execve.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) 2007 Roland McGrath <roland@redhat.com>
 * Copyright (c) 2011-2012 Denys Vlasenko <vda.linux@googlemail.com>
 * Copyright (c) 2010-2015 Dmitry V. Levin <ldv@altlinux.org>
 * Copyright (c) 2014-2019 The strace developers.
 * All rights reserved.
 *
 * SPDX-License-Identifier: LGPL-2.1-or-later
 */

#include "defs.h"

static void
printargv(struct tcb *const tcp, kernel_ulong_t addr)
{
	if (!addr || !verbose(tcp)) {
		printaddr(addr);
		return;
	}

	const char *const start_sep = "[";
	const char *sep = start_sep;
	const unsigned int wordsize = current_wordsize;
	unsigned int n;

	for (n = 0; addr; sep = ", ", addr += wordsize, ++n) {
		union {
			unsigned int p32;
			kernel_ulong_t p64;
			char data[sizeof(kernel_ulong_t)];
		} cp;

		if (umoven(tcp, addr, wordsize, cp.data)) {
			if (sep == start_sep)
				printaddr(addr);
			else {
				tprints(", ...");
				printaddr_comment(addr);
				tprints("]");
			}
			return;
		}
		if (!(wordsize < sizeof(cp.p64) ? cp.p32 : cp.p64)) {
			if (sep == start_sep)
				tprints(start_sep);
			break;
		}
		if (abbrev(tcp) && n >= max_strlen) {
			tprintf("%s...", sep);
			break;
		}
		tprints(sep);
		printstr(tcp, wordsize < sizeof(cp.p64) ? cp.p32 : cp.p64);
	}
	tprints("]");
}

static void
printargc(struct tcb *const tcp, kernel_ulong_t addr)
{
	printaddr(addr);

	if (!addr || !verbose(tcp))
		return;

	bool unterminated = false;
	unsigned int count = 0;
	char *cp = NULL;

	for (; addr; addr += current_wordsize, ++count) {
		if (umoven(tcp, addr, current_wordsize, &cp)) {
			if (!count)
				return;

			unterminated = true;
			break;
		}
		if (!cp)
			break;
	}
	tprintf_comment("%u var%s%s",
		count, count == 1 ? "" : "s",
		unterminated ? ", unterminated" : "");
}

static void
decode_execve(struct tcb *tcp, const unsigned int index)
{
	printpath(tcp, tcp->u_arg[index + 0]);
	tprints(", ");

	printargv(tcp, tcp->u_arg[index + 1]);
	tprints(", ");

	(abbrev(tcp) ? printargc : printargv) (tcp, tcp->u_arg[index + 2]);
}

SYS_FUNC(execve)
{
	decode_execve(tcp, 0);

	return RVAL_DECODED;
}

SYS_FUNC(execveat)
{
	print_dirfd(tcp, tcp->u_arg[0]);
	tprints(", ");
	decode_execve(tcp, 1);
	tprints(", ");
	printflags(at_flags, tcp->u_arg[4], "AT_???");

	return RVAL_DECODED;
}

#if defined(SPARC) || defined(SPARC64)
SYS_FUNC(execv)
{
	printpath(tcp, tcp->u_arg[0]);
	tprints(", ");
	printargv(tcp, tcp->u_arg[1]);

	return RVAL_DECODED;
}
#endif /* SPARC || SPARC64 */