439 lines
14 KiB
C
439 lines
14 KiB
C
/* Copyright (C) 1991-2018 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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#include <errno.h>
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#include <unistd.h>
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#include <fcntl.h>
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#include <limits.h>
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#include <stdlib.h>
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#include <string.h>
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#include <hurd.h>
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#include <hurd/fd.h>
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#include <hurd/signal.h>
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#include <hurd/id.h>
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#include <assert.h>
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#include <argz.h>
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/* Overlay TASK, executing FILE with arguments ARGV and environment ENVP.
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If TASK == mach_task_self (), some ports are dealloc'd by the exec server.
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ARGV and ENVP are terminated by NULL pointers.
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Deprecated: use _hurd_exec_paths instead. */
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error_t
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_hurd_exec (task_t task, file_t file,
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char *const argv[], char *const envp[])
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{
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return _hurd_exec_paths (task, file, NULL, NULL, argv, envp);
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}
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link_warning (_hurd_exec,
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"_hurd_exec is deprecated, use _hurd_exec_paths instead");
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/* Overlay TASK, executing FILE with arguments ARGV and environment ENVP.
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If TASK == mach_task_self (), some ports are dealloc'd by the exec server.
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ARGV and ENVP are terminated by NULL pointers. PATH is the relative path to
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FILE and ABSPATH is the absolute path to FILE. Passing NULL, though possible,
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should be avoided, since then the exec server may not know the path to
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FILE if FILE is a script, and will then pass /dev/fd/N to the
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interpreter. */
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error_t
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_hurd_exec_paths (task_t task, file_t file,
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const char *path, const char *abspath,
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char *const argv[], char *const envp[])
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{
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error_t err;
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char *args, *env;
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size_t argslen, envlen;
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int ints[INIT_INT_MAX];
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mach_port_t ports[_hurd_nports];
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struct hurd_userlink ulink_ports[_hurd_nports];
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inline void free_port (unsigned int i)
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{
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_hurd_port_free (&_hurd_ports[i], &ulink_ports[i], ports[i]);
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}
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file_t *dtable;
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unsigned int dtablesize, i;
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struct hurd_port **dtable_cells;
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struct hurd_userlink *ulink_dtable;
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struct hurd_sigstate *ss;
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mach_port_t *please_dealloc, *pdp;
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int reauth = 0;
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/* XXX needs to be hurdmalloc XXX */
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if (argv == NULL)
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args = NULL, argslen = 0;
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else if (err = __argz_create (argv, &args, &argslen))
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return err;
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if (envp == NULL)
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env = NULL, envlen = 0;
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else if (err = __argz_create (envp, &env, &envlen))
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goto outargs;
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/* Load up the ports to give to the new program. */
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for (i = 0; i < _hurd_nports; ++i)
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if (i == INIT_PORT_PROC && task != __mach_task_self ())
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{
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/* This is another task, so we need to ask the proc server
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for the right proc server port for it. */
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if (err = __USEPORT (PROC, __proc_task2proc (port, task, &ports[i])))
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{
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while (--i > 0)
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free_port (i);
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goto outenv;
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}
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}
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else
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ports[i] = _hurd_port_get (&_hurd_ports[i], &ulink_ports[i]);
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/* Load up the ints to give the new program. */
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for (i = 0; i < INIT_INT_MAX; ++i)
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switch (i)
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{
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case INIT_UMASK:
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ints[i] = _hurd_umask;
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break;
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case INIT_SIGMASK:
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case INIT_SIGIGN:
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case INIT_SIGPENDING:
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/* We will set these all below. */
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break;
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case INIT_TRACEMASK:
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ints[i] = _hurdsig_traced;
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break;
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default:
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ints[i] = 0;
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}
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ss = _hurd_self_sigstate ();
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assert (! __spin_lock_locked (&ss->critical_section_lock));
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__spin_lock (&ss->critical_section_lock);
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__spin_lock (&ss->lock);
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ints[INIT_SIGMASK] = ss->blocked;
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ints[INIT_SIGPENDING] = ss->pending;
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ints[INIT_SIGIGN] = 0;
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for (i = 1; i < NSIG; ++i)
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if (ss->actions[i].sa_handler == SIG_IGN)
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ints[INIT_SIGIGN] |= __sigmask (i);
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/* We hold the sigstate lock until the exec has failed so that no signal
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can arrive between when we pack the blocked and ignored signals, and
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when the exec actually happens. A signal handler could change what
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signals are blocked and ignored. Either the change will be reflected
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in the exec, or the signal will never be delivered. Setting the
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critical section flag avoids anything we call trying to acquire the
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sigstate lock. */
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__spin_unlock (&ss->lock);
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/* Pack up the descriptor table to give the new program. */
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__mutex_lock (&_hurd_dtable_lock);
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dtablesize = _hurd_dtable ? _hurd_dtablesize : _hurd_init_dtablesize;
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if (task == __mach_task_self ())
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/* Request the exec server to deallocate some ports from us if the exec
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succeeds. The init ports and descriptor ports will arrive in the
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new program's exec_startup message. If we failed to deallocate
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them, the new program would have duplicate user references for them.
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But we cannot deallocate them ourselves, because we must still have
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them after a failed exec call. */
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please_dealloc = __alloca ((_hurd_nports + 3 + (3 * dtablesize))
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* sizeof (mach_port_t));
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else
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please_dealloc = NULL;
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pdp = please_dealloc;
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if (_hurd_dtable != NULL)
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{
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dtable = __alloca (dtablesize * sizeof (dtable[0]));
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ulink_dtable = __alloca (dtablesize * sizeof (ulink_dtable[0]));
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dtable_cells = __alloca (dtablesize * sizeof (dtable_cells[0]));
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for (i = 0; i < dtablesize; ++i)
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{
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struct hurd_fd *const d = _hurd_dtable[i];
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if (d == NULL)
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{
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dtable[i] = MACH_PORT_NULL;
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continue;
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}
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__spin_lock (&d->port.lock);
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if (d->flags & FD_CLOEXEC)
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{
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/* This descriptor is marked to be closed on exec.
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So don't pass it to the new program. */
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dtable[i] = MACH_PORT_NULL;
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if (pdp && d->port.port != MACH_PORT_NULL)
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{
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/* We still need to deallocate the ports. */
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*pdp++ = d->port.port;
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if (d->ctty.port != MACH_PORT_NULL)
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*pdp++ = d->ctty.port;
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}
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__spin_unlock (&d->port.lock);
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}
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else
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{
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if (pdp && d->ctty.port != MACH_PORT_NULL)
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/* All the elements of DTABLE are added to PLEASE_DEALLOC
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below, so we needn't add the port itself.
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But we must deallocate the ctty port as well as
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the normal port that got installed in DTABLE[I]. */
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*pdp++ = d->ctty.port;
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dtable[i] = _hurd_port_locked_get (&d->port, &ulink_dtable[i]);
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dtable_cells[i] = &d->port;
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}
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}
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}
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else
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{
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dtable = _hurd_init_dtable;
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ulink_dtable = NULL;
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dtable_cells = NULL;
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}
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/* Prune trailing null ports from the descriptor table. */
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while (dtablesize > 0 && dtable[dtablesize - 1] == MACH_PORT_NULL)
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--dtablesize;
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/* See if we need to diddle the auth port of the new program.
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The purpose of this is to get the effect setting the saved-set UID and
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GID to the respective effective IDs after the exec, as POSIX.1 requires.
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Note that we don't reauthenticate with the proc server; that would be a
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no-op since it only keeps track of the effective UIDs, and if it did
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keep track of the available IDs we would have the problem that we'd be
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changing the IDs before the exec and have to change them back after a
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failure. Arguably we could skip all the reauthentications because the
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available IDs have no bearing on any filesystem. But the conservative
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approach is to reauthenticate all the io ports so that no state anywhere
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reflects that our whole ID set differs from what we've set it to. */
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__mutex_lock (&_hurd_id.lock);
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err = _hurd_check_ids ();
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if (err == 0 && ((_hurd_id.aux.nuids >= 2 && _hurd_id.gen.nuids >= 1
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&& _hurd_id.aux.uids[1] != _hurd_id.gen.uids[0])
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|| (_hurd_id.aux.ngids >= 2 && _hurd_id.gen.ngids >= 1
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&& _hurd_id.aux.gids[1] != _hurd_id.gen.gids[0])))
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{
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/* We have euid != svuid or egid != svgid. POSIX.1 says that exec
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sets svuid = euid and svgid = egid. So we must get a new auth
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port and reauthenticate everything with it. We'll pass the new
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ports in file_exec_paths instead of our own ports. */
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auth_t newauth;
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_hurd_id.aux.uids[1] = _hurd_id.gen.uids[0];
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_hurd_id.aux.gids[1] = _hurd_id.gen.gids[0];
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_hurd_id.valid = 0;
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if (_hurd_id.rid_auth != MACH_PORT_NULL)
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{
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__mach_port_deallocate (__mach_task_self (), _hurd_id.rid_auth);
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_hurd_id.rid_auth = MACH_PORT_NULL;
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}
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err = __auth_makeauth (ports[INIT_PORT_AUTH],
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NULL, MACH_MSG_TYPE_COPY_SEND, 0,
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_hurd_id.gen.uids, _hurd_id.gen.nuids,
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_hurd_id.aux.uids, _hurd_id.aux.nuids,
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_hurd_id.gen.gids, _hurd_id.gen.ngids,
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_hurd_id.aux.gids, _hurd_id.aux.ngids,
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&newauth);
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if (err == 0)
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{
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/* Now we have to reauthenticate the ports with this new ID.
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*/
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inline error_t reauth_io (io_t port, io_t *newport)
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{
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mach_port_t ref = __mach_reply_port ();
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*newport = MACH_PORT_NULL;
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error_t err = __io_reauthenticate (port,
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ref, MACH_MSG_TYPE_MAKE_SEND);
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if (!err)
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err = __auth_user_authenticate (newauth,
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ref, MACH_MSG_TYPE_MAKE_SEND,
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newport);
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__mach_port_destroy (__mach_task_self (), ref);
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return err;
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}
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inline void reauth_port (unsigned int idx)
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{
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io_t newport;
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err = reauth_io (ports[idx], &newport) ?: err;
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if (pdp)
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*pdp++ = ports[idx]; /* XXX presumed still in _hurd_ports */
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free_port (idx);
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ports[idx] = newport;
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}
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if (pdp)
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*pdp++ = ports[INIT_PORT_AUTH];
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free_port (INIT_PORT_AUTH);
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ports[INIT_PORT_AUTH] = newauth;
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reauth_port (INIT_PORT_CRDIR);
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reauth_port (INIT_PORT_CWDIR);
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if (!err)
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{
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/* Now we'll reauthenticate each file descriptor. */
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if (ulink_dtable == NULL)
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{
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assert (dtable == _hurd_init_dtable);
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dtable = __alloca (dtablesize * sizeof (dtable[0]));
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for (i = 0; i < dtablesize; ++i)
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if (_hurd_init_dtable[i] != MACH_PORT_NULL)
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{
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if (pdp)
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*pdp++ = _hurd_init_dtable[i];
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err = reauth_io (_hurd_init_dtable[i], &dtable[i]);
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if (err)
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{
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while (++i < dtablesize)
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dtable[i] = MACH_PORT_NULL;
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break;
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}
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}
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else
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dtable[i] = MACH_PORT_NULL;
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}
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else
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{
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if (pdp)
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{
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/* Ask to deallocate all the old fd ports,
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since we will have new ones in DTABLE. */
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memcpy (pdp, dtable, dtablesize * sizeof pdp[0]);
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pdp += dtablesize;
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}
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for (i = 0; i < dtablesize; ++i)
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if (dtable[i] != MACH_PORT_NULL)
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{
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io_t newport;
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err = reauth_io (dtable[i], &newport);
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_hurd_port_free (dtable_cells[i], &ulink_dtable[i],
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dtable[i]);
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dtable[i] = newport;
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if (err)
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{
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while (++i < dtablesize)
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_hurd_port_free (dtable_cells[i],
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&ulink_dtable[i], dtable[i]);
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break;
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}
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}
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ulink_dtable = NULL;
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dtable_cells = NULL;
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}
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}
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}
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reauth = 1;
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}
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__mutex_unlock (&_hurd_id.lock);
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/* The information is all set up now. Try to exec the file. */
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if (!err)
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{
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int flags;
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if (pdp)
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{
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/* Request the exec server to deallocate some ports from us if
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the exec succeeds. The init ports and descriptor ports will
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arrive in the new program's exec_startup message. If we
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failed to deallocate them, the new program would have
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duplicate user references for them. But we cannot deallocate
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them ourselves, because we must still have them after a failed
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exec call. */
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for (i = 0; i < _hurd_nports; ++i)
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*pdp++ = ports[i];
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for (i = 0; i < dtablesize; ++i)
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*pdp++ = dtable[i];
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}
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flags = 0;
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#ifdef EXEC_SIGTRAP
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/* PTRACE_TRACEME sets all bits in _hurdsig_traced, which is
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propagated through exec by INIT_TRACEMASK, so this checks if
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PTRACE_TRACEME has been called in this process in any of its
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current or prior lives. */
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if (__sigismember (&_hurdsig_traced, SIGKILL))
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flags |= EXEC_SIGTRAP;
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#endif
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err = __file_exec_paths (file, task, flags,
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path ? path : "",
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abspath ? abspath : "",
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args, argslen, env, envlen,
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dtable, MACH_MSG_TYPE_COPY_SEND, dtablesize,
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ports, MACH_MSG_TYPE_COPY_SEND,
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_hurd_nports,
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ints, INIT_INT_MAX,
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please_dealloc, pdp - please_dealloc,
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&_hurd_msgport,
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task == __mach_task_self () ? 1 : 0);
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/* Fall back for backwards compatibility. This can just be removed
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when __file_exec goes away. */
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if (err == MIG_BAD_ID)
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err = __file_exec (file, task, flags,
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args, argslen, env, envlen,
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dtable, MACH_MSG_TYPE_COPY_SEND, dtablesize,
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ports, MACH_MSG_TYPE_COPY_SEND, _hurd_nports,
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ints, INIT_INT_MAX,
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please_dealloc, pdp - please_dealloc,
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&_hurd_msgport,
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task == __mach_task_self () ? 1 : 0);
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}
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/* Release references to the standard ports. */
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for (i = 0; i < _hurd_nports; ++i)
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if ((i == INIT_PORT_PROC && task != __mach_task_self ())
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|| (reauth && (i == INIT_PORT_AUTH
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|| i == INIT_PORT_CRDIR || i == INIT_PORT_CWDIR)))
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__mach_port_deallocate (__mach_task_self (), ports[i]);
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else
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free_port (i);
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/* Release references to the file descriptor ports. */
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if (ulink_dtable != NULL)
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{
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for (i = 0; i < dtablesize; ++i)
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if (dtable[i] != MACH_PORT_NULL)
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_hurd_port_free (dtable_cells[i], &ulink_dtable[i], dtable[i]);
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}
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else if (dtable && dtable != _hurd_init_dtable)
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for (i = 0; i < dtablesize; ++i)
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__mach_port_deallocate (__mach_task_self (), dtable[i]);
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/* Release lock on the file descriptor table. */
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__mutex_unlock (&_hurd_dtable_lock);
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/* Safe to let signals happen now. */
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_hurd_critical_section_unlock (ss);
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outargs:
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free (args);
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outenv:
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free (env);
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return err;
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}
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libc_hidden_def (_hurd_exec_paths)
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