static int
unexec_doit(
	    int infd,
	    int outfd
	    )
{
	int i;
	struct load_command **the_commands = NULL;
	unsigned the_commands_len;
	struct mach_header the_header;
	int fgrowth = 0;
	int fdatastart;
	int fdatasize;
	int size;
	struct stat st;
	char *buf;
	vm_address_t data_address;
	vm_size_t data_size;
	vm_size_t vmaddr_growth = 0;
	vm_size_t dataseg_vmaddr, dataseg_vmend;

	struct segment_command *segment;

#ifdef NS_TARGET
	unsigned long extreloff = 0;
	unsigned long nextrel = 0;
	struct dysymtab_command *dysymtab;
	struct relocation_info reloc_info;
#endif

	if (!read_macho(infd, &the_header, &the_commands, &the_commands_len)) {
		return (0);
	}


	malloc_cookie = malloc_freezedry ();
	if (!get_data_region(&data_address, &data_size)) {
		return (0);
	}


	/*
	 * DO NOT USE MALLOC IN THIS SECTION
	 */
	{
		/*
		 * Fix offsets
		 */
		for (i = 0; i < the_commands_len; i++) {
			switch (the_commands[i]->cmd) {
			case LC_SEGMENT:
				segment = ((struct segment_command *)
					   the_commands[i]);
				if (strcmp(segment->segname, SEG_DATA) == 0) {
					fdatastart = segment->fileoff;
					fdatasize = segment->filesize;
					fgrowth = (data_size - 
						   segment->filesize);
					segment->vmsize = data_size;
					segment->filesize = data_size;
					dataseg_vmaddr = segment->vmaddr;
					dataseg_vmend = segment->vmaddr + segment->vmsize;
					vmaddr_growth = segment->vmaddr + segment->vmsize;
				} else {
					((struct segment_command *)the_commands[i])->fileoff += fgrowth;
				}

				if( strcmp( segment->segname, SEG_LINKEDIT ) == 0 ) {
					segment->vmaddr = vmaddr_growth;
				}

				break;
			case LC_SYMTAB:
				((struct symtab_command *)
				 the_commands[i])->symoff += fgrowth;
				((struct symtab_command *)
				 the_commands[i])->stroff += fgrowth;
				break;
			case LC_SYMSEG:
				((struct symseg_command *)
				 the_commands[i])->offset += fgrowth;
				break;
#ifdef NS_TARGET
			case LC_DYSYMTAB:
				dysymtab = ((struct dysymtab_command *)the_commands[i]);
				extreloff = dysymtab->extreloff;
				nextrel = dysymtab->nextrel;
				dysymtab->indirectsymoff += fgrowth;
				dysymtab->extreloff += fgrowth;
				break;
#endif
			default:
				break;
			}
		}
		
		/*
		 * Write header
		 */
		if (write(outfd, &the_header, 
			  sizeof(the_header)) != sizeof(the_header)) {
			fatal_unexec("cannot write output file");
			return (0);
		}
		
		/*
		 * Write commands
		 */
		for (i = 0; i < the_commands_len; i++) {
			if (write(outfd, the_commands[i], 
				  the_commands[i]->cmdsize) != 
			    the_commands[i]->cmdsize) {
			  	fatal_unexec("cannot write output file");
				return (0);
			}
		}
		
		/*
		 * Write original text
		 */
		if (lseek(infd, the_header.sizeofcmds + sizeof(the_header), 
			  L_SET) < 0) {
		  	fatal_unexec("cannot seek input file");
			return (0);
		}
		size = fdatastart - (sizeof(the_header) + 
				     the_header.sizeofcmds);
		buf = my_malloc(size);
		if (read(infd, buf, size) != size) {
			my_free(buf, size);
		  	fatal_unexec("cannot read input file");
		}
		if (write(outfd, buf, size) != size) {
			my_free(buf, size);
			fatal_unexec("cannot write output file");
			return (0);
		}
		my_free(buf, size);
		
		
		/*
		 * Write new data
		 */
		if (write(outfd, (char *)data_address, 
			  data_size) != data_size) {
			fatal_unexec("cannot write output file");
			return (0);
		}
		
	}

	/*
	 * OKAY TO USE MALLOC NOW
	 */

	/*
	 * Write rest of file
	 */
	fstat(infd, &st);
	if (lseek(infd, fdatasize, L_INCR) < 0) {
		fatal_unexec("cannot seek input file");
		return (0);
	}
	size = st.st_size - lseek(infd, 0, L_INCR);

	buf = malloc(size);
	if (read(infd, buf, size) != size) {
		free(buf);
		fatal_unexec("cannot read input file");
		return (0);
	}
	if (write(outfd, buf, size) != size) {
		free(buf);
		fatal_unexec("cannot write output file");
		return (0);
	}
	free(buf);

#ifdef NS_TARGET
        /*
         * Fix up relocation entries in the data segment.
         */

	if (lseek(infd, extreloff, L_SET) < 0) {
		fatal_unexec("cannot seek input file");
		return (0);
	}
        
        for (i = 0; i < nextrel; i++)
        {
          long zeroval = 0;

          if (read(infd, &reloc_info, sizeof (reloc_info)) != sizeof (reloc_info)) {
            fatal_unexec("cannot read input file");
            return (0);
          }
          if (reloc_info.r_address >= dataseg_vmaddr && reloc_info.r_address < dataseg_vmend)
          {
            if (lseek (outfd, fdatastart + reloc_info.r_address - dataseg_vmaddr, L_SET) < 0 ) {
              fatal_unexec("cannot seek input file");
              return (0);
            }
            switch (reloc_info.r_length) {
              case 0:
		if (write(outfd, &zeroval, 1) != 1) {
			fatal_unexec("cannot write output file");
			return (0);
		}
                break;
              case 1:
		if (write(outfd, &zeroval, 2) != 2) {
			fatal_unexec("cannot write output file");
			return (0);
		}
                break;
              case 2:
		if (write(outfd, &zeroval, 4) != 4) {
			fatal_unexec("cannot write output file");
			return (0);
		}
                break;
            }
          }
        }
#endif

	return (1);
}
Beispiel #2
0
static int
unexec_doit(
	    int infd,
	    int outfd
	    )
{
	int i;
	struct load_command **the_commands = NULL;
	unsigned the_commands_len;
	struct mach_header the_header;
	int fgrowth;
	int fdatastart;
	int fdatasize;
	int size;
	struct stat st;
	char *buf;
	vm_address_t data_address;
	vm_size_t data_size;

	struct segment_command *segment;

	if (!read_macho(infd, &the_header, &the_commands, &the_commands_len)) {
		return (0);
	}

	malloc_cookie = malloc_freezedry();

	if (!get_data_region(&data_address, &data_size)) {
		return (0);
	}


	/*
	 * DO NOT USE MALLOC IN THIS SECTION
	 */
	{
		/*
		 * Fix offsets
		 */
		for (i = 0; i < the_commands_len; i++) {
			switch (the_commands[i]->cmd) {
			case LC_SEGMENT:
				segment = ((struct segment_command *)
					   the_commands[i]);
				if (strcmp(segment->segname, SEG_DATA) == 0) {
					fdatastart = segment->fileoff;
					fdatasize = segment->filesize;
					fgrowth = (data_size - 
						   segment->filesize);
					segment->vmsize = data_size;
					segment->filesize = data_size;
				}
				break;
			case LC_SYMTAB:
				((struct symtab_command *)
				 the_commands[i])->symoff += fgrowth;
				((struct symtab_command *)
				 the_commands[i])->stroff += fgrowth;
				break;
			case LC_SYMSEG:
				((struct symseg_command *)
				 the_commands[i])->offset += fgrowth;
				break;
			default:
				break;
			}
		}
		
		/*
		 * Write header
		 */
		if (write(outfd, &the_header, 
			  sizeof(the_header)) != sizeof(the_header)) {
			fatal_unexec("cannot write output file");
			return (0);
		}
		
		/*
		 * Write commands
		 */
		for (i = 0; i < the_commands_len; i++) {
			if (write(outfd, the_commands[i], 
				  the_commands[i]->cmdsize) != 
			    the_commands[i]->cmdsize) {
			  	fatal_unexec("cannot write output file");
				return (0);
			}
		}
		
		/*
		 * Write original text
		 * We're already positioned at the beginning of the text
		 * segment, so all we need to do is to copy the bytes.
		 */
		size = fdatastart - (sizeof(the_header) + 
				     the_header.sizeofcmds);
		buf = my_malloc(size);
		if (read(infd, buf, size) != size) {
			my_free(buf, size);
		  	fatal_unexec("cannot read input file");
		}
		if (write(outfd, buf, size) != size) {
			my_free(buf, size);
			fatal_unexec("cannot write output file");
			return (0);
		}
		my_free(buf, size);
		
		
		/*
		 * Write new data
		 */
		if (write(outfd, (char *)data_address, 
			  data_size) != data_size) {
			fatal_unexec("cannot write output file");
			return (0);
		}
		
	}

	/*
	 * OKAY TO USE MALLOC NOW
	 */

	/*
	 * Write rest of file
	 */
	fstat(infd, &st);
	if (lseek(infd, fdatasize, L_INCR) < 0) {
		fatal_unexec("cannot seek input file");
		return (0);
	}
	size = st.st_size - lseek(infd, 0, L_INCR);

	buf = malloc(size);
	if (read(infd, buf, size) != size) {
		free(buf);
		fatal_unexec("cannot read input file");
		return (0);
	}
	if (write(outfd, buf, size) != size) {
		free(buf);
		fatal_unexec("cannot write output file");
		return (0);
	}
	free(buf);
	return (1);
}