diff options
Diffstat (limited to 'fs/file.c')
| -rw-r--r-- | fs/file.c | 45 |
1 files changed, 45 insertions, 0 deletions
diff --git a/fs/file.c b/fs/file.c index abb8b7081d7a..0cd598cab476 100644 --- a/fs/file.c +++ b/fs/file.c @@ -18,6 +18,7 @@ #include <linux/bitops.h> #include <linux/spinlock.h> #include <linux/rcupdate.h> +#include <net/sock.h> unsigned int sysctl_nr_open __read_mostly = 1024*1024; unsigned int sysctl_nr_open_min = BITS_PER_LONG; @@ -613,6 +614,10 @@ void __fd_install(struct files_struct *files, unsigned int fd, rcu_read_unlock_sched(); } +/* + * This consumes the "file" refcount, so callers should treat it + * as if they had called fput(file). + */ void fd_install(unsigned int fd, struct file *file) { __fd_install(current->files, fd, file); @@ -931,6 +936,46 @@ out_unlock: return err; } +/** + * __receive_fd() - Install received file into file descriptor table + * + * @file: struct file that was received from another process + * @ufd: __user pointer to write new fd number to + * @o_flags: the O_* flags to apply to the new fd entry + * + * Installs a received file into the file descriptor table, with appropriate + * checks and count updates. Writes the fd number to userspace. + * + * This helper handles its own reference counting of the incoming + * struct file. + * + * Returns -ve on error. + */ +int __receive_fd(struct file *file, int __user *ufd, unsigned int o_flags) +{ + int new_fd; + int error; + + error = security_file_receive(file); + if (error) + return error; + + new_fd = get_unused_fd_flags(o_flags); + if (new_fd < 0) + return new_fd; + + error = put_user(new_fd, ufd); + if (error) { + put_unused_fd(new_fd); + return error; + } + + /* Bump the sock usage counts, if any. */ + __receive_sock(file); + fd_install(new_fd, get_file(file)); + return 0; +} + static int ksys_dup3(unsigned int oldfd, unsigned int newfd, int flags) { int err = -EBADF; |