freebsd-dev/sys/kern/kern_thr.c
Ed Schouten c90c9021e9 Remove even more unneeded variable assignments.
kern_time.c:
- Unused variable `p'.

kern_thr.c:
- Variable `error' is always caught immediately, so no reason to
  initialize it. There is no way that error != 0 at the end of
  create_thread().

kern_sig.c:
- Unused variable `code'.

kern_synch.c:
- `rval' is always assigned in all different cases.

kern_rwlock.c:
- `v' is always overwritten with RW_UNLOCKED further on.

kern_malloc.c:
- `size' is always initialized with the proper value before being used.

kern_exit.c:
- `error' is always caught and returned immediately. abort2() never
  returns a non-zero value.

kern_exec.c:
- `len' is always assigned inside the if-statement right below it.

tty_info.c:
- `td' is always overwritten by FOREACH_THREAD_IN_PROC().

Found by:	LLVM's scan-build
2009-02-26 15:51:54 +00:00

513 lines
12 KiB
C

/*-
* Copyright (c) 2003, Jeffrey Roberson <jeff@freebsd.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice unmodified, this list of conditions, and the following
* disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_compat.h"
#include "opt_posix.h"
#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/priv.h>
#include <sys/proc.h>
#include <sys/posix4.h>
#include <sys/resourcevar.h>
#include <sys/sched.h>
#include <sys/sysctl.h>
#include <sys/smp.h>
#include <sys/syscallsubr.h>
#include <sys/sysent.h>
#include <sys/systm.h>
#include <sys/sysproto.h>
#include <sys/signalvar.h>
#include <sys/ucontext.h>
#include <sys/thr.h>
#include <sys/rtprio.h>
#include <sys/umtx.h>
#include <sys/limits.h>
#include <machine/frame.h>
#include <security/audit/audit.h>
#ifdef COMPAT_IA32
static inline int
suword_lwpid(void *addr, lwpid_t lwpid)
{
int error;
if (SV_CURPROC_FLAG(SV_LP64))
error = suword(addr, lwpid);
else
error = suword32(addr, lwpid);
return (error);
}
#else
#define suword_lwpid suword
#endif
extern int max_threads_per_proc;
extern int max_threads_hits;
static int create_thread(struct thread *td, mcontext_t *ctx,
void (*start_func)(void *), void *arg,
char *stack_base, size_t stack_size,
char *tls_base,
long *child_tid, long *parent_tid,
int flags, struct rtprio *rtp);
/*
* System call interface.
*/
int
thr_create(struct thread *td, struct thr_create_args *uap)
/* ucontext_t *ctx, long *id, int flags */
{
ucontext_t ctx;
int error;
if ((error = copyin(uap->ctx, &ctx, sizeof(ctx))))
return (error);
error = create_thread(td, &ctx.uc_mcontext, NULL, NULL,
NULL, 0, NULL, uap->id, NULL, uap->flags, NULL);
return (error);
}
int
thr_new(struct thread *td, struct thr_new_args *uap)
/* struct thr_param * */
{
struct thr_param param;
int error;
if (uap->param_size < 0 || uap->param_size > sizeof(param))
return (EINVAL);
bzero(&param, sizeof(param));
if ((error = copyin(uap->param, &param, uap->param_size)))
return (error);
return (kern_thr_new(td, &param));
}
int
kern_thr_new(struct thread *td, struct thr_param *param)
{
struct rtprio rtp, *rtpp;
int error;
rtpp = NULL;
if (param->rtp != 0) {
error = copyin(param->rtp, &rtp, sizeof(struct rtprio));
if (error)
return (error);
rtpp = &rtp;
}
error = create_thread(td, NULL, param->start_func, param->arg,
param->stack_base, param->stack_size, param->tls_base,
param->child_tid, param->parent_tid, param->flags,
rtpp);
return (error);
}
static int
create_thread(struct thread *td, mcontext_t *ctx,
void (*start_func)(void *), void *arg,
char *stack_base, size_t stack_size,
char *tls_base,
long *child_tid, long *parent_tid,
int flags, struct rtprio *rtp)
{
stack_t stack;
struct thread *newtd;
struct proc *p;
int error;
p = td->td_proc;
/* Have race condition but it is cheap. */
if (p->p_numthreads >= max_threads_per_proc) {
++max_threads_hits;
return (EPROCLIM);
}
if (rtp != NULL) {
switch(rtp->type) {
case RTP_PRIO_REALTIME:
case RTP_PRIO_FIFO:
/* Only root can set scheduler policy */
if (priv_check(td, PRIV_SCHED_SETPOLICY) != 0)
return (EPERM);
if (rtp->prio > RTP_PRIO_MAX)
return (EINVAL);
break;
case RTP_PRIO_NORMAL:
rtp->prio = 0;
break;
default:
return (EINVAL);
}
}
/* Initialize our td */
newtd = thread_alloc();
if (newtd == NULL)
return (ENOMEM);
/*
* Try the copyout as soon as we allocate the td so we don't
* have to tear things down in a failure case below.
* Here we copy out tid to two places, one for child and one
* for parent, because pthread can create a detached thread,
* if parent wants to safely access child tid, it has to provide
* its storage, because child thread may exit quickly and
* memory is freed before parent thread can access it.
*/
if ((child_tid != NULL &&
suword_lwpid(child_tid, newtd->td_tid)) ||
(parent_tid != NULL &&
suword_lwpid(parent_tid, newtd->td_tid))) {
thread_free(newtd);
return (EFAULT);
}
bzero(&newtd->td_startzero,
__rangeof(struct thread, td_startzero, td_endzero));
bcopy(&td->td_startcopy, &newtd->td_startcopy,
__rangeof(struct thread, td_startcopy, td_endcopy));
newtd->td_proc = td->td_proc;
newtd->td_ucred = crhold(td->td_ucred);
cpu_set_upcall(newtd, td);
if (ctx != NULL) { /* old way to set user context */
error = set_mcontext(newtd, ctx);
if (error != 0) {
thread_free(newtd);
crfree(td->td_ucred);
return (error);
}
} else {
/* Set up our machine context. */
stack.ss_sp = stack_base;
stack.ss_size = stack_size;
/* Set upcall address to user thread entry function. */
cpu_set_upcall_kse(newtd, start_func, arg, &stack);
/* Setup user TLS address and TLS pointer register. */
error = cpu_set_user_tls(newtd, tls_base);
if (error != 0) {
thread_free(newtd);
crfree(td->td_ucred);
return (error);
}
}
PROC_LOCK(td->td_proc);
td->td_proc->p_flag |= P_HADTHREADS;
newtd->td_sigmask = td->td_sigmask;
thread_link(newtd, p);
bcopy(p->p_comm, newtd->td_name, sizeof(newtd->td_name));
thread_lock(td);
/* let the scheduler know about these things. */
sched_fork_thread(td, newtd);
thread_unlock(td);
if (P_SHOULDSTOP(p))
newtd->td_flags |= TDF_ASTPENDING | TDF_NEEDSUSPCHK;
PROC_UNLOCK(p);
thread_lock(newtd);
if (rtp != NULL) {
if (!(td->td_pri_class == PRI_TIMESHARE &&
rtp->type == RTP_PRIO_NORMAL)) {
rtp_to_pri(rtp, newtd);
sched_prio(newtd, newtd->td_user_pri);
} /* ignore timesharing class */
}
TD_SET_CAN_RUN(newtd);
sched_add(newtd, SRQ_BORING);
thread_unlock(newtd);
return (0);
}
int
thr_self(struct thread *td, struct thr_self_args *uap)
/* long *id */
{
int error;
error = suword_lwpid(uap->id, (unsigned)td->td_tid);
if (error == -1)
return (EFAULT);
return (0);
}
int
thr_exit(struct thread *td, struct thr_exit_args *uap)
/* long *state */
{
struct proc *p;
p = td->td_proc;
/* Signal userland that it can free the stack. */
if ((void *)uap->state != NULL) {
suword_lwpid(uap->state, 1);
kern_umtx_wake(td, uap->state, INT_MAX, 0);
}
PROC_LOCK(p);
sigqueue_flush(&td->td_sigqueue);
PROC_SLOCK(p);
/*
* Shutting down last thread in the proc. This will actually
* call exit() in the trampoline when it returns.
*/
if (p->p_numthreads != 1) {
thread_stopped(p);
thread_exit();
/* NOTREACHED */
}
PROC_SUNLOCK(p);
PROC_UNLOCK(p);
return (0);
}
int
thr_kill(struct thread *td, struct thr_kill_args *uap)
/* long id, int sig */
{
struct thread *ttd;
struct proc *p;
int error;
p = td->td_proc;
error = 0;
PROC_LOCK(p);
if (uap->id == -1) {
if (uap->sig != 0 && !_SIG_VALID(uap->sig)) {
error = EINVAL;
} else {
error = ESRCH;
FOREACH_THREAD_IN_PROC(p, ttd) {
if (ttd != td) {
error = 0;
if (uap->sig == 0)
break;
tdsignal(p, ttd, uap->sig, NULL);
}
}
}
} else {
if (uap->id != td->td_tid)
ttd = thread_find(p, uap->id);
else
ttd = td;
if (ttd == NULL)
error = ESRCH;
else if (uap->sig == 0)
;
else if (!_SIG_VALID(uap->sig))
error = EINVAL;
else
tdsignal(p, ttd, uap->sig, NULL);
}
PROC_UNLOCK(p);
return (error);
}
int
thr_kill2(struct thread *td, struct thr_kill2_args *uap)
/* pid_t pid, long id, int sig */
{
struct thread *ttd;
struct proc *p;
int error;
AUDIT_ARG(signum, uap->sig);
if (uap->pid == td->td_proc->p_pid) {
p = td->td_proc;
PROC_LOCK(p);
} else if ((p = pfind(uap->pid)) == NULL) {
return (ESRCH);
}
AUDIT_ARG(process, p);
error = p_cansignal(td, p, uap->sig);
if (error == 0) {
if (uap->id == -1) {
if (uap->sig != 0 && !_SIG_VALID(uap->sig)) {
error = EINVAL;
} else {
error = ESRCH;
FOREACH_THREAD_IN_PROC(p, ttd) {
if (ttd != td) {
error = 0;
if (uap->sig == 0)
break;
tdsignal(p, ttd, uap->sig, NULL);
}
}
}
} else {
if (uap->id != td->td_tid)
ttd = thread_find(p, uap->id);
else
ttd = td;
if (ttd == NULL)
error = ESRCH;
else if (uap->sig == 0)
;
else if (!_SIG_VALID(uap->sig))
error = EINVAL;
else
tdsignal(p, ttd, uap->sig, NULL);
}
}
PROC_UNLOCK(p);
return (error);
}
int
thr_suspend(struct thread *td, struct thr_suspend_args *uap)
/* const struct timespec *timeout */
{
struct timespec ts, *tsp;
int error;
tsp = NULL;
if (uap->timeout != NULL) {
error = copyin((const void *)uap->timeout, (void *)&ts,
sizeof(struct timespec));
if (error != 0)
return (error);
tsp = &ts;
}
return (kern_thr_suspend(td, tsp));
}
int
kern_thr_suspend(struct thread *td, struct timespec *tsp)
{
struct timeval tv;
int error = 0, hz = 0;
if (tsp != NULL) {
if (tsp->tv_nsec < 0 || tsp->tv_nsec > 1000000000)
return (EINVAL);
if (tsp->tv_sec == 0 && tsp->tv_nsec == 0)
return (ETIMEDOUT);
TIMESPEC_TO_TIMEVAL(&tv, tsp);
hz = tvtohz(&tv);
}
if (td->td_pflags & TDP_WAKEUP) {
td->td_pflags &= ~TDP_WAKEUP;
return (0);
}
PROC_LOCK(td->td_proc);
if ((td->td_flags & TDF_THRWAKEUP) == 0)
error = msleep((void *)td, &td->td_proc->p_mtx, PCATCH, "lthr",
hz);
if (td->td_flags & TDF_THRWAKEUP) {
thread_lock(td);
td->td_flags &= ~TDF_THRWAKEUP;
thread_unlock(td);
PROC_UNLOCK(td->td_proc);
return (0);
}
PROC_UNLOCK(td->td_proc);
if (error == EWOULDBLOCK)
error = ETIMEDOUT;
else if (error == ERESTART) {
if (hz != 0)
error = EINTR;
}
return (error);
}
int
thr_wake(struct thread *td, struct thr_wake_args *uap)
/* long id */
{
struct proc *p;
struct thread *ttd;
if (uap->id == td->td_tid) {
td->td_pflags |= TDP_WAKEUP;
return (0);
}
p = td->td_proc;
PROC_LOCK(p);
ttd = thread_find(p, uap->id);
if (ttd == NULL) {
PROC_UNLOCK(p);
return (ESRCH);
}
thread_lock(ttd);
ttd->td_flags |= TDF_THRWAKEUP;
thread_unlock(ttd);
wakeup((void *)ttd);
PROC_UNLOCK(p);
return (0);
}
int
thr_set_name(struct thread *td, struct thr_set_name_args *uap)
{
struct proc *p = td->td_proc;
char name[MAXCOMLEN + 1];
struct thread *ttd;
int error;
error = 0;
name[0] = '\0';
if (uap->name != NULL) {
error = copyinstr(uap->name, name, sizeof(name),
NULL);
if (error)
return (error);
}
PROC_LOCK(p);
if (uap->id == td->td_tid)
ttd = td;
else
ttd = thread_find(p, uap->id);
if (ttd != NULL)
strcpy(ttd->td_name, name);
else
error = ESRCH;
PROC_UNLOCK(p);
return (error);
}