cosmopolitan/libc/log/oncrash_arm64.c

/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│ vi: set et ft=c ts=2 sts=2 sw=2 fenc=utf-8                               :vi │
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2023 Justine Alexandra Roberts Tunney                              │
│                                                                              │
│ Permission to use, copy, modify, and/or distribute this software for         │
│ any purpose with or without fee is hereby granted, provided that the         │
│ above copyright notice and this permission notice appear in all copies.      │
│                                                                              │
│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL                │
│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED                │
│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE             │
│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL         │
│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR        │
│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER               │
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
│ PERFORMANCE OF THIS SOFTWARE.                                                │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "ape/sections.internal.h"
#include "libc/assert.h"
#include "libc/atomic.h"
#include "libc/calls/blockcancel.internal.h"
#include "libc/calls/calls.h"
#include "libc/calls/struct/aarch64.internal.h"
#include "libc/calls/struct/rusage.internal.h"
#include "libc/calls/struct/sigaction.h"
#include "libc/calls/struct/siginfo.h"
#include "libc/calls/struct/sigset.h"
#include "libc/calls/struct/sigset.internal.h"
#include "libc/calls/struct/ucontext.internal.h"
#include "libc/calls/struct/utsname.h"
#include "libc/calls/syscall-sysv.internal.h"
#include "libc/calls/ucontext.h"
#include "libc/cosmo.h"
#include "libc/cxxabi.h"
#include "libc/dce.h"
#include "libc/errno.h"
#include "libc/intrin/atomic.h"
#include "libc/intrin/describebacktrace.internal.h"
#include "libc/intrin/describeflags.internal.h"
#include "libc/intrin/kprintf.h"
#include "libc/log/internal.h"
#include "libc/log/log.h"
#include "libc/macros.internal.h"
#include "libc/nexgen32e/stackframe.h"
#include "libc/runtime/memtrack.internal.h"
#include "libc/runtime/runtime.h"
#include "libc/runtime/stack.h"
#include "libc/runtime/symbols.internal.h"
#include "libc/stdio/stdio.h"
#include "libc/str/str.h"
#include "libc/sysv/consts/auxv.h"
#include "libc/sysv/consts/sig.h"
#include "libc/thread/thread.h"
#ifdef __aarch64__

#define STACK_ERROR "error: not enough room on stack to print crash report\n"

#define RESET   "\e[0m"
#define BOLD    "\e[1m"
#define STRONG  "\e[30;101m"
#define RED     "\e[31;1m"
#define GREEN   "\e[32;1m"
#define BLUE    "\e[34;1m"
#define YELLOW  "\e[33;1m"
#define MAGENTA "\e[35;1m"

struct Buffer {
  char *p;
  int n;
  int i;
};

static relegated bool IsCode(uintptr_t p) {
  return __executable_start <= (uint8_t *)p && (uint8_t *)p < _etext;
}

static relegated void Append(struct Buffer *b, const char *fmt, ...) {
  va_list va;
  va_start(va, fmt);
  b->i += kvsnprintf(b->p + b->i, b->n - b->i, fmt, va);
  va_end(va);
}

static relegated const char *ColorRegister(int r) {
  if (__nocolor)
    return "";
  switch (r) {
    case 0:  // arg / res
    case 1:  // arg / res
    case 2:  // arg / res
    case 3:  // arg / res
    case 4:  // arg / res
    case 5:  // arg / res
    case 6:  // arg / res
    case 7:  // arg / res
      return GREEN;
    case 9:   // volatile
    case 10:  // volatile
    case 11:  // volatile
    case 12:  // volatile
    case 13:  // volatile
    case 14:  // volatile
    case 15:  // volatile
      return BLUE;
    case 19:  // saved
    case 20:  // saved
    case 21:  // saved
    case 22:  // saved
    case 23:  // saved
    case 24:  // saved
    case 25:  // saved
    case 26:  // saved
    case 27:  // saved
      return MAGENTA;
    case 18:  // platform register
    case 28:  // our tls register
    case 29:  // frame pointer
    case 30:  // return pointer
    case 31:  // stack pointer
      return RED;
    default:  // miscellaneous registers
      return YELLOW;
  }
}

static relegated bool AppendFileLine(struct Buffer *b, const char *addr2line,
                                     const char *debugbin, long addr) {
  ssize_t rc;
  char *p, *q, buf[128];
  int j, k, ws, pid, pfd[2];
  if (!debugbin || !*debugbin)
    return false;
  if (!addr2line || !*addr2line)
    return false;
  if (sys_pipe(pfd))
    return false;
  ksnprintf(buf, sizeof(buf), "%lx", addr);
  if ((pid = vfork()) == -1) {
    sys_close(pfd[1]);
    sys_close(pfd[0]);
    return false;
  }
  if (!pid) {
    sys_close(pfd[0]);
    sys_dup2(pfd[1], 1, 0);
    sys_close(2);
    sys_execve(
        addr2line,
        (char *const[]){(char *)addr2line, "-pifCe", (char *)debugbin, buf, 0},
        (char *const[]){0});
    _Exit(127);
  }
  sys_close(pfd[1]);
  // copy addr2line stdout to buffer. normally it is "file:line\n".
  // however additional lines can get created for inline functions.
  j = b->i;
  Append(b, "in ");
  k = b->i;
  while ((rc = sys_read(pfd[0], buf, sizeof(buf))) > 0) {
    Append(b, "%.*s", (int)rc, buf);
  }
  // remove the annoying `foo.c:123 (discriminator 3)` suffixes, because
  // they break emacs, and who on earth knows what those things mean lol
  while ((p = memmem(b->p + k, b->i - k, " (discriminator ", 16)) &&
         (q = memchr(p + 16, '\n', (b->p + b->i) - (p + 16)))) {
    memmove(p, q, (b->p + b->i) - q);
    b->i -= q - p;
  }
  // mop up after the process and sanity check captured text
  sys_close(pfd[0]);
  if (sys_wait4(pid, &ws, 0, 0) != -1 && !ws && b->p[k] != ':' &&
      b->p[k] != '?' && b->p[b->i - 1] == '\n') {
    --b->i;  // chomp last newline
    return true;
  } else {
    b->i = j;  // otherwise reset the buffer
    return false;
  }
}

static relegated char *GetSymbolName(struct SymbolTable *st, int symbol) {
  char *str;
  static char buf[8192];
  if (!(str = __get_symbol_name(st, symbol)))
    return str;
  if (!__is_mangled(str))
    return str;
  __demangle(buf, str, sizeof(buf));
  return buf;
}

static relegated void __oncrash_impl(int sig, siginfo_t *si, ucontext_t *ctx) {
#pragma GCC push_options
#pragma GCC diagnostic ignored "-Walloca-larger-than="
  long size = __get_safe_size(10000, 4096);
  if (size < 80) {
    // almost certainly guaranteed to succeed
    klog(STACK_ERROR, sizeof(STACK_ERROR) - 1);
    __restore_tty();
    __minicrash(sig, si, ctx);
    return;
  }
  char *buf = alloca(size);
  CheckLargeStackAllocation(buf, size);
#pragma GCC pop_options
  int i, j;
  const char *kind;
  const char *reset;
  const char *strong;
  char host[64] = "unknown";
  struct utsname names = {0};
  struct Buffer b[1] = {{buf, size}};
  b->p[b->i++] = '\n';
  __restore_tty();
  uname(&names);
  gethostname(host, sizeof(host));
  reset = !__nocolor ? RESET : "";
  strong = !__nocolor ? STRONG : "";
  if (__is_stack_overflow(si, ctx)) {
    kind = "\e[7mStack Overflow\e[0m";
  } else {
    kind = DescribeSiCode(sig, si->si_code);
  }
  Append(b, "%serror%s: Uncaught %G (%s) on %s pid %d tid %d\n", strong, reset,
         sig, kind, host, getpid(), gettid());
  if (program_invocation_name) {
    Append(b, " %s\n", __program_executable_name);
  }
  if (errno) {
    Append(b, " %s\n", strerror(errno));
  }
  Append(b, " %s %s %s %s\n", names.sysname, names.version, names.nodename,
         names.release);
  Append(
      b, " cosmoaddr2line %s %lx %s\n", FindDebugBinary(),
      ctx ? ctx->uc_mcontext.PC : 0,
      DescribeBacktrace(ctx ? (struct StackFrame *)ctx->uc_mcontext.BP
                            : (struct StackFrame *)__builtin_frame_address(0)));
  if (ctx) {
    long pc;
    int addend, symbol;
    const char *debugbin;
    const char *addr2line;
    struct StackFrame *fp;
    struct SymbolTable *st;
    struct fpsimd_context *vc;

    st = GetSymbolTable();
    debugbin = FindDebugBinary();
    addr2line = GetAddr2linePath();

    if (sig == SIGFPE ||   //
        sig == SIGILL ||   //
        sig == SIGBUS ||   //
        sig == SIGSEGV ||  //
        sig == SIGTRAP) {
      Append(b, " faulting address is %016lx\n", si->si_addr);
    }

    // PRINT REGISTERS
    for (i = 0; i < 8; ++i) {
      Append(b, " ");
      for (j = 0; j < 4; ++j) {
        int r = 8 * j + i;
        if (j)
          Append(b, " ");
        Append(b, "%s%016lx%s x%d%s", ColorRegister(r),
               ctx->uc_mcontext.regs[r], reset, r, r == 8 || r == 9 ? " " : "");
      }
      Append(b, "\n");
    }

    // PRINT VECTORS
    vc = (struct fpsimd_context *)ctx->uc_mcontext.__reserved;
    if (vc->head.magic == FPSIMD_MAGIC) {
      int n = 16;
      while (n && !vc->vregs[n - 1] && !vc->vregs[n - 2])
        n -= 2;
      for (i = 0; i * 2 < n; ++i) {
        Append(b, " ");
        for (j = 0; j < 2; ++j) {
          int r = j + 2 * i;
          if (j)
            Append(b, " ");
          Append(b, "%016lx ..%s %016lx v%d%s", (long)(vc->vregs[r] >> 64),
                 !j ? "" : ".", (long)vc->vregs[r], r, r < 10 ? " " : "");
        }
        Append(b, "\n");
      }
    }

    // PRINT CURRENT LOCATION
    //
    // We can get the address of the currently executing function by
    // simply examining the program counter.
    pc = ctx->uc_mcontext.pc;
    Append(b, " %016lx sp %lx pc", ctx->uc_mcontext.sp, pc);
    if (pc && st && (symbol = __get_symbol(st, pc))) {
      addend = pc - st->addr_base;
      addend -= st->symbols[symbol].x;
      Append(b, " ");
      if (!AppendFileLine(b, addr2line, debugbin, pc)) {
        Append(b, "%s", GetSymbolName(st, symbol));
        if (addend)
          Append(b, "%+d", addend);
      }
    }
    Append(b, "\n");

    // PRINT LINKED LOCATION
    //
    // The x30 register can usually tell us the address of the parent
    // function. This can help us determine the caller in cases where
    // stack frames aren't being generated by the compiler; but if we
    // have stack frames, then we need to ensure this won't duplicate
    // the first element of the frame pointer backtrace below.
    fp = (struct StackFrame *)ctx->uc_mcontext.regs[29];
    if (IsCode((pc = ctx->uc_mcontext.regs[30]))) {
      Append(b, " %016lx sp %lx lr", ctx->uc_mcontext.sp, pc);
      if (pc && st && (symbol = __get_symbol(st, pc))) {
        addend = pc - st->addr_base;
        addend -= st->symbols[symbol].x;
        Append(b, " ");
        if (!AppendFileLine(b, addr2line, debugbin, pc)) {
          Append(b, "%s", GetSymbolName(st, symbol));
          if (addend)
            Append(b, "%+d", addend);
        }
      }
      Append(b, "\n");
      if (fp && !kisdangerous(fp) && pc == fp->addr) {
        fp = fp->next;
      }
    }

    // PRINT FRAME POINTERS
    //
    // The prologues and epilogues of non-leaf functions should save
    // the frame pointer (x29) and return address (x30) to the stack
    // and then set x29 to sp, which is the address of the new frame
    // effectively creating a daisy chain letting us trace back into
    // the origin of execution, e.g. _start(), or sys_clone_linux().
    for (i = 0; fp; fp = fp->next) {
      if (kisdangerous(fp)) {
        Append(b, " %016lx <dangerous fp>\n", fp);
        break;
      }
      if (++i == 100) {
        Append(b, " <truncated backtrace>\n");
        break;
      }
      if (st && (pc = fp->addr)) {
        if ((symbol = __get_symbol(st, pc))) {
          addend = pc - st->addr_base;
          addend -= st->symbols[symbol].x;
        } else {
          addend = 0;
        }
      } else {
        symbol = 0;
        addend = 0;
      }
      Append(b, " %016lx fp %lx lr ", fp, pc);
      if (!AppendFileLine(b, addr2line, debugbin, pc) && st) {
        Append(b, "%s", GetSymbolName(st, symbol));
        if (addend)
          Append(b, "%+d", addend);
      }
      Append(b, "\n");
    }
  }
  b->p[b->n - 1] = '\n';
  klog(b->p, MIN(b->i, b->n));
}

static inline void SpinLock(atomic_uint *lock) {
  int x;
  for (;;) {
    x = atomic_exchange_explicit(lock, 1, memory_order_acquire);
    if (!x)
      break;
  }
}

static inline void SpinUnlock(atomic_uint *lock) {
  atomic_store_explicit(lock, 0, memory_order_release);
}

relegated void __oncrash(int sig, siginfo_t *si, void *arg) {
  static atomic_uint lock;
  ftrace_enabled(-1);
  strace_enabled(-1);
  BLOCK_CANCELATION;
  SpinLock(&lock);
  __oncrash_impl(sig, si, arg);

  // unlike amd64, the instruction pointer on arm64 isn't advanced past
  // the debugger breakpoint instruction automatically. we need this so
  // execution can resume after __builtin_trap().
  if (arg && sig == SIGTRAP)
    ((ucontext_t *)arg)->uc_mcontext.PC += 4;

  // ensure execution doesn't resume for anything but SIGTRAP / SIGQUIT
  if (arg && sig != SIGTRAP && sig != SIGQUIT) {
    if (!IsXnu()) {
      sigaddset(&((ucontext_t *)arg)->uc_sigmask, sig);
    } else {
      sigdelset(&((ucontext_t *)arg)->uc_sigmask, sig);
      struct sigaction sa;
      sigemptyset(&sa.sa_mask);
      sa.sa_handler = SIG_DFL;
      sa.sa_flags = 0;
      sigaction(sig, &sa, 0);
    }
  }

  SpinUnlock(&lock);
  ALLOW_CANCELATION;
  strace_enabled(+1);
  ftrace_enabled(+1);
}

#endif /* __aarch64__ */