Kernel/syscalls.c

   1 /*
   2  * AcessOS Microkernel Version
   3  * syscalls.c
   4  */
   5 #define DEBUG   0
   6
   7 #include <common.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      VFS_FInfo(int FD, void *Dest, int MaxACLs);
  29 extern int      VFS_GetACL(int FD, void *Dest);
  30 extern int      VFS_ChDir(char *Dest);
  31 extern int      Threads_SetName(char *NewName);
  32 extern int      Threads_GetPID();
  33 extern int      Threads_GetTID();
  34 extern int      Threads_GetUID();
  35 extern int      Threads_GetGID();
  36
  37 // === PROTOTYPES ===
  38  int    Syscall_ValidString(Uint Addr);
  39  int    Syscall_Valid(int Size, Uint Addr);
  40
  41 // === CODE ===
  42 // TODO: Do sanity checking on arguments, ATM the user can really fuck with the kernel
  43 void SyscallHandler(tSyscallRegs *Regs)
  44 {
  45         Uint64  ret = 0;
  46         Uint    err = 0;
  47
  48         ENTER("iThread iNum", Threads_GetTID(), Regs->Num);
  49         if(Regs->Num < NUM_SYSCALLS)
  50                 LOG("Syscall %s", cSYSCALL_NAMES[Regs->Num]);
  51         LOG("Arg1: 0x%x, Arg2: 0x%x, Arg3: 0x%x, Arg4: 0x%x", Regs->Arg1, Regs->Arg2, Regs->Arg3, Regs->Arg4);
  52         //#endif
  53
  54         switch(Regs->Num)
  55         {
  56         // -- Exit the current thread
  57         case SYS_EXIT:  Threads_Exit(0, Regs->Arg1);    break;
  58
  59         // -- Put the current thread to sleep
  60         case SYS_SLEEP: Threads_Sleep();        break;
  61
  62         // -- Yield current timeslice
  63         case SYS_YIELD: Threads_Yield();        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:        Log("Setting User ID to %i", Regs->Arg1);       break;
 112         case SYS_SETGID:        Log("Setting Group ID to %i", 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                 //NOTE: Uncertain due to length being unknown
 124                 // (Proc_GetMessage should check itself)
 125                 CHECK_NUM_NULLOK(Regs->Arg2, sizeof(Uint)*4);
 126                 // *Source, *Data
 127                 ret = Proc_GetMessage(&err, (Uint*)Regs->Arg1, (void*)Regs->Arg2);
 128                 break;
 129
 130         // -- Set the thread's name
 131         case SYS_SETNAME:
 132                 CHECK_STR_NONULL(Regs->Arg1);
 133                 Threads_SetName( (char*)Regs->Arg1 );
 134                 break;
 135
 136         // ---
 137         // Binary Control
 138         // ---
 139         case SYS_EXECVE:
 140                 CHECK_STR_NONULL(Regs->Arg1);
 141                 //Log(" Regs = {Arg2: %x, Arg3: %x}", Regs->Arg2, Regs->Arg3);
 142                 {
 143                          int    i;
 144                         char    **tmp = (char**)Regs->Arg2;
 145                         // Check ArgV (traverse array checking all string pointers)
 146                         CHECK_NUM_NONULL( tmp, sizeof(char**) );
 147                         //Log("tmp = %p", tmp);
 148                         for(i=0;tmp[i];i++) {
 149                                 CHECK_NUM_NONULL( &tmp[i], sizeof(char*) );
 150                                 CHECK_STR_NONULL( tmp[i] );
 151                         }
 152                         // Check EnvP also
 153                         // - EnvP can be NULL
 154                         if( Regs->Arg3 )
 155                         {
 156                                 tmp = (char**)Regs->Arg3;
 157                                 //Log("tmp = %p", tmp);
 158                                 for(i=0;tmp[i];i++) {
 159                                         CHECK_NUM_NULLOK( &tmp[i], sizeof(char*) );
 160                                         CHECK_STR_NONULL( tmp[i] );
 161                                 }
 162                         }
 163                 }
 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 = -1;
 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(struct s_sysFInfo) + 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         // Change Directory
 239         case SYS_CHDIR:
 240                 if( !Syscall_ValidString(Regs->Arg1) ) {
 241                         err = -EINVAL;
 242                         ret = -1;
 243                         break;
 244                 }
 245                 ret = VFS_ChDir( (void*)Regs->Arg1 );
 246                 break;
 247
 248         // IO Control
 249         case SYS_IOCTL:
 250                 // All sanity checking should be done by the driver
 251                 ret = VFS_IOCtl( Regs->Arg1, Regs->Arg2, (void*)Regs->Arg3 );
 252                 break;
 253
 254         // Mount a filesystem
 255         case SYS_MOUNT:
 256                 // Only root can mount filesystems
 257                 if(Threads_GetUID() != 0) {
 258                         err = -EACCES;
 259                         ret = -1;
 260                         break;
 261                 }
 262                 // Sanity check the paths
 263                 if(!Syscall_ValidString(Regs->Arg1)
 264                 || !Syscall_ValidString(Regs->Arg2)
 265                 || !Syscall_ValidString(Regs->Arg3)
 266                 || !Syscall_ValidString(Regs->Arg4) ) {
 267                         err = -EINVAL;
 268                         ret = -1;
 269                         break;
 270                 }
 271                 ret = VFS_Mount(
 272                         (char*)Regs->Arg1,      // Device
 273                         (char*)Regs->Arg2,      // Mount point
 274                         (char*)Regs->Arg3,      // Filesystem
 275                         (char*)Regs->Arg4       // Options
 276                         );
 277                 break;
 278
 279         // -- Debug
 280         //#if DEBUG_BUILD
 281         case SYS_DEBUG:
 282                 Log((char*)Regs->Arg1,
 283                         Regs->Arg2, Regs->Arg3, Regs->Arg4, Regs->Arg5, Regs->Arg6);
 284                 break;
 285         //#endif
 286
 287         // -- Default (Return Error)
 288         default:
 289                 Warning("SyscallHandler: Unknown System Call %i", Regs->Num);
 290                 if(Regs->Num < NUM_SYSCALLS)
 291                         Warning(" Syscall '%s'", cSYSCALL_NAMES[Regs->Num]);
 292                 err = -ENOSYS;
 293                 ret = -1;
 294                 break;
 295         }
 296
 297         if(err != 0) {
 298                 LOG("ID: %i, Return errno = %i", Regs->Num, err);
 299         }
 300
 301         #if BITS < 64
 302         Regs->Return = ret&0xFFFFFFFF;
 303         Regs->RetHi = ret >> 32;
 304         #else
 305         Regs->Return = ret;
 306         #endif
 307         Regs->Error = err;
 308         #if DEBUG
 309         LOG("err = %i", err);
 310         LEAVE('x', ret);
 311         #endif
 312 }
 313
 314 /**
 315  * \fn int Syscall_ValidString(Uint Addr)
 316  * \brief Checks if a memory address contains a valid string
 317  */
 318 int Syscall_ValidString(Uint Addr)
 319 {
 320         // Check if the memory is user memory
 321         if(!MM_IsUser(Addr))    return 0;
 322
 323         return CheckString( (char*)Addr );
 324 }
 325
 326 /**
 327  * \fn int Syscall_Valid(int Size, Uint Addr)
 328  * \brief Checks if a memory address is valid
 329  */
 330 int Syscall_Valid(int Size, Uint Addr)
 331 {
 332         if(!MM_IsUser(Addr))    return 0;
 333
 334         return CheckMem( (void*)Addr, Size );
 335 }