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 int      Proc_Execve(char *File, char **ArgV, char **EnvP);
  26 extern Uint     Binary_Load(const char *file, Uint *entryPoint);
  27
  28 // === PROTOTYPES ===
  29 void    SyscallHandler(tSyscallRegs *Regs);
  30  int    Syscall_ValidString(const char *Addr);
  31  int    Syscall_Valid(int Size, const void *Addr);
  32
  33 // === CODE ===
  34 // TODO: Do sanity checking on arguments, ATM the user can really fuck with the kernel
  35 void SyscallHandler(tSyscallRegs *Regs)
  36 {
  37         Uint64  ret = 0;
  38         Uint    err = -EOK;
  39          int    callNum = Regs->Num;
  40
  41         #if DEBUG < 2
  42         if(callNum != SYS_READ && callNum != SYS_WRITE) {
  43         #endif
  44         ENTER("iThread iNum", Threads_GetTID(), callNum);
  45         if(callNum < NUM_SYSCALLS)
  46                 LOG("Syscall %s", cSYSCALL_NAMES[callNum]);
  47         LOG("Arg1: 0x%x, Arg2: 0x%x, Arg3: 0x%x, Arg4: 0x%x", Regs->Arg1, Regs->Arg2, Regs->Arg3, Regs->Arg4);
  48         #if DEBUG < 2
  49         }
  50         #endif
  51
  52         switch(Regs->Num)
  53         {
  54         // -- Exit the current thread
  55         case SYS_EXIT:  Threads_Exit(0, Regs->Arg1);    break;
  56
  57         // -- Put the current thread to sleep
  58         case SYS_SLEEP: Threads_Sleep();        break;
  59
  60         // -- Yield current timeslice
  61         case SYS_YIELD: Threads_Yield();        break;
  62
  63         // -- Set Error Handler
  64         case SYS_SETFAULTHANDLER:
  65                 Threads_SetFaultHandler(Regs->Arg1);
  66                 break;
  67
  68         // -- Clone the current thread
  69         case SYS_CLONE:
  70                 // Call clone system call
  71                 ret = Proc_Clone(Regs->Arg1);
  72                 break;
  73
  74         // -- Send a signal
  75         case SYS_KILL:
  76                 err = -ENOSYS;
  77                 ret = -1;
  78                 break;
  79
  80         // -- Wait fr an event
  81         case SYS_WAITEVENT:
  82                 // Message mask
  83                 ret = Threads_WaitEvents(Regs->Arg1);
  84                 break;
  85
  86         // -- Wait for a thread
  87         case SYS_WAITTID:
  88                 // Sanity Check (Status can be NULL)
  89                 CHECK_NUM_NULLOK( (int*)Regs->Arg2, sizeof(int) );
  90                 // TID, *Status
  91                 ret = Threads_WaitTID(Regs->Arg1, (int*)Regs->Arg2);
  92                 break;
  93
  94         // -- Get the physical address of a page
  95         case SYS_GETPHYS:
  96                 ret = MM_GetPhysAddr(Regs->Arg1);
  97                 break;
  98
  99         // -- Map an address
 100         case SYS_MAP:   MM_Map(Regs->Arg1, Regs->Arg2); break;
 101
 102         // -- Allocate an address
 103         case SYS_ALLOCATE:      ret = MM_Allocate(Regs->Arg1);  break;
 104
 105         // -- Unmap an address
 106         case SYS_UNMAP:         MM_Deallocate(Regs->Arg1);      break;
 107
 108         // -- Get Thread/Process IDs
 109         case SYS_GETTID:        ret = Threads_GetTID(); break;
 110         case SYS_GETPID:        ret = Threads_GetPID(); break;
 111
 112         // -- Get User/Group IDs
 113         case SYS_GETUID:        ret = Threads_GetUID(); break;
 114         case SYS_GETGID:        ret = Threads_GetGID(); break;
 115
 116         // -- Set User/Group IDs
 117         case SYS_SETUID:        ret = Threads_SetUID(Regs->Arg1);       break;
 118         case SYS_SETGID:        ret = Threads_SetGID(Regs->Arg1);       break;
 119
 120         // -- Send Message
 121         case SYS_SENDMSG:
 122                 CHECK_NUM_NONULL( (void*)Regs->Arg3, Regs->Arg2 );
 123                 // Destination, Size, *Data
 124                 ret = Proc_SendMessage(Regs->Arg1, Regs->Arg2, (void*)Regs->Arg3);
 125                 break;
 126         // -- Check for messages
 127         case SYS_GETMSG:
 128                 CHECK_NUM_NULLOK( (Uint*)Regs->Arg1, sizeof(Uint) );
 129                 // NOTE: Can't do range checking as we don't know the size
 130                 // - Should be done by Proc_GetMessage
 131                 if( Regs->Arg2 && Regs->Arg2 != -1 && !MM_IsUser(Regs->Arg2) ) {
 132                         err = -EINVAL;  ret = -1;       break;
 133                 }
 134                 // *Source, *Data
 135                 ret = Proc_GetMessage((Uint*)Regs->Arg1, (void*)Regs->Arg2);
 136                 break;
 137
 138         // -- Get the current timestamp
 139         case SYS_GETTIME:
 140                 ret = now();
 141                 break;
 142
 143         // -- Set the thread's name
 144         case SYS_SETNAME:
 145                 CHECK_STR_NONULL( (char*) Regs->Arg1);
 146                 Threads_SetName( (char*)Regs->Arg1 );
 147                 break;
 148
 149         // ---
 150         // Binary Control
 151         // ---
 152         // -- Replace the current process with another
 153         case SYS_EXECVE:
 154                 CHECK_STR_NONULL((char*)Regs->Arg1);
 155                 // Check the argument arrays
 156                 {
 157                          int    i;
 158                         char    **tmp = (char**)Regs->Arg2;
 159                         // Check ArgV (traverse array checking all string pointers)
 160                         CHECK_NUM_NONULL( tmp, sizeof(char**) );
 161                         //Log("tmp = %p", tmp);
 162                         for(i=0;tmp[i];i++) {
 163                                 CHECK_NUM_NONULL( &tmp[i], sizeof(char*) );
 164                                 CHECK_STR_NONULL( tmp[i] );
 165                         }
 166                         if(ret == -1) break;
 167                         // Check EnvP also
 168                         // - EnvP can be NULL
 169                         if( Regs->Arg3 )
 170                         {
 171                                 tmp = (char**)Regs->Arg3;
 172                                 CHECK_NUM_NONULL(tmp, sizeof(char**));
 173                                 for(i=0;tmp[i];i++) {
 174                                         CHECK_NUM_NONULL( &tmp[i], sizeof(char*) );
 175                                         CHECK_STR_NONULL( tmp[i] );
 176                                 }
 177                                 if(ret == -1) break;
 178                         }
 179                 }
 180                 LEAVE('s', "Assuming 0");
 181                 // Path, **Argv, **Envp
 182                 ret = Proc_Execve( (char*)Regs->Arg1, (char**)Regs->Arg2, (char**)Regs->Arg3 );
 183                 break;
 184         // -- Load a binary into the current process
 185         case SYS_LOADBIN:
 186                 if( !Syscall_ValidString( (char*) Regs->Arg1)
 187                 ||  !Syscall_Valid(sizeof(Uint), (Uint*)Regs->Arg2) ) {
 188                         err = -EINVAL;
 189                         ret = 0;
 190                         break;
 191                 }
 192                 // Path, *Entrypoint
 193                 ret = Binary_Load((char*)Regs->Arg1, (Uint*)Regs->Arg2);
 194                 break;
 195
 196         // ---
 197         // Virtual Filesystem
 198         // ---
 199         case SYS_OPEN:
 200                 CHECK_STR_NONULL( (char*)Regs->Arg1 );
 201                 LOG("VFS_Open(\"%s\", 0x%x)", (char*)Regs->Arg1, Regs->Arg2 | VFS_OPENFLAG_USER);
 202                 ret = VFS_Open((char*)Regs->Arg1, Regs->Arg2 | VFS_OPENFLAG_USER);
 203                 break;
 204
 205         case SYS_CLOSE:
 206                 LOG("VFS_Close(%i)", Regs->Arg1);
 207                 VFS_Close( Regs->Arg1 );
 208                 break;
 209
 210         case SYS_SEEK:
 211                 #if BITS == 64
 212                 ret = VFS_Seek( Regs->Arg1, Regs->Arg2, Regs->Arg3 );
 213                 #else
 214                 ret = VFS_Seek( Regs->Arg1, Regs->Arg2|(((Uint64)Regs->Arg3)<<32), Regs->Arg4 );
 215                 #endif
 216                 break;
 217
 218         case SYS_TELL:
 219                 ret = VFS_Tell( Regs->Arg1 );
 220                 break;
 221
 222         case SYS_WRITE:
 223                 CHECK_NUM_NONULL( (void*)Regs->Arg2, Regs->Arg3 );
 224                 ret = VFS_Write( Regs->Arg1, Regs->Arg3, (void*)Regs->Arg2 );
 225                 break;
 226
 227         case SYS_READ:
 228                 CHECK_NUM_NONULL( (void*)Regs->Arg2, Regs->Arg3 );
 229                 ret = VFS_Read( Regs->Arg1, Regs->Arg3, (void*)Regs->Arg2 );
 230                 break;
 231
 232         case SYS_FINFO:
 233                 CHECK_NUM_NONULL( (void*)Regs->Arg2, sizeof(tFInfo) + Regs->Arg3*sizeof(tVFS_ACL) );
 234                 // FP, Dest, MaxACLs
 235                 ret = VFS_FInfo( Regs->Arg1, (void*)Regs->Arg2, Regs->Arg3 );
 236                 break;
 237
 238         // Get ACL Value
 239         case SYS_GETACL:
 240                 CHECK_NUM_NONULL( (void*)Regs->Arg2, sizeof(tVFS_ACL) );
 241                 ret = VFS_GetACL( Regs->Arg1, (void*)Regs->Arg2 );
 242                 break;
 243
 244         // Read Directory
 245         case SYS_READDIR:
 246                 // TODO: What if the filename is longer?
 247                 // Maybe force it to be a 256 byte buffer
 248                 CHECK_NUM_NONULL( (void*)Regs->Arg2, 256 );
 249                 ret = VFS_ReadDir( Regs->Arg1, (void*)Regs->Arg2 );
 250                 break;
 251
 252         // Open a file that is a entry in an open directory
 253         case SYS_OPENCHILD:
 254                 CHECK_STR_NONULL( (char*)Regs->Arg2 );
 255                 ret = VFS_OpenChild( Regs->Arg1, (char*)Regs->Arg2, Regs->Arg3);
 256                 break;
 257
 258         // Change Directory
 259         case SYS_CHDIR:
 260                 CHECK_STR_NONULL( (const char*)Regs->Arg1 );
 261                 ret = VFS_ChDir( (const char*)Regs->Arg1 );
 262                 break;
 263
 264         // IO Control
 265         case SYS_IOCTL:
 266                 // All sanity checking should be done by the driver
 267                 if( Regs->Arg3 && !MM_IsUser(Regs->Arg3) ) {
 268                         err = -EINVAL;  ret = -1;       break;
 269                 }
 270                 ret = VFS_IOCtl( Regs->Arg1, Regs->Arg2, (void*)Regs->Arg3 );
 271                 break;
 272
 273         // Mount a filesystem
 274         case SYS_MOUNT:
 275                 // Only root can mount filesystems
 276                 if(Threads_GetUID() != 0) {
 277                         err = -EACCES;
 278                         ret = -1;
 279                         break;
 280                 }
 281                 // Sanity check the paths
 282                 if(!Syscall_ValidString((char*)Regs->Arg1)
 283                 || !Syscall_ValidString((char*)Regs->Arg2)
 284                 || !Syscall_ValidString((char*)Regs->Arg3)
 285                 || !Syscall_ValidString((char*)Regs->Arg4) ) {
 286                         err = -EINVAL;
 287                         ret = -1;
 288                         break;
 289                 }
 290                 ret = VFS_Mount(
 291                         (char*)Regs->Arg1,      // Device
 292                         (char*)Regs->Arg2,      // Mount point
 293                         (char*)Regs->Arg3,      // Filesystem
 294                         (char*)Regs->Arg4       // Options
 295                         );
 296                 break;
 297
 298         // Wait on a set of handles
 299         case SYS_SELECT:
 300                 // Sanity checks
 301                 if( (Regs->Arg2 && !Syscall_Valid(sizeof(fd_set), (void*)Regs->Arg2))
 302                  || (Regs->Arg3 && !Syscall_Valid(sizeof(fd_set), (void*)Regs->Arg3))
 303                  || (Regs->Arg4 && !Syscall_Valid(sizeof(fd_set), (void*)Regs->Arg4))
 304                  || (Regs->Arg5 && !Syscall_Valid(sizeof(tTime), (void*)Regs->Arg5)) )
 305                 {
 306                         err = -EINVAL;
 307                         ret = -1;
 308                         break;
 309                 }
 310                 // Perform the call
 311                 ret = VFS_Select(
 312                         Regs->Arg1,     // Max handle
 313                         (fd_set *)Regs->Arg2,   // Read
 314                         (fd_set *)Regs->Arg3,   // Write
 315                         (fd_set *)Regs->Arg4,   // Errors
 316                         (tTime *)Regs->Arg5,    // Timeout
 317                         (Uint32)Regs->Arg6,     // Extra wakeup events
 318                         0       // User handles
 319                         );
 320                 break;
 321
 322         // -- Debug
 323         //#if DEBUG_BUILD
 324         case SYS_DEBUG:
 325                 CHECK_STR_NONULL( (char*)Regs->Arg1 );
 326                 LogF("Log: %08lli [%i] ", now(), Threads_GetTID());
 327                 LogF((const char*)Regs->Arg1,
 328                         Regs->Arg2, Regs->Arg3, Regs->Arg4, Regs->Arg5, Regs->Arg6);
 329                 LogF("\r\n");
 330                 break;
 331         //#endif
 332
 333         // -- Default (Return Error)
 334         default:
 335                 Log_Warning("Syscalls", "Unknown System Call %i", Regs->Num);
 336                 if(Regs->Num < NUM_SYSCALLS)
 337                         Log_Warning("Syscall", " named '%s'", cSYSCALL_NAMES[Regs->Num]);
 338                 err = -ENOSYS;
 339                 ret = -1;
 340                 break;
 341         }
 342
 343         if(err == 0)    err = errno;
 344
 345         if(err != 0) {
 346                 LOG("ID: %i, Return errno = %i", Regs->Num, err);
 347         }
 348
 349         #if BITS < 64
 350         Regs->Return = ret&0xFFFFFFFF;
 351         Regs->RetHi = ret >> 32;
 352         #else
 353         Regs->Return = ret;
 354         #endif
 355         Regs->Error = err;
 356         #if DEBUG
 357         # if DEBUG < 2
 358         if( callNum != SYS_READ && callNum != SYS_WRITE ) {
 359         # endif
 360         LOG("err = %i", err);
 361         if( callNum == SYS_EXECVE )
 362                 LOG("Actual %i", ret);
 363         else
 364                 LEAVE('x', ret);
 365         # if DEBUG < 2
 366         }
 367         # endif
 368         #endif
 369 }
 370
 371 /**
 372  * \fn int Syscall_ValidString(const char *Addr)
 373  * \brief Checks if a memory address contains a valid string
 374  */
 375 int Syscall_ValidString(const char *Addr)
 376 {
 377         // Check if the memory is user memory
 378         if(!MM_IsUser( (tVAddr) Addr))  return 0;
 379
 380         return CheckString( Addr );
 381 }
 382
 383 /**
 384  * \fn int Syscall_Valid(int Size, const void *Addr)
 385  * \brief Checks if a memory address is valid
 386  */
 387 int Syscall_Valid(int Size, const void *Addr)
 388 {
 389         if(!MM_IsUser( (tVAddr)Addr ))  return 0;
 390
 391         return CheckMem( Addr, Size );
 392 }