strace/printsiginfo.c

/*
 * Copyright (c) 1991, 1992 Paul Kranenburg <pk@cs.few.eur.nl>
 * Copyright (c) 1993 Branko Lankester <branko@hacktic.nl>
 * Copyright (c) 1993-1996 Rick Sladkey <jrs@world.std.com>
 * Copyright (c) 1996-1999 Wichert Akkerman <wichert@cistron.nl>
 * Copyright (c) 2001 John Hughes <john@Calva.COM>
 * Copyright (c) 2013 Denys Vlasenko <vda.linux@googlemail.com>
 * Copyright (c) 2011-2015 Dmitry V. Levin <ldv@altlinux.org>
 * Copyright (c) 2015 Elvira Khabirova <lineprinter0@gmail.com>
 * Copyright (c) 2015-2018 The strace developers.
 * All rights reserved.
 *
 * SPDX-License-Identifier: LGPL-2.1-or-later
 */

#include "defs.h"

#include DEF_MPERS_TYPE(siginfo_t)

#include <signal.h>
#include <linux/audit.h>

#include MPERS_DEFS

#include "nr_prefix.c"

#ifndef IN_MPERS
#include "printsiginfo.h"
#endif

#include "xlat/audit_arch.h"
#include "xlat/sigbus_codes.h"
#include "xlat/sigchld_codes.h"
#include "xlat/sigfpe_codes.h"
#include "xlat/sigill_codes.h"
#include "xlat/siginfo_codes.h"
#include "xlat/sigpoll_codes.h"
#include "xlat/sigprof_codes.h"
#include "xlat/sigsegv_codes.h"
#include "xlat/sigsys_codes.h"
#include "xlat/sigtrap_codes.h"

#ifdef SIGEMT
# include "xlat/sigemt_codes.h"
#endif

#ifndef SI_FROMUSER
# define SI_FROMUSER(sip)	((sip)->si_code <= 0)
#endif

static void
printsigsource(const siginfo_t *sip)
{
	tprintf(", si_pid=%u, si_uid=%u",
		(unsigned int) sip->si_pid,
		(unsigned int) sip->si_uid);
}

static void
printsigval(const siginfo_t *sip)
{
	tprintf(", si_value={int=%d, ptr=", sip->si_int);
	printaddr(ptr_to_kulong(sip->si_ptr));
	tprints("}");
}

static void
print_si_code(int si_signo, unsigned int si_code)
{
	const char *code = xlookup(siginfo_codes, si_code);

	if (!code) {
		switch (si_signo) {
		case SIGTRAP:
			code = xlookup(sigtrap_codes, si_code);
			break;
		case SIGCHLD:
			code = xlookup(sigchld_codes, si_code);
			break;
		case SIGPOLL:
			code = xlookup(sigpoll_codes, si_code);
			break;
		case SIGPROF:
			code = xlookup(sigprof_codes, si_code);
			break;
		case SIGILL:
			code = xlookup(sigill_codes, si_code);
			break;
#ifdef SIGEMT
		case SIGEMT:
			code = xlookup(sigemt_codes, si_code);
			break;
#endif
		case SIGFPE:
			code = xlookup(sigfpe_codes, si_code);
			break;
		case SIGSEGV:
			code = xlookup(sigsegv_codes, si_code);
			break;
		case SIGBUS:
			code = xlookup(sigbus_codes, si_code);
			break;
		case SIGSYS:
			code = xlookup(sigsys_codes, si_code);
			break;
		}
	}

	print_xlat_ex(si_code, code, XLAT_STYLE_DEFAULT);
}

static void
print_si_info(const siginfo_t *sip)
{
	if (sip->si_errno) {
		tprints(", si_errno=");
		if ((unsigned) sip->si_errno < nerrnos
		    && errnoent[sip->si_errno])
			tprints(errnoent[sip->si_errno]);
		else
			tprintf("%d", sip->si_errno);
	}

	if (SI_FROMUSER(sip)) {
		switch (sip->si_code) {
		case SI_USER:
			printsigsource(sip);
			break;
		case SI_TKILL:
			printsigsource(sip);
			break;
#if defined HAVE_SIGINFO_T_SI_TIMERID && defined HAVE_SIGINFO_T_SI_OVERRUN
		case SI_TIMER:
			tprintf(", si_timerid=%#x, si_overrun=%d",
				sip->si_timerid, sip->si_overrun);
			printsigval(sip);
			break;
#endif
		default:
			printsigsource(sip);
			if (sip->si_ptr)
				printsigval(sip);
			break;
		}
	} else {
		switch (sip->si_signo) {
		case SIGCHLD:
			printsigsource(sip);
			tprints(", si_status=");
			if (sip->si_code == CLD_EXITED)
				tprintf("%d", sip->si_status);
			else
				printsignal(sip->si_status);
			tprintf(", si_utime=%llu, si_stime=%llu",
				zero_extend_signed_to_ull(sip->si_utime),
				zero_extend_signed_to_ull(sip->si_stime));
			break;
		case SIGILL: case SIGFPE:
		case SIGSEGV: case SIGBUS:
			tprints(", si_addr=");
			printaddr(ptr_to_kulong(sip->si_addr));
			break;
		case SIGPOLL:
			switch (sip->si_code) {
			case POLL_IN: case POLL_OUT: case POLL_MSG:
				tprintf(", si_band=%ld",
					(long) sip->si_band);
				break;
			}
			break;
#ifdef HAVE_SIGINFO_T_SI_SYSCALL
		case SIGSYS: {
			/*
			 * Note that we can safely use the personlity set in
			 * current_personality  here (and don't have to guess it
			 * based on X32_SYSCALL_BIT and si_arch, for example):
			 *  - The signal is delivered as a result of seccomp
			 *    filtering to the process executing forbidden
			 *    syscall.
			 *  - We have set the personality for the tracee during
			 *    the syscall entering.
			 *  - The current_personality is reliably switched in
			 *    the next_event routine, it is set to the
			 *    personality of the last call made (the one that
			 *    triggered the signal delivery).
			 *  - Looks like there are no other cases where SIGSYS
			 *    is delivered from the kernel so far.
			 */
			const char *scname = syscall_name(shuffle_scno(
				(unsigned) sip->si_syscall));

			tprints(", si_call_addr=");
			printaddr(ptr_to_kulong(sip->si_call_addr));
			tprints(", si_syscall=");
			if (scname)
				tprintf("%s%s",
					nr_prefix(sip->si_syscall), scname);
			else
				tprintf("%u", (unsigned) sip->si_syscall);
			tprints(", si_arch=");
			printxval(audit_arch, sip->si_arch, "AUDIT_ARCH_???");
			break;
		}
#endif
		default:
			if (sip->si_pid || sip->si_uid)
				printsigsource(sip);
			if (sip->si_ptr)
				printsigval(sip);
		}
	}
}

#ifdef IN_MPERS
static
#endif
void
printsiginfo(const siginfo_t *sip)
{
	if (sip->si_signo == 0) {
		tprints("{}");
		return;
	}
	tprints("{si_signo=");
	printsignal(sip->si_signo);

	tprints(", si_code=");
	print_si_code(sip->si_signo, sip->si_code);

#ifdef SI_NOINFO
	if (sip->si_code != SI_NOINFO)
#endif
		print_si_info(sip);

	tprints("}");
}

MPERS_PRINTER_DECL(void, printsiginfo_at,
		   struct tcb *const tcp, const kernel_ulong_t addr)
{
	siginfo_t si;

	if (!umove_or_printaddr(tcp, addr, &si))
		printsiginfo(&si);
}

static bool
print_siginfo_t(struct tcb *tcp, void *elem_buf, size_t elem_size, void *data)
{
	printsiginfo((const siginfo_t *) elem_buf);
	return true;
}

MPERS_PRINTER_DECL(void, print_siginfo_array, struct tcb *const tcp,
		   const kernel_ulong_t addr, const kernel_ulong_t len)
{
	siginfo_t si;

	print_array(tcp, addr, len, &si, sizeof(si),
		    tfetch_mem, print_siginfo_t, 0);
}