This patch converts /proc/pid/fdinfo/ handling routines to seq-file which is needed to extend seq operations and plug in auxiliary fdinfo provides from subsystems like eventfd/eventpoll/fsnotify.
Note the proc_fd_link no longer call for proc_fd_info, simply because proc_fd_info is converted to seq_fdinfo_open (which is seq-file open() prototype), moreover in further patches I need to provide two seq_fdinfo_open variants -- one with CONFIG_CHECKPOINT_RESTORE and one without this symbol. All in one -- this will look more messy then. Also, to eliminate code duplication (and Pavel's concerns) the fdinfo_open_helper function introduced which is used in both seq_fdinfo_open and proc_fd_link. Signed-off-by: Cyrill Gorcunov <gorcu...@openvz.org> CC: Al Viro <v...@zeniv.linux.org.uk> CC: Alexey Dobriyan <adobri...@gmail.com> CC: Andrew Morton <a...@linux-foundation.org> CC: Pavel Emelyanov <xe...@parallels.com> CC: James Bottomley <jbottom...@parallels.com> --- fs/proc/fd.c | 123 +++++++++++++++++++++++++++++++++++------------------------ 1 file changed, 75 insertions(+), 48 deletions(-) Index: linux-2.6.git/fs/proc/fd.c =================================================================== --- linux-2.6.git.orig/fs/proc/fd.c +++ linux-2.6.git/fs/proc/fd.c @@ -6,61 +6,104 @@ #include <linux/namei.h> #include <linux/pid.h> #include <linux/security.h> +#include <linux/file.h> +#include <linux/seq_file.h> #include <linux/proc_fs.h> #include "internal.h" #include "fd.h" -#define PROC_FDINFO_MAX 64 +struct proc_fdinfo { + loff_t f_pos; + int f_flags; +}; -static int proc_fd_info(struct inode *inode, struct path *path, char *info) +static int fdinfo_open_helper(struct inode *inode, int *f_flags, struct path *path) { - struct task_struct *task = get_proc_task(inode); struct files_struct *files = NULL; - int fd = proc_fd(inode); - struct file *file; + struct task_struct *task; + int ret = -ENOENT; + task = get_proc_task(inode); if (task) { files = get_files_struct(task); put_task_struct(task); } + if (files) { - /* - * We are not taking a ref to the file structure, so we must - * hold ->file_lock. - */ - spin_lock(&files->file_lock); - file = fcheck_files(files, fd); - if (file) { - unsigned int f_flags; - struct fdtable *fdt; - - fdt = files_fdtable(files); - f_flags = file->f_flags & ~O_CLOEXEC; - if (close_on_exec(fd, fdt)) - f_flags |= O_CLOEXEC; + int fd = proc_fd(inode); + struct file *fd_file; + spin_lock(&files->file_lock); + fd_file = fcheck_files(files, fd); + if (fd_file) { + if (f_flags) { + struct fdtable *fdt = files_fdtable(files); + + *f_flags = fd_file->f_flags & ~O_CLOEXEC; + if (close_on_exec(fd, fdt)) + *f_flags |= O_CLOEXEC; + } if (path) { - *path = file->f_path; - path_get(&file->f_path); + *path = fd_file->f_path; + path_get(&fd_file->f_path); } - if (info) - snprintf(info, PROC_FDINFO_MAX, - "pos:\t%lli\n" - "flags:\t0%o\n", - (long long) file->f_pos, - f_flags); - spin_unlock(&files->file_lock); - put_files_struct(files); - return 0; + ret = 0; } spin_unlock(&files->file_lock); put_files_struct(files); } - return -ENOENT; + + return ret; } +static int seq_show(struct seq_file *m, void *v) +{ + struct proc_fdinfo *fdinfo = m->private; + seq_printf(m, "pos:\t%lli\nflags:\t0%o\n", + (long long)fdinfo->f_pos, + fdinfo->f_flags); + return 0; +} + +static int seq_fdinfo_open(struct inode *inode, struct file *file) +{ + struct proc_fdinfo *fdinfo = NULL; + int ret = -ENOENT; + + fdinfo = kzalloc(sizeof(*fdinfo), GFP_KERNEL); + if (!fdinfo) + return -ENOMEM; + + ret = fdinfo_open_helper(inode, &fdinfo->f_flags, NULL); + if (!ret) { + ret = single_open(file, seq_show, fdinfo); + if (!ret) + fdinfo = NULL; + } + + kfree(fdinfo); + return ret; +} + +static int seq_fdinfo_release(struct inode *inode, struct file *file) +{ + struct seq_file *m = file->private_data; + struct proc_fdinfo *fdinfo = m->private; + + kfree(fdinfo); + + return single_release(inode, file); +} + +static const struct file_operations proc_fdinfo_file_operations = { + .open = seq_fdinfo_open, + .read = seq_read, + .llseek = seq_lseek, + .release = seq_fdinfo_release, +}; + static int tid_fd_revalidate(struct dentry *dentry, unsigned int flags) { struct files_struct *files; @@ -130,7 +173,7 @@ static const struct dentry_operations ti static int proc_fd_link(struct dentry *dentry, struct path *path) { - return proc_fd_info(dentry->d_inode, path, NULL); + return fdinfo_open_helper(dentry->d_inode, NULL, path); } static struct dentry * @@ -245,22 +288,6 @@ out_no_task: return retval; } -static ssize_t proc_fdinfo_read(struct file *file, char __user *buf, - size_t len, loff_t *ppos) -{ - char tmp[PROC_FDINFO_MAX]; - int err = proc_fd_info(file->f_path.dentry->d_inode, NULL, tmp); - if (!err) - err = simple_read_from_buffer(buf, len, ppos, tmp, strlen(tmp)); - return err; -} - -static const struct file_operations proc_fdinfo_file_operations = { - .open = nonseekable_open, - .read = proc_fdinfo_read, - .llseek = no_llseek, -}; - static int proc_readfd(struct file *filp, void *dirent, filldir_t filldir) { return proc_readfd_common(filp, dirent, filldir, proc_fd_instantiate); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/