//===-- sanitizer_linux.h ---------------------------------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// Linux-specific syscall wrappers and classes.
//
//===----------------------------------------------------------------------===//
#ifndef SANITIZER_LINUX_H
#define SANITIZER_LINUX_H

#include "sanitizer_platform.h"
#if SANITIZER_FREEBSD || SANITIZER_LINUX || SANITIZER_NETBSD || \
    SANITIZER_SOLARIS
#  include "sanitizer_common.h"
#  include "sanitizer_internal_defs.h"
#  include "sanitizer_platform_limits_freebsd.h"
#  include "sanitizer_platform_limits_netbsd.h"
#  include "sanitizer_platform_limits_posix.h"
#  include "sanitizer_platform_limits_solaris.h"
#  include "sanitizer_posix.h"

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

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;

struct ProcSelfMapsBuff {
  char *data;
  uptr mmaped_size;
  uptr len;
};

struct MemoryMappingLayoutData {
  ProcSelfMapsBuff proc_self_maps;
  const char *current;
};

void ReadProcMaps(ProcSelfMapsBuff *proc_maps);

// 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);

void SetSigProcMask(__sanitizer_sigset_t *set, __sanitizer_sigset_t *oldset);
void BlockSignals(__sanitizer_sigset_t *oldset = nullptr);
struct ScopedBlockSignals {
  explicit ScopedBlockSignals(__sanitizer_sigset_t *copy);
  ~ScopedBlockSignals();

  ScopedBlockSignals &operator=(const ScopedBlockSignals &) = delete;
  ScopedBlockSignals(const ScopedBlockSignals &) = delete;

 private:
  __sanitizer_sigset_t saved_;
};

#  if SANITIZER_GLIBC
uptr internal_clock_gettime(__sanitizer_clockid_t clk_id, void *tp);
#  endif

// Linux-only syscalls.
#  if SANITIZER_LINUX
uptr internal_prctl(int option, uptr arg2, uptr arg3, uptr arg4, uptr arg5);
#    if defined(__x86_64__)
uptr internal_arch_prctl(int option, uptr arg2);
#    endif
// 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);
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__) || SANITIZER_RISCV64 || SANITIZER_LOONGARCH64
uptr internal_clone(int (*fn)(void *), void *child_stack, int flags, void *arg,
                    int *parent_tidptr, void *newtls, int *child_tidptr);
#    endif
int internal_uname(struct utsname *buf);
#  elif SANITIZER_FREEBSD
uptr internal_procctl(int type, int id, int cmd, void *data);
void internal_sigdelset(__sanitizer_sigset_t *set, int signum);
#  elif SANITIZER_NETBSD
void internal_sigdelset(__sanitizer_sigset_t *set, int signum);
uptr internal_clone(int (*fn)(void *), void *child_stack, int flags, void *arg);
#  endif  // SANITIZER_LINUX

// This class reads thread IDs from /proc/<pid>/task using only syscalls.
class ThreadLister {
 public:
  explicit ThreadLister(pid_t pid);
  enum Result {
    Error,
    Incomplete,
    Ok,
  };
  Result ListThreads(InternalMmapVector<tid_t> *threads);
  const char *LoadStatus(tid_t tid);

 private:
  bool IsAlive(tid_t tid);

  InternalScopedString task_path_;
  InternalScopedString status_path_;
  InternalMmapVector<char> buffer_;
};

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

// 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));

// Releases memory pages entirely within the [beg, end] address range.
// The pages no longer count toward RSS; reads are guaranteed to return 0.
// Requires (but does not verify!) that pages are MAP_PRIVATE.
inline void ReleaseMemoryPagesToOSAndZeroFill(uptr beg, uptr end) {
  // man madvise on Linux promises zero-fill for anonymous private pages.
  // Testing shows the same behaviour for private (but not anonymous) mappings
  // of shm_open() files, as long as the underlying file is untouched.
  CHECK(SANITIZER_LINUX);
  ReleaseMemoryPagesToOS(beg, end);
}

#  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(__riscv)
#      define __get_tls()                   \
        ({                                  \
          void **__v;                       \
          __asm__("mv %0, tp" : "=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 sanitizers starting
// with Q, given that Android currently doesn't support ELF TLS. It is used to
// store sanitizer thread specific data.
static const int TLS_SLOT_SANITIZER = 6;

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

#  endif  // SANITIZER_ANDROID

}  // namespace __sanitizer

#endif
#endif  // SANITIZER_LINUX_H
