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_GetPID();
  30 extern int      Threads_GetTID();
  31 extern tUID     Threads_GetUID();
  32 extern int      Threads_SetUID(Uint *errno, tUID ID);
  33 extern tGID     Threads_GetGID();
  34 extern int      Threads_SetGID(Uint *errno, tGID ID);
  35
  36 // === PROTOTYPES ===
  37  int    Syscall_ValidString(Uint Addr);
  38  int    Syscall_Valid(int Size, Uint Addr);
  39
  40 // === CODE ===
  41 // TODO: Do sanity checking on arguments, ATM the user can really fuck with the kernel
  42 void SyscallHandler(tSyscallRegs *Regs)
  43 {
  44         Uint64  ret = 0;
  45         Uint    err = -EOK;
  46
  47         ENTER("iThread iNum", Threads_GetTID(), Regs->Num);
  48         if(Regs->Num < NUM_SYSCALLS)
  49                 LOG("Syscall %s", cSYSCALL_NAMES[Regs->Num]);
  50         LOG("Arg1: 0x%x, Arg2: 0x%x, Arg3: 0x%x, Arg4: 0x%x", Regs->Arg1, Regs->Arg2, Regs->Arg3, Regs->Arg4);
  51
  52         switch(Regs->Num)
  53         {
  54         // -- Exit the current thread
  55         case SYS_EXIT:  Threads_Exit(0, Regs->Arg1);    break;
  56
  57         // -- Put the current thread to sleep
  58         case SYS_SLEEP: Threads_Sleep();        break;
  59
  60         // -- Yield current timeslice
  61         case SYS_YIELD: Threads_Yield();        break;
  62
  63         // -- Clone the current thread
  64         case SYS_CLONE:
  65                 // Call clone system call
  66                 ret = Proc_Clone(&err, Regs->Arg1);
  67                 // Change user stack if a new stack address is passed
  68                 if(ret == 0 && Regs->Arg2)
  69                         Regs->StackPointer = Regs->Arg2;
  70                 break;
  71
  72         // -- Send a signal
  73         case SYS_KILL:
  74                 err = -ENOSYS;
  75                 ret = -1;
  76                 break;
  77
  78         // -- Wait for a thread
  79         case SYS_WAITTID:
  80                 // Sanity Check (Status can be NULL)
  81                 CHECK_NUM_NULLOK( Regs->Arg2, sizeof(int) );
  82                 // TID, *Status
  83                 ret = Threads_WaitTID(Regs->Arg1, (void*)Regs->Arg2);
  84                 break;
  85
  86         // -- Get the physical address of a page
  87         case SYS_GETPHYS:
  88                 ret = MM_GetPhysAddr(Regs->Arg1);
  89                 break;
  90
  91         // -- Map an address
  92         case SYS_MAP:   MM_Map(Regs->Arg1, Regs->Arg2); break;
  93
  94         // -- Allocate an address
  95         case SYS_ALLOCATE:      ret = MM_Allocate(Regs->Arg1);  break;
  96
  97         // -- Unmap an address
  98         case SYS_UNMAP:         MM_Deallocate(Regs->Arg1);      break;
  99
 100         // -- Get Thread/Process IDs
 101         case SYS_GETTID:        ret = Threads_GetTID(); break;
 102         case SYS_GETPID:        ret = Threads_GetPID(); break;
 103
 104         // -- Get User/Group IDs
 105         case SYS_GETUID:        ret = Threads_GetUID(); break;
 106         case SYS_GETGID:        ret = Threads_GetGID(); break;
 107
 108         // -- Set User/Group IDs
 109         case SYS_SETUID:        ret = Threads_SetUID(&err, Regs->Arg1); break;
 110         case SYS_SETGID:        ret = Threads_SetGID(&err, Regs->Arg1); break;
 111
 112         // -- Send Message
 113         case SYS_SENDMSG:
 114                 CHECK_NUM_NONULL(Regs->Arg3, Regs->Arg2);
 115                 // Destination, Size, *Data
 116                 ret = Proc_SendMessage(&err, Regs->Arg1, Regs->Arg2, (void*)Regs->Arg3);
 117                 break;
 118         // -- Check for messages
 119         case SYS_GETMSG:
 120                 CHECK_NUM_NULLOK(Regs->Arg1, sizeof(Uint));
 121                 if( Regs->Arg2 && Regs->Arg2 != -1 && !MM_IsUser(Regs->Arg2) )
 122                 {
 123                         err = -EINVAL;  ret = -1;       break;
 124                 }
 125                 // *Source, *Data
 126                 ret = Proc_GetMessage(&err, (Uint*)Regs->Arg1, (void*)Regs->Arg2);
 127                 break;
 128
 129         // -- Set the thread's name
 130         case SYS_SETNAME:
 131                 CHECK_STR_NONULL(Regs->Arg1);
 132                 Threads_SetName( (char*)Regs->Arg1 );
 133                 break;
 134
 135         // ---
 136         // Binary Control
 137         // ---
 138         case SYS_EXECVE:
 139                 CHECK_STR_NONULL(Regs->Arg1);
 140                 //Log(" Regs = {Arg2: %x, Arg3: %x}", Regs->Arg2, Regs->Arg3);
 141                 {
 142                          int    i;
 143                         char    **tmp = (char**)Regs->Arg2;
 144                         // Check ArgV (traverse array checking all string pointers)
 145                         CHECK_NUM_NONULL( tmp, sizeof(char**) );
 146                         //Log("tmp = %p", tmp);
 147                         for(i=0;tmp[i];i++) {
 148                                 CHECK_NUM_NONULL( &tmp[i], sizeof(char*) );
 149                                 CHECK_STR_NONULL( tmp[i] );
 150                         }
 151                         // Check EnvP also
 152                         // - EnvP can be NULL
 153                         if( Regs->Arg3 )
 154                         {
 155                                 tmp = (char**)Regs->Arg3;
 156                                 //Log("tmp = %p", tmp);
 157                                 for(i=0;tmp[i];i++) {
 158                                         CHECK_NUM_NULLOK( &tmp[i], sizeof(char*) );
 159                                         CHECK_STR_NONULL( tmp[i] );
 160                                 }
 161                         }
 162                 }
 163                 LEAVE('s', "Assuming 0");
 164                 // Path, **Argv, **Envp
 165                 ret = Proc_Execve((char*)Regs->Arg1, (char**)Regs->Arg2, (char**)Regs->Arg3);
 166                 break;
 167         case SYS_LOADBIN:
 168                 if( !Syscall_ValidString(Regs->Arg1)
 169                 ||  !Syscall_Valid(sizeof(Uint), Regs->Arg2) ) {
 170                         err = -EINVAL;
 171                         ret = 0;
 172                         break;
 173                 }
 174                 // Path, *Entrypoint
 175                 ret = Binary_Load((char*)Regs->Arg1, (Uint*)Regs->Arg2);
 176                 break;
 177
 178         // ---
 179         // Virtual Filesystem
 180         // ---
 181         case SYS_OPEN:
 182                 if( !Syscall_ValidString(Regs->Arg1) ) {
 183                         err = -EINVAL;
 184                         ret = -1;
 185                         break;
 186                 }
 187                 ret = VFS_Open((char*)Regs->Arg1, Regs->Arg2 | VFS_OPENFLAG_USER);
 188                 break;
 189
 190         case SYS_CLOSE:
 191                 VFS_Close( Regs->Arg1 );
 192                 break;
 193
 194         case SYS_SEEK:
 195                 ret = VFS_Seek( Regs->Arg1, Regs->Arg2, Regs->Arg3 );
 196                 break;
 197
 198         case SYS_TELL:
 199                 ret = VFS_Tell( Regs->Arg1 );
 200                 break;
 201
 202         case SYS_WRITE:
 203                 CHECK_NUM_NONULL( Regs->Arg3, Regs->Arg2 );
 204                 ret = VFS_Write( Regs->Arg1, Regs->Arg2, (void*)Regs->Arg3 );
 205                 break;
 206
 207         case SYS_READ:
 208                 CHECK_NUM_NONULL( Regs->Arg3, Regs->Arg2 );
 209                 ret = VFS_Read( Regs->Arg1, Regs->Arg2, (void*)Regs->Arg3 );
 210                 break;
 211
 212         case SYS_FINFO:
 213                 CHECK_NUM_NONULL( Regs->Arg2, sizeof(tFInfo) + Regs->Arg3*sizeof(tVFS_ACL) );
 214                 // FP, Dest, MaxACLs
 215                 ret = VFS_FInfo( Regs->Arg1, (void*)Regs->Arg2, Regs->Arg3 );
 216                 break;
 217
 218         // Get ACL Value
 219         case SYS_GETACL:
 220                 if( !Syscall_Valid(sizeof(tVFS_ACL), Regs->Arg1) ) {
 221                         err = -EINVAL;
 222                         ret = -1;
 223                         break;
 224                 }
 225                 ret = VFS_GetACL( Regs->Arg1, (void*)Regs->Arg2 );
 226                 break;
 227
 228         // Read Directory
 229         case SYS_READDIR:
 230                 if( !Syscall_Valid(8, Regs->Arg2) ) {
 231                         err = -EINVAL;
 232                         ret = -1;
 233                         break;
 234                 }
 235                 ret = VFS_ReadDir( Regs->Arg1, (void*)Regs->Arg2 );
 236                 break;
 237
 238         // Open a file that is a entry in an open directory
 239         case SYS_OPENCHILD:
 240                 if( !Syscall_ValidString(Regs->Arg2) ) {
 241                         err = -EINVAL;
 242                         ret = -1;
 243                         break;
 244                 }
 245                 ret = VFS_OpenChild( &err, Regs->Arg1, (char*)Regs->Arg2, Regs->Arg3);
 246                 break;
 247
 248         // Change Directory
 249         case SYS_CHDIR:
 250                 if( !Syscall_ValidString(Regs->Arg1) ) {
 251                         err = -EINVAL;
 252                         ret = -1;
 253                         break;
 254                 }
 255                 ret = VFS_ChDir( (void*)Regs->Arg1 );
 256                 break;
 257
 258         // IO Control
 259         case SYS_IOCTL:
 260                 // All sanity checking should be done by the driver
 261                 ret = VFS_IOCtl( Regs->Arg1, Regs->Arg2, (void*)Regs->Arg3 );
 262                 break;
 263
 264         // Mount a filesystem
 265         case SYS_MOUNT:
 266                 // Only root can mount filesystems
 267                 if(Threads_GetUID() != 0) {
 268                         err = -EACCES;
 269                         ret = -1;
 270                         break;
 271                 }
 272                 // Sanity check the paths
 273                 if(!Syscall_ValidString(Regs->Arg1)
 274                 || !Syscall_ValidString(Regs->Arg2)
 275                 || !Syscall_ValidString(Regs->Arg3)
 276                 || !Syscall_ValidString(Regs->Arg4) ) {
 277                         err = -EINVAL;
 278                         ret = -1;
 279                         break;
 280                 }
 281                 ret = VFS_Mount(
 282                         (char*)Regs->Arg1,      // Device
 283                         (char*)Regs->Arg2,      // Mount point
 284                         (char*)Regs->Arg3,      // Filesystem
 285                         (char*)Regs->Arg4       // Options
 286                         );
 287                 break;
 288
 289         // -- Debug
 290         //#if DEBUG_BUILD
 291         case SYS_DEBUG:
 292                 Log((char*)Regs->Arg1,
 293                         Regs->Arg2, Regs->Arg3, Regs->Arg4, Regs->Arg5, Regs->Arg6);
 294                 break;
 295         //#endif
 296
 297         // -- Default (Return Error)
 298         default:
 299                 Warning("SyscallHandler: Unknown System Call %i", Regs->Num);
 300                 if(Regs->Num < NUM_SYSCALLS)
 301                         Warning(" Syscall '%s'", cSYSCALL_NAMES[Regs->Num]);
 302                 err = -ENOSYS;
 303                 ret = -1;
 304                 break;
 305         }
 306
 307         if(err != 0) {
 308                 LOG("ID: %i, Return errno = %i", Regs->Num, err);
 309         }
 310
 311         #if BITS < 64
 312         Regs->Return = ret&0xFFFFFFFF;
 313         Regs->RetHi = ret >> 32;
 314         #else
 315         Regs->Return = ret;
 316         #endif
 317         Regs->Error = err;
 318         #if DEBUG
 319         LOG("err = %i", err);
 320         if(Regs->Num != SYS_EXECVE)
 321                 LEAVE('x', ret);
 322         else
 323                 LOG("Actual %i", ret);
 324         #endif
 325 }
 326
 327 /**
 328  * \fn int Syscall_ValidString(Uint Addr)
 329  * \brief Checks if a memory address contains a valid string
 330  */
 331 int Syscall_ValidString(Uint Addr)
 332 {
 333         // Check if the memory is user memory
 334         if(!MM_IsUser(Addr))    return 0;
 335
 336         return CheckString( (char*)Addr );
 337 }
 338
 339 /**
 340  * \fn int Syscall_Valid(int Size, Uint Addr)
 341  * \brief Checks if a memory address is valid
 342  */
 343 int Syscall_Valid(int Size, Uint Addr)
 344 {
 345         if(!MM_IsUser(Addr))    return 0;
 346
 347         return CheckMem( (void*)Addr, Size );
 348 }