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