4 * Copyright (C) 1991, 1992 Linus Torvalds
7 #include <linux/module.h>
9 #include <linux/utsname.h>
10 #include <linux/mman.h>
11 #include <linux/smp_lock.h>
12 #include <linux/notifier.h>
13 #include <linux/reboot.h>
14 #include <linux/prctl.h>
15 #include <linux/highuid.h>
17 #include <linux/resource.h>
18 #include <linux/kernel.h>
19 #include <linux/kexec.h>
20 #include <linux/workqueue.h>
21 #include <linux/capability.h>
22 #include <linux/device.h>
23 #include <linux/key.h>
24 #include <linux/times.h>
25 #include <linux/posix-timers.h>
26 #include <linux/security.h>
27 #include <linux/dcookies.h>
28 #include <linux/suspend.h>
29 #include <linux/tty.h>
30 #include <linux/signal.h>
31 #include <linux/cn_proc.h>
32 #include <linux/getcpu.h>
33 #include <linux/task_io_accounting_ops.h>
34 #include <linux/seccomp.h>
35 #include <linux/cpu.h>
37 #include <linux/compat.h>
38 #include <linux/syscalls.h>
39 #include <linux/kprobes.h>
40 #include <linux/user_namespace.h>
42 #include <asm/uaccess.h>
44 #include <asm/unistd.h>
46 #ifndef SET_UNALIGN_CTL
47 # define SET_UNALIGN_CTL(a,b) (-EINVAL)
49 #ifndef GET_UNALIGN_CTL
50 # define GET_UNALIGN_CTL(a,b) (-EINVAL)
53 # define SET_FPEMU_CTL(a,b) (-EINVAL)
56 # define GET_FPEMU_CTL(a,b) (-EINVAL)
59 # define SET_FPEXC_CTL(a,b) (-EINVAL)
62 # define GET_FPEXC_CTL(a,b) (-EINVAL)
65 # define GET_ENDIAN(a,b) (-EINVAL)
68 # define SET_ENDIAN(a,b) (-EINVAL)
71 # define GET_TSC_CTL(a) (-EINVAL)
74 # define SET_TSC_CTL(a) (-EINVAL)
78 * this is where the system-wide overflow UID and GID are defined, for
79 * architectures that now have 32-bit UID/GID but didn't in the past
82 int overflowuid = DEFAULT_OVERFLOWUID;
83 int overflowgid = DEFAULT_OVERFLOWGID;
86 EXPORT_SYMBOL(overflowuid);
87 EXPORT_SYMBOL(overflowgid);
91 * the same as above, but for filesystems which can only store a 16-bit
92 * UID and GID. as such, this is needed on all architectures
95 int fs_overflowuid = DEFAULT_FS_OVERFLOWUID;
96 int fs_overflowgid = DEFAULT_FS_OVERFLOWUID;
98 EXPORT_SYMBOL(fs_overflowuid);
99 EXPORT_SYMBOL(fs_overflowgid);
102 * this indicates whether you can reboot with ctrl-alt-del: the default is yes
107 EXPORT_SYMBOL(cad_pid);
110 * If set, this is used for preparing the system to power off.
113 void (*pm_power_off_prepare)(void);
115 static int set_one_prio(struct task_struct *p, int niceval, int error)
119 if (p->uid != current->euid &&
120 p->euid != current->euid && !capable(CAP_SYS_NICE)) {
124 if (niceval < task_nice(p) && !can_nice(p, niceval)) {
128 no_nice = security_task_setnice(p, niceval);
135 set_user_nice(p, niceval);
140 SYSCALL_DEFINE3(setpriority, int, which, int, who, int, niceval)
142 struct task_struct *g, *p;
143 struct user_struct *user;
147 if (which > PRIO_USER || which < PRIO_PROCESS)
150 /* normalize: avoid signed division (rounding problems) */
157 read_lock(&tasklist_lock);
161 p = find_task_by_vpid(who);
165 error = set_one_prio(p, niceval, error);
169 pgrp = find_vpid(who);
171 pgrp = task_pgrp(current);
172 do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {
173 error = set_one_prio(p, niceval, error);
174 } while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
177 user = current->user;
181 if ((who != current->uid) && !(user = find_user(who)))
182 goto out_unlock; /* No processes for this user */
186 error = set_one_prio(p, niceval, error);
187 while_each_thread(g, p);
188 if (who != current->uid)
189 free_uid(user); /* For find_user() */
193 read_unlock(&tasklist_lock);
199 * Ugh. To avoid negative return values, "getpriority()" will
200 * not return the normal nice-value, but a negated value that
201 * has been offset by 20 (ie it returns 40..1 instead of -20..19)
202 * to stay compatible.
204 SYSCALL_DEFINE2(getpriority, int, which, int, who)
206 struct task_struct *g, *p;
207 struct user_struct *user;
208 long niceval, retval = -ESRCH;
211 if (which > PRIO_USER || which < PRIO_PROCESS)
214 read_lock(&tasklist_lock);
218 p = find_task_by_vpid(who);
222 niceval = 20 - task_nice(p);
223 if (niceval > retval)
229 pgrp = find_vpid(who);
231 pgrp = task_pgrp(current);
232 do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {
233 niceval = 20 - task_nice(p);
234 if (niceval > retval)
236 } while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
239 user = current->user;
243 if ((who != current->uid) && !(user = find_user(who)))
244 goto out_unlock; /* No processes for this user */
248 niceval = 20 - task_nice(p);
249 if (niceval > retval)
252 while_each_thread(g, p);
253 if (who != current->uid)
254 free_uid(user); /* for find_user() */
258 read_unlock(&tasklist_lock);
264 * emergency_restart - reboot the system
266 * Without shutting down any hardware or taking any locks
267 * reboot the system. This is called when we know we are in
268 * trouble so this is our best effort to reboot. This is
269 * safe to call in interrupt context.
271 void emergency_restart(void)
273 machine_emergency_restart();
275 EXPORT_SYMBOL_GPL(emergency_restart);
277 void kernel_restart_prepare(char *cmd)
279 blocking_notifier_call_chain(&reboot_notifier_list, SYS_RESTART, cmd);
280 system_state = SYSTEM_RESTART;
286 * kernel_restart - reboot the system
287 * @cmd: pointer to buffer containing command to execute for restart
290 * Shutdown everything and perform a clean reboot.
291 * This is not safe to call in interrupt context.
293 void kernel_restart(char *cmd)
295 kernel_restart_prepare(cmd);
297 printk(KERN_EMERG "Restarting system.\n");
299 printk(KERN_EMERG "Restarting system with command '%s'.\n", cmd);
300 machine_restart(cmd);
302 EXPORT_SYMBOL_GPL(kernel_restart);
304 static void kernel_shutdown_prepare(enum system_states state)
306 blocking_notifier_call_chain(&reboot_notifier_list,
307 (state == SYSTEM_HALT)?SYS_HALT:SYS_POWER_OFF, NULL);
308 system_state = state;
312 * kernel_halt - halt the system
314 * Shutdown everything and perform a clean system halt.
316 void kernel_halt(void)
318 kernel_shutdown_prepare(SYSTEM_HALT);
320 printk(KERN_EMERG "System halted.\n");
324 EXPORT_SYMBOL_GPL(kernel_halt);
327 * kernel_power_off - power_off the system
329 * Shutdown everything and perform a clean system power_off.
331 void kernel_power_off(void)
333 kernel_shutdown_prepare(SYSTEM_POWER_OFF);
334 if (pm_power_off_prepare)
335 pm_power_off_prepare();
336 disable_nonboot_cpus();
338 printk(KERN_EMERG "Power down.\n");
341 EXPORT_SYMBOL_GPL(kernel_power_off);
343 * Reboot system call: for obvious reasons only root may call it,
344 * and even root needs to set up some magic numbers in the registers
345 * so that some mistake won't make this reboot the whole machine.
346 * You can also set the meaning of the ctrl-alt-del-key here.
348 * reboot doesn't sync: do that yourself before calling this.
350 SYSCALL_DEFINE4(reboot, int, magic1, int, magic2, unsigned int, cmd,
355 /* We only trust the superuser with rebooting the system. */
356 if (!capable(CAP_SYS_BOOT))
359 /* For safety, we require "magic" arguments. */
360 if (magic1 != LINUX_REBOOT_MAGIC1 ||
361 (magic2 != LINUX_REBOOT_MAGIC2 &&
362 magic2 != LINUX_REBOOT_MAGIC2A &&
363 magic2 != LINUX_REBOOT_MAGIC2B &&
364 magic2 != LINUX_REBOOT_MAGIC2C))
367 /* Instead of trying to make the power_off code look like
368 * halt when pm_power_off is not set do it the easy way.
370 if ((cmd == LINUX_REBOOT_CMD_POWER_OFF) && !pm_power_off)
371 cmd = LINUX_REBOOT_CMD_HALT;
375 case LINUX_REBOOT_CMD_RESTART:
376 kernel_restart(NULL);
379 case LINUX_REBOOT_CMD_CAD_ON:
383 case LINUX_REBOOT_CMD_CAD_OFF:
387 case LINUX_REBOOT_CMD_HALT:
393 case LINUX_REBOOT_CMD_POWER_OFF:
399 case LINUX_REBOOT_CMD_RESTART2:
400 if (strncpy_from_user(&buffer[0], arg, sizeof(buffer) - 1) < 0) {
404 buffer[sizeof(buffer) - 1] = '\0';
406 kernel_restart(buffer);
410 case LINUX_REBOOT_CMD_KEXEC:
413 ret = kernel_kexec();
419 #ifdef CONFIG_HIBERNATION
420 case LINUX_REBOOT_CMD_SW_SUSPEND:
422 int ret = hibernate();
436 static void deferred_cad(struct work_struct *dummy)
438 kernel_restart(NULL);
442 * This function gets called by ctrl-alt-del - ie the keyboard interrupt.
443 * As it's called within an interrupt, it may NOT sync: the only choice
444 * is whether to reboot at once, or just ignore the ctrl-alt-del.
446 void ctrl_alt_del(void)
448 static DECLARE_WORK(cad_work, deferred_cad);
451 schedule_work(&cad_work);
453 kill_cad_pid(SIGINT, 1);
457 * Unprivileged users may change the real gid to the effective gid
458 * or vice versa. (BSD-style)
460 * If you set the real gid at all, or set the effective gid to a value not
461 * equal to the real gid, then the saved gid is set to the new effective gid.
463 * This makes it possible for a setgid program to completely drop its
464 * privileges, which is often a useful assertion to make when you are doing
465 * a security audit over a program.
467 * The general idea is that a program which uses just setregid() will be
468 * 100% compatible with BSD. A program which uses just setgid() will be
469 * 100% compatible with POSIX with saved IDs.
471 * SMP: There are not races, the GIDs are checked only by filesystem
472 * operations (as far as semantic preservation is concerned).
474 SYSCALL_DEFINE2(setregid, gid_t, rgid, gid_t, egid)
476 int old_rgid = current->gid;
477 int old_egid = current->egid;
478 int new_rgid = old_rgid;
479 int new_egid = old_egid;
482 retval = security_task_setgid(rgid, egid, (gid_t)-1, LSM_SETID_RE);
486 if (rgid != (gid_t) -1) {
487 if ((old_rgid == rgid) ||
488 (current->egid==rgid) ||
494 if (egid != (gid_t) -1) {
495 if ((old_rgid == egid) ||
496 (current->egid == egid) ||
497 (current->sgid == egid) ||
503 if (new_egid != old_egid) {
504 set_dumpable(current->mm, suid_dumpable);
507 if (rgid != (gid_t) -1 ||
508 (egid != (gid_t) -1 && egid != old_rgid))
509 current->sgid = new_egid;
510 current->fsgid = new_egid;
511 current->egid = new_egid;
512 current->gid = new_rgid;
513 key_fsgid_changed(current);
514 proc_id_connector(current, PROC_EVENT_GID);
519 * setgid() is implemented like SysV w/ SAVED_IDS
521 * SMP: Same implicit races as above.
523 SYSCALL_DEFINE1(setgid, gid_t, gid)
525 int old_egid = current->egid;
528 retval = security_task_setgid(gid, (gid_t)-1, (gid_t)-1, LSM_SETID_ID);
532 if (capable(CAP_SETGID)) {
533 if (old_egid != gid) {
534 set_dumpable(current->mm, suid_dumpable);
537 current->gid = current->egid = current->sgid = current->fsgid = gid;
538 } else if ((gid == current->gid) || (gid == current->sgid)) {
539 if (old_egid != gid) {
540 set_dumpable(current->mm, suid_dumpable);
543 current->egid = current->fsgid = gid;
548 key_fsgid_changed(current);
549 proc_id_connector(current, PROC_EVENT_GID);
553 static int set_user(uid_t new_ruid, int dumpclear)
555 struct user_struct *new_user;
557 new_user = alloc_uid(current->nsproxy->user_ns, new_ruid);
561 if (atomic_read(&new_user->processes) >=
562 current->signal->rlim[RLIMIT_NPROC].rlim_cur &&
563 new_user != current->nsproxy->user_ns->root_user) {
568 switch_uid(new_user);
571 set_dumpable(current->mm, suid_dumpable);
574 current->uid = new_ruid;
579 * Unprivileged users may change the real uid to the effective uid
580 * or vice versa. (BSD-style)
582 * If you set the real uid at all, or set the effective uid to a value not
583 * equal to the real uid, then the saved uid is set to the new effective uid.
585 * This makes it possible for a setuid program to completely drop its
586 * privileges, which is often a useful assertion to make when you are doing
587 * a security audit over a program.
589 * The general idea is that a program which uses just setreuid() will be
590 * 100% compatible with BSD. A program which uses just setuid() will be
591 * 100% compatible with POSIX with saved IDs.
593 SYSCALL_DEFINE2(setreuid, uid_t, ruid, uid_t, euid)
595 int old_ruid, old_euid, old_suid, new_ruid, new_euid;
598 retval = security_task_setuid(ruid, euid, (uid_t)-1, LSM_SETID_RE);
602 new_ruid = old_ruid = current->uid;
603 new_euid = old_euid = current->euid;
604 old_suid = current->suid;
606 if (ruid != (uid_t) -1) {
608 if ((old_ruid != ruid) &&
609 (current->euid != ruid) &&
610 !capable(CAP_SETUID))
614 if (euid != (uid_t) -1) {
616 if ((old_ruid != euid) &&
617 (current->euid != euid) &&
618 (current->suid != euid) &&
619 !capable(CAP_SETUID))
623 if (new_ruid != old_ruid && set_user(new_ruid, new_euid != old_euid) < 0)
626 if (new_euid != old_euid) {
627 set_dumpable(current->mm, suid_dumpable);
630 current->fsuid = current->euid = new_euid;
631 if (ruid != (uid_t) -1 ||
632 (euid != (uid_t) -1 && euid != old_ruid))
633 current->suid = current->euid;
634 current->fsuid = current->euid;
636 key_fsuid_changed(current);
637 proc_id_connector(current, PROC_EVENT_UID);
639 return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_RE);
645 * setuid() is implemented like SysV with SAVED_IDS
647 * Note that SAVED_ID's is deficient in that a setuid root program
648 * like sendmail, for example, cannot set its uid to be a normal
649 * user and then switch back, because if you're root, setuid() sets
650 * the saved uid too. If you don't like this, blame the bright people
651 * in the POSIX committee and/or USG. Note that the BSD-style setreuid()
652 * will allow a root program to temporarily drop privileges and be able to
653 * regain them by swapping the real and effective uid.
655 SYSCALL_DEFINE1(setuid, uid_t, uid)
657 int old_euid = current->euid;
658 int old_ruid, old_suid, new_suid;
661 retval = security_task_setuid(uid, (uid_t)-1, (uid_t)-1, LSM_SETID_ID);
665 old_ruid = current->uid;
666 old_suid = current->suid;
669 if (capable(CAP_SETUID)) {
670 if (uid != old_ruid && set_user(uid, old_euid != uid) < 0)
673 } else if ((uid != current->uid) && (uid != new_suid))
676 if (old_euid != uid) {
677 set_dumpable(current->mm, suid_dumpable);
680 current->fsuid = current->euid = uid;
681 current->suid = new_suid;
683 key_fsuid_changed(current);
684 proc_id_connector(current, PROC_EVENT_UID);
686 return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_ID);
691 * This function implements a generic ability to update ruid, euid,
692 * and suid. This allows you to implement the 4.4 compatible seteuid().
694 SYSCALL_DEFINE3(setresuid, uid_t, ruid, uid_t, euid, uid_t, suid)
696 int old_ruid = current->uid;
697 int old_euid = current->euid;
698 int old_suid = current->suid;
701 retval = security_task_setuid(ruid, euid, suid, LSM_SETID_RES);
705 if (!capable(CAP_SETUID)) {
706 if ((ruid != (uid_t) -1) && (ruid != current->uid) &&
707 (ruid != current->euid) && (ruid != current->suid))
709 if ((euid != (uid_t) -1) && (euid != current->uid) &&
710 (euid != current->euid) && (euid != current->suid))
712 if ((suid != (uid_t) -1) && (suid != current->uid) &&
713 (suid != current->euid) && (suid != current->suid))
716 if (ruid != (uid_t) -1) {
717 if (ruid != current->uid && set_user(ruid, euid != current->euid) < 0)
720 if (euid != (uid_t) -1) {
721 if (euid != current->euid) {
722 set_dumpable(current->mm, suid_dumpable);
725 current->euid = euid;
727 current->fsuid = current->euid;
728 if (suid != (uid_t) -1)
729 current->suid = suid;
731 key_fsuid_changed(current);
732 proc_id_connector(current, PROC_EVENT_UID);
734 return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_RES);
737 SYSCALL_DEFINE3(getresuid, uid_t __user *, ruid, uid_t __user *, euid, uid_t __user *, suid)
741 if (!(retval = put_user(current->uid, ruid)) &&
742 !(retval = put_user(current->euid, euid)))
743 retval = put_user(current->suid, suid);
749 * Same as above, but for rgid, egid, sgid.
751 SYSCALL_DEFINE3(setresgid, gid_t, rgid, gid_t, egid, gid_t, sgid)
755 retval = security_task_setgid(rgid, egid, sgid, LSM_SETID_RES);
759 if (!capable(CAP_SETGID)) {
760 if ((rgid != (gid_t) -1) && (rgid != current->gid) &&
761 (rgid != current->egid) && (rgid != current->sgid))
763 if ((egid != (gid_t) -1) && (egid != current->gid) &&
764 (egid != current->egid) && (egid != current->sgid))
766 if ((sgid != (gid_t) -1) && (sgid != current->gid) &&
767 (sgid != current->egid) && (sgid != current->sgid))
770 if (egid != (gid_t) -1) {
771 if (egid != current->egid) {
772 set_dumpable(current->mm, suid_dumpable);
775 current->egid = egid;
777 current->fsgid = current->egid;
778 if (rgid != (gid_t) -1)
780 if (sgid != (gid_t) -1)
781 current->sgid = sgid;
783 key_fsgid_changed(current);
784 proc_id_connector(current, PROC_EVENT_GID);
788 SYSCALL_DEFINE3(getresgid, gid_t __user *, rgid, gid_t __user *, egid, gid_t __user *, sgid)
792 if (!(retval = put_user(current->gid, rgid)) &&
793 !(retval = put_user(current->egid, egid)))
794 retval = put_user(current->sgid, sgid);
801 * "setfsuid()" sets the fsuid - the uid used for filesystem checks. This
802 * is used for "access()" and for the NFS daemon (letting nfsd stay at
803 * whatever uid it wants to). It normally shadows "euid", except when
804 * explicitly set by setfsuid() or for access..
806 SYSCALL_DEFINE1(setfsuid, uid_t, uid)
810 old_fsuid = current->fsuid;
811 if (security_task_setuid(uid, (uid_t)-1, (uid_t)-1, LSM_SETID_FS))
814 if (uid == current->uid || uid == current->euid ||
815 uid == current->suid || uid == current->fsuid ||
816 capable(CAP_SETUID)) {
817 if (uid != old_fsuid) {
818 set_dumpable(current->mm, suid_dumpable);
821 current->fsuid = uid;
824 key_fsuid_changed(current);
825 proc_id_connector(current, PROC_EVENT_UID);
827 security_task_post_setuid(old_fsuid, (uid_t)-1, (uid_t)-1, LSM_SETID_FS);
833 * Samma på svenska..
835 SYSCALL_DEFINE1(setfsgid, gid_t, gid)
839 old_fsgid = current->fsgid;
840 if (security_task_setgid(gid, (gid_t)-1, (gid_t)-1, LSM_SETID_FS))
843 if (gid == current->gid || gid == current->egid ||
844 gid == current->sgid || gid == current->fsgid ||
845 capable(CAP_SETGID)) {
846 if (gid != old_fsgid) {
847 set_dumpable(current->mm, suid_dumpable);
850 current->fsgid = gid;
851 key_fsgid_changed(current);
852 proc_id_connector(current, PROC_EVENT_GID);
857 void do_sys_times(struct tms *tms)
859 struct task_cputime cputime;
860 cputime_t cutime, cstime;
862 spin_lock_irq(¤t->sighand->siglock);
863 thread_group_cputime(current, &cputime);
864 cutime = current->signal->cutime;
865 cstime = current->signal->cstime;
866 spin_unlock_irq(¤t->sighand->siglock);
867 tms->tms_utime = cputime_to_clock_t(cputime.utime);
868 tms->tms_stime = cputime_to_clock_t(cputime.stime);
869 tms->tms_cutime = cputime_to_clock_t(cutime);
870 tms->tms_cstime = cputime_to_clock_t(cstime);
873 SYSCALL_DEFINE1(times, struct tms __user *, tbuf)
879 if (copy_to_user(tbuf, &tmp, sizeof(struct tms)))
882 return (long) jiffies_64_to_clock_t(get_jiffies_64());
886 * This needs some heavy checking ...
887 * I just haven't the stomach for it. I also don't fully
888 * understand sessions/pgrp etc. Let somebody who does explain it.
890 * OK, I think I have the protection semantics right.... this is really
891 * only important on a multi-user system anyway, to make sure one user
892 * can't send a signal to a process owned by another. -TYT, 12/12/91
894 * Auch. Had to add the 'did_exec' flag to conform completely to POSIX.
897 SYSCALL_DEFINE2(setpgid, pid_t, pid, pid_t, pgid)
899 struct task_struct *p;
900 struct task_struct *group_leader = current->group_leader;
905 pid = task_pid_vnr(group_leader);
911 /* From this point forward we keep holding onto the tasklist lock
912 * so that our parent does not change from under us. -DaveM
914 write_lock_irq(&tasklist_lock);
917 p = find_task_by_vpid(pid);
922 if (!thread_group_leader(p))
925 if (same_thread_group(p->real_parent, group_leader)) {
927 if (task_session(p) != task_session(group_leader))
934 if (p != group_leader)
939 if (p->signal->leader)
944 struct task_struct *g;
946 pgrp = find_vpid(pgid);
947 g = pid_task(pgrp, PIDTYPE_PGID);
948 if (!g || task_session(g) != task_session(group_leader))
952 err = security_task_setpgid(p, pgid);
956 if (task_pgrp(p) != pgrp) {
957 change_pid(p, PIDTYPE_PGID, pgrp);
958 set_task_pgrp(p, pid_nr(pgrp));
963 /* All paths lead to here, thus we are safe. -DaveM */
964 write_unlock_irq(&tasklist_lock);
968 SYSCALL_DEFINE1(getpgid, pid_t, pid)
970 struct task_struct *p;
976 grp = task_pgrp(current);
979 p = find_task_by_vpid(pid);
986 retval = security_task_getpgid(p);
990 retval = pid_vnr(grp);
996 #ifdef __ARCH_WANT_SYS_GETPGRP
998 SYSCALL_DEFINE0(getpgrp)
1000 return sys_getpgid(0);
1005 SYSCALL_DEFINE1(getsid, pid_t, pid)
1007 struct task_struct *p;
1013 sid = task_session(current);
1016 p = find_task_by_vpid(pid);
1019 sid = task_session(p);
1023 retval = security_task_getsid(p);
1027 retval = pid_vnr(sid);
1033 SYSCALL_DEFINE0(setsid)
1035 struct task_struct *group_leader = current->group_leader;
1036 struct pid *sid = task_pid(group_leader);
1037 pid_t session = pid_vnr(sid);
1040 write_lock_irq(&tasklist_lock);
1041 /* Fail if I am already a session leader */
1042 if (group_leader->signal->leader)
1045 /* Fail if a process group id already exists that equals the
1046 * proposed session id.
1048 if (pid_task(sid, PIDTYPE_PGID))
1051 group_leader->signal->leader = 1;
1052 __set_special_pids(sid);
1054 proc_clear_tty(group_leader);
1058 write_unlock_irq(&tasklist_lock);
1063 * Supplementary group IDs
1066 /* init to 2 - one for init_task, one to ensure it is never freed */
1067 struct group_info init_groups = { .usage = ATOMIC_INIT(2) };
1069 struct group_info *groups_alloc(int gidsetsize)
1071 struct group_info *group_info;
1075 nblocks = (gidsetsize + NGROUPS_PER_BLOCK - 1) / NGROUPS_PER_BLOCK;
1076 /* Make sure we always allocate at least one indirect block pointer */
1077 nblocks = nblocks ? : 1;
1078 group_info = kmalloc(sizeof(*group_info) + nblocks*sizeof(gid_t *), GFP_USER);
1081 group_info->ngroups = gidsetsize;
1082 group_info->nblocks = nblocks;
1083 atomic_set(&group_info->usage, 1);
1085 if (gidsetsize <= NGROUPS_SMALL)
1086 group_info->blocks[0] = group_info->small_block;
1088 for (i = 0; i < nblocks; i++) {
1090 b = (void *)__get_free_page(GFP_USER);
1092 goto out_undo_partial_alloc;
1093 group_info->blocks[i] = b;
1098 out_undo_partial_alloc:
1100 free_page((unsigned long)group_info->blocks[i]);
1106 EXPORT_SYMBOL(groups_alloc);
1108 void groups_free(struct group_info *group_info)
1110 if (group_info->blocks[0] != group_info->small_block) {
1112 for (i = 0; i < group_info->nblocks; i++)
1113 free_page((unsigned long)group_info->blocks[i]);
1118 EXPORT_SYMBOL(groups_free);
1120 /* export the group_info to a user-space array */
1121 static int groups_to_user(gid_t __user *grouplist,
1122 struct group_info *group_info)
1125 unsigned int count = group_info->ngroups;
1127 for (i = 0; i < group_info->nblocks; i++) {
1128 unsigned int cp_count = min(NGROUPS_PER_BLOCK, count);
1129 unsigned int len = cp_count * sizeof(*grouplist);
1131 if (copy_to_user(grouplist, group_info->blocks[i], len))
1134 grouplist += NGROUPS_PER_BLOCK;
1140 /* fill a group_info from a user-space array - it must be allocated already */
1141 static int groups_from_user(struct group_info *group_info,
1142 gid_t __user *grouplist)
1145 unsigned int count = group_info->ngroups;
1147 for (i = 0; i < group_info->nblocks; i++) {
1148 unsigned int cp_count = min(NGROUPS_PER_BLOCK, count);
1149 unsigned int len = cp_count * sizeof(*grouplist);
1151 if (copy_from_user(group_info->blocks[i], grouplist, len))
1154 grouplist += NGROUPS_PER_BLOCK;
1160 /* a simple Shell sort */
1161 static void groups_sort(struct group_info *group_info)
1163 int base, max, stride;
1164 int gidsetsize = group_info->ngroups;
1166 for (stride = 1; stride < gidsetsize; stride = 3 * stride + 1)
1171 max = gidsetsize - stride;
1172 for (base = 0; base < max; base++) {
1174 int right = left + stride;
1175 gid_t tmp = GROUP_AT(group_info, right);
1177 while (left >= 0 && GROUP_AT(group_info, left) > tmp) {
1178 GROUP_AT(group_info, right) =
1179 GROUP_AT(group_info, left);
1183 GROUP_AT(group_info, right) = tmp;
1189 /* a simple bsearch */
1190 int groups_search(struct group_info *group_info, gid_t grp)
1192 unsigned int left, right;
1198 right = group_info->ngroups;
1199 while (left < right) {
1200 unsigned int mid = (left+right)/2;
1201 int cmp = grp - GROUP_AT(group_info, mid);
1212 /* validate and set current->group_info */
1213 int set_current_groups(struct group_info *group_info)
1216 struct group_info *old_info;
1218 retval = security_task_setgroups(group_info);
1222 groups_sort(group_info);
1223 get_group_info(group_info);
1226 old_info = current->group_info;
1227 current->group_info = group_info;
1228 task_unlock(current);
1230 put_group_info(old_info);
1235 EXPORT_SYMBOL(set_current_groups);
1237 SYSCALL_DEFINE2(getgroups, int, gidsetsize, gid_t __user *, grouplist)
1242 * SMP: Nobody else can change our grouplist. Thus we are
1249 /* no need to grab task_lock here; it cannot change */
1250 i = current->group_info->ngroups;
1252 if (i > gidsetsize) {
1256 if (groups_to_user(grouplist, current->group_info)) {
1266 * SMP: Our groups are copy-on-write. We can set them safely
1267 * without another task interfering.
1270 SYSCALL_DEFINE2(setgroups, int, gidsetsize, gid_t __user *, grouplist)
1272 struct group_info *group_info;
1275 if (!capable(CAP_SETGID))
1277 if ((unsigned)gidsetsize > NGROUPS_MAX)
1280 group_info = groups_alloc(gidsetsize);
1283 retval = groups_from_user(group_info, grouplist);
1285 put_group_info(group_info);
1289 retval = set_current_groups(group_info);
1290 put_group_info(group_info);
1296 * Check whether we're fsgid/egid or in the supplemental group..
1298 int in_group_p(gid_t grp)
1301 if (grp != current->fsgid)
1302 retval = groups_search(current->group_info, grp);
1306 EXPORT_SYMBOL(in_group_p);
1308 int in_egroup_p(gid_t grp)
1311 if (grp != current->egid)
1312 retval = groups_search(current->group_info, grp);
1316 EXPORT_SYMBOL(in_egroup_p);
1318 DECLARE_RWSEM(uts_sem);
1320 SYSCALL_DEFINE1(newuname, struct new_utsname __user *, name)
1324 down_read(&uts_sem);
1325 if (copy_to_user(name, utsname(), sizeof *name))
1331 SYSCALL_DEFINE2(sethostname, char __user *, name, int, len)
1334 char tmp[__NEW_UTS_LEN];
1336 if (!capable(CAP_SYS_ADMIN))
1338 if (len < 0 || len > __NEW_UTS_LEN)
1340 down_write(&uts_sem);
1342 if (!copy_from_user(tmp, name, len)) {
1343 struct new_utsname *u = utsname();
1345 memcpy(u->nodename, tmp, len);
1346 memset(u->nodename + len, 0, sizeof(u->nodename) - len);
1353 #ifdef __ARCH_WANT_SYS_GETHOSTNAME
1355 SYSCALL_DEFINE2(gethostname, char __user *, name, int, len)
1358 struct new_utsname *u;
1362 down_read(&uts_sem);
1364 i = 1 + strlen(u->nodename);
1368 if (copy_to_user(name, u->nodename, i))
1377 * Only setdomainname; getdomainname can be implemented by calling
1380 SYSCALL_DEFINE2(setdomainname, char __user *, name, int, len)
1383 char tmp[__NEW_UTS_LEN];
1385 if (!capable(CAP_SYS_ADMIN))
1387 if (len < 0 || len > __NEW_UTS_LEN)
1390 down_write(&uts_sem);
1392 if (!copy_from_user(tmp, name, len)) {
1393 struct new_utsname *u = utsname();
1395 memcpy(u->domainname, tmp, len);
1396 memset(u->domainname + len, 0, sizeof(u->domainname) - len);
1403 SYSCALL_DEFINE2(getrlimit, unsigned int, resource, struct rlimit __user *, rlim)
1405 if (resource >= RLIM_NLIMITS)
1408 struct rlimit value;
1409 task_lock(current->group_leader);
1410 value = current->signal->rlim[resource];
1411 task_unlock(current->group_leader);
1412 return copy_to_user(rlim, &value, sizeof(*rlim)) ? -EFAULT : 0;
1416 #ifdef __ARCH_WANT_SYS_OLD_GETRLIMIT
1419 * Back compatibility for getrlimit. Needed for some apps.
1422 SYSCALL_DEFINE2(old_getrlimit, unsigned int, resource,
1423 struct rlimit __user *, rlim)
1426 if (resource >= RLIM_NLIMITS)
1429 task_lock(current->group_leader);
1430 x = current->signal->rlim[resource];
1431 task_unlock(current->group_leader);
1432 if (x.rlim_cur > 0x7FFFFFFF)
1433 x.rlim_cur = 0x7FFFFFFF;
1434 if (x.rlim_max > 0x7FFFFFFF)
1435 x.rlim_max = 0x7FFFFFFF;
1436 return copy_to_user(rlim, &x, sizeof(x))?-EFAULT:0;
1441 SYSCALL_DEFINE2(setrlimit, unsigned int, resource, struct rlimit __user *, rlim)
1443 struct rlimit new_rlim, *old_rlim;
1446 if (resource >= RLIM_NLIMITS)
1448 if (copy_from_user(&new_rlim, rlim, sizeof(*rlim)))
1450 old_rlim = current->signal->rlim + resource;
1451 if ((new_rlim.rlim_max > old_rlim->rlim_max) &&
1452 !capable(CAP_SYS_RESOURCE))
1455 if (resource == RLIMIT_NOFILE) {
1456 if (new_rlim.rlim_max == RLIM_INFINITY)
1457 new_rlim.rlim_max = sysctl_nr_open;
1458 if (new_rlim.rlim_cur == RLIM_INFINITY)
1459 new_rlim.rlim_cur = sysctl_nr_open;
1460 if (new_rlim.rlim_max > sysctl_nr_open)
1464 if (new_rlim.rlim_cur > new_rlim.rlim_max)
1467 retval = security_task_setrlimit(resource, &new_rlim);
1471 if (resource == RLIMIT_CPU && new_rlim.rlim_cur == 0) {
1473 * The caller is asking for an immediate RLIMIT_CPU
1474 * expiry. But we use the zero value to mean "it was
1475 * never set". So let's cheat and make it one second
1478 new_rlim.rlim_cur = 1;
1481 task_lock(current->group_leader);
1482 *old_rlim = new_rlim;
1483 task_unlock(current->group_leader);
1485 if (resource != RLIMIT_CPU)
1489 * RLIMIT_CPU handling. Note that the kernel fails to return an error
1490 * code if it rejected the user's attempt to set RLIMIT_CPU. This is a
1491 * very long-standing error, and fixing it now risks breakage of
1492 * applications, so we live with it
1494 if (new_rlim.rlim_cur == RLIM_INFINITY)
1497 update_rlimit_cpu(new_rlim.rlim_cur);
1503 * It would make sense to put struct rusage in the task_struct,
1504 * except that would make the task_struct be *really big*. After
1505 * task_struct gets moved into malloc'ed memory, it would
1506 * make sense to do this. It will make moving the rest of the information
1507 * a lot simpler! (Which we're not doing right now because we're not
1508 * measuring them yet).
1510 * When sampling multiple threads for RUSAGE_SELF, under SMP we might have
1511 * races with threads incrementing their own counters. But since word
1512 * reads are atomic, we either get new values or old values and we don't
1513 * care which for the sums. We always take the siglock to protect reading
1514 * the c* fields from p->signal from races with exit.c updating those
1515 * fields when reaping, so a sample either gets all the additions of a
1516 * given child after it's reaped, or none so this sample is before reaping.
1519 * We need to take the siglock for CHILDEREN, SELF and BOTH
1520 * for the cases current multithreaded, non-current single threaded
1521 * non-current multithreaded. Thread traversal is now safe with
1523 * Strictly speaking, we donot need to take the siglock if we are current and
1524 * single threaded, as no one else can take our signal_struct away, no one
1525 * else can reap the children to update signal->c* counters, and no one else
1526 * can race with the signal-> fields. If we do not take any lock, the
1527 * signal-> fields could be read out of order while another thread was just
1528 * exiting. So we should place a read memory barrier when we avoid the lock.
1529 * On the writer side, write memory barrier is implied in __exit_signal
1530 * as __exit_signal releases the siglock spinlock after updating the signal->
1531 * fields. But we don't do this yet to keep things simple.
1535 static void accumulate_thread_rusage(struct task_struct *t, struct rusage *r)
1537 r->ru_nvcsw += t->nvcsw;
1538 r->ru_nivcsw += t->nivcsw;
1539 r->ru_minflt += t->min_flt;
1540 r->ru_majflt += t->maj_flt;
1541 r->ru_inblock += task_io_get_inblock(t);
1542 r->ru_oublock += task_io_get_oublock(t);
1545 static void k_getrusage(struct task_struct *p, int who, struct rusage *r)
1547 struct task_struct *t;
1548 unsigned long flags;
1549 cputime_t utime, stime;
1550 struct task_cputime cputime;
1552 memset((char *) r, 0, sizeof *r);
1553 utime = stime = cputime_zero;
1555 if (who == RUSAGE_THREAD) {
1556 accumulate_thread_rusage(p, r);
1560 if (!lock_task_sighand(p, &flags))
1565 case RUSAGE_CHILDREN:
1566 utime = p->signal->cutime;
1567 stime = p->signal->cstime;
1568 r->ru_nvcsw = p->signal->cnvcsw;
1569 r->ru_nivcsw = p->signal->cnivcsw;
1570 r->ru_minflt = p->signal->cmin_flt;
1571 r->ru_majflt = p->signal->cmaj_flt;
1572 r->ru_inblock = p->signal->cinblock;
1573 r->ru_oublock = p->signal->coublock;
1575 if (who == RUSAGE_CHILDREN)
1579 thread_group_cputime(p, &cputime);
1580 utime = cputime_add(utime, cputime.utime);
1581 stime = cputime_add(stime, cputime.stime);
1582 r->ru_nvcsw += p->signal->nvcsw;
1583 r->ru_nivcsw += p->signal->nivcsw;
1584 r->ru_minflt += p->signal->min_flt;
1585 r->ru_majflt += p->signal->maj_flt;
1586 r->ru_inblock += p->signal->inblock;
1587 r->ru_oublock += p->signal->oublock;
1590 accumulate_thread_rusage(t, r);
1598 unlock_task_sighand(p, &flags);
1601 cputime_to_timeval(utime, &r->ru_utime);
1602 cputime_to_timeval(stime, &r->ru_stime);
1605 int getrusage(struct task_struct *p, int who, struct rusage __user *ru)
1608 k_getrusage(p, who, &r);
1609 return copy_to_user(ru, &r, sizeof(r)) ? -EFAULT : 0;
1612 SYSCALL_DEFINE2(getrusage, int, who, struct rusage __user *, ru)
1614 if (who != RUSAGE_SELF && who != RUSAGE_CHILDREN &&
1615 who != RUSAGE_THREAD)
1617 return getrusage(current, who, ru);
1620 SYSCALL_DEFINE1(umask, int, mask)
1622 mask = xchg(¤t->fs->umask, mask & S_IRWXUGO);
1626 asmlinkage long sys_prctl(int option, unsigned long arg2, unsigned long arg3,
1627 unsigned long arg4, unsigned long arg5)
1631 if (security_task_prctl(option, arg2, arg3, arg4, arg5, &error))
1635 case PR_SET_PDEATHSIG:
1636 if (!valid_signal(arg2)) {
1640 current->pdeath_signal = arg2;
1642 case PR_GET_PDEATHSIG:
1643 error = put_user(current->pdeath_signal, (int __user *)arg2);
1645 case PR_GET_DUMPABLE:
1646 error = get_dumpable(current->mm);
1648 case PR_SET_DUMPABLE:
1649 if (arg2 < 0 || arg2 > 1) {
1653 set_dumpable(current->mm, arg2);
1656 case PR_SET_UNALIGN:
1657 error = SET_UNALIGN_CTL(current, arg2);
1659 case PR_GET_UNALIGN:
1660 error = GET_UNALIGN_CTL(current, arg2);
1663 error = SET_FPEMU_CTL(current, arg2);
1666 error = GET_FPEMU_CTL(current, arg2);
1669 error = SET_FPEXC_CTL(current, arg2);
1672 error = GET_FPEXC_CTL(current, arg2);
1675 error = PR_TIMING_STATISTICAL;
1678 if (arg2 != PR_TIMING_STATISTICAL)
1683 struct task_struct *me = current;
1684 unsigned char ncomm[sizeof(me->comm)];
1686 ncomm[sizeof(me->comm)-1] = 0;
1687 if (strncpy_from_user(ncomm, (char __user *)arg2,
1688 sizeof(me->comm)-1) < 0)
1690 set_task_comm(me, ncomm);
1694 struct task_struct *me = current;
1695 unsigned char tcomm[sizeof(me->comm)];
1697 get_task_comm(tcomm, me);
1698 if (copy_to_user((char __user *)arg2, tcomm, sizeof(tcomm)))
1703 error = GET_ENDIAN(current, arg2);
1706 error = SET_ENDIAN(current, arg2);
1709 case PR_GET_SECCOMP:
1710 error = prctl_get_seccomp();
1712 case PR_SET_SECCOMP:
1713 error = prctl_set_seccomp(arg2);
1716 error = GET_TSC_CTL(arg2);
1719 error = SET_TSC_CTL(arg2);
1721 case PR_GET_TIMERSLACK:
1722 error = current->timer_slack_ns;
1724 case PR_SET_TIMERSLACK:
1726 current->timer_slack_ns =
1727 current->default_timer_slack_ns;
1729 current->timer_slack_ns = arg2;
1738 asmlinkage long sys_getcpu(unsigned __user *cpup, unsigned __user *nodep,
1739 struct getcpu_cache __user *unused)
1742 int cpu = raw_smp_processor_id();
1744 err |= put_user(cpu, cpup);
1746 err |= put_user(cpu_to_node(cpu), nodep);
1747 return err ? -EFAULT : 0;
1750 char poweroff_cmd[POWEROFF_CMD_PATH_LEN] = "/sbin/poweroff";
1752 static void argv_cleanup(char **argv, char **envp)
1758 * orderly_poweroff - Trigger an orderly system poweroff
1759 * @force: force poweroff if command execution fails
1761 * This may be called from any context to trigger a system shutdown.
1762 * If the orderly shutdown fails, it will force an immediate shutdown.
1764 int orderly_poweroff(bool force)
1767 char **argv = argv_split(GFP_ATOMIC, poweroff_cmd, &argc);
1768 static char *envp[] = {
1770 "PATH=/sbin:/bin:/usr/sbin:/usr/bin",
1774 struct subprocess_info *info;
1777 printk(KERN_WARNING "%s failed to allocate memory for \"%s\"\n",
1778 __func__, poweroff_cmd);
1782 info = call_usermodehelper_setup(argv[0], argv, envp, GFP_ATOMIC);
1788 call_usermodehelper_setcleanup(info, argv_cleanup);
1790 ret = call_usermodehelper_exec(info, UMH_NO_WAIT);
1794 printk(KERN_WARNING "Failed to start orderly shutdown: "
1795 "forcing the issue\n");
1797 /* I guess this should try to kick off some daemon to
1798 sync and poweroff asap. Or not even bother syncing
1799 if we're doing an emergency shutdown? */
1806 EXPORT_SYMBOL_GPL(orderly_poweroff);