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      1 /*
      2  * Copyright (C) 2012 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 <ctype.h>
     30 #include <inttypes.h>
     31 #include <stdio.h>
     32 #include <string.h>
     33 #include <stdlib.h>
     34 
     35 #include "debug_mapinfo.h"
     36 #include "malloc_debug_disable.h"
     37 
     38 // Format of /proc/<PID>/maps:
     39 //   6f000000-6f01e000 rwxp 00000000 00:0c 16389419   /system/lib/libcomposer.so
     40 static mapinfo_t* parse_maps_line(char* line) {
     41   uintptr_t start;
     42   uintptr_t end;
     43   int name_pos;
     44   if (sscanf(line, "%" PRIxPTR "-%" PRIxPTR " %*4s %*x %*x:%*x %*d%n", &start,
     45              &end, &name_pos) < 2) {
     46     return NULL;
     47   }
     48 
     49   while (isspace(line[name_pos])) {
     50     name_pos += 1;
     51   }
     52   const char* name = line + name_pos;
     53   size_t name_len = strlen(name);
     54   if (name_len && name[name_len - 1] == '\n') {
     55     name_len -= 1;
     56   }
     57 
     58   mapinfo_t* mi = reinterpret_cast<mapinfo_t*>(calloc(1, sizeof(mapinfo_t) + name_len + 1));
     59   if (mi) {
     60     mi->start = start;
     61     mi->end = end;
     62     memcpy(mi->name, name, name_len);
     63     mi->name[name_len] = '\0';
     64   }
     65   return mi;
     66 }
     67 
     68 __LIBC_HIDDEN__ mapinfo_t* mapinfo_create(pid_t pid) {
     69   ScopedDisableDebugCalls disable;
     70 
     71   struct mapinfo_t* milist = NULL;
     72   char data[1024]; // Used to read lines as well as to construct the filename.
     73   snprintf(data, sizeof(data), "/proc/%d/maps", pid);
     74   FILE* fp = fopen(data, "r");
     75   if (fp != NULL) {
     76     while (fgets(data, sizeof(data), fp) != NULL) {
     77       mapinfo_t* mi = parse_maps_line(data);
     78       if (mi) {
     79         mi->next = milist;
     80         milist = mi;
     81       }
     82     }
     83     fclose(fp);
     84   }
     85   return milist;
     86 }
     87 
     88 __LIBC_HIDDEN__ void mapinfo_destroy(mapinfo_t* mi) {
     89   ScopedDisableDebugCalls disable;
     90 
     91   while (mi != NULL) {
     92     mapinfo_t* del = mi;
     93     mi = mi->next;
     94     free(del);
     95   }
     96 }
     97 
     98 // Find the containing map info for the PC.
     99 __LIBC_HIDDEN__ const mapinfo_t* mapinfo_find(mapinfo_t* mi, uintptr_t pc, uintptr_t* rel_pc) {
    100   for (; mi != NULL; mi = mi->next) {
    101     if ((pc >= mi->start) && (pc < mi->end)) {
    102       *rel_pc = pc - mi->start;
    103       return mi;
    104     }
    105   }
    106   *rel_pc = pc;
    107   return NULL;
    108 }
    109