diff options
| -rw-r--r-- | fs/fcntl.c | 131 | ||||
| -rw-r--r-- | fs/file.c | 132 | ||||
| -rw-r--r-- | include/linux/file.h | 2 |
3 files changed, 137 insertions, 128 deletions
@@ -26,127 +26,6 @@ #include <asm/siginfo.h> #include <asm/uaccess.h> -void set_close_on_exec(unsigned int fd, int flag) -{ - struct files_struct *files = current->files; - struct fdtable *fdt; - spin_lock(&files->file_lock); - fdt = files_fdtable(files); - if (flag) - __set_close_on_exec(fd, fdt); - else - __clear_close_on_exec(fd, fdt); - spin_unlock(&files->file_lock); -} - -static bool get_close_on_exec(unsigned int fd) -{ - struct files_struct *files = current->files; - struct fdtable *fdt; - bool res; - rcu_read_lock(); - fdt = files_fdtable(files); - res = close_on_exec(fd, fdt); - rcu_read_unlock(); - return res; -} - -SYSCALL_DEFINE3(dup3, unsigned int, oldfd, unsigned int, newfd, int, flags) -{ - int err = -EBADF; - struct file * file, *tofree; - struct files_struct * files = current->files; - struct fdtable *fdt; - - if ((flags & ~O_CLOEXEC) != 0) - return -EINVAL; - - if (unlikely(oldfd == newfd)) - return -EINVAL; - - if (newfd >= rlimit(RLIMIT_NOFILE)) - return -EMFILE; - - spin_lock(&files->file_lock); - err = expand_files(files, newfd); - file = fcheck(oldfd); - if (unlikely(!file)) - goto Ebadf; - if (unlikely(err < 0)) { - if (err == -EMFILE) - goto Ebadf; - goto out_unlock; - } - /* - * We need to detect attempts to do dup2() over allocated but still - * not finished descriptor. NB: OpenBSD avoids that at the price of - * extra work in their equivalent of fget() - they insert struct - * file immediately after grabbing descriptor, mark it larval if - * more work (e.g. actual opening) is needed and make sure that - * fget() treats larval files as absent. Potentially interesting, - * but while extra work in fget() is trivial, locking implications - * and amount of surgery on open()-related paths in VFS are not. - * FreeBSD fails with -EBADF in the same situation, NetBSD "solution" - * deadlocks in rather amusing ways, AFAICS. All of that is out of - * scope of POSIX or SUS, since neither considers shared descriptor - * tables and this condition does not arise without those. - */ - err = -EBUSY; - fdt = files_fdtable(files); - tofree = fdt->fd[newfd]; - if (!tofree && fd_is_open(newfd, fdt)) - goto out_unlock; - get_file(file); - rcu_assign_pointer(fdt->fd[newfd], file); - __set_open_fd(newfd, fdt); - if (flags & O_CLOEXEC) - __set_close_on_exec(newfd, fdt); - else - __clear_close_on_exec(newfd, fdt); - spin_unlock(&files->file_lock); - - if (tofree) - filp_close(tofree, files); - - return newfd; - -Ebadf: - err = -EBADF; -out_unlock: - spin_unlock(&files->file_lock); - return err; -} - -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)) - retval = -EBADF; - rcu_read_unlock(); - return retval; - } - return sys_dup3(oldfd, newfd, 0); -} - -SYSCALL_DEFINE1(dup, unsigned int, fildes) -{ - int ret = -EBADF; - struct file *file = fget_raw(fildes); - - if (file) { - ret = get_unused_fd(); - if (ret >= 0) - fd_install(ret, file); - else - fput(file); - } - return ret; -} - #define SETFL_MASK (O_APPEND | O_NONBLOCK | O_NDELAY | O_DIRECT | O_NOATIME) static int setfl(int fd, struct file * filp, unsigned long arg) @@ -376,14 +255,10 @@ static long do_fcntl(int fd, unsigned int cmd, unsigned long arg, switch (cmd) { case F_DUPFD: + err = f_dupfd(arg, filp, 0); + break; case F_DUPFD_CLOEXEC: - if (arg >= rlimit(RLIMIT_NOFILE)) - break; - err = alloc_fd(arg, cmd == F_DUPFD_CLOEXEC ? O_CLOEXEC : 0); - if (err >= 0) { - get_file(filp); - fd_install(err, filp); - } + err = f_dupfd(arg, filp, FD_CLOEXEC); break; case F_GETFD: err = get_close_on_exec(fd) ? FD_CLOEXEC : 0; @@ -6,6 +6,7 @@ * Manage the dynamic fd arrays in the process files_struct. */ +#include <linux/syscalls.h> #include <linux/export.h> #include <linux/fs.h> #include <linux/mm.h> @@ -794,3 +795,134 @@ struct file *fget_raw_light(unsigned int fd, int *fput_needed) return file; } + +void set_close_on_exec(unsigned int fd, int flag) +{ + struct files_struct *files = current->files; + struct fdtable *fdt; + spin_lock(&files->file_lock); + fdt = files_fdtable(files); + if (flag) + __set_close_on_exec(fd, fdt); + else + __clear_close_on_exec(fd, fdt); + spin_unlock(&files->file_lock); +} + +bool get_close_on_exec(unsigned int fd) +{ + struct files_struct *files = current->files; + struct fdtable *fdt; + bool res; + rcu_read_lock(); + fdt = files_fdtable(files); + res = close_on_exec(fd, fdt); + rcu_read_unlock(); + return res; +} + +SYSCALL_DEFINE3(dup3, unsigned int, oldfd, unsigned int, newfd, int, flags) +{ + int err = -EBADF; + struct file * file, *tofree; + struct files_struct * files = current->files; + struct fdtable *fdt; + + if ((flags & ~O_CLOEXEC) != 0) + return -EINVAL; + + if (newfd >= rlimit(RLIMIT_NOFILE)) + return -EMFILE; + + spin_lock(&files->file_lock); + err = expand_files(files, newfd); + file = fcheck(oldfd); + if (unlikely(!file)) + goto Ebadf; + if (unlikely(err < 0)) { + if (err == -EMFILE) + goto Ebadf; + goto out_unlock; + } + /* + * We need to detect attempts to do dup2() over allocated but still + * not finished descriptor. NB: OpenBSD avoids that at the price of + * extra work in their equivalent of fget() - they insert struct + * file immediately after grabbing descriptor, mark it larval if + * more work (e.g. actual opening) is needed and make sure that + * fget() treats larval files as absent. Potentially interesting, + * but while extra work in fget() is trivial, locking implications + * and amount of surgery on open()-related paths in VFS are not. + * FreeBSD fails with -EBADF in the same situation, NetBSD "solution" + * deadlocks in rather amusing ways, AFAICS. All of that is out of + * scope of POSIX or SUS, since neither considers shared descriptor + * tables and this condition does not arise without those. + */ + err = -EBUSY; + fdt = files_fdtable(files); + tofree = fdt->fd[newfd]; + if (!tofree && fd_is_open(newfd, fdt)) + goto out_unlock; + get_file(file); + rcu_assign_pointer(fdt->fd[newfd], file); + __set_open_fd(newfd, fdt); + if (flags & O_CLOEXEC) + __set_close_on_exec(newfd, fdt); + else + __clear_close_on_exec(newfd, fdt); + spin_unlock(&files->file_lock); + + if (tofree) + filp_close(tofree, files); + + return newfd; + +Ebadf: + err = -EBADF; +out_unlock: + spin_unlock(&files->file_lock); + return err; +} + +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)) + retval = -EBADF; + rcu_read_unlock(); + return retval; + } + return sys_dup3(oldfd, newfd, 0); +} + +SYSCALL_DEFINE1(dup, unsigned int, fildes) +{ + int ret = -EBADF; + struct file *file = fget_raw(fildes); + + if (file) { + ret = get_unused_fd(); + if (ret >= 0) + fd_install(ret, file); + else + fput(file); + } + return ret; +} + +int f_dupfd(unsigned int from, struct file *file, unsigned flags) +{ + int err; + if (from >= rlimit(RLIMIT_NOFILE)) + return -EINVAL; + err = alloc_fd(from, flags); + if (err >= 0) { + get_file(file); + fd_install(err, file); + } + return err; +} diff --git a/include/linux/file.h b/include/linux/file.h index 86795ec..da84fa0 100644 --- a/include/linux/file.h +++ b/include/linux/file.h @@ -30,7 +30,9 @@ extern struct file *fget(unsigned int fd); extern struct file *fget_light(unsigned int fd, int *fput_needed); extern struct file *fget_raw(unsigned int fd); extern struct file *fget_raw_light(unsigned int fd, int *fput_needed); +extern int f_dupfd(unsigned int from, struct file *file, unsigned flags); extern void set_close_on_exec(unsigned int fd, int flag); +extern bool get_close_on_exec(unsigned int fd); extern void put_filp(struct file *); extern int alloc_fd(unsigned start, unsigned flags); extern int get_unused_fd_flags(unsigned flags); |
