Adding upstream version 1.9.13p3.upstream/1.9.13p3upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 899 insertions, 0 deletions

diff --git a/src/parse_args.c b/src/parse_args.c
new file mode 100644
index 0000000..5282cc3
--- /dev/null
+++ b/src/parse_args.c
@@ -0,0 +1,899 @@
+/*
+ * SPDX-License-Identifier: ISC
+ *
+ * Copyright (c) 1993-1996, 1998-2022 Todd C. Miller <Todd.Miller@sudo.ws>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ * Sponsored in part by the Defense Advanced Research Projects
+ * Agency (DARPA) and Air Force Research Laboratory, Air Force
+ * Materiel Command, USAF, under agreement number F39502-99-1-0512.
+ */
+
+/*
+ * This is an open source non-commercial project. Dear PVS-Studio, please check it.
+ * PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com
+ */
+
+#include <config.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <ctype.h>
+#include <assert.h>
+#ifdef HAVE_GETOPT_LONG
+# include <getopt.h>
+# else
+# include "compat/getopt.h"
+#endif /* HAVE_GETOPT_LONG */
+
+#include <sudo_usage.h>
+#include "sudo.h"
+#include "sudo_lbuf.h"
+
+int tgetpass_flags;
+
+/*
+ * Local functions.
+ */
+sudo_noreturn static void help(void);
+sudo_noreturn static void usage_excl(void);
+sudo_noreturn static void usage_excl_ticket(void);
+
+/*
+ * Mapping of command line options to name/value settings.
+ * Do not reorder, indexes must match ARG_ defines in sudo.h.
+ */
+static struct sudo_settings sudo_settings[] = {
+    { "bsdauth_type" },
+    { "login_class" },
+    { "preserve_environment" },
+    { "runas_group" },
+    { "set_home" },
+    { "run_shell" },
+    { "login_shell" },
+    { "ignore_ticket" },
+    { "update_ticket" },
+    { "prompt" },
+    { "selinux_role" },
+    { "selinux_type" },
+    { "runas_user" },
+    { "progname" },
+    { "implied_shell" },
+    { "preserve_groups" },
+    { "noninteractive" },
+    { "sudoedit" },
+    { "closefrom" },
+    { "network_addrs" },
+    { "max_groups" },
+    { "plugin_dir" },
+    { "remote_host" },
+    { "timeout" },
+    { "cmnd_chroot" },
+    { "cmnd_cwd" },
+    { "askpass" },
+    { "intercept_setid" },
+    { "intercept_ptrace" },
+    { "apparmor_profile" },
+    { NULL }
+};
+
+struct environment {
+    char **envp;		/* pointer to the new environment */
+    size_t env_size;		/* size of new_environ in char **'s */
+    size_t env_len;		/* number of slots used, not counting NULL */
+};
+
+/*
+ * Default flags allowed when running a command.
+ */
+#define DEFAULT_VALID_FLAGS	(MODE_BACKGROUND|MODE_PRESERVE_ENV|MODE_RESET_HOME|MODE_LOGIN_SHELL|MODE_NONINTERACTIVE|MODE_PRESERVE_GROUPS|MODE_SHELL)
+#define EDIT_VALID_FLAGS	MODE_NONINTERACTIVE
+#define LIST_VALID_FLAGS	(MODE_NONINTERACTIVE|MODE_LONG_LIST)
+#define VALIDATE_VALID_FLAGS	MODE_NONINTERACTIVE
+
+/* Option number for the --host long option due to ambiguity of the -h flag. */
+#define OPT_HOSTNAME	256
+
+/*
+ * Available command line options, both short and long.
+ * Note that we must disable arg permutation to support setting environment
+ * variables and to better support the optional arg of the -h flag.
+ * There is a more limited set of options for sudoedit (the sudo-specific
+ * long options are listed first).
+ */
+static const char sudo_short_opts[] = "+Aa:BbC:c:D:Eeg:Hh::iKklNnPp:R:r:SsT:t:U:u:Vv";
+static const char edit_short_opts[] = "+Aa:BC:c:D:g:h::KkNnp:R:r:ST:t:u:V";
+static struct option sudo_long_opts[] = {
+    /* sudo-specific long options */
+    { "background",	no_argument,		NULL,	'b' },
+    { "preserve-env",	optional_argument,	NULL,	'E' },
+    { "edit",		no_argument,		NULL,	'e' },
+    { "set-home",	no_argument,		NULL,	'H' },
+    { "login",		no_argument,		NULL,	'i' },
+    { "remove-timestamp", no_argument,		NULL,	'K' },
+    { "list",		no_argument,		NULL,	'l' },
+    { "preserve-groups", no_argument,		NULL,	'P' },
+    { "shell",		no_argument,		NULL,	's' },
+    { "other-user",	required_argument,	NULL,	'U' },
+    { "validate",	no_argument,		NULL,	'v' },
+    /* common long options */
+    { "askpass",	no_argument,		NULL,	'A' },
+    { "auth-type",	required_argument,	NULL,	'a' },
+    { "bell",	        no_argument,		NULL,	'B' },
+    { "close-from",	required_argument,	NULL,	'C' },
+    { "login-class",	required_argument,	NULL,	'c' },
+    { "chdir",		required_argument,	NULL,	'D' },
+    { "group",		required_argument,	NULL,	'g' },
+    { "help",		no_argument,		NULL,	'h' },
+    { "host",		required_argument,	NULL,	OPT_HOSTNAME },
+    { "reset-timestamp", no_argument,		NULL,	'k' },
+    { "no-update",	no_argument,		NULL,	'N' },
+    { "non-interactive", no_argument,		NULL,	'n' },
+    { "prompt",		required_argument,	NULL,	'p' },
+    { "chroot",		required_argument,	NULL,	'R' },
+    { "role",		required_argument,	NULL,	'r' },
+    { "stdin",		no_argument,		NULL,	'S' },
+    { "command-timeout",required_argument,	NULL,	'T' },
+    { "type",		required_argument,	NULL,	't' },
+    { "user",		required_argument,	NULL,	'u' },
+    { "version",	no_argument,		NULL,	'V' },
+    { NULL,		no_argument,		NULL,	'\0' },
+};
+static struct option *edit_long_opts = &sudo_long_opts[11];
+
+/*
+ * Insert a key=value pair into the specified environment.
+ */
+static void
+env_insert(struct environment *e, char *pair)
+{
+    debug_decl(env_insert, SUDO_DEBUG_ARGS);
+
+    /* Make sure we have at least two slots free (one for NULL). */
+    if (e->env_len + 1 >= e->env_size) {
+	char **tmp;
+
+	if (e->env_size == 0)
+	    e->env_size = 16;
+	tmp = reallocarray(e->envp, e->env_size, 2 * sizeof(char *));
+	if (tmp == NULL)
+	    sudo_fatalx(U_("%s: %s"), __func__, U_("unable to allocate memory"));
+	e->envp = tmp;
+	e->env_size *= 2;
+    }
+    e->envp[e->env_len++] = pair;
+    e->envp[e->env_len] = NULL;
+
+    debug_return;
+}
+
+/*
+ * Format as var=val and insert into the specified environment.
+ */
+static void
+env_set(struct environment *e, char *var, char *val)
+{
+    char *pair;
+    debug_decl(env_set, SUDO_DEBUG_ARGS);
+
+    pair = sudo_new_key_val(var, val);
+    if (pair == NULL) {
+	sudo_fatalx(U_("%s: %s"),
+	    __func__, U_("unable to allocate memory"));
+    }
+    env_insert(e, pair);
+
+    debug_return;
+}
+
+/*
+ * Parse a comma-separated list of env vars and add to the
+ * specified environment.
+ */
+static void
+parse_env_list(struct environment *e, char *list)
+{
+    char *cp, *last, *val;
+    debug_decl(parse_env_list, SUDO_DEBUG_ARGS);
+
+    for ((cp = strtok_r(list, ",", &last)); cp != NULL;
+	(cp = strtok_r(NULL, ",", &last))) {
+	if (strchr(cp, '=') != NULL) {
+	    sudo_warnx(U_("invalid environment variable name: %s"), cp);
+	    usage();
+	}
+	if ((val = getenv(cp)) != NULL)
+	    env_set(e, cp, val);
+    }
+    debug_return;
+}
+
+/*
+ * Command line argument parsing.
+ * Sets nargc and nargv which corresponds to the argc/argv we'll use
+ * for the command to be run (if we are running one).
+ */
+int
+parse_args(int argc, char **argv, int *old_optind, int *nargc, char ***nargv,
+    struct sudo_settings **settingsp, char ***env_addp)
+{
+    const char *progname, *short_opts = sudo_short_opts;
+    struct option *long_opts = sudo_long_opts;
+    struct environment extra_env;
+    int mode = 0;		/* what mode is sudo to be run in? */
+    int flags = 0;		/* mode flags */
+    int valid_flags = DEFAULT_VALID_FLAGS;
+    int ch, i;
+    char *cp;
+    debug_decl(parse_args, SUDO_DEBUG_ARGS);
+
+    /* Is someone trying something funny? */
+    if (argc <= 0)
+	usage();
+
+    /* The plugin API includes the program name (either sudo or sudoedit). */
+    progname = getprogname();
+    sudo_settings[ARG_PROGNAME].value = progname;
+
+    /* First, check to see if we were invoked as "sudoedit". */
+    if (strcmp(progname, "sudoedit") == 0) {
+	mode = MODE_EDIT;
+	sudo_settings[ARG_SUDOEDIT].value = "true";
+	valid_flags = EDIT_VALID_FLAGS;
+	short_opts = edit_short_opts;
+	long_opts = edit_long_opts;
+    }
+
+    /* Load local IP addresses and masks. */
+    if (get_net_ifs(&cp) > 0)
+	sudo_settings[ARG_NET_ADDRS].value = cp;
+
+    /* Set max_groups from sudo.conf. */
+    i = sudo_conf_max_groups();
+    if (i != -1) {
+	if (asprintf(&cp, "%d", i) == -1)
+	    sudo_fatalx(U_("%s: %s"), __func__, U_("unable to allocate memory"));
+	sudo_settings[ARG_MAX_GROUPS].value = cp;
+    }
+
+    /* Returns true if the last option string was "-h" */
+#define got_host_flag	(optind > 1 && argv[optind - 1][0] == '-' && \
+	    argv[optind - 1][1] == 'h' && argv[optind - 1][2] == '\0')
+
+    /* Returns true if the last option string was "--" */
+#define got_end_of_args	(optind > 1 && argv[optind - 1][0] == '-' && \
+	    argv[optind - 1][1] == '-' && argv[optind - 1][2] == '\0')
+
+    /* Returns true if next option is an environment variable */
+#define is_envar (optind < argc && argv[optind][0] != '/' && \
+	    argv[optind][0] != '=' && strchr(argv[optind], '=') != NULL)
+
+    /* Space for environment variables is lazy allocated. */
+    memset(&extra_env, 0, sizeof(extra_env));
+
+    for (;;) {
+	/*
+	 * Some trickiness is required to allow environment variables
+	 * to be interspersed with command line options.
+	 */
+	if ((ch = getopt_long(argc, argv, short_opts, long_opts, NULL)) != -1) {
+	    switch (ch) {
+		case 'A':
+		    SET(tgetpass_flags, TGP_ASKPASS);
+		    sudo_settings[ARG_ASKPASS].value = "true";
+		    break;
+#ifdef HAVE_BSD_AUTH_H
+		case 'a':
+		    assert(optarg != NULL);
+		    if (*optarg == '\0')
+			usage();
+		    if (sudo_settings[ARG_BSDAUTH_TYPE].value != NULL)
+			usage();
+		    sudo_settings[ARG_BSDAUTH_TYPE].value = optarg;
+		    break;
+#endif
+		case 'b':
+		    SET(flags, MODE_BACKGROUND);
+		    break;
+		case 'B':
+		    SET(tgetpass_flags, TGP_BELL);
+		    break;
+		case 'C':
+		    assert(optarg != NULL);
+		    if (sudo_strtonum(optarg, 3, INT_MAX, NULL) == 0) {
+			sudo_warnx("%s",
+			    U_("the argument to -C must be a number greater than or equal to 3"));
+			usage();
+		    }
+		    if (sudo_settings[ARG_CLOSEFROM].value != NULL)
+			usage();
+		    sudo_settings[ARG_CLOSEFROM].value = optarg;
+		    break;
+#ifdef HAVE_LOGIN_CAP_H
+		case 'c':
+		    assert(optarg != NULL);
+		    if (*optarg == '\0')
+			usage();
+		    if (sudo_settings[ARG_LOGIN_CLASS].value != NULL)
+			usage();
+		    sudo_settings[ARG_LOGIN_CLASS].value = optarg;
+		    break;
+#endif
+		case 'D':
+		    assert(optarg != NULL);
+		    if (*optarg == '\0')
+			usage();
+		    if (sudo_settings[ARG_CWD].value != NULL)
+			usage();
+		    sudo_settings[ARG_CWD].value = optarg;
+		    break;
+		case 'E':
+		    /*
+		     * Optional argument is a comma-separated list of
+		     * environment variables to preserve.
+		     * If not present, preserve everything.
+		     */
+		    if (optarg == NULL) {
+			sudo_settings[ARG_PRESERVE_ENVIRONMENT].value = "true";
+			SET(flags, MODE_PRESERVE_ENV);
+		    } else {
+			parse_env_list(&extra_env, optarg);
+		    }
+		    break;
+		case 'e':
+		    if (mode && mode != MODE_EDIT)
+			usage_excl();
+		    mode = MODE_EDIT;
+		    sudo_settings[ARG_SUDOEDIT].value = "true";
+		    valid_flags = EDIT_VALID_FLAGS;
+		    break;
+		case 'g':
+		    assert(optarg != NULL);
+		    if (*optarg == '\0')
+			usage();
+		    if (sudo_settings[ARG_RUNAS_GROUP].value != NULL)
+			usage();
+		    sudo_settings[ARG_RUNAS_GROUP].value = optarg;
+		    break;
+		case 'H':
+		    sudo_settings[ARG_SET_HOME].value = "true";
+		    SET(flags, MODE_RESET_HOME);
+		    break;
+		case 'h':
+		    if (optarg == NULL) {
+			/*
+			 * Optional args support -hhostname, not -h hostname.
+			 * If we see a non-option after the -h flag, treat as
+			 * remote host and bump optind to skip over it.
+			 */
+			if (got_host_flag && argv[optind] != NULL &&
+			    argv[optind][0] != '-' && !is_envar) {
+			    if (sudo_settings[ARG_REMOTE_HOST].value != NULL)
+				usage();
+			    sudo_settings[ARG_REMOTE_HOST].value = argv[optind++];
+			    continue;
+			}
+			if (mode && mode != MODE_HELP) {
+			    if (strcmp(progname, "sudoedit") != 0)
+				usage_excl();
+			}
+			mode = MODE_HELP;
+			valid_flags = 0;
+			break;
+		    }
+		    FALLTHROUGH;
+		case OPT_HOSTNAME:
+		    assert(optarg != NULL);
+		    if (*optarg == '\0')
+			usage();
+		    if (sudo_settings[ARG_REMOTE_HOST].value != NULL)
+			usage();
+		    sudo_settings[ARG_REMOTE_HOST].value = optarg;
+		    break;
+		case 'i':
+		    sudo_settings[ARG_LOGIN_SHELL].value = "true";
+		    SET(flags, MODE_LOGIN_SHELL);
+		    break;
+		case 'K':
+		    if (mode && mode != MODE_KILL)
+			usage_excl();
+		    mode = MODE_KILL;
+		    valid_flags = 0;
+		    FALLTHROUGH;
+		case 'k':
+		    if (sudo_settings[ARG_UPDATE_TICKET].value != NULL)
+			usage_excl_ticket();
+		    sudo_settings[ARG_IGNORE_TICKET].value = "true";
+		    break;
+		case 'l':
+		    if (mode) {
+			if (mode == MODE_LIST)
+			    SET(flags, MODE_LONG_LIST);
+			else
+			    usage_excl();
+		    }
+		    mode = MODE_LIST;
+		    valid_flags = LIST_VALID_FLAGS;
+		    break;
+		case 'N':
+		    if (sudo_settings[ARG_IGNORE_TICKET].value != NULL)
+			usage_excl_ticket();
+		    sudo_settings[ARG_UPDATE_TICKET].value = "false";
+		    break;
+		case 'n':
+		    SET(flags, MODE_NONINTERACTIVE);
+		    sudo_settings[ARG_NONINTERACTIVE].value = "true";
+		    break;
+		case 'P':
+		    sudo_settings[ARG_PRESERVE_GROUPS].value = "true";
+		    SET(flags, MODE_PRESERVE_GROUPS);
+		    break;
+		case 'p':
+		    /* An empty prompt is allowed. */
+		    assert(optarg != NULL);
+		    if (sudo_settings[ARG_PROMPT].value != NULL)
+			usage();
+		    sudo_settings[ARG_PROMPT].value = optarg;
+		    break;
+		case 'R':
+		    assert(optarg != NULL);
+		    if (*optarg == '\0')
+			usage();
+		    if (sudo_settings[ARG_CHROOT].value != NULL)
+			usage();
+		    sudo_settings[ARG_CHROOT].value = optarg;
+		    break;
+#ifdef HAVE_SELINUX
+		case 'r':
+		    assert(optarg != NULL);
+		    if (*optarg == '\0')
+			usage();
+		    if (sudo_settings[ARG_SELINUX_ROLE].value != NULL)
+			usage();
+		    sudo_settings[ARG_SELINUX_ROLE].value = optarg;
+		    break;
+		case 't':
+		    assert(optarg != NULL);
+		    if (*optarg == '\0')
+			usage();
+		    if (sudo_settings[ARG_SELINUX_TYPE].value != NULL)
+			usage();
+		    sudo_settings[ARG_SELINUX_TYPE].value = optarg;
+		    break;
+#endif
+		case 'T':
+		    /* Plugin determines whether empty timeout is allowed. */
+		    assert(optarg != NULL);
+		    if (sudo_settings[ARG_TIMEOUT].value != NULL)
+			usage();
+		    sudo_settings[ARG_TIMEOUT].value = optarg;
+		    break;
+		case 'S':
+		    SET(tgetpass_flags, TGP_STDIN);
+		    break;
+		case 's':
+		    sudo_settings[ARG_USER_SHELL].value = "true";
+		    SET(flags, MODE_SHELL);
+		    break;
+		case 'U':
+		    assert(optarg != NULL);
+		    if (list_user != NULL || *optarg == '\0')
+			usage();
+		    list_user = optarg;
+		    break;
+		case 'u':
+		    assert(optarg != NULL);
+		    if (*optarg == '\0')
+			usage();
+		    if (sudo_settings[ARG_RUNAS_USER].value != NULL)
+			usage();
+		    sudo_settings[ARG_RUNAS_USER].value = optarg;
+		    break;
+		case 'v':
+		    if (mode && mode != MODE_VALIDATE)
+			usage_excl();
+		    mode = MODE_VALIDATE;
+		    valid_flags = VALIDATE_VALID_FLAGS;
+		    break;
+		case 'V':
+		    if (mode && mode != MODE_VERSION) {
+			if (strcmp(progname, "sudoedit") != 0)
+			    usage_excl();
+		    }
+		    mode = MODE_VERSION;
+		    valid_flags = 0;
+		    break;
+		default:
+		    usage();
+	    }
+	} else if (!got_end_of_args && is_envar) {
+	    /* Insert key=value pair, crank optind and resume getopt. */
+	    env_insert(&extra_env, argv[optind]);
+	    optind++;
+	} else {
+	    /* Not an option or an environment variable -- we're done. */
+	    break;
+	}
+    }
+
+    argc -= optind;
+    argv += optind;
+    *old_optind = optind;
+
+    if (!mode) {
+	/* Defer -k mode setting until we know whether it is a flag or not */
+	if (sudo_settings[ARG_IGNORE_TICKET].value != NULL) {
+	    if (argc == 0 && !ISSET(flags, MODE_SHELL|MODE_LOGIN_SHELL)) {
+		mode = MODE_INVALIDATE;	/* -k by itself */
+		sudo_settings[ARG_IGNORE_TICKET].value = NULL;
+		valid_flags = 0;
+	    }
+	}
+	if (!mode)
+	    mode = MODE_RUN;		/* running a command */
+    }
+
+    if (argc > 0 && mode == MODE_LIST)
+	mode = MODE_CHECK;
+
+    if (ISSET(flags, MODE_LOGIN_SHELL)) {
+	if (ISSET(flags, MODE_SHELL)) {
+	    sudo_warnx("%s",
+		U_("you may not specify both the -i and -s options"));
+	    usage();
+	}
+	if (ISSET(flags, MODE_PRESERVE_ENV)) {
+	    sudo_warnx("%s",
+		U_("you may not specify both the -i and -E options"));
+	    usage();
+	}
+	SET(flags, MODE_SHELL);
+    }
+    if ((flags & valid_flags) != flags)
+	usage();
+    if (mode == MODE_EDIT &&
+       (ISSET(flags, MODE_PRESERVE_ENV) || extra_env.env_len != 0)) {
+	if (ISSET(mode, MODE_PRESERVE_ENV))
+	    sudo_warnx("%s", U_("the -E option is not valid in edit mode"));
+	if (extra_env.env_len != 0)
+	    sudo_warnx("%s",
+		U_("you may not specify environment variables in edit mode"));
+	usage();
+    }
+    if ((sudo_settings[ARG_RUNAS_USER].value != NULL ||
+	 sudo_settings[ARG_RUNAS_GROUP].value != NULL) &&
+	!ISSET(mode, MODE_EDIT | MODE_RUN | MODE_CHECK | MODE_VALIDATE)) {
+	usage();
+    }
+    if (list_user != NULL && mode != MODE_LIST && mode != MODE_CHECK) {
+	sudo_warnx("%s",
+	    U_("the -U option may only be used with the -l option"));
+	usage();
+    }
+    if (ISSET(tgetpass_flags, TGP_STDIN) && ISSET(tgetpass_flags, TGP_ASKPASS)) {
+	sudo_warnx("%s", U_("the -A and -S options may not be used together"));
+	usage();
+    }
+    if ((argc == 0 && mode == MODE_EDIT) ||
+	(argc > 0 && !ISSET(mode, MODE_RUN | MODE_EDIT | MODE_CHECK)))
+	usage();
+    if (argc == 0 && mode == MODE_RUN && !ISSET(flags, MODE_SHELL)) {
+	SET(flags, (MODE_IMPLIED_SHELL | MODE_SHELL));
+	sudo_settings[ARG_IMPLIED_SHELL].value = "true";
+    }
+#ifdef ENABLE_SUDO_PLUGIN_API
+    sudo_settings[ARG_PLUGIN_DIR].value = sudo_conf_plugin_dir_path();
+#endif
+    if (exec_ptrace_intercept_supported())
+	sudo_settings[ARG_INTERCEPT_SETID].value = "true";
+    if (exec_ptrace_subcmds_supported())
+	sudo_settings[ARG_INTERCEPT_PTRACE].value = "true";
+
+    if (mode == MODE_HELP)
+	help();
+
+    /*
+     * For shell mode we need to rewrite argv
+     * TODO: move this to the policy plugin and make escaping configurable
+     */
+    if (ISSET(flags, MODE_SHELL|MODE_LOGIN_SHELL) && ISSET(mode, MODE_RUN)) {
+	char **av, *cmnd = NULL;
+	int ac = 1;
+
+	if (argc != 0) {
+	    /* shell -c "command" */
+	    char *src, *dst;
+	    size_t size = 0;
+
+	    for (av = argv; *av != NULL; av++)
+		size += strlen(*av) + 1;
+	    if (size == 0 || (cmnd = reallocarray(NULL, size, 2)) == NULL)
+		sudo_fatalx(U_("%s: %s"), __func__, U_("unable to allocate memory"));
+	    if (!gc_add(GC_PTR, cmnd))
+		exit(EXIT_FAILURE);
+
+	    for (dst = cmnd, av = argv; *av != NULL; av++) {
+		for (src = *av; *src != '\0'; src++) {
+		    /* quote potential meta characters */
+		    if (!isalnum((unsigned char)*src) && *src != '_' && *src != '-' && *src != '$')
+			*dst++ = '\\';
+		    *dst++ = *src;
+		}
+		*dst++ = ' ';
+	    }
+	    if (cmnd != dst)
+		dst--;  /* replace last space with a NUL */
+	    *dst = '\0';
+
+	    ac += 2; /* -c cmnd */
+	}
+
+	av = reallocarray(NULL, ac + 1, sizeof(char *));
+	if (av == NULL)
+	    sudo_fatalx(U_("%s: %s"), __func__, U_("unable to allocate memory"));
+	if (!gc_add(GC_PTR, av))
+	    exit(EXIT_FAILURE);
+
+	av[0] = (char *)user_details.shell; /* plugin may override shell */
+	if (cmnd != NULL) {
+	    av[1] = (char *)"-c";
+	    av[2] = cmnd;
+	}
+	av[ac] = NULL;
+
+	argv = av;
+	argc = ac;
+    }
+
+    /*
+     * For sudoedit we need to rewrite argv
+     */
+    if (mode == MODE_EDIT) {
+#if defined(HAVE_SETRESUID) || defined(HAVE_SETREUID) || defined(HAVE_SETEUID)
+	char **av;
+	int ac;
+
+	av = reallocarray(NULL, argc + 2, sizeof(char *));
+	if (av == NULL)
+	    sudo_fatalx(U_("%s: %s"), __func__, U_("unable to allocate memory"));
+	if (!gc_add(GC_PTR, av))
+	    exit(EXIT_FAILURE);
+
+	/* Must have the command in argv[0]. */
+	av[0] = (char *)"sudoedit";
+	for (ac = 0; argv[ac] != NULL; ac++) {
+	    av[ac + 1] = argv[ac];
+	}
+	av[++ac] = NULL;
+
+	argv = av;
+	argc = ac;
+#else
+	sudo_fatalx("%s", U_("sudoedit is not supported on this platform"));
+#endif
+    }
+
+    *settingsp = sudo_settings;
+    *env_addp = extra_env.envp;
+    *nargc = argc;
+    *nargv = argv;
+    debug_return_int(mode | flags);
+}
+
+static int
+usage_err(const char *buf)
+{
+    return fputs(buf, stderr);
+}
+
+static int
+usage_out(const char *buf)
+{
+    return fputs(buf, stdout);
+}
+
+/*
+ * Display usage message.
+ * The actual usage strings are in sudo_usage.h for configure substitution.
+ */
+static void
+display_usage(int (*output)(const char *))
+{
+    struct sudo_lbuf lbuf;
+    const char *uvec[6];
+    int i, ulen;
+
+    /*
+     * Use usage vectors appropriate to the progname.
+     */
+    if (strcmp(getprogname(), "sudoedit") == 0) {
+	uvec[0] = SUDO_USAGE0;
+	uvec[1] = &SUDO_USAGE5[3];	/* skip the leading "-e " */
+	uvec[2] = NULL;
+    } else {
+	uvec[0] = SUDO_USAGE1;
+	uvec[1] = SUDO_USAGE2;
+	uvec[2] = SUDO_USAGE3;
+	uvec[3] = SUDO_USAGE4;
+	uvec[4] = SUDO_USAGE5;
+	uvec[5] = NULL;
+    }
+
+    /*
+     * Print usage and wrap lines as needed, depending on the
+     * tty width.
+     */
+    ulen = (int)strlen(getprogname()) + 8;
+    sudo_lbuf_init(&lbuf, output, ulen, NULL,
+	user_details.ts_cols);
+    for (i = 0; uvec[i] != NULL; i++) {
+	sudo_lbuf_append(&lbuf, "usage: %s%s", getprogname(), uvec[i]);
+	sudo_lbuf_print(&lbuf);
+    }
+    sudo_lbuf_destroy(&lbuf);
+}
+
+/*
+ * Display usage message and exit.
+ */
+void
+usage(void)
+{
+    display_usage(usage_err);
+    exit(EXIT_FAILURE);
+}
+
+/*
+ * Tell which options are mutually exclusive and exit.
+ */
+static void
+usage_excl(void)
+{
+    debug_decl(usage_excl, SUDO_DEBUG_ARGS);
+
+    sudo_warnx("%s",
+	U_("Only one of the -e, -h, -i, -K, -l, -s, -v or -V options may be specified"));
+    usage();
+}
+
+/*
+ * Tell which options are mutually exclusive and exit.
+ */
+static void
+usage_excl_ticket(void)
+{
+    debug_decl(usage_excl_ticket, SUDO_DEBUG_ARGS);
+
+    sudo_warnx("%s",
+	U_("Only one of the -K, -k or -N options may be specified"));
+    usage();
+}
+
+static void
+help(void)
+{
+    struct sudo_lbuf lbuf;
+    const int indent = 32;
+    const char *pname = getprogname();
+    bool sudoedit = false;
+    debug_decl(help, SUDO_DEBUG_ARGS);
+
+    sudo_lbuf_init(&lbuf, usage_out, indent, NULL, user_details.ts_cols);
+    if (strcmp(pname, "sudoedit") == 0) {
+	sudoedit = true;
+	sudo_lbuf_append(&lbuf, _("%s - edit files as another user\n\n"), pname);
+    } else {
+	sudo_lbuf_append(&lbuf, _("%s - execute a command as another user\n\n"), pname);
+    }
+    sudo_lbuf_print(&lbuf);
+
+    display_usage(usage_out);
+
+    sudo_lbuf_append(&lbuf, "%s", _("\nOptions:\n"));
+    sudo_lbuf_append(&lbuf, "  -A, --askpass                 %s\n",
+	_("use a helper program for password prompting"));
+#ifdef HAVE_BSD_AUTH_H
+    sudo_lbuf_append(&lbuf, "  -a, --auth-type=type          %s\n",
+	_("use specified BSD authentication type"));
+#endif
+    if (!sudoedit) {
+	sudo_lbuf_append(&lbuf, "  -b, --background              %s\n",
+	    _("run command in the background"));
+    }
+    sudo_lbuf_append(&lbuf, "  -B, --bell                    %s\n",
+	_("ring bell when prompting"));
+    sudo_lbuf_append(&lbuf, "  -C, --close-from=num          %s\n",
+	_("close all file descriptors >= num"));
+#ifdef HAVE_LOGIN_CAP_H
+    sudo_lbuf_append(&lbuf, "  -c, --login-class=class       %s\n",
+	_("run command with the specified BSD login class"));
+#endif
+    sudo_lbuf_append(&lbuf, "  -D, --chdir=directory         %s\n",
+	_("change the working directory before running command"));
+    if (!sudoedit) {
+	sudo_lbuf_append(&lbuf, "  -E, --preserve-env            %s\n",
+	    _("preserve user environment when running command"));
+	sudo_lbuf_append(&lbuf, "      --preserve-env=list       %s\n",
+	    _("preserve specific environment variables"));
+	sudo_lbuf_append(&lbuf, "  -e, --edit                    %s\n",
+	    _("edit files instead of running a command"));
+    }
+    sudo_lbuf_append(&lbuf, "  -g, --group=group             %s\n",
+	_("run command as the specified group name or ID"));
+    if (!sudoedit) {
+	sudo_lbuf_append(&lbuf, "  -H, --set-home                %s\n",
+	    _("set HOME variable to target user's home dir"));
+    }
+    sudo_lbuf_append(&lbuf, "  -h, --help                    %s\n",
+	_("display help message and exit"));
+    sudo_lbuf_append(&lbuf, "  -h, --host=host               %s\n",
+	_("run command on host (if supported by plugin)"));
+    if (!sudoedit) {
+	sudo_lbuf_append(&lbuf, "  -i, --login                   %s\n",
+	    _("run login shell as the target user; a command may also be specified"));
+	sudo_lbuf_append(&lbuf, "  -K, --remove-timestamp        %s\n",
+	    _("remove timestamp file completely"));
+    }
+    sudo_lbuf_append(&lbuf, "  -k, --reset-timestamp         %s\n",
+	_("invalidate timestamp file"));
+    if (!sudoedit) {
+	sudo_lbuf_append(&lbuf, "  -l, --list                    %s\n",
+	    _("list user's privileges or check a specific command; use twice for longer format"));
+    }
+    sudo_lbuf_append(&lbuf, "  -n, --non-interactive         %s\n",
+	_("non-interactive mode, no prompts are used"));
+    if (!sudoedit) {
+	sudo_lbuf_append(&lbuf, "  -P, --preserve-groups         %s\n",
+	    _("preserve group vector instead of setting to target's"));
+    }
+    sudo_lbuf_append(&lbuf, "  -p, --prompt=prompt           %s\n",
+	_("use the specified password prompt"));
+    sudo_lbuf_append(&lbuf, "  -R, --chroot=directory        %s\n",
+	_("change the root directory before running command"));
+#ifdef HAVE_SELINUX
+    sudo_lbuf_append(&lbuf, "  -r, --role=role               %s\n",
+	_("create SELinux security context with specified role"));
+#endif
+    sudo_lbuf_append(&lbuf, "  -S, --stdin                   %s\n",
+	_("read password from standard input"));
+    if (!sudoedit) {
+	sudo_lbuf_append(&lbuf, "  -s, --shell                   %s\n",
+	    _("run shell as the target user; a command may also be specified"));
+    }
+#ifdef HAVE_SELINUX
+    sudo_lbuf_append(&lbuf, "  -t, --type=type               %s\n",
+	_("create SELinux security context with specified type"));
+#endif
+    sudo_lbuf_append(&lbuf, "  -T, --command-timeout=timeout %s\n",
+	_("terminate command after the specified time limit"));
+    if (!sudoedit) {
+	sudo_lbuf_append(&lbuf, "  -U, --other-user=user         %s\n",
+	    _("in list mode, display privileges for user"));
+    }
+    sudo_lbuf_append(&lbuf, "  -u, --user=user               %s\n",
+	_("run command (or edit file) as specified user name or ID"));
+    sudo_lbuf_append(&lbuf, "  -V, --version                 %s\n",
+	_("display version information and exit"));
+    if (!sudoedit) {
+	sudo_lbuf_append(&lbuf, "  -v, --validate                %s\n",
+	    _("update user's timestamp without running a command"));
+    }
+    sudo_lbuf_append(&lbuf, "  --                            %s\n",
+	_("stop processing command line arguments"));
+    sudo_lbuf_print(&lbuf);
+    sudo_lbuf_destroy(&lbuf);
+    sudo_debug_exit_int(__func__, __FILE__, __LINE__, sudo_debug_subsys, 0);
+    exit(EXIT_SUCCESS);
+}