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                         if (*p == 0)
  27                                 return false;
  28                         p++;
  29                 }
  30
  31                 if (strncmp(p, param, param_len) == 0) {
  32                         p += param_len;
  33
  34                         /* check for boolean parameter */
  35                         if ((buffer_size == 0 && (*p == ' ' || *p == 0)))
  36                                 return true;
  37
  38                         /* extract parameter value */
  39                         if (*p == '=') {
  40                                 p++;
  41                                 while (buffer_size > 1) {
  42                                         if (*p == ' ' || *p == 0)
  43                                                 break;
  44                                         *value_buffer++ = *p++;
  45                                         buffer_size--;
  46                                 }
  47                                 if (buffer_size > 0)
  48                                         *value_buffer = 0;
  49                                 return true;
  50                         }
  51                 }
  52
  53                 /* search for end of this parameter */
  54                 while (*p != ' ') {
  55                         if (*p == 0)
  56                                 return false;
  57                         p++;
  58                 }
  59         }
  60 }
  61
  62 const char *cmdline_parse_str(const char *param, char *value_buffer,
  63                               unsigned long buffer_size,
  64                               const char *default_value)
  65 {
  66         if (get_param(param, value_buffer, buffer_size))
  67                 return value_buffer;
  68         else
  69                 return default_value;
  70 }
  71
  72 long long cmdline_parse_int(const char *param, long long default_value)
  73 {
  74         char value_buffer[32];
  75         char *p = value_buffer;
  76         bool negative = false;
  77         long long value = 0;
  78
  79         if (!get_param(param, value_buffer, sizeof(value_buffer)))
  80                 return default_value;
  81
  82         if (strncmp(p, "0x", 2) == 0) {
  83                 p += 2;
  84                 do {
  85                         if (*p >= '0' && *p <= '9')
  86                                 value = (value << 4) + *p - '0';
  87                         else if (*p >= 'A' && *p <= 'F')
  88                                 value = (value << 4) + *p - 'A';
  89                         else if (*p >= 'a' && *p <= 'f')
  90                                 value = (value << 4) + *p - 'a';
  91                         else
  92                                 return default_value;
  93                         p++;
  94                 } while (*p != 0);
  95         } else {
  96                 if (*p == '-' || *p == '+')
  97                         negative = (*p++ == '-');
  98
  99                 do {
 100                         if (*p >= '0' && *p <= '9')
 101                                 value = (value * 10) + *p - '0';
 102                         else
 103                                 return default_value;
 104                         p++;
 105                 } while (*p != 0);
 106         }
 107
 108         return negative ? -value : value;
 109 }
 110
 111 bool cmdline_parse_bool(const char *param)
 112 {
 113         return get_param(param, NULL, 0);
 114 }