env.c

/* Copyright 1988,1990,1993,1994 by Paul Vixie
 * All rights reserved
 *
 * Distribute freely, except: don't remove my name from the source or
 * documentation (don't take credit for my work), mark your changes (don't
 * get me blamed for your possible bugs), don't alter or remove this
 * notice.  May be sold if buildable source is provided to buyer.  No
 * warrantee of any kind, express or implied, is included with this
 * software; use at your own risk, responsibility for damages (if any) to
 * anyone resulting from the use of this software rests entirely with the
 * user.
 *
 * Send bug reports, bug fixes, enhancements, requests, flames, etc., and
 * I'll try to keep a version up to date.  I can be reached as follows:
 * Paul Vixie          <paul@vix.com>          uunet!decwrl!vixie!paul
 */

#if !defined(lint) && !defined(LINT)
static char rcsid[] = "$Id: env.c,v 2.7 1994/01/26 02:25:50 vixie Exp vixie $";
#endif


#include "cron.h"


char **
env_init()
{
	register char	**p = (char **) malloc(sizeof(char **));

	if (p)
		p[0] = NULL;
	return (p);
}


void
env_free(envp)
	char	**envp;
{
	char	**p;

	if(!envp)
		return;

	for (p = envp;  *p;  p++)
		free(*p);
	free(envp);
}


char **
env_copy(envp)
	register char	**envp;
{
	register int	count, i;
	register char	**p;

	for (count = 0;  envp[count] != NULL;  count++)
		;
	p = (char **) malloc((count+1) * sizeof(char *));  /* 1 for the NULL */
	if (p == NULL) {
		errno = ENOMEM;
		return NULL;
	}
	for (i = 0;  i < count;  i++)
		if ((p[i] = strdup(envp[i])) == NULL) {
			while (--i >= 0)
				(void) free(p[i]);
			free(p);
			errno = ENOMEM;
			return NULL;
		}
	p[count] = NULL;
	return (p);
}


char **
env_set(envp, envstr)
	char	**envp;
	char	*envstr;
{
	register int	count, found;
	register char	**p;

	/*
	 * count the number of elements, including the null pointer;
	 * also set 'found' to -1 or index of entry if already in here.
	 */
	found = -1;
	for (count = 0;  envp[count] != NULL;  count++) {
		if (!strcmp_until(envp[count], envstr, '='))
			found = count;
	}
	count++;	/* for the NULL */

	if (found != -1) {
		/*
		 * it exists already, so just free the existing setting,
		 * save our new one there, and return the existing array.
		 */
		free(envp[found]);
		if ((envp[found] = strdup(envstr)) == NULL) {
			envp[found] = "";
			errno = ENOMEM;
			return NULL;
		}
		return (envp);
	}

	/*
	 * it doesn't exist yet, so resize the array, move null pointer over
	 * one, save our string over the old null pointer, and return resized
	 * array.
	 */
	p = (char **) realloc((void *) envp,
			      (unsigned) ((count+1) * sizeof(char **)));
	if (p == NULL) 	{
		errno = ENOMEM;
		return NULL;
	}
	p[count] = p[count-1];
	if ((p[count-1] = strdup(envstr)) == NULL) {
		errno = ENOMEM;
		return NULL;
	}
	return (p);
}

/* The following states are used by load_env(), traversed in order: */
enum env_state {
	NAMEI,		/* First char of NAME, may be quote */
	NAME,		/* Subsequent chars of NAME */
	EQ1,		/* After end of name, looking for '=' sign */
	EQ2,		/* After '=', skipping whitespace */
	VALUEI,		/* First char of VALUE, may be quote */
	VALUE,		/* Subsequent chars of VALUE */
	FINI,		/* All done, skipping trailing whitespace */
	ERROR,		/* Error */
};

/* return	ERR = end of file
 *		FALSE = not an env setting (file was repositioned)
 *		TRUE = was an env setting
 */
int
load_env(envstr, f)
	char	*envstr;
	FILE	*f;
{
	long	filepos;
	int	fileline;
	enum env_state state;
	char name[MAX_ENVSTR], val[MAX_ENVSTR];
	char quotechar, *c, *str;

	filepos = ftell(f);
	fileline = LineNumber;
	skip_comments(f);
	if (EOF == get_string(envstr, MAX_ENVSTR - 1, f, "\n"))
		return (ERR);

    envstr[MAX_ENVSTR - 1] = '\0';

	Debug(DPARS, ("load_env, read <%s>\n", envstr))

	bzero(name, sizeof name);
	bzero(val, sizeof val);
	str = name;
	state = NAMEI;
	quotechar = '\0';
	c = envstr;
	while (state != ERROR && *c) {
		switch (state) {
		case NAMEI:
		case VALUEI:
			if (*c == '\'' || *c == '"')
				quotechar = *c++;
			state++;
			/* FALLTHROUGH */
		case NAME:
		case VALUE:
			if (quotechar) {
				if (*c == quotechar) {
					state++;
					c++;
					break;
				}
				if (state == NAME && *c == '=') {
					state = ERROR;
					break;
				}
			} else {
				if (state == NAME) {
					if (isspace((unsigned char)*c)) {
						c++;
						state++;
						break;
					}
					if (*c == '=') {
						state++;
						break;
					}
				}
			}
			*str++ = *c++;
			break;

		case EQ1:
			if (*c == '=') {
				state++;
				str = val;
				quotechar = '\0';
			} else {
				if (!isspace((unsigned char)*c))
					state = ERROR;
			}
			c++;
			break;

		case EQ2:
		case FINI:
			if (isspace((unsigned char)*c))
				c++;
			else
				state++;
			break;

		default:
			abort();
		}
	}
	if (state != FINI && !(state == VALUE && !quotechar)) {
		Debug(DPARS, ("load_env, not an env var, state = %d\n", state))
		fseek(f, filepos, 0);
		Set_LineNum(fileline);
		return (FALSE);
	}
	if (state == VALUE) {
		/* End of unquoted value: trim trailing whitespace */
		c = val + strlen(val);
		while (c > val && isspace((unsigned char)c[-1]))
			*(--c) = '\0';
	}

	/* 2 fields from parser; looks like an env setting */

	/*
	 * This can't overflow because get_string() limited the size of the
	 * name and val fields.  Still, it doesn't hurt to be careful...
	 */
	/*local*/{
		int	len = strdtb(val);

		if (len >= 2) {
			if (val[0] == '\'' || val[0] == '"') {
				if (val[len-1] == val[0]) {
					val[len-1] = '\0';
					(void) strcpy(val, val+1);
				}
			}
		}
	}

	if (strlen(name) + 1 + strlen(val) >= MAX_ENVSTR-1)
		return (FALSE);
	(void) sprintf(envstr, "%s=%s", name, val);
	Debug(DPARS, ("load_env, <%s> <%s> -> <%s>\n", name, val, envstr))
	return (TRUE);
}

char *
env_get(name, envp)
	register char	*name;
	register char	**envp;
{
	register int	len = strlen(name);
	register char	*p, *q;

	while ((p = *envp++)) {
		if (!(q = strchr(p, '=')))
			continue;
		if ((q - p) == len && !strncmp(p, name, len))
			return (q+1);
	}
	return (NULL);
}