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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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#include <linux/proc_fs.h>
#include "../mount.h"#include "internal.h"#include "fd.h"
static int seq_show(struct seq_file *m, void *v){ struct files_struct *files = NULL; int f_flags = 0, ret = -ENOENT; struct file *file = NULL; struct task_struct *task;
task = get_proc_task(m->private); if (!task) return -ENOENT;
task_lock(task); files = task->files; if (files) { unsigned int fd = proc_fd(m->private);
spin_lock(&files->file_lock); file = files_lookup_fd_locked(files, fd); if (file) { f_flags = file->f_flags; if (close_on_exec(fd, files)) f_flags |= O_CLOEXEC;
get_file(file); ret = 0; } spin_unlock(&files->file_lock); } task_unlock(task); put_task_struct(task);
if (ret) return ret;
seq_printf(m, "pos:\t%lli\nflags:\t0%o\nmnt_id:\t%i\nino:\t%llu\n", (long long)file->f_pos, f_flags, real_mount(file->f_path.mnt)->mnt_id, file_inode(file)->i_ino);
/* show_fd_locks() never dereferences files, so a stale value is safe */ show_fd_locks(m, file, files); if (seq_has_overflowed(m)) goto out;
if (file->f_op->show_fdinfo) file->f_op->show_fdinfo(m, file);
out: fput(file); return 0;}
static int seq_fdinfo_open(struct inode *inode, struct file *file){ return single_open(file, seq_show, inode);}
/* * Shared /proc/pid/fdinfo and /proc/pid/fdinfo/fd permission helper to ensure * that the current task has PTRACE_MODE_READ in addition to the normal * POSIX-like checks. */static int proc_fdinfo_permission(struct mnt_idmap *idmap, struct inode *inode, int mask){ bool allowed = false; struct task_struct *task = get_proc_task(inode);
if (!task) return -ESRCH;
allowed = ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS); put_task_struct(task);
if (!allowed) return -EACCES;
return generic_permission(idmap, inode, mask);}
static const struct inode_operations proc_fdinfo_file_inode_operations = { .permission = proc_fdinfo_permission, .setattr = proc_nochmod_setattr,};
static const struct file_operations proc_fdinfo_file_operations = { .open = seq_fdinfo_open, .read = seq_read, .llseek = seq_lseek, .release = single_release,};
static bool tid_fd_mode(struct task_struct *task, unsigned fd, fmode_t *mode){ struct file *file;
file = fget_task(task, fd); if (file) { *mode = file->f_mode; fput(file); } return !!file;}
static void tid_fd_update_inode(struct task_struct *task, struct inode *inode, fmode_t f_mode){ task_dump_owner(task, 0, &inode->i_uid, &inode->i_gid);
if (S_ISLNK(inode->i_mode)) { unsigned i_mode = S_IFLNK; if (f_mode & FMODE_READ) i_mode |= S_IRUSR | S_IXUSR; if (f_mode & FMODE_WRITE) i_mode |= S_IWUSR | S_IXUSR; inode->i_mode = i_mode; } security_task_to_inode(task, inode);}
static int tid_fd_revalidate(struct inode *dir, const struct qstr *name, struct dentry *dentry, unsigned int flags){ struct task_struct *task; struct inode *inode; unsigned int fd;
if (flags & LOOKUP_RCU) return -ECHILD;
inode = d_inode(dentry); task = get_proc_task(inode); fd = proc_fd(inode);
if (task) { fmode_t f_mode; if (tid_fd_mode(task, fd, &f_mode)) { tid_fd_update_inode(task, inode, f_mode); put_task_struct(task); return 1; } put_task_struct(task); } return 0;}
static const struct dentry_operations tid_fd_dentry_operations = { .d_revalidate = tid_fd_revalidate, .d_delete = pid_delete_dentry,};
static int proc_fd_link(struct dentry *dentry, struct path *path, struct task_struct *task){ int ret = -ENOENT; unsigned int fd = proc_fd(d_inode(dentry)); struct file *fd_file;
fd_file = fget_task(task, fd); if (fd_file) { *path = fd_file->f_path; path_get(&fd_file->f_path); ret = 0; fput(fd_file); }
return ret;}
struct fd_data { fmode_t mode; unsigned fd;};
static struct dentry *proc_fd_instantiate(struct dentry *dentry, struct task_struct *task, const void *ptr){ const struct fd_data *data = ptr; struct proc_inode *ei; struct inode *inode;
inode = proc_pid_make_inode(dentry->d_sb, task, S_IFLNK); if (!inode) return ERR_PTR(-ENOENT);
ei = PROC_I(inode); ei->fd = data->fd;
inode->i_op = &proc_pid_link_inode_operations; inode->i_size = 64;
ei->op.proc_get_link = proc_fd_link; tid_fd_update_inode(task, inode, data->mode);
return proc_splice_unmountable(inode, dentry, &tid_fd_dentry_operations);}
static struct dentry *proc_lookupfd_common(struct inode *dir, struct dentry *dentry, instantiate_t instantiate){ struct task_struct *task = get_proc_task(dir); struct fd_data data = {.fd = name_to_int(&dentry->d_name)}; struct dentry *result = ERR_PTR(-ENOENT);
if (!task) goto out_no_task; if (data.fd == ~0U) goto out; if (!tid_fd_mode(task, data.fd, &data.mode)) goto out;
result = instantiate(dentry, task, &data);out: put_task_struct(task);out_no_task: return result;}
static int proc_readfd_common(struct file *file, struct dir_context *ctx, instantiate_t instantiate){ struct task_struct *p = get_proc_task(file_inode(file)); unsigned int fd;
if (!p) return -ENOENT;
if (!dir_emit_dots(file, ctx)) goto out;
for (fd = ctx->pos - 2;; fd++) { struct file *f; struct fd_data data; char name[10 + 1]; unsigned int len;
f = fget_task_next(p, &fd); ctx->pos = fd + 2LL; if (!f) break; data.mode = f->f_mode; fput(f); data.fd = fd;
len = snprintf(name, sizeof(name), "%u", fd); if (!proc_fill_cache(file, ctx, name, len, instantiate, p, &data)) break; cond_resched(); }out: put_task_struct(p); return 0;}
static int proc_readfd_count(struct inode *inode, loff_t *count){ struct task_struct *p = get_proc_task(inode); struct fdtable *fdt;
if (!p) return -ENOENT;
task_lock(p); if (p->files) { rcu_read_lock();
fdt = files_fdtable(p->files); *count = bitmap_weight(fdt->open_fds, fdt->max_fds);
rcu_read_unlock(); } task_unlock(p);
put_task_struct(p);
return 0;}
static int proc_fd_iterate(struct file *file, struct dir_context *ctx){ return proc_readfd_common(file, ctx, proc_fd_instantiate);}
const struct file_operations proc_fd_operations = { .read = generic_read_dir, .iterate_shared = proc_fd_iterate, .llseek = generic_file_llseek,};
static struct dentry *proc_lookupfd(struct inode *dir, struct dentry *dentry, unsigned int flags){ return proc_lookupfd_common(dir, dentry, proc_fd_instantiate);}
/* * /proc/pid/fd needs a special permission handler so that a process can still * access /proc/self/fd after it has executed a setuid(). */int proc_fd_permission(struct mnt_idmap *idmap, struct inode *inode, int mask){ struct task_struct *p; int rv;
rv = generic_permission(&nop_mnt_idmap, inode, mask); if (rv == 0) return rv;
rcu_read_lock(); p = pid_task(proc_pid(inode), PIDTYPE_PID); if (p && same_thread_group(p, current)) rv = 0; rcu_read_unlock();
return rv;}
static int proc_fd_getattr(struct mnt_idmap *idmap, const struct path *path, struct kstat *stat, u32 request_mask, unsigned int query_flags){ struct inode *inode = d_inode(path->dentry);
generic_fillattr(&nop_mnt_idmap, request_mask, inode, stat); return proc_readfd_count(inode, &stat->size);}
const struct inode_operations proc_fd_inode_operations = { .lookup = proc_lookupfd, .permission = proc_fd_permission, .getattr = proc_fd_getattr, .setattr = proc_nochmod_setattr,};
static struct dentry *proc_fdinfo_instantiate(struct dentry *dentry, struct task_struct *task, const void *ptr){ const struct fd_data *data = ptr; struct proc_inode *ei; struct inode *inode;
inode = proc_pid_make_inode(dentry->d_sb, task, S_IFREG | S_IRUGO); if (!inode) return ERR_PTR(-ENOENT);
ei = PROC_I(inode); ei->fd = data->fd;
inode->i_op = &proc_fdinfo_file_inode_operations;
inode->i_fop = &proc_fdinfo_file_operations; tid_fd_update_inode(task, inode, 0);
return proc_splice_unmountable(inode, dentry, &tid_fd_dentry_operations);}
static struct dentry *proc_lookupfdinfo(struct inode *dir, struct dentry *dentry, unsigned int flags){ return proc_lookupfd_common(dir, dentry, proc_fdinfo_instantiate);}
static int proc_fdinfo_iterate(struct file *file, struct dir_context *ctx){ return proc_readfd_common(file, ctx, proc_fdinfo_instantiate);}
const struct inode_operations proc_fdinfo_inode_operations = { .lookup = proc_lookupfdinfo, .permission = proc_fdinfo_permission, .setattr = proc_nochmod_setattr,};
const struct file_operations proc_fdinfo_operations = { .read = generic_read_dir, .iterate_shared = proc_fdinfo_iterate, .llseek = generic_file_llseek,};