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Index: lib/libc/sys/sigqueue.2
===================================================================
--- lib/libc/sys/sigqueue.2
+++ lib/libc/sys/sigqueue.2
@@ -27,7 +27,7 @@
.\"
.\" $FreeBSD$
.\"
-.Dd March 10, 2012
+.Dd May 5, 2017
.Dt SIGQUEUE 2
.Os
.Sh NAME
@@ -129,7 +129,6 @@
.Xr kill 2 ,
.Xr sigaction 2 ,
.Xr sigpending 2 ,
-.Xr sigqueue 2 ,
.Xr sigsuspend 2 ,
.Xr sigtimedwait 2 ,
.Xr sigwait 2 ,
@@ -147,3 +146,18 @@
.Tn POSIX
realtime signal queue first appeared in
.Fx 7.0 .
+.Sh CAVEATS
+When using
+.Nm
+to send signals to a process which might have a different ABI
+(for instance, one is 32-bit and the other 64-bit),
+the
+.Va sival_int
+member of
+.Fa value
+can be delivered reliably, but the
+.Va sival_ptr
+may be truncated in endian dependent ways and must not be relied on.
+Further, many pointer integrity schemes disallow sending pointers to other
+processes, and this technique should not be used in programs intended to
+be portable.
Index: sys/compat/freebsd32/freebsd32_misc.c
===================================================================
--- sys/compat/freebsd32/freebsd32_misc.c
+++ sys/compat/freebsd32/freebsd32_misc.c
@@ -2477,6 +2477,32 @@
dst->si_overrun = src->si_overrun;
}
+#ifndef _FREEBSD32_SYSPROTO_H_
+struct freebsd32_sigqueue_args {
+ pid_t pid;
+ int signum;
+ /* union sigval32 */ int value;
+};
+#endif
+int
+freebsd32_sigqueue(struct thread *td, struct freebsd32_sigqueue_args *uap)
+{
+ union sigval sv;
+
+ /*
+ * On 32-bit ABIs, sival_int and sival_ptr are the same.
+ * On 64-bit little-endian ABIs, the low bits are the same.
+ * In 64-bit big-endian ABIs, sival_int overlaps with
+ * sival_ptr's HIGH bits. We choose to support sival_int
+ * rather than sival_ptr in this case as it seems to be
+ * more common.
+ */
+ bzero(&sv, sizeof(sv));
+ sv.sival_int = uap->value;
+
+ return (kern_sigqueue(td, uap->pid, uap->signum, &sv));
+}
+
int
freebsd32_sigtimedwait(struct thread *td, struct freebsd32_sigtimedwait_args *uap)
{
Index: sys/compat/freebsd32/syscalls.master
===================================================================
--- sys/compat/freebsd32/syscalls.master
+++ sys/compat/freebsd32/syscalls.master
@@ -819,8 +819,8 @@
455 AUE_THR_NEW STD { int freebsd32_thr_new( \
struct thr_param32 *param, \
int param_size); }
-456 AUE_NULL NOPROTO { int sigqueue(pid_t pid, int signum, \
- void *value); }
+456 AUE_NULL STD { int freebsd32_sigqueue(pid_t pid, \
+ int signum, int value); }
457 AUE_MQ_OPEN NOSTD { int freebsd32_kmq_open( \
const char *path, int flags, mode_t mode, \
const struct mq_attr32 *attr); }
Index: sys/kern/kern_sig.c
===================================================================
--- sys/kern/kern_sig.c
+++ sys/kern/kern_sig.c
@@ -1844,33 +1844,43 @@
int
sys_sigqueue(struct thread *td, struct sigqueue_args *uap)
{
+ union sigval sv;
+
+ sv.sival_ptr = uap->value;
+
+ return (kern_sigqueue(td, uap->pid, uap->signum, &sv));
+}
+
+int
+kern_sigqueue(struct thread *td, pid_t pid, int signum, union sigval *value)
+{
ksiginfo_t ksi;
struct proc *p;
int error;
- if ((u_int)uap->signum > _SIG_MAXSIG)
+ if ((u_int)signum > _SIG_MAXSIG)
return (EINVAL);
/*
* Specification says sigqueue can only send signal to
* single process.
*/
- if (uap->pid <= 0)
+ if (pid <= 0)
return (EINVAL);
- if ((p = pfind(uap->pid)) == NULL) {
- if ((p = zpfind(uap->pid)) == NULL)
+ if ((p = pfind(pid)) == NULL) {
+ if ((p = zpfind(pid)) == NULL)
return (ESRCH);
}
- error = p_cansignal(td, p, uap->signum);
- if (error == 0 && uap->signum != 0) {
+ error = p_cansignal(td, p, signum);
+ if (error == 0 && signum != 0) {
ksiginfo_init(&ksi);
ksi.ksi_flags = KSI_SIGQ;
- ksi.ksi_signo = uap->signum;
+ ksi.ksi_signo = signum;
ksi.ksi_code = SI_QUEUE;
ksi.ksi_pid = td->td_proc->p_pid;
ksi.ksi_uid = td->td_ucred->cr_ruid;
- ksi.ksi_value.sival_ptr = uap->value;
+ ksi.ksi_value = *value;
error = pksignal(p, ksi.ksi_signo, &ksi);
}
PROC_UNLOCK(p);
Index: sys/sys/syscallsubr.h
===================================================================
--- sys/sys/syscallsubr.h
+++ sys/sys/syscallsubr.h
@@ -249,6 +249,8 @@
int kern_sigsuspend(struct thread *td, sigset_t mask);
int kern_sigtimedwait(struct thread *td, sigset_t waitset,
struct ksiginfo *ksi, struct timespec *timeout);
+int kern_sigqueue(struct thread *td, pid_t pid, int signum,
+ union sigval *value);
int kern_socket(struct thread *td, int domain, int type, int protocol);
int kern_statat(struct thread *td, int flag, int fd, char *path,
enum uio_seg pathseg, struct stat *sbp,

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