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      1 /*
      2  * Copyright (C) 2008 The Android Open Source Project
      3  * All rights reserved.
      4  *
      5  * Redistribution and use in source and binary forms, with or without
      6  * modification, are permitted provided that the following conditions
      7  * are met:
      8  *  * Redistributions of source code must retain the above copyright
      9  *    notice, this list of conditions and the following disclaimer.
     10  *  * Redistributions in binary form must reproduce the above copyright
     11  *    notice, this list of conditions and the following disclaimer in
     12  *    the documentation and/or other materials provided with the
     13  *    distribution.
     14  *
     15  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     16  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     17  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
     18  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
     19  * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
     20  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
     21  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
     22  * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
     23  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
     24  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
     25  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     26  * SUCH DAMAGE.
     27  */
     28 
     29 #include <pthread.h>
     30 
     31 #include <inttypes.h>
     32 #include <stdio.h>
     33 #include <sys/resource.h>
     34 #include <unistd.h>
     35 
     36 #include "private/bionic_string_utils.h"
     37 #include "private/ErrnoRestorer.h"
     38 #include "private/libc_logging.h"
     39 #include "pthread_internal.h"
     40 
     41 int pthread_attr_init(pthread_attr_t* attr) {
     42   attr->flags = 0;
     43   attr->stack_base = NULL;
     44   attr->stack_size = PTHREAD_STACK_SIZE_DEFAULT;
     45   attr->guard_size = PAGE_SIZE;
     46   attr->sched_policy = SCHED_NORMAL;
     47   attr->sched_priority = 0;
     48   return 0;
     49 }
     50 
     51 int pthread_attr_destroy(pthread_attr_t* attr) {
     52   memset(attr, 0x42, sizeof(pthread_attr_t));
     53   return 0;
     54 }
     55 
     56 int pthread_attr_setdetachstate(pthread_attr_t* attr, int state) {
     57   if (state == PTHREAD_CREATE_DETACHED) {
     58     attr->flags |= PTHREAD_ATTR_FLAG_DETACHED;
     59   } else if (state == PTHREAD_CREATE_JOINABLE) {
     60     attr->flags &= ~PTHREAD_ATTR_FLAG_DETACHED;
     61   } else {
     62     return EINVAL;
     63   }
     64   return 0;
     65 }
     66 
     67 int pthread_attr_getdetachstate(const pthread_attr_t* attr, int* state) {
     68   *state = (attr->flags & PTHREAD_ATTR_FLAG_DETACHED) ? PTHREAD_CREATE_DETACHED : PTHREAD_CREATE_JOINABLE;
     69   return 0;
     70 }
     71 
     72 int pthread_attr_setschedpolicy(pthread_attr_t* attr, int policy) {
     73   attr->sched_policy = policy;
     74   return 0;
     75 }
     76 
     77 int pthread_attr_getschedpolicy(const pthread_attr_t* attr, int* policy) {
     78   *policy = attr->sched_policy;
     79   return 0;
     80 }
     81 
     82 int pthread_attr_setschedparam(pthread_attr_t* attr, const sched_param* param) {
     83   attr->sched_priority = param->sched_priority;
     84   return 0;
     85 }
     86 
     87 int pthread_attr_getschedparam(const pthread_attr_t* attr, sched_param* param) {
     88   param->sched_priority = attr->sched_priority;
     89   return 0;
     90 }
     91 
     92 int pthread_attr_setstacksize(pthread_attr_t* attr, size_t stack_size) {
     93   if (stack_size < PTHREAD_STACK_MIN) {
     94     return EINVAL;
     95   }
     96   attr->stack_size = stack_size;
     97   return 0;
     98 }
     99 
    100 int pthread_attr_getstacksize(const pthread_attr_t* attr, size_t* stack_size) {
    101   void* unused;
    102   return pthread_attr_getstack(attr, &unused, stack_size);
    103 }
    104 
    105 int pthread_attr_setstack(pthread_attr_t* attr, void* stack_base, size_t stack_size) {
    106   if ((stack_size & (PAGE_SIZE - 1) || stack_size < PTHREAD_STACK_MIN)) {
    107     return EINVAL;
    108   }
    109   if (reinterpret_cast<uintptr_t>(stack_base) & (PAGE_SIZE - 1)) {
    110     return EINVAL;
    111   }
    112   attr->stack_base = stack_base;
    113   attr->stack_size = stack_size;
    114   return 0;
    115 }
    116 
    117 static int __pthread_attr_getstack_main_thread(void** stack_base, size_t* stack_size) {
    118   ErrnoRestorer errno_restorer;
    119 
    120   rlimit stack_limit;
    121   if (getrlimit(RLIMIT_STACK, &stack_limit) == -1) {
    122     return errno;
    123   }
    124 
    125   // If the current RLIMIT_STACK is RLIM_INFINITY, only admit to an 8MiB stack for sanity's sake.
    126   if (stack_limit.rlim_cur == RLIM_INFINITY) {
    127     stack_limit.rlim_cur = 8 * 1024 * 1024;
    128   }
    129 
    130   // It shouldn't matter which thread we are because we're just looking for "[stack]", but
    131   // valgrind seems to mess with the stack enough that the kernel will report "[stack:pid]"
    132   // instead if you look in /proc/self/maps, so we need to look in /proc/pid/task/pid/maps.
    133   char path[64];
    134   snprintf(path, sizeof(path), "/proc/self/task/%d/maps", getpid());
    135   FILE* fp = fopen(path, "re");
    136   if (fp == NULL) {
    137     return errno;
    138   }
    139   char line[BUFSIZ];
    140   while (fgets(line, sizeof(line), fp) != NULL) {
    141     if (ends_with(line, " [stack]\n")) {
    142       uintptr_t lo, hi;
    143       if (sscanf(line, "%" SCNxPTR "-%" SCNxPTR, &lo, &hi) == 2) {
    144         *stack_size = stack_limit.rlim_cur;
    145         *stack_base = reinterpret_cast<void*>(hi - *stack_size);
    146         fclose(fp);
    147         return 0;
    148       }
    149     }
    150   }
    151   __libc_fatal("No [stack] line found in \"%s\"!", path);
    152 }
    153 
    154 int pthread_attr_getstack(const pthread_attr_t* attr, void** stack_base, size_t* stack_size) {
    155   if ((attr->flags & PTHREAD_ATTR_FLAG_MAIN_THREAD) != 0) {
    156     return __pthread_attr_getstack_main_thread(stack_base, stack_size);
    157   }
    158   *stack_base = attr->stack_base;
    159   *stack_size = attr->stack_size;
    160   return 0;
    161 }
    162 
    163 int pthread_attr_setguardsize(pthread_attr_t* attr, size_t guard_size) {
    164   attr->guard_size = guard_size;
    165   return 0;
    166 }
    167 
    168 int pthread_attr_getguardsize(const pthread_attr_t* attr, size_t* guard_size) {
    169   *guard_size = attr->guard_size;
    170   return 0;
    171 }
    172 
    173 int pthread_getattr_np(pthread_t t, pthread_attr_t* attr) {
    174   *attr = reinterpret_cast<pthread_internal_t*>(t)->attr;
    175   return 0;
    176 }
    177 
    178 int pthread_attr_setscope(pthread_attr_t*, int scope) {
    179   if (scope == PTHREAD_SCOPE_SYSTEM) {
    180     return 0;
    181   }
    182   if (scope == PTHREAD_SCOPE_PROCESS) {
    183     return ENOTSUP;
    184   }
    185   return EINVAL;
    186 }
    187 
    188 int pthread_attr_getscope(const pthread_attr_t*, int* scope) {
    189   *scope = PTHREAD_SCOPE_SYSTEM;
    190   return 0;
    191 }
    192