/*
 * tracelib.c
 * $Id$
 *
 * Copyright (c) 2007 Eugene Pimenov (GSoC), The MacPorts Project.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the MacPorts Team nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#if HAVE_CONFIG_H
#include <config.h>
#endif

#include <string.h>
#include <sys/time.h>
#include <sys/resource.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <sys/select.h>
#include <sys/un.h>
#include <stdarg.h>
#include <errno.h>
#include <pthread.h>
#include <limits.h>
#include "tracelib.h"

#ifndef HAVE_STRLCPY
/* Define strlcpy if it's not available. */
size_t strlcpy(char* dst, const char* src, size_t size);
size_t strlcpy(char* dst, const char* src, size_t size)
{
	size_t result = strlen(src);
	if (size > 0)
	{
		size_t copylen = size - 1;
		if (copylen > result)
		{
			copylen = result;
		}
		memcpy(dst, src, copylen);
		dst[copylen] = 0;
	}
	return result;
}
#endif

static char * name;
static char * sandbox;
static char * filemap, * filemap_end;
static char * depends;	
static int sock=-1;
static int enable_fence=0;
static Tcl_Interp * interp;
static pthread_mutex_t sock_mutex=PTHREAD_MUTEX_INITIALIZER;
static int cleanuping=0;
static char * sdk=
#ifdef TRACE_SDK
	/*"MacOSX10.4u.sdk"*/
	TRACE_SDK
#else
	0
#endif
;

static void send_file_map(int sock);
static void dep_check(int sock, const char * path);
static void sandbox_violation(int sock, const char * path);
static void ui_warn(const char * format, ...);
static void ui_info(const char * format, ...);

#define MAX_SOCKETS ((FD_SETSIZE)-1)

static int TracelibSetNameCmd(Tcl_Interp * interp, int objc, Tcl_Obj *CONST objv[])
{
	if (objc != 3)
	{
		Tcl_WrongNumArgs(interp, 2, objv, "number of arguments should be exactly 3");
		return TCL_ERROR;
	}
	
	name=strdup(Tcl_GetString(objv[2]));
	if (!name) {
	    Tcl_SetResult(interp, "memory allocation failed", TCL_STATIC);
	    return TCL_ERROR;
	}
	
	return TCL_OK;
}

/*
 * Save sandbox path into memory and prepare it for checks.
 * For now it just change : to \0, and add last \0
 * Input:
 *  /dev/null:/dev/tty:/tmp
 * In variable;
 * /dev/null\0/dev/tty\0/tmp\0\0
 */
static int TracelibSetSandboxCmd(Tcl_Interp * interp, int objc, Tcl_Obj *CONST objv[])
{
	int len;
	char * t;
	
	if (objc != 3)
	{
		Tcl_WrongNumArgs(interp, 2, objv, "number of arguments should be exactly 3");
		return TCL_ERROR;
	}
	
	len=strlen(Tcl_GetString(objv[2]))+2;
	sandbox=(char*)malloc(len);
	if (!sandbox) {
	    Tcl_SetResult(interp, "memory allocation failed", TCL_STATIC);
	    return TCL_ERROR;
	}
	memset(sandbox, 0, len);
	strlcpy(sandbox, Tcl_GetString(objv[2]), len);
	for(t=sandbox;(t=strchr(t+1, ':'));)
	{
		/* : -> \0 */
		if(t[-1]!='\\')
			*t=0;
		else
			/* \: -> : */
			/* TODO \\: -> \: */
			memmove(t-1, t, strlen(t));
	}
	
	return TCL_OK;
}

/*
 * Is there more data? (return 1 if more data in socket, 0 otherwise)
 */
static char can_I_recv_more(int sock)
{
	struct timeval tv;
	fd_set fdr;
	tv.tv_sec  = 0;
	tv.tv_usec = 0;

	FD_ZERO(&fdr);
	FD_SET(sock, &fdr);
	return select(sock+1, &fdr, 0, 0, &tv) == 1;
}

/*
 * receive line from socket, parse it and send answer
 */
static char process_line(int sock)
{
	char * t, buf[1024]={0}, *f, *next_t;
	int len;
	
	if((len=recv(sock, buf, sizeof(buf) - 1, 0))==-1)
		return 0;
	if(!len)
		return 0;
	
	buf[len] = '\0';
	
	for(t=buf;*t&&t-buf<(int)sizeof(buf);t=next_t)
	{
		next_t = t+strlen(t)+1;
		if(next_t == buf + sizeof(buf) && len == sizeof(buf) - 1)
		{
			memmove(buf, t, next_t - t);
			t = buf;
			{
				char * end_of_t = t + strlen(t);
				*end_of_t = ' ';
				for(;can_I_recv_more(sock);)
				{
					if(recv(sock, end_of_t, 1, 0) != 1)
					{
						ui_warn("recv failed");
						return 0;
					}
					if(*end_of_t++ == '\0')
						break;
				}
			}
		}
    
		f=strchr(t, '\t');
		if(!f)
		{
			ui_warn("malformed command %s", t);
			break;
		}

		/* Replace \t with \0 */
		*f = '\0';
		/* Advance pointer to arguments */
		f++;

		if(!strcmp(t, "filemap"))
		{
			send_file_map(sock);
		}else if(!strcmp(t, "sandbox_violation"))
		{
			sandbox_violation(sock, f);
		}else if(!strcmp(t, "dep_check"))
		{
			dep_check(sock, f);
		}else if(!strcmp(t, "execve"))
		{
			/* ====================== */
			/* = TODO: do something = */
			/* ====================== */
		}else
		{
			ui_warn("unknown command %s (%s)", t, f);
		}
	}
	return 1;
}

static void send_file_map(int sock)
{
	if(!filemap)
	{
		char * t, * _;
		
		size_t remaining = 1024;
		filemap=(char*)malloc(remaining);
		if (!filemap) {
		    ui_warn("send_file_map: memory allocation failed");
	        return;
		}
		t=filemap;
		
		#define append_allow(path, resolution) do { strlcpy(t, path, remaining); \
		                                            if (remaining < (strlen(t)+3)) \
		                                                remaining=0; \
		                                            else \
		                                                remaining-=strlen(t)+3; \
		                                            t+=strlen(t)+1; \
		                                            *t++=resolution; \
		                                            *t++=0; \
		                                          } while(0);
		if(enable_fence)
		{
			for(_=sandbox; *_; _+=strlen(_)+1)
				append_allow(_, 0);
			
			append_allow("/bin", 0);
			append_allow("/sbin", 0);
			append_allow("/dev", 0);
			append_allow(Tcl_GetVar(interp, "prefix", TCL_GLOBAL_ONLY), 2);
			/* If there is no SDK we will allow everything in /usr /System/Library etc, else add binaries to allow, and redirect root to SDK. */
			if(sdk&&*sdk)
			{
				char buf[260];
				buf[0] = '\0';
				strlcat(buf, Tcl_GetVar(interp, "developer_dir", TCL_GLOBAL_ONLY), 260);
				strlcat(buf, "/SDKs/", 260);
				strlcat(buf, sdk, 260);
			
				append_allow("/usr/bin", 0);
				append_allow("/usr/sbin", 0);
				append_allow("/usr/libexec/gcc", 0);
				append_allow("/System/Library/Perl", 0);
				append_allow("/", 1);
				strlcpy(t-1, buf, remaining);
				t+=strlen(t)+1;
			}else
			{
				append_allow("/usr", 0);
				append_allow("/System/Library", 0);
				append_allow("/Library", 0);
				append_allow(Tcl_GetVar(interp, "developer_dir", TCL_GLOBAL_ONLY), 0);
			}
		}else
			append_allow("/", 0);
		filemap_end=t;
		#undef append_allow
	}
	
	{
		size_t s=filemap_end-filemap;
		send(sock, &s, sizeof(s), 0);
		send(sock, filemap, s, 0);
	}
}

static void sandbox_violation(int sock UNUSED, const char * path)
{
	Tcl_SetVar(interp, "path", path, 0);
	Tcl_Eval(interp, "slave_add_sandbox_violation $path");
	Tcl_UnsetVar(interp, "path", 0);
}

static void dep_check(int sock, const char * path)
{
	char * port=0;
	size_t len=1;
	char resolution='!';
		
	Tcl_SetVar(interp, "path", path, 0);
	Tcl_Eval(interp, "registry::file_registered $path");
	port=strdup(Tcl_GetStringResult(interp));
	if (!port) {
		ui_warn("dep_check: memory allocation failed");
	    return;
	}
	Tcl_UnsetVar(interp, "path", 0);
	
	if(*port!='0'||port[1])
	{
		char * t;
	
		t=depends;
		for(;*t;t+=strlen(t)+1)
		{
			if(!strcmp(t, port))
			{
				resolution='+';
				break;
			}
		}
	}
	
	if(resolution!='+') {
	    if(*port=='0'&&!port[1])
		    ui_info("trace: access denied to %s (*unknown*)", path);
		else
		    ui_info("trace: access denied to %s (%s)", path, port);
    }

	free(port);
	
	if(send(sock, &len, sizeof(len), 0)==-1)
		ui_warn("tracelib send failed");
	if(send(sock, &resolution, 1, 0)==-1)
		ui_warn("tracelib send failed");
}

static void ui_msg(const char * severity, const char * format, va_list va)
{
	char buf[1024], tclcmd[32];
	
	vsnprintf(buf, sizeof(buf), format, va);
	
	snprintf(tclcmd, sizeof(tclcmd), "ui_%s $warn", severity);
	
	Tcl_SetVar(interp, "warn", buf, 0);
	
	Tcl_Eval(interp, tclcmd);
	Tcl_UnsetVar(interp, "warn", 0);
	
}

static void ui_warn(const char * format, ...)
{
	va_list va;
	
	va_start(va, format);
		ui_msg("warn", format, va);
	va_end(va);
}

static void ui_info(const char * format, ...)
{
	va_list va;
	
	va_start(va, format);
		ui_msg("msg", format, va);
	va_end(va);
}

static int TracelibOpenSocketCmd(Tcl_Interp * in)
{
	struct sockaddr_un sun;
	struct rlimit rl;
	
	pthread_mutex_lock(&sock_mutex);
	if(cleanuping)
	{
		pthread_mutex_unlock(&sock_mutex);
		return 0;
	}
	sock=socket(AF_UNIX, SOCK_STREAM, 0);
	if (sock == -1) {
		Tcl_SetErrno(errno);
		Tcl_ResetResult(interp);
		Tcl_AppendResult(interp, "socket: ", (char *) Tcl_PosixError(interp), NULL);
		pthread_mutex_unlock(&sock_mutex);
		return TCL_ERROR;
	}
	pthread_mutex_unlock(&sock_mutex);
	
	interp=in;
	
	rl.rlim_cur=rl.rlim_max=RLIM_INFINITY;
#if defined(__APPLE__) && defined(OPEN_MAX)
	if (OPEN_MAX < rl.rlim_cur)
		rl.rlim_cur = OPEN_MAX;
#endif
	if(setrlimit(RLIMIT_NOFILE, &rl)==-1)
	{
		ui_warn("setrlimit failed (%d)", errno);
	}

	
	sun.sun_family=AF_UNIX;
	strlcpy(sun.sun_path, name, sizeof(sun.sun_path));
	if (bind(sock, (struct sockaddr*)&sun, sizeof(sun)) == -1) {
		Tcl_SetErrno(errno);
		Tcl_ResetResult(interp);
		Tcl_AppendResult(interp, "bind: ", (char *) Tcl_PosixError(interp), NULL);
		return TCL_ERROR;
	}
	
	if (listen(sock, 5) == -1) {
		Tcl_SetErrno(errno);
		Tcl_ResetResult(interp);
		Tcl_AppendResult(interp, "listen: ", (char *) Tcl_PosixError(interp), NULL);
		return TCL_ERROR;
	}

        return TCL_OK;
}


static int TracelibRunCmd(Tcl_Interp * in UNUSED)
{
	int max_fd, max_used, socks[MAX_SOCKETS];
	fd_set fdr;
	int i;

	max_used=0;
	max_fd=sock;
	
	for(;sock!=-1&&!cleanuping;)
	{
		FD_ZERO(&fdr);
		FD_SET(sock, &fdr);
		for(i=0;i<max_used;++i)
			FD_SET(socks[i], &fdr);
				
		if(select(max_fd+1, &fdr, 0, 0, 0)<1)
		{
			continue;
		}
		if(sock==-1)
		{
			break;
		}
		if(FD_ISSET(sock, &fdr))
		{
			int s;
			s=accept(sock, 0, 0);
			
			if(s==-1)
			{
				if(cleanuping)
					break;
				else
					ui_warn("tracelib: accept return -1 (errno: %d)", errno);
				/* failed sometimes and i dunno why*/
				continue;
			}
			/* Temporary solution, it's better to regenerate this variable in each iteration, because when closing socket we'll get it too high */				
			if(s>max_fd)
				max_fd=s;
			for(i=0;i<max_used;++i)
				if(!socks[i])
				{
					socks[i]=s;
					break;
				}
			if(i==max_used)
			{
				if(max_used==MAX_SOCKETS-1)
				{
					ui_warn("There is no place to store socket");
					close(s);
				}
				else
					socks[max_used++]=s;
			}
		}
		
		for(i=0;i<max_used;++i)
		{
			if(!socks[i])
				continue;
			if(FD_ISSET(socks[i], &fdr))
			{
				if(!process_line(socks[i]))
				{
					close(socks[i]);
					socks[i]=0;
					continue;
				}
			}
		}
	}
	
	for(i=0;i<max_used;++i)
	{
		if(socks[i])
		{
			close(socks[i]);
			socks[i]=0;
		}
	}
	
	return TCL_OK;
}

static int TracelibCleanCmd(Tcl_Interp * interp UNUSED)
{
	#define safe_free(x) do{free(x); x=0;}while(0);
	cleanuping=1;
	pthread_mutex_lock(&sock_mutex);
	if(sock!=-1)
	{
		/* shutdown(sock, SHUT_RDWR);*/
		close(sock);
		sock=-1;
	}
	pthread_mutex_unlock(&sock_mutex);
	if(name)
	{
		unlink(name);
		safe_free(name);
	}
	if(filemap)
		safe_free(filemap);
	if(depends)
		safe_free(depends);
	enable_fence=0;
	#undef safe_free
	cleanuping=0;
	return TCL_OK;
}

static int TracelibCloseSocketCmd(Tcl_Interp * interp UNUSED)
{
	cleanuping=1;
	pthread_mutex_lock(&sock_mutex);
	if(sock!=-1)
	{
		/*shutdown(sock, SHUT_RDWR);*/
		close(sock);
		sock=-1;
	}
	pthread_mutex_unlock(&sock_mutex);
	return TCL_OK;
}

static int TracelibSetDeps(Tcl_Interp * interp UNUSED, int objc, Tcl_Obj* CONST objv[])
{
	char * t, * d;
	size_t l;
	if(objc!=3)
	{
		Tcl_WrongNumArgs(interp, 2, objv, "number of arguments should be exactly 3");
		return TCL_ERROR;
	}
	
	d=Tcl_GetString(objv[2]);
	l=strlen(d);
	depends=malloc(l+2);
	if (!depends) {
	    Tcl_SetResult(interp, "memory allocation failed", TCL_STATIC);
	    return TCL_ERROR;
	}
	depends[l+1]=0;
	strlcpy(depends, d, l+2);
	for(t=depends;*t;++t)
		if(*t==' ')
			*t++=0;
	
	return TCL_OK;
}

static int TracelibEnableFence(Tcl_Interp * interp UNUSED)
{
	enable_fence=1;
	if(filemap)
		free(filemap);
	filemap=0;
	return TCL_OK;
}

int TracelibCmd(ClientData clientData UNUSED, Tcl_Interp* interp, int objc, Tcl_Obj* CONST objv[])
{
	int result=TCL_OK;
	static const char * options[]={"setname", "opensocket", "run", "clean", "setsandbox", "closesocket", "setdeps", "enablefence", 0};
	typedef enum 
	{
		kSetName,
		kOpenSocket,
		kRun,
		kClean,
		kSetSandbox,
		kCloseSocket,
		kSetDeps,
		kEnableFence
	} EOptions;
	EOptions current_option;
	
	/* There is no args for commands now. */
	if (objc <2)
	{
		Tcl_WrongNumArgs(interp, 1, objv, "option");
		return TCL_ERROR;
	}
	
	result=Tcl_GetIndexFromObj(interp, objv[1], options, "option", 0, (int*)&current_option);
	if(result==TCL_OK)
	{
		switch(current_option)
		{
		case kSetName:
			result=TracelibSetNameCmd(interp, objc, objv);
			break;
		case kOpenSocket:
			result=TracelibOpenSocketCmd(interp);
			break;
		case kRun:
			result=TracelibRunCmd(interp);
			break;
		case kClean:
			result=TracelibCleanCmd(interp);
			break;
		case kCloseSocket:
			result=TracelibCloseSocketCmd(interp);
			break;
		case kSetSandbox:
			result=TracelibSetSandboxCmd(interp, objc, objv);
			break;
		case kSetDeps:
			result=TracelibSetDeps(interp, objc, objv);
			break;
		case kEnableFence:
			result=TracelibEnableFence(interp);
			break;
		}
	}
	
	return result;
}