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 asmlinkage long sys_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_task(pgrp, PIDTYPE_PGID, p) {
173 error = set_one_prio(p, niceval, error);
174 } while_each_pid_task(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 asmlinkage long sys_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_task(pgrp, PIDTYPE_PGID, p) {
233 niceval = 20 - task_nice(p);
234 if (niceval > retval)
236 } while_each_pid_task(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 static 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);
305 * kernel_kexec - reboot the system
307 * Move into place and start executing a preloaded standalone
308 * executable. If nothing was preloaded return an error.
310 static void kernel_kexec(void)
313 struct kimage *image;
314 image = xchg(&kexec_image, NULL);
317 kernel_restart_prepare(NULL);
318 printk(KERN_EMERG "Starting new kernel\n");
320 machine_kexec(image);
324 static void kernel_shutdown_prepare(enum system_states state)
326 blocking_notifier_call_chain(&reboot_notifier_list,
327 (state == SYSTEM_HALT)?SYS_HALT:SYS_POWER_OFF, NULL);
328 system_state = state;
332 * kernel_halt - halt the system
334 * Shutdown everything and perform a clean system halt.
336 void kernel_halt(void)
338 kernel_shutdown_prepare(SYSTEM_HALT);
340 printk(KERN_EMERG "System halted.\n");
344 EXPORT_SYMBOL_GPL(kernel_halt);
347 * kernel_power_off - power_off the system
349 * Shutdown everything and perform a clean system power_off.
351 void kernel_power_off(void)
353 kernel_shutdown_prepare(SYSTEM_POWER_OFF);
354 if (pm_power_off_prepare)
355 pm_power_off_prepare();
356 disable_nonboot_cpus();
358 printk(KERN_EMERG "Power down.\n");
361 EXPORT_SYMBOL_GPL(kernel_power_off);
363 * Reboot system call: for obvious reasons only root may call it,
364 * and even root needs to set up some magic numbers in the registers
365 * so that some mistake won't make this reboot the whole machine.
366 * You can also set the meaning of the ctrl-alt-del-key here.
368 * reboot doesn't sync: do that yourself before calling this.
370 asmlinkage long sys_reboot(int magic1, int magic2, unsigned int cmd, void __user * arg)
374 /* We only trust the superuser with rebooting the system. */
375 if (!capable(CAP_SYS_BOOT))
378 /* For safety, we require "magic" arguments. */
379 if (magic1 != LINUX_REBOOT_MAGIC1 ||
380 (magic2 != LINUX_REBOOT_MAGIC2 &&
381 magic2 != LINUX_REBOOT_MAGIC2A &&
382 magic2 != LINUX_REBOOT_MAGIC2B &&
383 magic2 != LINUX_REBOOT_MAGIC2C))
386 /* Instead of trying to make the power_off code look like
387 * halt when pm_power_off is not set do it the easy way.
389 if ((cmd == LINUX_REBOOT_CMD_POWER_OFF) && !pm_power_off)
390 cmd = LINUX_REBOOT_CMD_HALT;
394 case LINUX_REBOOT_CMD_RESTART:
395 kernel_restart(NULL);
398 case LINUX_REBOOT_CMD_CAD_ON:
402 case LINUX_REBOOT_CMD_CAD_OFF:
406 case LINUX_REBOOT_CMD_HALT:
412 case LINUX_REBOOT_CMD_POWER_OFF:
418 case LINUX_REBOOT_CMD_RESTART2:
419 if (strncpy_from_user(&buffer[0], arg, sizeof(buffer) - 1) < 0) {
423 buffer[sizeof(buffer) - 1] = '\0';
425 kernel_restart(buffer);
428 case LINUX_REBOOT_CMD_KEXEC:
433 #ifdef CONFIG_HIBERNATION
434 case LINUX_REBOOT_CMD_SW_SUSPEND:
436 int ret = hibernate();
450 static void deferred_cad(struct work_struct *dummy)
452 kernel_restart(NULL);
456 * This function gets called by ctrl-alt-del - ie the keyboard interrupt.
457 * As it's called within an interrupt, it may NOT sync: the only choice
458 * is whether to reboot at once, or just ignore the ctrl-alt-del.
460 void ctrl_alt_del(void)
462 static DECLARE_WORK(cad_work, deferred_cad);
465 schedule_work(&cad_work);
467 kill_cad_pid(SIGINT, 1);
471 * Unprivileged users may change the real gid to the effective gid
472 * or vice versa. (BSD-style)
474 * If you set the real gid at all, or set the effective gid to a value not
475 * equal to the real gid, then the saved gid is set to the new effective gid.
477 * This makes it possible for a setgid program to completely drop its
478 * privileges, which is often a useful assertion to make when you are doing
479 * a security audit over a program.
481 * The general idea is that a program which uses just setregid() will be
482 * 100% compatible with BSD. A program which uses just setgid() will be
483 * 100% compatible with POSIX with saved IDs.
485 * SMP: There are not races, the GIDs are checked only by filesystem
486 * operations (as far as semantic preservation is concerned).
488 asmlinkage long sys_setregid(gid_t rgid, gid_t egid)
490 int old_rgid = current->gid;
491 int old_egid = current->egid;
492 int new_rgid = old_rgid;
493 int new_egid = old_egid;
496 retval = security_task_setgid(rgid, egid, (gid_t)-1, LSM_SETID_RE);
500 if (rgid != (gid_t) -1) {
501 if ((old_rgid == rgid) ||
502 (current->egid==rgid) ||
508 if (egid != (gid_t) -1) {
509 if ((old_rgid == egid) ||
510 (current->egid == egid) ||
511 (current->sgid == egid) ||
517 if (new_egid != old_egid) {
518 set_dumpable(current->mm, suid_dumpable);
521 if (rgid != (gid_t) -1 ||
522 (egid != (gid_t) -1 && egid != old_rgid))
523 current->sgid = new_egid;
524 current->fsgid = new_egid;
525 current->egid = new_egid;
526 current->gid = new_rgid;
527 key_fsgid_changed(current);
528 proc_id_connector(current, PROC_EVENT_GID);
533 * setgid() is implemented like SysV w/ SAVED_IDS
535 * SMP: Same implicit races as above.
537 asmlinkage long sys_setgid(gid_t gid)
539 int old_egid = current->egid;
542 retval = security_task_setgid(gid, (gid_t)-1, (gid_t)-1, LSM_SETID_ID);
546 if (capable(CAP_SETGID)) {
547 if (old_egid != gid) {
548 set_dumpable(current->mm, suid_dumpable);
551 current->gid = current->egid = current->sgid = current->fsgid = gid;
552 } else if ((gid == current->gid) || (gid == current->sgid)) {
553 if (old_egid != gid) {
554 set_dumpable(current->mm, suid_dumpable);
557 current->egid = current->fsgid = gid;
562 key_fsgid_changed(current);
563 proc_id_connector(current, PROC_EVENT_GID);
567 static int set_user(uid_t new_ruid, int dumpclear)
569 struct user_struct *new_user;
571 new_user = alloc_uid(current->nsproxy->user_ns, new_ruid);
575 if (atomic_read(&new_user->processes) >=
576 current->signal->rlim[RLIMIT_NPROC].rlim_cur &&
577 new_user != current->nsproxy->user_ns->root_user) {
582 switch_uid(new_user);
585 set_dumpable(current->mm, suid_dumpable);
588 current->uid = new_ruid;
593 * Unprivileged users may change the real uid to the effective uid
594 * or vice versa. (BSD-style)
596 * If you set the real uid at all, or set the effective uid to a value not
597 * equal to the real uid, then the saved uid is set to the new effective uid.
599 * This makes it possible for a setuid program to completely drop its
600 * privileges, which is often a useful assertion to make when you are doing
601 * a security audit over a program.
603 * The general idea is that a program which uses just setreuid() will be
604 * 100% compatible with BSD. A program which uses just setuid() will be
605 * 100% compatible with POSIX with saved IDs.
607 asmlinkage long sys_setreuid(uid_t ruid, uid_t euid)
609 int old_ruid, old_euid, old_suid, new_ruid, new_euid;
612 retval = security_task_setuid(ruid, euid, (uid_t)-1, LSM_SETID_RE);
616 new_ruid = old_ruid = current->uid;
617 new_euid = old_euid = current->euid;
618 old_suid = current->suid;
620 if (ruid != (uid_t) -1) {
622 if ((old_ruid != ruid) &&
623 (current->euid != ruid) &&
624 !capable(CAP_SETUID))
628 if (euid != (uid_t) -1) {
630 if ((old_ruid != euid) &&
631 (current->euid != euid) &&
632 (current->suid != euid) &&
633 !capable(CAP_SETUID))
637 if (new_ruid != old_ruid && set_user(new_ruid, new_euid != old_euid) < 0)
640 if (new_euid != old_euid) {
641 set_dumpable(current->mm, suid_dumpable);
644 current->fsuid = current->euid = new_euid;
645 if (ruid != (uid_t) -1 ||
646 (euid != (uid_t) -1 && euid != old_ruid))
647 current->suid = current->euid;
648 current->fsuid = current->euid;
650 key_fsuid_changed(current);
651 proc_id_connector(current, PROC_EVENT_UID);
653 return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_RE);
659 * setuid() is implemented like SysV with SAVED_IDS
661 * Note that SAVED_ID's is deficient in that a setuid root program
662 * like sendmail, for example, cannot set its uid to be a normal
663 * user and then switch back, because if you're root, setuid() sets
664 * the saved uid too. If you don't like this, blame the bright people
665 * in the POSIX committee and/or USG. Note that the BSD-style setreuid()
666 * will allow a root program to temporarily drop privileges and be able to
667 * regain them by swapping the real and effective uid.
669 asmlinkage long sys_setuid(uid_t uid)
671 int old_euid = current->euid;
672 int old_ruid, old_suid, new_suid;
675 retval = security_task_setuid(uid, (uid_t)-1, (uid_t)-1, LSM_SETID_ID);
679 old_ruid = current->uid;
680 old_suid = current->suid;
683 if (capable(CAP_SETUID)) {
684 if (uid != old_ruid && set_user(uid, old_euid != uid) < 0)
687 } else if ((uid != current->uid) && (uid != new_suid))
690 if (old_euid != uid) {
691 set_dumpable(current->mm, suid_dumpable);
694 current->fsuid = current->euid = uid;
695 current->suid = new_suid;
697 key_fsuid_changed(current);
698 proc_id_connector(current, PROC_EVENT_UID);
700 return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_ID);
705 * This function implements a generic ability to update ruid, euid,
706 * and suid. This allows you to implement the 4.4 compatible seteuid().
708 asmlinkage long sys_setresuid(uid_t ruid, uid_t euid, uid_t suid)
710 int old_ruid = current->uid;
711 int old_euid = current->euid;
712 int old_suid = current->suid;
715 retval = security_task_setuid(ruid, euid, suid, LSM_SETID_RES);
719 if (!capable(CAP_SETUID)) {
720 if ((ruid != (uid_t) -1) && (ruid != current->uid) &&
721 (ruid != current->euid) && (ruid != current->suid))
723 if ((euid != (uid_t) -1) && (euid != current->uid) &&
724 (euid != current->euid) && (euid != current->suid))
726 if ((suid != (uid_t) -1) && (suid != current->uid) &&
727 (suid != current->euid) && (suid != current->suid))
730 if (ruid != (uid_t) -1) {
731 if (ruid != current->uid && set_user(ruid, euid != current->euid) < 0)
734 if (euid != (uid_t) -1) {
735 if (euid != current->euid) {
736 set_dumpable(current->mm, suid_dumpable);
739 current->euid = euid;
741 current->fsuid = current->euid;
742 if (suid != (uid_t) -1)
743 current->suid = suid;
745 key_fsuid_changed(current);
746 proc_id_connector(current, PROC_EVENT_UID);
748 return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_RES);
751 asmlinkage long sys_getresuid(uid_t __user *ruid, uid_t __user *euid, uid_t __user *suid)
755 if (!(retval = put_user(current->uid, ruid)) &&
756 !(retval = put_user(current->euid, euid)))
757 retval = put_user(current->suid, suid);
763 * Same as above, but for rgid, egid, sgid.
765 asmlinkage long sys_setresgid(gid_t rgid, gid_t egid, gid_t sgid)
769 retval = security_task_setgid(rgid, egid, sgid, LSM_SETID_RES);
773 if (!capable(CAP_SETGID)) {
774 if ((rgid != (gid_t) -1) && (rgid != current->gid) &&
775 (rgid != current->egid) && (rgid != current->sgid))
777 if ((egid != (gid_t) -1) && (egid != current->gid) &&
778 (egid != current->egid) && (egid != current->sgid))
780 if ((sgid != (gid_t) -1) && (sgid != current->gid) &&
781 (sgid != current->egid) && (sgid != current->sgid))
784 if (egid != (gid_t) -1) {
785 if (egid != current->egid) {
786 set_dumpable(current->mm, suid_dumpable);
789 current->egid = egid;
791 current->fsgid = current->egid;
792 if (rgid != (gid_t) -1)
794 if (sgid != (gid_t) -1)
795 current->sgid = sgid;
797 key_fsgid_changed(current);
798 proc_id_connector(current, PROC_EVENT_GID);
802 asmlinkage long sys_getresgid(gid_t __user *rgid, gid_t __user *egid, gid_t __user *sgid)
806 if (!(retval = put_user(current->gid, rgid)) &&
807 !(retval = put_user(current->egid, egid)))
808 retval = put_user(current->sgid, sgid);
815 * "setfsuid()" sets the fsuid - the uid used for filesystem checks. This
816 * is used for "access()" and for the NFS daemon (letting nfsd stay at
817 * whatever uid it wants to). It normally shadows "euid", except when
818 * explicitly set by setfsuid() or for access..
820 asmlinkage long sys_setfsuid(uid_t uid)
824 old_fsuid = current->fsuid;
825 if (security_task_setuid(uid, (uid_t)-1, (uid_t)-1, LSM_SETID_FS))
828 if (uid == current->uid || uid == current->euid ||
829 uid == current->suid || uid == current->fsuid ||
830 capable(CAP_SETUID)) {
831 if (uid != old_fsuid) {
832 set_dumpable(current->mm, suid_dumpable);
835 current->fsuid = uid;
838 key_fsuid_changed(current);
839 proc_id_connector(current, PROC_EVENT_UID);
841 security_task_post_setuid(old_fsuid, (uid_t)-1, (uid_t)-1, LSM_SETID_FS);
847 * Samma på svenska..
849 asmlinkage long sys_setfsgid(gid_t gid)
853 old_fsgid = current->fsgid;
854 if (security_task_setgid(gid, (gid_t)-1, (gid_t)-1, LSM_SETID_FS))
857 if (gid == current->gid || gid == current->egid ||
858 gid == current->sgid || gid == current->fsgid ||
859 capable(CAP_SETGID)) {
860 if (gid != old_fsgid) {
861 set_dumpable(current->mm, suid_dumpable);
864 current->fsgid = gid;
865 key_fsgid_changed(current);
866 proc_id_connector(current, PROC_EVENT_GID);
871 asmlinkage long sys_times(struct tms __user * tbuf)
874 * In the SMP world we might just be unlucky and have one of
875 * the times increment as we use it. Since the value is an
876 * atomically safe type this is just fine. Conceptually its
877 * as if the syscall took an instant longer to occur.
881 struct task_struct *tsk = current;
882 struct task_struct *t;
883 cputime_t utime, stime, cutime, cstime;
885 spin_lock_irq(&tsk->sighand->siglock);
886 utime = tsk->signal->utime;
887 stime = tsk->signal->stime;
890 utime = cputime_add(utime, t->utime);
891 stime = cputime_add(stime, t->stime);
895 cutime = tsk->signal->cutime;
896 cstime = tsk->signal->cstime;
897 spin_unlock_irq(&tsk->sighand->siglock);
899 tmp.tms_utime = cputime_to_clock_t(utime);
900 tmp.tms_stime = cputime_to_clock_t(stime);
901 tmp.tms_cutime = cputime_to_clock_t(cutime);
902 tmp.tms_cstime = cputime_to_clock_t(cstime);
903 if (copy_to_user(tbuf, &tmp, sizeof(struct tms)))
906 return (long) jiffies_64_to_clock_t(get_jiffies_64());
910 * This needs some heavy checking ...
911 * I just haven't the stomach for it. I also don't fully
912 * understand sessions/pgrp etc. Let somebody who does explain it.
914 * OK, I think I have the protection semantics right.... this is really
915 * only important on a multi-user system anyway, to make sure one user
916 * can't send a signal to a process owned by another. -TYT, 12/12/91
918 * Auch. Had to add the 'did_exec' flag to conform completely to POSIX.
921 asmlinkage long sys_setpgid(pid_t pid, pid_t pgid)
923 struct task_struct *p;
924 struct task_struct *group_leader = current->group_leader;
929 pid = task_pid_vnr(group_leader);
935 /* From this point forward we keep holding onto the tasklist lock
936 * so that our parent does not change from under us. -DaveM
938 write_lock_irq(&tasklist_lock);
941 p = find_task_by_vpid(pid);
946 if (!thread_group_leader(p))
949 if (same_thread_group(p->real_parent, group_leader)) {
951 if (task_session(p) != task_session(group_leader))
958 if (p != group_leader)
963 if (p->signal->leader)
968 struct task_struct *g;
970 pgrp = find_vpid(pgid);
971 g = pid_task(pgrp, PIDTYPE_PGID);
972 if (!g || task_session(g) != task_session(group_leader))
976 err = security_task_setpgid(p, pgid);
980 if (task_pgrp(p) != pgrp) {
981 change_pid(p, PIDTYPE_PGID, pgrp);
982 set_task_pgrp(p, pid_nr(pgrp));
987 /* All paths lead to here, thus we are safe. -DaveM */
988 write_unlock_irq(&tasklist_lock);
992 asmlinkage long sys_getpgid(pid_t pid)
994 struct task_struct *p;
1000 grp = task_pgrp(current);
1003 p = find_task_by_vpid(pid);
1010 retval = security_task_getpgid(p);
1014 retval = pid_vnr(grp);
1020 #ifdef __ARCH_WANT_SYS_GETPGRP
1022 asmlinkage long sys_getpgrp(void)
1024 return sys_getpgid(0);
1029 asmlinkage long sys_getsid(pid_t pid)
1031 struct task_struct *p;
1037 sid = task_session(current);
1040 p = find_task_by_vpid(pid);
1043 sid = task_session(p);
1047 retval = security_task_getsid(p);
1051 retval = pid_vnr(sid);
1057 asmlinkage long sys_setsid(void)
1059 struct task_struct *group_leader = current->group_leader;
1060 struct pid *sid = task_pid(group_leader);
1061 pid_t session = pid_vnr(sid);
1064 write_lock_irq(&tasklist_lock);
1065 /* Fail if I am already a session leader */
1066 if (group_leader->signal->leader)
1069 /* Fail if a process group id already exists that equals the
1070 * proposed session id.
1072 if (pid_task(sid, PIDTYPE_PGID))
1075 group_leader->signal->leader = 1;
1076 __set_special_pids(sid);
1078 spin_lock(&group_leader->sighand->siglock);
1079 group_leader->signal->tty = NULL;
1080 spin_unlock(&group_leader->sighand->siglock);
1084 write_unlock_irq(&tasklist_lock);
1089 * Supplementary group IDs
1092 /* init to 2 - one for init_task, one to ensure it is never freed */
1093 struct group_info init_groups = { .usage = ATOMIC_INIT(2) };
1095 struct group_info *groups_alloc(int gidsetsize)
1097 struct group_info *group_info;
1101 nblocks = (gidsetsize + NGROUPS_PER_BLOCK - 1) / NGROUPS_PER_BLOCK;
1102 /* Make sure we always allocate at least one indirect block pointer */
1103 nblocks = nblocks ? : 1;
1104 group_info = kmalloc(sizeof(*group_info) + nblocks*sizeof(gid_t *), GFP_USER);
1107 group_info->ngroups = gidsetsize;
1108 group_info->nblocks = nblocks;
1109 atomic_set(&group_info->usage, 1);
1111 if (gidsetsize <= NGROUPS_SMALL)
1112 group_info->blocks[0] = group_info->small_block;
1114 for (i = 0; i < nblocks; i++) {
1116 b = (void *)__get_free_page(GFP_USER);
1118 goto out_undo_partial_alloc;
1119 group_info->blocks[i] = b;
1124 out_undo_partial_alloc:
1126 free_page((unsigned long)group_info->blocks[i]);
1132 EXPORT_SYMBOL(groups_alloc);
1134 void groups_free(struct group_info *group_info)
1136 if (group_info->blocks[0] != group_info->small_block) {
1138 for (i = 0; i < group_info->nblocks; i++)
1139 free_page((unsigned long)group_info->blocks[i]);
1144 EXPORT_SYMBOL(groups_free);
1146 /* export the group_info to a user-space array */
1147 static int groups_to_user(gid_t __user *grouplist,
1148 struct group_info *group_info)
1151 unsigned int count = group_info->ngroups;
1153 for (i = 0; i < group_info->nblocks; i++) {
1154 unsigned int cp_count = min(NGROUPS_PER_BLOCK, count);
1155 unsigned int len = cp_count * sizeof(*grouplist);
1157 if (copy_to_user(grouplist, group_info->blocks[i], len))
1160 grouplist += NGROUPS_PER_BLOCK;
1166 /* fill a group_info from a user-space array - it must be allocated already */
1167 static int groups_from_user(struct group_info *group_info,
1168 gid_t __user *grouplist)
1171 unsigned int count = group_info->ngroups;
1173 for (i = 0; i < group_info->nblocks; i++) {
1174 unsigned int cp_count = min(NGROUPS_PER_BLOCK, count);
1175 unsigned int len = cp_count * sizeof(*grouplist);
1177 if (copy_from_user(group_info->blocks[i], grouplist, len))
1180 grouplist += NGROUPS_PER_BLOCK;
1186 /* a simple Shell sort */
1187 static void groups_sort(struct group_info *group_info)
1189 int base, max, stride;
1190 int gidsetsize = group_info->ngroups;
1192 for (stride = 1; stride < gidsetsize; stride = 3 * stride + 1)
1197 max = gidsetsize - stride;
1198 for (base = 0; base < max; base++) {
1200 int right = left + stride;
1201 gid_t tmp = GROUP_AT(group_info, right);
1203 while (left >= 0 && GROUP_AT(group_info, left) > tmp) {
1204 GROUP_AT(group_info, right) =
1205 GROUP_AT(group_info, left);
1209 GROUP_AT(group_info, right) = tmp;
1215 /* a simple bsearch */
1216 int groups_search(struct group_info *group_info, gid_t grp)
1218 unsigned int left, right;
1224 right = group_info->ngroups;
1225 while (left < right) {
1226 unsigned int mid = (left+right)/2;
1227 int cmp = grp - GROUP_AT(group_info, mid);
1238 /* validate and set current->group_info */
1239 int set_current_groups(struct group_info *group_info)
1242 struct group_info *old_info;
1244 retval = security_task_setgroups(group_info);
1248 groups_sort(group_info);
1249 get_group_info(group_info);
1252 old_info = current->group_info;
1253 current->group_info = group_info;
1254 task_unlock(current);
1256 put_group_info(old_info);
1261 EXPORT_SYMBOL(set_current_groups);
1263 asmlinkage long sys_getgroups(int gidsetsize, gid_t __user *grouplist)
1268 * SMP: Nobody else can change our grouplist. Thus we are
1275 /* no need to grab task_lock here; it cannot change */
1276 i = current->group_info->ngroups;
1278 if (i > gidsetsize) {
1282 if (groups_to_user(grouplist, current->group_info)) {
1292 * SMP: Our groups are copy-on-write. We can set them safely
1293 * without another task interfering.
1296 asmlinkage long sys_setgroups(int gidsetsize, gid_t __user *grouplist)
1298 struct group_info *group_info;
1301 if (!capable(CAP_SETGID))
1303 if ((unsigned)gidsetsize > NGROUPS_MAX)
1306 group_info = groups_alloc(gidsetsize);
1309 retval = groups_from_user(group_info, grouplist);
1311 put_group_info(group_info);
1315 retval = set_current_groups(group_info);
1316 put_group_info(group_info);
1322 * Check whether we're fsgid/egid or in the supplemental group..
1324 int in_group_p(gid_t grp)
1327 if (grp != current->fsgid)
1328 retval = groups_search(current->group_info, grp);
1332 EXPORT_SYMBOL(in_group_p);
1334 int in_egroup_p(gid_t grp)
1337 if (grp != current->egid)
1338 retval = groups_search(current->group_info, grp);
1342 EXPORT_SYMBOL(in_egroup_p);
1344 DECLARE_RWSEM(uts_sem);
1346 asmlinkage long sys_newuname(struct new_utsname __user * name)
1350 down_read(&uts_sem);
1351 if (copy_to_user(name, utsname(), sizeof *name))
1357 asmlinkage long sys_sethostname(char __user *name, int len)
1360 char tmp[__NEW_UTS_LEN];
1362 if (!capable(CAP_SYS_ADMIN))
1364 if (len < 0 || len > __NEW_UTS_LEN)
1366 down_write(&uts_sem);
1368 if (!copy_from_user(tmp, name, len)) {
1369 memcpy(utsname()->nodename, tmp, len);
1370 utsname()->nodename[len] = 0;
1377 #ifdef __ARCH_WANT_SYS_GETHOSTNAME
1379 asmlinkage long sys_gethostname(char __user *name, int len)
1385 down_read(&uts_sem);
1386 i = 1 + strlen(utsname()->nodename);
1390 if (copy_to_user(name, utsname()->nodename, i))
1399 * Only setdomainname; getdomainname can be implemented by calling
1402 asmlinkage long sys_setdomainname(char __user *name, int len)
1405 char tmp[__NEW_UTS_LEN];
1407 if (!capable(CAP_SYS_ADMIN))
1409 if (len < 0 || len > __NEW_UTS_LEN)
1412 down_write(&uts_sem);
1414 if (!copy_from_user(tmp, name, len)) {
1415 memcpy(utsname()->domainname, tmp, len);
1416 utsname()->domainname[len] = 0;
1423 asmlinkage long sys_getrlimit(unsigned int resource, struct rlimit __user *rlim)
1425 if (resource >= RLIM_NLIMITS)
1428 struct rlimit value;
1429 task_lock(current->group_leader);
1430 value = current->signal->rlim[resource];
1431 task_unlock(current->group_leader);
1432 return copy_to_user(rlim, &value, sizeof(*rlim)) ? -EFAULT : 0;
1436 #ifdef __ARCH_WANT_SYS_OLD_GETRLIMIT
1439 * Back compatibility for getrlimit. Needed for some apps.
1442 asmlinkage long sys_old_getrlimit(unsigned int resource, struct rlimit __user *rlim)
1445 if (resource >= RLIM_NLIMITS)
1448 task_lock(current->group_leader);
1449 x = current->signal->rlim[resource];
1450 task_unlock(current->group_leader);
1451 if (x.rlim_cur > 0x7FFFFFFF)
1452 x.rlim_cur = 0x7FFFFFFF;
1453 if (x.rlim_max > 0x7FFFFFFF)
1454 x.rlim_max = 0x7FFFFFFF;
1455 return copy_to_user(rlim, &x, sizeof(x))?-EFAULT:0;
1460 asmlinkage long sys_setrlimit(unsigned int resource, struct rlimit __user *rlim)
1462 struct rlimit new_rlim, *old_rlim;
1463 unsigned long it_prof_secs;
1466 if (resource >= RLIM_NLIMITS)
1468 if (copy_from_user(&new_rlim, rlim, sizeof(*rlim)))
1470 if (new_rlim.rlim_cur > new_rlim.rlim_max)
1472 old_rlim = current->signal->rlim + resource;
1473 if ((new_rlim.rlim_max > old_rlim->rlim_max) &&
1474 !capable(CAP_SYS_RESOURCE))
1476 if (resource == RLIMIT_NOFILE && new_rlim.rlim_max > sysctl_nr_open)
1479 retval = security_task_setrlimit(resource, &new_rlim);
1483 if (resource == RLIMIT_CPU && new_rlim.rlim_cur == 0) {
1485 * The caller is asking for an immediate RLIMIT_CPU
1486 * expiry. But we use the zero value to mean "it was
1487 * never set". So let's cheat and make it one second
1490 new_rlim.rlim_cur = 1;
1493 task_lock(current->group_leader);
1494 *old_rlim = new_rlim;
1495 task_unlock(current->group_leader);
1497 if (resource != RLIMIT_CPU)
1501 * RLIMIT_CPU handling. Note that the kernel fails to return an error
1502 * code if it rejected the user's attempt to set RLIMIT_CPU. This is a
1503 * very long-standing error, and fixing it now risks breakage of
1504 * applications, so we live with it
1506 if (new_rlim.rlim_cur == RLIM_INFINITY)
1509 it_prof_secs = cputime_to_secs(current->signal->it_prof_expires);
1510 if (it_prof_secs == 0 || new_rlim.rlim_cur <= it_prof_secs) {
1511 unsigned long rlim_cur = new_rlim.rlim_cur;
1514 cputime = secs_to_cputime(rlim_cur);
1515 read_lock(&tasklist_lock);
1516 spin_lock_irq(¤t->sighand->siglock);
1517 set_process_cpu_timer(current, CPUCLOCK_PROF, &cputime, NULL);
1518 spin_unlock_irq(¤t->sighand->siglock);
1519 read_unlock(&tasklist_lock);
1526 * It would make sense to put struct rusage in the task_struct,
1527 * except that would make the task_struct be *really big*. After
1528 * task_struct gets moved into malloc'ed memory, it would
1529 * make sense to do this. It will make moving the rest of the information
1530 * a lot simpler! (Which we're not doing right now because we're not
1531 * measuring them yet).
1533 * When sampling multiple threads for RUSAGE_SELF, under SMP we might have
1534 * races with threads incrementing their own counters. But since word
1535 * reads are atomic, we either get new values or old values and we don't
1536 * care which for the sums. We always take the siglock to protect reading
1537 * the c* fields from p->signal from races with exit.c updating those
1538 * fields when reaping, so a sample either gets all the additions of a
1539 * given child after it's reaped, or none so this sample is before reaping.
1542 * We need to take the siglock for CHILDEREN, SELF and BOTH
1543 * for the cases current multithreaded, non-current single threaded
1544 * non-current multithreaded. Thread traversal is now safe with
1546 * Strictly speaking, we donot need to take the siglock if we are current and
1547 * single threaded, as no one else can take our signal_struct away, no one
1548 * else can reap the children to update signal->c* counters, and no one else
1549 * can race with the signal-> fields. If we do not take any lock, the
1550 * signal-> fields could be read out of order while another thread was just
1551 * exiting. So we should place a read memory barrier when we avoid the lock.
1552 * On the writer side, write memory barrier is implied in __exit_signal
1553 * as __exit_signal releases the siglock spinlock after updating the signal->
1554 * fields. But we don't do this yet to keep things simple.
1558 static void accumulate_thread_rusage(struct task_struct *t, struct rusage *r,
1559 cputime_t *utimep, cputime_t *stimep)
1561 *utimep = cputime_add(*utimep, t->utime);
1562 *stimep = cputime_add(*stimep, t->stime);
1563 r->ru_nvcsw += t->nvcsw;
1564 r->ru_nivcsw += t->nivcsw;
1565 r->ru_minflt += t->min_flt;
1566 r->ru_majflt += t->maj_flt;
1567 r->ru_inblock += task_io_get_inblock(t);
1568 r->ru_oublock += task_io_get_oublock(t);
1571 static void k_getrusage(struct task_struct *p, int who, struct rusage *r)
1573 struct task_struct *t;
1574 unsigned long flags;
1575 cputime_t utime, stime;
1577 memset((char *) r, 0, sizeof *r);
1578 utime = stime = cputime_zero;
1580 if (who == RUSAGE_THREAD) {
1581 accumulate_thread_rusage(p, r, &utime, &stime);
1585 if (!lock_task_sighand(p, &flags))
1590 case RUSAGE_CHILDREN:
1591 utime = p->signal->cutime;
1592 stime = p->signal->cstime;
1593 r->ru_nvcsw = p->signal->cnvcsw;
1594 r->ru_nivcsw = p->signal->cnivcsw;
1595 r->ru_minflt = p->signal->cmin_flt;
1596 r->ru_majflt = p->signal->cmaj_flt;
1597 r->ru_inblock = p->signal->cinblock;
1598 r->ru_oublock = p->signal->coublock;
1600 if (who == RUSAGE_CHILDREN)
1604 utime = cputime_add(utime, p->signal->utime);
1605 stime = cputime_add(stime, p->signal->stime);
1606 r->ru_nvcsw += p->signal->nvcsw;
1607 r->ru_nivcsw += p->signal->nivcsw;
1608 r->ru_minflt += p->signal->min_flt;
1609 r->ru_majflt += p->signal->maj_flt;
1610 r->ru_inblock += p->signal->inblock;
1611 r->ru_oublock += p->signal->oublock;
1614 accumulate_thread_rusage(t, r, &utime, &stime);
1622 unlock_task_sighand(p, &flags);
1625 cputime_to_timeval(utime, &r->ru_utime);
1626 cputime_to_timeval(stime, &r->ru_stime);
1629 int getrusage(struct task_struct *p, int who, struct rusage __user *ru)
1632 k_getrusage(p, who, &r);
1633 return copy_to_user(ru, &r, sizeof(r)) ? -EFAULT : 0;
1636 asmlinkage long sys_getrusage(int who, struct rusage __user *ru)
1638 if (who != RUSAGE_SELF && who != RUSAGE_CHILDREN &&
1639 who != RUSAGE_THREAD)
1641 return getrusage(current, who, ru);
1644 asmlinkage long sys_umask(int mask)
1646 mask = xchg(¤t->fs->umask, mask & S_IRWXUGO);
1650 asmlinkage long sys_prctl(int option, unsigned long arg2, unsigned long arg3,
1651 unsigned long arg4, unsigned long arg5)
1655 if (security_task_prctl(option, arg2, arg3, arg4, arg5, &error))
1659 case PR_SET_PDEATHSIG:
1660 if (!valid_signal(arg2)) {
1664 current->pdeath_signal = arg2;
1666 case PR_GET_PDEATHSIG:
1667 error = put_user(current->pdeath_signal, (int __user *)arg2);
1669 case PR_GET_DUMPABLE:
1670 error = get_dumpable(current->mm);
1672 case PR_SET_DUMPABLE:
1673 if (arg2 < 0 || arg2 > 1) {
1677 set_dumpable(current->mm, arg2);
1680 case PR_SET_UNALIGN:
1681 error = SET_UNALIGN_CTL(current, arg2);
1683 case PR_GET_UNALIGN:
1684 error = GET_UNALIGN_CTL(current, arg2);
1687 error = SET_FPEMU_CTL(current, arg2);
1690 error = GET_FPEMU_CTL(current, arg2);
1693 error = SET_FPEXC_CTL(current, arg2);
1696 error = GET_FPEXC_CTL(current, arg2);
1699 error = PR_TIMING_STATISTICAL;
1702 if (arg2 != PR_TIMING_STATISTICAL)
1707 struct task_struct *me = current;
1708 unsigned char ncomm[sizeof(me->comm)];
1710 ncomm[sizeof(me->comm)-1] = 0;
1711 if (strncpy_from_user(ncomm, (char __user *)arg2,
1712 sizeof(me->comm)-1) < 0)
1714 set_task_comm(me, ncomm);
1718 struct task_struct *me = current;
1719 unsigned char tcomm[sizeof(me->comm)];
1721 get_task_comm(tcomm, me);
1722 if (copy_to_user((char __user *)arg2, tcomm, sizeof(tcomm)))
1727 error = GET_ENDIAN(current, arg2);
1730 error = SET_ENDIAN(current, arg2);
1733 case PR_GET_SECCOMP:
1734 error = prctl_get_seccomp();
1736 case PR_SET_SECCOMP:
1737 error = prctl_set_seccomp(arg2);
1740 error = GET_TSC_CTL(arg2);
1743 error = SET_TSC_CTL(arg2);
1752 asmlinkage long sys_getcpu(unsigned __user *cpup, unsigned __user *nodep,
1753 struct getcpu_cache __user *unused)
1756 int cpu = raw_smp_processor_id();
1758 err |= put_user(cpu, cpup);
1760 err |= put_user(cpu_to_node(cpu), nodep);
1761 return err ? -EFAULT : 0;
1764 char poweroff_cmd[POWEROFF_CMD_PATH_LEN] = "/sbin/poweroff";
1766 static void argv_cleanup(char **argv, char **envp)
1772 * orderly_poweroff - Trigger an orderly system poweroff
1773 * @force: force poweroff if command execution fails
1775 * This may be called from any context to trigger a system shutdown.
1776 * If the orderly shutdown fails, it will force an immediate shutdown.
1778 int orderly_poweroff(bool force)
1781 char **argv = argv_split(GFP_ATOMIC, poweroff_cmd, &argc);
1782 static char *envp[] = {
1784 "PATH=/sbin:/bin:/usr/sbin:/usr/bin",
1788 struct subprocess_info *info;
1791 printk(KERN_WARNING "%s failed to allocate memory for \"%s\"\n",
1792 __func__, poweroff_cmd);
1796 info = call_usermodehelper_setup(argv[0], argv, envp, GFP_ATOMIC);
1802 call_usermodehelper_setcleanup(info, argv_cleanup);
1804 ret = call_usermodehelper_exec(info, UMH_NO_WAIT);
1808 printk(KERN_WARNING "Failed to start orderly shutdown: "
1809 "forcing the issue\n");
1811 /* I guess this should try to kick off some daemon to
1812 sync and poweroff asap. Or not even bother syncing
1813 if we're doing an emergency shutdown? */
1820 EXPORT_SYMBOL_GPL(orderly_poweroff);