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 #include <events.h>
  14
  15 #define CHECK_NUM_NULLOK(v,size)        \
  16         if((v)&&!Syscall_Valid((size),(v))){ret=-1;err=-EINVAL;break;}
  17 #define CHECK_STR_NULLOK(v)     \
  18         if((v)&&!Syscall_ValidString((v))){ret=-1;err=-EINVAL;break;}
  19 #define CHECK_NUM_NONULL(v,size)        \
  20         if(!(v)||!Syscall_Valid((size),(v))){ret=-1;err=-EINVAL;break;}
  21 #define CHECK_STR_NONULL(v)     \
  22         if(!(v)||!Syscall_ValidString((v))){ret=-1;err=-EINVAL;break;}
  23
  24 // === IMPORTS ===
  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 fr an event
  80         case SYS_WAITEVENT:
  81                 // Message mask
  82                 ret = Threads_WaitEvents(Regs->Arg1);
  83                 break;
  84
  85         // -- Wait for a thread
  86         case SYS_WAITTID:
  87                 // Sanity Check (Status can be NULL)
  88                 CHECK_NUM_NULLOK( (int*)Regs->Arg2, sizeof(int) );
  89                 // TID, *Status
  90                 ret = Threads_WaitTID(Regs->Arg1, (int*)Regs->Arg2);
  91                 break;
  92
  93         // -- Get the physical address of a page
  94         case SYS_GETPHYS:
  95                 ret = MM_GetPhysAddr(Regs->Arg1);
  96                 break;
  97
  98         // -- Map an address
  99         case SYS_MAP:   MM_Map(Regs->Arg1, Regs->Arg2); break;
 100
 101         // -- Allocate an address
 102         case SYS_ALLOCATE:      ret = MM_Allocate(Regs->Arg1);  break;
 103
 104         // -- Unmap an address
 105         case SYS_UNMAP:         MM_Deallocate(Regs->Arg1);      break;
 106
 107         // -- Get Thread/Process IDs
 108         case SYS_GETTID:        ret = Threads_GetTID(); break;
 109         case SYS_GETPID:        ret = Threads_GetPID(); break;
 110
 111         // -- Get User/Group IDs
 112         case SYS_GETUID:        ret = Threads_GetUID(); break;
 113         case SYS_GETGID:        ret = Threads_GetGID(); break;
 114
 115         // -- Set User/Group IDs
 116         case SYS_SETUID:        ret = Threads_SetUID(Regs->Arg1);       break;
 117         case SYS_SETGID:        ret = Threads_SetGID(Regs->Arg1);       break;
 118
 119         // -- Send Message
 120         case SYS_SENDMSG:
 121                 CHECK_NUM_NONULL( (void*)Regs->Arg3, Regs->Arg2 );
 122                 // Destination, Size, *Data
 123                 ret = Proc_SendMessage(Regs->Arg1, Regs->Arg2, (void*)Regs->Arg3);
 124                 break;
 125         // -- Check for messages
 126         case SYS_GETMSG:
 127                 CHECK_NUM_NULLOK( (Uint*)Regs->Arg1, sizeof(Uint) );
 128                 // NOTE: Can't do range checking as we don't know the size
 129                 // - Should be done by Proc_GetMessage
 130                 if( Regs->Arg2 && Regs->Arg2 != -1 && !MM_IsUser(Regs->Arg2) ) {
 131                         err = -EINVAL;  ret = -1;       break;
 132                 }
 133                 // *Source, *Data
 134                 ret = Proc_GetMessage((Uint*)Regs->Arg1, (void*)Regs->Arg2);
 135                 break;
 136
 137         // -- Get the current timestamp
 138         case SYS_GETTIME:
 139                 ret = now();
 140                 break;
 141
 142         // -- Set the thread's name
 143         case SYS_SETNAME:
 144                 CHECK_STR_NONULL( (char*) Regs->Arg1);
 145                 Threads_SetName( (char*)Regs->Arg1 );
 146                 break;
 147
 148         // ---
 149         // Binary Control
 150         // ---
 151         // -- Replace the current process with another
 152         case SYS_EXECVE:
 153                 CHECK_STR_NONULL((char*)Regs->Arg1);
 154                 // Check the argument arrays
 155                 {
 156                          int    i;
 157                         char    **tmp = (char**)Regs->Arg2;
 158                         // Check ArgV (traverse array checking all string pointers)
 159                         CHECK_NUM_NONULL( tmp, sizeof(char**) );
 160                         //Log("tmp = %p", tmp);
 161                         for(i=0;tmp[i];i++) {
 162                                 CHECK_NUM_NONULL( &tmp[i], sizeof(char*) );
 163                                 CHECK_STR_NONULL( tmp[i] );
 164                         }
 165                         if(ret == -1) break;
 166                         // Check EnvP also
 167                         // - EnvP can be NULL
 168                         if( Regs->Arg3 )
 169                         {
 170                                 tmp = (char**)Regs->Arg3;
 171                                 CHECK_NUM_NONULL(tmp, sizeof(char**));
 172                                 for(i=0;tmp[i];i++) {
 173                                         CHECK_NUM_NONULL( &tmp[i], sizeof(char*) );
 174                                         CHECK_STR_NONULL( tmp[i] );
 175                                 }
 176                                 if(ret == -1) break;
 177                         }
 178                 }
 179                 LEAVE('s', "Assuming 0");
 180                 // Path, **Argv, **Envp, DataSize (=0 to tell it to create a copy)
 181                 ret = Proc_Execve( (const char*)Regs->Arg1, (const char**)Regs->Arg2, (const char**)Regs->Arg3, 0 );
 182                 break;
 183         // -- Load a binary into the current process
 184         case SYS_LOADBIN:
 185                 if( !Syscall_ValidString( (char*) Regs->Arg1)
 186                 ||  !Syscall_Valid(sizeof(Uint), (Uint*)Regs->Arg2) ) {
 187                         err = -EINVAL;
 188                         ret = 0;
 189                         break;
 190                 }
 191                 // Path, *Entrypoint
 192                 ret = Binary_Load((char*)Regs->Arg1, (Uint*)Regs->Arg2);
 193                 break;
 194
 195         // ---
 196         // Virtual Filesystem
 197         // ---
 198         case SYS_OPEN:
 199                 CHECK_STR_NONULL( (char*)Regs->Arg1 );
 200                 LOG("VFS_Open(\"%s\", 0x%x)", (char*)Regs->Arg1, Regs->Arg2 | VFS_OPENFLAG_USER);
 201                 ret = VFS_Open((char*)Regs->Arg1, Regs->Arg2 | VFS_OPENFLAG_USER);
 202                 break;
 203
 204         case SYS_CLOSE:
 205                 LOG("VFS_Close(%i)", Regs->Arg1);
 206                 VFS_Close( Regs->Arg1 );
 207                 break;
 208
 209         case SYS_SEEK:
 210                 #if BITS == 64
 211                 ret = VFS_Seek( Regs->Arg1, Regs->Arg2, Regs->Arg3 );
 212                 #else
 213                 ret = VFS_Seek( Regs->Arg1, Regs->Arg2|(((Uint64)Regs->Arg3)<<32), Regs->Arg4 );
 214                 #endif
 215                 break;
 216
 217         case SYS_TELL:
 218                 ret = VFS_Tell( Regs->Arg1 );
 219                 break;
 220
 221         case SYS_WRITE:
 222                 CHECK_NUM_NONULL( (void*)Regs->Arg2, Regs->Arg3 );
 223                 ret = VFS_Write( Regs->Arg1, Regs->Arg3, (void*)Regs->Arg2 );
 224                 break;
 225
 226         case SYS_READ:
 227                 CHECK_NUM_NONULL( (void*)Regs->Arg2, Regs->Arg3 );
 228                 ret = VFS_Read( Regs->Arg1, Regs->Arg3, (void*)Regs->Arg2 );
 229                 break;
 230
 231         case SYS_FINFO:
 232                 CHECK_NUM_NONULL( (void*)Regs->Arg2, sizeof(tFInfo) + Regs->Arg3*sizeof(tVFS_ACL) );
 233                 // FP, Dest, MaxACLs
 234                 ret = VFS_FInfo( Regs->Arg1, (void*)Regs->Arg2, Regs->Arg3 );
 235                 break;
 236
 237         // Get ACL Value
 238         case SYS_GETACL:
 239                 CHECK_NUM_NONULL( (void*)Regs->Arg2, sizeof(tVFS_ACL) );
 240                 ret = VFS_GetACL( Regs->Arg1, (void*)Regs->Arg2 );
 241                 break;
 242
 243         // Read Directory
 244         case SYS_READDIR:
 245                 // TODO: What if the filename is longer?
 246                 // Maybe force it to be a 256 byte buffer
 247                 CHECK_NUM_NONULL( (void*)Regs->Arg2, 256 );
 248                 ret = VFS_ReadDir( Regs->Arg1, (void*)Regs->Arg2 );
 249                 break;
 250
 251         // Open a file that is a entry in an open directory
 252         case SYS_OPENCHILD:
 253                 CHECK_STR_NONULL( (char*)Regs->Arg2 );
 254                 ret = VFS_OpenChild( Regs->Arg1, (char*)Regs->Arg2, Regs->Arg3);
 255                 break;
 256
 257         // Change Directory
 258         case SYS_CHDIR:
 259                 CHECK_STR_NONULL( (const char*)Regs->Arg1 );
 260                 ret = VFS_ChDir( (const char*)Regs->Arg1 );
 261                 break;
 262
 263         // IO Control
 264         case SYS_IOCTL:
 265                 // All sanity checking should be done by the driver
 266                 if( Regs->Arg3 && !MM_IsUser(Regs->Arg3) ) {
 267                         err = -EINVAL;  ret = -1;       break;
 268                 }
 269                 ret = VFS_IOCtl( Regs->Arg1, Regs->Arg2, (void*)Regs->Arg3 );
 270                 break;
 271
 272         // Mount a filesystem
 273         case SYS_MOUNT:
 274                 // Only root can mount filesystems
 275                 if(Threads_GetUID() != 0) {
 276                         err = -EACCES;
 277                         ret = -1;
 278                         break;
 279                 }
 280                 // Sanity check the paths
 281                 if(!Syscall_ValidString((char*)Regs->Arg1)
 282                 || !Syscall_ValidString((char*)Regs->Arg2)
 283                 || !Syscall_ValidString((char*)Regs->Arg3)
 284                 || !Syscall_ValidString((char*)Regs->Arg4) ) {
 285                         err = -EINVAL;
 286                         ret = -1;
 287                         break;
 288                 }
 289                 ret = VFS_Mount(
 290                         (char*)Regs->Arg1,      // Device
 291                         (char*)Regs->Arg2,      // Mount point
 292                         (char*)Regs->Arg3,      // Filesystem
 293                         (char*)Regs->Arg4       // Options
 294                         );
 295                 break;
 296
 297         // Wait on a set of handles
 298         case SYS_SELECT:
 299                 // Sanity checks
 300                 if( (Regs->Arg2 && !Syscall_Valid(sizeof(fd_set), (void*)Regs->Arg2))
 301                  || (Regs->Arg3 && !Syscall_Valid(sizeof(fd_set), (void*)Regs->Arg3))
 302                  || (Regs->Arg4 && !Syscall_Valid(sizeof(fd_set), (void*)Regs->Arg4))
 303                  || (Regs->Arg5 && !Syscall_Valid(sizeof(tTime), (void*)Regs->Arg5)) )
 304                 {
 305                         err = -EINVAL;
 306                         ret = -1;
 307                         break;
 308                 }
 309                 // Perform the call
 310                 ret = VFS_Select(
 311                         Regs->Arg1,     // Max handle
 312                         (fd_set *)Regs->Arg2,   // Read
 313                         (fd_set *)Regs->Arg3,   // Write
 314                         (fd_set *)Regs->Arg4,   // Errors
 315                         (tTime *)Regs->Arg5,    // Timeout
 316                         (Uint32)Regs->Arg6,     // Extra wakeup events
 317                         0       // User handles
 318                         );
 319                 break;
 320
 321         // -- Debug
 322         //#if DEBUG_BUILD
 323         case SYS_DEBUG:
 324                 CHECK_STR_NONULL( (char*)Regs->Arg1 );
 325                 LogF("Log: %08lli [%i] ", now(), Threads_GetTID());
 326                 LogF((const char*)Regs->Arg1,
 327                         Regs->Arg2, Regs->Arg3, Regs->Arg4, Regs->Arg5, Regs->Arg6);
 328                 LogF("\r\n");
 329                 break;
 330         //#endif
 331
 332         // -- Default (Return Error)
 333         default:
 334                 Log_Warning("Syscalls", "Unknown System Call %i", Regs->Num);
 335                 if(Regs->Num < NUM_SYSCALLS)
 336                         Log_Warning("Syscall", " named '%s'", cSYSCALL_NAMES[Regs->Num]);
 337                 err = -ENOSYS;
 338                 ret = -1;
 339                 break;
 340         }
 341
 342         if(err == 0)    err = errno;
 343
 344         if(err != 0) {
 345                 LOG("ID: %i, Return errno = %i", Regs->Num, err);
 346         }
 347
 348         #if BITS < 64
 349         Regs->Return = ret&0xFFFFFFFF;
 350         Regs->RetHi = ret >> 32;
 351         #else
 352         Regs->Return = ret;
 353         #endif
 354         Regs->Error = err;
 355         #if DEBUG
 356         # if DEBUG < 2
 357         if( callNum != SYS_READ && callNum != SYS_WRITE ) {
 358         # endif
 359         LOG("err = %i", err);
 360         if( callNum == SYS_EXECVE )
 361                 LOG("Actual %i", ret);
 362         else
 363                 LEAVE('x', ret);
 364         # if DEBUG < 2
 365         }
 366         # endif
 367         #endif
 368 }
 369
 370 /**
 371  * \fn int Syscall_ValidString(const char *Addr)
 372  * \brief Checks if a memory address contains a valid string
 373  */
 374 int Syscall_ValidString(const char *Addr)
 375 {
 376         // Check if the memory is user memory
 377         if(!MM_IsUser( (tVAddr) Addr))  return 0;
 378
 379         return CheckString( Addr );
 380 }
 381
 382 /**
 383  * \fn int Syscall_Valid(int Size, const void *Addr)
 384  * \brief Checks if a memory address is valid
 385  */
 386 int Syscall_Valid(int Size, const void *Addr)
 387 {
 388         if(!MM_IsUser( (tVAddr)Addr ))  return 0;
 389
 390         return CheckMem( Addr, Size );
 391 }