cregit-Linux how code gets into the kernel

Release 4.7 fs/proc/root.c

Directory: fs/proc
/*
 *  linux/fs/proc/root.c
 *
 *  Copyright (C) 1991, 1992 Linus Torvalds
 *
 *  proc root directory handling functions
 */

#include <asm/uaccess.h>

#include <linux/errno.h>
#include <linux/time.h>
#include <linux/proc_fs.h>
#include <linux/stat.h>
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/module.h>
#include <linux/bitops.h>
#include <linux/user_namespace.h>
#include <linux/mount.h>
#include <linux/pid_namespace.h>
#include <linux/parser.h>

#include "internal.h"




static int proc_test_super(struct super_block *sb, void *data)
{
	return sb->s_fs_info == data;
}


Contributors
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pavel emelianovpavel emelianov22100.00%1100.00%


Total22100.00%1100.00%






static int proc_set_super(struct super_block *sb, void *data)
{
	int err = set_anon_super(sb, NULL);
	if (!err) {
		struct pid_namespace *ns = (struct pid_namespace *)data;
		sb->s_fs_info = get_pid_ns(ns);
	}
	return err;
}


Contributors
PersonTokensPropCommitsCommitProp
pavel emelianovpavel emelianov3664.29%150.00%


al viroal viro2035.71%150.00%


Total56100.00%2100.00%



enum {
	


Opt_gid, Opt_hidepid, Opt_err,
};


static const match_table_t tokens = {
	{Opt_hidepid, "hidepid=%u"},
	{Opt_gid, "gid=%u"},
	{Opt_err, NULL},
};




static int proc_parse_options(char *options, struct pid_namespace *pid)
{
	char *p;
	substring_t args[MAX_OPT_ARGS];
	int option;

	if (!options)
		return 1;

	while ((p = strsep(&options, ",")) != NULL) {
		int token;
		if (!*p)
			continue;

		args[0].to = args[0].from = NULL;
		token = match_token(p, tokens, args);
		switch (token) {
		case Opt_gid:
			if (match_int(&args[0], &option))
				return 0;
			pid->pid_gid = make_kgid(current_user_ns(), option);
			break;
		case Opt_hidepid:
			if (match_int(&args[0], &option))
				return 0;
			if (option < 0 || option > 2) {
				pr_err("proc: hidepid value must be between 0 and 2.\n");
				return 0;
			}
			pid->hide_pid = option;
			break;
		default:
			pr_err("proc: unrecognized mount option \"%s\" "
			       "or missing value\n", p);
			return 0;
		}
	}

	return 1;
}


Contributors
PersonTokensPropCommitsCommitProp
vasiliy kulikovvasiliy kulikov18596.35%250.00%


eric w. biedermaneric w. biederman63.12%125.00%


sachin kamatsachin kamat10.52%125.00%


Total192100.00%4100.00%






int proc_remount(struct super_block *sb, int *flags, char *data)
{
	struct pid_namespace *pid = sb->s_fs_info;

	sync_filesystem(sb);
	return !proc_parse_options(data, pid);
}


Contributors
PersonTokensPropCommitsCommitProp
vasiliy kulikovvasiliy kulikov3687.80%150.00%


theodore tsotheodore tso512.20%150.00%


Total41100.00%2100.00%






static struct dentry *proc_mount(struct file_system_type *fs_type,
	int flags, const char *dev_name, void *data)
{
	int err;
	struct super_block *sb;
	struct pid_namespace *ns;
	char *options;

	if (flags & MS_KERNMOUNT) {
		ns = (struct pid_namespace *)data;
		options = NULL;
	} else {
		ns = task_active_pid_ns(current);
		options = data;

		/* Does the mounter have privilege over the pid namespace? */
		if (!ns_capable(ns->user_ns, CAP_SYS_ADMIN))
			return ERR_PTR(-EPERM);
	}

	sb = sget(fs_type, proc_test_super, proc_set_super, flags, ns);
	if (IS_ERR(sb))
		return ERR_CAST(sb);

	/*
         * procfs isn't actually a stacking filesystem; however, there is
         * too much magic going on inside it to permit stacking things on
         * top of it
         */
	sb->s_stack_depth = FILESYSTEM_MAX_STACK_DEPTH;

	if (!proc_parse_options(options, ns)) {
		deactivate_locked_super(sb);
		return ERR_PTR(-EINVAL);
	}

	if (!sb->s_root) {
		err = proc_fill_super(sb);
		if (err) {
			deactivate_locked_super(sb);
			return ERR_PTR(err);
		}

		sb->s_flags |= MS_ACTIVE;
		/* User space would break if executables appear on proc */
		sb->s_iflags |= SB_I_NOEXEC;
	}

	return dget(sb->s_root);
}


Contributors
PersonTokensPropCommitsCommitProp
pavel emelianovpavel emelianov7535.71%15.88%


vasiliy kulikovvasiliy kulikov4521.43%211.76%


eric w. biedermaneric w. biederman3918.57%741.18%


al viroal viro3516.67%317.65%


jann hornjann horn73.33%15.88%


linus torvaldslinus torvalds62.86%15.88%


david howellsdavid howells20.95%15.88%


andries brouwerandries brouwer10.48%15.88%


Total210100.00%17100.00%






static void proc_kill_sb(struct super_block *sb)
{
	struct pid_namespace *ns;

	ns = (struct pid_namespace *)sb->s_fs_info;
	if (ns->proc_self)
		dput(ns->proc_self);
	if (ns->proc_thread_self)
		dput(ns->proc_thread_self);
	kill_anon_super(sb);
	put_pid_ns(ns);
}


Contributors
PersonTokensPropCommitsCommitProp
pavel emelianovpavel emelianov3758.73%133.33%


eric w. biedermaneric w. biederman1320.63%133.33%


al viroal viro1320.63%133.33%


Total63100.00%3100.00%




static struct file_system_type proc_fs_type = {
	.name		= "proc",
	.mount		= proc_mount,
	.kill_sb	= proc_kill_sb,
	.fs_flags	= FS_USERNS_VISIBLE | FS_USERNS_MOUNT,
};




void __init proc_root_init(void)
{
	int err;

	proc_init_inodecache();
	err = register_filesystem(&proc_fs_type);
	if (err)
		return;

	proc_self_init();
	proc_thread_self_init();
	proc_symlink("mounts", NULL, "self/mounts");

	proc_net_init();

#ifdef CONFIG_SYSVIPC
	proc_mkdir("sysvipc", NULL);
#endif
	proc_mkdir("fs", NULL);
	proc_mkdir("driver", NULL);
	proc_create_mount_point("fs/nfsd"); /* somewhere for the nfsd filesystem to be mounted */
#if defined(CONFIG_SUN_OPENPROMFS) || defined(CONFIG_SUN_OPENPROMFS_MODULE)
	/* just give it a mountpoint */
	proc_create_mount_point("openprom");
#endif
	proc_tty_init();
	proc_mkdir("bus", NULL);
	proc_sys_init();
}


Contributors
PersonTokensPropCommitsCommitProp
pre-gitpre-git5954.13%1145.83%


linus torvaldslinus torvalds1311.93%28.33%


eric w. biedermaneric w. biederman1311.93%520.83%


alexey dobriyanalexey dobriyan98.26%28.33%


neil brownneil brown54.59%14.17%


al viroal viro54.59%14.17%


mika kukkonenmika kukkonen43.67%14.17%


harald welteharald welte10.92%14.17%


Total109100.00%24100.00%






static int proc_root_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat
)
{
	generic_fillattr(d_inode(dentry), stat);
	stat->nlink = proc_root.nlink + nr_processes();
	return 0;
}


Contributors
PersonTokensPropCommitsCommitProp
al viroal viro4293.33%150.00%


david howellsdavid howells36.67%150.00%


Total45100.00%2100.00%






static struct dentry *proc_root_lookup(struct inode * dir, struct dentry * dentry, unsigned int flags)
{
	if (!proc_pid_lookup(dir, dentry, flags))
		return NULL;
	
	return proc_lookup(dir, dentry, flags);
}


Contributors
PersonTokensPropCommitsCommitProp
pre-gitpre-git3778.72%666.67%


al viroal viro510.64%111.11%


trond myklebusttrond myklebust36.38%111.11%


alexey dobriyanalexey dobriyan24.26%111.11%


Total47100.00%9100.00%






static int proc_root_readdir(struct file *file, struct dir_context *ctx)
{
	if (ctx->pos < FIRST_PROCESS_ENTRY) {
		int error = proc_readdir(file, ctx);
		if (unlikely(error <= 0))
			return error;
		ctx->pos = FIRST_PROCESS_ENTRY;
	}

	return proc_pid_readdir(file, ctx);
}


Contributors
PersonTokensPropCommitsCommitProp
pre-gitpre-git3251.61%777.78%


richard genoudrichard genoud1625.81%111.11%


al viroal viro1422.58%111.11%


Total62100.00%9100.00%



/*
 * The root /proc directory is special, as it has the
 * <pid> directories. Thus we don't use the generic
 * directory handling functions for that..
 */

static const struct file_operations proc_root_operations = {
	.read		 = generic_read_dir,
	.iterate_shared	 = proc_root_readdir,
	.llseek		= generic_file_llseek,
};

/*
 * proc root can do almost nothing..
 */

static const struct inode_operations proc_root_inode_operations = {
	.lookup		= proc_root_lookup,
	.getattr	= proc_root_getattr,
};

/*
 * This is the root "inode" in the /proc tree..
 */

struct proc_dir_entry proc_root = {
	.low_ino	= PROC_ROOT_INO, 
	.namelen	= 5, 
	.mode		= S_IFDIR | S_IRUGO | S_IXUGO, 
	.nlink		= 2, 
	.count		= ATOMIC_INIT(1),
	.proc_iops	= &proc_root_inode_operations, 
	.proc_fops	= &proc_root_operations,
	.parent		= &proc_root,
	.subdir		= RB_ROOT,
	.name		= "/proc",
};




int pid_ns_prepare_proc(struct pid_namespace *ns)
{
	struct vfsmount *mnt;

	mnt = kern_mount_data(&proc_fs_type, ns);
	if (IS_ERR(mnt))
		return PTR_ERR(mnt);

	ns->proc_mnt = mnt;
	return 0;
}


Contributors
PersonTokensPropCommitsCommitProp
pavel emelianovpavel emelianov4187.23%150.00%


al viroal viro612.77%150.00%


Total47100.00%2100.00%






void pid_ns_release_proc(struct pid_namespace *ns)
{
	kern_unmount(ns->proc_mnt);
}

Contributors
PersonTokensPropCommitsCommitProp
pavel emelianovpavel emelianov1694.12%150.00%


al viroal viro15.88%150.00%


Total17100.00%2100.00%




Overall Contributors
PersonTokensPropCommitsCommitProp
vasiliy kulikovvasiliy kulikov30326.89%33.49%


pavel emelianovpavel emelianov23120.50%22.33%


pre-gitpre-git20718.37%2427.91%


al viroal viro16714.82%1517.44%


eric w. biedermaneric w. biederman847.45%1517.44%


art haasart haas262.31%11.16%


linus torvaldslinus torvalds221.95%22.33%


alexey dobriyanalexey dobriyan201.77%55.81%


richard genoudrichard genoud161.42%11.16%


david howellsdavid howells100.89%33.49%


jann hornjann horn70.62%11.16%


neil brownneil brown50.44%11.16%


theodore tsotheodore tso50.44%11.16%


nicolas dichtelnicolas dichtel50.44%11.16%


mika kukkonenmika kukkonen40.35%11.16%


arnd bergmannarnd bergmann40.35%11.16%


trond myklebusttrond myklebust30.27%11.16%


arjan van de venarjan van de ven20.18%22.33%


adrian bunkadrian bunk20.18%22.33%


andries brouwerandries brouwer10.09%11.16%


harald welteharald welte10.09%11.16%


dave jonesdave jones10.09%11.16%


sachin kamatsachin kamat10.09%11.16%


Total1127100.00%86100.00%

  
Directory: fs/proc



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