mirror of
https://gitlab.com/libvirt/libvirt.git
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f63cbc7365
Use contemporary style for declarations and automatic memory clearing for a helper string. Since the function can't fail any more, remove any mention of returning errno and remove error checks from all callers. Signed-off-by: Peter Krempa <pkrempa@redhat.com> Reviewed-by: Jiri Denemark <jdenemar@redhat.com>
421 lines
11 KiB
C
421 lines
11 KiB
C
/*
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* virt-login-shell-helper.c: a shell to connect to a container
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*
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* Copyright (C) 2013-2014 Red Hat, Inc.
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*
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* This 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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*
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* This 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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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library. If not, see
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* <http://www.gnu.org/licenses/>.
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*/
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#include <config.h>
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#include <getopt.h>
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#include <signal.h>
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#include <unistd.h>
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#include "internal.h"
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#include "virerror.h"
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#include "virconf.h"
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#include "virutil.h"
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#include "virfile.h"
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#include "virprocess.h"
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#include "configmake.h"
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#include "virstring.h"
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#include "viralloc.h"
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#include "vircommand.h"
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#include "virgettext.h"
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#define VIR_FROM_THIS VIR_FROM_NONE
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static const char *conf_file = SYSCONFDIR "/libvirt/virt-login-shell.conf";
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static int virLoginShellAllowedUser(virConf *conf,
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const char *name,
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gid_t *groups,
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size_t ngroups)
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{
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int ret = -1;
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size_t i;
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char *gname = NULL;
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g_auto(GStrv) users = NULL;
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char **entries;
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if (virConfGetValueStringList(conf, "allowed_users", false, &users) < 0)
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goto cleanup;
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for (entries = users; entries && *entries; entries++) {
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char *entry = *entries;
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/*
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If string begins with a % this indicates a linux group.
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Check to see if the user is in the Linux Group.
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*/
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if (entry[0] == '%') {
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entry++;
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if (!*entry)
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continue;
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for (i = 0; i < ngroups; i++) {
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if (!(gname = virGetGroupName(groups[i])))
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continue;
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if (g_pattern_match_simple(entry, gname)) {
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ret = 0;
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goto cleanup;
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}
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VIR_FREE(gname);
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}
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} else {
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if (g_pattern_match_simple(entry, name)) {
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ret = 0;
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goto cleanup;
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}
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}
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}
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virReportSystemError(EPERM,
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_("%1$s not matched against 'allowed_users' in %2$s"),
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name, conf_file);
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cleanup:
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VIR_FREE(gname);
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return ret;
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}
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static int virLoginShellGetShellArgv(virConf *conf,
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char ***shargv,
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size_t *shargvlen)
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{
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int rv;
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if ((rv = virConfGetValueStringList(conf, "shell", true, shargv)) < 0)
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return -1;
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if (rv == 0) {
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*shargv = g_new0(char *, 2);
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(*shargv)[0] = g_strdup("/bin/sh");
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*shargvlen = 1;
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} else {
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*shargvlen = g_strv_length(*shargv);
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}
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return 0;
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}
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static char *progname;
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/*
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* Print usage
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*/
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static void
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usage(void)
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{
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fprintf(stdout,
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_("\n"
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"Usage:\n"
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" %1$s [option]\n\n"
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"Options:\n"
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" -h | --help Display program help\n"
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" -V | --version Display program version\n"
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" -c CMD Run CMD via shell\n"
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"\n"
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"libvirt login shell\n"),
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progname);
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return;
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}
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/* Display version information. */
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static void
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show_version(void)
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{
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printf("%s (%s) %s\n", progname, PACKAGE_NAME, PACKAGE_VERSION);
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}
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static void
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hideErrorFunc(void *opaque G_GNUC_UNUSED,
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virErrorPtr err G_GNUC_UNUSED)
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{
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}
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int
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main(int argc, char **argv)
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{
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g_autoptr(virConf) conf = NULL;
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const char *login_shell_path = conf_file;
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pid_t cpid = -1;
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int ret = EXIT_CANCELED;
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int status;
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unsigned long long uidval;
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unsigned long long gidval;
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uid_t uid;
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gid_t gid;
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char *name = NULL;
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g_auto(GStrv) shargv = NULL;
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size_t shargvlen = 0;
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char *shcmd = NULL;
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virSecurityModelPtr secmodel = NULL;
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virSecurityLabelPtr seclabel = NULL;
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virDomainPtr dom = NULL;
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virConnectPtr conn = NULL;
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char *homedir = NULL;
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int arg;
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int longindex = -1;
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int ngroups;
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gid_t *groups = NULL;
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ssize_t nfdlist = 0;
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int *fdlist = NULL;
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int openmax;
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size_t i;
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const char *cmdstr = NULL;
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char *tmp;
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char *term = NULL;
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virErrorPtr saved_err = NULL;
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bool autoshell = false;
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struct option opt[] = {
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{ "help", no_argument, NULL, 'h' },
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{ "version", optional_argument, NULL, 'V' },
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{ NULL, 0, NULL, 0 },
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};
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if (virInitialize() < 0) {
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fprintf(stderr, _("Failed to initialize libvirt error handling"));
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return EXIT_CANCELED;
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}
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virSetErrorFunc(NULL, hideErrorFunc);
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virSetErrorLogPriorityFunc(NULL);
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progname = argv[0];
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if (virGettextInitialize() < 0)
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return ret;
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if (geteuid() != 0) {
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fprintf(stderr, _("%1$s: must be run as root\n"), argv[0]);
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return ret;
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}
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if (getuid() != 0) {
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fprintf(stderr, _("%1$s: must not be run setuid root\n"), argv[0]);
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return ret;
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}
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while ((arg = getopt_long(argc, argv, "hVc:", opt, &longindex)) != -1) {
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switch (arg) {
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case 'h':
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usage();
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exit(EXIT_SUCCESS);
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case 'V':
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show_version();
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exit(EXIT_SUCCESS);
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case 'c':
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cmdstr = optarg;
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break;
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case '?':
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default:
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usage();
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exit(EXIT_CANCELED);
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}
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}
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if (optind != (argc - 2)) {
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virReportSystemError(EINVAL, _("%1$s expects UID and GID parameters"), progname);
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goto cleanup;
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}
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if (virStrToLong_ull(argv[optind], NULL, 10, &uidval) < 0 ||
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((uid_t)uidval) != uidval) {
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virReportSystemError(EINVAL, _("%1$s cannot parse UID '%2$s'"),
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progname, argv[optind]);
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goto cleanup;
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}
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optind++;
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if (virStrToLong_ull(argv[optind], NULL, 10, &gidval) < 0 ||
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((gid_t)gidval) != gidval) {
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virReportSystemError(EINVAL, _("%1$s cannot parse GID '%2$s'"),
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progname, argv[optind]);
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goto cleanup;
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}
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uid = (uid_t)uidval;
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gid = (gid_t)gidval;
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name = virGetUserName(uid);
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if (!name)
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goto cleanup;
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homedir = virGetUserDirectoryByUID(uid);
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if (!homedir)
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goto cleanup;
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if (!(conf = virConfReadFile(login_shell_path, 0)))
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goto cleanup;
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ngroups = virGetGroupList(uid, gid, &groups);
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if (virLoginShellAllowedUser(conf, name, groups, ngroups) < 0)
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goto cleanup;
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if (virLoginShellGetShellArgv(conf, &shargv, &shargvlen) < 0)
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goto cleanup;
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if (virConfGetValueBool(conf, "auto_shell", &autoshell) < 0)
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goto cleanup;
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conn = virConnectOpen("lxc:///system");
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if (!conn)
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goto cleanup;
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dom = virDomainLookupByName(conn, name);
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if (!dom)
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goto cleanup;
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if (!virDomainIsActive(dom) && virDomainCreate(dom) < 0) {
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virErrorPtr last_error;
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last_error = virGetLastError();
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if (last_error->code != VIR_ERR_OPERATION_INVALID) {
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virReportSystemError(last_error->code,
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_("Can't create %1$s container: %2$s"),
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name, last_error->message);
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goto cleanup;
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}
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}
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openmax = sysconf(_SC_OPEN_MAX);
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if (openmax < 0) {
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virReportSystemError(errno, "%s",
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_("sysconf(_SC_OPEN_MAX) failed"));
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goto cleanup;
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}
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if ((nfdlist = virDomainLxcOpenNamespace(dom, &fdlist, 0)) < 0)
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goto cleanup;
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secmodel = g_new0(virSecurityModel, 1);
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seclabel = g_new0(virSecurityLabel, 1);
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if (virNodeGetSecurityModel(conn, secmodel) < 0)
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goto cleanup;
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if (virDomainGetSecurityLabel(dom, seclabel) < 0)
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goto cleanup;
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if (virSetUIDGID(0, 0, NULL, 0) < 0)
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goto cleanup;
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if (virDomainLxcEnterSecurityLabel(secmodel, seclabel, NULL, 0) < 0)
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goto cleanup;
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if (virDomainLxcEnterCGroup(dom, 0) < 0)
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goto cleanup;
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if (nfdlist > 0 &&
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virDomainLxcEnterNamespace(dom, nfdlist, fdlist, NULL, NULL, 0) < 0)
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goto cleanup;
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if (virSetUIDGID(uid, gid, groups, ngroups) < 0)
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goto cleanup;
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if (chdir(homedir) < 0) {
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virReportSystemError(errno, _("Unable to chdir(%1$s)"), homedir);
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goto cleanup;
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}
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if (autoshell) {
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tmp = virGetUserShell(uid);
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if (tmp) {
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g_strfreev(shargv);
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shargvlen = 1;
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shargv = g_new0(char *, shargvlen + 1);
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shargv[0] = tmp;
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shargv[1] = NULL;
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}
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}
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if (cmdstr) {
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VIR_REALLOC_N(shargv, shargvlen + 3);
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shargv[shargvlen++] = g_strdup("-c");
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shargv[shargvlen++] = g_strdup(cmdstr);
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shargv[shargvlen] = NULL;
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}
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/* We need to modify the first elementin shargv
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* so that it has the relative filename and has
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* a leading '-' to indicate it is a login shell
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*/
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shcmd = shargv[0];
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if (!g_path_is_absolute(shcmd)) {
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virReportSystemError(errno,
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_("Shell '%1$s' should have absolute path"),
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shcmd);
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goto cleanup;
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}
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tmp = strrchr(shcmd, '/');
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shargv[0] = g_strdup(tmp);
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shargv[0][0] = '-';
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/* We're duping the string because the clearenv()
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* call will shortly release the pointer we get
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* back from getenv() right here */
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term = g_strdup(getenv("TERM"));
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/* A fork is required to create new process in correct pid namespace. */
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if ((cpid = virFork()) < 0)
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goto cleanup;
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if (cpid == 0) {
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int tmpfd;
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for (i = 3; i < openmax; i++) {
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tmpfd = i;
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VIR_MASS_CLOSE(tmpfd);
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}
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clearenv();
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g_setenv("PATH", "/bin:/usr/bin", TRUE);
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g_setenv("SHELL", shcmd, TRUE);
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g_setenv("USER", name, TRUE);
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g_setenv("LOGNAME", name, TRUE);
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g_setenv("HOME", homedir, TRUE);
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if (term)
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g_setenv("TERM", term, TRUE);
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if (execv(shcmd, (char *const*) shargv) < 0) {
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virReportSystemError(errno, _("Unable to exec shell %1$s"),
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shcmd);
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virDispatchError(NULL);
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return errno == ENOENT ? EXIT_ENOENT : EXIT_CANNOT_INVOKE;
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}
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}
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/* At this point, the parent is now waiting for the child to exit,
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* but as that may take a long time, we release resources now. */
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cleanup:
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saved_err = virSaveLastError();
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if (nfdlist > 0)
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for (i = 0; i < nfdlist; i++)
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VIR_FORCE_CLOSE(fdlist[i]);
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VIR_FREE(fdlist);
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if (dom)
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virDomainFree(dom);
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if (conn)
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virConnectClose(conn);
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VIR_FREE(shcmd);
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VIR_FREE(term);
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VIR_FREE(name);
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VIR_FREE(homedir);
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VIR_FREE(seclabel);
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VIR_FREE(secmodel);
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VIR_FREE(groups);
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if (virProcessWait(cpid, &status, true) == 0)
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virProcessExitWithStatus(status);
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if (saved_err) {
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virSetError(saved_err);
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fprintf(stderr, "%s: %s\n", argv[0], virGetLastErrorMessage());
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}
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return ret;
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}
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