inmates/lib/cmdline.c

   1 /*
   2  * Jailhouse, a Linux-based partitioning hypervisor
   3  *
   4  * Copyright (c) Siemens AG, 2016
   5  *
   6  * Authors:
   7  *  Jan Kiszka <jan.kiszka@siemens.com>
   8  *
   9  * This work is licensed under the terms of the GNU GPL, version 2.  See
  10  * the COPYING file in the top-level directory.
  11  */
  12
  13 #include <inmate.h>
  14
  15 extern const char cmdline[];
  16
  17 static bool get_param(const char *param, char *value_buffer,
  18                       unsigned long buffer_size)
  19 {
  20         unsigned long param_len = strlen(param);
  21         const char *p = cmdline;
  22
  23         while (1) {
  24                 /* read over leading blanks */
  25                 while (*p == ' ')
  26                         p++;
  27
  28                 if (strncmp(p, param, param_len) == 0) {
  29                         p += param_len;
  30
  31                         /* check for boolean parameter */
  32                         if ((buffer_size == 0 && (*p == ' ' || *p == 0)))
  33                                 return true;
  34
  35                         /* extract parameter value */
  36                         if (*p == '=') {
  37                                 p++;
  38                                 while (buffer_size > 1) {
  39                                         if (*p == ' ' || *p == 0)
  40                                                 break;
  41                                         *value_buffer++ = *p++;
  42                                         buffer_size--;
  43                                 }
  44                                 if (buffer_size > 0)
  45                                         *value_buffer = 0;
  46                                 return true;
  47                         }
  48                 }
  49
  50                 /* search for end of this parameter */
  51                 while (*p != ' ') {
  52                         if (*p == 0)
  53                                 return false;
  54                         p++;
  55                 }
  56         }
  57 }
  58
  59 const char *cmdline_parse_str(const char *param, char *value_buffer,
  60                               unsigned long buffer_size,
  61                               const char *default_value)
  62 {
  63         if (get_param(param, value_buffer, buffer_size))
  64                 return value_buffer;
  65         else
  66                 return default_value;
  67 }
  68
  69 long long cmdline_parse_int(const char *param, long long default_value)
  70 {
  71         char value_buffer[32];
  72         char *p = value_buffer;
  73         bool negative = false;
  74         long long value = 0;
  75
  76         if (!get_param(param, value_buffer, sizeof(value_buffer)))
  77                 return default_value;
  78
  79         if (strncmp(p, "0x", 2) == 0) {
  80                 p += 2;
  81                 do {
  82                         if (*p >= '0' && *p <= '9')
  83                                 value = (value << 4) + *p - '0';
  84                         else if (*p >= 'A' && *p <= 'F')
  85                                 value = (value << 4) + *p - 'A' + 10;
  86                         else if (*p >= 'a' && *p <= 'f')
  87                                 value = (value << 4) + *p - 'a' + 10;
  88                         else
  89                                 return default_value;
  90                         p++;
  91                 } while (*p != 0);
  92         } else {
  93                 if (*p == '-' || *p == '+')
  94                         negative = (*p++ == '-');
  95
  96                 do {
  97                         if (*p >= '0' && *p <= '9')
  98                                 value = (value * 10) + *p - '0';
  99                         else
 100                                 return default_value;
 101                         p++;
 102                 } while (*p != 0);
 103         }
 104
 105         return negative ? -value : value;
 106 }
 107
 108 bool cmdline_parse_bool(const char *param)
 109 {
 110         return get_param(param, NULL, 0);
 111 }