/**
 * @PROJECT			CGI Bash Shell Interface
 * @COPYRIGHT		See COPYING in the top level directory
 * @FILE			cbsi.c
 * @PURPOSE			Common CBSI
 * @DEVELOPERS		Nathan Angelacos <nangel@users.sourceforge.net>
 *					Rafal Kupiec <belliash@asiotec.eu.org>
 */

#include <stdio.h>
#include <unistd.h>
#include <time.h>
#include <getopt.h>
#include <sys/mman.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <sys/stat.h>
#include <sys/fcntl.h>
#include <stdlib.h>
#include <string.h>
#include <grp.h>

#include "common.h"
#include "error.h"
#include "buffer.h"
#include "subshell.h"
#include "mimetype.h"
#include "cbsi.h"

struct option ga_long_options[] = {
	{"language-dir", required_argument, 0, 'l'},
	{"translation", required_argument, 0, 't'},
	{"upload-limit", required_argument, 0, 'u'},
	{"upload-dir", required_argument, 0, 'd'},
	{"shell", required_argument, 0, 's'},
	{0, 0, 0, 0}
};

const char *gs_short_options = "+u:d:l:t:s:";

int argc_argv(char* instr, argv_t** argv) {
	char quote = '\0';
	int arg_count = 0;
	enum state_t { WHITESPACE, WORDSPACE, TOKENSTART } state = WHITESPACE;
	argv_t* argv_array = NULL;
	int argc_slots = 0;
	size_t len, pos;

	len = strlen(instr);
	pos = 0;
	while(pos < len) {
		switch(*instr) {
			case '"':
			case '\'':
				if(state == WHITESPACE) {
					quote = *instr;
					state = TOKENSTART;
					if(*(instr + 1) == quote) {
						quote = '\0';
						*instr = '\0';
						argv_array[arg_count].quoted = -1;
					} else {
						instr++;
						pos++;
					}
				} else {
					if(*instr == quote) {
						argv_array[arg_count - 1].quoted = -1;
						quote = '\0';
						*instr = '\0';
						state = WHITESPACE;
					}
				}
				break;
			case '\\':
				if((quote) && (*(instr + 1) == quote)) {
					memmove(instr, instr + 1, strlen(instr));
					len--;
				} else {
					if(state == WHITESPACE) {
						state = TOKENSTART;
					}
				}
				break;
			case ' ':
			case '\t':
			case '\r':
			case '\n':
				if((state == WORDSPACE) && (quote == '\0')) {
					state = WHITESPACE;
					*instr = '\0';
				}
				break;
			case '\0':
				break;
			default:
				if(state == WHITESPACE) {
					state = TOKENSTART;
				}
		}
		if(state == TOKENSTART) {
			arg_count++;
			if(arg_count > argc_slots) {
				argc_slots += ALLOC_CHUNK;
				argv_array = (argv_t*) xrealloc(argv_array, sizeof(argv_t) * (argc_slots + ALLOC_CHUNK));
			}
			if(argv_array == NULL) {
				return -1;
			}
			argv_array[arg_count - 1].string = instr;
			argv_array[arg_count].quoted = 0;
			state = WORDSPACE;
		}
		instr++;
		pos++;
	}
	argv_array[arg_count].string = NULL;
	*argv = argv_array;
	return arg_count;
}

void assignGlobalStartupValues() {
	global.uploadkb = -1;
	global.shell = SUBSHELL_CMD;
	global.langdir = LANGDIR;
	global.translation = NULL;
	global.uploaddir = TEMPDIR;
	global.uploadlist = NULL;
	global.file_prefix = "FILE_";
	global.filename_prefix = "FILENAME_";
	global.get_prefix = "GET_";
	global.post_prefix = "POST_";
	global.cbsi_prefix = "CBSI_";
	global.cookie_prefix = "COOKIE_";
	global.null_prefix = "";
}

int BecomeUser(uid_t uid, gid_t gid) {
	if(getuid() == 0) {
		setgroups(1, &gid);
	}
	setgid(gid);
	setgid(getgid());
	setuid(uid);
	setuid(getuid());
	return 0;
}

void cbsiflags(list_t* env) {
	char buf[200];

	snprintf(buf, 200, "UPLOAD_DIR=%s", global.uploaddir);
	myputenv(env, buf, global.cbsi_prefix);
	snprintf(buf, 200, "UPLOAD_LIMIT=%lu", global.uploadkb);
	myputenv(env, buf, global.cbsi_prefix);
	snprintf(buf, 200, "SHELL=%s", global.shell);
	myputenv(env, buf, global.cbsi_prefix);
}

void cleanup(void) {
	int i;

	if(global.uploadlist) {
		unlink_uploadlist();
		free_token_list(global.uploadlist);
		global.uploadlist = NULL;
	}
	if(language != NULL && translations > 0) {
		for (i = 0; i < HASH_BUF; ++i) {
			if(ltable[i]) {
				free(ltable[i]->msgid);
				free(ltable[i]->msgstr);
				free(ltable[i]);
			}
		}
	}
}

void CookieVars(list_t* env) {
	char* qs;
	char* token;

	if(getenv("HTTP_COOKIE") != NULL) {
		qs = strdup(getenv("HTTP_COOKIE"));
	} else {
		return;
	}
	token = strtok(qs, ";");
	while(token) {
		while(token[0] == ' ') {
			token++;
		}
		myputenv(env, token, global.cookie_prefix);
		token = strtok(NULL, ";");
	}
	free(qs);
}

int count_lines(char* instr, size_t len, char* where) {
	size_t line = 1;

	while((where > instr) && (len)) {
		if(*instr == '\n') {
			line++;
		}
		len--;
		instr++;
	}
	return line;
}

char* find_whitespace(char* instr) {
	while(!isspace(*instr) && *instr) {
		instr++;
	}
	return instr;
}

void free_list_chain(list_t* list) {
	list_t *next;

	while(list) {
		next = list->next;
		free(list->buf);
		free(list);
		list = next;
	}
}

unsigned short generateHash(char* str) {
	unsigned long hash = 5381;
	int c;

	while(c = *str++) {
		hash = ((hash << 5) + hash) + c;
	}
	return hash % HASH_BUF;
}

void loadDictionary(const char* filename) {
	char* b;
	FILE* fp;
	short hash;
	char msgid[TRANS_BUF];
	char msgstr[TRANS_BUF];
	lstr* p;
	lstr* s;

	sprintf(buffer, "%s/%s/%s.dic", global.langdir, language, filename);
	if((fp = fopen(buffer, "r")) != NULL) {
		memset(ltable, 0, sizeof(lstr*) * HASH_BUF);
		memset(msgid, '\0', TRANS_BUF);
		memset(msgstr, '\0', TRANS_BUF);
		while(!feof(fp) && (fgets(buffer, TRANS_BUF - 1, fp) != NULL)) {
			b = skip_whitespace(buffer);
			if((!*b) || (*b == '#')) {
				continue;
			}
			if(strstr(b, "msgid") != NULL) {
				b = trim(b + 5);
				strncpy(msgid, b, strlen(b) + 1);
			} else if(strstr(b, "msgstr") != NULL) {
				b = trim(b + 6);
				strncpy(msgstr, b, strlen(b) + 1);
			} else {
				continue;
			}
			if(msgid[0] != 0 && msgstr[0] != 0) {
				hash = generateHash(msgid);
				s = malloc(sizeof(lstr));
				s->msgid = (char*) malloc(strlen(msgid) + 1);
				s->msgstr = (char*) malloc(strlen(msgstr) + 1);
				strcpy(s->msgid, msgid);
				strcpy(s->msgstr, msgstr);
				s->next = NULL;
				if(ltable[hash] == NULL) {
					ltable[hash] = s;
				} else {
					for(p = ltable[hash]; p->next != NULL; p = p->next);
					p->next = s;
				}
				translations++;
				msgid[0] = 0;
				msgstr[0] = 0;
			}
		}
		fclose(fp);
	}
}

void lowercase(char* instr) {
	while(*instr != '\0') {
		*instr = tolower (*instr);
		instr++;
	}
}

int main(int argc, char* argv[]) {
	token_t* tokenchain = NULL;
	buffer_t script_text;
	script_t* scriptchain;
	int retval = 0;
	char* filename = NULL;
	argv_t* av = NULL;
	char** av2 = argv;
	int av2c = argc;
	int command;
	int count;
	list_t* env = NULL;

	if(atexit(cleanup) != 0) {
		die_with_message(NULL, NULL, "atexit() failed");
	}
	assignGlobalStartupValues();
	buffer_init(&script_text);
	switch(argc) {
		case 1:
			puts("This is CBSI version " CBSI_VERSION "\nThis program runs as a CGI interface, not interactively.\n");
			return 0;
			break;
		default:
			command = argc_argv(argv[1], &av);
			if(command > 1) {
				av2c = argc - 1 + command;
				av2 = xmalloc(sizeof(char*) * av2c);
				av2[0] = argv[0];
				for(count = 1; count <= command; count++) {
					av2[count] = av[count - 1].string;
				}
				for(; count < av2c; count++) {
					av2[count] = argv[count - command + 1];
				}
			}
			parseCommandLine(av2c, av2);
			free(av);
			if(av2 != argv) {
				free(av2);
			}
			if(optind < av2c) {
				filename = av2[optind];
			} else {
				die_with_message(NULL, NULL, "No script file specified");
			}
			break;
	}
	scriptchain = load_script(filename, NULL);
	BecomeUser(scriptchain->uid, scriptchain->gid);
	env = wcversion(env);
	readenv(env);
	sessionid(env);
	cbsiflags(env);
	prepareDictionary();
	tokenchain = build_token_list(scriptchain, NULL);
	preprocess_token_list(tokenchain);
	CookieVars(env);
	ReadCGIPOSTValues(env);
	ReadCGIQueryString(env);
	process_token_list(&script_text, tokenchain);
	subshell_setup(global.shell, env);
	subshell_doscript(&script_text, scriptchain->name);
	subshell_destroy();
	buffer_destroy(&script_text);
	free_token_list(tokenchain);
	free_list_chain(env);
	free_script_list(scriptchain);
	return 0;
}

list_t* myputenv(list_t* cur, char* str, char* prefix) {
	list_t* prev = NULL;
	size_t keylen;
	char* entry = NULL;
	char* temp = NULL;
	int array = 0;
	int len;

	temp = memchr(str, '=', strlen(str));
	if(temp == 0) {
		return cur;
	}
	keylen = (size_t) (temp - str);
	if(memcmp(str + keylen - 2, "[]", 2) == 0) {
		keylen = keylen - 2;
		array = 1;
	}
	entry = xmalloc(strlen (str) + strlen(prefix) + 1);
	entry[0] = '\0';
	if(strlen(prefix)) {
		strncat(entry, prefix, strlen(prefix));
	}
	if(array == 1) {
		strncat(entry, str, keylen);
		strcat(entry, str + keylen + 2);
	} else {
		strcat(entry, str);
	}
	len = keylen + strlen(prefix) + 1;
	while(cur != NULL) {
		if(memcmp(cur->buf, entry, len) == 0) {
			if(array == 1) {
				temp = xmalloc(strlen(cur->buf) + strlen(entry) - len + 2);
				memmove(temp, cur->buf, strlen(cur->buf) + 1);
				strcat(temp, "\n");
				strcat(temp, str + keylen + 3);
				free(entry);
				entry = temp;
			}
			free(cur->buf);
			if(prev != NULL) {
				prev->next = cur->next;
			}
			free(cur);
			cur = prev;
		}
		prev = cur;
		if(cur) {
			cur = (list_t*) cur->next;
		}
	}
	cur = xmalloc(sizeof(list_t));
	cur->buf = entry;
	if(prev != NULL) {
		prev->next = cur;
	}
	return cur;
}

int parseCommandLine(int argc, char *argv[]) {
	int c;
	int option_index = 0;

	optopt = 0;
	optind = 0;
	while((c = getopt_long(argc, argv, gs_short_options, ga_long_options, &option_index)) != -1) {
		switch(c) {
			case 's':
				global.shell = optarg;
				break;
			case 'u':
				global.uploadkb = atoi (optarg);
				break;
			case 'l':
				global.langdir = optarg;
				break;
			case 't':
				global.translation = optarg;
				break;
			case 'd':
				global.uploaddir = optarg;
				break;
		}
	}
	return optind;
}

void prepareDictionary() {
	translations = 0;
	if(getenv("WWW_LANGUAGE") != NULL) {
		language = strdup(getenv("WWW_LANGUAGE"));
		if(global.translation != NULL) {
			loadDictionary(global.translation);
		} else {
			loadDictionary("common");
		}
	}
}

int ReadCGIPOSTValues(list_t* env) {
	size_t content_length = 0;
	size_t max_len;
	size_t i, j, x;
	sbuffer_t sbuf;
	buffer_t token;
	unsigned char* data;
	const char* CONTENT_LENGTH = "CONTENT_LENGTH";

	if((getenv(CONTENT_LENGTH) == NULL) || (strtoul(getenv(CONTENT_LENGTH), NULL, 10) == 0)) {
		return 0;
	}
	if(getenv("CONTENT_TYPE")) {
		if(strncasecmp(getenv("CONTENT_TYPE"), "multipart/form-data", 19) == 0) {
			i = rfc2388_handler(env);
			return i;
		}
	}
	sbuffer_init(&sbuf, 32768);
	sbuf.fh = STDIN;
	if(getenv(CONTENT_LENGTH)) {
		sbuf.maxread = strtoul(getenv(CONTENT_LENGTH), NULL, 10);
	}
	buffer_init(&token);
	max_len = ((global.uploadkb == 0) ? 2048 : abs(global.uploadkb)) * 1024;
	do {
		x = sbuffer_read(&sbuf, "&");
		content_length += sbuf.len;
		if(content_length >= max_len && global.uploadkb != -1) {
			die_with_message(NULL, NULL, "Attempted to send content larger than allowed limits.");
		}
		if((x == 0) || (token.data)) {
			buffer_add(&token, (char*) sbuf.segment, sbuf.len);
		}
		if(x) {
			data = sbuf.segment;
			sbuf.segment[sbuf.len] = '\0';
			if(token.data) {
				buffer_add(&token, sbuf.segment + sbuf.len, 1);
				data = token.data;
			}
			j = strlen((char*) data);
			for(i = 0; i <= j; i++) {
				if(data[i] == '+') {
					data[i] = ' ';
				}
			}
			unescape_url((char*) data);
			myputenv(env, (char*) data, global.post_prefix);
			if(token.data) {
				buffer_reset(&token);
			}
		}
	} while(!sbuf.eof);
	sbuffer_destroy(&sbuf);
	buffer_destroy(&token);
	return 0;
}

int ReadCGIQueryString(list_t* env) {
	char* qs;
	char* token;
	int i;

	if(getenv("QUERY_STRING") != NULL) {
		qs = strdup(getenv("QUERY_STRING"));
	} else {
		return 0;
	}
	for(i = 0; qs[i]; i++) {
		if(qs[i] == '+') {
			qs[i] = ' ';
		}
	}
	token = strtok(qs, "&;");
	while(token) {
		unescape_url(token);
		myputenv(env, token, global.get_prefix);
		token = strtok(NULL, "&;");
	}
	free(qs);
	return 0;
}

void readenv(list_t* env) {
	extern char** environ;
	int count = 0;

	while(environ[count] != NULL) {
		myputenv(env, environ[count], global.null_prefix);
		count++;
	}
}

void sessionid(list_t* env) {
	char session[29];

	sprintf(session, "SESSIONID=%x%x", getpid(), (int) time(NULL));
	myputenv(env, session, global.cbsi_prefix);
}

char* skip_whitespace(char* instr) {
	while(isspace(*instr) && *instr) {
		instr++;
	}
	return instr;
}

char* trim(char* str) {
	char* end;

	while(isspace(*str) || *str == '"') {
		str++;
	}
	if(*str == 0) {
		return str;
	}
	end = str + strlen(str) - 1;
	while(end > str && (isspace(*end) || *end == '"')) {
		end--;
	}
	*(end + 1) = 0;
	return str;
}

void unescape_url(char* url) {
	int i, j;

	for(i = 0, j = 0; url[j]; ++i, ++j) {
		if((url[i] = url[j]) != '%') {
			continue;
		}
		if(!url[j + 1] || !url[j + 2]) {
			break;
		}
		url[i] = x2c(&url[j + 1]);
		j += 2;
	}
	url[i] = '\0';
}

void unlink_uploadlist() {
	token_t* me;
	me = global.uploadlist;

	while(me) {
		unlink(me->buf);
		free(me->buf);
		me = me->next;
	}
}

void uppercase(char* instr) {
	while(*instr != '\0') {
		*instr = toupper(*instr);
		instr++;
	}
}

list_t* wcversion(list_t* env) {
	char version[200];

	sprintf(version, "VERSION=%s", CBSI_VERSION);
	return(myputenv(env, version, global.cbsi_prefix));
}

char x2c(char* what) {
	char digit;

	digit = (what[0] >= 'A' ? ((what[0] & 0xdf) - 'A') + 10 : (what[0] - '0'));
	digit *= 16;
	digit += (what[1] >= 'A' ? ((what[1] & 0xdf) - 'A') + 10 : (what[1] - '0'));
	return digit;
}

void* xmalloc(size_t size) {
	void* buf;

	if((buf = malloc(size)) == NULL) {
		die_with_message(NULL, NULL, g_err_msg[E_MALLOC_FAIL]);
	}
	memset(buf, 0, size);
	return buf;
}

void* xrealloc(void* buf, size_t size) {
	if((buf = realloc(buf, size)) == NULL) {
		die_with_message(NULL, NULL, g_err_msg[E_MALLOC_FAIL]);
	}
	return buf;
}