getcap.c

早期freebsd实现

	if (r_end > rp)
		if ((record = 
		     realloc(record, (size_t)(rp - record))) == NULL) {
			errno = ENOMEM;
			return (-2);
		}
		
	*cap = record;
	if (tc_not_resolved)
		return (1);
	return (0);
}	

static int
cdbget(capdbp, bp, name)
	DB *capdbp;
	char **bp, *name;
{
	DBT key, data;
	char *buf;
	int st;

	key.data = name;
	key.size = strlen(name);

	for (;;) {
		/* Get the reference. */
		switch(capdbp->get(capdbp, &key, &data, 0)) {
		case -1:
			return (-2);
		case 1:
			return (-1);
		}

		/* If not an index to another record, leave. */
		if (((char *)data.data)[0] != SHADOW)
			break;

		key.data = (char *)data.data + 1;
		key.size = data.size - 1;
	}
	
	*bp = (char *)data.data + 1;
	return (((char *)(data.data))[0] == TCERR ? 1 : 0);
}

/*
 * Cgetmatch will return 0 if name is one of the names of the capability
 * record buf, -1 if not.
 */
int
cgetmatch(buf, name)
	char *buf, *name;
{
	register char *np, *bp;

	/*
	 * Start search at beginning of record.
	 */
	bp = buf;
	for (;;) {
		/*
		 * Try to match a record name.
		 */
		np = name;
		for (;;)
			if (*np == '\0')
				if (*bp == '|' || *bp == ':' || *bp == '\0')
					return (0);
				else
					break;
			else
				if (*bp++ != *np++)
					break;

		/*
		 * Match failed, skip to next name in record.
		 */
		bp--;	/* a '|' or ':' may have stopped the match */
		for (;;)
			if (*bp == '\0' || *bp == ':')
				return (-1);	/* match failed totally */
			else
				if (*bp++ == '|')
					break;	/* found next name */
	}
}





int
cgetfirst(buf, db_array)
	char **buf, **db_array;
{
	(void)cgetclose();
	return (cgetnext(buf, db_array));
}

static FILE *pfp;
static int slash;
static char **dbp;

int
cgetclose()
{
	if (pfp != NULL) {
		(void)fclose(pfp);
		pfp = NULL;
	}
	dbp = NULL;
	gottoprec = 0;
	slash = 0;
	return(0);
}

/*
 * Cgetnext() gets either the first or next entry in the logical database 
 * specified by db_array.  It returns 0 upon completion of the database, 1
 * upon returning an entry with more remaining, and -1 if an error occurs.
 */
int
cgetnext(bp, db_array)
        register char **bp;
	char **db_array;
{
	size_t len;
	int status, i, done;
	char *cp, *line, *rp, *np, buf[BSIZE], nbuf[BSIZE];
	u_int dummy;

	if (dbp == NULL)
		dbp = db_array;

	if (pfp == NULL && (pfp = fopen(*dbp, "r")) == NULL) {
		(void)cgetclose();
		return (-1);
	}
	for(;;) {
		if (toprec && !gottoprec) {
			gottoprec = 1;
			line = toprec;
		} else {
			line = fgetln(pfp, &len);
			if (line == NULL && pfp) {
				(void)fclose(pfp);
				if (ferror(pfp)) {
					(void)cgetclose();
					return (-1);
				} else {
					if (*++dbp == NULL) {
						(void)cgetclose();
						return (0);
					} else if ((pfp =
					    fopen(*dbp, "r")) == NULL) {
						(void)cgetclose();
						return (-1);
					} else
						continue;
				}
			} else
				line[len - 1] = '\0';
			if (len == 1) {
				slash = 0;
				continue;
			}
			if (isspace(*line) ||
			    *line == ':' || *line == '#' || slash) {
				if (line[len - 2] == '\\')
					slash = 1;
				else
					slash = 0;
				continue;
			}
			if (line[len - 2] == '\\')
				slash = 1;
			else
				slash = 0;
		}			


		/* 
		 * Line points to a name line.
		 */
		i = 0;
		done = 0;
		np = nbuf;
		for (;;) {
			for (cp = line; *cp != '\0'; cp++) {
				if (*cp == ':') {
					*np++ = ':';
					done = 1;
					break;
				}
				if (*cp == '\\')
					break;
				*np++ = *cp;
			}
			if (done) {
				*np = '\0';
				break;
			} else { /* name field extends beyond the line */
				line = fgetln(pfp, &len);
				if (line == NULL && pfp) {
					(void)fclose(pfp);
					if (ferror(pfp)) {
						(void)cgetclose();
						return (-1);
					}
				} else
					line[len - 1] = '\0';
			}
		}
		rp = buf;
		for(cp = nbuf; *cp != NULL; cp++)
			if (*cp == '|' || *cp == ':')
				break;
			else
				*rp++ = *cp;

		*rp = '\0';
		/* 
		 * XXX 
		 * Last argument of getent here should be nbuf if we want true
		 * sequential access in the case of duplicates.  
		 * With NULL, getent will return the first entry found
		 * rather than the duplicate entry record.  This is a 
		 * matter of semantics that should be resolved.
		 */
		status = getent(bp, &dummy, db_array, -1, buf, 0, NULL);
		if (status == -2 || status == -3)
			(void)cgetclose();

		return (status + 1);
	}
	/* NOTREACHED */
}

/*
 * Cgetstr retrieves the value of the string capability cap from the
 * capability record pointed to by buf.  A pointer to a decoded, NUL
 * terminated, malloc'd copy of the string is returned in the char *
 * pointed to by str.  The length of the string not including the trailing
 * NUL is returned on success, -1 if the requested string capability
 * couldn't be found, -2 if a system error was encountered (storage
 * allocation failure).
 */
int
cgetstr(buf, cap, str)
	char *buf, *cap;
	char **str;
{
	register u_int m_room;
	register char *bp, *mp;
	int len;
	char *mem;

	/*
	 * Find string capability cap
	 */
	bp = cgetcap(buf, cap, '=');
	if (bp == NULL)
		return (-1);

	/*
	 * Conversion / storage allocation loop ...  Allocate memory in
	 * chunks SFRAG in size.
	 */
	if ((mem = malloc(SFRAG)) == NULL) {
		errno = ENOMEM;
		return (-2);	/* couldn't even allocate the first fragment */
	}
	m_room = SFRAG;
	mp = mem;

	while (*bp != ':' && *bp != '\0') {
		/*
		 * Loop invariants:
		 *	There is always room for one more character in mem.
		 *	Mp always points just past last character in mem.
		 *	Bp always points at next character in buf.
		 */
		if (*bp == '^') {
			bp++;
			if (*bp == ':' || *bp == '\0')
				break;	/* drop unfinished escape */
			*mp++ = *bp++ & 037;
		} else if (*bp == '\\') {
			bp++;
			if (*bp == ':' || *bp == '\0')
				break;	/* drop unfinished escape */
			if ('0' <= *bp && *bp <= '7') {
				register int n, i;

				n = 0;
				i = 3;	/* maximum of three octal digits */
				do {
					n = n * 8 + (*bp++ - '0');
				} while (--i && '0' <= *bp && *bp <= '7');
				*mp++ = n;
			}
			else switch (*bp++) {
				case 'b': case 'B':
					*mp++ = '\b';
					break;
				case 't': case 'T':
					*mp++ = '\t';
					break;
				case 'n': case 'N':
					*mp++ = '\n';
					break;
				case 'f': case 'F':
					*mp++ = '\f';
					break;
				case 'r': case 'R':
					*mp++ = '\r';
					break;
				case 'e': case 'E':
					*mp++ = ESC;
					break;
				case 'c': case 'C':
					*mp++ = ':';
					break;
				default:
					/*
					 * Catches '\', '^', and
					 *  everything else.
					 */
					*mp++ = *(bp-1);
					break;
			}
		} else
			*mp++ = *bp++;
		m_room--;

		/*
		 * Enforce loop invariant: if no room left in current
		 * buffer, try to get some more.
		 */
		if (m_room == 0) {
			size_t size = mp - mem;

			if ((mem = realloc(mem, size + SFRAG)) == NULL)
				return (-2);
			m_room = SFRAG;
			mp = mem + size;
		}
	}
	*mp++ = '\0';	/* loop invariant let's us do this */
	m_room--;
	len = mp - mem - 1;

	/*
	 * Give back any extra memory and return value and success.
	 */
	if (m_room != 0)
		if ((mem = realloc(mem, (size_t)(mp - mem))) == NULL)
			return (-2);
	*str = mem;
	return (len);
}

/*
 * Cgetustr retrieves the value of the string capability cap from the
 * capability record pointed to by buf.  The difference between cgetustr()
 * and cgetstr() is that cgetustr does not decode escapes but rather treats
 * all characters literally.  A pointer to a  NUL terminated malloc'd 
 * copy of the string is returned in the char pointed to by str.  The 
 * length of the string not including the trailing NUL is returned on success,
 * -1 if the requested string capability couldn't be found, -2 if a system 
 * error was encountered (storage allocation failure).
 */
int
cgetustr(buf, cap, str)
	char *buf, *cap, **str;
{
	register u_int m_room;
	register char *bp, *mp;
	int len;
	char *mem;

	/*
	 * Find string capability cap
	 */
	if ((bp = cgetcap(buf, cap, '=')) == NULL)
		return (-1);

	/*
	 * Conversion / storage allocation loop ...  Allocate memory in
	 * chunks SFRAG in size.
	 */
	if ((mem = malloc(SFRAG)) == NULL) {
		errno = ENOMEM;
		return (-2);	/* couldn't even allocate the first fragment */
	}
	m_room = SFRAG;
	mp = mem;

	while (*bp != ':' && *bp != '\0') {
		/*
		 * Loop invariants:
		 *	There is always room for one more character in mem.
		 *	Mp always points just past last character in mem.
		 *	Bp always points at next character in buf.
		 */
		*mp++ = *bp++;
		m_room--;

		/*
		 * Enforce loop invariant: if no room left in current
		 * buffer, try to get some more.
		 */
		if (m_room == 0) {
			size_t size = mp - mem;

			if ((mem = realloc(mem, size + SFRAG)) == NULL)
				return (-2);
			m_room = SFRAG;
			mp = mem + size;
		}
	}
	*mp++ = '\0';	/* loop invariant let's us do this */
	m_room--;
	len = mp - mem - 1;

	/*
	 * Give back any extra memory and return value and success.
	 */
	if (m_room != 0)
		if ((mem = realloc(mem, (size_t)(mp - mem))) == NULL)
			return (-2);
	*str = mem;
	return (len);
}

/*
 * Cgetnum retrieves the value of the numeric capability cap from the
 * capability record pointed to by buf.  The numeric value is returned in
 * the long pointed to by num.  0 is returned on success, -1 if the requested
 * numeric capability couldn't be found.
 */
int
cgetnum(buf, cap, num)
	char *buf, *cap;
	long *num;
{
	register long n;
	register int base, digit;
	register char *bp;

	/*
	 * Find numeric capability cap
	 */
	bp = cgetcap(buf, cap, '#');
	if (bp == NULL)
		return (-1);

	/*
	 * Look at value and determine numeric base:
	 *	0x... or 0X...	hexadecimal,
	 * else	0...		octal,
	 * else			decimal.
	 */
	if (*bp == '0') {
		bp++;
		if (*bp == 'x' || *bp == 'X') {
			bp++;
			base = 16;
		} else
			base = 8;
	} else
		base = 10;

	/*
	 * Conversion loop ...
	 */
	n = 0;
	for (;;) {
		if ('0' <= *bp && *bp <= '9')
			digit = *bp - '0';
		else if ('a' <= *bp && *bp <= 'f')
			digit = 10 + *bp - 'a';
		else if ('A' <= *bp && *bp <= 'F')
			digit = 10 + *bp - 'A';
		else
			break;

		if (digit >= base)
			break;

		n = n * base + digit;
		bp++;
	}

	/*
	 * Return value and success.
	 */
	*num = n;
	return (0);
}


/*
 * Compare name field of record.
 */
static int
nfcmp(nf, rec)
	char *nf, *rec;
{
	char *cp, tmp;
	int ret;
	
	for (cp = rec; *cp != ':'; cp++)
		;
	
	tmp = *(cp + 1);
	*(cp + 1) = '\0';
	ret = strcmp(nf, rec);
	*(cp + 1) = tmp;

	return (ret);
}