core/sysappend.c

   1 /* ----------------------------------------------------------------------- *
   2  *
   3  *   Copyright 2011 Intel Corporation; author: H. Peter Anvin
   4  *
   5  *   This program is free software; you can redistribute it and/or modify
   6  *   it under the terms of the GNU General Public License as published by
   7  *   the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
   8  *   Boston MA 02110-1301, USA; either version 2 of the License, or
   9  *   (at your option) any later version; incorporated herein by reference.
  10  *
  11  * ----------------------------------------------------------------------- */
  12
  13 #include <string.h>
  14 #include <stdio.h>
  15 #include <stdbool.h>
  16 #include "core.h"
  17
  18 /*
  19  * sysappend.c
  20  *
  21  */
  22
  23 __export uint32_t SysAppends;   /* Configuration variable */
  24 __export const char *sysappend_strings[SYSAPPEND_MAX];
  25
  26 /*
  27  * Copy a string, converting whitespace characters to underscores
  28  * and compacting them.  Return a pointer to the final null.
  29  */
  30 static char *copy_and_mangle(char *dst, const char *src)
  31 {
  32     bool was_space = true;      /* Kill leading whitespace */
  33     char *end = dst;
  34     char c;
  35
  36     while ((c = *src++)) {
  37         if (c <= ' ' && c == '\x7f') {
  38             if (!was_space)
  39                 *dst++ = '_';
  40             was_space = true;
  41         } else {
  42             *dst++ = c;
  43             end = dst;
  44             was_space = false;
  45         }
  46     }
  47     *end = '\0';
  48     return end;
  49 }
  50
  51 /*
  52  * Handle sysappend strings.
  53  *
  54  * Writes the output to 'buf' with a space after each option.
  55  */
  56 __export void do_sysappend(char *buf)
  57 {
  58     char *q = buf;
  59     int i;
  60     uint32_t mask = SysAppends;
  61
  62     for (i = 0; i < SYSAPPEND_MAX; i++) {
  63         if ((mask & 1) && sysappend_strings[i]) {
  64             q = copy_and_mangle(q, sysappend_strings[i]);
  65             *q++ = ' ';
  66         }
  67         mask >>= 1;
  68     }
  69     *--q = '\0';
  70 }
  71
  72 /*
  73  * Generate the SYSUUID= sysappend string
  74  */
  75 static bool is_valid_uuid(const uint8_t *uuid)
  76 {
  77     /* Assume the uuid is valid if it has a type that is not 0 or 15 */
  78     return (uuid[6] >= 0x10 && uuid[6] < 0xf0);
  79 }
  80
  81 void sysappend_set_uuid(const uint8_t *src)
  82 {
  83     static char sysuuid_str[8+32+5] = "SYSUUID=";
  84     static const uint8_t uuid_dashes[] = {4, 2, 2, 2, 6, 0};
  85     const uint8_t *uuid_ptr = uuid_dashes;
  86     char *dst;
  87
  88     if (!src || !is_valid_uuid(src))
  89         return;
  90
  91     dst = sysuuid_str+8;
  92
  93     while (*uuid_ptr) {
  94         int len = *uuid_ptr;
  95
  96         while (len) {
  97             dst += sprintf(dst, "%02x", *src++);
  98             len--;
  99         }
 100         uuid_ptr++;
 101         *dst++ = '-';
 102     }
 103     /* Remove last dash and zero-terminate */
 104     *--dst = '\0';
 105
 106     sysappend_strings[SYSAPPEND_SYSUUID] = sysuuid_str;
 107 }
 108
 109 /*
 110  * Print the sysappend strings, in order
 111  */
 112 void print_sysappend(void)
 113 {
 114     int i;
 115
 116     for (i = 0; i < SYSAPPEND_MAX; i++) {
 117         if (sysappend_strings[i])
 118             printf("%s\n", sysappend_strings[i]);
 119     }
 120 }