src/lib/meminfo/meminfo.c

   1 /* Copyright (c) 2003-2004, Roger Dingledine
   2  * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
   3  * Copyright (c) 2007-2021, The Tor Project, Inc. */
   4 /* See LICENSE for licensing information */
   5
   6 /**
   7  * \file meminfo.c
   8  *
   9  * \brief Functions to query total memory, and access meta-information about
  10  * the allocator.
  11  **/
  12
  13 #include "lib/meminfo/meminfo.h"
  14
  15 #include "lib/cc/compat_compiler.h"
  16 #include "lib/cc/torint.h"
  17 #include "lib/fs/files.h"
  18 #include "lib/log/log.h"
  19 #include "lib/malloc/malloc.h"
  20 #include "lib/string/util_string.h"
  21
  22 #ifdef HAVE_FCNTL_H
  23 #include <fcntl.h>
  24 #endif
  25 #ifdef HAVE_MALLOC_H
  26 #include <malloc.h>
  27 #endif
  28 #ifdef HAVE_UNISTD_H
  29 #include <unistd.h>
  30 #endif
  31
  32 #ifdef _WIN32
  33 #include <windows.h>
  34 #endif
  35 #include <string.h>
  36
  37 #if defined(HAVE_SYS_SYSCTL_H) && !defined(_WIN32) && !defined(__linux__)
  38 #include <sys/sysctl.h>
  39 #endif
  40
  41 #if defined(HW_PHYSMEM64)
  42 /* OpenBSD and NetBSD define this */
  43 #define INT64_HW_MEM HW_PHYSMEM64
  44 #elif defined(HW_MEMSIZE)
  45 /* OSX defines this one */
  46 #define INT64_HW_MEM HW_MEMSIZE
  47 #endif /* defined(HW_PHYSMEM64) || ... */
  48
  49 /**
  50  * Helper: try to detect the total system memory, and return it. On failure,
  51  * return 0.
  52  */
  53 static uint64_t
  54 get_total_system_memory_impl(void)
  55 {
  56 #if defined(__linux__)
  57   /* On linux, sysctl is deprecated. Because proc is so awesome that you
  58    * shouldn't _want_ to write portable code, I guess? */
  59   unsigned long long result=0;
  60   int fd = -1;
  61   char *s = NULL;
  62   const char *cp;
  63   size_t file_size=0;
  64   if (-1 == (fd = tor_open_cloexec("/proc/meminfo",O_RDONLY,0)))
  65     return 0;
  66   s = read_file_to_str_until_eof(fd, 65536, &file_size);
  67   if (!s)
  68     goto err;
  69   cp = find_str_at_start_of_line(s, "MemTotal:");
  70   if (!cp)
  71     goto err;
  72   /* Use the system sscanf so that space will match a wider number of space */
  73   if (sscanf(cp, "MemTotal: %llu kB\n", &result) != 1)
  74     goto err;
  75
  76   close(fd);
  77   tor_free(s);
  78   return result * 1024;
  79
  80   /* LCOV_EXCL_START Can't reach this unless proc is broken. */
  81  err:
  82   tor_free(s);
  83   close(fd);
  84   return 0;
  85   /* LCOV_EXCL_STOP */
  86 #elif defined (_WIN32)
  87   /* Windows has MEMORYSTATUSEX; pretty straightforward. */
  88   MEMORYSTATUSEX ms;
  89   memset(&ms, 0, sizeof(ms));
  90   ms.dwLength = sizeof(ms);
  91   if (! GlobalMemoryStatusEx(&ms))
  92     return 0;
  93
  94   return ms.ullTotalPhys;
  95
  96 #elif defined(HAVE_SYSCTL) && defined(INT64_HW_MEM)
  97   /* On many systems, HW_PHYSMEM is clipped to 32 bits; let's use a better
  98    * variant if we know about it. */
  99   uint64_t memsize = 0;
 100   size_t len = sizeof(memsize);
 101   int mib[2] = {CTL_HW, INT64_HW_MEM};
 102   if (sysctl(mib,2,&memsize,&len,NULL,0))
 103     return 0;
 104
 105   return memsize;
 106
 107 #elif defined(HAVE_SYSCTL) && defined(HW_PHYSMEM)
 108   /* On some systems (like FreeBSD I hope) you can use a size_t with
 109    * HW_PHYSMEM. */
 110   size_t memsize=0;
 111   size_t len = sizeof(memsize);
 112   int mib[2] = {CTL_HW, HW_PHYSMEM};
 113   if (sysctl(mib,2,&memsize,&len,NULL,0))
 114     return 0;
 115
 116   return memsize;
 117
 118 #else
 119   /* I have no clue. */
 120   return 0;
 121 #endif /* defined(__linux__) || ... */
 122 }
 123
 124 /**
 125  * Try to find out how much physical memory the system has. On success,
 126  * return 0 and set *<b>mem_out</b> to that value. On failure, return -1.
 127  */
 128 MOCK_IMPL(int,
 129 get_total_system_memory, (size_t *mem_out))
 130 {
 131   static size_t mem_cached=0;
 132   uint64_t m = get_total_system_memory_impl();
 133   if (0 == m) {
 134     /* LCOV_EXCL_START -- can't make this happen without mocking. */
 135     /* We couldn't find our memory total */
 136     if (0 == mem_cached) {
 137       /* We have no cached value either */
 138       *mem_out = 0;
 139       return -1;
 140     }
 141
 142     *mem_out = mem_cached;
 143     return 0;
 144     /* LCOV_EXCL_STOP */
 145   }
 146
 147 #if SIZE_MAX != UINT64_MAX
 148   if (m > SIZE_MAX) {
 149     /* I think this could happen if we're a 32-bit Tor running on a 64-bit
 150      * system: we could have more system memory than would fit in a
 151      * size_t. */
 152     m = SIZE_MAX;
 153   }
 154 #endif /* SIZE_MAX != UINT64_MAX */
 155
 156   *mem_out = mem_cached = (size_t) m;
 157
 158   return 0;
 159 }