mirror of
https://github.com/UberGames/lilium-voyager.git
synced 2024-12-13 05:31:29 +00:00
use mmap to allocate memory for generated code to be able to set PROT_EXEC
This commit is contained in:
parent
87ce505868
commit
39f2e449b6
3 changed files with 49 additions and 50 deletions
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@ -615,6 +615,9 @@ VM_Free
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*/
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void VM_Free( vm_t *vm ) {
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if(vm->destroy)
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vm->destroy(vm);
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if ( vm->dllHandle ) {
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Sys_UnloadDll( vm->dllHandle );
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Com_Memset( vm, 0, sizeof( *vm ) );
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@ -31,6 +31,14 @@ Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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#include <sys/mman.h> // for PROT_ stuff
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#endif
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/* need this on NX enabled systems (i386 with PAE kernel or
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* noexec32=on x86_64) */
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#ifdef __linux__
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#define VM_X86_MMAP
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#endif
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static void VM_Destroy_Compiled(vm_t* self);
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/*
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eax scratch
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@ -1069,34 +1077,40 @@ void VM_Compile( vm_t *vm, vmHeader_t *header ) {
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// copy to an exact size buffer on the hunk
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vm->codeLength = compiledOfs;
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vm->codeBase = Hunk_Alloc( compiledOfs, h_low );
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#ifdef VM_X86_MMAP
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vm->codeBase = mmap(NULL, compiledOfs, PROT_WRITE, MAP_SHARED|MAP_ANONYMOUS, -1, 0);
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if(vm->codeBase == (void*)-1)
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Com_Error(ERR_DROP, "VM_CompileX86: can't mmap memory");
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#else
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vm->codeBase = malloc(compiledOfs);
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#endif
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Com_Memcpy( vm->codeBase, buf, compiledOfs );
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#ifdef VM_X86_MMAP
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if(mprotect(vm->codeBase, compiledOfs, PROT_READ|PROT_EXEC))
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Com_Error(ERR_DROP, "VM_CompileX86: mprotect failed");
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#endif
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Z_Free( buf );
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Z_Free( jused );
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Com_Printf( "VM file %s compiled to %i bytes of code\n", vm->name, compiledOfs );
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vm->destroy = VM_Destroy_Compiled;
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// offset all the instruction pointers for the new location
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for ( i = 0 ; i < header->instructionCount ; i++ ) {
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vm->instructionPointers[i] += (int)vm->codeBase;
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}
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}
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#if 0 // ndef _WIN32
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// Must make the newly generated code executable
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{
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int r;
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unsigned long addr;
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int psize = getpagesize();
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addr = ((int)vm->codeBase & ~(psize-1)) - psize;
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r = mprotect((char*)addr, vm->codeLength + (int)vm->codeBase - addr + psize,
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PROT_READ | PROT_WRITE | PROT_EXEC );
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if (r < 0)
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Com_Error( ERR_FATAL, "mprotect failed to change PROT_EXEC" );
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}
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void VM_Destroy_Compiled(vm_t* self)
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{
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#ifdef VM_X86_MMAP
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munmap(self->codeBase, self->codeLength);
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#else
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free(self->codeBase);
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#endif
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}
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/*
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@ -39,6 +39,8 @@ static FILE* qdasmout;
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#define Dfprintf(args...)
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#endif
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static void VM_Destroy_Compiled(vm_t* self);
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/*
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eax scratch
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@ -308,10 +310,8 @@ out:
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static int doas(char* in, char* out, unsigned char** compiledcode)
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{
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char* buf;
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char* mem;
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size_t size = -1, allocsize;
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int ps;
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unsigned char* mem;
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size_t size = -1;
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pid_t pid;
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Com_Printf("running assembler < %s > %s\n", in, out);
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@ -358,42 +358,16 @@ static int doas(char* in, char* out, unsigned char** compiledcode)
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Com_Printf("done\n");
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mem = mmapfile(out, &size);
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mem = (unsigned char*)mmapfile(out, &size);
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if(!mem)
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{
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Com_Printf(S_COLOR_RED "can't mmap object file %s: %s\n", out, strerror(errno));
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return -1;
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}
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ps = sysconf(_SC_PAGE_SIZE);
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if(ps == -1)
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{
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Com_Printf(S_COLOR_RED "can't determine page size: %s\n", strerror(errno));
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return -1;
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}
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*compiledcode = mem;
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--ps;
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allocsize = (size+ps)&~ps;
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buf = Hunk_Alloc(allocsize, h_high);
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buf = (void*)(((unsigned long)buf+ps)&~ps);
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memcpy(buf, mem, size);
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munmap(mem, 0);
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if((*compiledcode = (unsigned char*)buf))
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{
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// need to be able to exec code
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if(mprotect(buf, allocsize, PROT_READ|PROT_WRITE|PROT_EXEC) == -1)
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{
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Com_Error(ERR_FATAL, "mprotect failed on %p+%x: %s\n", buf, allocsize, strerror(errno));
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}
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return size;
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}
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return -1;
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return size;
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}
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static void block_copy_vm(unsigned dest, unsigned src, unsigned count)
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@ -897,6 +871,8 @@ void VM_Compile( vm_t *vm, vmHeader_t *header ) {
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vm->codeBase = compiledcode; // remember to skip ELF header!
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vm->codeLength = compiledsize;
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vm->destroy = VM_Destroy_Compiled;
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entryPoint = getentrypoint(vm);
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@ -930,6 +906,12 @@ out:
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}
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}
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void VM_Destroy_Compiled(vm_t* self)
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{
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munmap(self->codeBase, self->codeLength);
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}
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/*
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==============
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VM_CallCompiled
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