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GetMacosAlignedVersion() fails if sysctl is not setup 

`GetMacosAlignedVersion()` fails for ASan-ified launchd because the
sanitizer initialization code runs before `sysctl` has been setup by
launchd.  In this situation, `sysctl kern.osproductversion` returns a
non-empty string that does not match our expectations of a
well-formatted version string.

Retrieving the kernel version (via `sysctl kern.osrelease`) still works,
so we can use it to add a fallback for this corner case.

Differential Revision: https://reviews.llvm.org/D94190
This commit is contained in:
Julian Lettner 2021-01-06 12:41:40 -08:00
parent 86e604c4d6
commit 84de4faf4c
1 changed files with 31 additions and 12 deletions
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43
compiler-rt/lib/sanitizer_common/sanitizer_mac.cpp
View File

@ -620,6 +620,23 @@ constexpr u16 GetOSMajorKernelOffset() {
using VersStr = char[64];
static uptr ApproximateOSVersionViaKernelVersion(VersStr vers) {
u16 kernel_major = GetDarwinKernelVersion().major;
u16 offset = GetOSMajorKernelOffset();
CHECK_GE(kernel_major, offset);
u16 os_major = kernel_major - offset;
const char *format = "%d.0";
if (TARGET_OS_OSX) {
if (os_major >= 16) { // macOS 11+
os_major -= 5;
} else { // macOS 10.15 and below
format = "10.%d";
}
}
return internal_snprintf(vers, sizeof(VersStr), format, os_major);
}
static void GetOSVersion(VersStr vers) {
uptr len = sizeof(VersStr);
if (SANITIZER_IOSSIM) {
@ -633,17 +650,19 @@ static void GetOSVersion(VersStr vers) {
} else {
int res =
internal_sysctlbyname("kern.osproductversion", vers, &len, nullptr, 0);
if (res) {
// Fallback for XNU 17 (macOS 10.13) and below that do not provide the
// `kern.osproductversion` property.
u16 kernel_major = GetDarwinKernelVersion().major;
u16 offset = GetOSMajorKernelOffset();
CHECK_LE(kernel_major, 17);
CHECK_GE(kernel_major, offset);
u16 os_major = kernel_major - offset;
auto format = TARGET_OS_OSX ? "10.%d" : "%d.0";
len = internal_snprintf(vers, len, format, os_major);
// XNU 17 (macOS 10.13) and below do not provide the sysctl
// `kern.osproductversion` entry (res != 0).
bool no_os_version = res != 0;
// For launchd, sanitizer initialization runs before sysctl is setup
// (res == 0 && len != strlen(vers), vers is not a valid version). However,
// the kernel version `kern.osrelease` is available.
bool launchd = (res == 0 && internal_strlen(vers) < 3);
if (launchd) CHECK_EQ(internal_getpid(), 1);
if (no_os_version || launchd) {
len = ApproximateOSVersionViaKernelVersion(vers);
}
}
CHECK_LT(len, sizeof(VersStr));
@ -681,7 +700,7 @@ static void MapToMacos(u16 *major, u16 *minor) {
}
static MacosVersion GetMacosAlignedVersionInternal() {
VersStr vers;
VersStr vers = {};
GetOSVersion(vers);
u16 major, minor;
@ -707,7 +726,7 @@ MacosVersion GetMacosAlignedVersion() {
}
DarwinKernelVersion GetDarwinKernelVersion() {
VersStr vers;
VersStr vers = {};
uptr len = sizeof(VersStr);
int res = internal_sysctlbyname("kern.osrelease", vers, &len, nullptr, 0);
CHECK_EQ(res, 0);