コード例 #1
0
/*===========================================================================*
 *				pm_exec					     *
 *===========================================================================*/
int pm_exec(endpoint_t proc_e, vir_bytes path, size_t path_len,
		   vir_bytes frame, size_t frame_len, vir_bytes *pc,
		   vir_bytes *newsp, int user_exec_flags)
{
/* Perform the execve(name, argv, envp) call.  The user library builds a
 * complete stack image, including pointers, args, environ, etc.  The stack
 * is copied to a buffer inside VFS, and then to the new core image.
 */
  int r, slot;
  vir_bytes vsp;
  struct fproc *rfp;
  int extrabase = 0;
  static char mbuf[ARG_MAX];	/* buffer for stack and zeroes */
  struct vfs_exec_info execi;
  int i;
  static char fullpath[PATH_MAX],
  	elf_interpreter[PATH_MAX],
	firstexec[PATH_MAX],
	finalexec[PATH_MAX];
  struct lookup resolve;
  struct fproc *vmfp = &fproc[VM_PROC_NR];
  stackhook_t makestack = NULL;
  static int n;
  n++;
  struct filp *newfilp = NULL;

  lock_exec();
  lock_proc(vmfp, 0);

  /* unset execi values are 0. */
  memset(&execi, 0, sizeof(execi));
  execi.vmfd = -1;

  /* passed from exec() libc code */
  execi.userflags = user_exec_flags;
  execi.args.stack_high = kinfo.user_sp;
  execi.args.stack_size = DEFAULT_STACK_LIMIT;

  okendpt(proc_e, &slot);
  rfp = fp = &fproc[slot];

  lookup_init(&resolve, fullpath, PATH_NOFLAGS, &execi.vmp, &execi.vp);

  resolve.l_vmnt_lock = VMNT_READ;
  resolve.l_vnode_lock = VNODE_READ;

  /* Fetch the stack from the user before destroying the old core image. */
  if (frame_len > ARG_MAX)
	FAILCHECK(ENOMEM); /* stack too big */

  r = sys_datacopy(proc_e, (vir_bytes) frame, SELF, (vir_bytes) mbuf,
		   (size_t) frame_len);
  if (r != OK) { /* can't fetch stack (e.g. bad virtual addr) */
        printf("VFS: pm_exec: sys_datacopy failed\n");
	FAILCHECK(r);
  }

  /* The default is to keep the original user and group IDs */
  execi.args.new_uid = rfp->fp_effuid;
  execi.args.new_gid = rfp->fp_effgid;

  /* Get the exec file name. */
  FAILCHECK(fetch_name(path, path_len, fullpath));
  strlcpy(finalexec, fullpath, PATH_MAX);
  strlcpy(firstexec, fullpath, PATH_MAX);

  /* Get_read_vp will return an opened vn in execi.
   * if necessary it releases the existing vp so we can
   * switch after we find out what's inside the file.
   * It reads the start of the file.
   */
  Get_read_vp(execi, fullpath, 1, 1, &resolve, fp);

  /* If this is a script (i.e. has a #!/interpreter line),
   * retrieve the name of the interpreter and open that
   * executable instead.
   */
  if(is_script(&execi)) {
  	/* patch_stack will add interpreter name and
	 * args to stack and retrieve the new binary
	 * name into fullpath.
	 */
	FAILCHECK(fetch_name(path, path_len, fullpath));
	FAILCHECK(patch_stack(execi.vp, mbuf, &frame_len, fullpath));
	strlcpy(finalexec, fullpath, PATH_MAX);
  	strlcpy(firstexec, fullpath, PATH_MAX);
	Get_read_vp(execi, fullpath, 1, 0, &resolve, fp);
  }

  /* If this is a dynamically linked executable, retrieve
   * the name of that interpreter in elf_interpreter and open that
   * executable instead. But open the current executable in an
   * fd for the current process.
   */
  if(elf_has_interpreter(execi.args.hdr, execi.args.hdr_len,
	elf_interpreter, sizeof(elf_interpreter))) {
	/* Switch the executable vnode to the interpreter */
	execi.is_dyn = 1;

	/* The interpreter (loader) needs an fd to the main program,
	 * which is currently in finalexec
	 */
	if((r = execi.elf_main_fd = common_open(finalexec, O_RDONLY, 0)) < 0) {
		printf("VFS: exec: dynamic: open main exec failed %s (%d)\n",
			fullpath, r);
		FAILCHECK(r);
	}

	/* ld.so is linked at 0, but it can relocate itself; we
	 * want it higher to trap NULL pointer dereferences. 
	 */
	execi.args.load_offset = 0x10000;

	/* Remember it */
	strlcpy(execi.execname, finalexec, PATH_MAX);

	/* The executable we need to execute first (loader)
	 * is in elf_interpreter, and has to be in fullpath to
	 * be looked up
	 */
	strlcpy(fullpath, elf_interpreter, PATH_MAX);
	strlcpy(firstexec, elf_interpreter, PATH_MAX);
	Get_read_vp(execi, fullpath, 0, 0, &resolve, fp);
  }

  /* We also want an FD for VM to mmap() the process in if possible. */
  {
	struct vnode *vp = execi.vp;
	assert(vp);
	if(vp->v_vmnt->m_haspeek && major(vp->v_dev) != MEMORY_MAJOR) {
		int newfd = -1;
		if(get_fd(vmfp, 0, R_BIT, &newfd, &newfilp) == OK) {
			assert(newfd >= 0 && newfd < OPEN_MAX);
			assert(!vmfp->fp_filp[newfd]);
			newfilp->filp_count = 1;
			newfilp->filp_vno = vp;
			newfilp->filp_flags = O_RDONLY;
			FD_SET(newfd, &vmfp->fp_filp_inuse);
			vmfp->fp_filp[newfd] = newfilp;
			/* dup_vnode(vp); */
			execi.vmfd = newfd;
			execi.args.memmap = vfs_memmap;
		}
	}
  }

  /* callback functions and data */
  execi.args.copymem = read_seg;
  execi.args.clearproc = libexec_clearproc_vm_procctl;
  execi.args.clearmem = libexec_clear_sys_memset;
  execi.args.allocmem_prealloc_cleared = libexec_alloc_mmap_prealloc_cleared;
  execi.args.allocmem_prealloc_junk = libexec_alloc_mmap_prealloc_junk;
  execi.args.allocmem_ondemand = libexec_alloc_mmap_ondemand;
  execi.args.opaque = &execi;

  execi.args.proc_e = proc_e;
  execi.args.frame_len = frame_len;
  execi.args.filesize = execi.vp->v_size;

  for (i = 0; exec_loaders[i].load_object != NULL; i++) {
      r = (*exec_loaders[i].load_object)(&execi.args);
      /* Loaded successfully, so no need to try other loaders */
      if (r == OK) { makestack = exec_loaders[i].setup_stack; break; }
  }

  FAILCHECK(r);

  /* Inform PM */
  FAILCHECK(libexec_pm_newexec(proc_e, &execi.args));

  /* Save off PC */
  *pc = execi.args.pc;

  /* call a stack-setup function if this executable type wants it */
  vsp = execi.args.stack_high - frame_len;
  if(makestack) FAILCHECK(makestack(&execi, mbuf, &frame_len, &vsp, &extrabase));

  /* Patch up stack and copy it from VFS to new core image. */
  libexec_patch_ptr(mbuf, vsp + extrabase);
  FAILCHECK(sys_datacopy(SELF, (vir_bytes) mbuf, proc_e, (vir_bytes) vsp,
		   (phys_bytes)frame_len));

  /* Return new stack pointer to caller */
  *newsp = vsp;

  clo_exec(rfp);

  if (execi.args.allow_setuid) {
	/* If after loading the image we're still allowed to run with
	 * setuid or setgid, change credentials now */
	rfp->fp_effuid = execi.args.new_uid;
	rfp->fp_effgid = execi.args.new_gid;
  }

  /* Remember the new name of the process */
  strlcpy(rfp->fp_name, execi.args.progname, PROC_NAME_LEN);

pm_execfinal:
  if(newfilp) unlock_filp(newfilp);
  else if (execi.vp != NULL) {
	unlock_vnode(execi.vp);
	put_vnode(execi.vp);
  }

  if(execi.vmfd >= 0 && !execi.vmfd_used) {
  	if(OK != close_fd(vmfp, execi.vmfd)) {
		printf("VFS: unexpected close fail of vm fd\n");
	}
  }

  unlock_proc(vmfp);
  unlock_exec();

  return(r);
}
コード例 #2
0
ファイル: exec.c プロジェクト: vivekp/minix-1
/*===========================================================================*
 *				pm_exec					     *
 *===========================================================================*/
PUBLIC int pm_exec(int proc_e, char *path, vir_bytes path_len, char *frame,
		   vir_bytes frame_len, vir_bytes *pc)
{
/* Perform the execve(name, argv, envp) call.  The user library builds a
 * complete stack image, including pointers, args, environ, etc.  The stack
 * is copied to a buffer inside VFS, and then to the new core image.
 */
  int r, r1, round, proc_s;
  vir_bytes vsp;
  struct fproc *rfp;
  struct vnode *vp;
  char *cp;
  static char mbuf[ARG_MAX];	/* buffer for stack and zeroes */
  struct exec_info execi;
  int i;

  okendpt(proc_e, &proc_s);
  rfp = fp = &fproc[proc_s];
  who_e = proc_e;
  who_p = proc_s;
  super_user = (fp->fp_effuid == SU_UID ? TRUE : FALSE);   /* su? */

  /* Get the exec file name. */
  if ((r = fetch_name(path, path_len, 0)) != OK) return(r);

  /* Fetch the stack from the user before destroying the old core image. */
  if (frame_len > ARG_MAX) {
		printf("VFS: pm_exec: stack too big\n");
		return(ENOMEM);	/* stack too big */
	}
  r = sys_datacopy(proc_e, (vir_bytes) frame, SELF, (vir_bytes) mbuf,
  		   (phys_bytes) frame_len);
  if (r != OK) { /* can't fetch stack (e.g. bad virtual addr) */
        printf("pm_exec: sys_datacopy failed\n");
        return(r);	
  }

  /* The default is to keep the original user and group IDs */
  execi.new_uid = rfp->fp_effuid;
  execi.new_gid = rfp->fp_effgid;

  for (round= 0; round < 2; round++) {
	/* round = 0 (first attempt), or 1 (interpreted script) */

	/* Save the name of the program */
	(cp= strrchr(user_fullpath, '/')) ? cp++ : (cp= user_fullpath);

	strncpy(execi.progname, cp, PROC_NAME_LEN-1);
	execi.progname[PROC_NAME_LEN-1] = '\0';
	execi.setugid = 0;

	/* Open executable */
	if ((vp = eat_path(PATH_NOFLAGS, fp)) == NULL) return(err_code);
	execi.vp = vp;

	if ((vp->v_mode & I_TYPE) != I_REGULAR) 
		r = ENOEXEC;
	else if ((r1 = forbidden(vp, X_BIT)) != OK)
		r = r1;
	else
		r = req_stat(vp->v_fs_e, vp->v_inode_nr, VFS_PROC_NR,
			     (char *) &(execi.sb), 0, 0);
	if (r != OK) {
	    put_vnode(vp);
	    return(r);
	}

        if (round == 0) {
		/* Deal with setuid/setgid executables */
		if (vp->v_mode & I_SET_UID_BIT) {
			execi.new_uid = vp->v_uid;
			execi.setugid = 1;
		}
		if (vp->v_mode & I_SET_GID_BIT) {
			execi.new_gid = vp->v_gid;
			execi.setugid = 1;
		}
        }

	r = map_header(&execi.hdr, execi.vp);
	if (r != OK) {
	    put_vnode(vp);
	    return(r);
	}

	if (!is_script(execi.hdr, execi.vp->v_size) || round != 0)
		break;

	/* Get fresh copy of the file name. */
	if ((r = fetch_name(path, path_len, 0)) != OK) 
		printf("VFS pm_exec: 2nd fetch_name failed\n");
	else if ((r = patch_stack(vp, mbuf, &frame_len)) != OK) 
		printf("VFS pm_exec: patch_stack failed\n");
	put_vnode(vp);
	if (r != OK) return(r);
  }

  execi.proc_e = proc_e;
  execi.frame_len = frame_len;

  for(i = 0; exec_loaders[i].load_object != NULL; i++) {
      r = (*exec_loaders[i].load_object)(&execi);
      /* Loaded successfully, so no need to try other loaders */
      if (r == OK) break;
  }
  put_vnode(vp);

  /* No exec loader could load the object */
  if (r != OK) {
	return(ENOEXEC);
  }

  /* Save off PC */
  *pc = execi.pc;

  /* Patch up stack and copy it from VFS to new core image. */
  vsp = execi.stack_top;
  vsp -= frame_len;
  patch_ptr(mbuf, vsp);
  if ((r = sys_datacopy(SELF, (vir_bytes) mbuf, proc_e, (vir_bytes) vsp,
		   (phys_bytes)frame_len)) != OK) {
	printf("VFS: datacopy failed (%d) trying to copy to %lu\n", r, vsp);
	return(r);
  }

  if (r != OK) return(r);
  clo_exec(rfp);

  if (execi.setugid) {
	/* If after loading the image we're still allowed to run with
	 * setuid or setgid, change the credentials now */
	rfp->fp_effuid = execi.new_uid;
	rfp->fp_effgid = execi.new_gid;
  }

  /* This child has now exec()ced. */
  rfp->fp_execced = 1;

  return(OK);
}