path: root/src/format.c

#include <sys/types.h>
#include <rpcsvc/yp.h>
#include <stdlib.h>
#include "defaults.h"
#include "format.h"
#include "plugin.h"

void
format_free_data(char *data)
{
	if (data != NULL) {
		free(data);
	}
}

void
format_free_ndn_list(char **ndn_list)
{
	if (ndn_list != NULL) {
		free(ndn_list);
	}
}

/* Retrieve a single value for an attribute.  If there are no values, or more
 * than one, fail. */
static char *
format_single(Slapi_PBlock *pb, Slapi_Entry *e, const char *attr,
	      char ***visited_ndns)
{
	char **values, *ret;
	int count;
	values = slapi_entry_attr_get_charray(e, attr);
	for (count = 0; (values != NULL) && (values[count] != NULL); count++) {
		continue;
	}
	if (count == 1) {
		ret = strdup(values[0]);
	} else {
		ret = NULL;
	}
	slapi_ch_array_free(values);
	return ret;
}

/* Find the matching closing marker. */
static const char *
format_find_closer(const char *pair, const char *pattern)
{
	int i, level = 0;
	for (i = 0; pattern[i] != '\0'; i++) {
		if (pattern[i] == pair[0]) {
			level++;
		} else {
			if (pattern[i] == pair[1]) {
				level--;
			}
		}
		if (level == 0) {
			return &pattern[i];
		}
	}
	return NULL;
}

/* Recursively expand the expression into the output buffer, adding any entries
 * we visit (other than e) to the list of visited NDNs.  Unless it's a literal,
 * treat the entire input format specifier as an expression. */
static int
format_expand(struct plugin_state *state, Slapi_PBlock *pb, Slapi_Entry *e,
	      const char *fmt,
	      char *outbuf, int outbuf_len,
	      char ***visited_ndns,
	      PRBool literal)
{
	int i, j;
	int exp_len, level;
	const char *fmtstart, *fmtend, *match, *attribute;
	char *tmp, *fnname, *spd_id;
	char exp[outbuf_len * 2];
	const char *default_value, *alternate_value, *paramstart, *paramend;
	size_t spn;

	spd_id = state->plugin_desc->spd_id;
	slapi_log_error(SLAPI_LOG_PLUGIN, spd_id,
			"expanding %s\"%s\"%s\n",
			literal ? "" : "%{", fmt, literal ? "" : "}");

	/* First, expand any subexpressions and call any "functions". */
	level = 0;
	i = 0;
	j = 0;
	while (fmt[i] != '\0') {
		switch (fmt[i]) {
		case '%':
			/* This might be a subexpression, a "function" call, or
			 * an escaped character. */
			switch (fmt[i + 1]) {
			case '%':
				/* It's just an escaped "%". */
				exp[j++] = '%';
				i += 2;
				continue;
				break;
			case '{':
				/* Find the beginning of the subexpression. */
				fmtstart = fmt + i;
				/* Find the end of the subexpression. */
				match = format_find_closer("{}", fmtstart + 1);
				if (match == NULL) {
					slapi_log_error(SLAPI_LOG_PLUGIN,
							spd_id,
							"expansion failed: "
							"no closing brace\n");
					return -1;
				} else {
					/* Mark the first character after the
					 * subexpression. */
					fmtend = match + 1;
					/* Make a copy of the subexpression. */
					tmp = malloc(fmtend - fmtstart);
					if (tmp == NULL) {
						slapi_log_error(SLAPI_LOG_PLUGIN,
								spd_id,
								"expansion "
								"failed: out "
								"of memory\n");
						return -1;
					}
					memcpy(tmp, fmtstart + 2,
					       fmtend - fmtstart - 3);
					tmp[fmtend - fmtstart - 3] = '\0';
					/* Recursively expand the
					 * subexpression. */
					exp_len = format_expand(state, pb, e,
								tmp,
								exp + j,
								sizeof(exp) - j,
								visited_ndns,
								FALSE);
					free(tmp);
					if ((exp_len < 0) ||
					    (exp_len + j >= (int) sizeof(exp))) {
						/* We'd be out of space,
						 * FAIL. */
						slapi_log_error(SLAPI_LOG_PLUGIN,
								spd_id,
								"expansion "
								"failed: result"
								" would be too "
								"big\n");
						return -1;
					} else {
						/* It fit, so keep going. */
						i = (match + 1) - fmt;
						j += exp_len;
					}
				}
				continue;
				break;
			default:
				/* Assume it's a "function" call.  Pick out the
				 * name of the function. */
				paramstart = strchr(fmt + i, '{');
				if (paramstart == NULL) {
					/* No start? Bad format. */
					slapi_log_error(SLAPI_LOG_PLUGIN,
							spd_id,
							"expansion failed: "
							"bad function "
							"invocation\n");
					return -1;
				}
				paramend = strchr(paramstart + 1, '}');
				if (paramend == NULL) {
					/* No matching end? Bad format. */
					slapi_log_error(SLAPI_LOG_PLUGIN,
							spd_id,
							"expansion failed: "
							"bad function "
							"invocation\n");
					return -1;
				}
				fnname = malloc(paramstart - (fmt + i));
				if (fnname == NULL) {
					/* Out of memory, FAIL. */
					slapi_log_error(SLAPI_LOG_PLUGIN,
							spd_id,
							"expansion failed: "
							"out of memory\n");
					return -1;
				}
				memcpy(fnname, fmt + i + 1,
				       paramstart - (fmt + i + 1));
				fnname[paramstart - (fmt + i + 1)] = '\0';
				/* Isolate the parameter string. */
				tmp = malloc(paramend - paramstart);
				if (tmp == NULL) {
					/* Out of memory, FAIL. */
					slapi_log_error(SLAPI_LOG_PLUGIN,
							spd_id,
							"expansion failed: "
							"out of memory\n");
					free(fnname);
					return -1;
				}
				memcpy(tmp, paramstart + 1,
				       paramend - (paramstart + 1));
				tmp[paramend - paramstart] = '\0';
				slapi_log_error(SLAPI_LOG_PLUGIN, spd_id,
						"calling \"%s\"(\"%s\")\n",
						fnname, tmp);
				free(fnname);
				free(tmp);
				i = (paramend - fmt) + 1;
				continue;
				break;
			}
			break;
		default:
			/* Default is just a literal character. */
			exp[j++] = fmt[i++];
			break;
		}
	}
	exp[j] = '\0';

	if (literal) {
		/* It's a literal string, so we're actually done. */
		i = strlen(exp);
		if (i <= outbuf_len) {
			memcpy(outbuf, exp, i);
		}
		slapi_log_error(SLAPI_LOG_PLUGIN, "nis-plugin",
				"expanded to \"%s\"\n", exp);
		return i;
	} else {
		/* It's an expression, so evaluate it. */
		slapi_log_error(SLAPI_LOG_PLUGIN, "nis-plugin",
				"looking up simple expression \%\{\"%s\"}\n", exp);
		/* Check if it uses a default/alternate value. */
		spn = strcspn(exp, ":");
		if (spn == strlen(exp)) {
			/* Simple expression: expect it to be a single-valued
			 * attribute. */
			tmp = format_single(pb, e, exp, visited_ndns);
			if (tmp != NULL) {
				/* Copy the string to the output buffer if
				 * there's space for it. */
				i = strlen(tmp);
				if (i <= outbuf_len) {
					memcpy(outbuf, tmp, i);
				}
				slapi_log_error(SLAPI_LOG_PLUGIN, "nis-plugin",
						"expanded to \"%s\"\n", tmp);
				free(tmp);
				/* Return the length of the expanded
				 * expression. */
				return i;
			} else {
				/* No value found? FAIL. */
				slapi_log_error(SLAPI_LOG_PLUGIN, "nis-plugin",
						"no value for \"%s\"\n", exp);
				return -1;
			}
		} else {
			/* Make a copy of the attribute name. */
			exp[spn] = '\0';
			attribute = exp;
			alternate_value = NULL;
			default_value = NULL;
			/* Figure out if there's an alternate or default value
			 * given. */
			switch (exp[spn + 1]) {
			case '+':
				alternate_value = exp + spn + 2;
				break;
			case '-':
				default_value = exp + spn + 2;
				break;
			default:
				default_value = exp + spn + 1;
				break;
			}
			/* Retrieve the value. */
			tmp = format_single(pb, e, attribute, visited_ndns);
			if (tmp == NULL) {
				/* The attribute is undefined, or we're
				 * treating it as if it is. */
				if (default_value != NULL) {
					/* Supply the default value. */
					i = strlen(default_value);
					if (i <= outbuf_len) {
						memcpy(outbuf, default_value,
						       i);
					}
					slapi_log_error(SLAPI_LOG_PLUGIN, "nis-plugin",
							"expanded to \"%s\"\n", default_value);
					return i;
				} else {
					/* No value, and no default: FAIL. */
		slapi_log_error(SLAPI_LOG_PLUGIN, "nis-plugin",
				"failed to expand: no valid value, no default\n");
					return -1;
				}
			} else {
				/* There's no value defined (or it's
				 * multi-valued, which is usually trouble). */
				if (alternate_value != NULL) {
					/* Supply the alternate value. */
					i = strlen(alternate_value);
					if (i <= outbuf_len) {
						memcpy(outbuf, alternate_value,
						       i);
					}
					slapi_log_error(SLAPI_LOG_PLUGIN, "nis-plugin",
							"expanded to \"%s\"\n", alternate_value);
					free(tmp);
					return i;
				} else {
					/* Supply the looked-up value. */
					i = strlen(tmp);
					if (i <= outbuf_len) {
						memcpy(outbuf, tmp, i);
					}
					slapi_log_error(SLAPI_LOG_PLUGIN, "nis-plugin",
							"expanded to \"%s\"\n", tmp);
					free(tmp);
					return i;
				}
			}
		}
	}
}

static char *
format_format(struct plugin_state *state, Slapi_PBlock *pb, Slapi_Entry *e,
	      const char *fmt, char ***visited_ndns)
{
	char buf[YPMAXRECORD], *tmp;
	const char *match, *fmtstart, *fmtend;
	unsigned int i, j;
	int exp_len;

	i = format_expand(state, pb, e, fmt, buf, sizeof(buf),
			  visited_ndns, TRUE);
	if (i < sizeof(buf)) {
		buf[i] = '\0';
		return strdup(buf);
	} else {
		return NULL;
	}
}

char *
format_get_data(struct plugin_state *state, Slapi_PBlock *pb, Slapi_Entry *e,
		const char *fmt, char ***visited_ndns)
{
	Slapi_PBlock *local_pb;
	char ***ndn_list, **local_ndn_list, *ret;

	/* Supply an NDN list if the caller didn't. */
	if (visited_ndns != NULL) {
		ndn_list = visited_ndns;
	} else {
		ndn_list = &local_ndn_list;
		local_ndn_list = NULL;
	}

	/* Supply a PBlock if the caller didn't. */
	if (pb == NULL) {
		local_pb = slapi_pblock_new();
		pb = local_pb;
	} else {
		local_pb = NULL;
	}

	ret = format_format(state, pb, e, fmt, ndn_list);

	/* If we supplied a PBlock, clean it up. */
	if (pb == local_pb) {
		slapi_pblock_destroy(local_pb);
	}
	/* If we supplied an NDN list, clean it up. */
	if (ndn_list == &local_ndn_list) {
		format_free_ndn_list(local_ndn_list);
	}

	return ret;
}