From 0226f4923f6c9b40cfa1c1c1b19a6ac6b3924ead Mon Sep 17 00:00:00 2001 From: Al Viro Date: Tue, 6 Dec 2011 12:21:54 -0500 Subject: vfs: take /proc/*/mounts and friends to fs/proc_namespace.c rationale: that stuff is far tighter bound to fs/namespace.c than to the guts of procfs proper. Signed-off-by: Al Viro --- fs/proc_namespace.c | 331 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 331 insertions(+) create mode 100644 fs/proc_namespace.c (limited to 'fs/proc_namespace.c') diff --git a/fs/proc_namespace.c b/fs/proc_namespace.c new file mode 100644 index 000000000000..9dcd9543ca12 --- /dev/null +++ b/fs/proc_namespace.c @@ -0,0 +1,331 @@ +/* + * fs/proc_namespace.c - handling of /proc//{mounts,mountinfo,mountstats} + * + * In fact, that's a piece of procfs; it's *almost* isolated from + * the rest of fs/proc, but has rather close relationships with + * fs/namespace.c, thus here instead of fs/proc + * + */ +#include +#include +#include +#include +#include "proc/internal.h" /* only for get_proc_task() in ->open() */ + +#include "pnode.h" +#include "internal.h" + +static unsigned mounts_poll(struct file *file, poll_table *wait) +{ + struct proc_mounts *p = file->private_data; + struct mnt_namespace *ns = p->ns; + unsigned res = POLLIN | POLLRDNORM; + + poll_wait(file, &p->ns->poll, wait); + + br_read_lock(vfsmount_lock); + if (p->m.poll_event != ns->event) { + p->m.poll_event = ns->event; + res |= POLLERR | POLLPRI; + } + br_read_unlock(vfsmount_lock); + + return res; +} + +struct proc_fs_info { + int flag; + const char *str; +}; + +static int show_sb_opts(struct seq_file *m, struct super_block *sb) +{ + static const struct proc_fs_info fs_info[] = { + { MS_SYNCHRONOUS, ",sync" }, + { MS_DIRSYNC, ",dirsync" }, + { MS_MANDLOCK, ",mand" }, + { 0, NULL } + }; + const struct proc_fs_info *fs_infop; + + for (fs_infop = fs_info; fs_infop->flag; fs_infop++) { + if (sb->s_flags & fs_infop->flag) + seq_puts(m, fs_infop->str); + } + + return security_sb_show_options(m, sb); +} + +static void show_mnt_opts(struct seq_file *m, struct vfsmount *mnt) +{ + static const struct proc_fs_info mnt_info[] = { + { MNT_NOSUID, ",nosuid" }, + { MNT_NODEV, ",nodev" }, + { MNT_NOEXEC, ",noexec" }, + { MNT_NOATIME, ",noatime" }, + { MNT_NODIRATIME, ",nodiratime" }, + { MNT_RELATIME, ",relatime" }, + { 0, NULL } + }; + const struct proc_fs_info *fs_infop; + + for (fs_infop = mnt_info; fs_infop->flag; fs_infop++) { + if (mnt->mnt_flags & fs_infop->flag) + seq_puts(m, fs_infop->str); + } +} + +static inline void mangle(struct seq_file *m, const char *s) +{ + seq_escape(m, s, " \t\n\\"); +} + +static void show_type(struct seq_file *m, struct super_block *sb) +{ + mangle(m, sb->s_type->name); + if (sb->s_subtype && sb->s_subtype[0]) { + seq_putc(m, '.'); + mangle(m, sb->s_subtype); + } +} + +static int show_vfsmnt(struct seq_file *m, struct vfsmount *mnt) +{ + struct mount *r = real_mount(mnt); + int err = 0; + struct path mnt_path = { .dentry = mnt->mnt_root, .mnt = mnt }; + + if (mnt->mnt_sb->s_op->show_devname) { + err = mnt->mnt_sb->s_op->show_devname(m, mnt); + if (err) + goto out; + } else { + mangle(m, r->mnt_devname ? r->mnt_devname : "none"); + } + seq_putc(m, ' '); + seq_path(m, &mnt_path, " \t\n\\"); + seq_putc(m, ' '); + show_type(m, mnt->mnt_sb); + seq_puts(m, __mnt_is_readonly(mnt) ? " ro" : " rw"); + err = show_sb_opts(m, mnt->mnt_sb); + if (err) + goto out; + show_mnt_opts(m, mnt); + if (mnt->mnt_sb->s_op->show_options) + err = mnt->mnt_sb->s_op->show_options(m, mnt); + seq_puts(m, " 0 0\n"); +out: + return err; +} + +static int show_mountinfo(struct seq_file *m, struct vfsmount *mnt) +{ + struct proc_mounts *p = m->private; + struct mount *r = real_mount(mnt); + struct super_block *sb = mnt->mnt_sb; + struct path mnt_path = { .dentry = mnt->mnt_root, .mnt = mnt }; + struct path root = p->root; + int err = 0; + + seq_printf(m, "%i %i %u:%u ", r->mnt_id, r->mnt_parent->mnt_id, + MAJOR(sb->s_dev), MINOR(sb->s_dev)); + if (sb->s_op->show_path) + err = sb->s_op->show_path(m, mnt); + else + seq_dentry(m, mnt->mnt_root, " \t\n\\"); + if (err) + goto out; + seq_putc(m, ' '); + + /* mountpoints outside of chroot jail will give SEQ_SKIP on this */ + err = seq_path_root(m, &mnt_path, &root, " \t\n\\"); + if (err) + goto out; + + seq_puts(m, mnt->mnt_flags & MNT_READONLY ? " ro" : " rw"); + show_mnt_opts(m, mnt); + + /* Tagged fields ("foo:X" or "bar") */ + if (IS_MNT_SHARED(r)) + seq_printf(m, " shared:%i", r->mnt_group_id); + if (IS_MNT_SLAVE(r)) { + int master = r->mnt_master->mnt_group_id; + int dom = get_dominating_id(r, &p->root); + seq_printf(m, " master:%i", master); + if (dom && dom != master) + seq_printf(m, " propagate_from:%i", dom); + } + if (IS_MNT_UNBINDABLE(r)) + seq_puts(m, " unbindable"); + + /* Filesystem specific data */ + seq_puts(m, " - "); + show_type(m, sb); + seq_putc(m, ' '); + if (sb->s_op->show_devname) + err = sb->s_op->show_devname(m, mnt); + else + mangle(m, r->mnt_devname ? r->mnt_devname : "none"); + if (err) + goto out; + seq_puts(m, sb->s_flags & MS_RDONLY ? " ro" : " rw"); + err = show_sb_opts(m, sb); + if (err) + goto out; + if (sb->s_op->show_options) + err = sb->s_op->show_options(m, mnt); + seq_putc(m, '\n'); +out: + return err; +} + +static int show_vfsstat(struct seq_file *m, struct vfsmount *mnt) +{ + struct mount *r = real_mount(mnt); + struct path mnt_path = { .dentry = mnt->mnt_root, .mnt = mnt }; + int err = 0; + + /* device */ + if (mnt->mnt_sb->s_op->show_devname) { + seq_puts(m, "device "); + err = mnt->mnt_sb->s_op->show_devname(m, mnt); + } else { + if (r->mnt_devname) { + seq_puts(m, "device "); + mangle(m, r->mnt_devname); + } else + seq_puts(m, "no device"); + } + + /* mount point */ + seq_puts(m, " mounted on "); + seq_path(m, &mnt_path, " \t\n\\"); + seq_putc(m, ' '); + + /* file system type */ + seq_puts(m, "with fstype "); + show_type(m, mnt->mnt_sb); + + /* optional statistics */ + if (mnt->mnt_sb->s_op->show_stats) { + seq_putc(m, ' '); + if (!err) + err = mnt->mnt_sb->s_op->show_stats(m, mnt); + } + + seq_putc(m, '\n'); + return err; +} + +static int mounts_open_common(struct inode *inode, struct file *file, + int (*show)(struct seq_file *, struct vfsmount *)) +{ + struct task_struct *task = get_proc_task(inode); + struct nsproxy *nsp; + struct mnt_namespace *ns = NULL; + struct path root; + struct proc_mounts *p; + int ret = -EINVAL; + + if (!task) + goto err; + + rcu_read_lock(); + nsp = task_nsproxy(task); + if (!nsp) { + rcu_read_unlock(); + put_task_struct(task); + goto err; + } + ns = nsp->mnt_ns; + if (!ns) { + rcu_read_unlock(); + put_task_struct(task); + goto err; + } + get_mnt_ns(ns); + rcu_read_unlock(); + task_lock(task); + if (!task->fs) { + task_unlock(task); + put_task_struct(task); + ret = -ENOENT; + goto err_put_ns; + } + get_fs_root(task->fs, &root); + task_unlock(task); + put_task_struct(task); + + ret = -ENOMEM; + p = kmalloc(sizeof(struct proc_mounts), GFP_KERNEL); + if (!p) + goto err_put_path; + + file->private_data = &p->m; + ret = seq_open(file, &mounts_op); + if (ret) + goto err_free; + + p->m.private = p; + p->ns = ns; + p->root = root; + p->m.poll_event = ns->event; + p->show = show; + + return 0; + + err_free: + kfree(p); + err_put_path: + path_put(&root); + err_put_ns: + put_mnt_ns(ns); + err: + return ret; +} + +static int mounts_release(struct inode *inode, struct file *file) +{ + struct proc_mounts *p = file->private_data; + path_put(&p->root); + put_mnt_ns(p->ns); + return seq_release(inode, file); +} + +static int mounts_open(struct inode *inode, struct file *file) +{ + return mounts_open_common(inode, file, show_vfsmnt); +} + +static int mountinfo_open(struct inode *inode, struct file *file) +{ + return mounts_open_common(inode, file, show_mountinfo); +} + +static int mountstats_open(struct inode *inode, struct file *file) +{ + return mounts_open_common(inode, file, show_vfsstat); +} + +const struct file_operations proc_mounts_operations = { + .open = mounts_open, + .read = seq_read, + .llseek = seq_lseek, + .release = mounts_release, + .poll = mounts_poll, +}; + +const struct file_operations proc_mountinfo_operations = { + .open = mountinfo_open, + .read = seq_read, + .llseek = seq_lseek, + .release = mounts_release, + .poll = mounts_poll, +}; + +const struct file_operations proc_mountstats_operations = { + .open = mountstats_open, + .read = seq_read, + .llseek = seq_lseek, + .release = mounts_release, +}; -- cgit v1.2.3-59-g8ed1b