tools/time.c
author Norm Jacobs <Norm.Jacobs@Oracle.COM>
Wed, 23 Feb 2011 10:37:11 -0800
changeset 99 c15c9099bb44
parent 16 33aaaec59991
child 998 3f6ed23e8aae
permissions -rw-r--r--
6841644 OpenSolaris Python should support gdbm 6991811 Migrate Mercurial (Hg) to Python 2.6 7009592 PyOpenSSL should be updated from 0.8 to 0.11 7016735 move mercurial from sfw to userland 7018363 Userland LD_OPTIONS should include non-executable data mapfiles as well 7019410 python 2.6 should move to userland 7020772 userland build should provide more macros for common flags 7021204 userland runpath checking should relax slightly.
/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 *
 * Copyright (c) 2010, Oracle and/or it's affiliates.  All rights reserved.
 */

/*
 * This compiles to a module that can be preloaded during a build.  If this
 * is preloaded, it interposes on time(2), gettimeofday(3C), and
 * clock_gethrtime(3C) and returns a constant number of seconds since epoch
 * when the execname matches one of the desired "programs" and TIME_CONSTANT
 * contains an integer value to be returned.
 */

#include <stdlib.h>
#include <ucontext.h>
#include <dlfcn.h>
#include <strings.h>
#include <time.h>

/* The list of programs that we want to use a constant time. */
static char *programs[] = { "autogen", "bash", "cpp", "cc1", "date", "doxygen",
	"erl", "javadoc", "ksh", "ksh93", "ld", "perl", "perl5.8.4", "perl5.10",
	"ruby", "sh", NULL };

static int
stack_info(uintptr_t pc, int signo, void *arg)
{
	Dl_info info;
	void *sym;

	if (dladdr1((void *)pc, &info, &sym, RTLD_DL_SYMENT) != NULL) {
		if (strstr(info.dli_fname, ".so") == NULL)
			*(char **)arg = (char *)info.dli_fname;
	}

	return (0);
}

static char *
my_execname()
{
	static char *execname;

	if (execname == NULL) {
		ucontext_t ctx;

		if (getcontext(&ctx) == 0)
			walkcontext(&ctx, stack_info, &execname);

		if (execname != NULL) {
			char *s = strrchr(execname, '/');

			if (s != NULL)
				execname = ++s;
		}
	}

	return (execname);
}

static time_t
time_constant()
{
	char *execname = my_execname();
	time_t result = -1;

	if (execname != NULL) {
		int i;

		for (i = 0; programs[i] != NULL; i++)
			if (strcmp(execname, programs[i]) == 0) {
				static char *time_string;

				if (time_string == NULL)
					time_string = getenv("TIME_CONSTANT");

				if (time_string != NULL)
					result = atoll(time_string);

				break;
			}
	}

	return (result);
}

time_t
time(time_t *ptr)
{
	time_t result = time_constant();

	if (result == (time_t)-1) {
		static time_t (*fptr)(time_t *);

		if (fptr == NULL)
			fptr = (time_t (*)(time_t *))dlsym(RTLD_NEXT, "time");

		result = (fptr)(ptr);
	} else if (ptr != NULL)
			*ptr = result;

	return (result);
}

int
gettimeofday(struct timeval *tp, void *tzp)
{
	static int (*fptr)(struct timeval *, void *);
	int result = -1;

	if (fptr == NULL)
		fptr = (int (*)(struct timeval *, void *))dlsym(RTLD_NEXT,
				"gettimeofday");

	if ((result = (fptr)(tp, tzp)) == 0) {
		time_t curtime = time_constant();

		if (curtime != (time_t)-1)
			tp->tv_sec = curtime;
	}

	return (result);
}

int
clock_gettime(clockid_t clock_id, struct timespec *tp)
{
	static int (*fptr)(clockid_t, struct timespec *);
	int result = -1;

	if (fptr == NULL)
		fptr = (int (*)(clockid_t, struct timespec *))dlsym(RTLD_NEXT,
				"clock_gettime");

	if ((result = (fptr)(clock_id, tp)) == 0) {
		time_t curtime = time_constant();

		if (curtime != (time_t)-1)
			tp->tv_sec = curtime;
	}

	return (result);
}