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                         err = -EINVAL;  ret = -1;       break;
 125                 }
 126                 // *Source, *Data
 127                 ret = Proc_GetMessage(&err, (Uint*)Regs->Arg1, (void*)Regs->Arg2);
 128                 break;
 129
 130         // -- Get the current timestamp
 131         case SYS_GETTIME:
 132                 ret = now();
 133                 break;
 134
 135         // -- Set the thread's name
 136         case SYS_SETNAME:
 137                 CHECK_STR_NONULL(Regs->Arg1);
 138                 Threads_SetName( (char*)Regs->Arg1 );
 139                 break;
 140
 141         // ---
 142         // Binary Control
 143         // ---
 144         // -- Replace the current process with another
 145         case SYS_EXECVE:
 146                 CHECK_STR_NONULL(Regs->Arg1);
 147                 // Check the argument arrays
 148                 {
 149                          int    i;
 150                         char    **tmp = (char**)Regs->Arg2;
 151                         // Check ArgV (traverse array checking all string pointers)
 152                         CHECK_NUM_NONULL( tmp, sizeof(char**) );
 153                         //Log("tmp = %p", tmp);
 154                         for(i=0;tmp[i];i++) {
 155                                 CHECK_NUM_NONULL( &tmp[i], sizeof(char*) );
 156                                 CHECK_STR_NONULL( tmp[i] );
 157                         }
 158                         // Check EnvP also
 159                         // - EnvP can be NULL
 160                         if( Regs->Arg3 )
 161                         {
 162                                 tmp = (char**)Regs->Arg3;
 163                                 //Log("tmp = %p", tmp);
 164                                 for(i=0;tmp[i];i++) {
 165                                         CHECK_NUM_NULLOK( &tmp[i], sizeof(char*) );
 166                                         CHECK_STR_NONULL( tmp[i] );
 167                                 }
 168                         }
 169                 }
 170                 LEAVE('s', "Assuming 0");
 171                 // Path, **Argv, **Envp
 172                 ret = Proc_Execve((char*)Regs->Arg1, (char**)Regs->Arg2, (char**)Regs->Arg3);
 173                 break;
 174         // -- Load a binary into the current process
 175         case SYS_LOADBIN:
 176                 if( !Syscall_ValidString(Regs->Arg1)
 177                 ||  !Syscall_Valid(sizeof(Uint), Regs->Arg2) ) {
 178                         err = -EINVAL;
 179                         ret = 0;
 180                         break;
 181                 }
 182                 // Path, *Entrypoint
 183                 ret = Binary_Load((char*)Regs->Arg1, (Uint*)Regs->Arg2);
 184                 break;
 185
 186         // ---
 187         // Virtual Filesystem
 188         // ---
 189         case SYS_OPEN:
 190                 if( !Syscall_ValidString(Regs->Arg1) ) {
 191                         err = -EINVAL;
 192                         ret = -1;
 193                         break;
 194                 }
 195                 ret = VFS_Open((char*)Regs->Arg1, Regs->Arg2 | VFS_OPENFLAG_USER);
 196                 break;
 197
 198         case SYS_CLOSE:
 199                 VFS_Close( Regs->Arg1 );
 200                 break;
 201
 202         case SYS_SEEK:
 203                 #if BITS == 64
 204                 ret = VFS_Seek( Regs->Arg1, Regs->Arg2, Regs->Arg3 );
 205                 #else
 206                 ret = VFS_Seek( Regs->Arg1, Regs->Arg2|(((Uint64)Regs->Arg3)<<32), Regs->Arg4 );
 207                 #endif
 208                 break;
 209
 210         case SYS_TELL:
 211                 ret = VFS_Tell( Regs->Arg1 );
 212                 break;
 213
 214         case SYS_WRITE:
 215                 CHECK_NUM_NONULL( Regs->Arg3, Regs->Arg2 );
 216                 ret = VFS_Write( Regs->Arg1, Regs->Arg2, (void*)Regs->Arg3 );
 217                 break;
 218
 219         case SYS_READ:
 220                 CHECK_NUM_NONULL( Regs->Arg3, Regs->Arg2 );
 221                 ret = VFS_Read( Regs->Arg1, Regs->Arg2, (void*)Regs->Arg3 );
 222                 break;
 223
 224         case SYS_FINFO:
 225                 CHECK_NUM_NONULL( Regs->Arg2, sizeof(tFInfo) + Regs->Arg3*sizeof(tVFS_ACL) );
 226                 // FP, Dest, MaxACLs
 227                 ret = VFS_FInfo( Regs->Arg1, (void*)Regs->Arg2, Regs->Arg3 );
 228                 break;
 229
 230         // Get ACL Value
 231         case SYS_GETACL:
 232                 if( !Syscall_Valid(sizeof(tVFS_ACL), Regs->Arg1) ) {
 233                         err = -EINVAL;
 234                         ret = -1;
 235                         break;
 236                 }
 237                 ret = VFS_GetACL( Regs->Arg1, (void*)Regs->Arg2 );
 238                 break;
 239
 240         // Read Directory
 241         case SYS_READDIR:
 242                 if( !Syscall_Valid(8, Regs->Arg2) ) {
 243                         err = -EINVAL;
 244                         ret = -1;
 245                         break;
 246                 }
 247                 ret = VFS_ReadDir( Regs->Arg1, (void*)Regs->Arg2 );
 248                 break;
 249
 250         // Open a file that is a entry in an open directory
 251         case SYS_OPENCHILD:
 252                 if( !Syscall_ValidString(Regs->Arg2) ) {
 253                         err = -EINVAL;
 254                         ret = -1;
 255                         break;
 256                 }
 257                 ret = VFS_OpenChild( &err, Regs->Arg1, (char*)Regs->Arg2, Regs->Arg3);
 258                 break;
 259
 260         // Change Directory
 261         case SYS_CHDIR:
 262                 if( !Syscall_ValidString(Regs->Arg1) ) {
 263                         err = -EINVAL;
 264                         ret = -1;
 265                         break;
 266                 }
 267                 ret = VFS_ChDir( (void*)Regs->Arg1 );
 268                 break;
 269
 270         // IO Control
 271         case SYS_IOCTL:
 272                 // All sanity checking should be done by the driver
 273                 ret = VFS_IOCtl( Regs->Arg1, Regs->Arg2, (void*)Regs->Arg3 );
 274                 break;
 275
 276         // Mount a filesystem
 277         case SYS_MOUNT:
 278                 // Only root can mount filesystems
 279                 if(Threads_GetUID() != 0) {
 280                         err = -EACCES;
 281                         ret = -1;
 282                         break;
 283                 }
 284                 // Sanity check the paths
 285                 if(!Syscall_ValidString(Regs->Arg1)
 286                 || !Syscall_ValidString(Regs->Arg2)
 287                 || !Syscall_ValidString(Regs->Arg3)
 288                 || !Syscall_ValidString(Regs->Arg4) ) {
 289                         err = -EINVAL;
 290                         ret = -1;
 291                         break;
 292                 }
 293                 ret = VFS_Mount(
 294                         (char*)Regs->Arg1,      // Device
 295                         (char*)Regs->Arg2,      // Mount point
 296                         (char*)Regs->Arg3,      // Filesystem
 297                         (char*)Regs->Arg4       // Options
 298                         );
 299                 break;
 300
 301         // -- Debug
 302         //#if DEBUG_BUILD
 303         case SYS_DEBUG:
 304                 Log((char*)Regs->Arg1,
 305                         Regs->Arg2, Regs->Arg3, Regs->Arg4, Regs->Arg5, Regs->Arg6);
 306                 break;
 307         //#endif
 308
 309         // -- Default (Return Error)
 310         default:
 311                 Warning("SyscallHandler: Unknown System Call %i", Regs->Num);
 312                 if(Regs->Num < NUM_SYSCALLS)
 313                         Warning(" Syscall '%s'", cSYSCALL_NAMES[Regs->Num]);
 314                 err = -ENOSYS;
 315                 ret = -1;
 316                 break;
 317         }
 318
 319         if(err != 0) {
 320                 LOG("ID: %i, Return errno = %i", Regs->Num, err);
 321         }
 322
 323         #if BITS < 64
 324         Regs->Return = ret&0xFFFFFFFF;
 325         Regs->RetHi = ret >> 32;
 326         #else
 327         Regs->Return = ret;
 328         #endif
 329         Regs->Error = err;
 330         #if DEBUG
 331         LOG("err = %i", err);
 332         if(Regs->Num != SYS_EXECVE)
 333                 LEAVE('x', ret);
 334         else
 335                 LOG("Actual %i", ret);
 336         #endif
 337 }
 338
 339 /**
 340  * \fn int Syscall_ValidString(Uint Addr)
 341  * \brief Checks if a memory address contains a valid string
 342  */
 343 int Syscall_ValidString(Uint Addr)
 344 {
 345         // Check if the memory is user memory
 346         if(!MM_IsUser(Addr))    return 0;
 347
 348         return CheckString( (char*)Addr );
 349 }
 350
 351 /**
 352  * \fn int Syscall_Valid(int Size, Uint Addr)
 353  * \brief Checks if a memory address is valid
 354  */
 355 int Syscall_Valid(int Size, Uint Addr)
 356 {
 357         if(!MM_IsUser(Addr))    return 0;
 358
 359         return CheckMem( (void*)Addr, Size );
 360 }