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