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