diff options
Diffstat (limited to 'kernel/sys.c')
| -rw-r--r-- | kernel/sys.c | 1725 |
1 files changed, 1725 insertions, 0 deletions
diff --git a/kernel/sys.c b/kernel/sys.c new file mode 100644 index 0000000..462d78d5 --- /dev/null +++ b/kernel/sys.c @@ -0,0 +1,1725 @@ +/* + * linux/kernel/sys.c + * + * Copyright (C) 1991, 1992 Linus Torvalds + */ + +#include <linux/config.h> +#include <linux/module.h> +#include <linux/mm.h> +#include <linux/utsname.h> +#include <linux/mman.h> +#include <linux/smp_lock.h> +#include <linux/notifier.h> +#include <linux/reboot.h> +#include <linux/prctl.h> +#include <linux/init.h> +#include <linux/highuid.h> +#include <linux/fs.h> +#include <linux/workqueue.h> +#include <linux/device.h> +#include <linux/key.h> +#include <linux/times.h> +#include <linux/posix-timers.h> +#include <linux/security.h> +#include <linux/dcookies.h> +#include <linux/suspend.h> +#include <linux/tty.h> + +#include <linux/compat.h> +#include <linux/syscalls.h> + +#include <asm/uaccess.h> +#include <asm/io.h> +#include <asm/unistd.h> + +#ifndef SET_UNALIGN_CTL +# define SET_UNALIGN_CTL(a,b) (-EINVAL) +#endif +#ifndef GET_UNALIGN_CTL +# define GET_UNALIGN_CTL(a,b) (-EINVAL) +#endif +#ifndef SET_FPEMU_CTL +# define SET_FPEMU_CTL(a,b) (-EINVAL) +#endif +#ifndef GET_FPEMU_CTL +# define GET_FPEMU_CTL(a,b) (-EINVAL) +#endif +#ifndef SET_FPEXC_CTL +# define SET_FPEXC_CTL(a,b) (-EINVAL) +#endif +#ifndef GET_FPEXC_CTL +# define GET_FPEXC_CTL(a,b) (-EINVAL) +#endif + +/* + * this is where the system-wide overflow UID and GID are defined, for + * architectures that now have 32-bit UID/GID but didn't in the past + */ + +int overflowuid = DEFAULT_OVERFLOWUID; +int overflowgid = DEFAULT_OVERFLOWGID; + +#ifdef CONFIG_UID16 +EXPORT_SYMBOL(overflowuid); +EXPORT_SYMBOL(overflowgid); +#endif + +/* + * the same as above, but for filesystems which can only store a 16-bit + * UID and GID. as such, this is needed on all architectures + */ + +int fs_overflowuid = DEFAULT_FS_OVERFLOWUID; +int fs_overflowgid = DEFAULT_FS_OVERFLOWUID; + +EXPORT_SYMBOL(fs_overflowuid); +EXPORT_SYMBOL(fs_overflowgid); + +/* + * this indicates whether you can reboot with ctrl-alt-del: the default is yes + */ + +int C_A_D = 1; +int cad_pid = 1; + +/* + * Notifier list for kernel code which wants to be called + * at shutdown. This is used to stop any idling DMA operations + * and the like. + */ + +static struct notifier_block *reboot_notifier_list; +static DEFINE_RWLOCK(notifier_lock); + +/** + * notifier_chain_register - Add notifier to a notifier chain + * @list: Pointer to root list pointer + * @n: New entry in notifier chain + * + * Adds a notifier to a notifier chain. + * + * Currently always returns zero. + */ + +int notifier_chain_register(struct notifier_block **list, struct notifier_block *n) +{ + write_lock(¬ifier_lock); + while(*list) + { + if(n->priority > (*list)->priority) + break; + list= &((*list)->next); + } + n->next = *list; + *list=n; + write_unlock(¬ifier_lock); + return 0; +} + +EXPORT_SYMBOL(notifier_chain_register); + +/** + * notifier_chain_unregister - Remove notifier from a notifier chain + * @nl: Pointer to root list pointer + * @n: New entry in notifier chain + * + * Removes a notifier from a notifier chain. + * + * Returns zero on success, or %-ENOENT on failure. + */ + +int notifier_chain_unregister(struct notifier_block **nl, struct notifier_block *n) +{ + write_lock(¬ifier_lock); + while((*nl)!=NULL) + { + if((*nl)==n) + { + *nl=n->next; + write_unlock(¬ifier_lock); + return 0; + } + nl=&((*nl)->next); + } + write_unlock(¬ifier_lock); + return -ENOENT; +} + +EXPORT_SYMBOL(notifier_chain_unregister); + +/** + * notifier_call_chain - Call functions in a notifier chain + * @n: Pointer to root pointer of notifier chain + * @val: Value passed unmodified to notifier function + * @v: Pointer passed unmodified to notifier function + * + * Calls each function in a notifier chain in turn. + * + * If the return value of the notifier can be and'd + * with %NOTIFY_STOP_MASK, then notifier_call_chain + * will return immediately, with the return value of + * the notifier function which halted execution. + * Otherwise, the return value is the return value + * of the last notifier function called. + */ + +int notifier_call_chain(struct notifier_block **n, unsigned long val, void *v) +{ + int ret=NOTIFY_DONE; + struct notifier_block *nb = *n; + + while(nb) + { + ret=nb->notifier_call(nb,val,v); + if(ret&NOTIFY_STOP_MASK) + { + return ret; + } + nb=nb->next; + } + return ret; +} + +EXPORT_SYMBOL(notifier_call_chain); + +/** + * register_reboot_notifier - Register function to be called at reboot time + * @nb: Info about notifier function to be called + * + * Registers a function with the list of functions + * to be called at reboot time. + * + * Currently always returns zero, as notifier_chain_register + * always returns zero. + */ + +int register_reboot_notifier(struct notifier_block * nb) +{ + return notifier_chain_register(&reboot_notifier_list, nb); +} + +EXPORT_SYMBOL(register_reboot_notifier); + +/** + * unregister_reboot_notifier - Unregister previously registered reboot notifier + * @nb: Hook to be unregistered + * + * Unregisters a previously registered reboot + * notifier function. + * + * Returns zero on success, or %-ENOENT on failure. + */ + +int unregister_reboot_notifier(struct notifier_block * nb) +{ + return notifier_chain_unregister(&reboot_notifier_list, nb); +} + +EXPORT_SYMBOL(unregister_reboot_notifier); + +static int set_one_prio(struct task_struct *p, int niceval, int error) +{ + int no_nice; + + if (p->uid != current->euid && + p->euid != current->euid && !capable(CAP_SYS_NICE)) { + error = -EPERM; + goto out; + } + if (niceval < task_nice(p) && !capable(CAP_SYS_NICE)) { + error = -EACCES; + goto out; + } + no_nice = security_task_setnice(p, niceval); + if (no_nice) { + error = no_nice; + goto out; + } + if (error == -ESRCH) + error = 0; + set_user_nice(p, niceval); +out: + return error; +} + +asmlinkage long sys_setpriority(int which, int who, int niceval) +{ + struct task_struct *g, *p; + struct user_struct *user; + int error = -EINVAL; + + if (which > 2 || which < 0) + goto out; + + /* normalize: avoid signed division (rounding problems) */ + error = -ESRCH; + if (niceval < -20) + niceval = -20; + if (niceval > 19) + niceval = 19; + + read_lock(&tasklist_lock); + switch (which) { + case PRIO_PROCESS: + if (!who) + who = current->pid; + p = find_task_by_pid(who); + if (p) + error = set_one_prio(p, niceval, error); + break; + case PRIO_PGRP: + if (!who) + who = process_group(current); + do_each_task_pid(who, PIDTYPE_PGID, p) { + error = set_one_prio(p, niceval, error); + } while_each_task_pid(who, PIDTYPE_PGID, p); + break; + case PRIO_USER: + user = current->user; + if (!who) + who = current->uid; + else + if ((who != current->uid) && !(user = find_user(who))) + goto out_unlock; /* No processes for this user */ + + do_each_thread(g, p) + if (p->uid == who) + error = set_one_prio(p, niceval, error); + while_each_thread(g, p); + if (who != current->uid) + free_uid(user); /* For find_user() */ + break; + } +out_unlock: + read_unlock(&tasklist_lock); +out: + return error; +} + +/* + * Ugh. To avoid negative return values, "getpriority()" will + * not return the normal nice-value, but a negated value that + * has been offset by 20 (ie it returns 40..1 instead of -20..19) + * to stay compatible. + */ +asmlinkage long sys_getpriority(int which, int who) +{ + struct task_struct *g, *p; + struct user_struct *user; + long niceval, retval = -ESRCH; + + if (which > 2 || which < 0) + return -EINVAL; + + read_lock(&tasklist_lock); + switch (which) { + case PRIO_PROCESS: + if (!who) + who = current->pid; + p = find_task_by_pid(who); + if (p) { + niceval = 20 - task_nice(p); + if (niceval > retval) + retval = niceval; + } + break; + case PRIO_PGRP: + if (!who) + who = process_group(current); + do_each_task_pid(who, PIDTYPE_PGID, p) { + niceval = 20 - task_nice(p); + if (niceval > retval) + retval = niceval; + } while_each_task_pid(who, PIDTYPE_PGID, p); + break; + case PRIO_USER: + user = current->user; + if (!who) + who = current->uid; + else + if ((who != current->uid) && !(user = find_user(who))) + goto out_unlock; /* No processes for this user */ + + do_each_thread(g, p) + if (p->uid == who) { + niceval = 20 - task_nice(p); + if (niceval > retval) + retval = niceval; + } + while_each_thread(g, p); + if (who != current->uid) + free_uid(user); /* for find_user() */ + break; + } +out_unlock: + read_unlock(&tasklist_lock); + + return retval; +} + + +/* + * Reboot system call: for obvious reasons only root may call it, + * and even root needs to set up some magic numbers in the registers + * so that some mistake won't make this reboot the whole machine. + * You can also set the meaning of the ctrl-alt-del-key here. + * + * reboot doesn't sync: do that yourself before calling this. + */ +asmlinkage long sys_reboot(int magic1, int magic2, unsigned int cmd, void __user * arg) +{ + char buffer[256]; + + /* We only trust the superuser with rebooting the system. */ + if (!capable(CAP_SYS_BOOT)) + return -EPERM; + + /* For safety, we require "magic" arguments. */ + if (magic1 != LINUX_REBOOT_MAGIC1 || + (magic2 != LINUX_REBOOT_MAGIC2 && + magic2 != LINUX_REBOOT_MAGIC2A && + magic2 != LINUX_REBOOT_MAGIC2B && + magic2 != LINUX_REBOOT_MAGIC2C)) + return -EINVAL; + + lock_kernel(); + switch (cmd) { + case LINUX_REBOOT_CMD_RESTART: + notifier_call_chain(&reboot_notifier_list, SYS_RESTART, NULL); + system_state = SYSTEM_RESTART; + device_shutdown(); + printk(KERN_EMERG "Restarting system.\n"); + machine_restart(NULL); + break; + + case LINUX_REBOOT_CMD_CAD_ON: + C_A_D = 1; + break; + + case LINUX_REBOOT_CMD_CAD_OFF: + C_A_D = 0; + break; + + case LINUX_REBOOT_CMD_HALT: + notifier_call_chain(&reboot_notifier_list, SYS_HALT, NULL); + system_state = SYSTEM_HALT; + device_shutdown(); + printk(KERN_EMERG "System halted.\n"); + machine_halt(); + unlock_kernel(); + do_exit(0); + break; + + case LINUX_REBOOT_CMD_POWER_OFF: + notifier_call_chain(&reboot_notifier_list, SYS_POWER_OFF, NULL); + system_state = SYSTEM_POWER_OFF; + device_shutdown(); + printk(KERN_EMERG "Power down.\n"); + machine_power_off(); + unlock_kernel(); + do_exit(0); + break; + + case LINUX_REBOOT_CMD_RESTART2: + if (strncpy_from_user(&buffer[0], arg, sizeof(buffer) - 1) < 0) { + unlock_kernel(); + return -EFAULT; + } + buffer[sizeof(buffer) - 1] = '\0'; + + notifier_call_chain(&reboot_notifier_list, SYS_RESTART, buffer); + system_state = SYSTEM_RESTART; + device_shutdown(); + printk(KERN_EMERG "Restarting system with command '%s'.\n", buffer); + machine_restart(buffer); + break; + +#ifdef CONFIG_SOFTWARE_SUSPEND + case LINUX_REBOOT_CMD_SW_SUSPEND: + { + int ret = software_suspend(); + unlock_kernel(); + return ret; + } +#endif + + default: + unlock_kernel(); + return -EINVAL; + } + unlock_kernel(); + return 0; +} + +static void deferred_cad(void *dummy) +{ + notifier_call_chain(&reboot_notifier_list, SYS_RESTART, NULL); + machine_restart(NULL); +} + +/* + * This function gets called by ctrl-alt-del - ie the keyboard interrupt. + * As it's called within an interrupt, it may NOT sync: the only choice + * is whether to reboot at once, or just ignore the ctrl-alt-del. + */ +void ctrl_alt_del(void) +{ + static DECLARE_WORK(cad_work, deferred_cad, NULL); + + if (C_A_D) + schedule_work(&cad_work); + else + kill_proc(cad_pid, SIGINT, 1); +} + + +/* + * Unprivileged users may change the real gid to the effective gid + * or vice versa. (BSD-style) + * + * If you set the real gid at all, or set the effective gid to a value not + * equal to the real gid, then the saved gid is set to the new effective gid. + * + * This makes it possible for a setgid program to completely drop its + * privileges, which is often a useful assertion to make when you are doing + * a security audit over a program. + * + * The general idea is that a program which uses just setregid() will be + * 100% compatible with BSD. A program which uses just setgid() will be + * 100% compatible with POSIX with saved IDs. + * + * SMP: There are not races, the GIDs are checked only by filesystem + * operations (as far as semantic preservation is concerned). + */ +asmlinkage long sys_setregid(gid_t rgid, gid_t egid) +{ + int old_rgid = current->gid; + int old_egid = current->egid; + int new_rgid = old_rgid; + int new_egid = old_egid; + int retval; + + retval = security_task_setgid(rgid, egid, (gid_t)-1, LSM_SETID_RE); + if (retval) + return retval; + + if (rgid != (gid_t) -1) { + if ((old_rgid == rgid) || + (current->egid==rgid) || + capable(CAP_SETGID)) + new_rgid = rgid; + else + return -EPERM; + } + if (egid != (gid_t) -1) { + if ((old_rgid == egid) || + (current->egid == egid) || + (current->sgid == egid) || + capable(CAP_SETGID)) + new_egid = egid; + else { + return -EPERM; + } + } + if (new_egid != old_egid) + { + current->mm->dumpable = 0; + wmb(); + } + if (rgid != (gid_t) -1 || + (egid != (gid_t) -1 && egid != old_rgid)) + current->sgid = new_egid; + current->fsgid = new_egid; + current->egid = new_egid; + current->gid = new_rgid; + key_fsgid_changed(current); + return 0; +} + +/* + * setgid() is implemented like SysV w/ SAVED_IDS + * + * SMP: Same implicit races as above. + */ +asmlinkage long sys_setgid(gid_t gid) +{ + int old_egid = current->egid; + int retval; + + retval = security_task_setgid(gid, (gid_t)-1, (gid_t)-1, LSM_SETID_ID); + if (retval) + return retval; + + if (capable(CAP_SETGID)) + { + if(old_egid != gid) + { + current->mm->dumpable=0; + wmb(); + } + current->gid = current->egid = current->sgid = current->fsgid = gid; + } + else if ((gid == current->gid) || (gid == current->sgid)) + { + if(old_egid != gid) + { + current->mm->dumpable=0; + wmb(); + } + current->egid = current->fsgid = gid; + } + else + return -EPERM; + + key_fsgid_changed(current); + return 0; +} + +static int set_user(uid_t new_ruid, int dumpclear) +{ + struct user_struct *new_user; + + new_user = alloc_uid(new_ruid); + if (!new_user) + return -EAGAIN; + + if (atomic_read(&new_user->processes) >= + current->signal->rlim[RLIMIT_NPROC].rlim_cur && + new_user != &root_user) { + free_uid(new_user); + return -EAGAIN; + } + + switch_uid(new_user); + + if(dumpclear) + { + current->mm->dumpable = 0; + wmb(); + } + current->uid = new_ruid; + return 0; +} + +/* + * Unprivileged users may change the real uid to the effective uid + * or vice versa. (BSD-style) + * + * If you set the real uid at all, or set the effective uid to a value not + * equal to the real uid, then the saved uid is set to the new effective uid. + * + * This makes it possible for a setuid program to completely drop its + * privileges, which is often a useful assertion to make when you are doing + * a security audit over a program. + * + * The general idea is that a program which uses just setreuid() will be + * 100% compatible with BSD. A program which uses just setuid() will be + * 100% compatible with POSIX with saved IDs. + */ +asmlinkage long sys_setreuid(uid_t ruid, uid_t euid) +{ + int old_ruid, old_euid, old_suid, new_ruid, new_euid; + int retval; + + retval = security_task_setuid(ruid, euid, (uid_t)-1, LSM_SETID_RE); + if (retval) + return retval; + + new_ruid = old_ruid = current->uid; + new_euid = old_euid = current->euid; + old_suid = current->suid; + + if (ruid != (uid_t) -1) { + new_ruid = ruid; + if ((old_ruid != ruid) && + (current->euid != ruid) && + !capable(CAP_SETUID)) + return -EPERM; + } + + if (euid != (uid_t) -1) { + new_euid = euid; + if ((old_ruid != euid) && + (current->euid != euid) && + (current->suid != euid) && + !capable(CAP_SETUID)) + return -EPERM; + } + + if (new_ruid != old_ruid && set_user(new_ruid, new_euid != old_euid) < 0) + return -EAGAIN; + + if (new_euid != old_euid) + { + current->mm->dumpable=0; + wmb(); + } + current->fsuid = current->euid = new_euid; + if (ruid != (uid_t) -1 || + (euid != (uid_t) -1 && euid != old_ruid)) + current->suid = current->euid; + current->fsuid = current->euid; + + key_fsuid_changed(current); + + return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_RE); +} + + + +/* + * setuid() is implemented like SysV with SAVED_IDS + * + * Note that SAVED_ID's is deficient in that a setuid root program + * like sendmail, for example, cannot set its uid to be a normal + * user and then switch back, because if you're root, setuid() sets + * the saved uid too. If you don't like this, blame the bright people + * in the POSIX committee and/or USG. Note that the BSD-style setreuid() + * will allow a root program to temporarily drop privileges and be able to + * regain them by swapping the real and effective uid. + */ +asmlinkage long sys_setuid(uid_t uid) +{ + int old_euid = current->euid; + int old_ruid, old_suid, new_ruid, new_suid; + int retval; + + retval = security_task_setuid(uid, (uid_t)-1, (uid_t)-1, LSM_SETID_ID); + if (retval) + return retval; + + old_ruid = new_ruid = current->uid; + old_suid = current->suid; + new_suid = old_suid; + + if (capable(CAP_SETUID)) { + if (uid != old_ruid && set_user(uid, old_euid != uid) < 0) + return -EAGAIN; + new_suid = uid; + } else if ((uid != current->uid) && (uid != new_suid)) + return -EPERM; + + if (old_euid != uid) + { + current->mm->dumpable = 0; + wmb(); + } + current->fsuid = current->euid = uid; + current->suid = new_suid; + + key_fsuid_changed(current); + + return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_ID); +} + + +/* + * This function implements a generic ability to update ruid, euid, + * and suid. This allows you to implement the 4.4 compatible seteuid(). + */ +asmlinkage long sys_setresuid(uid_t ruid, uid_t euid, uid_t suid) +{ + int old_ruid = current->uid; + int old_euid = current->euid; + int old_suid = current->suid; + int retval; + + retval = security_task_setuid(ruid, euid, suid, LSM_SETID_RES); + if (retval) + return retval; + + if (!capable(CAP_SETUID)) { + if ((ruid != (uid_t) -1) && (ruid != current->uid) && + (ruid != current->euid) && (ruid != current->suid)) + return -EPERM; + if ((euid != (uid_t) -1) && (euid != current->uid) && + (euid != current->euid) && (euid != current->suid)) + return -EPERM; + if ((suid != (uid_t) -1) && (suid != current->uid) && + (suid != current->euid) && (suid != current->suid)) + return -EPERM; + } + if (ruid != (uid_t) -1) { + if (ruid != current->uid && set_user(ruid, euid != current->euid) < 0) + return -EAGAIN; + } + if (euid != (uid_t) -1) { + if (euid != current->euid) + { + current->mm->dumpable = 0; + wmb(); + } + current->euid = euid; + } + current->fsuid = current->euid; + if (suid != (uid_t) -1) + current->suid = suid; + + key_fsuid_changed(current); + + return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_RES); +} + +asmlinkage long sys_getresuid(uid_t __user *ruid, uid_t __user *euid, uid_t __user *suid) +{ + int retval; + + if (!(retval = put_user(current->uid, ruid)) && + !(retval = put_user(current->euid, euid))) + retval = put_user(current->suid, suid); + + return retval; +} + +/* + * Same as above, but for rgid, egid, sgid. + */ +asmlinkage long sys_setresgid(gid_t rgid, gid_t egid, gid_t sgid) +{ + int retval; + + retval = security_task_setgid(rgid, egid, sgid, LSM_SETID_RES); + if (retval) + return retval; + + if (!capable(CAP_SETGID)) { + if ((rgid != (gid_t) -1) && (rgid != current->gid) && + (rgid != current->egid) && (rgid != current->sgid)) + return -EPERM; + if ((egid != (gid_t) -1) && (egid != current->gid) && + (egid != current->egid) && (egid != current->sgid)) + return -EPERM; + if ((sgid != (gid_t) -1) && (sgid != current->gid) && + (sgid != current->egid) && (sgid != current->sgid)) + return -EPERM; + } + if (egid != (gid_t) -1) { + if (egid != current->egid) + { + current->mm->dumpable = 0; + wmb(); + } + current->egid = egid; + } + current->fsgid = current->egid; + if (rgid != (gid_t) -1) + current->gid = rgid; + if (sgid != (gid_t) -1) + current->sgid = sgid; + + key_fsgid_changed(current); + return 0; +} + +asmlinkage long sys_getresgid(gid_t __user *rgid, gid_t __user *egid, gid_t __user *sgid) +{ + int retval; + + if (!(retval = put_user(current->gid, rgid)) && + !(retval = put_user(current->egid, egid))) + retval = put_user(current->sgid, sgid); + + return retval; +} + + +/* + * "setfsuid()" sets the fsuid - the uid used for filesystem checks. This + * is used for "access()" and for the NFS daemon (letting nfsd stay at + * whatever uid it wants to). It normally shadows "euid", except when + * explicitly set by setfsuid() or for access.. + */ +asmlinkage long sys_setfsuid(uid_t uid) +{ + int old_fsuid; + + old_fsuid = current->fsuid; + if (security_task_setuid(uid, (uid_t)-1, (uid_t)-1, LSM_SETID_FS)) + return old_fsuid; + + if (uid == current->uid || uid == current->euid || + uid == current->suid || uid == current->fsuid || + capable(CAP_SETUID)) + { + if (uid != old_fsuid) + { + current->mm->dumpable = 0; + wmb(); + } + current->fsuid = uid; + } + + key_fsuid_changed(current); + + security_task_post_setuid(old_fsuid, (uid_t)-1, (uid_t)-1, LSM_SETID_FS); + + return old_fsuid; +} + +/* + * Samma på svenska.. + */ +asmlinkage long sys_setfsgid(gid_t gid) +{ + int old_fsgid; + + old_fsgid = current->fsgid; + if (security_task_setgid(gid, (gid_t)-1, (gid_t)-1, LSM_SETID_FS)) + return old_fsgid; + + if (gid == current->gid || gid == current->egid || + gid == current->sgid || gid == current->fsgid || + capable(CAP_SETGID)) + { + if (gid != old_fsgid) + { + current->mm->dumpable = 0; + wmb(); + } + current->fsgid = gid; + key_fsgid_changed(current); + } + return old_fsgid; +} + +asmlinkage long sys_times(struct tms __user * tbuf) +{ + /* + * In the SMP world we might just be unlucky and have one of + * the times increment as we use it. Since the value is an + * atomically safe type this is just fine. Conceptually its + * as if the syscall took an instant longer to occur. + */ + if (tbuf) { + struct tms tmp; + struct task_struct *tsk = current; + struct task_struct *t; + cputime_t utime, stime, cutime, cstime; + + read_lock(&tasklist_lock); + utime = tsk->signal->utime; + stime = tsk->signal->stime; + t = tsk; + do { + utime = cputime_add(utime, t->utime); + stime = cputime_add(stime, t->stime); + t = next_thread(t); + } while (t != tsk); + + /* + * While we have tasklist_lock read-locked, no dying thread + * can be updating current->signal->[us]time. Instead, + * we got their counts included in the live thread loop. + * However, another thread can come in right now and + * do a wait call that updates current->signal->c[us]time. + * To make sure we always see that pair updated atomically, + * we take the siglock around fetching them. + */ + spin_lock_irq(&tsk->sighand->siglock); + cutime = tsk->signal->cutime; + cstime = tsk->signal->cstime; + spin_unlock_irq(&tsk->sighand->siglock); + read_unlock(&tasklist_lock); + + tmp.tms_utime = cputime_to_clock_t(utime); + tmp.tms_stime = cputime_to_clock_t(stime); + tmp.tms_cutime = cputime_to_clock_t(cutime); + tmp.tms_cstime = cputime_to_clock_t(cstime); + if (copy_to_user(tbuf, &tmp, sizeof(struct tms))) + return -EFAULT; + } + return (long) jiffies_64_to_clock_t(get_jiffies_64()); +} + +/* + * This needs some heavy checking ... + * I just haven't the stomach for it. I also don't fully + * understand sessions/pgrp etc. Let somebody who does explain it. + * + * OK, I think I have the protection semantics right.... this is really + * only important on a multi-user system anyway, to make sure one user + * can't send a signal to a process owned by another. -TYT, 12/12/91 + * + * Auch. Had to add the 'did_exec' flag to conform completely to POSIX. + * LBT 04.03.94 + */ + +asmlinkage long sys_setpgid(pid_t pid, pid_t pgid) +{ + struct task_struct *p; + int err = -EINVAL; + + if (!pid) + pid = current->pid; + if (!pgid) + pgid = pid; + if (pgid < 0) + return -EINVAL; + + /* From this point forward we keep holding onto the tasklist lock + * so that our parent does not change from under us. -DaveM + */ + write_lock_irq(&tasklist_lock); + + err = -ESRCH; + p = find_task_by_pid(pid); + if (!p) + goto out; + + err = -EINVAL; + if (!thread_group_leader(p)) + goto out; + + if (p->parent == current || p->real_parent == current) { + err = -EPERM; + if (p->signal->session != current->signal->session) + goto out; + err = -EACCES; + if (p->did_exec) + goto out; + } else { + err = -ESRCH; + if (p != current) + goto out; + } + + err = -EPERM; + if (p->signal->leader) + goto out; + + if (pgid != pid) { + struct task_struct *p; + + do_each_task_pid(pgid, PIDTYPE_PGID, p) { + if (p->signal->session == current->signal->session) + goto ok_pgid; + } while_each_task_pid(pgid, PIDTYPE_PGID, p); + goto out; + } + +ok_pgid: + err = security_task_setpgid(p, pgid); + if (err) + goto out; + + if (process_group(p) != pgid) { + detach_pid(p, PIDTYPE_PGID); + p->signal->pgrp = pgid; + attach_pid(p, PIDTYPE_PGID, pgid); + } + + err = 0; +out: + /* All paths lead to here, thus we are safe. -DaveM */ + write_unlock_irq(&tasklist_lock); + return err; +} + +asmlinkage long sys_getpgid(pid_t pid) +{ + if (!pid) { + return process_group(current); + } else { + int retval; + struct task_struct *p; + + read_lock(&tasklist_lock); + p = find_task_by_pid(pid); + + retval = -ESRCH; + if (p) { + retval = security_task_getpgid(p); + if (!retval) + retval = process_group(p); + } + read_unlock(&tasklist_lock); + return retval; + } +} + +#ifdef __ARCH_WANT_SYS_GETPGRP + +asmlinkage long sys_getpgrp(void) +{ + /* SMP - assuming writes are word atomic this is fine */ + return process_group(current); +} + +#endif + +asmlinkage long sys_getsid(pid_t pid) +{ + if (!pid) { + return current->signal->session; + } else { + int retval; + struct task_struct *p; + + read_lock(&tasklist_lock); + p = find_task_by_pid(pid); + + retval = -ESRCH; + if(p) { + retval = security_task_getsid(p); + if (!retval) + retval = p->signal->session; + } + read_unlock(&tasklist_lock); + return retval; + } +} + +asmlinkage long sys_setsid(void) +{ + struct pid *pid; + int err = -EPERM; + + if (!thread_group_leader(current)) + return -EINVAL; + + down(&tty_sem); + write_lock_irq(&tasklist_lock); + + pid = find_pid(PIDTYPE_PGID, current->pid); + if (pid) + goto out; + + current->signal->leader = 1; + __set_special_pids(current->pid, current->pid); + current->signal->tty = NULL; + current->signal->tty_old_pgrp = 0; + err = process_group(current); +out: + write_unlock_irq(&tasklist_lock); + up(&tty_sem); + return err; +} + +/* + * Supplementary group IDs + */ + +/* init to 2 - one for init_task, one to ensure it is never freed */ +struct group_info init_groups = { .usage = ATOMIC_INIT(2) }; + +struct group_info *groups_alloc(int gidsetsize) +{ + struct group_info *group_info; + int nblocks; + int i; + + nblocks = (gidsetsize + NGROUPS_PER_BLOCK - 1) / NGROUPS_PER_BLOCK; + /* Make sure we always allocate at least one indirect block pointer */ + nblocks = nblocks ? : 1; + group_info = kmalloc(sizeof(*group_info) + nblocks*sizeof(gid_t *), GFP_USER); + if (!group_info) + return NULL; + group_info->ngroups = gidsetsize; + group_info->nblocks = nblocks; + atomic_set(&group_info->usage, 1); + + if (gidsetsize <= NGROUPS_SMALL) { + group_info->blocks[0] = group_info->small_block; + } else { + for (i = 0; i < nblocks; i++) { + gid_t *b; + b = (void *)__get_free_page(GFP_USER); + if (!b) + goto out_undo_partial_alloc; + group_info->blocks[i] = b; + } + } + return group_info; + +out_undo_partial_alloc: + while (--i >= 0) { + free_page((unsigned long)group_info->blocks[i]); + } + kfree(group_info); + return NULL; +} + +EXPORT_SYMBOL(groups_alloc); + +void groups_free(struct group_info *group_info) +{ + if (group_info->blocks[0] != group_info->small_block) { + int i; + for (i = 0; i < group_info->nblocks; i++) + free_page((unsigned long)group_info->blocks[i]); + } + kfree(group_info); +} + +EXPORT_SYMBOL(groups_free); + +/* export the group_info to a user-space array */ +static int groups_to_user(gid_t __user *grouplist, + struct group_info *group_info) +{ + int i; + int count = group_info->ngroups; + + for (i = 0; i < group_info->nblocks; i++) { + int cp_count = min(NGROUPS_PER_BLOCK, count); + int off = i * NGROUPS_PER_BLOCK; + int len = cp_count * sizeof(*grouplist); + + if (copy_to_user(grouplist+off, group_info->blocks[i], len)) + return -EFAULT; + + count -= cp_count; + } + return 0; +} + +/* fill a group_info from a user-space array - it must be allocated already */ +static int groups_from_user(struct group_info *group_info, + gid_t __user *grouplist) + { + int i; + int count = group_info->ngroups; + + for (i = 0; i < group_info->nblocks; i++) { + int cp_count = min(NGROUPS_PER_BLOCK, count); + int off = i * NGROUPS_PER_BLOCK; + int len = cp_count * sizeof(*grouplist); + + if (copy_from_user(group_info->blocks[i], grouplist+off, len)) + return -EFAULT; + + count -= cp_count; + } + return 0; +} + +/* a simple shell-metzner sort */ +static void groups_sort(struct group_info *group_info) +{ + int base, max, stride; + int gidsetsize = group_info->ngroups; + + for (stride = 1; stride < gidsetsize; stride = 3 * stride + 1) + ; /* nothing */ + stride /= 3; + + while (stride) { + max = gidsetsize - stride; + for (base = 0; base < max; base++) { + int left = base; + int right = left + stride; + gid_t tmp = GROUP_AT(group_info, right); + + while (left >= 0 && GROUP_AT(group_info, left) > tmp) { + GROUP_AT(group_info, right) = + GROUP_AT(group_info, left); + right = left; + left -= stride; + } + GROUP_AT(group_info, right) = tmp; + } + stride /= 3; + } +} + +/* a simple bsearch */ +static int groups_search(struct group_info *group_info, gid_t grp) +{ + int left, right; + + if (!group_info) + return 0; + + left = 0; + right = group_info->ngroups; + while (left < right) { + int mid = (left+right)/2; + int cmp = grp - GROUP_AT(group_info, mid); + if (cmp > 0) + left = mid + 1; + else if (cmp < 0) + right = mid; + else + return 1; + } + return 0; +} + +/* validate and set current->group_info */ +int set_current_groups(struct group_info *group_info) +{ + int retval; + struct group_info *old_info; + + retval = security_task_setgroups(group_info); + if (retval) + return retval; + + groups_sort(group_info); + get_group_info(group_info); + + task_lock(current); + old_info = current->group_info; + current->group_info = group_info; + task_unlock(current); + + put_group_info(old_info); + + return 0; +} + +EXPORT_SYMBOL(set_current_groups); + +asmlinkage long sys_getgroups(int gidsetsize, gid_t __user *grouplist) +{ + int i = 0; + + /* + * SMP: Nobody else can change our grouplist. Thus we are + * safe. + */ + + if (gidsetsize < 0) + return -EINVAL; + + /* no need to grab task_lock here; it cannot change */ + get_group_info(current->group_info); + i = current->group_info->ngroups; + if (gidsetsize) { + if (i > gidsetsize) { + i = -EINVAL; + goto out; + } + if (groups_to_user(grouplist, current->group_info)) { + i = -EFAULT; + goto out; + } + } +out: + put_group_info(current->group_info); + return i; +} + +/* + * SMP: Our groups are copy-on-write. We can set them safely + * without another task interfering. + */ + +asmlinkage long sys_setgroups(int gidsetsize, gid_t __user *grouplist) +{ + struct group_info *group_info; + int retval; + + if (!capable(CAP_SETGID)) + return -EPERM; + if ((unsigned)gidsetsize > NGROUPS_MAX) + return -EINVAL; + + group_info = groups_alloc(gidsetsize); + if (!group_info) + return -ENOMEM; + retval = groups_from_user(group_info, grouplist); + if (retval) { + put_group_info(group_info); + return retval; + } + + retval = set_current_groups(group_info); + put_group_info(group_info); + + return retval; +} + +/* + * Check whether we're fsgid/egid or in the supplemental group.. + */ +int in_group_p(gid_t grp) +{ + int retval = 1; + if (grp != current->fsgid) { + get_group_info(current->group_info); + retval = groups_search(current->group_info, grp); + put_group_info(current->group_info); + } + return retval; +} + +EXPORT_SYMBOL(in_group_p); + +int in_egroup_p(gid_t grp) +{ + int retval = 1; + if (grp != current->egid) { + get_group_info(current->group_info); + retval = groups_search(current->group_info, grp); + put_group_info(current->group_info); + } + return retval; +} + +EXPORT_SYMBOL(in_egroup_p); + +DECLARE_RWSEM(uts_sem); + +EXPORT_SYMBOL(uts_sem); + +asmlinkage long sys_newuname(struct new_utsname __user * name) +{ + int errno = 0; + + down_read(&uts_sem); + if (copy_to_user(name,&system_utsname,sizeof *name)) + errno = -EFAULT; + up_read(&uts_sem); + return errno; +} + +asmlinkage long sys_sethostname(char __user *name, int len) +{ + int errno; + char tmp[__NEW_UTS_LEN]; + + if (!capable(CAP_SYS_ADMIN)) + return -EPERM; + if (len < 0 || len > __NEW_UTS_LEN) + return -EINVAL; + down_write(&uts_sem); + errno = -EFAULT; + if (!copy_from_user(tmp, name, len)) { + memcpy(system_utsname.nodename, tmp, len); + system_utsname.nodename[len] = 0; + errno = 0; + } + up_write(&uts_sem); + return errno; +} + +#ifdef __ARCH_WANT_SYS_GETHOSTNAME + +asmlinkage long sys_gethostname(char __user *name, int len) +{ + int i, errno; + + if (len < 0) + return -EINVAL; + down_read(&uts_sem); + i = 1 + strlen(system_utsname.nodename); + if (i > len) + i = len; + errno = 0; + if (copy_to_user(name, system_utsname.nodename, i)) + errno = -EFAULT; + up_read(&uts_sem); + return errno; +} + +#endif + +/* + * Only setdomainname; getdomainname can be implemented by calling + * uname() + */ +asmlinkage long sys_setdomainname(char __user *name, int len) +{ + int errno; + char tmp[__NEW_UTS_LEN]; + + if (!capable(CAP_SYS_ADMIN)) + return -EPERM; + if (len < 0 || len > __NEW_UTS_LEN) + return -EINVAL; + + down_write(&uts_sem); + errno = -EFAULT; + if (!copy_from_user(tmp, name, len)) { + memcpy(system_utsname.domainname, tmp, len); + system_utsname.domainname[len] = 0; + errno = 0; + } + up_write(&uts_sem); + return errno; +} + +asmlinkage long sys_getrlimit(unsigned int resource, struct rlimit __user *rlim) +{ + if (resource >= RLIM_NLIMITS) + return -EINVAL; + else { + struct rlimit value; + task_lock(current->group_leader); + value = current->signal->rlim[resource]; + task_unlock(current->group_leader); + return copy_to_user(rlim, &value, sizeof(*rlim)) ? -EFAULT : 0; + } +} + +#ifdef __ARCH_WANT_SYS_OLD_GETRLIMIT + +/* + * Back compatibility for getrlimit. Needed for some apps. + */ + +asmlinkage long sys_old_getrlimit(unsigned int resource, struct rlimit __user *rlim) +{ + struct rlimit x; + if (resource >= RLIM_NLIMITS) + return -EINVAL; + + task_lock(current->group_leader); + x = current->signal->rlim[resource]; + task_unlock(current->group_leader); + if(x.rlim_cur > 0x7FFFFFFF) + x.rlim_cur = 0x7FFFFFFF; + if(x.rlim_max > 0x7FFFFFFF) + x.rlim_max = 0x7FFFFFFF; + return copy_to_user(rlim, &x, sizeof(x))?-EFAULT:0; +} + +#endif + +asmlinkage long sys_setrlimit(unsigned int resource, struct rlimit __user *rlim) +{ + struct rlimit new_rlim, *old_rlim; + int retval; + + if (resource >= RLIM_NLIMITS) + return -EINVAL; + if(copy_from_user(&new_rlim, rlim, sizeof(*rlim))) + return -EFAULT; + if (new_rlim.rlim_cur > new_rlim.rlim_max) + return -EINVAL; + old_rlim = current->signal->rlim + resource; + if ((new_rlim.rlim_max > old_rlim->rlim_max) && + !capable(CAP_SYS_RESOURCE)) + return -EPERM; + if (resource == RLIMIT_NOFILE && new_rlim.rlim_max > NR_OPEN) + return -EPERM; + + retval = security_task_setrlimit(resource, &new_rlim); + if (retval) + return retval; + + task_lock(current->group_leader); + *old_rlim = new_rlim; + task_unlock(current->group_leader); + + if (resource == RLIMIT_CPU && new_rlim.rlim_cur != RLIM_INFINITY && + (cputime_eq(current->signal->it_prof_expires, cputime_zero) || + new_rlim.rlim_cur <= cputime_to_secs( + current->signal->it_prof_expires))) { + cputime_t cputime = secs_to_cputime(new_rlim.rlim_cur); + read_lock(&tasklist_lock); + spin_lock_irq(¤t->sighand->siglock); + set_process_cpu_timer(current, CPUCLOCK_PROF, + &cputime, NULL); + spin_unlock_irq(¤t->sighand->siglock); + read_unlock(&tasklist_lock); + } + + return 0; +} + +/* + * It would make sense to put struct rusage in the task_struct, + * except that would make the task_struct be *really big*. After + * task_struct gets moved into malloc'ed memory, it would + * make sense to do this. It will make moving the rest of the information + * a lot simpler! (Which we're not doing right now because we're not + * measuring them yet). + * + * This expects to be called with tasklist_lock read-locked or better, + * and the siglock not locked. It may momentarily take the siglock. + * + * When sampling multiple threads for RUSAGE_SELF, under SMP we might have + * races with threads incrementing their own counters. But since word + * reads are atomic, we either get new values or old values and we don't + * care which for the sums. We always take the siglock to protect reading + * the c* fields from p->signal from races with exit.c updating those + * fields when reaping, so a sample either gets all the additions of a + * given child after it's reaped, or none so this sample is before reaping. + */ + +static void k_getrusage(struct task_struct *p, int who, struct rusage *r) +{ + struct task_struct *t; + unsigned long flags; + cputime_t utime, stime; + + memset((char *) r, 0, sizeof *r); + + if (unlikely(!p->signal)) + return; + + switch (who) { + case RUSAGE_CHILDREN: + spin_lock_irqsave(&p->sighand->siglock, flags); + utime = p->signal->cutime; + stime = p->signal->cstime; + r->ru_nvcsw = p->signal->cnvcsw; + r->ru_nivcsw = p->signal->cnivcsw; + r->ru_minflt = p->signal->cmin_flt; + r->ru_majflt = p->signal->cmaj_flt; + spin_unlock_irqrestore(&p->sighand->siglock, flags); + cputime_to_timeval(utime, &r->ru_utime); + cputime_to_timeval(stime, &r->ru_stime); + break; + case RUSAGE_SELF: + spin_lock_irqsave(&p->sighand->siglock, flags); + utime = stime = cputime_zero; + goto sum_group; + case RUSAGE_BOTH: + spin_lock_irqsave(&p->sighand->siglock, flags); + utime = p->signal->cutime; + stime = p->signal->cstime; + r->ru_nvcsw = p->signal->cnvcsw; + r->ru_nivcsw = p->signal->cnivcsw; + r->ru_minflt = p->signal->cmin_flt; + r->ru_majflt = p->signal->cmaj_flt; + sum_group: + utime = cputime_add(utime, p->signal->utime); + stime = cputime_add(stime, p->signal->stime); + r->ru_nvcsw += p->signal->nvcsw; + r->ru_nivcsw += p->signal->nivcsw; + r->ru_minflt += p->signal->min_flt; + r->ru_majflt += p->signal->maj_flt; + t = p; + do { + utime = cputime_add(utime, t->utime); + stime = cputime_add(stime, t->stime); + r->ru_nvcsw += t->nvcsw; + r->ru_nivcsw += t->nivcsw; + r->ru_minflt += t->min_flt; + r->ru_majflt += t->maj_flt; + t = next_thread(t); + } while (t != p); + spin_unlock_irqrestore(&p->sighand->siglock, flags); + cputime_to_timeval(utime, &r->ru_utime); + cputime_to_timeval(stime, &r->ru_stime); + break; + default: + BUG(); + } +} + +int getrusage(struct task_struct *p, int who, struct rusage __user *ru) +{ + struct rusage r; + read_lock(&tasklist_lock); + k_getrusage(p, who, &r); + read_unlock(&tasklist_lock); + return copy_to_user(ru, &r, sizeof(r)) ? -EFAULT : 0; +} + +asmlinkage long sys_getrusage(int who, struct rusage __user *ru) +{ + if (who != RUSAGE_SELF && who != RUSAGE_CHILDREN) + return -EINVAL; + return getrusage(current, who, ru); +} + +asmlinkage long sys_umask(int mask) +{ + mask = xchg(¤t->fs->umask, mask & S_IRWXUGO); + return mask; +} + +asmlinkage long sys_prctl(int option, unsigned long arg2, unsigned long arg3, + unsigned long arg4, unsigned long arg5) +{ + long error; + int sig; + + error = security_task_prctl(option, arg2, arg3, arg4, arg5); + if (error) + return error; + + switch (option) { + case PR_SET_PDEATHSIG: + sig = arg2; + if (sig < 0 || sig > _NSIG) { + error = -EINVAL; + break; + } + current->pdeath_signal = sig; + break; + case PR_GET_PDEATHSIG: + error = put_user(current->pdeath_signal, (int __user *)arg2); + break; + case PR_GET_DUMPABLE: + if (current->mm->dumpable) + error = 1; + break; + case PR_SET_DUMPABLE: + if (arg2 != 0 && arg2 != 1) { + error = -EINVAL; + break; + } + current->mm->dumpable = arg2; + break; + + case PR_SET_UNALIGN: + error = SET_UNALIGN_CTL(current, arg2); + break; + case PR_GET_UNALIGN: + error = GET_UNALIGN_CTL(current, arg2); + break; + case PR_SET_FPEMU: + error = SET_FPEMU_CTL(current, arg2); + break; + case PR_GET_FPEMU: + error = GET_FPEMU_CTL(current, arg2); + break; + case PR_SET_FPEXC: + error = SET_FPEXC_CTL(current, arg2); + break; + case PR_GET_FPEXC: + error = GET_FPEXC_CTL(current, arg2); + break; + case PR_GET_TIMING: + error = PR_TIMING_STATISTICAL; + break; + case PR_SET_TIMING: + if (arg2 == PR_TIMING_STATISTICAL) + error = 0; + else + error = -EINVAL; + break; + + case PR_GET_KEEPCAPS: + if (current->keep_capabilities) + error = 1; + break; + case PR_SET_KEEPCAPS: + if (arg2 != 0 && arg2 != 1) { + error = -EINVAL; + break; + } + current->keep_capabilities = arg2; + break; + case PR_SET_NAME: { + struct task_struct *me = current; + unsigned char ncomm[sizeof(me->comm)]; + + ncomm[sizeof(me->comm)-1] = 0; + if (strncpy_from_user(ncomm, (char __user *)arg2, + sizeof(me->comm)-1) < 0) + return -EFAULT; + set_task_comm(me, ncomm); + return 0; + } + case PR_GET_NAME: { + struct task_struct *me = current; + unsigned char tcomm[sizeof(me->comm)]; + + get_task_comm(tcomm, me); + if (copy_to_user((char __user *)arg2, tcomm, sizeof(tcomm))) + return -EFAULT; + return 0; + } + default: + error = -EINVAL; + break; + } + return error; +} |
