sys/src/boot/pc/sub.c

   1 #include <u.h>
   2 #include <a.out.h>
   3 #include "fns.h"
   4 #include "mem.h"
   5
   6 void
   7 memset(void *p, int v, int n)
   8 {
   9         uchar *d = p;
  10         while(n > 0){
  11                 *d++ = v;
  12                 n--;
  13         }
  14 }
  15
  16 void
  17 memmove(void *dst, void *src, int n)
  18 {
  19         uchar *d = dst;
  20         uchar *s = src;
  21         while(n > 0){
  22                 *d++ = *s++;
  23                 n--;
  24         }
  25 }
  26
  27 int
  28 memcmp(void *src, void *dst, int n)
  29 {
  30         uchar *d = dst;
  31         uchar *s = src;
  32         int r = 0;
  33         while((n > 0) && (r = (*d++ - *s++)) == 0)
  34                 n--;
  35         return r;
  36 }
  37
  38 int
  39 strlen(char *s)
  40 {
  41         char *p = s;
  42         while(*p)
  43                 p++;
  44         return p - s;
  45 }
  46
  47 char*
  48 strchr(char *s, int c)
  49 {
  50         for(; *s; s++)
  51                 if(*s == c)
  52                         return s;
  53         return 0;
  54 }
  55
  56 char*
  57 strrchr(char *s, int c)
  58 {
  59         char *r;
  60         r = 0;
  61         while(s = strchr(s, c))
  62                 r = s++;
  63         return r;
  64 }
  65
  66 void
  67 print(char *s)
  68 {
  69         while(*s)
  70                 putc(*s++);
  71 }
  72
  73 int
  74 readn(void *f, void *data, int len)
  75 {
  76         uchar *p, *e;
  77
  78         p = data;
  79         e = p + len;
  80         while(p < e){
  81                 if((len = read(f, p, e - p)) <= 0)
  82                         break;
  83                 p += len;
  84         }
  85         return p - (uchar*)data;
  86 }
  87
  88 static int
  89 readline(void *f, char buf[64])
  90 {
  91         static char white[] = "\t ";
  92         char *p;
  93
  94         p = buf;
  95         do{
  96                 if(!f)
  97                         putc('>');
  98                 while(p < buf + 64-1){
  99                         if(!f){
 100                                 putc(*p = getc());
 101                                 if(*p == '\r')
 102                                         putc('\n');
 103                                 else if(*p == 0x08 && p > buf){
 104                                         p--;
 105                                         continue;
 106                                 }
 107                         }else if(read(f, p, 1) <= 0)
 108                                 return 0;
 109                         if(p == buf && strchr(white, *p))
 110                                 continue;
 111                         if(strchr(crnl, *p))
 112                                 break;
 113                         p++;
 114                 }
 115                 while(p > buf && strchr(white, p[-1]))
 116                         p--;
 117         }while(p == buf);
 118         *p = 0;
 119         return p - buf;
 120 }
 121
 122 char*
 123 configure(void *f, char *path)
 124 {
 125         char line[64], *p, *kern;
 126         int inblock, n;
 127
 128 Clear:
 129         kern = 0;
 130         inblock = 0;
 131         p = (char*)((CONFADDR + 64) & ~0xF0000000UL);
 132 Loop:
 133         while((n = readline(f, line)) > 0){
 134                 if(*line == 0 || strchr("#;=", *line))
 135                         continue;
 136                 if(*line == '['){
 137                         inblock = memcmp("[common]", line, 8);
 138                         continue;
 139                 }
 140                 if(memcmp("clear", line, 6) == 0){
 141                         print("ok\r\n");
 142                         goto Clear;
 143                 }
 144                 if(memcmp("boot", line, 5) == 0)
 145                         break;
 146                 if(inblock || !strrchr(line, '='))
 147                         continue;
 148                 print(line); print(crnl);
 149                 if(memcmp("bootfile=", line, 9) == 0)
 150                         memmove(kern = path, line+9, 1 + n-9);
 151                 memmove(p, line, n); p += n;
 152                 *p++ = '\n';
 153         }
 154         *p = 0;
 155         if(f){
 156                 close(f);
 157                 f = 0;
 158         }
 159         if(!kern){
 160                 print("no bootfile\r\n");
 161                 goto Loop;
 162         }
 163         for(n=0; n<10000; n++)
 164                 if(gotc())
 165                         goto Loop;
 166         if(p = strrchr(kern, '!'))
 167                 kern = p+1;
 168         return kern;
 169 }
 170
 171
 172 static ushort
 173 beswab(ushort s)
 174 {
 175         uchar *p;
 176
 177         p = (uchar*)&s;
 178         return (p[0]<<8) | p[1];
 179 }
 180
 181 static ulong
 182 beswal(ulong l)
 183 {
 184         uchar *p;
 185
 186         p = (uchar*)&l;
 187         return (p[0]<<24) | (p[1]<<16) | (p[2]<<8) | p[3];
 188 }
 189
 190 char*
 191 bootkern(void *f)
 192 {
 193         uchar *e, *d;
 194         Exec ex;
 195         int n;
 196
 197         a20();
 198         if(readn(f, &ex, sizeof(ex)) != sizeof(ex))
 199                 return "bad header";
 200         if(beswal(ex.magic) != I_MAGIC)
 201                 return "bad magic";
 202         e = (uchar*)(beswal(ex.entry) & ~0xF0000000UL);
 203         n = beswal(ex.text);
 204         if(readn(f, e, n) != n)
 205                 goto Error;
 206         d = (uchar*)(((ulong)e + n + 0xFFF) & ~0xFFFUL);
 207         n = beswal(ex.data);
 208         if(readn(f, d, n) != n)
 209                 goto Error;
 210         close(f);
 211         jump(e);
 212 Error:
 213         return "i/o error";
 214 }