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
  22         if(d < s){
  23                 while(n > 0){
  24                         *d++ = *s++;
  25                         n--;
  26                 }
  27         } if(d > s){
  28                 s += n;
  29                 d += n;
  30                 while(n > 0){
  31                         *--d = *--s;
  32                         n--;
  33                 }
  34         }
  35 }
  36
  37 int
  38 memcmp(void *src, void *dst, int n)
  39 {
  40         uchar *d = dst;
  41         uchar *s = src;
  42         int r = 0;
  43         while((n > 0) && (r = (*d++ - *s++)) == 0)
  44                 n--;
  45         return r;
  46 }
  47
  48 int
  49 strlen(char *s)
  50 {
  51         char *p = s;
  52         while(*p)
  53                 p++;
  54         return p - s;
  55 }
  56
  57 char*
  58 strchr(char *s, int c)
  59 {
  60         for(; *s; s++)
  61                 if(*s == c)
  62                         return s;
  63         return 0;
  64 }
  65
  66 char*
  67 strrchr(char *s, int c)
  68 {
  69         char *r;
  70         r = 0;
  71         while(s = strchr(s, c))
  72                 r = s++;
  73         return r;
  74 }
  75
  76 void
  77 print(char *s)
  78 {
  79         while(*s)
  80                 putc(*s++);
  81 }
  82
  83 int
  84 readn(void *f, void *data, int len)
  85 {
  86         uchar *p, *e;
  87
  88         p = data;
  89         e = p + len;
  90         while(p < e){
  91                 if((len = read(f, p, e - p)) <= 0)
  92                         break;
  93                 p += len;
  94         }
  95         return p - (uchar*)data;
  96 }
  97
  98 static int
  99 readline(void *f, char buf[64])
 100 {
 101         static char white[] = "\t ";
 102         char *p;
 103
 104         p = buf;
 105         do{
 106                 if(!f)
 107                         putc('>');
 108                 while(p < buf + 64-1){
 109                         if(!f){
 110                                 putc(*p = getc());
 111                                 if(*p == '\r')
 112                                         putc('\n');
 113                                 else if(*p == 0x08 && p > buf){
 114                                         p--;
 115                                         continue;
 116                                 }
 117                         }else if(read(f, p, 1) <= 0)
 118                                 return 0;
 119                         if(p == buf && strchr(white, *p))
 120                                 continue;
 121                         if(strchr(crnl, *p))
 122                                 break;
 123                         p++;
 124                 }
 125                 while(p > buf && strchr(white, p[-1]))
 126                         p--;
 127         }while(p == buf);
 128         *p = 0;
 129         return p - buf;
 130 }
 131
 132 char*
 133 configure(void *f, char *path)
 134 {
 135         char line[64], *p, *kern;
 136         int inblock, n;
 137
 138 Clear:
 139         kern = 0;
 140         inblock = 0;
 141         p = (char*)(CONFADDR & ~0xF0000000UL);
 142         memset(p, 0, 0xE00);
 143         p += 64;
 144 Loop:
 145         while((n = readline(f, line)) > 0){
 146                 if(*line == 0 || strchr("#;=", *line))
 147                         continue;
 148                 if(*line == '['){
 149                         inblock = memcmp("[common]", line, 8);
 150                         continue;
 151                 }
 152                 if(memcmp("clear", line, 6) == 0){
 153                         print("ok\r\n");
 154                         goto Clear;
 155                 }
 156                 if(memcmp("boot", line, 5) == 0)
 157                         break;
 158                 if(inblock || !strrchr(line, '='))
 159                         continue;
 160                 print(line); print(crnl);
 161                 if(memcmp("bootfile=", line, 9) == 0)
 162                         memmove(kern = path, line+9, 1 + n-9);
 163                 memmove(p, line, n); p += n;
 164                 *p++ = '\n';
 165         }
 166         *p = 0;
 167         if(f){
 168                 close(f);
 169                 f = 0;
 170         }
 171         if(!kern){
 172                 print("no bootfile\r\n");
 173                 goto Loop;
 174         }
 175         for(n=0; n<10000; n++)
 176                 if(gotc())
 177                         goto Loop;
 178         if(p = strrchr(kern, '!'))
 179                 kern = p+1;
 180         return kern;
 181 }
 182
 183
 184 static ushort
 185 beswab(ushort s)
 186 {
 187         uchar *p;
 188
 189         p = (uchar*)&s;
 190         return (p[0]<<8) | p[1];
 191 }
 192
 193 static ulong
 194 beswal(ulong l)
 195 {
 196         uchar *p;
 197
 198         p = (uchar*)&l;
 199         return (p[0]<<24) | (p[1]<<16) | (p[2]<<8) | p[3];
 200 }
 201
 202 char*
 203 bootkern(void *f)
 204 {
 205         uchar *e, *d, *t;
 206         ulong n;
 207         Exec ex;
 208
 209         a20();
 210         if(readn(f, &ex, sizeof(ex)) != sizeof(ex))
 211                 return "bad header";
 212         if(beswal(ex.magic) != I_MAGIC)
 213                 return "bad magic";
 214
 215         e = (uchar*)(beswal(ex.entry) & ~0xF0000000UL);
 216         t = e;
 217         n = beswal(ex.text);
 218         if(readn(f, t, n) != n)
 219                 goto Error;
 220         d = (uchar*)PGROUND((ulong)t + n);
 221         n = beswal(ex.data);
 222         if(readn(f, d, n) != n)
 223                 goto Error;
 224         close(f);
 225         unload();
 226         jump(e);
 227 Error:
 228         return "i/o error";
 229 }