Loading...
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 | /*
* linux/kernel/exit.c
*
* (C) 1991 Linus Torvalds
*/
#define DEBUG_PROC_TREE
#include <errno.h>
#include <signal.h>
#include <sys/wait.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/tty.h>
#include <asm/segment.h>
int sys_close(int fd);
int send_sig(long sig,struct task_struct * p,int priv)
{
if (!p || (sig < 0) || (sig > 32))
return -EINVAL;
if (!priv && ((sig != SIGCONT) || (current->session != p->session)) &&
(current->euid != p->euid) && !suser())
return -EPERM;
if (!sig)
return 0;
if ((sig == SIGKILL) || (sig == SIGCONT)) {
if (p->state == TASK_STOPPED)
p->state = TASK_RUNNING;
p->exit_code = 0;
p->signal &= ~( (1<<(SIGSTOP-1)) | (1<<(SIGTSTP-1)) |
(1<<(SIGTTIN-1)) | (1<<(SIGTTOU-1)) );
}
/* Depends on order SIGSTOP, SIGTSTP, SIGTTIN, SIGTTOU */
if ((sig >= SIGSTOP) && (sig <= SIGTTOU))
p->signal &= ~(1<<(SIGCONT-1));
/* Actually deliver the signal */
p->signal |= (1<<(sig-1));
if (p->flags & PF_PTRACED) {
/* save the signal number for wait. */
p->exit_code = sig;
/* we have to make sure the parent is awake. */
if (p->p_pptr != NULL && p->p_pptr->state == TASK_INTERRUPTIBLE)
p->p_pptr->state = TASK_RUNNING;
/* we have to make sure that the process stops. */
if (p->state == TASK_INTERRUPTIBLE || p->state == TASK_RUNNING)
p->state = TASK_STOPPED;
}
return 0;
}
void release(struct task_struct * p)
{
int i;
if (!p)
return;
if (p == current) {
printk("task releasing itself\n\r");
return;
}
for (i=1 ; i<NR_TASKS ; i++)
if (task[i] == p) {
task[i] = NULL;
/* Update links */
if (p->p_osptr)
p->p_osptr->p_ysptr = p->p_ysptr;
if (p->p_ysptr)
p->p_ysptr->p_osptr = p->p_osptr;
else
p->p_pptr->p_cptr = p->p_osptr;
free_page((long) p);
return;
}
panic("trying to release non-existent task");
}
#ifdef DEBUG_PROC_TREE
/*
* Check to see if a task_struct pointer is present in the task[] array
* Return 0 if found, and 1 if not found.
*/
int bad_task_ptr(struct task_struct *p)
{
int i;
if (!p)
return 0;
for (i=0 ; i<NR_TASKS ; i++)
if (task[i] == p)
return 0;
return 1;
}
/*
* This routine scans the pid tree and make sure the rep invarient still
* holds. Used for debugging only, since it's very slow....
*
* It looks a lot scarier than it really is.... we're doing ænothing more
* than verifying the doubly-linked list foundæin p_ysptr and p_osptr,
* and checking it corresponds with the process tree defined by p_cptr and
* p_pptr;
*/
void audit_ptree()
{
int i;
for (i=1 ; i<NR_TASKS ; i++) {
if (!task[i])
continue;
if (bad_task_ptr(task[i]->p_pptr))
printk("Warning, pid %d's parent link is bad\n",
task[i]->pid);
if (bad_task_ptr(task[i]->p_cptr))
printk("Warning, pid %d's child link is bad\n",
task[i]->pid);
if (bad_task_ptr(task[i]->p_ysptr))
printk("Warning, pid %d's ys link is bad\n",
task[i]->pid);
if (bad_task_ptr(task[i]->p_osptr))
printk("Warning, pid %d's os link is bad\n",
task[i]->pid);
if (task[i]->p_pptr == task[i])
printk("Warning, pid %d parent link points to self\n");
if (task[i]->p_cptr == task[i])
printk("Warning, pid %d child link points to self\n");
if (task[i]->p_ysptr == task[i])
printk("Warning, pid %d ys link points to self\n");
if (task[i]->p_osptr == task[i])
printk("Warning, pid %d os link points to self\n");
if (task[i]->p_osptr) {
if (task[i]->p_pptr != task[i]->p_osptr->p_pptr)
printk(
"Warning, pid %d older sibling %d parent is %d\n",
task[i]->pid, task[i]->p_osptr->pid,
task[i]->p_osptr->p_pptr->pid);
if (task[i]->p_osptr->p_ysptr != task[i])
printk(
"Warning, pid %d older sibling %d has mismatched ys link\n",
task[i]->pid, task[i]->p_osptr->pid);
}
if (task[i]->p_ysptr) {
if (task[i]->p_pptr != task[i]->p_ysptr->p_pptr)
printk(
"Warning, pid %d younger sibling %d parent is %d\n",
task[i]->pid, task[i]->p_osptr->pid,
task[i]->p_osptr->p_pptr->pid);
if (task[i]->p_ysptr->p_osptr != task[i])
printk(
"Warning, pid %d younger sibling %d has mismatched os link\n",
task[i]->pid, task[i]->p_ysptr->pid);
}
if (task[i]->p_cptr) {
if (task[i]->p_cptr->p_pptr != task[i])
printk(
"Warning, pid %d youngest child %d has mismatched parent link\n",
task[i]->pid, task[i]->p_cptr->pid);
if (task[i]->p_cptr->p_ysptr)
printk(
"Warning, pid %d youngest child %d has non-NULL ys link\n",
task[i]->pid, task[i]->p_cptr->pid);
}
}
}
#endif /* DEBUG_PROC_TREE */
/*
* This checks not only the pgrp, but falls back on the pid if no
* satisfactory prgp 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;
for (p = &LAST_TASK ; p > &FIRST_TASK ; --p) {
if (!*p || (*p)->session <= 0)
continue;
if ((*p)->pgrp == pgrp)
return (*p)->session;
if ((*p)->pid == pgrp)
fallback = (*p)->session;
}
return fallback;
}
int kill_pg(int pgrp, int sig, int priv)
{
struct task_struct **p;
int err,retval = -ESRCH;
int found = 0;
if (sig<0 || sig>32 || pgrp<=0)
return -EINVAL;
for (p = &LAST_TASK ; p > &FIRST_TASK ; --p)
if (*p && (*p)->pgrp == pgrp) {
if (sig && (err = send_sig(sig,*p,priv)))
retval = err;
else
found++;
}
return(found ? 0 : retval);
}
int kill_proc(int pid, int sig, int priv)
{
struct task_struct **p;
if (sig<0 || sig>32)
return -EINVAL;
for (p = &LAST_TASK ; p > &FIRST_TASK ; --p)
if (*p && (*p)->pid == pid)
return(sig ? send_sig(sig,*p,priv) : 0);
return(-ESRCH);
}
/*
* POSIX specifies that kill(-1,sig) is unspecified, but what we have
* is probably wrong. Should make it like BSD or SYSV.
*/
int sys_kill(int pid,int sig)
{
struct task_struct **p = NR_TASKS + task;
int err, retval = 0, count = 0;
if (!pid)
return(kill_pg(current->pgrp,sig,0));
if (pid == -1) {
while (--p > &FIRST_TASK)
if (*p && (*p)->pid > 1 && *p != current) {
++count;
if ((err = send_sig(sig,*p,0)) != -EPERM)
retval = err;
}
return(count ? retval : -ESRCH);
}
if (pid < 0)
return(kill_pg(-pid,sig,0));
/* Normal kill */
return(kill_proc(pid,sig,0));
}
/*
* 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?"
*/
int is_orphaned_pgrp(int pgrp)
{
struct task_struct **p;
for (p = &LAST_TASK ; p > &FIRST_TASK ; --p) {
if (!(*p) ||
((*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))
return 0;
}
return(1); /* (sighing) "Often!" */
}
static int has_stopped_jobs(int pgrp)
{
struct task_struct ** p;
for (p = &LAST_TASK ; p > &FIRST_TASK ; --p) {
if (!*p || (*p)->pgrp != pgrp)
continue;
if ((*p)->state == TASK_STOPPED)
return(1);
}
return(0);
}
volatile void do_exit(long code)
{
struct task_struct *p;
int i;
free_page_tables(get_base(current->ldt[1]),get_limit(0x0f));
free_page_tables(get_base(current->ldt[2]),get_limit(0x17));
for (i=0 ; i<NR_OPEN ; i++)
if (current->filp[i])
sys_close(i);
iput(current->pwd);
current->pwd = NULL;
iput(current->root);
current->root = NULL;
iput(current->executable);
current->executable = NULL;
for (i=0; i < current->numlibraries; i++) {
iput(current->libraries[i].library);
current->libraries[i].library = NULL;
}
current->state = TASK_ZOMBIE;
current->exit_code = code;
current->rss = 0;
/*
* 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 SIGUP 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.
*/
if ((current->p_pptr->pgrp != current->pgrp) &&
(current->p_pptr->session == current->session) &&
is_orphaned_pgrp(current->pgrp) &&
has_stopped_jobs(current->pgrp)) {
kill_pg(current->pgrp,SIGHUP,1);
kill_pg(current->pgrp,SIGCONT,1);
}
/* Let father know we died */
send_sig (SIGCHLD, current->p_pptr, 1);
/*
* 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
* jons, send them a SIGUP and then a SIGCONT. (POSIX 3.2.2.2)
*/
while (p = current->p_cptr) {
current->p_cptr = p->p_osptr;
p->p_ysptr = NULL;
p->flags &= ~PF_PTRACED;
p->p_pptr = task[1];
p->p_osptr = task[1]->p_cptr;
task[1]->p_cptr->p_ysptr = p;
task[1]->p_cptr = p;
if (p->state == TASK_ZOMBIE)
task[1]->signal |= (1<<(SIGCHLD-1));
/*
* 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) &&
is_orphaned_pgrp(p->pgrp) &&
has_stopped_jobs(p->pgrp)) {
kill_pg(p->pgrp,SIGHUP,1);
kill_pg(p->pgrp,SIGCONT,1);
}
}
if (current->leader) {
struct task_struct **p;
struct tty_struct *tty;
if (current->tty >= 0) {
tty = TTY_TABLE(current->tty);
if (tty->pgrp > 0)
kill_pg(tty->pgrp, SIGHUP, 1);
tty->pgrp = -1;
tty->session = 0;
}
for (p = &LAST_TASK ; p > &FIRST_TASK ; --p)
if (*p && (*p)->session == current->session)
(*p)->tty = -1;
}
if (last_task_used_math == current)
last_task_used_math = NULL;
#ifdef DEBUG_PROC_TREE
audit_ptree();
#endif
schedule();
}
int sys_exit(int error_code)
{
do_exit((error_code&0xff)<<8);
}
int sys_waitpid(pid_t pid,unsigned long * stat_addr, int options)
{
int flag;
struct task_struct *p;
unsigned long oldblocked;
if (stat_addr)
verify_area(stat_addr,4);
repeat:
flag=0;
for (p = current->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;
}
switch (p->state) {
case TASK_STOPPED:
if (!p->exit_code)
continue;
if (!(options & WUNTRACED) && !(p->flags & PF_PTRACED))
continue;
if (stat_addr)
put_fs_long((p->exit_code << 8) | 0x7f,
stat_addr);
p->exit_code = 0;
return p->pid;
case TASK_ZOMBIE:
current->cutime += p->utime + p->cutime;
current->cstime += p->stime + p->cstime;
current->cmin_flt += p->min_flt + p->cmin_flt;
current->cmaj_flt += p->maj_flt + p->cmaj_flt;
flag = p->pid;
if (stat_addr)
put_fs_long(p->exit_code, stat_addr);
release(p);
#ifdef DEBUG_PROC_TREE
audit_ptree();
#endif
return flag;
default:
flag=1;
continue;
}
}
if (flag) {
if (options & WNOHANG)
return 0;
current->state=TASK_INTERRUPTIBLE;
oldblocked = current->blocked;
current->blocked &= ~(1<<(SIGCHLD-1));
schedule();
current->blocked = oldblocked;
if (current->signal & ~(current->blocked | (1<<(SIGCHLD-1))))
return -ERESTARTSYS;
else
goto repeat;
}
return -ECHILD;
}
|