Return to cmd-string.c CVS log

Up to [local] / src / usr.bin / tmux

Rewrite a confusing loop when freeing the arg array on exit and move the check
for argv being NULL, prompted by parfait via deraadt.

Also fix some definite brokenness when assigning multiple environment variables
in arguments (such as "X=1 Y=2").

/* $OpenBSD: cmd-string.c,v 1.8 2009/11/11 18:56:07 nicm Exp $ */

/*
 * Copyright (c) 2008 Nicholas Marriott <nicm@users.sourceforge.net>
 *
 * 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 MIND, 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.
 */

#include <sys/types.h>

#include <errno.h>
#include <pwd.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>

#include "tmux.h"

/*
 * Parse a command from a string.
 */

int	cmd_string_getc(const char *, size_t *);
void	cmd_string_ungetc(const char *, size_t *);
char   *cmd_string_string(const char *, size_t *, char, int);
char   *cmd_string_variable(const char *, size_t *);
char   *cmd_string_expand_tilde(const char *, size_t *);

int
cmd_string_getc(const char *s, size_t *p)
{
	if (s[*p] == '\0')
		return (EOF);
	return (s[(*p)++]);
}

void
cmd_string_ungetc(unused const char *s, size_t *p)
{
	(*p)--;
}

/*
 * Parse command string. Returns -1 on error. If returning -1, cause is error
 * string, or NULL for empty command.
 */
int
cmd_string_parse(const char *s, struct cmd_list **cmdlist, char **cause)
{
	size_t		p;
	int		ch, i, argc, rval, have_arg;
	char	      **argv, *buf, *t;
	const char     *whitespace, *equals;
	size_t		len;

	argv = NULL;
	argc = 0;

	buf = NULL;
	len = 0;

	have_arg = 0;

	*cause = NULL;

	*cmdlist = NULL;
	rval = -1;

	p = 0;
	for (;;) {
		ch = cmd_string_getc(s, &p);
		switch (ch) {
		case '\'':
			if ((t = cmd_string_string(s, &p, '\'', 0)) == NULL)
				goto error;
			buf = xrealloc(buf, 1, len + strlen(t) + 1);
			strlcpy(buf + len, t, strlen(t) + 1);
			len += strlen(t);
			xfree(t);

			have_arg = 1;
			break;
		case '"':
			if ((t = cmd_string_string(s, &p, '"', 1)) == NULL)
				goto error;
			buf = xrealloc(buf, 1, len + strlen(t) + 1);
			strlcpy(buf + len, t, strlen(t) + 1);
			len += strlen(t);
			xfree(t);

			have_arg = 1;
			break;
		case '$':
			if ((t = cmd_string_variable(s, &p)) == NULL)
				goto error;
			buf = xrealloc(buf, 1, len + strlen(t) + 1);
			strlcpy(buf + len, t, strlen(t) + 1);
			len += strlen(t);
			xfree(t);

			have_arg = 1;
			break;
		case '#':
			/* Comment: discard rest of line. */
			while ((ch = cmd_string_getc(s, &p)) != EOF)
				;
			/* FALLTHROUGH */
		case EOF:
		case ' ':
		case '\t':
 			if (have_arg) {
				buf = xrealloc(buf, 1, len + 1);
				buf[len] = '\0';

				argv = xrealloc(argv, argc + 1, sizeof *argv);
				argv[argc++] = buf;

				buf = NULL;
				len = 0;

				have_arg = 0;
			}

			if (ch != EOF)
				break;

			while (argc != 0) {
				equals = strchr(argv[0], '=');
				whitespace = argv[0] + strcspn(argv[0], " \t");
				if (equals == NULL || equals > whitespace)
					break;
				environ_put(&global_environ, argv[0]);
				argc--;
				memmove(argv, argv + 1, argc * (sizeof *argv));
			}
			if (argc == 0)
				goto out;

			*cmdlist = cmd_list_parse(argc, argv, cause);
			if (*cmdlist == NULL)
				goto out;

			do
				xfree(argv[argc - 1]);
			while (--argc > 0);

			rval = 0;
			goto out;
		case '~':
			if (have_arg == 0) {
				if ((t = cmd_string_expand_tilde(s, &p)) == NULL)
					goto error;
				buf = xrealloc(buf, 1, len + strlen(t) + 1);
				strlcpy(buf + len, t, strlen(t) + 1);
				len += strlen(t);
				xfree(t);
				break;
			}
			/* FALLTHROUGH */
		default:
			if (len >= SIZE_MAX - 2)
				goto error;

			buf = xrealloc(buf, 1, len + 1);
			buf[len++] = ch;

			have_arg = 1;
			break;
		}
	}

error:
	xasprintf(cause, "invalid or unknown command: %s", s);

out:
	if (buf != NULL)
		xfree(buf);

	if (argv != NULL) {
		for (i = 0; i < argc; i++)
			xfree(argv[argc]);
		xfree(argv);
	}

	return (rval);
}

char *
cmd_string_string(const char *s, size_t *p, char endch, int esc)
{
	int	ch;
	char   *buf, *t;
	size_t	len;

	buf = NULL;
	len = 0;

	while ((ch = cmd_string_getc(s, p)) != endch) {
		switch (ch) {
		case EOF:
			goto error;
		case '\\':
			if (!esc)
				break;
			switch (ch = cmd_string_getc(s, p)) {
			case EOF:
				goto error;
			case 'e':
				ch = '\033';
				break;
			case 'r':
				ch = '\r';
				break;
			case 'n':
				ch = '\n';
				break;
			case 't':
				ch = '\t';
				break;
			}
			break;
		case '$':
			if (!esc)
				break;
			if ((t = cmd_string_variable(s, p)) == NULL)
				goto error;
			buf = xrealloc(buf, 1, len + strlen(t) + 1);
			strlcpy(buf + len, t, strlen(t) + 1);
			len += strlen(t);
			xfree(t);
			continue;
		}

		if (len >= SIZE_MAX - 2)
			goto error;
		buf = xrealloc(buf, 1, len + 1);
		buf[len++] = ch;
	}

	buf = xrealloc(buf, 1, len + 1);
	buf[len] = '\0';
	return (buf);

error:
	if (buf != NULL)
		xfree(buf);
	return (NULL);
}

char *
cmd_string_variable(const char *s, size_t *p)
{
	int	ch, fch;
	char   *buf, *t;
	size_t	len;

#define cmd_string_first(ch) ((ch) == '_' || \
	((ch) >= 'a' && (ch) <= 'z') || ((ch) >= 'A' && (ch) <= 'Z'))
#define cmd_string_other(ch) ((ch) == '_' || \
	((ch) >= 'a' && (ch) <= 'z') || ((ch) >= 'A' && (ch) <= 'Z') || \
	((ch) >= '0' && (ch) <= '9'))

	buf = NULL;
	len = 0;

	fch = EOF;
	switch (ch = cmd_string_getc(s, p)) {
	case EOF:
		goto error;
	case '{':
		fch = '{';

		ch = cmd_string_getc(s, p);
		if (!cmd_string_first(ch))
			goto error;
		/* FALLTHROUGH */
	default:
		if (!cmd_string_first(ch)) {
			xasprintf(&t, "$%c", ch);
			return (t);
		}

		buf = xrealloc(buf, 1, len + 1);
		buf[len++] = ch;

		for (;;) {
			ch = cmd_string_getc(s, p);
			if (ch == EOF || !cmd_string_other(ch))
				break;
			else {
				if (len >= SIZE_MAX - 3)
					goto error;
				buf = xrealloc(buf, 1, len + 1);
				buf[len++] = ch;
			}
		}
	}

	if (fch == '{' && ch != '}')
		goto error;
	if (ch != EOF && fch != '{')
		cmd_string_ungetc(s, p); /* ch */

	buf = xrealloc(buf, 1, len + 1);
	buf[len] = '\0';

	if ((t = getenv(buf)) == NULL) {
		xfree(buf);
		return (xstrdup(""));
	}
	xfree(buf);
	return (xstrdup(t));

error:
	if (buf != NULL)
		xfree(buf);
	return (NULL);
}

char *
cmd_string_expand_tilde(const char *s, size_t *p)
{
	struct passwd	*pw;
	char		*home, *path, *username;

	home = NULL;
	if (cmd_string_getc(s, p) == '/') {
		if ((home = getenv("HOME")) == NULL) {
			if ((pw = getpwuid(getuid())) != NULL)
				home = pw->pw_dir;
		}
	} else {
		cmd_string_ungetc(s, p);
		if ((username = cmd_string_string(s, p, '/', 0)) == NULL)
			return (NULL);
		if ((pw = getpwnam(username)) != NULL)
			home = pw->pw_dir;
		if (username != NULL)
			xfree(username);
	}
	if (home == NULL)
		return (NULL);

	xasprintf(&path, "%s/", home);
	return (path);
}