/*
 * misc.c
 *
 * Miscellaneous macro's and functions.
 *
 * Copyright (C) 2004,2005 Martin Schlemmer <azarah@nosferatu.za.org>
 *
 *
 *      This program is free software; you can redistribute it and/or modify it
 *      under the terms of the GNU General Public License as published by the
 *      Free Software Foundation version 2 of the License.
 *
 *      This program 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
 *      General Public License for more details.
 *
 *      You should have received a copy of the GNU General Public License along
 *      with this program; if not, write to the Free Software Foundation, Inc.,
 *      675 Mass Ave, Cambridge, MA 02139, USA.
 *
 * $Header$
 */

#define _GNU_SOURCE

#include <errno.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/mman.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/param.h>
#include <dirent.h>
#include <unistd.h>
#include <fcntl.h>

#include "debug.h"
#include "misc.h"

char *memrepchr(char **str, char old, char new, size_t size) {
	char *str_p;

	if ((NULL == str) || (NULL == *str) || (0 == strlen(*str))) {
		DBG_MSG("Invalid argument passed!\n");
		return NULL;
	}

	str_p = memchr(*str, old, size);
	
	while (NULL != str_p) {
		str_p[0] = new;
		str_p = memchr(&str_p[1], old, size - (str_p - *str) - 1);
	}

	return *str;
}

char *strcatpaths(const char *pathname1, const char *pathname2) {
	char *new_path = NULL;
	int lenght;
	
	if ((NULL == pathname1) || (0 == strlen(pathname1)) ||
	    (NULL == pathname2) || (0 == strlen(pathname2))) {
		DBG_MSG("Invalid argument passed!\n");
		return NULL;
	}

	/* Lenght of pathname1 + lenght of pathname2 + '/' if needed */
	lenght = strlen(pathname1) + strlen(pathname2) + 1;
	/* lenght + '\0' */
	new_path = malloc(lenght + 1);
	if (NULL == new_path) {
		DBG_MSG("Failed to allocate buffer!\n");
		return NULL;
	}

	strncpy(new_path, pathname1, lenght);
	/* Should we add a '/' ? */
	if (new_path[strlen(new_path)-1] != '/')
		strncat(new_path, "/", lenght - strlen(new_path));
	strncat(new_path, pathname2, lenght - strlen(new_path));

	return new_path;
}

int exists(const char *pathname) {
	struct stat buf;
	int retval;

	if ((NULL == pathname) || (0 == strlen(pathname))) {
		DBG_MSG("Invalid argument passed!\n");
		return 0;
	}

	retval = lstat(pathname, &buf);
	if (-1 != retval)
		return 1;

	/* Clear errno, as we do not want debugging to trigger */
	errno = 0;

	return 0;
}

int is_file(const char *pathname, int follow_link) {
	struct stat buf;
	int retval;

	if ((NULL == pathname) || (0 == strlen(pathname))) {
		DBG_MSG("Invalid argument passed!\n");
		return 0;
	}

	retval = follow_link ? stat(pathname, &buf) : lstat(pathname, &buf);
	if ((-1 != retval) && (S_ISREG(buf.st_mode)))
		return 1;

	/* Clear errno, as we do not want debugging to trigger */
	errno = 0;

	return 0;
}

int is_link(const char *pathname) {
	struct stat buf;
	int retval;

	if ((NULL == pathname) || (0 == strlen(pathname))) {
		DBG_MSG("Invalid argument passed!\n");
		return 0;
	}

	retval = lstat(pathname, &buf);
	if ((-1 != retval) && (S_ISLNK(buf.st_mode)))
		return 1;

	/* Clear errno, as we do not want debugging to trigger */
	errno = 0;

	return 0;
}

int is_dir(const char *pathname, int follow_link) {
	struct stat buf;
	int retval;

	if ((NULL == pathname) || (0 == strlen(pathname))) {
		DBG_MSG("Invalid argument passed!\n");
		return 0;
	}

	retval = follow_link ? stat(pathname, &buf) : lstat(pathname, &buf);
	if ((-1 != retval) && (S_ISDIR(buf.st_mode)))
		return 1;

	/* Clear errno, as we do not want debugging to trigger */
	errno = 0;

	return 0;
}

time_t get_mtime(const char *pathname, int follow_link) {
	struct stat buf;
	int retval;

	if ((NULL == pathname) || (0 == strlen(pathname))) {
		DBG_MSG("Invalid argument passed!\n");
		return 0;
	}

	retval = follow_link ? stat(pathname, &buf) : lstat(pathname, &buf);
	if (-1 != retval)
		return buf.st_mtime;

	/* Clear errno, as we do not want debugging to trigger */
	errno = 0;

	return 0;
}

int mktree(const char *pathname, mode_t mode) {
	char *temp_name = NULL;
	char *temp_token = NULL;
	char *token_p;
	char *token;
	int retval;
	int lenght;

	if ((NULL == pathname) || (0 == strlen(pathname))) {
		DBG_MSG("Invalid argument passed!\n");
		errno = EINVAL;
		return -1;
	}

	/* Lenght of 'pathname' + extra for "./" if needed */
	lenght = strlen(pathname) + 2;
	/* lenght + '\0' */
	temp_name = malloc(lenght + 1);
	if (NULL == temp_name) {
		DBG_MSG("Failed to allocate temporary buffer!\n");
		return -1;
	}

	temp_token = strndup(pathname, strlen(pathname));
	if (NULL == temp_token) {
		DBG_MSG("Failed to allocate temporary buffer!\n");
		goto error;
	}
	token_p = temp_token;
	
	if (pathname[0] == '/')
		temp_name[0] = '\0';
	else
		/* If not an absolute path, make it local */
		strncpy(temp_name, ".", lenght);

	token = strsep(&token_p, "/");
	/* First token might be "", but that is OK as it will be when the
	 * pathname starts with '/' */
	while (NULL != token) {
		strncat(temp_name, "/", lenght - strlen(temp_name));
		strncat(temp_name, token, lenght - strlen(temp_name));

		/* If it does not exist, create the dir.  If it does exit,
		 * but is not a directory, we will catch it below. */
		if (!exists(temp_name)) {
			retval = mkdir(temp_name, mode);
			if (-1 == retval) {
				DBG_MSG("Failed to create directory!\n");
				goto error;
			}
		/* Not a directory or symlink pointing to a directory */
		} else if (!is_dir(temp_name, 1)) {
			DBG_MSG("Component in pathname is not a directory!\n");
			errno = ENOTDIR;
			goto error;
		}

		do {
			token = strsep(&token_p, "/");
		/* The first "" was Ok, but rather skip double '/' after that */
		} while ((NULL != token) && (0 == strlen(token)));
	}

	return 0;

error:
	free(temp_name);
	free(temp_token);
	
	return -1;
}

char **ls_dir(const char *pathname, int hidden) {
	DIR *dirfd;
	struct dirent *dir_entry;
	char **dirlist = NULL;

	if ((NULL == pathname) || (0 == strlen(pathname))) {
		DBG_MSG("Invalid argument passed!\n");
		errno = EINVAL;
		return NULL;
	}

	dirfd = opendir(pathname);
	if (NULL == dirfd) {
		DBG_MSG("Failed to call opendir()!\n");
		/* errno will be set by opendir() */
		goto error;
	}

	do {
		/* Clear errno to distinguish between EOF and error */
		errno = 0;
		dir_entry = readdir(dirfd);
		/* Only an error if 'errno' != 0, else EOF */
		if ((NULL == dir_entry) && (0 != errno)) {
			DBG_MSG("Failed to call readdir()!\n");
			goto error;
		}
		if ((NULL != dir_entry) &&
		    /* Should we display hidden files? */
		    (hidden ? 1 : dir_entry->d_name[0] != '.'))
		{
			char *d_name = dir_entry->d_name;
			char *tmp_p;
			
			tmp_p = strcatpaths(pathname, d_name);
			if (NULL == tmp_p) {
				DBG_MSG("Failed to allocate buffer!\n");
				/* errno = ENOMEM */
				goto error;
			}

			STRING_LIST_ADD(dirlist, tmp_p, error);
		}
	} while (NULL != dir_entry);

	if (NULL == dirlist[0]) {
		DBG_MSG("Directory is empty.");
		errno = ENOENT;
		goto error;
	}

	closedir(dirfd);
	
	return dirlist;

error:
	/* Free dirlist on error */
	STRING_LIST_FREE(dirlist);

	if (NULL != dirfd) {
		int old_errno = errno;
		closedir(dirfd);
		/* closedir() might have changed it */
		errno = old_errno;
	}

	return NULL;
}

/* This handles simple 'entry="bar"' type variables.  If it is more complex
 * ('entry="$(pwd)"' or such), it will obviously not work, but current behaviour
 * should be fine for the type of variables we want. */
char *get_cnf_entry(const char *pathname, const char *entry) {
	char *buf = NULL;
	char *tmp_buf = NULL;
	char *tmp_p;
	char *value = NULL;
	char *token;
	int lenght;
	int count;
	int current = 0;
			

	if ((NULL == pathname) || (0 == strlen(pathname)) ||
	    (NULL == entry) || (0 == strlen(entry))) {
		DBG_MSG("Invalid argument passed!\n");
		errno = EINVAL;
		return NULL;
	}

	/* If it is not a file or symlink pointing to a file, bail */
	if (!is_file(pathname, 1)) {
		DBG_MSG("Given pathname is not a file or do not exist!\n");
		/* FIXME: Might need to set this to something better? */
		errno = ENOENT;
		return NULL;
	}

	if (-1 == file_map(pathname, &buf, &lenght)) {
		DBG_MSG("Could not open config file for reading!\n");
		return NULL;
	}

	while (current < lenght) {
		count = buf_get_line(buf, lenght, current);

		tmp_buf = strndup(&buf[current], count);
		if (NULL == tmp_buf) {
			DBG_MSG("Failed to allocate temporary buffer!\n");
			goto error;
		}
		tmp_p = tmp_buf;
		
		/* Strip leading spaces/tabs */
		while ((tmp_p[0] == ' ') || (tmp_p[0] == '\t'))
			tmp_p++;

		/* Get entry and value */
		token = strsep(&tmp_p, "=");
		/* Bogus entry or value */
		if (NULL == token)
			goto _continue;

		/* Make sure we have a string that is larger than 'entry', and
		 * the first part equals 'entry' */
		if ((strlen(token) > 0) && (0 == strcmp(entry, token)))
		{
			do {
				/* Bash variables are usually quoted */
				token = strsep(&tmp_p, "\"\'");
			/* If quoted, the first match will be "" */
			} while ((NULL != token) && (0 == strlen(token)));

			/* We have a 'entry='.  We respect bash rules, so NULL
			 * value for now (if not already) */
			if (NULL == token) {
				/* We might have 'entry=' and later 'entry="bar"',
				 * so just continue for now ... we will handle
				 * it below when 'value == NULL' */
				if (NULL != value) {
					free(value);
					value = NULL;
				}
				goto _continue;
			}
			
			/* If we have already allocated 'value', free it */
			if (NULL != value)
				free(value);

			value = strndup(token, strlen(token));
			if (NULL == value)
				/* errno = ENOMEM */
				goto error;

			/* We do not break, as there might be more than one entry
			 * defined, and as bash uses the last, so should we */
			/* break; */
		}

_continue:
		current += count + 1;
		free(tmp_buf);
		/* Set to NULL in case we error out above and have
		 * to free below */
		tmp_buf = NULL;
	}
				

	if (NULL == value) {
		DBG_MSG("Failed to get value for config entry '%s'!\n", entry);
		errno = ENOENT;
		goto error;
	}

	file_unmap(buf, lenght);

	return value;

error:
	free(tmp_buf);
	free(value);

	if (NULL != buf) {
		int old_errno = errno;
		file_unmap(buf, lenght);
		/* unmmap() might have changed it */
		errno = old_errno;
	}

	return NULL;
}


/*
 * Below three functions (file_map, file_unmap and buf_get_line) are
 * from udev-050 (udev_utils.c).
 * (Some are slightly modified, please check udev for originals.)
 *
 * Copyright (C) 2004 Kay Sievers <kay@vrfy.org>
 *
 *	This program is free software; you can redistribute it and/or modify it
 *	under the terms of the GNU General Public License as published by the
 *	Free Software Foundation version 2 of the License.
 * 
 *	This program 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
 *	General Public License for more details.
 * 
 *	You should have received a copy of the GNU General Public License along
 *	with this program; if not, write to the Free Software Foundation, Inc.,
 *	675 Mass Ave, Cambridge, MA 02139, USA.
 *
 */

int file_map(const char *filename, char **buf, size_t *bufsize)
{
	struct stat stats;
	int fd;
	int old_errno;

	fd = open(filename, O_RDONLY);
	if (fd < 0) {
		DBG_MSG("Failed to open file!\n");
		return -1;
	}

	if (fstat(fd, &stats) < 0) {
		DBG_MSG("Failed to stat file!\n");
		old_errno = errno;
		close(fd);
		/* close() might have changed it */
		errno = old_errno;
		return -1;
	}

	*buf = mmap(NULL, stats.st_size, PROT_READ, MAP_SHARED, fd, 0);
	if (*buf == MAP_FAILED) {
		DBG_MSG("Failed to mmap file!\n");
		old_errno = errno;
		close(fd);
		/* close() might have changed it */
		errno = old_errno;
		return -1;
	}
	*bufsize = stats.st_size;

	close(fd);

	return 0;
}

void file_unmap(char *buf, size_t bufsize)
{
	munmap(buf, bufsize);
}

size_t buf_get_line(char *buf, size_t buflen, size_t cur)
{
	size_t count = 0;

	for (count = cur; count < buflen && buf[count] != '\n'; count++);

	return count - cur;
}