/*
* Copyright (c) 2016-2020 Apple Inc. All rights reserved.
*
* @APPLE_OSREFERENCE_LICENSE_HEADER_START@
*
* This file contains Original Code and/or Modifications of Original Code
* as defined in and that are subject to the Apple Public Source License
* Version 2.0 (the 'License'). You may not use this file except in
* compliance with the License. The rights granted to you under the License
* may not be used to create, or enable the creation or redistribution of,
* unlawful or unlicensed copies of an Apple operating system, or to
* circumvent, violate, or enable the circumvention or violation of, any
* terms of an Apple operating system software license agreement.
*
* Please obtain a copy of the License at
* http://www.opensource.apple.com/apsl/ and read it before using this file.
*
* The Original Code and all software distributed under the License are
* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
* Please see the License for the specific language governing rights and
* limitations under the License.
*
* @APPLE_OSREFERENCE_LICENSE_HEADER_END@
*/
#include <kern/backtrace.h>
#include <kern/kalloc.h>
#include <sys/errno.h>
#include <sys/sysctl.h>
#include <sys/systm.h>
#if DEVELOPMENT || DEBUG
/*
* Ignore -Wxnu-typed-allocators for this file, as it implements
* sysctls that are only available for DEVELOPMENT || DEBUG builds.
*/
__typed_allocators_ignore_push
#define MAX_BACKTRACE (128)
#define BACKTRACE_USER (0)
#define BACKTRACE_USER_RESUME (1)
static int backtrace_user_sysctl SYSCTL_HANDLER_ARGS;
#define BACKTRACE_KERN_TEST_PACK_UNPACK (0)
#define BACKTRACE_KERN_TEST_PACKED (1)
static int backtrace_kernel_sysctl SYSCTL_HANDLER_ARGS;
SYSCTL_NODE(_kern, OID_AUTO, backtrace, CTLFLAG_RW | CTLFLAG_LOCKED, 0,
"backtrace");
SYSCTL_PROC(_kern_backtrace, OID_AUTO, user,
CTLFLAG_RW | CTLFLAG_LOCKED, (void *)BACKTRACE_USER,
sizeof(uint64_t), backtrace_user_sysctl, "O",
"take user backtrace of current thread");
SYSCTL_PROC(_kern_backtrace, OID_AUTO, kernel_tests,
CTLFLAG_RW | CTLFLAG_LOCKED, (void *)BACKTRACE_USER,
sizeof(uint64_t), backtrace_kernel_sysctl, "O",
"take user backtrace of current thread");
static int
backtrace_kernel_sysctl SYSCTL_HANDLER_ARGS
{
unsigned int scenario = (unsigned int)req->newlen;
uintptr_t *bt = NULL;
uint8_t *packed_bt = NULL;
uintptr_t *unpacked_bt = NULL;
unsigned int bt_len = 0;
size_t bt_size = 0;
errno_t error = 0;
bt_len = 24;
bt_size = sizeof(bt[0]) * bt_len;
bt = kalloc_data(bt_size, Z_WAITOK | Z_ZERO);
packed_bt = kalloc_data(bt_size, Z_WAITOK | Z_ZERO);
unpacked_bt = kalloc_data(bt_size, Z_WAITOK | Z_ZERO);
if (!bt || !packed_bt || !unpacked_bt) {
error = ENOBUFS;
goto out;
}
backtrace_info_t info = BTI_NONE;
unsigned int len = backtrace(bt, bt_len, NULL, &info);
backtrace_info_t packed_info = BTI_NONE;
size_t packed_size = 0;
if (scenario == BACKTRACE_KERN_TEST_PACK_UNPACK) {
packed_size = backtrace_pack(BTP_KERN_OFFSET_32, packed_bt, bt_size,
bt, len);
} else {
packed_size = backtrace_packed(BTP_KERN_OFFSET_32, packed_bt, bt_size,
NULL, &packed_info);
}
unsigned int unpacked_len = backtrace_unpack(BTP_KERN_OFFSET_32,
unpacked_bt, bt_len, packed_bt, packed_size);
if (unpacked_len != len) {
printf("backtrace_tests: length %u != %u unpacked\n", len,
unpacked_len);
error = ERANGE;
goto out;
}
for (unsigned int i = 0; i < len; i++) {
if (unpacked_bt[i] != bt[i]) {
printf("backtrace_tests: bad address %u: 0x%lx != 0x%lx unpacked",
i, bt[i], unpacked_bt[i]);
error = EINVAL;
}
}
out:
if (bt) {
kfree_data(bt, bt_size);
}
if (packed_bt) {
kfree_data(packed_bt, bt_size);
}
if (unpacked_bt) {
kfree_data(unpacked_bt, bt_size);
}
return error;
}
static int
backtrace_user_sysctl SYSCTL_HANDLER_ARGS
{
#pragma unused(oidp, arg1, arg2)
unsigned int scenario = (unsigned int)req->newlen;
uintptr_t *bt = NULL;
unsigned int bt_len = 0, bt_filled = 0, bt_space = 0;
size_t bt_size = 0;
errno_t error = 0;
bool user_scenario = scenario == BACKTRACE_USER;
bool resume_scenario = scenario == BACKTRACE_USER_RESUME;
if (!user_scenario && !resume_scenario) {
return ENOTSUP;
}
if (req->oldptr == USER_ADDR_NULL || req->oldlen == 0) {
return EFAULT;
}
bt_len = req->oldlen > MAX_BACKTRACE ? MAX_BACKTRACE :
(unsigned int)req->oldlen;
bt_size = sizeof(bt[0]) * bt_len;
bt = kalloc_data(bt_size, Z_WAITOK | Z_ZERO);
if (!bt) {
return ENOBUFS;
}
bt_space = resume_scenario ? bt_len / 2 : bt_len;
struct backtrace_user_info btinfo = BTUINFO_INIT;
bt_filled = backtrace_user(bt, bt_space, NULL, &btinfo);
error = btinfo.btui_error;
if (error != 0) {
goto out;
}
if (resume_scenario) {
if (!(btinfo.btui_info & BTI_TRUNCATED)) {
error = ENOSPC;
goto out;
}
struct backtrace_control ctl = {
.btc_frame_addr = btinfo.btui_next_frame_addr,
};
btinfo = BTUINFO_INIT;
unsigned int bt_more = backtrace_user(bt + bt_filled, bt_space, &ctl,
&btinfo);
error = btinfo.btui_error;
if (error != 0) {
goto out;
}
bt_filled += bt_more;
}
bt_filled = min(bt_filled, bt_len);
if (btinfo.btui_async_frame_addr != 0 &&
btinfo.btui_async_start_index != 0) {
// Put the async call stack inline after the real call stack.
unsigned int start_index = btinfo.btui_async_start_index;
uintptr_t frame_addr = btinfo.btui_async_frame_addr;
unsigned int bt_left = bt_len - start_index;
struct backtrace_control ctl = { .btc_frame_addr = frame_addr, };
btinfo = BTUINFO_INIT;
unsigned int async_filled = backtrace_user(bt + start_index, bt_left,
&ctl, &btinfo);
error = btinfo.btui_error;
if (error != 0) {
goto out;
}
bt_filled = min(start_index + async_filled, bt_len);
}
error = copyout(bt, req->oldptr, sizeof(bt[0]) * bt_filled);
if (error) {
goto out;
}
req->oldidx = bt_filled;
out:
kfree_data(bt, bt_size);
return error;
}
__typed_allocators_ignore_pop
#endif /* DEVELOPMENT || DEBUG */