freebsd-dev/sys/svr4/svr4_signal.c
Matthew Dillon 279d722604 This patchset fixes a large number of file descriptor race conditions.
Pre-rfork code assumed inherent locking of a process's file descriptor
    array.  However, with the advent of rfork() the file descriptor table
    could be shared between processes.  This patch closes over a dozen
    serious race conditions related to one thread manipulating the table
    (e.g. closing or dup()ing a descriptor) while another is blocked in
    an open(), close(), fcntl(), read(), write(), etc...

PR: kern/11629
Discussed with: Alexander Viro <viro@math.psu.edu>
2000-11-18 21:01:04 +00:00

667 lines
15 KiB
C

/*
* Copyright (c) 1998 Mark Newton
* Copyright (c) 1994 Christos Zoulas
* 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, 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.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission
*
* 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.
*
* $FreeBSD$
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/filedesc.h>
#include <sys/signal.h>
#include <sys/signalvar.h>
#include <sys/sysproto.h>
#include <svr4/svr4.h>
#include <svr4/svr4_types.h>
#include <svr4/svr4_signal.h>
#include <svr4/svr4_proto.h>
#include <svr4/svr4_util.h>
#include <svr4/svr4_ucontext.h>
#define svr4_sigmask(n) (1 << (((n) - 1) & 31))
#define svr4_sigword(n) (((n) - 1) >> 5)
#define svr4_sigemptyset(s) memset((s), 0, sizeof(*(s)))
#define svr4_sigismember(s, n) ((s)->bits[svr4_sigword(n)] & svr4_sigmask(n))
#define svr4_sigaddset(s, n) ((s)->bits[svr4_sigword(n)] |= svr4_sigmask(n))
void svr4_to_bsd_sigaction __P((const struct svr4_sigaction *,
struct sigaction *));
void bsd_to_svr4_sigaction __P((const struct sigaction *,
struct svr4_sigaction *));
void svr4_sigfillset __P((svr4_sigset_t *));
int bsd_to_svr4_sig[SVR4_SIGTBLSZ] = {
SVR4_SIGHUP,
SVR4_SIGINT,
SVR4_SIGQUIT,
SVR4_SIGILL,
SVR4_SIGTRAP,
SVR4_SIGABRT,
SVR4_SIGEMT,
SVR4_SIGFPE,
SVR4_SIGKILL,
SVR4_SIGBUS,
SVR4_SIGSEGV,
SVR4_SIGSYS,
SVR4_SIGPIPE,
SVR4_SIGALRM,
SVR4_SIGTERM,
SVR4_SIGURG,
SVR4_SIGSTOP,
SVR4_SIGTSTP,
SVR4_SIGCONT,
SVR4_SIGCHLD,
SVR4_SIGTTIN,
SVR4_SIGTTOU,
SVR4_SIGIO,
SVR4_SIGXCPU,
SVR4_SIGXFSZ,
SVR4_SIGVTALRM,
SVR4_SIGPROF,
SVR4_SIGWINCH,
0, /* SIGINFO */
SVR4_SIGUSR1,
SVR4_SIGUSR2,
};
int svr4_to_bsd_sig[SVR4_SIGTBLSZ] = {
SIGHUP,
SIGINT,
SIGQUIT,
SIGILL,
SIGTRAP,
SIGABRT,
SIGEMT,
SIGFPE,
SIGKILL,
SIGBUS,
SIGSEGV,
SIGSYS,
SIGPIPE,
SIGALRM,
SIGTERM,
SIGUSR1,
SIGUSR2,
SIGCHLD,
0, /* XXX NetBSD uses SIGPWR here, but we don't seem to have one */
SIGWINCH,
SIGURG,
SIGIO,
SIGSTOP,
SIGTSTP,
SIGCONT,
SIGTTIN,
SIGTTOU,
SIGVTALRM,
SIGPROF,
SIGXCPU,
SIGXFSZ,
};
void
svr4_sigfillset(s)
svr4_sigset_t *s;
{
int i;
svr4_sigemptyset(s);
for (i = 0; i < SVR4_NSIG; i++)
if (svr4_to_bsd_sig[i] != 0)
svr4_sigaddset(s, i);
}
void
svr4_to_bsd_sigset(sss, bss)
const svr4_sigset_t *sss;
sigset_t *bss;
{
int i, newsig;
SIGEMPTYSET(*bss);
for (i = 0; i < SVR4_NSIG; i++)
if (svr4_sigismember(sss, i + 1)) {
newsig = svr4_to_bsd_sig[i];
if (newsig)
SIGADDSET(*bss, newsig);
}
}
void
bsd_to_svr4_sigset(bss, sss)
const sigset_t *bss;
svr4_sigset_t *sss;
{
int i, newsig;
svr4_sigemptyset(sss);
sss->bits[0] = bss->__bits[0] & ~((1U << SVR4_SIGTBLSZ) - 1);
sss->bits[1] = bss->__bits[1];
sss->bits[2] = bss->__bits[2];
sss->bits[3] = bss->__bits[3];
for (i = 1; i <= SVR4_SIGTBLSZ; i++) {
if (SIGISMEMBER(*bss, i)) {
newsig = bsd_to_svr4_sig[_SIG_IDX(i)];
if (newsig)
svr4_sigaddset(sss, newsig);
}
}
}
/*
* XXX: Only a subset of the flags is currently implemented.
*/
void
svr4_to_bsd_sigaction(ssa, bsa)
const struct svr4_sigaction *ssa;
struct sigaction *bsa;
{
bsa->sa_handler = (sig_t) ssa->ssa_handler;
svr4_to_bsd_sigset(&ssa->ssa_mask, &bsa->sa_mask);
bsa->sa_flags = 0;
if ((ssa->ssa_flags & SVR4_SA_ONSTACK) != 0)
bsa->sa_flags |= SA_ONSTACK;
if ((ssa->ssa_flags & SVR4_SA_RESETHAND) != 0)
bsa->sa_flags |= SA_RESETHAND;
if ((ssa->ssa_flags & SVR4_SA_RESTART) != 0)
bsa->sa_flags |= SA_RESTART;
if ((ssa->ssa_flags & SVR4_SA_SIGINFO) != 0)
DPRINTF(("svr4_to_bsd_sigaction: SA_SIGINFO ignored\n"));
if ((ssa->ssa_flags & SVR4_SA_NOCLDSTOP) != 0)
bsa->sa_flags |= SA_NOCLDSTOP;
if ((ssa->ssa_flags & SVR4_SA_NODEFER) != 0)
bsa->sa_flags |= SA_NODEFER;
if ((ssa->ssa_flags & SVR4_SA_NOCLDWAIT) != 0)
bsa->sa_flags |= SA_NOCLDWAIT;
if ((ssa->ssa_flags & ~SVR4_SA_ALLBITS) != 0)
DPRINTF(("svr4_to_bsd_sigaction: extra bits ignored\n"));
}
void
bsd_to_svr4_sigaction(bsa, ssa)
const struct sigaction *bsa;
struct svr4_sigaction *ssa;
{
ssa->ssa_handler = (svr4_sig_t) bsa->sa_handler;
bsd_to_svr4_sigset(&bsa->sa_mask, &ssa->ssa_mask);
ssa->ssa_flags = 0;
if ((bsa->sa_flags & SA_ONSTACK) != 0)
ssa->ssa_flags |= SVR4_SA_ONSTACK;
if ((bsa->sa_flags & SA_RESETHAND) != 0)
ssa->ssa_flags |= SVR4_SA_RESETHAND;
if ((bsa->sa_flags & SA_RESTART) != 0)
ssa->ssa_flags |= SVR4_SA_RESTART;
if ((bsa->sa_flags & SA_NODEFER) != 0)
ssa->ssa_flags |= SVR4_SA_NODEFER;
if ((bsa->sa_flags & SA_NOCLDSTOP) != 0)
ssa->ssa_flags |= SVR4_SA_NOCLDSTOP;
}
void
svr4_to_bsd_sigaltstack(sss, bss)
const struct svr4_sigaltstack *sss;
struct sigaltstack *bss;
{
bss->ss_sp = sss->ss_sp;
bss->ss_size = sss->ss_size;
bss->ss_flags = 0;
if ((sss->ss_flags & SVR4_SS_DISABLE) != 0)
bss->ss_flags |= SS_DISABLE;
if ((sss->ss_flags & SVR4_SS_ONSTACK) != 0)
bss->ss_flags |= SS_ONSTACK;
if ((sss->ss_flags & ~SVR4_SS_ALLBITS) != 0)
/*XXX*/ uprintf("svr4_to_bsd_sigaltstack: extra bits ignored\n");
}
void
bsd_to_svr4_sigaltstack(bss, sss)
const struct sigaltstack *bss;
struct svr4_sigaltstack *sss;
{
sss->ss_sp = bss->ss_sp;
sss->ss_size = bss->ss_size;
sss->ss_flags = 0;
if ((bss->ss_flags & SS_DISABLE) != 0)
sss->ss_flags |= SVR4_SS_DISABLE;
if ((bss->ss_flags & SS_ONSTACK) != 0)
sss->ss_flags |= SVR4_SS_ONSTACK;
}
int
svr4_sys_sigaction(p, uap)
register struct proc *p;
struct svr4_sys_sigaction_args *uap;
{
struct svr4_sigaction *nisa, *oisa, tmpisa;
struct sigaction *nbsa, *obsa, tmpbsa;
struct sigaction_args sa;
caddr_t sg;
int error;
DPRINTF(("@@@ svr4_sys_sigaction(%d, %d, %d)\n", p->p_pid,
SCARG(uap, signum),
SVR4_SVR42BSD_SIG(SCARG(uap, signum))));
sg = stackgap_init();
nisa = SCARG(uap, nsa);
oisa = SCARG(uap, osa);
if (oisa != NULL)
obsa = stackgap_alloc(&sg, sizeof(struct sigaction));
else
obsa = NULL;
if (nisa != NULL) {
nbsa = stackgap_alloc(&sg, sizeof(struct sigaction));
if ((error = copyin(nisa, &tmpisa, sizeof(tmpisa))) != 0)
return error;
svr4_to_bsd_sigaction(&tmpisa, &tmpbsa);
if ((error = copyout(&tmpbsa, nbsa, sizeof(tmpbsa))) != 0)
return error;
} else
nbsa = NULL;
#if defined(DEBUG_SVR4)
{
int i;
for (i = 0; i < 4; i++)
DPRINTF(("\tssa_mask[%d] = %lx\n", i,
nisa->ssa_mask.bits[i]));
DPRINTF(("\tssa_handler = %lx\n", nisa->ssa_handler));
}
#endif
SCARG(&sa, sig) = SVR4_SVR42BSD_SIG(SCARG(uap, signum));
SCARG(&sa, act) = nbsa;
SCARG(&sa, oact) = obsa;
if ((error = sigaction(p, &sa)) != 0)
return error;
if (oisa != NULL) {
if ((error = copyin(obsa, &tmpbsa, sizeof(tmpbsa))) != 0)
return error;
bsd_to_svr4_sigaction(&tmpbsa, &tmpisa);
if ((error = copyout(&tmpisa, oisa, sizeof(tmpisa))) != 0)
return error;
}
return 0;
}
int
svr4_sys_sigaltstack(p, uap)
register struct proc *p;
struct svr4_sys_sigaltstack_args *uap;
{
struct svr4_sigaltstack *nsss, *osss, tmpsss;
struct sigaltstack *nbss, *obss, tmpbss;
struct sigaltstack_args sa;
caddr_t sg;
int error, *retval;
retval = p->p_retval;
sg = stackgap_init();
nsss = SCARG(uap, nss);
osss = SCARG(uap, oss);
if (osss != NULL)
obss = stackgap_alloc(&sg, sizeof(struct sigaltstack));
else
obss = NULL;
if (nsss != NULL) {
nbss = stackgap_alloc(&sg, sizeof(struct sigaltstack));
if ((error = copyin(nsss, &tmpsss, sizeof(tmpsss))) != 0)
return error;
svr4_to_bsd_sigaltstack(&tmpsss, &tmpbss);
if ((error = copyout(&tmpbss, nbss, sizeof(tmpbss))) != 0)
return error;
} else
nbss = NULL;
SCARG(&sa, ss) = nbss;
SCARG(&sa, oss) = obss;
if ((error = sigaltstack(p, &sa)) != 0)
return error;
if (obss != NULL) {
if ((error = copyin(obss, &tmpbss, sizeof(tmpbss))) != 0)
return error;
bsd_to_svr4_sigaltstack(&tmpbss, &tmpsss);
if ((error = copyout(&tmpsss, osss, sizeof(tmpsss))) != 0)
return error;
}
return 0;
}
/*
* Stolen from the ibcs2 one
*/
int
svr4_sys_signal(p, uap)
register struct proc *p;
struct svr4_sys_signal_args *uap;
{
int signum;
int error, *retval = p->p_retval;
caddr_t sg = stackgap_init();
DPRINTF(("@@@ svr4_sys_signal(%d)\n", p->p_pid));
signum = SVR4_SVR42BSD_SIG(SVR4_SIGNO(SCARG(uap, signum)));
if (signum <= 0 || signum > SVR4_NSIG)
return (EINVAL);
switch (SVR4_SIGCALL(SCARG(uap, signum))) {
case SVR4_SIGDEFER_MASK:
if (SCARG(uap, handler) == SVR4_SIG_HOLD)
goto sighold;
/* FALLTHROUGH */
case SVR4_SIGNAL_MASK:
{
struct sigaction_args sa_args;
struct sigaction *nbsa, *obsa, sa;
nbsa = stackgap_alloc(&sg, sizeof(struct sigaction));
obsa = stackgap_alloc(&sg, sizeof(struct sigaction));
SCARG(&sa_args, sig) = signum;
SCARG(&sa_args, act) = nbsa;
SCARG(&sa_args, oact) = obsa;
sa.sa_handler = (sig_t) SCARG(uap, handler);
SIGEMPTYSET(sa.sa_mask);
sa.sa_flags = 0;
if (signum != SIGALRM)
sa.sa_flags = SA_RESTART;
if ((error = copyout(&sa, nbsa, sizeof(sa))) != 0)
return error;
if ((error = sigaction(p, &sa_args)) != 0) {
DPRINTF(("signal: sigaction failed: %d\n",
error));
*retval = (int)SVR4_SIG_ERR;
return error;
}
if ((error = copyin(obsa, &sa, sizeof(sa))) != 0)
return error;
*retval = (int)sa.sa_handler;
return 0;
}
case SVR4_SIGHOLD_MASK:
sighold:
{
struct sigprocmask_args sa;
sigset_t *set;
set = stackgap_alloc(&sg, sizeof(sigset_t));
SIGEMPTYSET(*set);
SIGADDSET(*set, signum);
SCARG(&sa, how) = SIG_BLOCK;
SCARG(&sa, set) = set;
SCARG(&sa, oset) = NULL;
return sigprocmask(p, &sa);
}
case SVR4_SIGRELSE_MASK:
{
struct sigprocmask_args sa;
sigset_t *set;
set = stackgap_alloc(&sg, sizeof(sigset_t));
SIGEMPTYSET(*set);
SIGADDSET(*set, signum);
SCARG(&sa, how) = SIG_UNBLOCK;
SCARG(&sa, set) = set;
SCARG(&sa, oset) = NULL;
return sigprocmask(p, &sa);
}
case SVR4_SIGIGNORE_MASK:
{
struct sigaction_args sa_args;
struct sigaction *bsa, sa;
bsa = stackgap_alloc(&sg, sizeof(struct sigaction));
SCARG(&sa_args, sig) = signum;
SCARG(&sa_args, act) = bsa;
SCARG(&sa_args, oact) = NULL;
sa.sa_handler = SIG_IGN;
SIGEMPTYSET(sa.sa_mask);
sa.sa_flags = 0;
if ((error = copyout(&sa, bsa, sizeof(sa))) != 0)
return error;
if ((error = sigaction(p, &sa_args)) != 0) {
DPRINTF(("sigignore: sigaction failed\n"));
return error;
}
return 0;
}
case SVR4_SIGPAUSE_MASK:
{
struct sigsuspend_args sa;
sigset_t *set;
set = stackgap_alloc(&sg, sizeof(sigset_t));
*set = p->p_sigmask;
SIGDELSET(*set, signum);
SCARG(&sa, sigmask) = set;
return sigsuspend(p, &sa);
}
default:
return (ENOSYS);
}
}
int
svr4_sys_sigprocmask(p, uap)
struct proc *p;
struct svr4_sys_sigprocmask_args *uap;
{
svr4_sigset_t sss;
sigset_t bss;
int error = 0, *retval;
retval = p->p_retval;
if (SCARG(uap, oset) != NULL) {
/* Fix the return value first if needed */
bsd_to_svr4_sigset(&p->p_sigmask, &sss);
if ((error = copyout(&sss, SCARG(uap, oset), sizeof(sss))) != 0)
return error;
}
if (SCARG(uap, set) == NULL)
/* Just examine */
return 0;
if ((error = copyin(SCARG(uap, set), &sss, sizeof(sss))) != 0)
return error;
svr4_to_bsd_sigset(&sss, &bss);
mtx_enter_sched_quick();
switch (SCARG(uap, how)) {
case SVR4_SIG_BLOCK:
SIGSETOR(p->p_sigmask, bss);
SIG_CANTMASK(p->p_sigmask);
break;
case SVR4_SIG_UNBLOCK:
SIGSETNAND(p->p_sigmask, bss);
break;
case SVR4_SIG_SETMASK:
p->p_sigmask = bss;
SIG_CANTMASK(p->p_sigmask);
break;
default:
error = EINVAL;
break;
}
mtx_exit_sched_quick();
return error;
}
int
svr4_sys_sigpending(p, uap)
struct proc *p;
struct svr4_sys_sigpending_args *uap;
{
sigset_t bss;
int *retval;
svr4_sigset_t sss;
DPRINTF(("@@@ svr4_sys_sigpending(%d)\n", p->p_pid));
retval = p->p_retval;
switch (SCARG(uap, what)) {
case 1: /* sigpending */
if (SCARG(uap, mask) == NULL)
return 0;
bss = p->p_siglist;
SIGSETAND(bss, p->p_sigmask);
bsd_to_svr4_sigset(&bss, &sss);
break;
case 2: /* sigfillset */
svr4_sigfillset(&sss);
#if defined(DEBUG_SVR4)
{
int i;
for (i = 0; i < 4; i++)
DPRINTF(("new sigset[%d] = %lx\n", i, (long)sss.bits[i]));
}
#endif
break;
default:
return EINVAL;
}
return copyout(&sss, SCARG(uap, mask), sizeof(sss));
}
int
svr4_sys_sigsuspend(p, uap)
register struct proc *p;
struct svr4_sys_sigsuspend_args *uap;
{
svr4_sigset_t sss;
sigset_t *bss;
struct sigsuspend_args sa;
int error;
caddr_t sg = stackgap_init();
if ((error = copyin(SCARG(uap, ss), &sss, sizeof(sss))) != 0)
return error;
bss = stackgap_alloc(&sg, sizeof(sigset_t));
svr4_to_bsd_sigset(&sss, bss);
SCARG(&sa, sigmask) = bss;
return sigsuspend(p, &sa);
}
int
svr4_sys_kill(p, uap)
register struct proc *p;
struct svr4_sys_kill_args *uap;
{
struct kill_args ka;
SCARG(&ka, pid) = SCARG(uap, pid);
SCARG(&ka, signum) = SVR4_SVR42BSD_SIG(SCARG(uap, signum));
return kill(p, &ka);
}
int
svr4_sys_context(p, uap)
register struct proc *p;
struct svr4_sys_context_args *uap;
{
struct svr4_ucontext uc;
int error;
switch (uap->func) {
case 0:
DPRINTF(("getcontext(%p)\n", uap->uc));
svr4_getcontext(p, &uc, &p->p_sigmask,
p->p_sigstk.ss_flags & SS_ONSTACK);
return copyout(&uc, uap->uc, sizeof(uc));
case 1:
DPRINTF(("setcontext(%p)\n", uap->uc));
if ((error = copyin(uap->uc, &uc, sizeof(uc))) != 0)
return error;
DPRINTF(("uc_flags = %lx\n", uc.uc_flags));
#if defined(DEBUG_SVR4)
{
int i;
for (i = 0; i < 4; i++)
DPRINTF(("uc_sigmask[%d] = %lx\n", i,
uc.uc_sigmask.bits[i]));
}
#endif
return svr4_setcontext(p, &uc);
default:
DPRINTF(("context(%d, %p)\n", uap->func,
uap->uc));
return ENOSYS;
}
return 0;
}
int
svr4_sys_pause(p, uap)
register struct proc *p;
struct svr4_sys_pause_args *uap;
{
struct sigsuspend_args bsa;
SCARG(&bsa, sigmask) = &p->p_sigmask;
return sigsuspend(p, &bsa);
}