printsiginfo: decode si_pkey field

This adds decoding of si_pkey field  which is set on SIGSEGV in case
of memory access violation on some modern CPUs (these have pku flag in
/proc/cpuinfo).

* NEWS: Mention this change.
* configure.ac (AC_CHECK_MEMBERS): Check for siginfo_t.si_pkey
* src/printsiginfo.c: decode si_pkey field.

NEWS

@@ -12,6 +12,7 @@ Noteworthy changes in release ?.?? (????-??-??)
   * Implemented decoding of PR_SET_VMA operation of prctl syscall.
   * Updated lists of FAN_*, IORING_*, IOSQE_*, KVM_*, MODULE_INIT_*, TCA_ACT_*,
     and *_MAGIC constants.
+  * Add decoding of si_pkey field in siginfo struct
 
 * Bug fixes
 

configure.ac

@@ -423,7 +423,8 @@ AC_CHECK_MEMBERS([struct utsname.domainname],,, [#include <sys/utsname.h>])
 AC_CHECK_MEMBERS(m4_normalize([
 	siginfo_t.si_syscall,
 	siginfo_t.si_timerid,
-	siginfo_t.si_overrun
+	siginfo_t.si_overrun,
+	siginfo_t.si_pkey
 ]),,, [#include <signal.h>])
 
 AC_CHECK_HEADERS(m4_normalize([

src/printsiginfo.c

@@ -165,6 +165,12 @@ print_si_info(struct tcb *tcp, const siginfo_t *sip)
 		case SIGSEGV: case SIGBUS:
 			tprint_struct_next();
 			PRINT_FIELD_PTR(*sip, si_addr);
+#ifdef HAVE_SIGINFO_T_SI_PKEY
+			if (sip->si_signo == SIGSEGV && sip->si_code == SEGV_PKUERR) {
+				tprint_struct_next();
+				PRINT_FIELD_D(*sip, si_pkey);
+			}
+#endif
 			break;
 		case SIGPOLL:
 			switch (sip->si_code) {