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Implement crash reporting for AARCH64

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The ShowCrashReports() feature for aarch64 should work even better than
the x86 crash reports. Thanks to the benefit of hindsight these reports
should be rock solid reliable and beautiful to read.

This change also improves the syscall polyfills for aarch64. Some of the
sys_foo() functions have been removed, usually because they're legacy or
downright footguns not worth building.
This commit is contained in:
Justine Tunney 2023-05-12 05:47:54 -07:00
parent 285e8a2348
commit 1f2a5a8fc1
No known key found for this signature in database
GPG key ID: BE714B4575D6E328
42 changed files with 540 additions and 247 deletions
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130
libc/log/showcrashreports.c
View file

@ -25,6 +25,8 @@
#include "libc/log/internal.h"
#include "libc/log/log.h"
#include "libc/macros.internal.h"
#include "libc/mem/mem.h"
#include "libc/runtime/runtime.h"
#include "libc/runtime/stack.h"
#include "libc/runtime/symbols.internal.h"
#include "libc/str/str.h"
@ -34,8 +36,6 @@
#include "libc/sysv/consts/sig.h"
#include "libc/sysv/consts/ss.h"
#ifdef __x86_64__
STATIC_YOINK("zipos"); // for symtab
STATIC_YOINK("__die"); // for backtracing
STATIC_YOINK("ShowBacktrace"); // for backtracing
@ -44,44 +44,80 @@ STATIC_YOINK("PrintBacktraceUsingSymbols"); // for backtracing
STATIC_YOINK("malloc_inspect_all"); // for asan memory origin
STATIC_YOINK("GetSymbolByAddr"); // for asan memory origin
static struct sigaction g_oldcrashacts[8];
extern const unsigned char __oncrash_thunks[8][11];
struct CrashHandler {
int sig;
struct sigaction old;
};
static void InstallCrashHandlers(int extraflags) {
int e;
size_t i;
struct sigaction sa;
bzero(&sa, sizeof(sa));
sigfillset(&sa.sa_mask);
sa.sa_flags = SA_SIGINFO | SA_NODEFER | extraflags;
for (i = 0; i < ARRAYLEN(kCrashSigs); ++i) {
sigdelset(&sa.sa_mask, kCrashSigs[i]);
}
for (i = 0; i < ARRAYLEN(kCrashSigs); ++i) {
if (kCrashSigs[i]) {
sa.sa_sigaction = (sigaction_f)__oncrash_thunks[i];
e = errno;
sigaction(kCrashSigs[i], &sa, &g_oldcrashacts[i]);
errno = e;
}
}
static inline void __oncrash(int sig, struct siginfo *si, void *arg) {
#ifdef __x86_64__
__oncrash_amd64(sig, si, arg);
#elif defined(__aarch64__)
__oncrash_arm64(sig, si, arg);
#else
abort();
#endif
}
relegated void RestoreDefaultCrashSignalHandlers(void) {
static void __got_sigquit(int sig, struct siginfo *si, void *arg) {
__oncrash(sig, si, arg);
}
static void __got_sigfpe(int sig, struct siginfo *si, void *arg) {
__oncrash(sig, si, arg);
}
static void __got_sigill(int sig, struct siginfo *si, void *arg) {
__oncrash(sig, si, arg);
}
static void __got_sigsegv(int sig, struct siginfo *si, void *arg) {
__oncrash(sig, si, arg);
}
static void __got_sigtrap(int sig, struct siginfo *si, void *arg) {
__oncrash(sig, si, arg);
}
static void __got_sigabrt(int sig, struct siginfo *si, void *arg) {
__oncrash(sig, si, arg);
}
static void __got_sigbus(int sig, struct siginfo *si, void *arg) {
__oncrash(sig, si, arg);
}
static void __got_sigurg(int sig, struct siginfo *si, void *arg) {
__oncrash(sig, si, arg);
}
static void RemoveCrashHandler(void *arg) {
int e;
size_t i;
sigset_t ss;
struct CrashHandler *ch = arg;
strace_enabled(-1);
sigemptyset(&ss);
sigprocmask(SIG_SETMASK, &ss, NULL);
for (i = 0; i < ARRAYLEN(kCrashSigs); ++i) {
if (kCrashSigs[i]) {
e = errno;
sigaction(kCrashSigs[i], &g_oldcrashacts[i], NULL);
errno = e;
e = errno;
sigaction(ch->sig, &ch->old, NULL);
errno = e;
free(ch);
strace_enabled(+1);
}
static void InstallCrashHandler(int sig, sigaction_f thunk, int extraflags) {
int e;
struct sigaction sa;
struct CrashHandler *ch;
e = errno;
if ((ch = malloc(sizeof(*ch)))) {
ch->sig = sig;
sa.sa_sigaction = thunk;
sigfillset(&sa.sa_mask);
sigdelset(&sa.sa_mask, SIGQUIT);
sigdelset(&sa.sa_mask, SIGFPE);
sigdelset(&sa.sa_mask, SIGILL);
sigdelset(&sa.sa_mask, SIGSEGV);
sigdelset(&sa.sa_mask, SIGTRAP);
sigdelset(&sa.sa_mask, SIGABRT);
sigdelset(&sa.sa_mask, SIGBUS);
sigdelset(&sa.sa_mask, SIGURG);
sa.sa_flags = SA_SIGINFO | SA_NODEFER | extraflags;
if (!sigaction(sig, &sa, &ch->old)) {
__cxa_atexit(RemoveCrashHandler, ch, 0);
}
}
strace_enabled(+1);
errno = e;
}
/**
@ -100,33 +136,25 @@ relegated void RestoreDefaultCrashSignalHandlers(void) {
* useful, for example, if a program is caught in an infinite loop.
*/
void ShowCrashReports(void) {
int ef = 0;
struct sigaltstack ss;
_wantcrashreports = true;
/* <SYNC-LIST>: showcrashreports.c, oncrashthunks.S, oncrash.c */
kCrashSigs[0] = SIGQUIT; /* ctrl+\ aka ctrl+break */
kCrashSigs[1] = SIGFPE; /* 1 / 0 */
kCrashSigs[2] = SIGILL; /* illegal instruction */
kCrashSigs[3] = SIGSEGV; /* bad memory access */
kCrashSigs[4] = SIGTRAP; /* bad system call */
kCrashSigs[5] = SIGABRT; /* abort() called */
kCrashSigs[6] = SIGBUS; /* misaligned, noncanonical ptr, etc. */
kCrashSigs[7] = SIGURG; /* placeholder */
/* </SYNC-LIST>: showcrashreports.c, oncrashthunks.S, oncrash.c */
if (!IsWindows()) {
ef = SA_ONSTACK;
ss.ss_flags = 0;
ss.ss_size = GetStackSize();
// FreeBSD sigaltstack() will EFAULT if we use MAP_STACK here
// OpenBSD sigaltstack() auto-applies MAP_STACK to the memory
_npassert((ss.ss_sp = _mapanon(GetStackSize())));
_npassert(!sigaltstack(&ss, 0));
InstallCrashHandlers(SA_ONSTACK);
} else {
InstallCrashHandlers(0);
}
InstallCrashHandler(SIGQUIT, __got_sigquit, ef); // ctrl+\ aka ctrl+break
InstallCrashHandler(SIGFPE, __got_sigfpe, ef); // 1 / 0
InstallCrashHandler(SIGILL, __got_sigill, ef); // illegal instruction
InstallCrashHandler(SIGSEGV, __got_sigsegv, ef); // bad memory access
InstallCrashHandler(SIGTRAP, __got_sigtrap, ef); // bad system call
InstallCrashHandler(SIGABRT, __got_sigabrt, ef); // abort() called
InstallCrashHandler(SIGBUS, __got_sigbus, ef); // misalign, mmap i/o failed
InstallCrashHandler(SIGURG, __got_sigurg, ef); // placeholder
GetSymbolTable();
}
#else
void ShowCrashReports(void) {
}
#endif /* __x86_64__ */