libvirt/tools/virt-login-shell.c
Eric Blake c72e76c3d9 util: make it easier to grab only regular process exit
Right now, a caller waiting for a child process either requires
the child to have status 0, or must use WIFEXITED() and friends
itself.  But in many cases, we want the middle ground of treating
fatal signals as an error, and directly accessing the normal exit
value without having to use WEXITSTATUS(), in order to easily
detect an expected non-zero exit status.  This adds the middle
ground to the low-level virProcessWait; the next patch will add
it to virCommand.

* src/util/virprocess.h (virProcessWait): Alter signature.
* src/util/virprocess.c (virProcessWait): Add parameter.
(virProcessRunInMountNamespace): Adjust caller.
* src/util/vircommand.c (virCommandWait): Likewise.
* src/util/virfile.c (virFileAccessibleAs): Likewise.
* src/lxc/lxc_container.c (lxcContainerHasReboot)
(lxcContainerAvailable): Likewise.
* daemon/libvirtd.c (daemonForkIntoBackground): Likewise.
* tools/virt-login-shell.c (main): Likewise.
* tools/virsh-domain.c (cmdLxcEnterNamespace): Likewise.
* tests/testutils.c (virtTestCaptureProgramOutput): Likewise.
* tests/commandtest.c (test23): Likewise.

Signed-off-by: Eric Blake <eblake@redhat.com>
2014-03-03 12:40:31 -07:00

389 lines
10 KiB
C

/*
* virt-login-shell.c: a shell to connect to a container
*
* Copyright (C) 2013-2014 Red Hat, Inc.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library. If not, see
* <http://www.gnu.org/licenses/>.
*
* Daniel Walsh <dwalsh@redhat.com>
*/
#include <config.h>
#include <stdarg.h>
#include <getopt.h>
#include <stdio.h>
#include <errno.h>
#include <stdlib.h>
#include <fnmatch.h>
#include <locale.h>
#include "internal.h"
#include "virerror.h"
#include "virconf.h"
#include "virutil.h"
#include "virfile.h"
#include "virprocess.h"
#include "configmake.h"
#include "virstring.h"
#include "viralloc.h"
#include "vircommand.h"
#define VIR_FROM_THIS VIR_FROM_NONE
static ssize_t nfdlist;
static int *fdlist;
static const char *conf_file = SYSCONFDIR "/libvirt/virt-login-shell.conf";
static void virLoginShellFini(virConnectPtr conn, virDomainPtr dom)
{
size_t i;
for (i = 0; i < nfdlist; i++)
VIR_FORCE_CLOSE(fdlist[i]);
VIR_FREE(fdlist);
nfdlist = 0;
if (dom)
virDomainFree(dom);
if (conn)
virConnectClose(conn);
}
static int virLoginShellAllowedUser(virConfPtr conf,
const char *name,
gid_t *groups)
{
virConfValuePtr p;
int ret = -1;
char *ptr = NULL;
size_t i;
char *gname = NULL;
p = virConfGetValue(conf, "allowed_users");
if (p && p->type == VIR_CONF_LIST) {
virConfValuePtr pp;
/* Calc length and check items */
for (pp = p->list; pp; pp = pp->next) {
if (pp->type != VIR_CONF_STRING) {
virReportSystemError(EINVAL, "%s",
_("shell must be a list of strings"));
goto cleanup;
} else {
/*
If string begins with a % this indicates a linux group.
Check to see if the user is in the Linux Group.
*/
if (pp->str[0] == '%') {
ptr = &pp->str[1];
if (!*ptr)
continue;
for (i = 0; groups[i]; i++) {
if (!(gname = virGetGroupName(groups[i])))
continue;
if (fnmatch(ptr, gname, 0) == 0) {
ret = 0;
goto cleanup;
}
VIR_FREE(gname);
}
continue;
}
if (fnmatch(pp->str, name, 0) == 0) {
ret = 0;
goto cleanup;
}
}
}
}
virReportSystemError(EPERM,
_("%s not matched against 'allowed_users' in %s"),
name, conf_file);
cleanup:
VIR_FREE(gname);
return ret;
}
static char **virLoginShellGetShellArgv(virConfPtr conf)
{
size_t i;
char **shargv = NULL;
virConfValuePtr p;
p = virConfGetValue(conf, "shell");
if (!p)
return virStringSplit("/bin/sh -l", " ", 3);
if (p->type == VIR_CONF_LIST) {
size_t len;
virConfValuePtr pp;
/* Calc length and check items */
for (len = 0, pp = p->list; pp; len++, pp = pp->next) {
if (pp->type != VIR_CONF_STRING) {
virReportSystemError(EINVAL, "%s",
_("shell must be a list of strings"));
goto error;
}
}
if (VIR_ALLOC_N(shargv, len + 1) < 0)
goto error;
for (i = 0, pp = p->list; pp; i++, pp = pp->next) {
if (VIR_STRDUP(shargv[i], pp->str) < 0)
goto error;
}
}
return shargv;
error:
virStringFreeList(shargv);
return NULL;
}
static char *progname;
/*
* Print usage
*/
static void
usage(void)
{
fprintf(stdout,
_("\n"
"Usage:\n"
" %s [option]\n\n"
"Options:\n"
" -h | --help Display program help\n"
" -V | --version Display program version\n"
"\n"
"libvirt login shell\n"),
progname);
return;
}
/* Display version information. */
static void
show_version(void)
{
printf("%s (%s) %s\n", progname, PACKAGE_NAME, PACKAGE_VERSION);
}
int
main(int argc, char **argv)
{
virConfPtr conf = NULL;
const char *login_shell_path = conf_file;
pid_t cpid;
int ret = EXIT_FAILURE;
int status;
int status2;
uid_t uid = getuid();
gid_t gid = getgid();
char *name = NULL;
char **shargv = NULL;
virSecurityModelPtr secmodel = NULL;
virSecurityLabelPtr seclabel = NULL;
virDomainPtr dom = NULL;
virConnectPtr conn = NULL;
char *homedir = NULL;
int arg;
int longindex = -1;
int ngroups;
gid_t *groups = NULL;
struct option opt[] = {
{"help", no_argument, NULL, 'h'},
{"version", optional_argument, NULL, 'V'},
{NULL, 0, NULL, 0}
};
if (virInitialize() < 0) {
fprintf(stderr, _("Failed to initialize libvirt Error Handling"));
return EXIT_FAILURE;
}
setenv("PATH", "/bin:/usr/bin", 1);
virSetErrorFunc(NULL, NULL);
virSetErrorLogPriorityFunc(NULL);
progname = argv[0];
if (!setlocale(LC_ALL, "")) {
perror("setlocale");
/* failure to setup locale is not fatal */
}
if (!bindtextdomain(PACKAGE, LOCALEDIR)) {
perror("bindtextdomain");
return ret;
}
if (!textdomain(PACKAGE)) {
perror("textdomain");
return ret;
}
while ((arg = getopt_long(argc, argv, "hV", opt, &longindex)) != -1) {
switch (arg) {
case 'h':
usage();
exit(EXIT_SUCCESS);
case 'V':
show_version();
exit(EXIT_SUCCESS);
case '?':
default:
usage();
exit(EXIT_FAILURE);
}
}
if (argc > optind) {
virReportSystemError(EINVAL, _("%s takes no options"), progname);
goto cleanup;
}
if (uid == 0) {
virReportSystemError(EPERM, _("%s must be run by non root users"),
progname);
goto cleanup;
}
name = virGetUserName(uid);
if (!name)
goto cleanup;
homedir = virGetUserDirectoryByUID(uid);
if (!homedir)
goto cleanup;
if (!(conf = virConfReadFile(login_shell_path, 0)))
goto cleanup;
if ((ngroups = virGetGroupList(uid, gid, &groups)) < 0)
goto cleanup;
if (virLoginShellAllowedUser(conf, name, groups) < 0)
goto cleanup;
if (!(shargv = virLoginShellGetShellArgv(conf)))
goto cleanup;
conn = virConnectOpen("lxc:///");
if (!conn)
goto cleanup;
dom = virDomainLookupByName(conn, name);
if (!dom)
goto cleanup;
if (!virDomainIsActive(dom) && virDomainCreate(dom)) {
virErrorPtr last_error;
last_error = virGetLastError();
if (last_error->code != VIR_ERR_OPERATION_INVALID) {
virReportSystemError(last_error->code,
_("Can't create %s container: %s"),
name, last_error->message);
goto cleanup;
}
}
if ((nfdlist = virDomainLxcOpenNamespace(dom, &fdlist, 0)) < 0)
goto cleanup;
if (VIR_ALLOC(secmodel) < 0)
goto cleanup;
if (VIR_ALLOC(seclabel) < 0)
goto cleanup;
if (virNodeGetSecurityModel(conn, secmodel) < 0)
goto cleanup;
if (virDomainGetSecurityLabel(dom, seclabel) < 0)
goto cleanup;
if (virFork(&cpid) < 0)
goto cleanup;
if (cpid == 0) {
pid_t ccpid;
int openmax = sysconf(_SC_OPEN_MAX);
int fd;
/* Fork once because we don't want to affect
* virt-login-shell's namespace itself
*/
if (virSetUIDGID(0, 0, NULL, 0) < 0)
return EXIT_FAILURE;
if (virDomainLxcEnterSecurityLabel(secmodel,
seclabel,
NULL,
0) < 0)
return EXIT_FAILURE;
if (nfdlist > 0) {
if (virDomainLxcEnterNamespace(dom,
nfdlist,
fdlist,
NULL,
NULL,
0) < 0)
return EXIT_FAILURE;
}
ret = virSetUIDGID(uid, gid, groups, ngroups);
VIR_FREE(groups);
if (ret < 0)
return EXIT_FAILURE;
if (openmax < 0) {
virReportSystemError(errno, "%s",
_("sysconf(_SC_OPEN_MAX) failed"));
return EXIT_FAILURE;
}
for (fd = 3; fd < openmax; fd++) {
int tmpfd = fd;
VIR_MASS_CLOSE(tmpfd);
}
if (virFork(&ccpid) < 0)
return EXIT_FAILURE;
if (ccpid == 0) {
if (chdir(homedir) < 0) {
virReportSystemError(errno, _("Unable to chdir(%s)"), homedir);
return EXIT_FAILURE;
}
if (execv(shargv[0], (char *const*) shargv) < 0) {
virReportSystemError(errno, _("Unable to exec shell %s"),
shargv[0]);
return EXIT_FAILURE;
}
}
return virProcessWait(ccpid, &status2, true);
}
ret = virProcessWait(cpid, &status, true);
cleanup:
virConfFree(conf);
virLoginShellFini(conn, dom);
virStringFreeList(shargv);
VIR_FREE(name);
VIR_FREE(homedir);
VIR_FREE(seclabel);
VIR_FREE(secmodel);
VIR_FREE(groups);
if (ret)
virDispatchError(NULL);
return ret;
}