shared/config-parser.c

/*
 * Copyright © 2011 Intel Corporation
 *
 * Permission to use, copy, modify, distribute, and sell this software and its
 * documentation for any purpose is hereby granted without fee, provided that
 * the above copyright notice appear in all copies and that both that copyright
 * notice and this permission notice appear in supporting documentation, and
 * that the name of the copyright holders not be used in advertising or
 * publicity pertaining to distribution of the software without specific,
 * written prior permission.  The copyright holders make no representations
 * about the suitability of this software for any purpose.  It is provided "as
 * is" without express or implied warranty.
 *
 * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
 * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
 * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
 * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF 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.
 */

#define _GNU_SOURCE   /* for stchrnul() */
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
#include <ctype.h>
#include <limits.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>

#include "config-parser.h"

static int
handle_key(const struct config_key *key, const char *value)
{
	char *end, *s;
	int i, len;
	unsigned int ui;
	
	switch (key->type) {
	case CONFIG_KEY_INTEGER:
		i = strtol(value, &end, 0);
		if (*end != '\n') {
			fprintf(stderr, "invalid integer: %s\n", value);
			return -1;
		}
		*(int *)key->data = i;
		return 0;

	case CONFIG_KEY_UNSIGNED_INTEGER:
		ui = strtoul(value, &end, 0);
		if (*end != '\n') {
			fprintf(stderr, "invalid integer: %s\n", value);
			return -1;
		}
		*(unsigned int *)key->data = ui;
		return 0;

	case CONFIG_KEY_STRING:
		len = strlen(value);
		while (len > 0 && isspace(value[len - 1]))
			len--;
		s = malloc(len + 1);
		if (s == NULL)
			return -1;
		memcpy(s, value, len);
		s[len] = '\0';
		*(char **)key->data = s;
		return 0;

	case CONFIG_KEY_BOOLEAN:
		if (strcmp(value, "false\n") == 0)
			*(int *)key->data = 0;
		else if (strcmp(value, "true\n") == 0)
			*(int *)key->data = 1;
		else {
			fprintf(stderr, "invalid bool: %s\n", value);
			return -1;
		}
		return 0;

	default:
		assert(0);
		break;
	}

	return -1;
}

int
parse_config_file(int fd,
		  const struct config_section *sections, int num_sections,
		  void *data)
{
	FILE *fp;
	char line[512], *p;
	const struct config_section *current = NULL;
	int i;

	if (fd == -1)
		return -1;

	fp = fdopen(dup(fd), "r");
	if (fp == NULL) {
            perror("couldn't open config file");
		return -1;
	}

	rewind(fp);

	while (fgets(line, sizeof line, fp)) {
		if (line[0] == '#' || line[0] == '\n') {
			continue;
		} if (line[0] == '[') {
			p = strchr(&line[1], ']');
			if (!p || p[1] != '\n') {
				fprintf(stderr, "malformed "
					"section header: %s\n", line);
				fclose(fp);
				return -1;
			}
			if (current && current->done)
				current->done(data);
			p[0] = '\0';
			for (i = 0; i < num_sections; i++) {
				if (strcmp(sections[i].name, &line[1]) == 0) {
					current = &sections[i];
					break;
				}
			}
			if (i == num_sections)
				current = NULL;
		} else if (p = strchr(line, '='), p != NULL) {
			if (current == NULL)
				continue;
			p[0] = '\0';
			for (i = 0; i < current->num_keys; i++) {
				if (strcmp(current->keys[i].name, line) == 0) {
					if (handle_key(&current->keys[i], &p[1]) < 0) {
						fclose(fp);
						return -1;
					}
					break;
				}
			}
		} else {
			fprintf(stderr, "malformed config line: %s\n", line);
			fclose(fp);
			return -1;
		}
	}

	if (current && current->done)
		current->done(data);

	fclose(fp);

	return 0;
}

int
open_config_file(const char *name)
{
	const char *config_dir  = getenv("XDG_CONFIG_HOME");
	const char *home_dir	= getenv("HOME");
	const char *config_dirs = getenv("XDG_CONFIG_DIRS");
	char path[PATH_MAX];
	const char *p, *next;
	int fd;

	/* Precedence is given to config files in the home directory,
	 * and then to directories listed in XDG_CONFIG_DIRS and
	 * finally to the current working directory. */

	/* $XDG_CONFIG_HOME */
	if (config_dir) {
		snprintf(path, sizeof path, "%s/%s", config_dir, name);
		fd = open(path, O_RDONLY | O_CLOEXEC);
		if (fd >= 0)
			return fd;
	}

	/* $HOME/.config */
	if (home_dir) {
		snprintf(path, sizeof path, "%s/.config/%s", home_dir, name);
		fd = open(path, O_RDONLY | O_CLOEXEC);
		if (fd >= 0)
			return fd;
	}

	/* For each $XDG_CONFIG_DIRS: weston/<config_file> */
	if (!config_dirs)
		config_dirs = "/etc/xdg";  /* See XDG base dir spec. */

	for (p = config_dirs; *p != '\0'; p = next) {
		next = strchrnul(p, ':');
		snprintf(path, sizeof path,
			 "%.*s/weston/%s", (int)(next - p), p, name);
		fd = open(path, O_RDONLY | O_CLOEXEC);
		if (fd >= 0)
			return fd;

		if (*next == ':')
			next++;
	}

	/* Current working directory. */
	snprintf(path, sizeof path, "./%s", name);
	fd = open(path, O_RDONLY | O_CLOEXEC);

	if (fd >= 0)
		fprintf(stderr,
			"using config in current working directory: %s\n",
			path);
	else
		fprintf(stderr, "config file \"%s\" not found.\n", name);

	return fd;
}