//===-- sanitizer_linux.h ---------------------------------------*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// Linux-specific syscall wrappers and classes.
//
//===----------------------------------------------------------------------===//
#ifndef SANITIZER_LINUX_H
#define SANITIZER_LINUX_H

#include "sanitizer_platform.h"
#if SANITIZER_FREEBSD || SANITIZER_LINUX
#include "sanitizer_common.h"
#include "sanitizer_internal_defs.h"
#include "sanitizer_posix.h"
#include "sanitizer_platform_limits_posix.h"

struct link_map;  // Opaque type returned by dlopen().

namespace __sanitizer {
// Dirent structure for getdents(). Note that this structure is different from
// the one in <dirent.h>, which is used by readdir().
struct linux_dirent;

// Syscall wrappers.
uptr internal_getdents(fd_t fd, struct linux_dirent *dirp, unsigned int count);
uptr internal_sigaltstack(const void* ss, void* oss);
uptr internal_sigprocmask(int how, __sanitizer_sigset_t *set,
    __sanitizer_sigset_t *oldset);

// Linux-only syscalls.
#if SANITIZER_LINUX
uptr internal_prctl(int option, uptr arg2, uptr arg3, uptr arg4, uptr arg5);
// Used only by sanitizer_stoptheworld. Signal handlers that are actually used
// (like the process-wide error reporting SEGV handler) must use
// internal_sigaction instead.
int internal_sigaction_norestorer(int signum, const void *act, void *oldact);
#if (defined(__x86_64__) || SANITIZER_MIPS64) && !SANITIZER_GO
// Uses a raw system call to avoid interceptors.
int internal_sigaction_syscall(int signum, const void *act, void *oldact);
#endif
void internal_sigdelset(__sanitizer_sigset_t *set, int signum);
#if defined(__x86_64__) || defined(__mips__) || defined(__aarch64__) \
  || defined(__powerpc64__) || defined(__s390__) || defined(__i386__) \
  || defined(__arm__)
uptr internal_clone(int (*fn)(void *), void *child_stack, int flags, void *arg,
                    int *parent_tidptr, void *newtls, int *child_tidptr);
#endif
#endif  // SANITIZER_LINUX

// This class reads thread IDs from /proc/<pid>/task using only syscalls.
class ThreadLister {
 public:
  explicit ThreadLister(int pid);
  ~ThreadLister();
  // GetNextTID returns -1 if the list of threads is exhausted, or if there has
  // been an error.
  int GetNextTID();
  void Reset();
  bool error();

 private:
  bool GetDirectoryEntries();

  int pid_;
  int descriptor_;
  InternalScopedBuffer<char> buffer_;
  bool error_;
  struct linux_dirent* entry_;
  int bytes_read_;
};

// Exposed for testing.
uptr ThreadDescriptorSize();
uptr ThreadSelf();
uptr ThreadSelfOffset();

// Matches a library's file name against a base name (stripping path and version
// information).
bool LibraryNameIs(const char *full_name, const char *base_name);

// Call cb for each region mapped by map.
void ForEachMappedRegion(link_map *map, void (*cb)(const void *, uptr));

#if SANITIZER_ANDROID

#if defined(__aarch64__)
# define __get_tls() \
    ({ void** __v; __asm__("mrs %0, tpidr_el0" : "=r"(__v)); __v; })
#elif defined(__arm__)
# define __get_tls() \
    ({ void** __v; __asm__("mrc p15, 0, %0, c13, c0, 3" : "=r"(__v)); __v; })
#elif defined(__mips__)
// On mips32r1, this goes via a kernel illegal instruction trap that's
// optimized for v1.
# define __get_tls() \
    ({ register void** __v asm("v1"); \
       __asm__(".set    push\n" \
               ".set    mips32r2\n" \
               "rdhwr   %0,$29\n" \
               ".set    pop\n" : "=r"(__v)); \
       __v; })
#elif defined(__i386__)
# define __get_tls() \
    ({ void** __v; __asm__("movl %%gs:0, %0" : "=r"(__v)); __v; })
#elif defined(__x86_64__)
# define __get_tls() \
    ({ void** __v; __asm__("mov %%fs:0, %0" : "=r"(__v)); __v; })
#else
#error "Unsupported architecture."
#endif

// The Android Bionic team has allocated a TLS slot for TSan starting with N,
// given that Android currently doesn't support ELF TLS. It is used to store
// Sanitizers thread specific data.
static const int TLS_SLOT_TSAN = 8;

ALWAYS_INLINE uptr *get_android_tls_ptr() {
  return reinterpret_cast<uptr *>(&__get_tls()[TLS_SLOT_TSAN]);
}

#endif  // SANITIZER_ANDROID

}  // namespace __sanitizer

#endif  // SANITIZER_FREEBSD || SANITIZER_LINUX
#endif  // SANITIZER_LINUX_H