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 #include "fs.h"
  18
  19 /*
  20  * sysappend.c
  21  *
  22  */
  23
  24 __export uint32_t SysAppends;   /* Configuration variable */
  25 __export const char *sysappend_strings[SYSAPPEND_MAX];
  26
  27 /*
  28  * Copy a string, converting whitespace characters to underscores
  29  * and compacting them.  Return a pointer to the final null.
  30  */
  31 static char *copy_and_mangle(char *dst, const char *src)
  32 {
  33     bool was_space = true;      /* Kill leading whitespace */
  34     char *end = dst;
  35     char c;
  36
  37     while ((c = *src++)) {
  38         if (c <= ' ' || c == '\x7f') {
  39             if (!was_space)
  40                 *dst++ = '_';
  41             was_space = true;
  42         } else {
  43             *dst++ = c;
  44             end = dst;
  45             was_space = false;
  46         }
  47     }
  48     *end = '\0';
  49     return end;
  50 }
  51
  52 /*
  53  * Handle sysappend strings.
  54  *
  55  * Writes the output to 'buf' with a space after each option.
  56  */
  57 __export void do_sysappend(char *buf)
  58 {
  59     char *q = buf;
  60     int i;
  61     uint32_t mask = SysAppends;
  62
  63     for (i = 0; i < SYSAPPEND_MAX; i++) {
  64         if ((mask & 1) && sysappend_strings[i]) {
  65             q = copy_and_mangle(q, sysappend_strings[i]);
  66             *q++ = ' ';
  67         }
  68         mask >>= 1;
  69     }
  70     *--q = '\0';
  71 }
  72
  73 /*
  74  * Generate the SYSUUID= sysappend string
  75  */
  76 static bool is_valid_uuid(const uint8_t *uuid)
  77 {
  78     /* Assume the uuid is valid if it has a type that is not 0 or 15 */
  79     return (uuid[6] >= 0x10 && uuid[6] < 0xf0);
  80 }
  81
  82 void sysappend_set_uuid(const uint8_t *src)
  83 {
  84     static char sysuuid_str[8+32+5] = "SYSUUID=";
  85     static const uint8_t uuid_dashes[] = {4, 2, 2, 2, 6, 0};
  86     const uint8_t *uuid_ptr = uuid_dashes;
  87     char *dst;
  88
  89     if (!src || !is_valid_uuid(src))
  90         return;
  91
  92     dst = sysuuid_str+8;
  93
  94     while (*uuid_ptr) {
  95         int len = *uuid_ptr;
  96
  97         while (len) {
  98             dst += sprintf(dst, "%02x", *src++);
  99             len--;
 100         }
 101         uuid_ptr++;
 102         *dst++ = '-';
 103     }
 104     /* Remove last dash and zero-terminate */
 105     *--dst = '\0';
 106
 107     sysappend_strings[SYSAPPEND_SYSUUID] = sysuuid_str;
 108 }
 109
 110 void sysappend_set_fs_uuid(void)
 111 {
 112     static char fsuuid_str[7+32+7+1] = "FSUUID=";
 113     char *uuid;
 114
 115     uuid = fs_uuid();
 116     if (!uuid)
 117         return;
 118
 119     snprintf(fsuuid_str + 7, sizeof(fsuuid_str) - 7, "%s", uuid);
 120     fsuuid_str[sizeof(fsuuid_str) - 1] = '\0';
 121     free(uuid);
 122
 123     sysappend_strings[SYSAPPEND_FSUUID] = fsuuid_str;
 124 }
 125
 126 /*
 127  * Print the sysappend strings, in order
 128  */
 129 void print_sysappend(void)
 130 {
 131     int i;
 132
 133     for (i = 0; i < SYSAPPEND_MAX; i++) {
 134         if (sysappend_strings[i])
 135             printf("%s\n", sysappend_strings[i]);
 136     }
 137 }