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(I'm so sorry!) Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel os linux
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#include <linux/syscalls.h>#include <linux/init.h>#include <linux/mm.h>#include <linux/sched/task.h>#include <linux/fs.h>#include <linux/filelock.h>#include <linux/file.h>#include <linux/capability.h>#include <linux/dnotify.h>#include <linux/slab.h>#include <linux/module.h>#include <linux/pipe_fs_i.h>#include <linux/security.h>#include <linux/ptrace.h>#include <linux/signal.h>#include <linux/rcupdate.h>#include <linux/pid_namespace.h>#include <linux/user_namespace.h>#include <linux/memfd.h>#include <linux/compat.h>#include <linux/mount.h>#include <linux/rw_hint.h>
#include <linux/poll.h>#include <asm/siginfo.h>#include <linux/uaccess.h>
#include "internal.h"
#define SETFL_MASK (O_APPEND | O_NONBLOCK | O_NDELAY | O_DIRECT | O_NOATIME)
static int setfl(int fd, struct file * filp, unsigned int arg){ struct inode * inode = file_inode(filp); int error = 0;
/* * O_APPEND cannot be cleared if the file is marked as append-only * and the file is open for write. */ if (((arg ^ filp->f_flags) & 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 (!inode_owner_or_capable(file_mnt_idmap(filp), inode)) return -EPERM;
/* required for strict SunOS emulation */ if (O_NONBLOCK != O_NDELAY) if (arg & O_NDELAY) arg |= O_NONBLOCK;
/* Pipe packetized mode is controlled by O_DIRECT flag */ if (!S_ISFIFO(inode->i_mode) && (arg & O_DIRECT) && !(filp->f_mode & FMODE_CAN_ODIRECT)) return -EINVAL;
if (filp->f_op->check_flags) error = filp->f_op->check_flags(arg); if (error) return error;
/* * ->fasync() is responsible for setting the FASYNC bit. */ if (((arg ^ filp->f_flags) & FASYNC) && filp->f_op->fasync) { error = filp->f_op->fasync(fd, filp, (arg & FASYNC) != 0); if (error < 0) goto out; if (error > 0) error = 0; } spin_lock(&filp->f_lock); filp->f_flags = (arg & SETFL_MASK) | (filp->f_flags & ~SETFL_MASK); filp->f_iocb_flags = iocb_flags(filp); spin_unlock(&filp->f_lock);
out: return error;}
/* * Allocate an file->f_owner struct if it doesn't exist, handling racing * allocations correctly. */int file_f_owner_allocate(struct file *file){ struct fown_struct *f_owner;
f_owner = file_f_owner(file); if (f_owner) return 0;
f_owner = kzalloc_obj(struct fown_struct); if (!f_owner) return -ENOMEM;
rwlock_init(&f_owner->lock); f_owner->file = file; /* If someone else raced us, drop our allocation. */ if (unlikely(cmpxchg(&file->f_owner, NULL, f_owner))) kfree(f_owner); return 0;}EXPORT_SYMBOL(file_f_owner_allocate);
void file_f_owner_release(struct file *file){ struct fown_struct *f_owner;
f_owner = file_f_owner(file); if (f_owner) { put_pid(f_owner->pid); kfree(f_owner); }}
void __f_setown(struct file *filp, struct pid *pid, enum pid_type type, int force){ struct fown_struct *f_owner;
f_owner = file_f_owner(filp); if (WARN_ON_ONCE(!f_owner)) return;
write_lock_irq(&f_owner->lock); if (force || !f_owner->pid) { put_pid(f_owner->pid); f_owner->pid = get_pid(pid); f_owner->pid_type = type;
if (pid) { const struct cred *cred = current_cred(); security_file_set_fowner(filp); f_owner->uid = cred->uid; f_owner->euid = cred->euid; } } write_unlock_irq(&f_owner->lock);}EXPORT_SYMBOL(__f_setown);
int f_setown(struct file *filp, int who, int force){ enum pid_type type; struct pid *pid = NULL; int ret = 0;
might_sleep();
type = PIDTYPE_TGID; if (who < 0) { /* avoid overflow below */ if (who == INT_MIN) return -EINVAL;
type = PIDTYPE_PGID; who = -who; }
ret = file_f_owner_allocate(filp); if (ret) return ret;
rcu_read_lock(); if (who) { pid = find_vpid(who); if (!pid) ret = -ESRCH; }
if (!ret) __f_setown(filp, pid, type, force); rcu_read_unlock();
return ret;}EXPORT_SYMBOL(f_setown);
void f_delown(struct file *filp){ __f_setown(filp, NULL, PIDTYPE_TGID, 1);}
pid_t f_getown(struct file *filp){ pid_t pid = 0; struct fown_struct *f_owner;
f_owner = file_f_owner(filp); if (!f_owner) return pid;
read_lock_irq(&f_owner->lock); rcu_read_lock(); if (pid_task(f_owner->pid, f_owner->pid_type)) { pid = pid_vnr(f_owner->pid); if (f_owner->pid_type == PIDTYPE_PGID) pid = -pid; } rcu_read_unlock(); read_unlock_irq(&f_owner->lock); return pid;}
static int f_setown_ex(struct file *filp, unsigned long arg){ struct f_owner_ex __user *owner_p = (void __user *)arg; struct f_owner_ex owner; struct pid *pid; int type; int ret;
ret = copy_from_user(&owner, owner_p, sizeof(owner)); if (ret) return -EFAULT;
switch (owner.type) { case F_OWNER_TID: type = PIDTYPE_PID; break;
case F_OWNER_PID: type = PIDTYPE_TGID; break;
case F_OWNER_PGRP: type = PIDTYPE_PGID; break;
default: return -EINVAL; }
ret = file_f_owner_allocate(filp); if (ret) return ret;
rcu_read_lock(); pid = find_vpid(owner.pid); if (owner.pid && !pid) ret = -ESRCH; else __f_setown(filp, pid, type, 1); rcu_read_unlock();
return ret;}
static int f_getown_ex(struct file *filp, unsigned long arg){ struct f_owner_ex __user *owner_p = (void __user *)arg; struct f_owner_ex owner = {}; int ret = 0; struct fown_struct *f_owner; enum pid_type pid_type = PIDTYPE_PID;
f_owner = file_f_owner(filp); if (f_owner) { read_lock_irq(&f_owner->lock); rcu_read_lock(); if (pid_task(f_owner->pid, f_owner->pid_type)) owner.pid = pid_vnr(f_owner->pid); rcu_read_unlock(); pid_type = f_owner->pid_type; }
switch (pid_type) { case PIDTYPE_PID: owner.type = F_OWNER_TID; break;
case PIDTYPE_TGID: owner.type = F_OWNER_PID; break;
case PIDTYPE_PGID: owner.type = F_OWNER_PGRP; break;
default: WARN_ON(1); ret = -EINVAL; break; } if (f_owner) read_unlock_irq(&f_owner->lock);
if (!ret) { ret = copy_to_user(owner_p, &owner, sizeof(owner)); if (ret) ret = -EFAULT; } return ret;}
#ifdef CONFIG_CHECKPOINT_RESTOREstatic int f_getowner_uids(struct file *filp, unsigned long arg){ struct user_namespace *user_ns = current_user_ns(); struct fown_struct *f_owner; uid_t __user *dst = (void __user *)arg; uid_t src[2] = {0, 0}; int err;
f_owner = file_f_owner(filp); if (f_owner) { read_lock_irq(&f_owner->lock); src[0] = from_kuid(user_ns, f_owner->uid); src[1] = from_kuid(user_ns, f_owner->euid); read_unlock_irq(&f_owner->lock); }
err = put_user(src[0], &dst[0]); err |= put_user(src[1], &dst[1]);
return err;}#elsestatic int f_getowner_uids(struct file *filp, unsigned long arg){ return -EINVAL;}#endif
static bool rw_hint_valid(u64 hint){ BUILD_BUG_ON(WRITE_LIFE_NOT_SET != RWH_WRITE_LIFE_NOT_SET); BUILD_BUG_ON(WRITE_LIFE_NONE != RWH_WRITE_LIFE_NONE); BUILD_BUG_ON(WRITE_LIFE_SHORT != RWH_WRITE_LIFE_SHORT); BUILD_BUG_ON(WRITE_LIFE_MEDIUM != RWH_WRITE_LIFE_MEDIUM); BUILD_BUG_ON(WRITE_LIFE_LONG != RWH_WRITE_LIFE_LONG); BUILD_BUG_ON(WRITE_LIFE_EXTREME != RWH_WRITE_LIFE_EXTREME);
switch (hint) { case RWH_WRITE_LIFE_NOT_SET: case RWH_WRITE_LIFE_NONE: case RWH_WRITE_LIFE_SHORT: case RWH_WRITE_LIFE_MEDIUM: case RWH_WRITE_LIFE_LONG: case RWH_WRITE_LIFE_EXTREME: return true; default: return false; }}
static long fcntl_get_rw_hint(struct file *file, unsigned long arg){ struct inode *inode = file_inode(file); u64 __user *argp = (u64 __user *)arg; u64 hint = READ_ONCE(inode->i_write_hint);
if (copy_to_user(argp, &hint, sizeof(*argp))) return -EFAULT; return 0;}
static long fcntl_set_rw_hint(struct file *file, unsigned long arg){ struct inode *inode = file_inode(file); u64 __user *argp = (u64 __user *)arg; u64 hint;
/* nothing is ever written to it */ if (IS_IMMUTABLE(inode)) return -EPERM; if (!inode_owner_or_capable(file_mnt_idmap(file), inode)) return -EPERM;
if (copy_from_user(&hint, argp, sizeof(hint))) return -EFAULT; if (!rw_hint_valid(hint)) return -EINVAL;
WRITE_ONCE(inode->i_write_hint, hint);
/* * file->f_mapping->host may differ from inode. As an example, * blkdev_open() modifies file->f_mapping. */ if (file->f_mapping->host != inode) WRITE_ONCE(file->f_mapping->host->i_write_hint, hint);
return 0;}
/* Is the file descriptor a dup of the file? */static long f_dupfd_query(int fd, struct file *filp){ CLASS(fd_raw, f)(fd);
if (fd_empty(f)) return -EBADF;
/* * We can do the 'fdput()' immediately, as the only thing that * matters is the pointer value which isn't changed by the fdput. * * Technically we didn't need a ref at all, and 'fdget()' was * overkill, but given our lockless file pointer lookup, the * alternatives are complicated. */ return fd_file(f) == filp;}
/* Let the caller figure out whether a given file was just created. */static long f_created_query(const struct file *filp){ return !!(filp->f_mode & FMODE_CREATED);}
static int f_owner_sig(struct file *filp, int signum, bool setsig){ int ret = 0; struct fown_struct *f_owner;
might_sleep();
if (setsig) { if (!valid_signal(signum)) return -EINVAL;
ret = file_f_owner_allocate(filp); if (ret) return ret; }
f_owner = file_f_owner(filp); if (setsig) f_owner->signum = signum; else if (f_owner) ret = f_owner->signum; return ret;}
static long do_fcntl(int fd, unsigned int cmd, unsigned long arg, struct file *filp){ void __user *argp = (void __user *)arg; struct delegation deleg; int argi = (int)arg; struct flock flock; long err = -EINVAL;
switch (cmd) { case F_CREATED_QUERY: err = f_created_query(filp); break; case F_DUPFD: err = f_dupfd(argi, filp, 0); break; case F_DUPFD_CLOEXEC: err = f_dupfd(argi, filp, O_CLOEXEC); break; case F_DUPFD_QUERY: err = f_dupfd_query(argi, filp); break; case F_GETFD: err = get_close_on_exec(fd) ? FD_CLOEXEC : 0; break; case F_SETFD: err = 0; set_close_on_exec(fd, argi & FD_CLOEXEC); break; case F_GETFL: err = filp->f_flags; break; case F_SETFL: err = setfl(fd, filp, argi); break;#if BITS_PER_LONG != 32 /* 32-bit arches must use fcntl64() */ case F_OFD_GETLK:#endif case F_GETLK: if (copy_from_user(&flock, argp, sizeof(flock))) return -EFAULT; err = fcntl_getlk(filp, cmd, &flock); if (!err && copy_to_user(argp, &flock, sizeof(flock))) return -EFAULT; break;#if BITS_PER_LONG != 32 /* 32-bit arches must use fcntl64() */ case F_OFD_SETLK: case F_OFD_SETLKW: fallthrough;#endif case F_SETLK: case F_SETLKW: if (copy_from_user(&flock, argp, sizeof(flock))) return -EFAULT; err = fcntl_setlk(fd, filp, cmd, &flock); 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 = f_getown(filp); force_successful_syscall_return(); break; case F_SETOWN: err = f_setown(filp, argi, 1); break; case F_GETOWN_EX: err = f_getown_ex(filp, arg); break; case F_SETOWN_EX: err = f_setown_ex(filp, arg); break; case F_GETOWNER_UIDS: err = f_getowner_uids(filp, arg); break; case F_GETSIG: err = f_owner_sig(filp, 0, false); break; case F_SETSIG: err = f_owner_sig(filp, argi, true); break; case F_GETLEASE: err = fcntl_getlease(filp); break; case F_SETLEASE: err = fcntl_setlease(fd, filp, argi); break; case F_NOTIFY: err = fcntl_dirnotify(fd, filp, argi); break; case F_SETPIPE_SZ: case F_GETPIPE_SZ: err = pipe_fcntl(filp, cmd, argi); break; case F_ADD_SEALS: case F_GET_SEALS: err = memfd_fcntl(filp, cmd, argi); break; case F_GET_RW_HINT: err = fcntl_get_rw_hint(filp, arg); break; case F_SET_RW_HINT: err = fcntl_set_rw_hint(filp, arg); break; case F_GETDELEG: if (copy_from_user(&deleg, argp, sizeof(deleg))) return -EFAULT; err = fcntl_getdeleg(filp, &deleg); if (!err && copy_to_user(argp, &deleg, sizeof(deleg))) return -EFAULT; break; case F_SETDELEG: if (copy_from_user(&deleg, argp, sizeof(deleg))) return -EFAULT; err = fcntl_setdeleg(fd, filp, &deleg); break; default: break; } return err;}
static int check_fcntl_cmd(unsigned cmd){ switch (cmd) { case F_CREATED_QUERY: case F_DUPFD: case F_DUPFD_CLOEXEC: case F_DUPFD_QUERY: case F_GETFD: case F_SETFD: case F_GETFL: return 1; } return 0;}
SYSCALL_DEFINE3(fcntl, unsigned int, fd, unsigned int, cmd, unsigned long, arg){ CLASS(fd_raw, f)(fd); long err;
if (fd_empty(f)) return -EBADF;
if (unlikely(fd_file(f)->f_mode & FMODE_PATH)) { if (!check_fcntl_cmd(cmd)) return -EBADF; }
err = security_file_fcntl(fd_file(f), cmd, arg); if (!err) err = do_fcntl(fd, cmd, arg, fd_file(f));
return err;}
#if BITS_PER_LONG == 32SYSCALL_DEFINE3(fcntl64, unsigned int, fd, unsigned int, cmd, unsigned long, arg){ void __user *argp = (void __user *)arg; CLASS(fd_raw, f)(fd); struct flock64 flock; long err;
if (fd_empty(f)) return -EBADF;
if (unlikely(fd_file(f)->f_mode & FMODE_PATH)) { if (!check_fcntl_cmd(cmd)) return -EBADF; }
err = security_file_fcntl(fd_file(f), cmd, arg); if (err) return err; switch (cmd) { case F_GETLK64: case F_OFD_GETLK: err = -EFAULT; if (copy_from_user(&flock, argp, sizeof(flock))) break; err = fcntl_getlk64(fd_file(f), cmd, &flock); if (!err && copy_to_user(argp, &flock, sizeof(flock))) err = -EFAULT; break; case F_SETLK64: case F_SETLKW64: case F_OFD_SETLK: case F_OFD_SETLKW: err = -EFAULT; if (copy_from_user(&flock, argp, sizeof(flock))) break; err = fcntl_setlk64(fd, fd_file(f), cmd, &flock); break; default: err = do_fcntl(fd, cmd, arg, fd_file(f)); break; } return err;}#endif
#ifdef CONFIG_COMPAT/* careful - don't use anywhere else */#define copy_flock_fields(dst, src) \ (dst)->l_type = (src)->l_type; \ (dst)->l_whence = (src)->l_whence; \ (dst)->l_start = (src)->l_start; \ (dst)->l_len = (src)->l_len; \ (dst)->l_pid = (src)->l_pid;
static int get_compat_flock(struct flock *kfl, const struct compat_flock __user *ufl){ struct compat_flock fl;
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){ struct compat_flock fl;
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 intconvert_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){ CLASS(fd_raw, f)(fd); struct flock flock; long err;
if (fd_empty(f)) return -EBADF;
if (unlikely(fd_file(f)->f_mode & FMODE_PATH)) { if (!check_fcntl_cmd(cmd)) return -EBADF; }
err = security_file_fcntl(fd_file(f), cmd, arg); if (err) return err;
switch (cmd) { case F_GETLK: err = get_compat_flock(&flock, compat_ptr(arg)); if (err) break; err = fcntl_getlk(fd_file(f), 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(fd_file(f), 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, fd_file(f), 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, fd_file(f), convert_fcntl_cmd(cmd), &flock); break; default: err = do_fcntl(fd, cmd, arg, fd_file(f)); break; } 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 { rcu_read_lock(); do_each_pid_task(pid, type, p) { send_sigio_to_task(p, fown, fd, band, type); } while_each_pid_task(pid, type, p); rcu_read_unlock(); } 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 file *file){ struct fown_struct *fown; struct task_struct *p; enum pid_type type; struct pid *pid; unsigned long flags; int ret = 0; fown = file_f_owner(file); if (!fown) return 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 { rcu_read_lock(); do_each_pid_task(pid, type, p) { send_sigurg_to_task(p, fown, type); } while_each_pid_task(pid, type, p); rcu_read_unlock(); } out_unlock_fown: read_unlock_irqrestore(&fown->lock, flags); return ret;}
static DEFINE_SPINLOCK(fasync_lock);static struct kmem_cache *fasync_cache __ro_after_init;
/* * 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; kfree_rcu(fa, fa_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; unsigned long flags;
if (fa->magic != FASYNC_MAGIC) { printk(KERN_ERR "kill_fasync: bad magic number in " "fasync_struct!\n"); return; } read_lock_irqsave(&fa->fa_lock, flags); if (fa->fa_file) { fown = file_f_owner(fa->fa_file); if (!fown) goto next; /* 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); }next: read_unlock_irqrestore(&fa->fa_lock, flags); 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(22 - 1 /* for O_RDONLY being 0 */ != HWEIGHT32( (VALID_OPEN_FLAGS & ~(O_NONBLOCK | O_NDELAY)) | __FMODE_EXEC | __O_REGULAR));
fasync_cache = kmem_cache_create("fasync_cache", sizeof(struct fasync_struct), 0, SLAB_PANIC | SLAB_ACCOUNT, NULL); return 0;}
module_init(fcntl_init)