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procfs: Use the proc generic infrastructure for proc/self.
I had visions at one point of splitting proc into two filesystems. If that had happened proc/self being the the part of proc that actually deals with pids would have been a nice cleanup. As it is proc/self requires a lot of unnecessary infrastructure for a single file. The only user visible change is that a mounted /proc for a pid namespace that is dead now shows a broken proc symlink, instead of being completely invisible. I don't think anyone will notice or care. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
This commit is contained in:
Eric W. Biederman
parent
dd34ad35c3
commit
e656d8a6f7
@ -21,6 +21,7 @@ proc-y += uptime.o
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proc-y += version.o
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proc-y += softirqs.o
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proc-y += namespaces.o
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proc-y += self.o
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proc-$(CONFIG_PROC_SYSCTL) += proc_sysctl.o
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proc-$(CONFIG_NET) += proc_net.o
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proc-$(CONFIG_PROC_KCORE) += kcore.o
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154
fs/proc/base.c
154
fs/proc/base.c
@ -2237,146 +2237,6 @@ static const struct file_operations proc_coredump_filter_operations = {
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};
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#endif
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/*
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* /proc/self:
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*/
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static int proc_self_readlink(struct dentry *dentry, char __user *buffer,
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int buflen)
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{
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struct pid_namespace *ns = dentry->d_sb->s_fs_info;
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pid_t tgid = task_tgid_nr_ns(current, ns);
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char tmp[PROC_NUMBUF];
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if (!tgid)
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return -ENOENT;
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sprintf(tmp, "%d", tgid);
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return vfs_readlink(dentry,buffer,buflen,tmp);
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}
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static void *proc_self_follow_link(struct dentry *dentry, struct nameidata *nd)
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{
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struct pid_namespace *ns = dentry->d_sb->s_fs_info;
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pid_t tgid = task_tgid_nr_ns(current, ns);
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char *name = ERR_PTR(-ENOENT);
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if (tgid) {
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/* 11 for max length of signed int in decimal + NULL term */
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name = kmalloc(12, GFP_KERNEL);
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if (!name)
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name = ERR_PTR(-ENOMEM);
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else
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sprintf(name, "%d", tgid);
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}
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nd_set_link(nd, name);
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return NULL;
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}
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static void proc_self_put_link(struct dentry *dentry, struct nameidata *nd,
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void *cookie)
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{
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char *s = nd_get_link(nd);
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if (!IS_ERR(s))
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kfree(s);
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}
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static const struct inode_operations proc_self_inode_operations = {
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.readlink = proc_self_readlink,
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.follow_link = proc_self_follow_link,
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.put_link = proc_self_put_link,
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};
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/*
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* proc base
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*
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* These are the directory entries in the root directory of /proc
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* that properly belong to the /proc filesystem, as they describe
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* describe something that is process related.
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*/
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static const struct pid_entry proc_base_stuff[] = {
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NOD("self", S_IFLNK|S_IRWXUGO,
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&proc_self_inode_operations, NULL, {}),
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};
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static struct dentry *proc_base_instantiate(struct inode *dir,
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struct dentry *dentry, struct task_struct *task, const void *ptr)
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{
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const struct pid_entry *p = ptr;
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struct inode *inode;
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struct proc_inode *ei;
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struct dentry *error;
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/* Allocate the inode */
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error = ERR_PTR(-ENOMEM);
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inode = new_inode(dir->i_sb);
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if (!inode)
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goto out;
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/* Initialize the inode */
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ei = PROC_I(inode);
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inode->i_ino = get_next_ino();
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inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
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/*
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* grab the reference to the task.
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*/
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ei->pid = get_task_pid(task, PIDTYPE_PID);
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if (!ei->pid)
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goto out_iput;
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inode->i_mode = p->mode;
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if (S_ISDIR(inode->i_mode))
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set_nlink(inode, 2);
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if (S_ISLNK(inode->i_mode))
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inode->i_size = 64;
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if (p->iop)
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inode->i_op = p->iop;
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if (p->fop)
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inode->i_fop = p->fop;
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ei->op = p->op;
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d_add(dentry, inode);
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error = NULL;
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out:
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return error;
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out_iput:
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iput(inode);
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goto out;
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}
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static struct dentry *proc_base_lookup(struct inode *dir, struct dentry *dentry)
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{
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struct dentry *error;
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struct task_struct *task = get_proc_task(dir);
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const struct pid_entry *p, *last;
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error = ERR_PTR(-ENOENT);
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if (!task)
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goto out_no_task;
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/* Lookup the directory entry */
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last = &proc_base_stuff[ARRAY_SIZE(proc_base_stuff) - 1];
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for (p = proc_base_stuff; p <= last; p++) {
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if (p->len != dentry->d_name.len)
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continue;
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if (!memcmp(dentry->d_name.name, p->name, p->len))
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break;
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}
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if (p > last)
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goto out;
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error = proc_base_instantiate(dir, dentry, task, p);
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out:
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put_task_struct(task);
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out_no_task:
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return error;
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}
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static int proc_base_fill_cache(struct file *filp, void *dirent,
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filldir_t filldir, struct task_struct *task, const struct pid_entry *p)
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{
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return proc_fill_cache(filp, dirent, filldir, p->name, p->len,
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proc_base_instantiate, task, p);
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}
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#ifdef CONFIG_TASK_IO_ACCOUNTING
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static int do_io_accounting(struct task_struct *task, char *buffer, int whole)
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{
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@ -2767,15 +2627,11 @@ out:
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struct dentry *proc_pid_lookup(struct inode *dir, struct dentry * dentry, unsigned int flags)
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{
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struct dentry *result;
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struct dentry *result = NULL;
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struct task_struct *task;
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unsigned tgid;
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struct pid_namespace *ns;
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result = proc_base_lookup(dir, dentry);
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if (!IS_ERR(result) || PTR_ERR(result) != -ENOENT)
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goto out;
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tgid = name_to_int(dentry);
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if (tgid == ~0U)
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goto out;
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@ -2838,7 +2694,7 @@ retry:
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return iter;
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}
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#define TGID_OFFSET (FIRST_PROCESS_ENTRY + ARRAY_SIZE(proc_base_stuff))
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#define TGID_OFFSET (FIRST_PROCESS_ENTRY)
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static int proc_pid_fill_cache(struct file *filp, void *dirent, filldir_t filldir,
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struct tgid_iter iter)
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@ -2872,12 +2728,6 @@ int proc_pid_readdir(struct file * filp, void * dirent, filldir_t filldir)
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if (!reaper)
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goto out_no_task;
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for (; nr < ARRAY_SIZE(proc_base_stuff); filp->f_pos++, nr++) {
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const struct pid_entry *p = &proc_base_stuff[nr];
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if (proc_base_fill_cache(filp, dirent, filldir, reaper, p) < 0)
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goto out;
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}
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ns = filp->f_dentry->d_sb->s_fs_info;
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iter.task = NULL;
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iter.tgid = filp->f_pos - TGID_OFFSET;
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@ -15,6 +15,7 @@ struct ctl_table_header;
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struct mempolicy;
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extern struct proc_dir_entry proc_root;
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extern void proc_self_init(void);
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#ifdef CONFIG_PROC_SYSCTL
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extern int proc_sys_init(void);
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extern void sysctl_head_put(struct ctl_table_header *head);
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@ -169,6 +169,7 @@ void __init proc_root_init(void)
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return;
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}
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proc_self_init();
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proc_symlink("mounts", NULL, "self/mounts");
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proc_net_init();
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59
fs/proc/self.c
Normal file
59
fs/proc/self.c
Normal file
@ -0,0 +1,59 @@
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#include <linux/proc_fs.h>
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#include <linux/sched.h>
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#include <linux/namei.h>
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/*
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* /proc/self:
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*/
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static int proc_self_readlink(struct dentry *dentry, char __user *buffer,
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int buflen)
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{
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struct pid_namespace *ns = dentry->d_sb->s_fs_info;
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pid_t tgid = task_tgid_nr_ns(current, ns);
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char tmp[PROC_NUMBUF];
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if (!tgid)
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return -ENOENT;
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sprintf(tmp, "%d", tgid);
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return vfs_readlink(dentry,buffer,buflen,tmp);
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}
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static void *proc_self_follow_link(struct dentry *dentry, struct nameidata *nd)
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{
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struct pid_namespace *ns = dentry->d_sb->s_fs_info;
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pid_t tgid = task_tgid_nr_ns(current, ns);
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char *name = ERR_PTR(-ENOENT);
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if (tgid) {
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/* 11 for max length of signed int in decimal + NULL term */
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name = kmalloc(12, GFP_KERNEL);
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if (!name)
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name = ERR_PTR(-ENOMEM);
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else
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sprintf(name, "%d", tgid);
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}
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nd_set_link(nd, name);
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return NULL;
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}
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static void proc_self_put_link(struct dentry *dentry, struct nameidata *nd,
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void *cookie)
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{
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char *s = nd_get_link(nd);
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if (!IS_ERR(s))
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kfree(s);
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}
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static const struct inode_operations proc_self_inode_operations = {
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.readlink = proc_self_readlink,
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.follow_link = proc_self_follow_link,
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.put_link = proc_self_put_link,
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};
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void __init proc_self_init(void)
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{
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struct proc_dir_entry *proc_self_symlink;
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mode_t mode;
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mode = S_IFLNK | S_IRWXUGO;
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proc_self_symlink = proc_create("self", mode, NULL, NULL );
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proc_self_symlink->proc_iops = &proc_self_inode_operations;
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}
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