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
  44         ENTER("iThread iNum", Threads_GetTID(), Regs->Num);
  45         if(Regs->Num < NUM_SYSCALLS)
  46                 LOG("Syscall %s", cSYSCALL_NAMES[Regs->Num]);
  47         LOG("Arg1: 0x%x, Arg2: 0x%x, Arg3: 0x%x, Arg4: 0x%x", Regs->Arg1, Regs->Arg2, Regs->Arg3, Regs->Arg4);
  48
  49         switch(Regs->Num)
  50         {
  51         // -- Exit the current thread
  52         case SYS_EXIT:  Threads_Exit(0, Regs->Arg1);    break;
  53
  54         // -- Put the current thread to sleep
  55         case SYS_SLEEP: Threads_Sleep();        break;
  56
  57         // -- Yield current timeslice
  58         case SYS_YIELD: Threads_Yield();        break;
  59
  60         // -- Set Error Handler
  61         case SYS_SETFAULTHANDLER:
  62                 Threads_SetFaultHandler(Regs->Arg1);
  63                 break;
  64
  65         // -- Clone the current thread
  66         case SYS_CLONE:
  67                 // Call clone system call
  68                 ret = Proc_Clone(&err, Regs->Arg1);
  69                 // Change user stack if a new stack address is passed
  70                 if(ret == 0 && Regs->Arg2)
  71                         Regs->StackPointer = Regs->Arg2;
  72                 break;
  73
  74         // -- Send a signal
  75         case SYS_KILL:
  76                 err = -ENOSYS;
  77                 ret = -1;
  78                 break;
  79
  80         // -- Wait for a thread
  81         case SYS_WAITTID:
  82                 // Sanity Check (Status can be NULL)
  83                 CHECK_NUM_NULLOK( Regs->Arg2, sizeof(int) );
  84                 // TID, *Status
  85                 ret = Threads_WaitTID(Regs->Arg1, (void*)Regs->Arg2);
  86                 break;
  87
  88         // -- Get the physical address of a page
  89         case SYS_GETPHYS:
  90                 ret = MM_GetPhysAddr(Regs->Arg1);
  91                 break;
  92
  93         // -- Map an address
  94         case SYS_MAP:   MM_Map(Regs->Arg1, Regs->Arg2); break;
  95
  96         // -- Allocate an address
  97         case SYS_ALLOCATE:      ret = MM_Allocate(Regs->Arg1);  break;
  98
  99         // -- Unmap an address
 100         case SYS_UNMAP:         MM_Deallocate(Regs->Arg1);      break;
 101
 102         // -- Get Thread/Process IDs
 103         case SYS_GETTID:        ret = Threads_GetTID(); break;
 104         case SYS_GETPID:        ret = Threads_GetPID(); break;
 105
 106         // -- Get User/Group IDs
 107         case SYS_GETUID:        ret = Threads_GetUID(); break;
 108         case SYS_GETGID:        ret = Threads_GetGID(); break;
 109
 110         // -- Set User/Group IDs
 111         case SYS_SETUID:        ret = Threads_SetUID(&err, Regs->Arg1); break;
 112         case SYS_SETGID:        ret = Threads_SetGID(&err, Regs->Arg1); break;
 113
 114         // -- Send Message
 115         case SYS_SENDMSG:
 116                 CHECK_NUM_NONULL(Regs->Arg3, Regs->Arg2);
 117                 // Destination, Size, *Data
 118                 ret = Proc_SendMessage(&err, Regs->Arg1, Regs->Arg2, (void*)Regs->Arg3);
 119                 break;
 120         // -- Check for messages
 121         case SYS_GETMSG:
 122                 CHECK_NUM_NULLOK(Regs->Arg1, sizeof(Uint));
 123                 if( Regs->Arg2 && Regs->Arg2 != -1 && !MM_IsUser(Regs->Arg2) )
 124                 {
 125                         err = -EINVAL;  ret = -1;       break;
 126                 }
 127                 // *Source, *Data
 128                 ret = Proc_GetMessage(&err, (Uint*)Regs->Arg1, (void*)Regs->Arg2);
 129                 break;
 130
 131         // -- Set the thread's name
 132         case SYS_SETNAME:
 133                 CHECK_STR_NONULL(Regs->Arg1);
 134                 Threads_SetName( (char*)Regs->Arg1 );
 135                 break;
 136
 137         // ---
 138         // Binary Control
 139         // ---
 140         case SYS_EXECVE:
 141                 CHECK_STR_NONULL(Regs->Arg1);
 142                 //Log(" Regs = {Arg2: %x, Arg3: %x}", Regs->Arg2, Regs->Arg3);
 143                 {
 144                          int    i;
 145                         char    **tmp = (char**)Regs->Arg2;
 146                         // Check ArgV (traverse array checking all string pointers)
 147                         CHECK_NUM_NONULL( tmp, sizeof(char**) );
 148                         //Log("tmp = %p", tmp);
 149                         for(i=0;tmp[i];i++) {
 150                                 CHECK_NUM_NONULL( &tmp[i], sizeof(char*) );
 151                                 CHECK_STR_NONULL( tmp[i] );
 152                         }
 153                         // Check EnvP also
 154                         // - EnvP can be NULL
 155                         if( Regs->Arg3 )
 156                         {
 157                                 tmp = (char**)Regs->Arg3;
 158                                 //Log("tmp = %p", tmp);
 159                                 for(i=0;tmp[i];i++) {
 160                                         CHECK_NUM_NULLOK( &tmp[i], sizeof(char*) );
 161                                         CHECK_STR_NONULL( tmp[i] );
 162                                 }
 163                         }
 164                 }
 165                 LEAVE('s', "Assuming 0");
 166                 // Path, **Argv, **Envp
 167                 ret = Proc_Execve((char*)Regs->Arg1, (char**)Regs->Arg2, (char**)Regs->Arg3);
 168                 break;
 169         case SYS_LOADBIN:
 170                 if( !Syscall_ValidString(Regs->Arg1)
 171                 ||  !Syscall_Valid(sizeof(Uint), Regs->Arg2) ) {
 172                         err = -EINVAL;
 173                         ret = 0;
 174                         break;
 175                 }
 176                 // Path, *Entrypoint
 177                 ret = Binary_Load((char*)Regs->Arg1, (Uint*)Regs->Arg2);
 178                 break;
 179
 180         // ---
 181         // Virtual Filesystem
 182         // ---
 183         case SYS_OPEN:
 184                 if( !Syscall_ValidString(Regs->Arg1) ) {
 185                         err = -EINVAL;
 186                         ret = -1;
 187                         break;
 188                 }
 189                 ret = VFS_Open((char*)Regs->Arg1, Regs->Arg2 | VFS_OPENFLAG_USER);
 190                 break;
 191
 192         case SYS_CLOSE:
 193                 VFS_Close( Regs->Arg1 );
 194                 break;
 195
 196         case SYS_SEEK:
 197                 #if BITS == 64
 198                 ret = VFS_Seek( Regs->Arg1, Regs->Arg2, Regs->Arg3 );
 199                 #else
 200                 ret = VFS_Seek( Regs->Arg1, Regs->Arg2|(((Uint64)Regs->Arg3)<<32), Regs->Arg4 );
 201                 #endif
 202                 break;
 203
 204         case SYS_TELL:
 205                 ret = VFS_Tell( Regs->Arg1 );
 206                 break;
 207
 208         case SYS_WRITE:
 209                 CHECK_NUM_NONULL( Regs->Arg3, Regs->Arg2 );
 210                 ret = VFS_Write( Regs->Arg1, Regs->Arg2, (void*)Regs->Arg3 );
 211                 break;
 212
 213         case SYS_READ:
 214                 CHECK_NUM_NONULL( Regs->Arg3, Regs->Arg2 );
 215                 ret = VFS_Read( Regs->Arg1, Regs->Arg2, (void*)Regs->Arg3 );
 216                 break;
 217
 218         case SYS_FINFO:
 219                 CHECK_NUM_NONULL( Regs->Arg2, sizeof(tFInfo) + Regs->Arg3*sizeof(tVFS_ACL) );
 220                 // FP, Dest, MaxACLs
 221                 ret = VFS_FInfo( Regs->Arg1, (void*)Regs->Arg2, Regs->Arg3 );
 222                 break;
 223
 224         // Get ACL Value
 225         case SYS_GETACL:
 226                 if( !Syscall_Valid(sizeof(tVFS_ACL), Regs->Arg1) ) {
 227                         err = -EINVAL;
 228                         ret = -1;
 229                         break;
 230                 }
 231                 ret = VFS_GetACL( Regs->Arg1, (void*)Regs->Arg2 );
 232                 break;
 233
 234         // Read Directory
 235         case SYS_READDIR:
 236                 if( !Syscall_Valid(8, Regs->Arg2) ) {
 237                         err = -EINVAL;
 238                         ret = -1;
 239                         break;
 240                 }
 241                 ret = VFS_ReadDir( Regs->Arg1, (void*)Regs->Arg2 );
 242                 break;
 243
 244         // Open a file that is a entry in an open directory
 245         case SYS_OPENCHILD:
 246                 if( !Syscall_ValidString(Regs->Arg2) ) {
 247                         err = -EINVAL;
 248                         ret = -1;
 249                         break;
 250                 }
 251                 ret = VFS_OpenChild( &err, Regs->Arg1, (char*)Regs->Arg2, Regs->Arg3);
 252                 break;
 253
 254         // Change Directory
 255         case SYS_CHDIR:
 256                 if( !Syscall_ValidString(Regs->Arg1) ) {
 257                         err = -EINVAL;
 258                         ret = -1;
 259                         break;
 260                 }
 261                 ret = VFS_ChDir( (void*)Regs->Arg1 );
 262                 break;
 263
 264         // IO Control
 265         case SYS_IOCTL:
 266                 // All sanity checking should be done by the driver
 267                 ret = VFS_IOCtl( Regs->Arg1, Regs->Arg2, (void*)Regs->Arg3 );
 268                 break;
 269
 270         // Mount a filesystem
 271         case SYS_MOUNT:
 272                 // Only root can mount filesystems
 273                 if(Threads_GetUID() != 0) {
 274                         err = -EACCES;
 275                         ret = -1;
 276                         break;
 277                 }
 278                 // Sanity check the paths
 279                 if(!Syscall_ValidString(Regs->Arg1)
 280                 || !Syscall_ValidString(Regs->Arg2)
 281                 || !Syscall_ValidString(Regs->Arg3)
 282                 || !Syscall_ValidString(Regs->Arg4) ) {
 283                         err = -EINVAL;
 284                         ret = -1;
 285                         break;
 286                 }
 287                 ret = VFS_Mount(
 288                         (char*)Regs->Arg1,      // Device
 289                         (char*)Regs->Arg2,      // Mount point
 290                         (char*)Regs->Arg3,      // Filesystem
 291                         (char*)Regs->Arg4       // Options
 292                         );
 293                 break;
 294
 295         // -- Debug
 296         //#if DEBUG_BUILD
 297         case SYS_DEBUG:
 298                 Log((char*)Regs->Arg1,
 299                         Regs->Arg2, Regs->Arg3, Regs->Arg4, Regs->Arg5, Regs->Arg6);
 300                 break;
 301         //#endif
 302
 303         // -- Default (Return Error)
 304         default:
 305                 Warning("SyscallHandler: Unknown System Call %i", Regs->Num);
 306                 if(Regs->Num < NUM_SYSCALLS)
 307                         Warning(" Syscall '%s'", cSYSCALL_NAMES[Regs->Num]);
 308                 err = -ENOSYS;
 309                 ret = -1;
 310                 break;
 311         }
 312
 313         if(err != 0) {
 314                 LOG("ID: %i, Return errno = %i", Regs->Num, err);
 315         }
 316
 317         #if BITS < 64
 318         Regs->Return = ret&0xFFFFFFFF;
 319         Regs->RetHi = ret >> 32;
 320         #else
 321         Regs->Return = ret;
 322         #endif
 323         Regs->Error = err;
 324         #if DEBUG
 325         LOG("err = %i", err);
 326         if(Regs->Num != SYS_EXECVE)
 327                 LEAVE('x', ret);
 328         else
 329                 LOG("Actual %i", ret);
 330         #endif
 331 }
 332
 333 /**
 334  * \fn int Syscall_ValidString(Uint Addr)
 335  * \brief Checks if a memory address contains a valid string
 336  */
 337 int Syscall_ValidString(Uint Addr)
 338 {
 339         // Check if the memory is user memory
 340         if(!MM_IsUser(Addr))    return 0;
 341
 342         return CheckString( (char*)Addr );
 343 }
 344
 345 /**
 346  * \fn int Syscall_Valid(int Size, Uint Addr)
 347  * \brief Checks if a memory address is valid
 348  */
 349 int Syscall_Valid(int Size, Uint Addr)
 350 {
 351         if(!MM_IsUser(Addr))    return 0;
 352
 353         return CheckMem( (void*)Addr, Size );
 354 }