| /* |
| * linux/kernel/exit.c |
| * |
| * Copyright (C) 1991, 1992 Linus Torvalds |
| */ |
| |
| #include <linux/config.h> |
| #include <linux/slab.h> |
| #include <linux/interrupt.h> |
| #include <linux/smp_lock.h> |
| #include <linux/module.h> |
| #include <linux/completion.h> |
| #include <linux/personality.h> |
| #include <linux/tty.h> |
| #include <linux/namespace.h> |
| #ifdef CONFIG_BSD_PROCESS_ACCT |
| #include <linux/acct.h> |
| #endif |
| |
| #include <asm/uaccess.h> |
| #include <asm/pgtable.h> |
| #include <asm/mmu_context.h> |
| |
| extern void sem_exit (void); |
| extern struct task_struct *child_reaper; |
| |
| int getrusage(struct task_struct *, int, struct rusage *); |
| |
| static void release_task(struct task_struct * p) |
| { |
| if (p != current) { |
| #ifdef CONFIG_SMP |
| /* |
| * Wait to make sure the process isn't on the |
| * runqueue (active on some other CPU still) |
| */ |
| for (;;) { |
| task_lock(p); |
| if (!task_has_cpu(p)) |
| break; |
| task_unlock(p); |
| do { |
| cpu_relax(); |
| barrier(); |
| } while (task_has_cpu(p)); |
| } |
| task_unlock(p); |
| #endif |
| atomic_dec(&p->user->processes); |
| free_uid(p->user); |
| unhash_process(p); |
| |
| release_thread(p); |
| current->cmin_flt += p->min_flt + p->cmin_flt; |
| current->cmaj_flt += p->maj_flt + p->cmaj_flt; |
| current->cnswap += p->nswap + p->cnswap; |
| /* |
| * Potentially available timeslices are retrieved |
| * here - this way the parent does not get penalized |
| * for creating too many processes. |
| * |
| * (this cannot be used to artificially 'generate' |
| * timeslices, because any timeslice recovered here |
| * was given away by the parent in the first place.) |
| */ |
| current->counter += p->counter; |
| if (current->counter >= MAX_COUNTER) |
| current->counter = MAX_COUNTER; |
| p->pid = 0; |
| free_task_struct(p); |
| } else { |
| printk("task releasing itself\n"); |
| } |
| } |
| |
| /* |
| * This checks not only the pgrp, but falls back on the pid if no |
| * satisfactory pgrp is found. I dunno - gdb doesn't work correctly |
| * without this... |
| */ |
| int session_of_pgrp(int pgrp) |
| { |
| struct task_struct *p; |
| int fallback; |
| |
| fallback = -1; |
| read_lock(&tasklist_lock); |
| for_each_task(p) { |
| if (p->session <= 0) |
| continue; |
| if (p->pgrp == pgrp) { |
| fallback = p->session; |
| break; |
| } |
| if (p->pid == pgrp) |
| fallback = p->session; |
| } |
| read_unlock(&tasklist_lock); |
| return fallback; |
| } |
| |
| /* |
| * Determine if a process group is "orphaned", according to the POSIX |
| * definition in 2.2.2.52. Orphaned process groups are not to be affected |
| * by terminal-generated stop signals. Newly orphaned process groups are |
| * to receive a SIGHUP and a SIGCONT. |
| * |
| * "I ask you, have you ever known what it is to be an orphan?" |
| */ |
| static int will_become_orphaned_pgrp(int pgrp, struct task_struct * ignored_task) |
| { |
| struct task_struct *p; |
| |
| read_lock(&tasklist_lock); |
| for_each_task(p) { |
| if ((p == ignored_task) || (p->pgrp != pgrp) || |
| (p->state == TASK_ZOMBIE) || |
| (p->p_pptr->pid == 1)) |
| continue; |
| if ((p->p_pptr->pgrp != pgrp) && |
| (p->p_pptr->session == p->session)) { |
| read_unlock(&tasklist_lock); |
| return 0; |
| } |
| } |
| read_unlock(&tasklist_lock); |
| return 1; /* (sighing) "Often!" */ |
| } |
| |
| int is_orphaned_pgrp(int pgrp) |
| { |
| return will_become_orphaned_pgrp(pgrp, 0); |
| } |
| |
| static inline int has_stopped_jobs(int pgrp) |
| { |
| int retval = 0; |
| struct task_struct * p; |
| |
| read_lock(&tasklist_lock); |
| for_each_task(p) { |
| if (p->pgrp != pgrp) |
| continue; |
| if (p->state != TASK_STOPPED) |
| continue; |
| retval = 1; |
| break; |
| } |
| read_unlock(&tasklist_lock); |
| return retval; |
| } |
| |
| /* |
| * When we die, we re-parent all our children. |
| * Try to give them to another thread in our thread |
| * group, and if no such member exists, give it to |
| * the global child reaper process (ie "init") |
| */ |
| static inline void forget_original_parent(struct task_struct * father) |
| { |
| struct task_struct * p; |
| |
| read_lock(&tasklist_lock); |
| |
| for_each_task(p) { |
| if (p->p_opptr == father) { |
| /* We dont want people slaying init */ |
| p->exit_signal = SIGCHLD; |
| p->self_exec_id++; |
| |
| /* Make sure we're not reparenting to ourselves */ |
| p->p_opptr = child_reaper; |
| |
| if (p->pdeath_signal) send_sig(p->pdeath_signal, p, 0); |
| } |
| } |
| read_unlock(&tasklist_lock); |
| } |
| |
| static inline void close_files(struct files_struct * files) |
| { |
| int i, j; |
| |
| j = 0; |
| for (;;) { |
| unsigned long set; |
| i = j * __NFDBITS; |
| if (i >= files->max_fdset || i >= files->max_fds) |
| break; |
| set = files->open_fds->fds_bits[j++]; |
| while (set) { |
| if (set & 1) { |
| struct file * file = xchg(&files->fd[i], NULL); |
| if (file) |
| filp_close(file, files); |
| } |
| i++; |
| set >>= 1; |
| } |
| } |
| } |
| |
| void put_files_struct(struct files_struct *files) |
| { |
| if (atomic_dec_and_test(&files->count)) { |
| close_files(files); |
| /* |
| * Free the fd and fdset arrays if we expanded them. |
| */ |
| if (files->fd != &files->fd_array[0]) |
| free_fd_array(files->fd, files->max_fds); |
| if (files->max_fdset > __FD_SETSIZE) { |
| free_fdset(files->open_fds, files->max_fdset); |
| free_fdset(files->close_on_exec, files->max_fdset); |
| } |
| kmem_cache_free(files_cachep, files); |
| } |
| } |
| |
| static inline void __exit_files(struct task_struct *tsk) |
| { |
| struct files_struct * files = tsk->files; |
| |
| if (files) { |
| task_lock(tsk); |
| tsk->files = NULL; |
| task_unlock(tsk); |
| put_files_struct(files); |
| } |
| } |
| |
| void exit_files(struct task_struct *tsk) |
| { |
| __exit_files(tsk); |
| } |
| |
| static inline void __put_fs_struct(struct fs_struct *fs) |
| { |
| /* No need to hold fs->lock if we are killing it */ |
| if (atomic_dec_and_test(&fs->count)) { |
| dput(fs->root); |
| mntput(fs->rootmnt); |
| dput(fs->pwd); |
| mntput(fs->pwdmnt); |
| if (fs->altroot) { |
| dput(fs->altroot); |
| mntput(fs->altrootmnt); |
| } |
| kmem_cache_free(fs_cachep, fs); |
| } |
| } |
| |
| void put_fs_struct(struct fs_struct *fs) |
| { |
| __put_fs_struct(fs); |
| } |
| |
| static inline void __exit_fs(struct task_struct *tsk) |
| { |
| struct fs_struct * fs = tsk->fs; |
| |
| if (fs) { |
| task_lock(tsk); |
| tsk->fs = NULL; |
| task_unlock(tsk); |
| __put_fs_struct(fs); |
| } |
| } |
| |
| void exit_fs(struct task_struct *tsk) |
| { |
| __exit_fs(tsk); |
| } |
| |
| /* |
| * We can use these to temporarily drop into |
| * "lazy TLB" mode and back. |
| */ |
| struct mm_struct * start_lazy_tlb(void) |
| { |
| struct mm_struct *mm = current->mm; |
| current->mm = NULL; |
| /* active_mm is still 'mm' */ |
| atomic_inc(&mm->mm_count); |
| enter_lazy_tlb(mm, current, smp_processor_id()); |
| return mm; |
| } |
| |
| void end_lazy_tlb(struct mm_struct *mm) |
| { |
| struct mm_struct *active_mm = current->active_mm; |
| |
| current->mm = mm; |
| if (mm != active_mm) { |
| current->active_mm = mm; |
| activate_mm(active_mm, mm); |
| } |
| mmdrop(active_mm); |
| } |
| |
| /* |
| * Turn us into a lazy TLB process if we |
| * aren't already.. |
| */ |
| static inline void __exit_mm(struct task_struct * tsk) |
| { |
| struct mm_struct * mm = tsk->mm; |
| |
| mm_release(); |
| if (mm) { |
| atomic_inc(&mm->mm_count); |
| BUG_ON(mm != tsk->active_mm); |
| /* more a memory barrier than a real lock */ |
| task_lock(tsk); |
| tsk->mm = NULL; |
| task_unlock(tsk); |
| enter_lazy_tlb(mm, current, smp_processor_id()); |
| mmput(mm); |
| } |
| } |
| |
| void exit_mm(struct task_struct *tsk) |
| { |
| __exit_mm(tsk); |
| } |
| |
| /* |
| * Send signals to all our closest relatives so that they know |
| * to properly mourn us.. |
| */ |
| static void exit_notify(void) |
| { |
| struct task_struct * p, *t; |
| |
| forget_original_parent(current); |
| /* |
| * Check to see if any process groups have become orphaned |
| * as a result of our exiting, and if they have any stopped |
| * jobs, send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2) |
| * |
| * Case i: Our father is in a different pgrp than we are |
| * and we were the only connection outside, so our pgrp |
| * is about to become orphaned. |
| */ |
| |
| t = current->p_pptr; |
| |
| if ((t->pgrp != current->pgrp) && |
| (t->session == current->session) && |
| will_become_orphaned_pgrp(current->pgrp, current) && |
| has_stopped_jobs(current->pgrp)) { |
| kill_pg(current->pgrp,SIGHUP,1); |
| kill_pg(current->pgrp,SIGCONT,1); |
| } |
| |
| /* Let father know we died |
| * |
| * Thread signals are configurable, but you aren't going to use |
| * that to send signals to arbitary processes. |
| * That stops right now. |
| * |
| * If the parent exec id doesn't match the exec id we saved |
| * when we started then we know the parent has changed security |
| * domain. |
| * |
| * If our self_exec id doesn't match our parent_exec_id then |
| * we have changed execution domain as these two values started |
| * the same after a fork. |
| * |
| */ |
| |
| if (current->exit_signal && current->exit_signal != SIGCHLD && |
| ( current->parent_exec_id != t->self_exec_id || |
| current->self_exec_id != current->parent_exec_id)) |
| current->exit_signal = SIGCHLD; |
| |
| |
| /* |
| * This loop does two things: |
| * |
| * A. Make init inherit all the child processes |
| * B. Check to see if any process groups have become orphaned |
| * as a result of our exiting, and if they have any stopped |
| * jobs, send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2) |
| */ |
| |
| write_lock_irq(&tasklist_lock); |
| current->state = TASK_ZOMBIE; |
| do_notify_parent(current, current->exit_signal); |
| while (current->p_cptr != NULL) { |
| p = current->p_cptr; |
| current->p_cptr = p->p_osptr; |
| p->p_ysptr = NULL; |
| p->ptrace = 0; |
| |
| p->p_pptr = p->p_opptr; |
| p->p_osptr = p->p_pptr->p_cptr; |
| if (p->p_osptr) |
| p->p_osptr->p_ysptr = p; |
| p->p_pptr->p_cptr = p; |
| if (p->state == TASK_ZOMBIE) |
| do_notify_parent(p, p->exit_signal); |
| /* |
| * process group orphan check |
| * Case ii: Our child is in a different pgrp |
| * than we are, and it was the only connection |
| * outside, so the child pgrp is now orphaned. |
| */ |
| if ((p->pgrp != current->pgrp) && |
| (p->session == current->session)) { |
| int pgrp = p->pgrp; |
| |
| write_unlock_irq(&tasklist_lock); |
| if (is_orphaned_pgrp(pgrp) && has_stopped_jobs(pgrp)) { |
| kill_pg(pgrp,SIGHUP,1); |
| kill_pg(pgrp,SIGCONT,1); |
| } |
| write_lock_irq(&tasklist_lock); |
| } |
| } |
| write_unlock_irq(&tasklist_lock); |
| } |
| |
| NORET_TYPE void do_exit(long code) |
| { |
| struct task_struct *tsk = current; |
| |
| if (in_interrupt()) |
| panic("Aiee, killing interrupt handler!"); |
| if (!tsk->pid) |
| panic("Attempted to kill the idle task!"); |
| if (tsk->pid == 1) |
| panic("Attempted to kill init!"); |
| tsk->flags |= PF_EXITING; |
| del_timer_sync(&tsk->real_timer); |
| |
| fake_volatile: |
| #ifdef CONFIG_BSD_PROCESS_ACCT |
| acct_process(code); |
| #endif |
| __exit_mm(tsk); |
| |
| lock_kernel(); |
| sem_exit(); |
| __exit_files(tsk); |
| __exit_fs(tsk); |
| exit_namespace(tsk); |
| exit_sighand(tsk); |
| exit_thread(); |
| |
| if (current->leader) |
| disassociate_ctty(1); |
| |
| put_exec_domain(tsk->exec_domain); |
| if (tsk->binfmt && tsk->binfmt->module) |
| __MOD_DEC_USE_COUNT(tsk->binfmt->module); |
| |
| tsk->exit_code = code; |
| exit_notify(); |
| schedule(); |
| BUG(); |
| /* |
| * In order to get rid of the "volatile function does return" message |
| * I did this little loop that confuses gcc to think do_exit really |
| * is volatile. In fact it's schedule() that is volatile in some |
| * circumstances: when current->state = ZOMBIE, schedule() never |
| * returns. |
| * |
| * In fact the natural way to do all this is to have the label and the |
| * goto right after each other, but I put the fake_volatile label at |
| * the start of the function just in case something /really/ bad |
| * happens, and the schedule returns. This way we can try again. I'm |
| * not paranoid: it's just that everybody is out to get me. |
| */ |
| goto fake_volatile; |
| } |
| |
| NORET_TYPE void complete_and_exit(struct completion *comp, long code) |
| { |
| if (comp) |
| complete(comp); |
| |
| do_exit(code); |
| } |
| |
| asmlinkage long sys_exit(int error_code) |
| { |
| do_exit((error_code&0xff)<<8); |
| } |
| |
| asmlinkage long sys_wait4(pid_t pid,unsigned int * stat_addr, int options, struct rusage * ru) |
| { |
| int flag, retval; |
| DECLARE_WAITQUEUE(wait, current); |
| struct task_struct *tsk; |
| |
| if (options & ~(WNOHANG|WUNTRACED|__WNOTHREAD|__WCLONE|__WALL)) |
| return -EINVAL; |
| |
| add_wait_queue(¤t->wait_chldexit,&wait); |
| repeat: |
| flag = 0; |
| current->state = TASK_INTERRUPTIBLE; |
| read_lock(&tasklist_lock); |
| tsk = current; |
| do { |
| struct task_struct *p; |
| for (p = tsk->p_cptr ; p ; p = p->p_osptr) { |
| if (pid>0) { |
| if (p->pid != pid) |
| continue; |
| } else if (!pid) { |
| if (p->pgrp != current->pgrp) |
| continue; |
| } else if (pid != -1) { |
| if (p->pgrp != -pid) |
| continue; |
| } |
| /* Wait for all children (clone and not) if __WALL is set; |
| * otherwise, wait for clone children *only* if __WCLONE is |
| * set; otherwise, wait for non-clone children *only*. (Note: |
| * A "clone" child here is one that reports to its parent |
| * using a signal other than SIGCHLD.) */ |
| if (((p->exit_signal != SIGCHLD) ^ ((options & __WCLONE) != 0)) |
| && !(options & __WALL)) |
| continue; |
| flag = 1; |
| switch (p->state) { |
| case TASK_STOPPED: |
| if (!p->exit_code) |
| continue; |
| if (!(options & WUNTRACED) && !(p->ptrace & PT_PTRACED)) |
| continue; |
| read_unlock(&tasklist_lock); |
| retval = ru ? getrusage(p, RUSAGE_BOTH, ru) : 0; |
| if (!retval && stat_addr) |
| retval = put_user((p->exit_code << 8) | 0x7f, stat_addr); |
| if (!retval) { |
| p->exit_code = 0; |
| retval = p->pid; |
| } |
| goto end_wait4; |
| case TASK_ZOMBIE: |
| current->times.tms_cutime += p->times.tms_utime + p->times.tms_cutime; |
| current->times.tms_cstime += p->times.tms_stime + p->times.tms_cstime; |
| read_unlock(&tasklist_lock); |
| retval = ru ? getrusage(p, RUSAGE_BOTH, ru) : 0; |
| if (!retval && stat_addr) |
| retval = put_user(p->exit_code, stat_addr); |
| if (retval) |
| goto end_wait4; |
| retval = p->pid; |
| if (p->p_opptr != p->p_pptr) { |
| write_lock_irq(&tasklist_lock); |
| REMOVE_LINKS(p); |
| p->p_pptr = p->p_opptr; |
| SET_LINKS(p); |
| do_notify_parent(p, SIGCHLD); |
| write_unlock_irq(&tasklist_lock); |
| } else |
| release_task(p); |
| goto end_wait4; |
| default: |
| continue; |
| } |
| } |
| if (options & __WNOTHREAD) |
| break; |
| tsk = next_thread(tsk); |
| } while (tsk != current); |
| read_unlock(&tasklist_lock); |
| if (flag) { |
| retval = 0; |
| if (options & WNOHANG) |
| goto end_wait4; |
| retval = -ERESTARTSYS; |
| if (signal_pending(current)) |
| goto end_wait4; |
| schedule(); |
| goto repeat; |
| } |
| retval = -ECHILD; |
| end_wait4: |
| current->state = TASK_RUNNING; |
| remove_wait_queue(¤t->wait_chldexit,&wait); |
| return retval; |
| } |
| |
| #if !defined(__alpha__) && !defined(__ia64__) |
| |
| /* |
| * sys_waitpid() remains for compatibility. waitpid() should be |
| * implemented by calling sys_wait4() from libc.a. |
| */ |
| asmlinkage long sys_waitpid(pid_t pid,unsigned int * stat_addr, int options) |
| { |
| return sys_wait4(pid, stat_addr, options, NULL); |
| } |
| |
| #endif |