linux_emul_base/tls.c

   1 #include <u.h>
   2 #include <libc.h>
   3 #include <ureg.h>
   4 #include "dat.h"
   5 #include "fns.h"
   6 #include "linux.h"
   7
   8 enum {
   9         Index,
  10         Type,
  11         Flags,
  12         DPL,
  13         Base,
  14         Limit,
  15         Nfields,
  16 };
  17
  18 static int
  19 descempty(struct linux_user_desc *info)
  20 {
  21         return info->base_addr==0 && info->limit==0 &&
  22                 info->contents==0 && info->read_exec_only==1 &&
  23                 info->seg_32bit==0 && info->limit_in_pages==0 &&
  24                 info->seg_not_present==1 && info->useable==0;
  25 }
  26
  27 int sys_set_thread_area(void *pinfo)
  28 {
  29         struct linux_user_desc *info = pinfo;
  30         char buf[1024];
  31         char *p, *e, *f[Nfields];
  32         int n, fd, idx, err;
  33
  34         trace("sys_set_thread_area(%p)", pinfo);
  35
  36         err = -ENOSYS;
  37         if((fd = open("/dev/gdt", ORDWR)) < 0)
  38                 goto out;
  39
  40         idx = info->entry_number;
  41         if(idx == -1){
  42                 err = -ESRCH;
  43                 if((n = read(fd, buf, sizeof(buf)-1)) <= 0)
  44                         goto out;
  45                 buf[n] = 0;
  46                 p = buf;
  47                 while(e = strchr(p, '\n')){
  48                         *e = 0;
  49                         if(getfields(p, f, nelem(f), 1, " ") != nelem(f))
  50                                 goto out;
  51                         idx = strtoul(f[Index], nil, 16);
  52                         if(idx >= 8*sizeof(current->tlsmask))
  53                                 break;
  54                         if((current->tlsmask & (1<<idx)) == 0)
  55                                 goto found;
  56                         p = e+1;
  57                 }
  58                 goto out;
  59         }
  60
  61 found:
  62         err = -EINVAL;
  63         if(idx < 0 || idx >= 8*sizeof(current->tlsmask))
  64                 goto out;
  65
  66         buf[0] = 0;
  67         if(!info->seg_not_present)
  68                 strcat(buf, "P");
  69         if(info->limit_in_pages)
  70                 strcat(buf, "G");
  71         if(info->useable)
  72                 strcat(buf, "U");
  73         if(info->contents & 2){
  74                 /* code segment */
  75                 if(info->contents & 1)
  76                         strcat(buf, "C");
  77                 if(info->seg_32bit)
  78                         strcat(buf, "D");
  79                 if(!info->read_exec_only)
  80                         strcat(buf, "R");
  81                 if(buf[0] == 0)
  82                         strcat(buf, "-");
  83
  84                 if(fprint(fd, "%x code %s 3 %lux %lux\n",
  85                         idx, buf, (ulong)info->base_addr, (ulong)info->limit) < 0)
  86                         goto out;
  87         } else {
  88                 /* data segment */
  89                 if(info->contents & 1)
  90                         strcat(buf, "E");
  91                 if(info->seg_32bit)
  92                         strcat(buf, "B");
  93                 if(!info->read_exec_only)
  94                         strcat(buf, "W");
  95                 if(buf[0] == 0)
  96                         strcat(buf, "-");
  97
  98                 if(fprint(fd, "%x data %s 3 %lux %lux\n",
  99                         idx, buf, (ulong)info->base_addr, (ulong)info->limit) < 0)
 100                         goto out;
 101         }
 102
 103         err = 0;
 104         info->entry_number = idx;
 105         if(!descempty(info)){
 106                 current->tlsmask |= 1<<idx;
 107         } else {
 108                 current->tlsmask &= ~(1<<idx);
 109         }
 110
 111 out:
 112         if(fd >= 0)
 113                 close(fd);
 114         return err;
 115 }
 116
 117 int sys_get_thread_area(void *pinfo)
 118 {
 119         struct linux_user_desc *info = pinfo;
 120         int err, n, fd, idx;
 121         char buf[1024];
 122         char *p, *e, *f[Nfields];
 123
 124         trace("sys_get_thread_area(%p)", pinfo);
 125
 126         err = -ENOSYS;
 127         if((fd = open("/dev/gdt", OREAD)) < 0)
 128                 goto out;
 129
 130         err = -EINVAL;
 131         if((n = read(fd, buf, sizeof(buf)-1)) <= 0)
 132                 goto out;
 133         buf[n] = 0;
 134         p = buf;
 135         while(e = strchr(p, '\n')){
 136                 *e = 0;
 137                 if(getfields(p, f, nelem(f), 1, " ") != nelem(f))
 138                         goto out;
 139                 idx = strtoul(f[Index], nil, 16);
 140                 if(idx >= 8*sizeof(current->tlsmask))
 141                         break;
 142                 if(idx == info->entry_number)
 143                         goto found;
 144                 p = e+1;
 145         }
 146         goto out;
 147
 148 found:
 149         info->contents = 0;
 150         if(strcmp(f[Type], "code") == 0)
 151                 info->contents |= 2;
 152         info->seg_not_present = 1;
 153         info->limit_in_pages = 0;
 154         info->seg_32bit = 0;
 155         info->read_exec_only = 1;
 156         info->useable = 0;
 157         for(p = f[Flags]; *p; p++){
 158                 switch(*p){
 159                 case 'P':
 160                         info->seg_not_present = 0;
 161                         break;
 162                 case 'G':
 163                         info->limit_in_pages = 1;
 164                         break;
 165                 case 'B':
 166                 case 'D':
 167                         info->seg_32bit = 1;
 168                         break;
 169                 case 'W':
 170                 case 'R':
 171                         info->read_exec_only = 0;
 172                         break;
 173                 case 'U':
 174                         info->useable = 1;
 175                         break;
 176                 case 'E':
 177                 case 'C':
 178                         info->contents |= 1;
 179                         break;
 180                 }
 181         }
 182
 183         info->base_addr = strtoul(f[Base], nil, 16);
 184         info->limit = strtoul(f[Limit], nil, 16);
 185
 186         err = 0;
 187
 188 out:
 189         if(fd >= 0)
 190                 close(fd);
 191         return err;
 192 }
 193
 194 static void
 195 cleardesc(struct linux_user_desc *info)
 196 {
 197         info->base_addr=0;
 198         info->limit=0;
 199         info->contents=0;
 200         info->read_exec_only=1;
 201         info->seg_32bit=0;
 202         info->limit_in_pages=0;
 203         info->seg_not_present=1;
 204         info->useable=0;
 205 }
 206
 207 void inittls(void)
 208 {
 209         struct linux_user_desc info;
 210         int i;
 211
 212         for(i=0; i<8*sizeof(current->tlsmask); i++){
 213                 if((current->tlsmask & (1 << i)) == 0)
 214                         continue;
 215                 cleardesc(&info);
 216                 info.entry_number = i;
 217                 sys_set_thread_area(&info);
 218         }
 219         current->tlsmask = 0;
 220 }
 221
 222 void clonetls(Uproc *new)
 223 {
 224         new->tlsmask = current->tlsmask;
 225 }
 226
 227 int sys_modify_ldt(int func, void *data, int count)
 228 {
 229         trace("sys_modify_ldt(%d, %p, %x)", func, data, count);
 230
 231         return -ENOSYS;
 232 }