arg; |
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struct f_owner_ex owner = {}; |
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int ret = 0; |
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read_lock(&filp->f_owner.lock); |
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rcu_read_lock(); |
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if (pid_task(filp->f_owner.pid, filp->f_owner.pid_type)) |
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owner.pid = pid_vnr(filp->f_owner.pid); |
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rcu_read_unlock(); |
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switch (filp->f_owner.pid_type) { |
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case PIDTYPE_PID: |
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owner.type = F_OWNER_TID; |
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break; |
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case PIDTYPE_TGID: |
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owner.type = F_OWNER_PID; |
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break; |
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case PIDTYPE_PGID: |
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owner.type = F_OWNER_PGRP; |
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break; |
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default: |
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WARN_ON(1); |
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ret = -EINVAL; |
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break; |
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} |
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read_unlock(&filp->f_owner.lock); |
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if (!ret) { |
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ret = copy_to_user(owner_p, &owner, sizeof(owner)); |
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if (ret) |
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ret = -EFAULT; |
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} |
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return ret; |
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} |
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#ifdef CONFIG_CHECKPOINT_RESTORE |
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static int f_getowner_uids(struct file *filp, unsigned long arg) |
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{ |
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struct user_namespace *user_ns = current_user_ns(); |
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uid_t __user *dst = (void __user *)arg; |
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uid_t src[2]; |
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int err; |
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read_lock(&filp->f_owner.lock); |
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src[0] = from_kuid(user_ns, filp->f_owner.uid); |
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src[1] = from_kuid(user_ns, filp->f_owner.euid); |
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read_unlock(&filp->f_owner.lock); |
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err = put_user(src[0], &dst[0]); |
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err |= put_user(src[1], &dst[1]); |
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|
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return err; |
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} |
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#else |
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static int f_getowner_uids(struct file *filp, unsigned long arg) |
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{ |
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return -EINVAL; |
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} |
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#endif |
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static bool rw_hint_valid(enum rw_hint hint) |
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{ |
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switch (hint) { |
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case RWH_WRITE_LIFE_NOT_SET: |
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case RWH_WRITE_LIFE_NONE: |
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case RWH_WRITE_LIFE_SHORT: |
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case RWH_WRITE_LIFE_MEDIUM: |
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case RWH_WRITE_LIFE_LONG: |
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case RWH_WRITE_LIFE_EXTREME: |
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return true; |
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default: |
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return false; |
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} |
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} |
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static long fcntl_rw_hint(struct file *file, unsigned int cmd, |
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unsigned long arg) |
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{ |
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struct inode *inode = file_inode(file); |
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u64 __user *argp = (u64 __user *)arg; |
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enum rw_hint hint; |
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u64 h; |
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|
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switch (cmd) { |
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case F_GET_FILE_RW_HINT: |
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h = file_write_hint(file); |
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if (copy_to_user(argp, &h, sizeof(*argp))) |
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return -EFAULT; |
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return 0; |
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case F_SET_FILE_RW_HINT: |
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if (copy_from_user(&h, argp, sizeof(h))) |
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return -EFAULT; |
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hint = (enum rw_hint) h; |
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if (!rw_hint_valid(hint)) |
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return -EINVAL; |
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spin_lock(&file->f_lock); |
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file->f_write_hint = hint; |
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spin_unlock(&file->f_lock); |
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return 0; |
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case F_GET_RW_HINT: |
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h = inode->i_write_hint; |
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if (copy_to_user(argp, &h, sizeof(*argp))) |
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return -EFAULT; |
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return 0; |
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case F_SET_RW_HINT: |
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if (copy_from_user(&h, argp, sizeof(h))) |
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return -EFAULT; |
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hint = (enum rw_hint) h; |
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if (!rw_hint_valid(hint)) |
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return -EINVAL; |
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inode_lock(inode); |
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inode->i_write_hint = hint; |
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inode_unlock(inode); |
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return 0; |
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default: |
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return -EINVAL; |
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} |
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} |
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static long do_fcntl(int fd, unsigned int cmd, unsigned long arg, |
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struct file *filp) |
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{ |
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void __user *argp = (void __user *)arg; |
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struct flock flock; |
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long err = -EINVAL; |
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|
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switch (cmd) { |
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case F_DUPFD: |
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err = f_dupfd(arg, filp, 0); |
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break; |
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case F_DUPFD_CLOEXEC: |
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err = f_dupfd(arg, filp, O_CLOEXEC); |
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break; |
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case F_GETFD: |
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err = get_close_on_exec(fd) ? FD_CLOEXEC : 0; |
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break; |
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case F_SETFD: |
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err = 0; |
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set_close_on_exec(fd, arg & FD_CLOEXEC); |
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break; |
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case F_GETFL: |
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err = filp->f_flags; |
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break; |
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case F_SETFL: |
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err = setfl(fd, filp, arg); |
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break; |
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#if BITS_PER_LONG != 32 |
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/* 32-bit arches must use fcntl64() */ |
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case F_OFD_GETLK: |
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#endif |
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case F_GETLK: |
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if (copy_from_user(&flock, argp, sizeof(flock))) |
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return -EFAULT; |
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err = fcntl_getlk(filp, cmd, &flock); |
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if (!err && copy_to_user(argp, &flock, sizeof(flock))) |
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return -EFAULT; |
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break; |
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#if BITS_PER_LONG != 32 |
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/* 32-bit arches must use fcntl64() */ |
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case F_OFD_SETLK: |
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case F_OFD_SETLKW: |
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#endif |
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fallthrough; |
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case F_SETLK: |
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case F_SETLKW: |
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if (copy_from_user(&flock, argp, sizeof(flock))) |
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return -EFAULT; |
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err = fcntl_setlk(fd, filp, cmd, &flock); |
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break; |
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case F_GETOWN: |
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/* |
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* XXX If f_owner is a process group, the |
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* negative return value will get converted |
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* into an error. Oops. If we keep the |
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* current syscall conventions, the only way |
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* to fix this will be in libc. |
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*/ |
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err = f_getown(filp); |
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force_successful_syscall_return(); |
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break; |
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case F_SETOWN: |
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err = f_setown(filp, arg, 1); |
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break; |
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case F_GETOWN_EX: |
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err = f_getown_ex(filp, arg); |
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break; |
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case F_SETOWN_EX: |
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err = f_setown_ex(filp, arg); |
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break; |
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case F_GETOWNER_UIDS: |
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err = f_getowner_uids(filp, arg); |
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break; |
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case F_GETSIG: |
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err = filp->f_owner.signum; |
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break; |
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case F_SETSIG: |
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/* arg == 0 restores default behaviour. */ |
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if (!valid_signal(arg)) { |
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break; |
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} |
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err = 0; |
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filp->f_owner.signum = arg; |
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break; |
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case F_GETLEASE: |
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err = fcntl_getlease(filp); |
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break; |
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case F_SETLEASE: |
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err = fcntl_setlease(fd, filp, arg); |
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break; |
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case F_NOTIFY: |
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err = fcntl_dirnotify(fd, filp, arg); |
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break; |
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case F_SETPIPE_SZ: |
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case F_GETPIPE_SZ: |
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err = pipe_fcntl(filp, cmd, arg); |
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break; |
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case F_ADD_SEALS: |
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case F_GET_SEALS: |
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err = memfd_fcntl(filp, cmd, arg); |
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break; |
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case F_GET_RW_HINT: |
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case F_SET_RW_HINT: |
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case F_GET_FILE_RW_HINT: |
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case F_SET_FILE_RW_HINT: |
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err = fcntl_rw_hint(filp, cmd, arg); |
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break; |
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default: |
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break; |
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} |
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return err; |
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} |
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|
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static int check_fcntl_cmd(unsigned cmd) |
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{ |
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switch (cmd) { |
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case F_DUPFD: |
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case F_DUPFD_CLOEXEC: |
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case F_GETFD: |
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case F_SETFD: |
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case F_GETFL: |
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return 1; |
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} |
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return 0; |
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} |
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|
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SYSCALL_DEFINE3(fcntl, unsigned int, fd, unsigned int, cmd, unsigned long, arg) |
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{ |
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struct fd f = fdget_raw(fd); |
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long err = -EBADF; |
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|
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if (!f.file) |
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goto out; |
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|
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if (unlikely(f.file->f_mode & FMODE_PATH)) { |
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if (!check_fcntl_cmd(cmd)) |
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goto out1; |
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} |
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|
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err = security_file_fcntl(f.file, cmd, arg); |
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if (!err) |
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err = do_fcntl(fd, cmd, arg, f.file); |
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|
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out1: |
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fdput(f); |
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out: |
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return err; |
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} |
|
|
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#if BITS_PER_LONG == 32 |
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SYSCALL_DEFINE3(fcntl64, unsigned int, fd, unsigned int, cmd, |
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unsigned long, arg) |
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{ |
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void __user *argp = (void __user *)arg; |
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struct fd f = fdget_raw(fd); |
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struct flock64 flock; |
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long err = -EBADF; |
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|
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if (!f.file) |
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goto out; |
|
|
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if (unlikely(f.file->f_mode & FMODE_PATH)) { |
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if (!check_fcntl_cmd(cmd)) |
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goto out1; |
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} |
|
|
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err = security_file_fcntl(f.file, cmd, arg); |
|
if (err) |
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goto out1; |
|
|
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switch (cmd) { |
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case F_GETLK64: |
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case F_OFD_GETLK: |
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err = -EFAULT; |
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if (copy_from_user(&flock, argp, sizeof(flock))) |
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break; |
|
err = fcntl_getlk64(f.file, cmd, &flock); |
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if (!err && copy_to_user(argp, &flock, sizeof(flock))) |
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err = -EFAULT; |
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break; |
|
case F_SETLK64: |
|
case F_SETLKW64: |
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case F_OFD_SETLK: |
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case F_OFD_SETLKW: |
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err = -EFAULT; |
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if (copy_from_user(&flock, argp, sizeof(flock))) |
|
break; |
|
err = fcntl_setlk64(fd, f.file, cmd, &flock); |
|
break; |
|
default: |
|
err = do_fcntl(fd, cmd, arg, f.file); |
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break; |
|
} |
|
out1: |
|
fdput(f); |
|
out: |
|
return err; |
|
} |
|
#endif |
|
|
|
#ifdef CONFIG_COMPAT |
|
/* careful - don't use anywhere else */ |
|
#define copy_flock_fields(dst, src) \ |
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(dst)->l_type = (src)->l_type; \ |
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(dst)->l_whence = (src)->l_whence; \ |
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(dst)->l_start = (src)->l_start; \ |
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(dst)->l_len = (src)->l_len; \ |
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(dst)->l_pid = (src)->l_pid; |
|
|
|
static int get_compat_flock(struct flock *kfl, const struct compat_flock __user *ufl) |
|
{ |
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struct compat_flock fl; |
|
|
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if (copy_from_user(&fl, ufl, sizeof(struct compat_flock))) |
|
return -EFAULT; |
|
copy_flock_fields(kfl, &fl); |
|
return 0; |
|
} |
|
|
|
static int get_compat_flock64(struct flock *kfl, const struct compat_flock64 __user *ufl) |
|
{ |
|
struct compat_flock64 fl; |
|
|
|
if (copy_from_user(&fl, ufl, sizeof(struct compat_flock64))) |
|
return -EFAULT; |
|
copy_flock_fields(kfl, &fl); |
|
return 0; |
|
} |
|
|
|
static int put_compat_flock(const struct flock *kfl, struct compat_flock __user *ufl) |
|
{ |
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struct compat_flock fl; |
|
|
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memset(&fl, 0, sizeof(struct compat_flock)); |
|
copy_flock_fields(&fl, kfl); |
|
if (copy_to_user(ufl, &fl, sizeof(struct compat_flock))) |
|
return -EFAULT; |
|
return 0; |
|
} |
|
|
|
static int put_compat_flock64(const struct flock *kfl, struct compat_flock64 __user *ufl) |
|
{ |
|
struct compat_flock64 fl; |
|
|
|
BUILD_BUG_ON(sizeof(kfl->l_start) > sizeof(ufl->l_start)); |
|
BUILD_BUG_ON(sizeof(kfl->l_len) > sizeof(ufl->l_len)); |
|
|
|
memset(&fl, 0, sizeof(struct compat_flock64)); |
|
copy_flock_fields(&fl, kfl); |
|
if (copy_to_user(ufl, &fl, sizeof(struct compat_flock64))) |
|
return -EFAULT; |
|
return 0; |
|
} |
|
#undef copy_flock_fields |
|
|
|
static unsigned int |
|
convert_fcntl_cmd(unsigned int cmd) |
|
{ |
|
switch (cmd) { |
|
case F_GETLK64: |
|
return F_GETLK; |
|
case F_SETLK64: |
|
return F_SETLK; |
|
case F_SETLKW64: |
|
return F_SETLKW; |
|
} |
|
|
|
return cmd; |
|
} |
|
|
|
/* |
|
* GETLK was successful and we need to return the data, but it needs to fit in |
|
* the compat structure. |
|
* l_start shouldn't be too big, unless the original start + end is greater than |
|
* COMPAT_OFF_T_MAX, in which case the app was asking for trouble, so we return |
|
* -EOVERFLOW in that case. l_len could be too big, in which case we just |
|
* truncate it, and only allow the app to see that part of the conflicting lock |
|
* that might make sense to it anyway |
|
*/ |
|
static int fixup_compat_flock(struct flock *flock) |
|
{ |
|
if (flock->l_start > COMPAT_OFF_T_MAX) |
|
return -EOVERFLOW; |
|
if (flock->l_len > COMPAT_OFF_T_MAX) |
|
flock->l_len = COMPAT_OFF_T_MAX; |
|
return 0; |
|
} |
|
|
|
static long do_compat_fcntl64(unsigned int fd, unsigned int cmd, |
|
compat_ulong_t arg) |
|
{ |
|
struct fd f = fdget_raw(fd); |
|
struct flock flock; |
|
long err = -EBADF; |
|
|
|
if (!f.file) |
|
return err; |
|
|
|
if (unlikely(f.file->f_mode & FMODE_PATH)) { |
|
if (!check_fcntl_cmd(cmd)) |
|
goto out_put; |
|
} |
|
|
|
err = security_file_fcntl(f.file, cmd, arg); |
|
if (err) |
|
goto out_put; |
|
|
|
switch (cmd) { |
|
case F_GETLK: |
|
err = get_compat_flock(&flock, compat_ptr(arg)); |
|
if (err) |
|
break; |
|
err = fcntl_getlk(f.file, convert_fcntl_cmd(cmd), &flock); |
|
if (err) |
|
break; |
|
err = fixup_compat_flock(&flock); |
|
if (!err) |
|
err = put_compat_flock(&flock, compat_ptr(arg)); |
|
break; |
|
case F_GETLK64: |
|
case F_OFD_GETLK: |
|
err = get_compat_flock64(&flock, compat_ptr(arg)); |
|
if (err) |
|
break; |
|
err = fcntl_getlk(f.file, convert_fcntl_cmd(cmd), &flock); |
|
if (!err) |
|
err = put_compat_flock64(&flock, compat_ptr(arg)); |
|
break; |
|
case F_SETLK: |
|
case F_SETLKW: |
|
err = get_compat_flock(&flock, compat_ptr(arg)); |
|
if (err) |
|
break; |
|
err = fcntl_setlk(fd, f.file, convert_fcntl_cmd(cmd), &flock); |
|
break; |
|
case F_SETLK64: |
|
case F_SETLKW64: |
|
case F_OFD_SETLK: |
|
case F_OFD_SETLKW: |
|
err = get_compat_flock64(&flock, compat_ptr(arg)); |
|
if (err) |
|
break; |
|
err = fcntl_setlk(fd, f.file, convert_fcntl_cmd(cmd), &flock); |
|
break; |
|
default: |
|
err = do_fcntl(fd, cmd, arg, f.file); |
|
break; |
|
} |
|
out_put: |
|
fdput(f); |
|
return err; |
|
} |
|
|
|
COMPAT_SYSCALL_DEFINE3(fcntl64, unsigned int, fd, unsigned int, cmd, |
|
compat_ulong_t, arg) |
|
{ |
|
return do_compat_fcntl64(fd, cmd, arg); |
|
} |
|
|
|
COMPAT_SYSCALL_DEFINE3(fcntl, unsigned int, fd, unsigned int, cmd, |
|
compat_ulong_t, arg) |
|
{ |
|
switch (cmd) { |
|
case F_GETLK64: |
|
case F_SETLK64: |
|
case F_SETLKW64: |
|
case F_OFD_GETLK: |
|
case F_OFD_SETLK: |
|
case F_OFD_SETLKW: |
|
return -EINVAL; |
|
} |
|
return do_compat_fcntl64(fd, cmd, arg); |
|
} |
|
#endif |
|
|
|
/* Table to convert sigio signal codes into poll band bitmaps */ |
|
|
|
static const __poll_t band_table[NSIGPOLL] = { |
|
EPOLLIN | EPOLLRDNORM, /* POLL_IN */ |
|
EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND, /* POLL_OUT */ |
|
EPOLLIN | EPOLLRDNORM | EPOLLMSG, /* POLL_MSG */ |
|
EPOLLERR, /* POLL_ERR */ |
|
EPOLLPRI | EPOLLRDBAND, /* POLL_PRI */ |
|
EPOLLHUP | EPOLLERR /* POLL_HUP */ |
|
}; |
|
|
|
static inline int sigio_perm(struct task_struct *p, |
|
struct fown_struct *fown, int sig) |
|
{ |
|
const struct cred *cred; |
|
int ret; |
|
|
|
rcu_read_lock(); |
|
cred = __task_cred(p); |
|
ret = ((uid_eq(fown->euid, GLOBAL_ROOT_UID) || |
|
uid_eq(fown->euid, cred->suid) || uid_eq(fown->euid, cred->uid) || |
|
uid_eq(fown->uid, cred->suid) || uid_eq(fown->uid, cred->uid)) && |
|
!security_file_send_sigiotask(p, fown, sig)); |
|
rcu_read_unlock(); |
|
return ret; |
|
} |
|
|
|
static void send_sigio_to_task(struct task_struct *p, |
|
struct fown_struct *fown, |
|
int fd, int reason, enum pid_type type) |
|
{ |
|
/* |
|
* F_SETSIG can change ->signum lockless in parallel, make |
|
* sure we read it once and use the same value throughout. |
|
*/ |
|
int signum = READ_ONCE(fown->signum); |
|
|
|
if (!sigio_perm(p, fown, signum)) |
|
return; |
|
|
|
switch (signum) { |
|
default: { |
|
kernel_siginfo_t si; |
|
|
|
/* 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 */ |
|
clear_siginfo(&si); |
|
si.si_signo = signum; |
|
si.si_errno = 0; |
|
si.si_code = reason; |
|
/* |
|
* Posix definies POLL_IN and friends to be signal |
|
* specific si_codes for SIG_POLL. Linux extended |
|
* these si_codes to other signals in a way that is |
|
* ambiguous if other signals also have signal |
|
* specific si_codes. In that case use SI_SIGIO instead |
|
* to remove the ambiguity. |
|
*/ |
|
if ((signum != SIGPOLL) && sig_specific_sicodes(signum)) |
|
si.si_code = SI_SIGIO; |
|
|
|
/* Make sure we are called with one of the POLL_* |
|
reasons, otherwise we could leak kernel stack into |
|
userspace. */ |
|
BUG_ON((reason < POLL_IN) || ((reason - POLL_IN) >= NSIGPOLL)); |
|
if (reason - POLL_IN >= NSIGPOLL) |
|
si.si_band = ~0L; |
|
else |
|
si.si_band = mangle_poll(band_table[reason - POLL_IN]); |
|
si.si_fd = fd; |
|
if (!do_send_sig_info(signum, &si, p, type)) |
|
break; |
|
} |
|
fallthrough; /* fall back on the old plain SIGIO signal */ |
|
case 0: |
|
do_send_sig_info(SIGIO, SEND_SIG_PRIV, p, type); |
|
} |
|
} |
|
|
|
void send_sigio(struct fown_struct *fown, int fd, int band) |
|
{ |
|
struct task_struct *p; |
|
enum pid_type type; |
|
unsigned long flags; |
|
struct pid *pid; |
|
|
|
read_lock_irqsave(&fown->lock, flags); |
|
|
|
type = fown->pid_type; |
|
pid = fown->pid; |
|
if (!pid) |
|
goto out_unlock_fown; |
|
|
|
if (type <= PIDTYPE_TGID) { |
|
rcu_read_lock(); |
|
p = pid_task(pid, PIDTYPE_PID); |
|
if (p) |
|
send_sigio_to_task(p, fown, fd, band, type); |
|
rcu_read_unlock(); |
|
} else { |
|
read_lock(&tasklist_lock); |
|
do_each_pid_task(pid, type, p) { |
|
send_sigio_to_task(p, fown, fd, band, type); |
|
} while_each_pid_task(pid, type, p); |
|
read_unlock(&tasklist_lock); |
|
} |
|
out_unlock_fown: |
|
read_unlock_irqrestore(&fown->lock, flags); |
|
} |
|
|
|
static void send_sigurg_to_task(struct task_struct *p, |
|
struct fown_struct *fown, enum pid_type type) |
|
{ |
|
if (sigio_perm(p, fown, SIGURG)) |
|
do_send_sig_info(SIGURG, SEND_SIG_PRIV, p, type); |
|
} |
|
|
|
int send_sigurg(struct fown_struct *fown) |
|
{ |
|
struct task_struct *p; |
|
enum pid_type type; |
|
struct pid *pid; |
|
unsigned long flags; |
|
int ret = 0; |
|
|
|
read_lock_irqsave(&fown->lock, flags); |
|
|
|
type = fown->pid_type; |
|
pid = fown->pid; |
|
if (!pid) |
|
goto out_unlock_fown; |
|
|
|
ret = 1; |
|
|
|
if (type <= PIDTYPE_TGID) { |
|
rcu_read_lock(); |
|
p = pid_task(pid, PIDTYPE_PID); |
|
if (p) |
|
send_sigurg_to_task(p, fown, type); |
|
rcu_read_unlock(); |
|
} else { |
|
read_lock(&tasklist_lock); |
|
do_each_pid_task(pid, type, p) { |
|
send_sigurg_to_task(p, fown, type); |
|
} while_each_pid_task(pid, type, p); |
|
read_unlock(&tasklist_lock); |
|
} |
|
out_unlock_fown: |
|
read_unlock_irqrestore(&fown->lock, flags); |
|
return ret; |
|
} |
|
|
|
static DEFINE_SPINLOCK(fasync_lock); |
|
static struct kmem_cache *fasync_cache __read_mostly; |
|
|
|
static void fasync_free_rcu(struct rcu_head *head) |
|
{ |
|
kmem_cache_free(fasync_cache, |
|
container_of(head, struct fasync_struct, fa_rcu)); |
|
} |
|
|
|
/* |
|
* Remove a fasync entry. If successfully removed, return |
|
* positive and clear the FASYNC flag. If no entry exists, |
|
* do nothing and return 0. |
|
* |
|
* NOTE! It is very important that the FASYNC flag always |
|
* match the state "is the filp on a fasync list". |
|
* |
|
*/ |
|
int fasync_remove_entry(struct file *filp, struct fasync_struct **fapp) |
|
{ |
|
struct fasync_struct *fa, **fp; |
|
int result = 0; |
|
|
|
spin_lock(&filp->f_lock); |
|
spin_lock(&fasync_lock); |
|
for (fp = fapp; (fa = *fp) != NULL; fp = &fa->fa_next) { |
|
if (fa->fa_file != filp) |
|
continue; |
|
|
|
write_lock_irq(&fa->fa_lock); |
|
fa->fa_file = NULL; |
|
write_unlock_irq(&fa->fa_lock); |
|
|
|
*fp = fa->fa_next; |
|
call_rcu(&fa->fa_rcu, fasync_free_rcu); |
|
filp->f_flags &= ~FASYNC; |
|
result = 1; |
|
break; |
|
} |
|
spin_unlock(&fasync_lock); |
|
spin_unlock(&filp->f_lock); |
|
return result; |
|
} |
|
|
|
struct fasync_struct *fasync_alloc(void) |
|
{ |
|
return kmem_cache_alloc(fasync_cache, GFP_KERNEL); |
|
} |
|
|
|
/* |
|
* NOTE! This can be used only for unused fasync entries: |
|
* entries that actually got inserted on the fasync list |
|
* need to be released by rcu - see fasync_remove_entry. |
|
*/ |
|
void fasync_free(struct fasync_struct *new) |
|
{ |
|
kmem_cache_free(fasync_cache, new); |
|
} |
|
|
|
/* |
|
* Insert a new entry into the fasync list. Return the pointer to the |
|
* old one if we didn't use the new one. |
|
* |
|
* NOTE! It is very important that the FASYNC flag always |
|
* match the state "is the filp on a fasync list". |
|
*/ |
|
struct fasync_struct *fasync_insert_entry(int fd, struct file *filp, struct fasync_struct **fapp, struct fasync_struct *new) |
|
{ |
|
struct fasync_struct *fa, **fp; |
|
|
|
spin_lock(&filp->f_lock); |
|
spin_lock(&fasync_lock); |
|
for (fp = fapp; (fa = *fp) != NULL; fp = &fa->fa_next) { |
|
if (fa->fa_file != filp) |
|
continue; |
|
|
|
write_lock_irq(&fa->fa_lock); |
|
fa->fa_fd = fd; |
|
write_unlock_irq(&fa->fa_lock); |
|
goto out; |
|
} |
|
|
|
rwlock_init(&new->fa_lock); |
|
new->magic = FASYNC_MAGIC; |
|
new->fa_file = filp; |
|
new->fa_fd = fd; |
|
new->fa_next = *fapp; |
|
rcu_assign_pointer(*fapp, new); |
|
filp->f_flags |= FASYNC; |
|
|
|
out: |
|
spin_unlock(&fasync_lock); |
|
spin_unlock(&filp->f_lock); |
|
return fa; |
|
} |
|
|
|
/* |
|
* Add a fasync entry. Return negative on error, positive if |
|
* added, and zero if did nothing but change an existing one. |
|
*/ |
|
static int fasync_add_entry(int fd, struct file *filp, struct fasync_struct **fapp) |
|
{ |
|
struct fasync_struct *new; |
|
|
|
new = fasync_alloc(); |
|
if (!new) |
|
return -ENOMEM; |
|
|
|
/* |
|
* fasync_insert_entry() returns the old (update) entry if |
|
* it existed. |
|
* |
|
* So free the (unused) new entry and return 0 to let the |
|
* caller know that we didn't add any new fasync entries. |
|
*/ |
|
if (fasync_insert_entry(fd, filp, fapp, new)) { |
|
fasync_free(new); |
|
return 0; |
|
} |
|
|
|
return 1; |
|
} |
|
|
|
/* |
|
* fasync_helper() is used by almost all character device drivers |
|
* to set up the fasync queue, and for regular files by the file |
|
* lease code. 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) |
|
{ |
|
if (!on) |
|
return fasync_remove_entry(filp, fapp); |
|
return fasync_add_entry(fd, filp, fapp); |
|
} |
|
|
|
EXPORT_SYMBOL(fasync_helper); |
|
|
|
/* |
|
* rcu_read_lock() is held |
|
*/ |
|
static void kill_fasync_rcu(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; |
|
} |
|
read_lock(&fa->fa_lock); |
|
if (fa->fa_file) { |
|
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); |
|
} |
|
read_unlock(&fa->fa_lock); |
|
fa = rcu_dereference(fa->fa_next); |
|
} |
|
} |
|
|
|
void kill_fasync(struct fasync_struct **fp, int sig, int band) |
|
{ |
|
/* First a quick test without locking: usually |
|
* the list is empty. |
|
*/ |
|
if (*fp) { |
|
rcu_read_lock(); |
|
kill_fasync_rcu(rcu_dereference(*fp), sig, band); |
|
rcu_read_unlock(); |
|
} |
|
} |
|
EXPORT_SYMBOL(kill_fasync); |
|
|
|
static int __init fcntl_init(void) |
|
{ |
|
/* |
|
* Please add new bits here to ensure allocation uniqueness. |
|
* Exceptions: O_NONBLOCK is a two bit define on parisc; O_NDELAY |
|
* is defined as O_NONBLOCK on some platforms and not on others. |
|
*/ |
|
BUILD_BUG_ON(21 - 1 /* for O_RDONLY being 0 */ != |
|
HWEIGHT32( |
|
(VALID_OPEN_FLAGS & ~(O_NONBLOCK | O_NDELAY)) | |
|
__FMODE_EXEC | __FMODE_NONOTIFY)); |
|
|
|
fasync_cache = kmem_cache_create("fasync_cache", |
|
sizeof(struct fasync_struct), 0, SLAB_PANIC, NULL); |
|
return 0; |
|
} |
|
|
|
module_init(fcntl_init)
|
|
|