/* * sysctl.c: General linux system control interface * * Begun 24 March 1995, Stephen Tweedie * Added /proc support, Dec 1995 * Added bdflush entry and intvec min/max checking, 2/23/96, Tom Dyas. * Added hooks for /proc/sys/net (minor, minor patch), 96/4/1, Mike Shaver. * Added kernel/java-{interpreter,appletviewer}, 96/5/10, Mike Shaver. * Dynamic registration fixes, Stephen Tweedie. * Added kswapd-interval, ctrl-alt-del, printk stuff, 1/8/97, Chris Horn. * Made sysctl support optional via CONFIG_SYSCTL, 1/10/97, Chris *  Horn. * Added proc_doulongvec_ms_jiffies_minmax, 09/08/99, Carlos H. Bauer. * Added proc_doulongvec_minmax, 09/08/99, Carlos H. Bauer. * Changed linked lists to use list.h instead of lists.h, 02/24/00, Bill *  Wendling. * The list_for_each() macro wasn't appropriate for the sysctl loop. *  Removed it and replaced it with older style, 03/23/00, Bill Wendling */#include <linux/config.h>#include <linux/slab.h>#include <linux/sysctl.h>#include <linux/swapctl.h>#include <linux/proc_fs.h>#include <linux/ctype.h>#include <linux/utsname.h>#include <linux/capability.h>#include <linux/smp_lock.h>#include <linux/init.h>#include <linux/sysrq.h>#include <linux/highuid.h>#include <asm/uaccess.h>#ifdef CONFIG_ROOT_NFS#include <linux/nfs_fs.h>#endif#if defined(CONFIG_SYSCTL)/* External variables not in a header file. */extern int panic_timeout;extern int C_A_D;extern int bdf_prm[], bdflush_min[], bdflush_max[];extern int sysctl_overcommit_memory;extern int sysctl_overcommit_ratio;extern int max_threads;extern atomic_t nr_queued_signals;extern int max_queued_signals;extern int sysrq_enabled;extern int core_uses_pid;extern int cad_pid;/* this is needed for the proc_dointvec_minmax for [fs_]overflow UID and GID */static int maxolduid = 65535;static int minolduid;#ifdef CONFIG_KMODextern char modprobe_path[];#endif#ifdef CONFIG_HOTPLUGextern char hotplug_path[];#endif#ifdef CONFIG_CHR_DEV_SGextern int sg_big_buff;#endif#ifdef CONFIG_SYSVIPCextern size_t shm_ctlmax;extern size_t shm_ctlall;extern int shm_ctlmni;extern int msg_ctlmax;extern int msg_ctlmnb;extern int msg_ctlmni;extern int sem_ctls[];#endif#ifdef __sparc__extern char reboot_command [];extern int stop_a_enabled;#endif#ifdef CONFIG_ARCH_S390#ifdef CONFIG_MATHEMUextern int sysctl_ieee_emulation_warnings;#endifextern int sysctl_userprocess_debug;#endif#if defined(CONFIG_PPC32) && defined(CONFIG_6xx)extern int powersave_nap;int proc_dol2crvec(ctl_table *table, int write, struct file *filp,		   void *buffer, size_t *lenp);#endif#ifdef CONFIG_BSD_PROCESS_ACCTextern int acct_parm[];#endifextern int pgt_cache_water[];static int parse_table(int *, int, void *, size_t *, void *, size_t,		       ctl_table *, void **);static int proc_doutsstring(ctl_table *table, int write, struct file *filp,		  void *buffer, size_t *lenp);static ctl_table root_table[];static struct ctl_table_header root_table_header =	{ root_table, LIST_HEAD_INIT(root_table_header.ctl_entry) };static ctl_table kern_table[];static ctl_table vm_table[];#ifdef CONFIG_NETextern ctl_table net_table[];#endifstatic ctl_table proc_table[];static ctl_table fs_table[];static ctl_table debug_table[];static ctl_table dev_table[];extern ctl_table random_table[];/* /proc declarations: */#ifdef CONFIG_PROC_FSstatic ssize_t proc_readsys(struct file *, char *, size_t, loff_t *);static ssize_t proc_writesys(struct file *, const char *, size_t, loff_t *);static int proc_sys_permission(struct inode *, int);struct file_operations proc_sys_file_operations = {	read:		proc_readsys,	write:		proc_writesys,};static struct inode_operations proc_sys_inode_operations = {	permission:	proc_sys_permission,};extern struct proc_dir_entry *proc_sys_root;static void register_proc_table(ctl_table *, struct proc_dir_entry *);static void unregister_proc_table(ctl_table *, struct proc_dir_entry *);#endif/* The default sysctl tables: */static ctl_table root_table[] = {	{CTL_KERN, "kernel", NULL, 0, 0555, kern_table},	{CTL_VM, "vm", NULL, 0, 0555, vm_table},#ifdef CONFIG_NET	{CTL_NET, "net", NULL, 0, 0555, net_table},#endif	{CTL_PROC, "proc", NULL, 0, 0555, proc_table},	{CTL_FS, "fs", NULL, 0, 0555, fs_table},	{CTL_DEBUG, "debug", NULL, 0, 0555, debug_table},        {CTL_DEV, "dev", NULL, 0, 0555, dev_table},	{0}};static ctl_table kern_table[] = {	{KERN_OSTYPE, "ostype", system_utsname.sysname, 64,	 0444, NULL, &proc_doutsstring, &sysctl_string},	{KERN_OSRELEASE, "osrelease", system_utsname.release, 64,	 0444, NULL, &proc_doutsstring, &sysctl_string},	{KERN_VERSION, "version", system_utsname.version, 64,	 0444, NULL, &proc_doutsstring, &sysctl_string},	{KERN_NODENAME, "hostname", system_utsname.nodename, 64,	 0644, NULL, &proc_doutsstring, &sysctl_string},	{KERN_DOMAINNAME, "domainname", system_utsname.domainname, 64,	 0644, NULL, &proc_doutsstring, &sysctl_string},	{KERN_PANIC, "panic", &panic_timeout, sizeof(int),	 0644, NULL, &proc_dointvec},	{KERN_CORE_USES_PID, "core_uses_pid", &core_uses_pid, sizeof(int),	 0644, NULL, &proc_dointvec},	{KERN_TAINTED, "tainted", &tainted, sizeof(int),	 0644, NULL, &proc_dointvec},	{KERN_CAP_BSET, "cap-bound", &cap_bset, sizeof(kernel_cap_t),	 0600, NULL, &proc_dointvec_bset},#ifdef CONFIG_BLK_DEV_INITRD	{KERN_REALROOTDEV, "real-root-dev", &real_root_dev, sizeof(int),	 0644, NULL, &proc_dointvec},#endif#ifdef __sparc__	{KERN_SPARC_REBOOT, "reboot-cmd", reboot_command,	 256, 0644, NULL, &proc_dostring, &sysctl_string },	{KERN_SPARC_STOP_A, "stop-a", &stop_a_enabled, sizeof (int),	 0644, NULL, &proc_dointvec},#endif#if defined(CONFIG_PPC32) && defined(CONFIG_6xx)	{KERN_PPC_POWERSAVE_NAP, "powersave-nap", &powersave_nap, sizeof(int),	 0644, NULL, &proc_dointvec},	{KERN_PPC_L2CR, "l2cr", NULL, 0,	 0644, NULL, &proc_dol2crvec},#endif	{KERN_CTLALTDEL, "ctrl-alt-del", &C_A_D, sizeof(int),	 0644, NULL, &proc_dointvec},	{KERN_PRINTK, "printk", &console_loglevel, 4*sizeof(int),	 0644, NULL, &proc_dointvec},#ifdef CONFIG_KMOD	{KERN_MODPROBE, "modprobe", &modprobe_path, 256,	 0644, NULL, &proc_dostring, &sysctl_string },#endif#ifdef CONFIG_HOTPLUG	{KERN_HOTPLUG, "hotplug", &hotplug_path, 256,	 0644, NULL, &proc_dostring, &sysctl_string },#endif#ifdef CONFIG_CHR_DEV_SG	{KERN_SG_BIG_BUFF, "sg-big-buff", &sg_big_buff, sizeof (int),	 0444, NULL, &proc_dointvec},#endif#ifdef CONFIG_BSD_PROCESS_ACCT	{KERN_ACCT, "acct", &acct_parm, 3*sizeof(int),	0644, NULL, &proc_dointvec},#endif	{KERN_RTSIGNR, "rtsig-nr", &nr_queued_signals, sizeof(int),	 0444, NULL, &proc_dointvec},	{KERN_RTSIGMAX, "rtsig-max", &max_queued_signals, sizeof(int),	 0644, NULL, &proc_dointvec},#ifdef CONFIG_SYSVIPC	{KERN_SHMMAX, "shmmax", &shm_ctlmax, sizeof (size_t),	 0644, NULL, &proc_doulongvec_minmax},	{KERN_SHMALL, "shmall", &shm_ctlall, sizeof (size_t),	 0644, NULL, &proc_doulongvec_minmax},	{KERN_SHMMNI, "shmmni", &shm_ctlmni, sizeof (int),	 0644, NULL, &proc_dointvec},	{KERN_MSGMAX, "msgmax", &msg_ctlmax, sizeof (int),	 0644, NULL, &proc_dointvec},	{KERN_MSGMNI, "msgmni", &msg_ctlmni, sizeof (int),	 0644, NULL, &proc_dointvec},	{KERN_MSGMNB, "msgmnb", &msg_ctlmnb, sizeof (int),	 0644, NULL, &proc_dointvec},	{KERN_SEM, "sem", &sem_ctls, 4*sizeof (int),	 0644, NULL, &proc_dointvec},#endif#ifdef CONFIG_MAGIC_SYSRQ	{KERN_SYSRQ, "sysrq", &sysrq_enabled, sizeof (int),	 0644, NULL, &proc_dointvec},#endif	 	{KERN_CADPID, "cad_pid", &cad_pid, sizeof (int),	 0600, NULL, &proc_dointvec},	{KERN_MAX_THREADS, "threads-max", &max_threads, sizeof(int),	 0644, NULL, &proc_dointvec},	{KERN_RANDOM, "random", NULL, 0, 0555, random_table},	{KERN_OVERFLOWUID, "overflowuid", &overflowuid, sizeof(int), 0644, NULL,	 &proc_dointvec_minmax, &sysctl_intvec, NULL,	 &minolduid, &maxolduid},	{KERN_OVERFLOWGID, "overflowgid", &overflowgid, sizeof(int), 0644, NULL,	 &proc_dointvec_minmax, &sysctl_intvec, NULL,	 &minolduid, &maxolduid},#ifdef CONFIG_ARCH_S390#ifdef CONFIG_MATHEMU	{KERN_IEEE_EMULATION_WARNINGS,"ieee_emulation_warnings",	 &sysctl_ieee_emulation_warnings,sizeof(int),0644,NULL,&proc_dointvec},#endif	{KERN_S390_USER_DEBUG_LOGGING,"userprocess_debug",	 &sysctl_userprocess_debug,sizeof(int),0644,NULL,&proc_dointvec},#endif	{0}};static ctl_table vm_table[] = {	{VM_BDFLUSH, "bdflush", &bdf_prm, 9*sizeof(int), 0644, NULL,	 &proc_dointvec_minmax, &sysctl_intvec, NULL,	 &bdflush_min, &bdflush_max},	{VM_OVERCOMMIT_MEMORY, "overcommit_memory", &sysctl_overcommit_memory,	 sizeof(sysctl_overcommit_memory), 0644, NULL, &proc_dointvec},	{VM_OVERCOMMIT_RATIO, "overcommit_ratio",	 &sysctl_overcommit_ratio, sizeof(sysctl_overcommit_ratio), 0644,	 NULL, &proc_dointvec},	{VM_PAGERDAEMON, "kswapd",	 &pager_daemon, sizeof(pager_daemon_t), 0644, NULL, &proc_dointvec},	{VM_PGT_CACHE, "pagetable_cache", 	 &pgt_cache_water, 2*sizeof(int), 0644, NULL, &proc_dointvec},	{VM_PAGE_CLUSTER, "page-cluster", 	 &page_cluster, sizeof(int), 0644, NULL, &proc_dointvec},	{VM_MIN_READAHEAD, "min-readahead",	&vm_min_readahead,sizeof(int), 0644, NULL, &proc_dointvec},	{VM_MAX_READAHEAD, "max-readahead",	&vm_max_readahead,sizeof(int), 0644, NULL, &proc_dointvec},	{VM_MAX_MAP_COUNT, "max_map_count",	 &max_map_count, sizeof(int), 0644, NULL, &proc_dointvec},	{0}};static ctl_table proc_table[] = {	{0}};static ctl_table fs_table[] = {	{FS_NRINODE, "inode-nr", &inodes_stat, 2*sizeof(int),	 0444, NULL, &proc_dointvec},	{FS_STATINODE, "inode-state", &inodes_stat, 7*sizeof(int),	 0444, NULL, &proc_dointvec},	{FS_NRFILE, "file-nr", &files_stat, 3*sizeof(int),	 0444, NULL, &proc_dointvec},	{FS_MAXFILE, "file-max", &files_stat.max_files, sizeof(int),	 0644, NULL, &proc_dointvec},	{FS_NRDQUOT, "dquot-nr", &nr_dquots, 2*sizeof(int),	 0444, NULL, &proc_dointvec},	{FS_DENTRY, "dentry-state", &dentry_stat, 6*sizeof(int),	 0444, NULL, &proc_dointvec},	{FS_OVERFLOWUID, "overflowuid", &fs_overflowuid, sizeof(int), 0644, NULL,	 &proc_dointvec_minmax, &sysctl_intvec, NULL,	 &minolduid, &maxolduid},	{FS_OVERFLOWGID, "overflowgid", &fs_overflowgid, sizeof(int), 0644, NULL,	 &proc_dointvec_minmax, &sysctl_intvec, NULL,	 &minolduid, &maxolduid},	{FS_LEASES, "leases-enable", &leases_enable, sizeof(int),	 0644, NULL, &proc_dointvec},	{FS_DIR_NOTIFY, "dir-notify-enable", &dir_notify_enable,	 sizeof(int), 0644, NULL, &proc_dointvec},	{FS_LEASE_TIME, "lease-break-time", &lease_break_time, sizeof(int),	 0644, NULL, &proc_dointvec},	{0}};static ctl_table debug_table[] = {	{0}};static ctl_table dev_table[] = {	{0}};  extern void init_irq_proc (void);void __init sysctl_init(void){#ifdef CONFIG_PROC_FS	register_proc_table(root_table, proc_sys_root);	init_irq_proc();#endif}int do_sysctl(int *name, int nlen, void *oldval, size_t *oldlenp,	       void *newval, size_t newlen){	struct list_head *tmp;	if (nlen <= 0 || nlen >= CTL_MAXNAME)		return -ENOTDIR;	if (oldval) {		int old_len;		if (!oldlenp || get_user(old_len, oldlenp))			return -EFAULT;	}	tmp = &root_table_header.ctl_entry;	do {		struct ctl_table_header *head =			list_entry(tmp, struct ctl_table_header, ctl_entry);		void *context = NULL;		int error = parse_table(name, nlen, oldval, oldlenp, 					newval, newlen, head->ctl_table,					&context);		if (context)			kfree(context);		if (error != -ENOTDIR)			return error;		tmp = tmp->next;	} while (tmp != &root_table_header.ctl_entry);	return -ENOTDIR;}extern asmlinkage long sys_sysctl(struct __sysctl_args *args){	struct __sysctl_args tmp;	int error;	if (copy_from_user(&tmp, args, sizeof(tmp)))		return -EFAULT;			lock_kernel();	error = do_sysctl(tmp.name, tmp.nlen, tmp.oldval, tmp.oldlenp,			  tmp.newval, tmp.newlen);	unlock_kernel();	return error;}/* * ctl_perm does NOT grant the superuser all rights automatically, because * some sysctl variables are readonly even to root. */static int test_perm(int mode, int op){	if (!current->euid)		mode >>= 6;	else if (in_egroup_p(0))		mode >>= 3;	if ((mode & op & 0007) == op)		return 0;	return -EACCES;}static inline int ctl_perm(ctl_table *table, int op){	return test_perm(table->mode, op);}static int parse_table(int *name, int nlen,		       void *oldval, size_t *oldlenp,		       void *newval, size_t newlen,		       ctl_table *table, void **context){	int n;repeat:	if (!nlen)		return -ENOTDIR;	if (get_user(n, name))		return -EFAULT;	for ( ; table->ctl_name; table++) {		if (n == table->ctl_name || table->ctl_name == CTL_ANY) {			int error;			if (table->child) {				if (ctl_perm(table, 001))					return -EPERM;				if (table->strategy) {					error = table->strategy(						table, name, nlen,						oldval, oldlenp,						newval, newlen, context);					if (error)						return error;				}				name++;				nlen--;				table = table->child;				goto repeat;			}			error = do_sysctl_strategy(table, name, nlen,						   oldval, oldlenp,						   newval, newlen, context);			return error;		}	}	return -ENOTDIR;}/* Perform the actual read/write of a sysctl table entry. */int do_sysctl_strategy (ctl_table *table, 			int *name, int nlen,			void *oldval, size_t *oldlenp,			void *newval, size_t newlen, void **context){	int op = 0, rc;	size_t len;	if (oldval)		op |= 004;	if (newval) 		op |= 002;	if (ctl_perm(table, op))		return -EPERM;	if (table->strategy) {		rc = table->strategy(table, name, nlen, oldval, oldlenp,				     newval, newlen, context);		if (rc < 0)			return rc;		if (rc > 0)			return 0;	}	/* If there is no strategy routine, or if the strategy returns	 * zero, proceed with automatic r/w */	if (table->data && table->maxlen) {		if (oldval && oldlenp) {			get_user(len, oldlenp);			if (len) {				if (len > table->maxlen)					len = table->maxlen;				if(copy_to_user(oldval, table->data, len))					return -EFAULT;				if(put_user(len, oldlenp))					return -EFAULT;			}		}		if (newval && newlen) {			len = newlen;			if (len > table->maxlen)				len = table->maxlen;			if(copy_from_user(table->data, newval, len))				return -EFAULT;		}	}	return 0;}/** * register_sysctl_table - register a sysctl hierarchy * @table: the top-level table structure * @insert_at_head: whether the entry should be inserted in front or at the end * * Register a sysctl table hierarchy. @table should be a filled in ctl_table * array. An entry with a ctl_name of 0 terminates the table.  * * The members of the &ctl_table structure are used as follows: *