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      1 //===-- sanitizer_linux.h ---------------------------------------*- C++ -*-===//
      2 //
      3 //                     The LLVM Compiler Infrastructure
      4 //
      5 // This file is distributed under the University of Illinois Open Source
      6 // License. See LICENSE.TXT for details.
      7 //
      8 //===----------------------------------------------------------------------===//
      9 //
     10 // Linux-specific syscall wrappers and classes.
     11 //
     12 //===----------------------------------------------------------------------===//
     13 #ifndef SANITIZER_LINUX_H
     14 #define SANITIZER_LINUX_H
     15 
     16 #include "sanitizer_platform.h"
     17 #if SANITIZER_FREEBSD || SANITIZER_LINUX || SANITIZER_NETBSD ||                \
     18     SANITIZER_OPENBSD || SANITIZER_SOLARIS
     19 #include "sanitizer_common.h"
     20 #include "sanitizer_internal_defs.h"
     21 #include "sanitizer_platform_limits_freebsd.h"
     22 #include "sanitizer_platform_limits_netbsd.h"
     23 #include "sanitizer_platform_limits_openbsd.h"
     24 #include "sanitizer_platform_limits_posix.h"
     25 #include "sanitizer_platform_limits_solaris.h"
     26 #include "sanitizer_posix.h"
     27 
     28 struct link_map;  // Opaque type returned by dlopen().
     29 
     30 namespace __sanitizer {
     31 // Dirent structure for getdents(). Note that this structure is different from
     32 // the one in <dirent.h>, which is used by readdir().
     33 struct linux_dirent;
     34 
     35 struct ProcSelfMapsBuff {
     36   char *data;
     37   uptr mmaped_size;
     38   uptr len;
     39 };
     40 
     41 struct MemoryMappingLayoutData {
     42   ProcSelfMapsBuff proc_self_maps;
     43   const char *current;
     44 };
     45 
     46 void ReadProcMaps(ProcSelfMapsBuff *proc_maps);
     47 
     48 // Syscall wrappers.
     49 uptr internal_getdents(fd_t fd, struct linux_dirent *dirp, unsigned int count);
     50 uptr internal_sigaltstack(const void* ss, void* oss);
     51 uptr internal_sigprocmask(int how, __sanitizer_sigset_t *set,
     52     __sanitizer_sigset_t *oldset);
     53 uptr internal_clock_gettime(__sanitizer_clockid_t clk_id, void *tp);
     54 
     55 // Linux-only syscalls.
     56 #if SANITIZER_LINUX
     57 uptr internal_prctl(int option, uptr arg2, uptr arg3, uptr arg4, uptr arg5);
     58 // Used only by sanitizer_stoptheworld. Signal handlers that are actually used
     59 // (like the process-wide error reporting SEGV handler) must use
     60 // internal_sigaction instead.
     61 int internal_sigaction_norestorer(int signum, const void *act, void *oldact);
     62 #if (defined(__x86_64__) || SANITIZER_MIPS64) && !SANITIZER_GO
     63 // Uses a raw system call to avoid interceptors.
     64 int internal_sigaction_syscall(int signum, const void *act, void *oldact);
     65 #endif
     66 void internal_sigdelset(__sanitizer_sigset_t *set, int signum);
     67 #if defined(__x86_64__) || defined(__mips__) || defined(__aarch64__) \
     68   || defined(__powerpc64__) || defined(__s390__) || defined(__i386__) \
     69   || defined(__arm__)
     70 uptr internal_clone(int (*fn)(void *), void *child_stack, int flags, void *arg,
     71                     int *parent_tidptr, void *newtls, int *child_tidptr);
     72 #endif
     73 #elif SANITIZER_FREEBSD
     74 void internal_sigdelset(__sanitizer_sigset_t *set, int signum);
     75 #endif  // SANITIZER_LINUX
     76 
     77 // This class reads thread IDs from /proc/<pid>/task using only syscalls.
     78 class ThreadLister {
     79  public:
     80   explicit ThreadLister(pid_t pid);
     81   ~ThreadLister();
     82   enum Result {
     83     Error,
     84     Incomplete,
     85     Ok,
     86   };
     87   Result ListThreads(InternalMmapVector<tid_t> *threads);
     88 
     89  private:
     90   bool IsAlive(int tid);
     91 
     92   pid_t pid_;
     93   int descriptor_ = -1;
     94   InternalMmapVector<char> buffer_;
     95 };
     96 
     97 // Exposed for testing.
     98 uptr ThreadDescriptorSize();
     99 uptr ThreadSelf();
    100 uptr ThreadSelfOffset();
    101 
    102 // Matches a library's file name against a base name (stripping path and version
    103 // information).
    104 bool LibraryNameIs(const char *full_name, const char *base_name);
    105 
    106 // Call cb for each region mapped by map.
    107 void ForEachMappedRegion(link_map *map, void (*cb)(const void *, uptr));
    108 
    109 #if SANITIZER_ANDROID
    110 
    111 #if defined(__aarch64__)
    112 # define __get_tls() \
    113     ({ void** __v; __asm__("mrs %0, tpidr_el0" : "=r"(__v)); __v; })
    114 #elif defined(__arm__)
    115 # define __get_tls() \
    116     ({ void** __v; __asm__("mrc p15, 0, %0, c13, c0, 3" : "=r"(__v)); __v; })
    117 #elif defined(__mips__)
    118 // On mips32r1, this goes via a kernel illegal instruction trap that's
    119 // optimized for v1.
    120 # define __get_tls() \
    121     ({ register void** __v asm("v1"); \
    122        __asm__(".set    push\n" \
    123                ".set    mips32r2\n" \
    124                "rdhwr   %0,$29\n" \
    125                ".set    pop\n" : "=r"(__v)); \
    126        __v; })
    127 #elif defined(__i386__)
    128 # define __get_tls() \
    129     ({ void** __v; __asm__("movl %%gs:0, %0" : "=r"(__v)); __v; })
    130 #elif defined(__x86_64__)
    131 # define __get_tls() \
    132     ({ void** __v; __asm__("mov %%fs:0, %0" : "=r"(__v)); __v; })
    133 #else
    134 #error "Unsupported architecture."
    135 #endif
    136 
    137 // The Android Bionic team has allocated a TLS slot for sanitizers starting
    138 // with Q, given that Android currently doesn't support ELF TLS. It is used to
    139 // store sanitizer thread specific data.
    140 static const int TLS_SLOT_SANITIZER = 6;
    141 
    142 ALWAYS_INLINE uptr *get_android_tls_ptr() {
    143   return reinterpret_cast<uptr *>(&__get_tls()[TLS_SLOT_SANITIZER]);
    144 }
    145 
    146 #endif  // SANITIZER_ANDROID
    147 
    148 }  // namespace __sanitizer
    149 
    150 #endif
    151 #endif  // SANITIZER_LINUX_H
    152