#!/bin/bash
#
# This shell-script genereates the fl_wrapper.c source file.

cat << EOT
/* ROCK Linux Wrapper for getting a list of created files
 *
 * --- ROCK-COPYRIGHT-NOTE-BEGIN ---
 * 
 * This copyright note is auto-generated by ./scripts/Create-CopyPatch.
 * Please add additional copyright information _after_ the line containing
 * the ROCK-COPYRIGHT-NOTE-END tag. Otherwise it might get removed by
 * the ./scripts/Create-CopyPatch script. Do not edit this copyright text!
 * 
 * ROCK Linux: rock-src/misc/tools-source/fl_wrapper.c.sh
 * ROCK Linux is Copyright (C) 1998 - 2006 Clifford Wolf
 * 
 * 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; either version 2 of the License, or
 * (at your option) any later version. A copy of the GNU General Public
 * License can be found at Documentation/COPYING.
 * 
 * Many people helped and are helping developing ROCK Linux. Please
 * have a look at https://www.rocklinux.org/ and the Documentation/TEAM
 * file for details.
 * 
 * --- ROCK-COPYRIGHT-NOTE-END ---
 *
 * Copyright (C) 2004-2005 The T2 SDE Project
 *
 * gcc -Wall -O2 -ldl -shared -o fl_wrapper.so fl_wrapper.c
 *
 * !!! THIS FILE IS AUTO-GENERATED BY $0 !!!
 *
 * ELF Dynamic Loading Documentation:
 *  - https://www.linuxdoc.org/HOWTO/GCC-HOWTO-7.html
 *  - https://www.educ.umu.se/~bjorn/mhonarc-files/linux-gcc/msg00576.html
 *  - /usr/include/dlfcn.h
 */


/* Headers and prototypes */

#define DEBUG 0
#define DLOPEN_LIBC 1

#define _GNU_SOURCE
#define _REENTRANT

#define open   xxx_open
#define open64 xxx_open64
#define mknod  xxx_mknod

#define _LARGEFILE_SOURCE
#define _LARGEFILE64_SOURCE

#  include <dlfcn.h>
#  include <errno.h>
#  include <fcntl.h>
#  include <stdio.h>
#  include <stdlib.h>
#  include <string.h>
#  include <sys/stat.h>
#  include <sys/types.h>
#  include <unistd.h>
#  include <utime.h>
#  include <stdarg.h>

#undef _LARGEFILE64_SOURCE
#undef _LARGEFILE_SOURCE

#undef mknod
#undef open
#undef open64

static void * get_dl_symbol(char *);

struct status_t {
	ino_t   inode;
	off_t   size;
	time_t  mtime;
	time_t  ctime;
};

static void handle_file_access_before(const char *, const char *, struct status_t *);
static void handle_file_access_after(const char *, const char *, struct status_t *);

char *wlog = 0, *rlog = 0, *cmdname = "unkown";

/* Wrapper Functions */
EOT

# This has been made with cpp-macros before until they turned to be absolutely
# unreadable ...
#
add_wrapper()
{
	line="$( echo "$*" | sed 's/ *, */,/g' )"
	old_ifs="$IFS" ; IFS="," ; set $line ; IFS="$old_ifs"

	ret_type=$1 ; shift ; function=$1 ; shift
	p1="" ; p2="" ; for x ; do p1="$p1$x, " ; done
	for x ; do x="${x%%\[\]}" ; p2="$p2${x##* }, " ; done
	p1="${p1%, }" ; p2="${p2%, }"

	if [ "${function#exec}" = "${function}" ]
	then
		echo ; cat << EOT
extern $ret_type $function($p1);
$ret_type (*orig_$function)($p1) = 0;

$ret_type $function($p1)
{
	struct status_t status;
	int old_errno=errno;
	$ret_type rc;

	handle_file_access_before("$function", f, &status);
	if (!orig_$function) orig_$function = get_dl_symbol("$function");
	errno=old_errno;

#if DEBUG == 1
	fprintf(stderr, "fl_wrapper.so debug [%d]: going to run original $function() at %p (wrapper is at %p).\n",
		getpid(), orig_$function, $function);
#endif
	rc = orig_$function($p2);

	old_errno=errno;
	handle_file_access_after("$function", f, &status);
	errno=old_errno;

	return rc;
}
EOT
	else
		echo ; cat << EOT
extern $ret_type $function($p1);
$ret_type (*orig_$function)($p1) = 0;

$ret_type $function($p1)
{
	int old_errno=errno;

	handle_file_access_after("$function", f, 0);
	if (!orig_$function) orig_$function = get_dl_symbol("$function");
	errno=old_errno;

	return orig_$function($p2);
}
EOT
	fi
}

add_wrapper 'FILE*, fopen,   const char* f, const char* g'
add_wrapper 'FILE*, fopen64, const char* f, const char* g'

add_wrapper 'int,   creat,   const char* f, mode_t m'
add_wrapper 'int,   creat64, const char* f, mode_t m'

add_wrapper 'int,   mkdir,   const char* f, mode_t m'
add_wrapper 'int,   mknod,   const char* f, mode_t m, dev_t d'

add_wrapper 'int,   link,    const char* s, const char* f'
add_wrapper 'int,   symlink, const char* s, const char* f'
add_wrapper 'int,   rename,  const char* s, const char* f'

add_wrapper 'int,   utime,   const char* f, const struct utimbuf* t'
add_wrapper 'int,   utimes,  const char* f, struct timeval* t'

add_wrapper 'int,   execv,   const char* f, char* const a[]'
add_wrapper 'int,   execve,  const char* f, char* const a[], char* const e[]'

echo
cat fl_wrapper_execl.c
cat fl_wrapper_open.c

echo ; cat << "EOT"
/* Internal Functions */

static void * get_dl_symbol(char * symname)
{
	void * rc;
#if DLOPEN_LIBC
	static void * libc_handle = 0;

	if (!libc_handle) libc_handle=dlopen("libc.so.6", RTLD_LAZY);
	if (!libc_handle) {
		printf("fl_wrapper.so: Can't dlopen libc: %s\n", dlerror());
		abort();
	}

        rc = dlsym(libc_handle, symname);
#  if DEBUG == 1
	fprintf(stderr, "fl_wrapper.so debug [%d]: Symbol '%s' in libc (%p) has been resolved to %p.\n",
		getpid(), symname, libc_handle, rc);
#  endif
#else
        rc = dlsym(RTLD_NEXT, symname);
#  if DEBUG == 1
	fprintf(stderr, "fl_wrapper.so debug [%d]: Symbol '%s' (RTLD_NEXT) has been resolved to %p.\n",
		getpid(), symname, rc);
#  endif
#endif
	if (!rc) {
		printf("fl_wrapper.so: Can't resolve %s: %s\n",
		       symname, dlerror());
		abort();
	}

        return rc;
}

static int pid2ppid(int pid)
{
	char buffer[100];
	int fd, rc, ppid = 0;

	sprintf(buffer, "/proc/%d/stat", pid);
	if ( (fd = open(buffer, O_RDONLY, 0)) < 0 ) return 0;
	if ( (rc = read(fd, buffer, 99)) > 0) {
		buffer[rc] = 0;
		/* format: 27910 (bash) S 27315 ... */
		sscanf(buffer, "%*[^ ] %*[^ ] %*[^ ] %d", &ppid);
	}
	close(fd);

	return ppid;
}

/* this is only called from fl_wrapper_init(). so it doesn't need to be
 * reentrant. */
static char *getpname(int pid)
{
	static char p[512];
	char buffer[513]="";
	char *arg=0, *b;
	int i, fd, rc;

	sprintf(buffer, "/proc/%d/cmdline", pid);
	if ( (fd = open(buffer, O_RDONLY, 0)) < 0 ) return "unkown";
	if ( (rc = read(fd, buffer, 512)) > 0) {
		buffer[rc--] = 0;
		for (i=0; i<rc; i++)
			if (buffer[i] == 0 && buffer[i+1] != '-')
				{ arg = buffer+i+1; break; }
	}
	close(fd);

	b = basename(buffer);
	snprintf(p, 512, "%s", b);

	if ( !strcmp(b, "bash") || !strcmp(b, "sh") ||
	     !strcmp(b, "perl") || !strcmp(b, "python") )
		if ( arg && *arg &&
		     strlen(arg) < 100 && !strchr(arg, '\n') &&
		     !strchr(arg, ' ') && !strchr(arg, ';') )
			snprintf(p, 512, "%s(%s)", b, basename(arg));

	return p;
}

/* invert the order by recursion. there will be only one recursion tree
 * so we can use a static var for managing the last ent */
static void addptree(int *txtpos, char *cmdtxt, int pid, int basepid)
{
	static char l[512] = "";
	char *p;

	if (!pid || pid == basepid) return;

	addptree(txtpos, cmdtxt, pid2ppid(pid), basepid);

	p = getpname(pid);

	if (*txtpos < 4000)
		if ( strcmp(l, p) )
			*txtpos += snprintf(cmdtxt+*txtpos, 4096-*txtpos, "%s%s",
					*txtpos ? "." : "", getpname(pid));
		else
			*txtpos += snprintf(cmdtxt+*txtpos, 4096-*txtpos, "*");

	strcpy(l, p);
}

void __attribute__ ((constructor)) fl_wrapper_init()
{
	char cmdtxt[4096] = "";
	char *basepid_txt = getenv("FLWRAPPER_BASEPID");
	int basepid = 0, txtpos=0;

	if (basepid_txt)
		basepid = atoi(basepid_txt);

	addptree(&txtpos, cmdtxt, getpid(), basepid);
	cmdname = strdup(cmdtxt);

	wlog = getenv("FLWRAPPER_WLOG");
	rlog = getenv("FLWRAPPER_RLOG");
}

static void handle_file_access_before(const char * func, const char * file,
                               struct status_t * status)
{
	struct stat st;
#if DEBUG == 1
	fprintf(stderr, "fl_wrapper.so debug [%d]: begin of handle_file_access_before(\"%s\", \"%s\", xxx)\n",
		getpid(), func, file);
#endif
	if ( lstat(file,&st) ) {
		status->inode=0;  status->size=0;
		status->mtime=0;  status->ctime=0;
	} else {
		status->inode=st.st_ino;    status->size=st.st_size;
		status->mtime=st.st_mtime;  status->ctime=st.st_ctime;
	}
#if DEBUG == 1
	fprintf(stderr, "fl_wrapper.so debug [%d]: end   of handle_file_access_before(\"%s\", \"%s\", xxx)\n",
		getpid(), func, file);
#endif
}

static void handle_file_access_after(const char * func, const char * file,
                              struct status_t * status)
{
	char buf[512], *buf2, *logfile;
	int fd; struct stat st;

#if DEBUG == 1
	fprintf(stderr, "fl_wrapper.so debug [%d]: begin of handle_file_access_after(\"%s\", \"%s\", xxx)\n",
		getpid(), func, file);
#endif
	if ( wlog != 0 && !strcmp(file, wlog) ) return;
	if ( rlog != 0 && !strcmp(file, rlog) ) return;
	if ( lstat(file, &st) ) return;

	if ( (status != 0) && (status->inode != st.st_ino ||
	     status->size  != st.st_size || status->mtime != st.st_mtime ||
	     status->ctime != st.st_ctime) ) { logfile = wlog; }
	else { logfile = rlog; }

	if ( logfile == 0 ) return;
#ifdef __USE_LARGEFILE
	fd=open64(logfile,O_APPEND|O_WRONLY|O_LARGEFILE,0);
#else
#warning "The wrapper library will not work properly for large logs!"
	fd=open(logfile,O_APPEND|O_WRONLY,0);
#endif
	if (fd == -1) return;

	if (file[0] == '/') {
		sprintf(buf,"%s.%s:\t%s\n",
		        cmdname, func, file);
	} else {
		buf2=get_current_dir_name();
		sprintf(buf,"%s.%s:\t%s%s%s\n",
			cmdname, func, buf2,
			strcmp(buf2,"/") ? "/" : "", file);
		free(buf2);
	}
	write(fd,buf,strlen(buf));
	close(fd);
#if DEBUG == 1
	fprintf(stderr, "fl_wrapper.so debug [%d]: end   of handle_file_access_after(\"%s\", \"%s\", xxx)\n",
		getpid(), func, file);
#endif
}
EOT