X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;ds=sidebyside;f=fs%2Ffcntl.c;h=97e01dc0d95fc4fe8464d729ce94d32b888b567d;hb=e071041be037eca208b62b84469a06bdfc692bea;hp=04df8570a2d23c88f6340dd74bfb8bd7607a2cc8;hpb=db1dd4d376134eba0e08af523b61cc566a4ea1cd;p=safe%2Fjmp%2Flinux-2.6 diff --git a/fs/fcntl.c b/fs/fcntl.c index 04df857..97e01dc 100644 --- a/fs/fcntl.c +++ b/fs/fcntl.c @@ -19,7 +19,6 @@ #include #include #include -#include #include #include @@ -117,11 +116,13 @@ SYSCALL_DEFINE2(dup2, unsigned int, oldfd, unsigned int, newfd) { if (unlikely(newfd == oldfd)) { /* corner case */ struct files_struct *files = current->files; + int retval = oldfd; + rcu_read_lock(); if (!fcheck_files(files, oldfd)) - oldfd = -EBADF; + retval = -EBADF; rcu_read_unlock(); - return oldfd; + return retval; } return sys_dup3(oldfd, newfd, 0); } @@ -141,7 +142,7 @@ SYSCALL_DEFINE1(dup, unsigned int, fildes) return ret; } -#define SETFL_MASK (O_APPEND | O_NONBLOCK | O_NDELAY | FASYNC | O_DIRECT | O_NOATIME) +#define SETFL_MASK (O_APPEND | O_NONBLOCK | O_NDELAY | O_DIRECT | O_NOATIME) static int setfl(int fd, struct file * filp, unsigned long arg) { @@ -177,36 +178,38 @@ static int setfl(int fd, struct file * filp, unsigned long arg) return error; /* - * We still need a lock here for now to keep multiple FASYNC calls - * from racing with each other. + * ->fasync() is responsible for setting the FASYNC bit. */ - 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; - } + if (((arg ^ filp->f_flags) & FASYNC) && filp->f_op && + 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); spin_unlock(&filp->f_lock); + out: - unlock_kernel(); return error; } static void f_modown(struct file *filp, struct pid *pid, enum pid_type type, - uid_t uid, uid_t euid, int force) + int force) { write_lock_irq(&filp->f_owner.lock); if (force || !filp->f_owner.pid) { put_pid(filp->f_owner.pid); filp->f_owner.pid = get_pid(pid); filp->f_owner.pid_type = type; - filp->f_owner.uid = uid; - filp->f_owner.euid = euid; + + if (pid) { + const struct cred *cred = current_cred(); + filp->f_owner.uid = cred->uid; + filp->f_owner.euid = cred->euid; + } } write_unlock_irq(&filp->f_owner.lock); } @@ -214,14 +217,13 @@ static void f_modown(struct file *filp, struct pid *pid, enum pid_type type, int __f_setown(struct file *filp, struct pid *pid, enum pid_type type, int force) { - const struct cred *cred = current_cred(); int err; - + err = security_file_set_fowner(filp); if (err) return err; - f_modown(filp, pid, type, cred->uid, cred->euid, force); + f_modown(filp, pid, type, force); return 0; } EXPORT_SYMBOL(__f_setown); @@ -247,7 +249,7 @@ EXPORT_SYMBOL(f_setown); void f_delown(struct file *filp) { - f_modown(filp, NULL, PIDTYPE_PID, 0, 0, 1); + f_modown(filp, NULL, PIDTYPE_PID, 1); } pid_t f_getown(struct file *filp) @@ -261,6 +263,79 @@ pid_t f_getown(struct file *filp) 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 ret; + + switch (owner.type) { + case F_OWNER_TID: + type = PIDTYPE_MAX; + break; + + case F_OWNER_PID: + type = PIDTYPE_PID; + break; + + case F_OWNER_PGRP: + type = PIDTYPE_PGID; + break; + + default: + return -EINVAL; + } + + rcu_read_lock(); + pid = find_vpid(owner.pid); + if (owner.pid && !pid) + ret = -ESRCH; + else + ret = __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; + + read_lock(&filp->f_owner.lock); + owner.pid = pid_vnr(filp->f_owner.pid); + switch (filp->f_owner.pid_type) { + case PIDTYPE_MAX: + owner.type = F_OWNER_TID; + break; + + case PIDTYPE_PID: + owner.type = F_OWNER_PID; + break; + + case PIDTYPE_PGID: + owner.type = F_OWNER_PGRP; + break; + + default: + WARN_ON(1); + ret = -EINVAL; + break; + } + read_unlock(&filp->f_owner.lock); + + if (!ret) + ret = copy_to_user(owner_p, &owner, sizeof(owner)); + return ret; +} + static long do_fcntl(int fd, unsigned int cmd, unsigned long arg, struct file *filp) { @@ -311,6 +386,12 @@ static long do_fcntl(int fd, unsigned int cmd, unsigned long arg, case F_SETOWN: err = f_setown(filp, arg, 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_GETSIG: err = filp->f_owner.signum; break; @@ -425,14 +506,19 @@ static inline int sigio_perm(struct task_struct *p, } static void send_sigio_to_task(struct task_struct *p, - struct fown_struct *fown, - int fd, - int reason) + struct fown_struct *fown, + int fd, int reason, int group) { - if (!sigio_perm(p, fown, fown->signum)) + /* + * F_SETSIG can change ->signum lockless in parallel, make + * sure we read it once and use the same value throughout. + */ + int signum = ACCESS_ONCE(fown->signum); + + if (!sigio_perm(p, fown, signum)) return; - switch (fown->signum) { + switch (signum) { siginfo_t si; default: /* Queue a rt signal with the appropriate fd as its @@ -441,7 +527,7 @@ static void send_sigio_to_task(struct task_struct *p, 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_signo = signum; si.si_errno = 0; si.si_code = reason; /* Make sure we are called with one of the POLL_* @@ -453,11 +539,11 @@ static void send_sigio_to_task(struct task_struct *p, else si.si_band = band_table[reason - POLL_IN]; si.si_fd = fd; - if (!group_send_sig_info(fown->signum, &si, p)) + if (!do_send_sig_info(signum, &si, p, group)) break; /* fall-through: fall back on the old plain SIGIO signal */ case 0: - group_send_sig_info(SIGIO, SEND_SIG_PRIV, p); + do_send_sig_info(SIGIO, SEND_SIG_PRIV, p, group); } } @@ -466,16 +552,23 @@ void send_sigio(struct fown_struct *fown, int fd, int band) struct task_struct *p; enum pid_type type; struct pid *pid; + int group = 1; read_lock(&fown->lock); + type = fown->pid_type; + if (type == PIDTYPE_MAX) { + group = 0; + type = PIDTYPE_PID; + } + pid = fown->pid; if (!pid) goto out_unlock_fown; read_lock(&tasklist_lock); do_each_pid_task(pid, type, p) { - send_sigio_to_task(p, fown, fd, band); + send_sigio_to_task(p, fown, fd, band, group); } while_each_pid_task(pid, type, p); read_unlock(&tasklist_lock); out_unlock_fown: @@ -483,10 +576,10 @@ void send_sigio(struct fown_struct *fown, int fd, int band) } static void send_sigurg_to_task(struct task_struct *p, - struct fown_struct *fown) + struct fown_struct *fown, int group) { if (sigio_perm(p, fown, SIGURG)) - group_send_sig_info(SIGURG, SEND_SIG_PRIV, p); + do_send_sig_info(SIGURG, SEND_SIG_PRIV, p, group); } int send_sigurg(struct fown_struct *fown) @@ -494,10 +587,17 @@ int send_sigurg(struct fown_struct *fown) struct task_struct *p; enum pid_type type; struct pid *pid; + int group = 1; int ret = 0; read_lock(&fown->lock); + type = fown->pid_type; + if (type == PIDTYPE_MAX) { + group = 0; + type = PIDTYPE_PID; + } + pid = fown->pid; if (!pid) goto out_unlock_fown; @@ -506,7 +606,7 @@ int send_sigurg(struct fown_struct *fown) read_lock(&tasklist_lock); do_each_pid_task(pid, type, p) { - send_sigurg_to_task(p, fown); + send_sigurg_to_task(p, fown, group); } while_each_pid_task(pid, type, p); read_unlock(&tasklist_lock); out_unlock_fown: @@ -518,49 +618,90 @@ static DEFINE_RWLOCK(fasync_lock); static struct kmem_cache *fasync_cache __read_mostly; /* - * 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. + * 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". + * + * We always take the 'filp->f_lock', in since fasync_lock + * needs to be irq-safe. */ -int fasync_helper(int fd, struct file * filp, int on, struct fasync_struct **fapp) +static int fasync_remove_entry(struct file *filp, 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, GFP_KERNEL); - if (!new) - return -ENOMEM; - } + spin_lock(&filp->f_lock); 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 (fa->fa_file != filp) + continue; + *fp = fa->fa_next; + kmem_cache_free(fasync_cache, fa); + filp->f_flags &= ~FASYNC; + result = 1; + break; } + write_unlock_irq(&fasync_lock); + spin_unlock(&filp->f_lock); + return result; +} - if (on) { - new->magic = FASYNC_MAGIC; - new->fa_file = filp; - new->fa_fd = fd; - new->fa_next = *fapp; - *fapp = new; - result = 1; +/* + * Add a fasync entry. Return negative on error, positive if + * added, and zero if did nothing but change an existing one. + * + * NOTE! It is very important that the FASYNC flag always + * match the state "is the filp on a fasync list". + */ +static int fasync_add_entry(int fd, struct file *filp, struct fasync_struct **fapp) +{ + struct fasync_struct *new, *fa, **fp; + int result = 0; + + new = kmem_cache_alloc(fasync_cache, GFP_KERNEL); + if (!new) + return -ENOMEM; + + spin_lock(&filp->f_lock); + write_lock_irq(&fasync_lock); + for (fp = fapp; (fa = *fp) != NULL; fp = &fa->fa_next) { + if (fa->fa_file != filp) + continue; + fa->fa_fd = fd; + kmem_cache_free(fasync_cache, new); + goto out; } + + new->magic = FASYNC_MAGIC; + new->fa_file = filp; + new->fa_fd = fd; + new->fa_next = *fapp; + *fapp = new; + result = 1; + filp->f_flags |= FASYNC; + out: write_unlock_irq(&fasync_lock); + spin_unlock(&filp->f_lock); return result; } +/* + * 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); void __kill_fasync(struct fasync_struct *fa, int sig, int band)