Kernel/syscalls.c

   1 /*
   2  * AcessOS Microkernel Version
   3  * syscalls.c
   4  */
   5 #define DEBUG   0
   6
   7 #include <acess.h>
   8 #include <syscalls.h>
   9 #include <proc.h>
  10 #include <hal_proc.h>
  11 #include <errno.h>
  12 #include <threads.h>
  13
  14 #define CHECK_NUM_NULLOK(v,size)        \
  15         if((v)&&!Syscall_Valid((size),(v))){ret=-1;err=-EINVAL;break;}
  16 #define CHECK_STR_NULLOK(v)     \
  17         if((v)&&!Syscall_ValidString((v))){ret=-1;err=-EINVAL;break;}
  18 #define CHECK_NUM_NONULL(v,size)        \
  19         if(!(v)||!Syscall_Valid((size),(v))){ret=-1;err=-EINVAL;break;}
  20 #define CHECK_STR_NONULL(v)     \
  21         if(!(v)||!Syscall_ValidString((v))){ret=-1;err=-EINVAL;break;}
  22
  23 // === IMPORTS ===
  24 extern int      Proc_Execve(char *File, char **ArgV, char **EnvP);
  25 extern Uint     Binary_Load(const char *file, Uint *entryPoint);
  26
  27 // === PROTOTYPES ===
  28 void    SyscallHandler(tSyscallRegs *Regs);
  29  int    Syscall_ValidString(const char *Addr);
  30  int    Syscall_Valid(int Size, const void *Addr);
  31
  32 // === CODE ===
  33 // TODO: Do sanity checking on arguments, ATM the user can really fuck with the kernel
  34 void SyscallHandler(tSyscallRegs *Regs)
  35 {
  36         Uint64  ret = 0;
  37         Uint    err = -EOK;
  38          int    callNum = Regs->Num;
  39
  40         #if DEBUG < 2
  41         if(callNum != SYS_READ && callNum != SYS_WRITE) {
  42         #endif
  43         ENTER("iThread iNum", Threads_GetTID(), callNum);
  44         if(callNum < NUM_SYSCALLS)
  45                 LOG("Syscall %s", cSYSCALL_NAMES[callNum]);
  46         LOG("Arg1: 0x%x, Arg2: 0x%x, Arg3: 0x%x, Arg4: 0x%x", Regs->Arg1, Regs->Arg2, Regs->Arg3, Regs->Arg4);
  47         #if DEBUG < 2
  48         }
  49         #endif
  50
  51         switch(Regs->Num)
  52         {
  53         // -- Exit the current thread
  54         case SYS_EXIT:  Threads_Exit(0, Regs->Arg1);    break;
  55
  56         // -- Put the current thread to sleep
  57         case SYS_SLEEP: Threads_Sleep();        break;
  58
  59         // -- Yield current timeslice
  60         case SYS_YIELD: Threads_Yield();        break;
  61
  62         // -- Set Error Handler
  63         case SYS_SETFAULTHANDLER:
  64                 Threads_SetFaultHandler(Regs->Arg1);
  65                 break;
  66
  67         // -- Clone the current thread
  68         case SYS_CLONE:
  69                 // Call clone system call
  70                 ret = Proc_Clone(Regs->Arg1);
  71                 break;
  72
  73         // -- Send a signal
  74         case SYS_KILL:
  75                 err = -ENOSYS;
  76                 ret = -1;
  77                 break;
  78
  79         // -- Wait for a thread
  80         case SYS_WAITTID:
  81                 // Sanity Check (Status can be NULL)
  82                 CHECK_NUM_NULLOK( (int*)Regs->Arg2, sizeof(int) );
  83                 // TID, *Status
  84                 ret = Threads_WaitTID(Regs->Arg1, (int*)Regs->Arg2);
  85                 break;
  86
  87         // -- Get the physical address of a page
  88         case SYS_GETPHYS:
  89                 ret = MM_GetPhysAddr(Regs->Arg1);
  90                 break;
  91
  92         // -- Map an address
  93         case SYS_MAP:   MM_Map(Regs->Arg1, Regs->Arg2); break;
  94
  95         // -- Allocate an address
  96         case SYS_ALLOCATE:      ret = MM_Allocate(Regs->Arg1);  break;
  97
  98         // -- Unmap an address
  99         case SYS_UNMAP:         MM_Deallocate(Regs->Arg1);      break;
 100
 101         // -- Get Thread/Process IDs
 102         case SYS_GETTID:        ret = Threads_GetTID(); break;
 103         case SYS_GETPID:        ret = Threads_GetPID(); break;
 104
 105         // -- Get User/Group IDs
 106         case SYS_GETUID:        ret = Threads_GetUID(); break;
 107         case SYS_GETGID:        ret = Threads_GetGID(); break;
 108
 109         // -- Set User/Group IDs
 110         case SYS_SETUID:        ret = Threads_SetUID(&err, Regs->Arg1); break;
 111         case SYS_SETGID:        ret = Threads_SetGID(&err, Regs->Arg1); break;
 112
 113         // -- Send Message
 114         case SYS_SENDMSG:
 115                 CHECK_NUM_NONULL( (void*)Regs->Arg3, Regs->Arg2 );
 116                 // Destination, Size, *Data
 117                 ret = Proc_SendMessage(&err, Regs->Arg1, Regs->Arg2, (void*)Regs->Arg3);
 118                 break;
 119         // -- Check for messages
 120         case SYS_GETMSG:
 121                 CHECK_NUM_NULLOK( (Uint*)Regs->Arg1, sizeof(Uint) );
 122                 // NOTE: Can't do range checking as we don't know the size
 123                 // - Should be done by Proc_GetMessage
 124                 if( Regs->Arg2 && Regs->Arg2 != -1 && !MM_IsUser(Regs->Arg2) ) {
 125                         err = -EINVAL;  ret = -1;       break;
 126                 }
 127                 // *Source, *Data
 128                 ret = Proc_GetMessage(&err, (Uint*)Regs->Arg1, (void*)Regs->Arg2);
 129                 break;
 130
 131         // -- Get the current timestamp
 132         case SYS_GETTIME:
 133                 ret = now();
 134                 break;
 135
 136         // -- Set the thread's name
 137         case SYS_SETNAME:
 138                 CHECK_STR_NONULL( (char*) Regs->Arg1);
 139                 Threads_SetName( (char*)Regs->Arg1 );
 140                 break;
 141
 142         // ---
 143         // Binary Control
 144         // ---
 145         // -- Replace the current process with another
 146         case SYS_EXECVE:
 147                 CHECK_STR_NONULL((char*)Regs->Arg1);
 148                 // Check the argument arrays
 149                 {
 150                          int    i;
 151                         char    **tmp = (char**)Regs->Arg2;
 152                         // Check ArgV (traverse array checking all string pointers)
 153                         CHECK_NUM_NONULL( tmp, sizeof(char**) );
 154                         //Log("tmp = %p", tmp);
 155                         for(i=0;tmp[i];i++) {
 156                                 CHECK_NUM_NONULL( &tmp[i], sizeof(char*) );
 157                                 CHECK_STR_NONULL( tmp[i] );
 158                         }
 159                         // Check EnvP also
 160                         // - EnvP can be NULL
 161                         if( Regs->Arg3 )
 162                         {
 163                                 tmp = (char**)Regs->Arg3;
 164                                 //Log("tmp = %p", tmp);
 165                                 for(i=0;tmp[i];i++) {
 166                                         CHECK_NUM_NULLOK( &tmp[i], sizeof(char*) );
 167                                         CHECK_STR_NONULL( tmp[i] );
 168                                 }
 169                         }
 170                 }
 171                 LEAVE('s', "Assuming 0");
 172                 // Path, **Argv, **Envp
 173                 ret = Proc_Execve( (char*)Regs->Arg1, (char**)Regs->Arg2, (char**)Regs->Arg3 );
 174                 break;
 175         // -- Load a binary into the current process
 176         case SYS_LOADBIN:
 177                 if( !Syscall_ValidString( (char*) Regs->Arg1)
 178                 ||  !Syscall_Valid(sizeof(Uint), (Uint*)Regs->Arg2) ) {
 179                         err = -EINVAL;
 180                         ret = 0;
 181                         break;
 182                 }
 183                 // Path, *Entrypoint
 184                 ret = Binary_Load((char*)Regs->Arg1, (Uint*)Regs->Arg2);
 185                 break;
 186
 187         // ---
 188         // Virtual Filesystem
 189         // ---
 190         case SYS_OPEN:
 191                 CHECK_STR_NONULL( (char*)Regs->Arg1 );
 192                 LOG("VFS_Open(\"%s\", 0x%x)", (char*)Regs->Arg1, Regs->Arg2 | VFS_OPENFLAG_USER);
 193                 ret = VFS_Open((char*)Regs->Arg1, Regs->Arg2 | VFS_OPENFLAG_USER);
 194                 break;
 195
 196         case SYS_CLOSE:
 197                 LOG("VFS_Close(%i)", Regs->Arg1);
 198                 VFS_Close( Regs->Arg1 );
 199                 break;
 200
 201         case SYS_SEEK:
 202                 #if BITS == 64
 203                 ret = VFS_Seek( Regs->Arg1, Regs->Arg2, Regs->Arg3 );
 204                 #else
 205                 ret = VFS_Seek( Regs->Arg1, Regs->Arg2|(((Uint64)Regs->Arg3)<<32), Regs->Arg4 );
 206                 #endif
 207                 break;
 208
 209         case SYS_TELL:
 210                 ret = VFS_Tell( Regs->Arg1 );
 211                 break;
 212
 213         case SYS_WRITE:
 214                 CHECK_NUM_NONULL( (void*)Regs->Arg2, Regs->Arg3 );
 215                 ret = VFS_Write( Regs->Arg1, Regs->Arg3, (void*)Regs->Arg2 );
 216                 break;
 217
 218         case SYS_READ:
 219                 CHECK_NUM_NONULL( (void*)Regs->Arg2, Regs->Arg3 );
 220                 ret = VFS_Read( Regs->Arg1, Regs->Arg3, (void*)Regs->Arg2 );
 221                 break;
 222
 223         case SYS_FINFO:
 224                 CHECK_NUM_NONULL( (void*)Regs->Arg2, sizeof(tFInfo) + Regs->Arg3*sizeof(tVFS_ACL) );
 225                 // FP, Dest, MaxACLs
 226                 ret = VFS_FInfo( Regs->Arg1, (void*)Regs->Arg2, Regs->Arg3 );
 227                 break;
 228
 229         // Get ACL Value
 230         case SYS_GETACL:
 231                 CHECK_NUM_NONULL( (void*)Regs->Arg2, sizeof(tVFS_ACL) );
 232                 ret = VFS_GetACL( Regs->Arg1, (void*)Regs->Arg2 );
 233                 break;
 234
 235         // Read Directory
 236         case SYS_READDIR:
 237                 // TODO: What if the filename is longer?
 238                 // Maybe force it to be a 256 byte buffer
 239                 CHECK_NUM_NONULL( (void*)Regs->Arg2, 256 );
 240                 ret = VFS_ReadDir( Regs->Arg1, (void*)Regs->Arg2 );
 241                 break;
 242
 243         // Open a file that is a entry in an open directory
 244         case SYS_OPENCHILD:
 245                 CHECK_STR_NONULL( (char*)Regs->Arg2 );
 246                 ret = VFS_OpenChild( Regs->Arg1, (char*)Regs->Arg2, Regs->Arg3);
 247                 break;
 248
 249         // Change Directory
 250         case SYS_CHDIR:
 251                 CHECK_STR_NONULL( (const char*)Regs->Arg1 );
 252                 ret = VFS_ChDir( (const char*)Regs->Arg1 );
 253                 break;
 254
 255         // IO Control
 256         case SYS_IOCTL:
 257                 // All sanity checking should be done by the driver
 258                 if( Regs->Arg3 && !MM_IsUser(Regs->Arg3) ) {
 259                         err = -EINVAL;  ret = -1;       break;
 260                 }
 261                 ret = VFS_IOCtl( Regs->Arg1, Regs->Arg2, (void*)Regs->Arg3 );
 262                 break;
 263
 264         // Mount a filesystem
 265         case SYS_MOUNT:
 266                 // Only root can mount filesystems
 267                 if(Threads_GetUID() != 0) {
 268                         err = -EACCES;
 269                         ret = -1;
 270                         break;
 271                 }
 272                 // Sanity check the paths
 273                 if(!Syscall_ValidString((char*)Regs->Arg1)
 274                 || !Syscall_ValidString((char*)Regs->Arg2)
 275                 || !Syscall_ValidString((char*)Regs->Arg3)
 276                 || !Syscall_ValidString((char*)Regs->Arg4) ) {
 277                         err = -EINVAL;
 278                         ret = -1;
 279                         break;
 280                 }
 281                 ret = VFS_Mount(
 282                         (char*)Regs->Arg1,      // Device
 283                         (char*)Regs->Arg2,      // Mount point
 284                         (char*)Regs->Arg3,      // Filesystem
 285                         (char*)Regs->Arg4       // Options
 286                         );
 287                 break;
 288
 289         // Wait on a set of handles
 290         case SYS_SELECT:
 291                 // Sanity checks
 292                 if( (Regs->Arg2 && !Syscall_Valid(sizeof(fd_set), (void*)Regs->Arg2))
 293                  || (Regs->Arg3 && !Syscall_Valid(sizeof(fd_set), (void*)Regs->Arg3))
 294                  || (Regs->Arg4 && !Syscall_Valid(sizeof(fd_set), (void*)Regs->Arg4))
 295                  || (Regs->Arg5 && !Syscall_Valid(sizeof(tTime), (void*)Regs->Arg5)) )
 296                 {
 297                         err = -EINVAL;
 298                         ret = -1;
 299                         break;
 300                 }
 301                 // Perform the call
 302                 ret = VFS_Select(
 303                         Regs->Arg1,     // Max handle
 304                         (fd_set *)Regs->Arg2,   // Read
 305                         (fd_set *)Regs->Arg3,   // Write
 306                         (fd_set *)Regs->Arg4,   // Errors
 307                         (tTime *)Regs->Arg5,    // Timeout
 308                         0       // User handles
 309                         );
 310                 break;
 311
 312         // -- Debug
 313         //#if DEBUG_BUILD
 314         case SYS_DEBUG:
 315                 CHECK_STR_NONULL( (char*)Regs->Arg1 );
 316                 LogF("Log: [%i] ", Threads_GetTID());
 317                 LogF((const char*)Regs->Arg1,
 318                         Regs->Arg2, Regs->Arg3, Regs->Arg4, Regs->Arg5, Regs->Arg6);
 319                 LogF("\r\n");
 320                 break;
 321         //#endif
 322
 323         // -- Default (Return Error)
 324         default:
 325                 Log_Warning("Syscalls", "Unknown System Call %i", Regs->Num);
 326                 if(Regs->Num < NUM_SYSCALLS)
 327                         Log_Warning("Syscall", " named '%s'", cSYSCALL_NAMES[Regs->Num]);
 328                 err = -ENOSYS;
 329                 ret = -1;
 330                 break;
 331         }
 332
 333         if(err == 0)    err = errno;
 334
 335         if(err != 0) {
 336                 LOG("ID: %i, Return errno = %i", Regs->Num, err);
 337         }
 338
 339         #if BITS < 64
 340         Regs->Return = ret&0xFFFFFFFF;
 341         Regs->RetHi = ret >> 32;
 342         #else
 343         Regs->Return = ret;
 344         #endif
 345         Regs->Error = err;
 346         #if DEBUG
 347         # if DEBUG < 2
 348         if( callNum != SYS_READ && callNum != SYS_WRITE ) {
 349         # endif
 350         LOG("err = %i", err);
 351         if( callNum == SYS_EXECVE )
 352                 LOG("Actual %i", ret);
 353         else
 354                 LEAVE('x', ret);
 355         # if DEBUG < 2
 356         }
 357         # endif
 358         #endif
 359 }
 360
 361 /**
 362  * \fn int Syscall_ValidString(const char *Addr)
 363  * \brief Checks if a memory address contains a valid string
 364  */
 365 int Syscall_ValidString(const char *Addr)
 366 {
 367         // Check if the memory is user memory
 368         if(!MM_IsUser( (tVAddr) Addr))  return 0;
 369
 370         return CheckString( Addr );
 371 }
 372
 373 /**
 374  * \fn int Syscall_Valid(int Size, const void *Addr)
 375  * \brief Checks if a memory address is valid
 376  */
 377 int Syscall_Valid(int Size, const void *Addr)
 378 {
 379         if(!MM_IsUser( (tVAddr)Addr ))  return 0;
 380
 381         return CheckMem( Addr, Size );
 382 }