target_sigemptyset: resets a set to having no bits set
qemu_sigorset:      computes the or of two sets
target_sigaddset:   adds a signal to a set
target_sigismember: returns true when signal is a member
host_to_target_sigset_internal: convert host sigset to target
host_to_target_sigset: convert host sigset to target
target_to_host_sigset_internal: convert target sigset to host
target_to_host_sigset: convert target sigset to host

Signed-off-by: Stacey Son <sson@FreeBSD.org>
Signed-off-by: Kyle Evans <kevans@freebsd.org>
Signed-off-by: Warner Losh <imp@bsdimp.com>
---
 bsd-user/qemu.h   |  3 ++
 bsd-user/signal.c | 89 +++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 92 insertions(+)

diff --git a/bsd-user/qemu.h b/bsd-user/qemu.h
index e12617f5d69..e8c417c7c33 100644
--- a/bsd-user/qemu.h
+++ b/bsd-user/qemu.h
@@ -223,7 +223,10 @@ void queue_signal(CPUArchState *env, int sig, target_siginfo_t *info);
 abi_long do_sigaltstack(abi_ulong uss_addr, abi_ulong uoss_addr, abi_ulong sp);
 int target_to_host_signal(int sig);
 int host_to_target_signal(int sig);
+void host_to_target_sigset(target_sigset_t *d, const sigset_t *s);
+void target_to_host_sigset(sigset_t *d, const target_sigset_t *s);
 void QEMU_NORETURN force_sig(int target_sig);
+int qemu_sigorset(sigset_t *dest, const sigset_t *left, const sigset_t *right);
 
 /* mmap.c */
 int target_mprotect(abi_ulong start, abi_ulong len, int prot);
diff --git a/bsd-user/signal.c b/bsd-user/signal.c
index 93c3b3c5033..8dadc9a39a7 100644
--- a/bsd-user/signal.c
+++ b/bsd-user/signal.c
@@ -32,6 +32,9 @@
 
 static struct target_sigaction sigact_table[TARGET_NSIG];
 static void host_signal_handler(int host_sig, siginfo_t *info, void *puc);
+static void target_to_host_sigset_internal(sigset_t *d,
+        const target_sigset_t *s);
+
 
 int host_to_target_signal(int sig)
 {
@@ -43,6 +46,44 @@ int target_to_host_signal(int sig)
     return sig;
 }
 
+static inline void target_sigemptyset(target_sigset_t *set)
+{
+    memset(set, 0, sizeof(*set));
+}
+
+#include <signal.h>
+
+int
+qemu_sigorset(sigset_t *dest, const sigset_t *left, const sigset_t *right)
+{
+    sigset_t work;
+    int i;
+
+    sigemptyset(&work);
+    for (i = 1; i < NSIG; ++i) {
+        if (sigismember(left, i) || sigismember(right, i)) {
+            sigaddset(&work, i);
+        }
+    }
+
+    *dest = work;
+    return 0;
+}
+
+static inline void target_sigaddset(target_sigset_t *set, int signum)
+{
+    signum--;
+    uint32_t mask = (uint32_t)1 << (signum % TARGET_NSIG_BPW);
+    set->__bits[signum / TARGET_NSIG_BPW] |= mask;
+}
+
+static inline int target_sigismember(const target_sigset_t *set, int signum)
+{
+    signum--;
+    abi_ulong mask = (abi_ulong)1 << (signum % TARGET_NSIG_BPW);
+    return (set->__bits[signum / TARGET_NSIG_BPW] & mask) != 0;
+}
+
 /* Adjust the signal context to rewind out of safe-syscall if we're in it */
 static inline void rewind_if_in_safe_syscall(void *puc)
 {
@@ -55,6 +96,54 @@ static inline void rewind_if_in_safe_syscall(void *puc)
     }
 }
 
+static void host_to_target_sigset_internal(target_sigset_t *d,
+        const sigset_t *s)
+{
+    int i;
+
+    target_sigemptyset(d);
+    for (i = 1; i <= TARGET_NSIG; i++) {
+        if (sigismember(s, i)) {
+            target_sigaddset(d, host_to_target_signal(i));
+        }
+    }
+}
+
+void host_to_target_sigset(target_sigset_t *d, const sigset_t *s)
+{
+    target_sigset_t d1;
+    int i;
+
+    host_to_target_sigset_internal(&d1, s);
+    for (i = 0; i < TARGET_NSIG_WORDS; i++) {
+        d->__bits[i] = tswap32(d1.__bits[i]);
+    }
+}
+
+static void target_to_host_sigset_internal(sigset_t *d,
+        const target_sigset_t *s)
+{
+    int i;
+
+    sigemptyset(d);
+    for (i = 1; i <= TARGET_NSIG; i++) {
+        if (target_sigismember(s, i)) {
+            sigaddset(d, target_to_host_signal(i));
+        }
+    }
+}
+
+void target_to_host_sigset(sigset_t *d, const target_sigset_t *s)
+{
+    target_sigset_t s1;
+    int i;
+
+    for (i = 0; i < TARGET_NSIG_WORDS; i++) {
+        s1.__bits[i] = tswap32(s->__bits[i]);
+    }
+    target_to_host_sigset_internal(d, &s1);
+}
+
 /* Siginfo conversion. */
 static inline void host_to_target_siginfo_noswap(target_siginfo_t *tinfo,
         const siginfo_t *info)
-- 
2.33.1

On Sun, 9 Jan 2022 at 16:53, Warner Losh <imp@bsdimp.com> wrote:
>
> target_sigemptyset: resets a set to having no bits set
> qemu_sigorset:      computes the or of two sets
> target_sigaddset:   adds a signal to a set
> target_sigismember: returns true when signal is a member
> host_to_target_sigset_internal: convert host sigset to target
> host_to_target_sigset: convert host sigset to target
> target_to_host_sigset_internal: convert target sigset to host
> target_to_host_sigset: convert target sigset to host
>
> Signed-off-by: Stacey Son <sson@FreeBSD.org>
> Signed-off-by: Kyle Evans <kevans@freebsd.org>
> Signed-off-by: Warner Losh <imp@bsdimp.com>
> ---
>  bsd-user/qemu.h   |  3 ++
>  bsd-user/signal.c | 89 +++++++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 92 insertions(+)
>
> diff --git a/bsd-user/qemu.h b/bsd-user/qemu.h
> index e12617f5d69..e8c417c7c33 100644
> --- a/bsd-user/qemu.h
> +++ b/bsd-user/qemu.h
> @@ -223,7 +223,10 @@ void queue_signal(CPUArchState *env, int sig, target_siginfo_t *info);
>  abi_long do_sigaltstack(abi_ulong uss_addr, abi_ulong uoss_addr, abi_ulong sp);
>  int target_to_host_signal(int sig);
>  int host_to_target_signal(int sig);
> +void host_to_target_sigset(target_sigset_t *d, const sigset_t *s);
> +void target_to_host_sigset(sigset_t *d, const target_sigset_t *s);
>  void QEMU_NORETURN force_sig(int target_sig);
> +int qemu_sigorset(sigset_t *dest, const sigset_t *left, const sigset_t *right);
>
>  /* mmap.c */
>  int target_mprotect(abi_ulong start, abi_ulong len, int prot);
> diff --git a/bsd-user/signal.c b/bsd-user/signal.c
> index 93c3b3c5033..8dadc9a39a7 100644
> --- a/bsd-user/signal.c
> +++ b/bsd-user/signal.c
> @@ -32,6 +32,9 @@
>
>  static struct target_sigaction sigact_table[TARGET_NSIG];
>  static void host_signal_handler(int host_sig, siginfo_t *info, void *puc);
> +static void target_to_host_sigset_internal(sigset_t *d,
> +        const target_sigset_t *s);
> +
>
>  int host_to_target_signal(int sig)
>  {
> @@ -43,6 +46,44 @@ int target_to_host_signal(int sig)
>      return sig;
>  }
>
> +static inline void target_sigemptyset(target_sigset_t *set)
> +{
> +    memset(set, 0, sizeof(*set));
> +}
> +
> +#include <signal.h>

Don't include system headers halfway through the file like this,
please : put the #include at the top of the file with the others.

> +
> +int
> +qemu_sigorset(sigset_t *dest, const sigset_t *left, const sigset_t *right)
> +{
> +    sigset_t work;
> +    int i;
> +
> +    sigemptyset(&work);
> +    for (i = 1; i < NSIG; ++i) {
> +        if (sigismember(left, i) || sigismember(right, i)) {
> +            sigaddset(&work, i);
> +        }
> +    }
> +
> +    *dest = work;
> +    return 0;
> +}

FreeBSD's manpage says it has a native sigorset() --
https://www.freebsd.org/cgi/man.cgi?query=sigemptyset&sektion=3&apropos=0&manpath=freebsd
can you just use that ?

> +
> +static inline void target_sigaddset(target_sigset_t *set, int signum)
> +{
> +    signum--;
> +    uint32_t mask = (uint32_t)1 << (signum % TARGET_NSIG_BPW);
> +    set->__bits[signum / TARGET_NSIG_BPW] |= mask;
> +}
> +
> +static inline int target_sigismember(const target_sigset_t *set, int signum)
> +{
> +    signum--;
> +    abi_ulong mask = (abi_ulong)1 << (signum % TARGET_NSIG_BPW);
> +    return (set->__bits[signum / TARGET_NSIG_BPW] & mask) != 0;
> +}
> +
>  /* Adjust the signal context to rewind out of safe-syscall if we're in it */
>  static inline void rewind_if_in_safe_syscall(void *puc)
>  {
> @@ -55,6 +96,54 @@ static inline void rewind_if_in_safe_syscall(void *puc)
>      }
>  }
>
> +static void host_to_target_sigset_internal(target_sigset_t *d,
> +        const sigset_t *s)
> +{
> +    int i;
> +
> +    target_sigemptyset(d);
> +    for (i = 1; i <= TARGET_NSIG; i++) {

i here is iterating through host signal numbers, not target
numbers, so TARGET_NSIG isn't the right upper bound.
On Linux we iterate from 1 to _NSIG-1; on BSD I think
you may want (i = 0; i < NSIG; i++), but you should check that.

> +        if (sigismember(s, i)) {
> +            target_sigaddset(d, host_to_target_signal(i));
> +        }
> +    }
> +}

These functions are a little odd when you compare them to their
linux-user equivalents, because they're both written
with a sort of abstraction between host and target signal
numbers (they call host_to_target_signal() and
target_to_host_signal()) but also written with baked-in
assumptions that the mapping is basically 1:1 (they don't
have the code that handles the possibility that the
target signal isn't representable as a host signal or
vice-versa). But assuming the BSDs don't change their
signal numbering across architectures, this is fine.

thanks
-- PMM

On Fri, Jan 14, 2022 at 4:14 AM Peter Maydell <peter.maydell@linaro.org>
wrote:

> On Sun, 9 Jan 2022 at 16:53, Warner Losh <imp@bsdimp.com> wrote:
> >
> > target_sigemptyset: resets a set to having no bits set
> > qemu_sigorset:      computes the or of two sets
> > target_sigaddset:   adds a signal to a set
> > target_sigismember: returns true when signal is a member
> > host_to_target_sigset_internal: convert host sigset to target
> > host_to_target_sigset: convert host sigset to target
> > target_to_host_sigset_internal: convert target sigset to host
> > target_to_host_sigset: convert target sigset to host
> >
> > Signed-off-by: Stacey Son <sson@FreeBSD.org>
> > Signed-off-by: Kyle Evans <kevans@freebsd.org>
> > Signed-off-by: Warner Losh <imp@bsdimp.com>
> > ---
> >  bsd-user/qemu.h   |  3 ++
> >  bsd-user/signal.c | 89 +++++++++++++++++++++++++++++++++++++++++++++++
> >  2 files changed, 92 insertions(+)
> >
> > diff --git a/bsd-user/qemu.h b/bsd-user/qemu.h
> > index e12617f5d69..e8c417c7c33 100644
> > --- a/bsd-user/qemu.h
> > +++ b/bsd-user/qemu.h
> > @@ -223,7 +223,10 @@ void queue_signal(CPUArchState *env, int sig,
> target_siginfo_t *info);
> >  abi_long do_sigaltstack(abi_ulong uss_addr, abi_ulong uoss_addr,
> abi_ulong sp);
> >  int target_to_host_signal(int sig);
> >  int host_to_target_signal(int sig);
> > +void host_to_target_sigset(target_sigset_t *d, const sigset_t *s);
> > +void target_to_host_sigset(sigset_t *d, const target_sigset_t *s);
> >  void QEMU_NORETURN force_sig(int target_sig);
> > +int qemu_sigorset(sigset_t *dest, const sigset_t *left, const sigset_t
> *right);
> >
> >  /* mmap.c */
> >  int target_mprotect(abi_ulong start, abi_ulong len, int prot);
> > diff --git a/bsd-user/signal.c b/bsd-user/signal.c
> > index 93c3b3c5033..8dadc9a39a7 100644
> > --- a/bsd-user/signal.c
> > +++ b/bsd-user/signal.c
> > @@ -32,6 +32,9 @@
> >
> >  static struct target_sigaction sigact_table[TARGET_NSIG];
> >  static void host_signal_handler(int host_sig, siginfo_t *info, void
> *puc);
> > +static void target_to_host_sigset_internal(sigset_t *d,
> > +        const target_sigset_t *s);
> > +
> >
> >  int host_to_target_signal(int sig)
> >  {
> > @@ -43,6 +46,44 @@ int target_to_host_signal(int sig)
> >      return sig;
> >  }
> >
> > +static inline void target_sigemptyset(target_sigset_t *set)
> > +{
> > +    memset(set, 0, sizeof(*set));
> > +}
> > +
> > +#include <signal.h>
>
> Don't include system headers halfway through the file like this,
> please : put the #include at the top of the file with the others.
>

Yea, this isn't even needed, so I just removed it.


> > +
> > +int
> > +qemu_sigorset(sigset_t *dest, const sigset_t *left, const sigset_t
> *right)
> > +{
> > +    sigset_t work;
> > +    int i;
> > +
> > +    sigemptyset(&work);
> > +    for (i = 1; i < NSIG; ++i) {
> > +        if (sigismember(left, i) || sigismember(right, i)) {
> > +            sigaddset(&work, i);
> > +        }
> > +    }
> > +
> > +    *dest = work;
> > +    return 0;
> > +}
>
> FreeBSD's manpage says it has a native sigorset() --
>
> https://www.freebsd.org/cgi/man.cgi?query=sigemptyset&sektion=3&apropos=0&manpath=freebsd
> can you just use that ?
>

Yes.


> > +
> > +static inline void target_sigaddset(target_sigset_t *set, int signum)
> > +{
> > +    signum--;
> > +    uint32_t mask = (uint32_t)1 << (signum % TARGET_NSIG_BPW);
> > +    set->__bits[signum / TARGET_NSIG_BPW] |= mask;
> > +}
> > +
> > +static inline int target_sigismember(const target_sigset_t *set, int
> signum)
> > +{
> > +    signum--;
> > +    abi_ulong mask = (abi_ulong)1 << (signum % TARGET_NSIG_BPW);
> > +    return (set->__bits[signum / TARGET_NSIG_BPW] & mask) != 0;
> > +}
> > +
> >  /* Adjust the signal context to rewind out of safe-syscall if we're in
> it */
> >  static inline void rewind_if_in_safe_syscall(void *puc)
> >  {
> > @@ -55,6 +96,54 @@ static inline void rewind_if_in_safe_syscall(void
> *puc)
> >      }
> >  }
> >
> > +static void host_to_target_sigset_internal(target_sigset_t *d,
> > +        const sigset_t *s)
> > +{
> > +    int i;
> > +
> > +    target_sigemptyset(d);
> > +    for (i = 1; i <= TARGET_NSIG; i++) {
>
> i here is iterating through host signal numbers, not target
> numbers, so TARGET_NSIG isn't the right upper bound.
> On Linux we iterate from 1 to _NSIG-1; on BSD I think
> you may want (i = 0; i < NSIG; i++), but you should check that.
>

You're correct. The values are the same, but logically NSIG is more correct.


> > +        if (sigismember(s, i)) {
> > +            target_sigaddset(d, host_to_target_signal(i));
> > +        }
> > +    }
> > +}
>
> These functions are a little odd when you compare them to their
> linux-user equivalents, because they're both written
> with a sort of abstraction between host and target signal
> numbers (they call host_to_target_signal() and
> target_to_host_signal()) but also written with baked-in
> assumptions that the mapping is basically 1:1 (they don't
> have the code that handles the possibility that the
> target signal isn't representable as a host signal or
> vice-versa). But assuming the BSDs don't change their
> signal numbering across architectures, this is fine.
>

I can assume that, at least for now, so I've just added a comment
about that.

Warner

On Sat, Jan 22, 2022 at 10:44 AM Warner Losh <imp@bsdimp.com> wrote:
>
>
>
> On Fri, Jan 14, 2022 at 4:14 AM Peter Maydell <peter.maydell@linaro.org> wrote:
>>
>> On Sun, 9 Jan 2022 at 16:53, Warner Losh <imp@bsdimp.com> wrote:
>> >
>> > target_sigemptyset: resets a set to having no bits set
>> > qemu_sigorset:      computes the or of two sets
>> > target_sigaddset:   adds a signal to a set
>> > target_sigismember: returns true when signal is a member
>> > host_to_target_sigset_internal: convert host sigset to target
>> > host_to_target_sigset: convert host sigset to target
>> > target_to_host_sigset_internal: convert target sigset to host
>> > target_to_host_sigset: convert target sigset to host
>> >
>> > Signed-off-by: Stacey Son <sson@FreeBSD.org>
>> > Signed-off-by: Kyle Evans <kevans@freebsd.org>
>> > Signed-off-by: Warner Losh <imp@bsdimp.com>
>> > ---
>> >  bsd-user/qemu.h   |  3 ++
>> >  bsd-user/signal.c | 89 +++++++++++++++++++++++++++++++++++++++++++++++
>> >  2 files changed, 92 insertions(+)
>> >
>> > diff --git a/bsd-user/qemu.h b/bsd-user/qemu.h
>> > index e12617f5d69..e8c417c7c33 100644
>> > --- a/bsd-user/qemu.h
>> > +++ b/bsd-user/qemu.h
>> > @@ -223,7 +223,10 @@ void queue_signal(CPUArchState *env, int sig, target_siginfo_t *info);
>> >  abi_long do_sigaltstack(abi_ulong uss_addr, abi_ulong uoss_addr, abi_ulong sp);
>> >  int target_to_host_signal(int sig);
>> >  int host_to_target_signal(int sig);
>> > +void host_to_target_sigset(target_sigset_t *d, const sigset_t *s);
>> > +void target_to_host_sigset(sigset_t *d, const target_sigset_t *s);
>> >  void QEMU_NORETURN force_sig(int target_sig);
>> > +int qemu_sigorset(sigset_t *dest, const sigset_t *left, const sigset_t *right);
>> >
>> >  /* mmap.c */
>> >  int target_mprotect(abi_ulong start, abi_ulong len, int prot);
>> > diff --git a/bsd-user/signal.c b/bsd-user/signal.c
>> > index 93c3b3c5033..8dadc9a39a7 100644
>> > --- a/bsd-user/signal.c
>> > +++ b/bsd-user/signal.c
>> > @@ -32,6 +32,9 @@
>> >
>> >  static struct target_sigaction sigact_table[TARGET_NSIG];
>> >  static void host_signal_handler(int host_sig, siginfo_t *info, void *puc);
>> > +static void target_to_host_sigset_internal(sigset_t *d,
>> > +        const target_sigset_t *s);
>> > +
>> >
>> >  int host_to_target_signal(int sig)
>> >  {
>> > @@ -43,6 +46,44 @@ int target_to_host_signal(int sig)
>> >      return sig;
>> >  }
>> >
>> > +static inline void target_sigemptyset(target_sigset_t *set)
>> > +{
>> > +    memset(set, 0, sizeof(*set));
>> > +}
>> > +
>> > +#include <signal.h>
>>
>> Don't include system headers halfway through the file like this,
>> please : put the #include at the top of the file with the others.
>
>
> Yea, this isn't even needed, so I just removed it.
>
>>
>> > +
>> > +int
>> > +qemu_sigorset(sigset_t *dest, const sigset_t *left, const sigset_t *right)
>> > +{
>> > +    sigset_t work;
>> > +    int i;
>> > +
>> > +    sigemptyset(&work);
>> > +    for (i = 1; i < NSIG; ++i) {
>> > +        if (sigismember(left, i) || sigismember(right, i)) {
>> > +            sigaddset(&work, i);
>> > +        }
>> > +    }
>> > +
>> > +    *dest = work;
>> > +    return 0;
>> > +}
>>
>> FreeBSD's manpage says it has a native sigorset() --
>> https://www.freebsd.org/cgi/man.cgi?query=sigemptyset&sektion=3&apropos=0&manpath=freebsd
>> can you just use that ?
>
>
> Yes.
>

For some added context, I added sigorset() to libc after 11.3/12.1 in
response to bsd-user using it, then forgot to remove the transition
aide after they went EoL.

Thanks,

Kyle Evans