d/freebsd-dev
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Among signal generation syscalls, only sigqueue(2) is allowed by POSIX

Browse Source 
to fail due to lack of resources to queue siginfo. Add KSI_SIGQ flag
that allows sigqueue_add() to fail while trying to allocate memory for
new siginfo. When the flag is not set, behaviour is the same as for
KSI_TRAP: if memory cannot be allocated, set bit in sq_kill. KSI_TRAP is
kept to preserve KBI.

Add SI_KERNEL si_code, to be used in siginfo.si_code when signal is
generated by kernel. Deliver siginfo when signal is generated by kill(2)
family of syscalls (SI_USER with properly filled si_uid and si_pid), or
by kernel (SI_KERNEL, mostly job control or SIGIO). Since KSI_SIGQ flag
is not set for the ksi, low memory condition cause old behaviour.

Keep psignal(9) KBI intact, but modify it to generate SI_KERNEL
si_code. Pgsignal(9) and gsignal(9) now take ksi explicitely. Add
pksignal(9) that behaves like psignal but takes ksi, and ddb kill
command implemented as pksignal(..., ksi = NULL) to not do allocation
while in debugger.

While there, remove some register specifiers and use ANSI C prototypes.

Reviewed by:	davidxu
MFC after:	1 month
This commit is contained in:
Konstantin Belousov 2009-11-17 11:39:15 +00:00
parent 5b412ffb6b
commit a3de221dbe
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=199355
5 changed files with 74 additions and 35 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
sys/ddb/db_command.c
View File

@ -652,7 +652,7 @@ db_kill(dummy1, dummy2, dummy3, dummy4)
if (PROC_TRYLOCK(p) == 0)
DB_ERROR(("Can't lock process with pid %ld\n", (long) pid));
else {
psignal(p, sig);
pksignal(p, sig, NULL);
PROC_UNLOCK(p);
}

82
sys/kern/kern_sig.c
View File

@ -99,7 +99,8 @@ SDT_PROBE_ARGTYPE(proc, kernel, , signal_discard, 2, "int");
static int coredump(struct thread *);
static char *expand_name(const char *, uid_t, pid_t);
static int killpg1(struct thread *td, int sig, int pgid, int all);
static int killpg1(struct thread *td, int sig, int pgid, int all,
ksiginfo_t *ksi);
static int issignal(struct thread *td, int stop_allowed);
static int sigprop(int sig);
static void tdsigwakeup(struct thread *, int, sig_t, int);
@ -381,7 +382,8 @@ sigqueue_add(sigqueue_t *sq, int signo, ksiginfo_t *si)
ksi->ksi_sigq = sq;
}
if ((si->ksi_flags & KSI_TRAP) != 0) {
if ((si->ksi_flags & KSI_TRAP) != 0 ||
(si->ksi_flags & KSI_SIGQ) == 0) {
if (ret != 0)
SIGADDSET(sq->sq_kill, signo);
ret = 0;
@ -1611,11 +1613,9 @@ kern_sigaltstack(struct thread *td, stack_t *ss, stack_t *oss)
* cp is calling process.
*/
static int
killpg1(td, sig, pgid, all)
register struct thread *td;
int sig, pgid, all;
killpg1(struct thread *td, int sig, int pgid, int all, ksiginfo_t *ksi)
{
register struct proc *p;
struct proc *p;
struct pgrp *pgrp;
int nfound = 0;
@ -1634,7 +1634,7 @@ killpg1(td, sig, pgid, all)
if (p_cansignal(td, p, sig) == 0) {
nfound++;
if (sig)
psignal(p, sig);
pksignal(p, sig, ksi);
}
PROC_UNLOCK(p);
}
@ -1665,7 +1665,7 @@ killpg1(td, sig, pgid, all)
if (p_cansignal(td, p, sig) == 0) {
nfound++;
if (sig)
psignal(p, sig);
pksignal(p, sig, ksi);
}
PROC_UNLOCK(p);
}
@ -1682,11 +1682,10 @@ struct kill_args {
#endif
/* ARGSUSED */
int
kill(td, uap)
register struct thread *td;
register struct kill_args *uap;
kill(struct thread *td, struct kill_args *uap)
{
register struct proc *p;
ksiginfo_t ksi;
struct proc *p;
int error;
AUDIT_ARG_SIGNUM(uap->signum);
@ -1694,6 +1693,12 @@ kill(td, uap)
if ((u_int)uap->signum > _SIG_MAXSIG)
return (EINVAL);
ksiginfo_init(&ksi);
ksi.ksi_signo = uap->signum;
ksi.ksi_code = SI_USER;
ksi.ksi_pid = td->td_proc->p_pid;
ksi.ksi_uid = td->td_ucred->cr_ruid;
if (uap->pid > 0) {
/* kill single process */
if ((p = pfind(uap->pid)) == NULL) {
@ -1703,17 +1708,17 @@ kill(td, uap)
AUDIT_ARG_PROCESS(p);
error = p_cansignal(td, p, uap->signum);
if (error == 0 && uap->signum)
psignal(p, uap->signum);
pksignal(p, uap->signum, &ksi);
PROC_UNLOCK(p);
return (error);
}
switch (uap->pid) {
case -1: /* broadcast signal */
return (killpg1(td, uap->signum, 0, 1));
return (killpg1(td, uap->signum, 0, 1, &ksi));
case 0: /* signal own process group */
return (killpg1(td, uap->signum, 0, 0));
return (killpg1(td, uap->signum, 0, 0, &ksi));
default: /* negative explicit process group */
return (killpg1(td, uap->signum, -uap->pid, 0));
return (killpg1(td, uap->signum, -uap->pid, 0, &ksi));
}
/* NOTREACHED */
}
@ -1727,17 +1732,21 @@ struct okillpg_args {
#endif
/* ARGSUSED */
int
okillpg(td, uap)
struct thread *td;
register struct okillpg_args *uap;
okillpg(struct thread *td, struct okillpg_args *uap)
{
ksiginfo_t ksi;
AUDIT_ARG_SIGNUM(uap->signum);
AUDIT_ARG_PID(uap->pgid);
if ((u_int)uap->signum > _SIG_MAXSIG)
return (EINVAL);
return (killpg1(td, uap->signum, uap->pgid, 0));
ksiginfo_init(&ksi);
ksi.ksi_signo = uap->signum;
ksi.ksi_code = SI_USER;
ksi.ksi_pid = td->td_proc->p_pid;
ksi.ksi_uid = td->td_ucred->cr_ruid;
return (killpg1(td, uap->signum, uap->pgid, 0, &ksi));
}
#endif /* COMPAT_43 */
@ -1772,6 +1781,7 @@ sigqueue(struct thread *td, struct sigqueue_args *uap)
error = p_cansignal(td, p, uap->signum);
if (error == 0 && uap->signum != 0) {
ksiginfo_init(&ksi);
ksi.ksi_flags = KSI_SIGQ;
ksi.ksi_signo = uap->signum;
ksi.ksi_code = SI_QUEUE;
ksi.ksi_pid = td->td_proc->p_pid;
@ -1787,8 +1797,7 @@ sigqueue(struct thread *td, struct sigqueue_args *uap)
* Send a signal to a process group.
*/
void
gsignal(pgid, sig)
int pgid, sig;
gsignal(int pgid, int sig, ksiginfo_t *ksi)
{
struct pgrp *pgrp;
@ -1797,7 +1806,7 @@ gsignal(pgid, sig)
pgrp = pgfind(pgid);
sx_sunlock(&proctree_lock);
if (pgrp != NULL) {
pgsignal(pgrp, sig, 0);
pgsignal(pgrp, sig, 0, ksi);
PGRP_UNLOCK(pgrp);
}
}
@ -1808,18 +1817,16 @@ gsignal(pgid, sig)
* limit to members which have a controlling terminal.
*/
void
pgsignal(pgrp, sig, checkctty)
struct pgrp *pgrp;
int sig, checkctty;
pgsignal(struct pgrp *pgrp, int sig, int checkctty, ksiginfo_t *ksi)
{
register struct proc *p;
struct proc *p;
if (pgrp) {
PGRP_LOCK_ASSERT(pgrp, MA_OWNED);
LIST_FOREACH(p, &pgrp->pg_members, p_pglist) {
PROC_LOCK(p);
if (checkctty == 0 || p->p_flag & P_CONTROLT)
psignal(p, sig);
pksignal(p, sig, ksi);
PROC_UNLOCK(p);
}
}
@ -1940,7 +1947,19 @@ sigtd(struct proc *p, int sig, int prop)
void
psignal(struct proc *p, int sig)
{
(void) tdsignal(p, NULL, sig, NULL);
ksiginfo_t ksi;
ksiginfo_init(&ksi);
ksi.ksi_signo = sig;
ksi.ksi_code = SI_KERNEL;
(void) tdsignal(p, NULL, sig, &ksi);
}
void
pksignal(struct proc *p, int sig, ksiginfo_t *ksi)
{
(void) tdsignal(p, NULL, sig, ksi);
}
int
@ -3143,8 +3162,13 @@ pgsigio(sigiop, sig, checkctty)
struct sigio **sigiop;
int sig, checkctty;
{
ksiginfo_t ksi;
struct sigio *sigio;
ksiginfo_init(&ksi);
ksi.ksi_signo = sig;
ksi.ksi_code = SI_KERNEL;
SIGIO_LOCK();
sigio = *sigiop;
if (sigio == NULL) {

16
sys/kern/tty.c
View File

@ -355,6 +355,7 @@ tty_wait_background(struct tty *tp, struct thread *td, int sig)
{
struct proc *p = td->td_proc;
struct pgrp *pg;
ksiginfo_t ksi;
int error;
MPASS(sig == SIGTTIN || sig == SIGTTOU);
@ -396,8 +397,14 @@ tty_wait_background(struct tty *tp, struct thread *td, int sig)
* Send the signal and sleep until we're the new
* foreground process group.
*/
if (sig != 0) {
ksiginfo_init(&ksi);
ksi.ksi_code = SI_KERNEL;
ksi.ksi_signo = sig;
sig = 0;
}
PGRP_LOCK(pg);
pgsignal(pg, sig, 1);
pgsignal(pg, ksi.ksi_signo, 1, &ksi);
PGRP_UNLOCK(pg);
error = tty_wait(tp, &tp->t_bgwait);
@ -1240,6 +1247,8 @@ tty_signal_sessleader(struct tty *tp, int sig)
void
tty_signal_pgrp(struct tty *tp, int sig)
{
ksiginfo_t ksi;
tty_lock_assert(tp, MA_OWNED);
MPASS(sig >= 1 && sig < NSIG);
@ -1249,8 +1258,11 @@ tty_signal_pgrp(struct tty *tp, int sig)
if (sig == SIGINFO && !(tp->t_termios.c_lflag & NOKERNINFO))
tty_info(tp);
if (tp->t_pgrp != NULL) {
ksiginfo_init(&ksi);
ksi.ksi_signo = sig;
ksi.ksi_code = SI_KERNEL;
PGRP_LOCK(tp->t_pgrp);
pgsignal(tp->t_pgrp, sig, 1);
pgsignal(tp->t_pgrp, sig, 1, &ksi);
PGRP_UNLOCK(tp->t_pgrp);
}
}

1
sys/sys/signal.h
View File

@ -338,6 +338,7 @@ struct sigaction {
/* an asynchronous I/O request.*/
#define SI_MESGQ 0x10005 /* Signal generated by arrival of a */
/* message on an empty message queue. */
#define SI_KERNEL 0x10006
#endif
#if __BSD_VISIBLE
#define SI_UNDEFINED 0

8
sys/sys/signalvar.h
View File

@ -233,7 +233,8 @@ typedef struct ksiginfo {
#define KSI_TRAP 0x01 /* Generated by trap. */
#define KSI_EXT 0x02 /* Externally managed ksi. */
#define KSI_INS 0x04 /* Directly insert ksi, not the copy */
#define KSI_COPYMASK KSI_TRAP
#define KSI_SIGQ 0x08 /* Generated by sigqueue, might ret EGAIN. */
#define KSI_COPYMASK (KSI_TRAP|KSI_SIGQ)
#define KSI_ONQ(ksi) ((ksi)->ksi_sigq != NULL)
@ -326,10 +327,11 @@ extern int kern_logsigexit; /* Sysctl variable kern.logsigexit */
*/
int cursig(struct thread *td, int stop_allowed);
void execsigs(struct proc *p);
void gsignal(int pgid, int sig);
void gsignal(int pgid, int sig, ksiginfo_t *ksi);
void killproc(struct proc *p, char *why);
void pksignal(struct proc *p, int sig, ksiginfo_t *ksi);
void pgsigio(struct sigio **, int signum, int checkctty);
void pgsignal(struct pgrp *pgrp, int sig, int checkctty);
void pgsignal(struct pgrp *pgrp, int sig, int checkctty, ksiginfo_t *ksi);
int postsig(int sig);
void psignal(struct proc *p, int sig);
int psignal_event(struct proc *p, struct sigevent *, ksiginfo_t *);