wordexp.c

Axis 221 camera embedded programing interface

/* vi: set sw=4 ts=4: */
/* POSIX.2 wordexp implementation.
   Copyright (C) 1997, 1998, 1999 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Tim Waugh <[e-mail]>.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Library General Public License as
   published by the Free Software Foundation; either version 2 of the
   License, or (at your option) any later version.

   The GNU C 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
   Library General Public License for more details.

   You should have received a copy of the GNU Library General Public
   License along with the GNU C Library; see the file COPYING.LIB.  If not,
   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
   Boston, MA 02111-1307, USA.  */

#define _GNU_SOURCE
#include <sys/cdefs.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <fcntl.h>
#include <paths.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <pwd.h>
#include <errno.h>
#include <assert.h>
#include <fnmatch.h>
#include <glob.h>
#include <wordexp.h>

#define __WORDEXP_FULL
//#undef __WORDEXP_FULL

/*
 * This is a recursive-descent-style word expansion routine.
 */

/* These variables are defined and initialized in the startup code.  */
//extern int __libc_argc;
//extern char **__libc_argv;

/* FIXME!!!! */
int __libc_argc;
char **__libc_argv;

/* Some forward declarations */
static int parse_dollars(char **word, size_t * word_length,
						 size_t * max_length, const char *words,
						 size_t * offset, int flags, wordexp_t * pwordexp,
						 const char *ifs, const char *ifs_white,
						 int quoted);
static int parse_backtick(char **word, size_t * word_length,
						  size_t * max_length, const char *words,
						  size_t * offset, int flags, wordexp_t * pwordexp,
						  const char *ifs, const char *ifs_white);
static int parse_dquote(char **word, size_t * word_length,
						size_t * max_length, const char *words,
						size_t * offset, int flags, wordexp_t * pwordexp,
						const char *ifs, const char *ifs_white);



/* The w_*() functions manipulate word lists. */
#define W_CHUNK	(100)

/* Result of w_newword will be ignored if it's the last word. */
static inline char *w_newword(size_t * actlen, size_t * maxlen)
{
	*actlen = *maxlen = 0;
	return NULL;
}

/* Add a character to the buffer, allocating room for it if needed.  */
static inline char *w_addchar(char *buffer, size_t * actlen,
							  size_t * maxlen, char ch)
	 /* (lengths exclude trailing zero) */
{

	if (*actlen == *maxlen) {
		char *old_buffer = buffer;
		assert(buffer == NULL || *maxlen != 0);
		*maxlen += W_CHUNK;
		buffer = realloc(buffer, 1 + *maxlen);
		if (buffer == NULL)
			free(old_buffer);
	}

	if (buffer != NULL) {
		buffer[*actlen] = ch;
		buffer[++(*actlen)] = '\0';
	}

	return buffer;
}

#define MAX( a, b ) ( ( ( a ) > ( b ) ) ? ( a ) : ( b ) )
static char *w_addmem(char *buffer, size_t * actlen, size_t * maxlen,
					  const char *str, size_t len)
{
	/* Add a string to the buffer, allocating room for it if needed.
	 */
	if (*actlen + len > *maxlen) {
		char *old_buffer = buffer;
		assert(buffer == NULL || *maxlen != 0);
		*maxlen += MAX(2 * len, W_CHUNK);
		buffer = realloc(old_buffer, 1 + *maxlen);
		if (buffer == NULL)
			free(old_buffer);
	}

	if (buffer != NULL) {
		*((char *) mempcpy(&buffer[*actlen], str, len)) = '\0';
		*actlen += len;
	}
	return buffer;
}

/* Add a string to the buffer, allocating room for it if needed.  */
static char *w_addstr(char *buffer, size_t * actlen, size_t * maxlen,
					  const char *str)
	 /* (lengths exclude trailing zero) */
{
	size_t len;
	assert(str != NULL);		/* w_addstr only called from this file */
	len = strlen(str);

	return w_addmem(buffer, actlen, maxlen, str, len);
}

/* Add a word to the wordlist */
static int w_addword(wordexp_t * pwordexp, char *word)
{
	size_t num_p;
	char **new_wordv;

	/* Internally, NULL acts like "".  Convert NULLs to "" before
	 * the caller sees them.
	 */
	if (word == NULL) {
		word = strdup("");
		if (word == NULL)
			goto no_space;
	}

	num_p = 2 + pwordexp->we_wordc + pwordexp->we_offs;
	new_wordv = realloc(pwordexp->we_wordv, sizeof(char *) * num_p);
	if (new_wordv != NULL) {
		pwordexp->we_wordv = new_wordv;
		pwordexp->we_wordv[pwordexp->we_offs + pwordexp->we_wordc++] = word;
		pwordexp->we_wordv[pwordexp->we_offs + pwordexp->we_wordc] = NULL;
		return 0;
	}

  no_space:
	return WRDE_NOSPACE;
}

/* The parse_*() functions should leave *offset being the offset in 'words'
 * to the last character processed.
 */
static int
parse_backslash(char **word, size_t * word_length, size_t * max_length,
				const char *words, size_t * offset)
{
	/* We are poised _at_ a backslash, not in quotes */

	switch (words[1 + *offset]) {
	case 0:
		/* Backslash is last character of input words */
		return WRDE_SYNTAX;

	case '\n':
		++(*offset);
		break;

	default:
		*word = w_addchar(*word, word_length, max_length, words[1 + *offset]);
		if (*word == NULL)
			return WRDE_NOSPACE;

		++(*offset);
		break;
	}

	return 0;
}

static int
parse_qtd_backslash(char **word, size_t * word_length, size_t * max_length,
					const char *words, size_t * offset)
{
	/* We are poised _at_ a backslash, inside quotes */

	switch (words[1 + *offset]) {
	case 0:
		/* Backslash is last character of input words */
		return WRDE_SYNTAX;

	case '\n':
		++(*offset);
		break;

	case '$':
	case '`':
	case '"':
	case '\\':
		*word =
			w_addchar(*word, word_length, max_length, words[1 + *offset]);
		if (*word == NULL)
			return WRDE_NOSPACE;

		++(*offset);
		break;

	default:
		*word = w_addchar(*word, word_length, max_length, words[*offset]);
		if (*word != NULL)
			*word =
				w_addchar(*word, word_length, max_length,
						  words[1 + *offset]);

		if (*word == NULL)
			return WRDE_NOSPACE;

		++(*offset);
		break;
	}

	return 0;
}

static int
parse_tilde(char **word, size_t * word_length, size_t * max_length,
			const char *words, size_t * offset, size_t wordc)
{
	/* We are poised _at_ a tilde */
	size_t i;

	if (*word_length != 0) {
		if (!((*word)[*word_length - 1] == '=' && wordc == 0)) {
			if (!((*word)[*word_length - 1] == ':'
				  && strchr(*word, '=') && wordc == 0)) {
				*word = w_addchar(*word, word_length, max_length, '~');
				return *word ? 0 : WRDE_NOSPACE;
			}
		}
	}

	for (i = 1 + *offset; words[i]; i++) {
		if (words[i] == ':' || words[i] == '/' || words[i] == ' ' ||
			words[i] == '\t' || words[i] == 0)
			break;

		if (words[i] == '\\') {
			*word = w_addchar(*word, word_length, max_length, '~');
			return *word ? 0 : WRDE_NOSPACE;
		}
	}

	if (i == 1 + *offset) {
		/* Tilde appears on its own */
		uid_t uid;
		struct passwd pwd, *tpwd;
		int buflen = 1000;
		char *home;
		char *buffer;
		int result;

		/* POSIX.2 says ~ expands to $HOME and if HOME is unset the
		   results are unspecified.  We do a lookup on the uid if
		   HOME is unset. */

		home = getenv("HOME");
		if (home != NULL) {
			*word = w_addstr(*word, word_length, max_length, home);
			if (*word == NULL)
				return WRDE_NOSPACE;
		} else {
			uid = getuid();
			buffer = alloca(buflen);

			while ((result = getpwuid_r(uid, &pwd, buffer, buflen, &tpwd)) 
					!= 0 && errno == ERANGE) 
			{
				buflen += 1000;
				buffer = alloca(buflen);
			}

			if (result == 0 && tpwd != NULL && pwd.pw_dir != NULL) {
				*word = w_addstr(*word, word_length, max_length, pwd.pw_dir);
				if (*word == NULL)
					return WRDE_NOSPACE;
			} else {
				*word = w_addchar(*word, word_length, max_length, '~');
				if (*word == NULL)
					return WRDE_NOSPACE;
			}
		}
	} else {
		/* Look up user name in database to get home directory */
		char *user = strndup(&words[1 + *offset], i - (1 + *offset));
		struct passwd pwd, *tpwd;
		int buflen = 1000;
		char *buffer = alloca(buflen);
		int result;

		while ((result = getpwnam_r(user, &pwd, buffer, buflen, &tpwd)) != 0
			   && errno == ERANGE) {
			buflen += 1000;
			buffer = alloca(buflen);
		}

		if (result == 0 && tpwd != NULL && pwd.pw_dir)
			*word = w_addstr(*word, word_length, max_length, pwd.pw_dir);
		else {
			/* (invalid login name) */
			*word = w_addchar(*word, word_length, max_length, '~');
			if (*word != NULL)
				*word = w_addstr(*word, word_length, max_length, user);
		}

		*offset = i - 1;
	}
	return *word ? 0 : WRDE_NOSPACE;
}


static int
do_parse_glob(const char *glob_word, char **word, size_t * word_length,
			  size_t * max_length, wordexp_t * pwordexp, const char *ifs,
			  const char *ifs_white)
{
	int error;
	int match;
	glob_t globbuf;

	error = glob(glob_word, GLOB_NOCHECK, NULL, &globbuf);

	if (error != 0) {
		/* We can only run into memory problems.  */
		assert(error == GLOB_NOSPACE);
		return WRDE_NOSPACE;
	}

	if (ifs && !*ifs) {
		/* No field splitting allowed. */
		assert(globbuf.gl_pathv[0] != NULL);
		*word = w_addstr(*word, word_length, max_length, globbuf.gl_pathv[0]);
		for (match = 1; match < globbuf.gl_pathc && *word != NULL; ++match) {
			*word = w_addchar(*word, word_length, max_length, ' ');
			if (*word != NULL)
				*word = w_addstr(*word, word_length, max_length,
								 globbuf.gl_pathv[match]);
		}

		globfree(&globbuf);
		return *word ? 0 : WRDE_NOSPACE;
	}

	assert(ifs == NULL || *ifs != '\0');
	if (*word != NULL) {
		free(*word);
		*word = w_newword(word_length, max_length);
	}

	for (match = 0; match < globbuf.gl_pathc; ++match) {
		char *matching_word = strdup(globbuf.gl_pathv[match]);

		if (matching_word == NULL || w_addword(pwordexp, matching_word)) {
			globfree(&globbuf);
			return WRDE_NOSPACE;
		}
	}

	globfree(&globbuf);
	return 0;
}

static int
parse_glob(char **word, size_t * word_length, size_t * max_length,
		   const char *words, size_t * offset, int flags,
		   wordexp_t * pwordexp, const char *ifs, const char *ifs_white)
{
	/* We are poised just after a '*', a '[' or a '?'. */
	int error = WRDE_NOSPACE;
	int quoted = 0;				/* 1 if singly-quoted, 2 if doubly */
	int i;
	wordexp_t glob_list;		/* List of words to glob */

	glob_list.we_wordc = 0;
	glob_list.we_wordv = NULL;
	glob_list.we_offs = 0;
	for (; words[*offset] != '\0'; ++*offset) {
		if ((ifs && strchr(ifs, words[*offset])) ||
			(!ifs && strchr(" \t\n", words[*offset])))
			/* Reached IFS */
			break;

		/* Sort out quoting */
		if (words[*offset] == '\'') {
			if (quoted == 0) {
				quoted = 1;
				continue;
			} else if (quoted == 1) {
				quoted = 0;
				continue;
			}
		} else if (words[*offset] == '"') {
			if (quoted == 0) {
				quoted = 2;
				continue;
			} else if (quoted == 2) {
				quoted = 0;
				continue;
			}
		}

		/* Sort out other special characters */
		if (quoted != 1 && words[*offset] == '$') {
			error = parse_dollars(word, word_length, max_length, words,
								  offset, flags, &glob_list, ifs,
								  ifs_white, quoted == 2);
			if (error)
				goto tidy_up;

			continue;
		} else if (words[*offset] == '\\') {
			if (quoted)
				error = parse_qtd_backslash(word, word_length, max_length,
											words, offset);
			else
				error = parse_backslash(word, word_length, max_length,
										words, offset);

			if (error)
				goto tidy_up;

			continue;
		}

		*word = w_addchar(*word, word_length, max_length, words[*offset]);
		if (*word == NULL)
			goto tidy_up;
	}

	/* Don't forget to re-parse the character we stopped at. */
	--*offset;

	/* Glob the words */
	error = w_addword(&glob_list, *word);
	*word = w_newword(word_length, max_length);
	for (i = 0; error == 0 && i < glob_list.we_wordc; i++)
		error = do_parse_glob(glob_list.we_wordv[i], word, word_length,
							  max_length, pwordexp, ifs, ifs_white);

	/* Now tidy up */
  tidy_up:
	wordfree(&glob_list);
	return error;
}

static int
parse_squote(char **word, size_t * word_length, size_t * max_length,
			 const char *words, size_t * offset)
{
	/* We are poised just after a single quote */
	for (; words[*offset]; ++(*offset)) {
		if (words[*offset] != '\'') {
			*word = w_addchar(*word, word_length, max_length, words[*offset]);
			if (*word == NULL)
				return WRDE_NOSPACE;
		} else
			return 0;
	}

	/* Unterminated string */
	return WRDE_SYNTAX;
}

#ifdef __WORDEXP_FULL
static int eval_expr(char *expr, long int *result);

static char *_itoa(unsigned long long int value, char *buflim)
{
	sprintf(buflim, "%llu", value);
	return buflim;
}

/* Functions to evaluate an arithmetic expression */
static int eval_expr_val(char **expr, long int *result)
{
	int sgn = +1;
	char *digit;

	/* Skip white space */
	for (digit = *expr; digit && *digit && isspace(*digit); ++digit);

	switch (*digit) {
	case '(':

		/* Scan for closing paren */
		for (++digit; **expr && **expr != ')'; ++(*expr));

		/* Is there one? */
		if (!**expr)
			return WRDE_SYNTAX;

		*(*expr)++ = 0;

		if (eval_expr(digit, result))
			return WRDE_SYNTAX;

		return 0;

	case '+':					/* Positive value */
		++digit;
		break;

	case '-':					/* Negative value */
		++digit;
		sgn = -1;
		break;

	default:
		if (!isdigit(*digit))
			return WRDE_SYNTAX;
	}

	*result = 0;
	for (; *digit && isdigit(*digit); ++digit)
		*result = (*result * 10) + (*digit - '0');

	*expr = digit;
	*result *= sgn;
	return 0;
}

static int eval_expr_multdiv(char **expr, long int *result)
{
	long int arg;

	/* Read a Value */
	if (eval_expr_val(expr, result) != 0)
		return WRDE_SYNTAX;

	while (**expr) {
		/* Skip white space */
		for (; *expr && **expr && isspace(**expr); ++(*expr));

		if (**expr == '*') {
			++(*expr);
			if (eval_expr_val(expr, &arg) != 0)
				return WRDE_SYNTAX;