clamav/libclamav/others_common.c

/*
 *  Copyright (C) 2007-2008 Sourcefire, Inc.
 *
 *  Authors: Tomasz Kojm, Trog
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License version 2 as
 *  published by the Free Software Foundation.
 *
 *  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., 51 Franklin Street, Fifth Floor, Boston,
 *  MA 02110-1301, USA.
 *
 */

#if HAVE_CONFIG_H
#include "clamav-config.h"
#endif

#include <stdio.h>
#include <stdarg.h>
#include <string.h>
#include <stdlib.h>
#include <ctype.h>
#ifdef	HAVE_UNISTD_H
#include <unistd.h>
#endif
#include <sys/types.h>
#include <sys/stat.h>
#include <dirent.h>
#ifndef	_WIN32
#include <sys/wait.h>
#include <sys/time.h>
#endif
#include <time.h>
#include <fcntl.h>
#ifdef	HAVE_PWD_H
#include <pwd.h>
#endif
#include <errno.h>
#include "target.h"
#ifdef	HAVE_SYS_PARAM_H
#include <sys/param.h>
#endif
#ifdef	HAVE_MALLOC_H
#include <malloc.h>
#endif

#include "clamav.h"
#include "others.h"
#include "md5.h"
#include "cltypes.h"
#include "regex/regex.h"
#include "ltdl.h"
#include "matcher-ac.h"
#include "md5.h"

static unsigned char name_salt[16] = { 16, 38, 97, 12, 8, 4, 72, 196, 217, 144, 33, 124, 18, 11, 17, 253 };

#ifdef CL_NOTHREADS
#undef CL_THREAD_SAFE
#endif

#ifdef CL_THREAD_SAFE
#  include <pthread.h>

static pthread_mutex_t cli_gentemp_mutex = PTHREAD_MUTEX_INITIALIZER;
# ifndef HAVE_CTIME_R
static pthread_mutex_t cli_ctime_mutex = PTHREAD_MUTEX_INITIALIZER;
# endif
static pthread_mutex_t cli_strerror_mutex = PTHREAD_MUTEX_INITIALIZER;
static pthread_key_t cli_ctx_tls_key;
static pthread_once_t cli_ctx_tls_key_once = PTHREAD_ONCE_INIT;

static void cli_ctx_tls_key_alloc(void)
{
    pthread_key_create(&cli_ctx_tls_key, NULL);
}

void cli_logg_setup(const cli_ctx *ctx)
{
    pthread_once(&cli_ctx_tls_key_once, cli_ctx_tls_key_alloc);
    pthread_setspecific(cli_ctx_tls_key, ctx);
}

void cli_logg_unsetup(void)
{
    pthread_setspecific(cli_ctx_tls_key, NULL);
}

static inline void *cli_getctx(void)
{
    cli_ctx *ctx = pthread_getspecific(cli_ctx_tls_key);
    return ctx ? ctx->cb_ctx : NULL;
}
#else

static const cli_ctx *current_ctx = NULL;
void cli_logg_setup(const cli_ctx *ctx)
{
    current_ctx = ctx;
}

static inline void *cli_getctx(void)
{
    return current_ctx ? current_ctx->cb_ctx : NULL;
}
#endif
uint8_t cli_debug_flag = 0;

static void fputs_callback(enum cl_msg severity, const char *fullmsg, const char *msg, void *context)
{
    fputs(fullmsg, stderr);
}

static clcb_msg msg_callback = fputs_callback;

void cl_set_clcb_msg(clcb_msg callback)
{
    msg_callback = callback;
}

#define MSGCODE(buff, len, x)				    \
	va_list args;					    \
	int len = sizeof(x) - 1;			    \
	char buff[BUFSIZ];				    \
    strncpy(buff, x, len);				    \
    va_start(args, str);				    \
    vsnprintf(buff + len, sizeof(buff) - len, str, args);   \
    buff[sizeof(buff) - 1] = '\0';			    \
    va_end(args)

void cli_warnmsg(const char *str, ...)
{
    MSGCODE(buff, len, "LibClamAV Warning: ");
    msg_callback(CL_MSG_WARN, buff, buff+len, cli_getctx());
}

void cli_errmsg(const char *str, ...)
{
    MSGCODE(buff, len, "LibClamAV Error: ");
    msg_callback(CL_MSG_ERROR, buff, buff+len, cli_getctx());
}

void cli_infomsg(const cli_ctx* ctx, const char *str, ...)
{
    MSGCODE(buff, len, "LibClamAV info: ");
    msg_callback(CL_MSG_INFO_VERBOSE, buff, buff+len, ctx ? ctx->cb_ctx : NULL);
}

void cli_dbgmsg_internal(const char *str, ...)
{
    MSGCODE(buff, len, "LibClamAV debug: ");
    fputs(buff, stderr);
}

int cli_matchregex(const char *str, const char *regex)
{
	regex_t reg;
	int match, flags = REG_EXTENDED | REG_NOSUB;
#ifdef _WIN32
    flags |= REG_ICASE;
#endif
    if(cli_regcomp(&reg, regex, flags) == 0) {
	match = (cli_regexec(&reg, str, 0, NULL, 0) == REG_NOMATCH) ? 0 : 1;
	cli_regfree(&reg);
	return match;
    }

    return 0;
}
void *cli_malloc(size_t size)
{
	void *alloc;


    if(!size || size > CLI_MAX_ALLOCATION) {
	cli_errmsg("cli_malloc(): Attempt to allocate %lu bytes. Please report to http://bugs.clamav.net\n", (unsigned long int) size);
	return NULL;
    }

    alloc = malloc(size);

    if(!alloc) {
	cli_errmsg("cli_malloc(): Can't allocate memory (%lu bytes).\n", (unsigned long int) size);
	perror("malloc_problem");
	return NULL;
    } else return alloc;
}

void *cli_calloc(size_t nmemb, size_t size)
{
	void *alloc;


    if(!nmemb || !size || size > CLI_MAX_ALLOCATION || nmemb > CLI_MAX_ALLOCATION
        || (nmemb*size > CLI_MAX_ALLOCATION)) {
	cli_errmsg("cli_calloc(): Attempt to allocate %lu bytes. Please report to http://bugs.clamav.net\n", (unsigned long int) nmemb*size);
	return NULL;
    }

    alloc = calloc(nmemb, size);

    if(!alloc) {
	cli_errmsg("cli_calloc(): Can't allocate memory (%lu bytes).\n", (unsigned long int) (nmemb * size));
	perror("calloc_problem");
	return NULL;
    } else return alloc;
}

void *cli_realloc(void *ptr, size_t size)
{
	void *alloc;


    if(!size || size > CLI_MAX_ALLOCATION) {
	cli_errmsg("cli_realloc(): Attempt to allocate %lu bytes. Please report to http://bugs.clamav.net\n", (unsigned long int) size);
	return NULL;
    }

    alloc = realloc(ptr, size);

    if(!alloc) {
	cli_errmsg("cli_realloc(): Can't re-allocate memory to %lu bytes.\n", (unsigned long int) size);
	perror("realloc_problem");
	return NULL;
    } else return alloc;
}

void *cli_realloc2(void *ptr, size_t size)
{
	void *alloc;


    if(!size || size > CLI_MAX_ALLOCATION) {
	cli_errmsg("cli_realloc2(): Attempt to allocate %lu bytes. Please report to http://bugs.clamav.net\n", (unsigned long int) size);
	return NULL;
    }

    alloc = realloc(ptr, size);

    if(!alloc) {
	cli_errmsg("cli_realloc2(): Can't re-allocate memory to %lu bytes.\n", (unsigned long int) size);
	perror("realloc_problem");
	if(ptr)
	    free(ptr);
	return NULL;
    } else return alloc;
}

char *cli_strdup(const char *s)
{
        char *alloc;


    if(s == NULL) {
        cli_errmsg("cli_strdup(): s == NULL. Please report to http://bugs.clamav.net\n");
        return NULL;
    }

    alloc = strdup(s);

    if(!alloc) {
        cli_errmsg("cli_strdup(): Can't allocate memory (%u bytes).\n", (unsigned int) strlen(s));
        perror("strdup_problem");
        return NULL;
    }

    return alloc;
}

/* returns converted timestamp, in case of error the returned string contains at least one character */
const char* cli_ctime(const time_t *timep, char *buf, const size_t bufsize)
{
	const char *ret;
	if(bufsize < 26) {
		/* standard says we must have at least 26 bytes buffer */
		cli_warnmsg("buffer too small for ctime\n");
		return " ";
	}
	if((uint32_t)(*timep) > 0x7fffffff) {
		/* some systems can consider these timestamps invalid */
		strncpy(buf, "invalid timestamp", bufsize-1);
		buf[bufsize-1] = '\0';
		return buf;
	}

#ifdef HAVE_CTIME_R	
# ifdef HAVE_CTIME_R_2
	ret = ctime_r(timep, buf);
# else
	ret = ctime_r(timep, buf, bufsize);
# endif
#else /* no ctime_r */

# ifdef CL_THREAD_SAFE
	pthread_mutex_lock(&cli_ctime_mutex);
# endif
	ret = ctime(timep);
	if(ret) {
		strncpy(buf, ret, bufsize-1);
		buf[bufsize-1] = '\0';
		ret = buf;
	}
# ifdef CL_THREAD_SAFE
	pthread_mutex_unlock(&cli_ctime_mutex);
# endif
#endif
	/* common */
	if(!ret) {
		buf[0] = ' ';
		buf[1] = '\0';
		return buf;
	}
	return ret;
}

/* Function: readn
        Try hard to read the requested number of bytes
*/
int cli_readn(int fd, void *buff, unsigned int count)
{
        int retval;
        unsigned int todo;
        unsigned char *current;


        todo = count;
        current = (unsigned char *) buff;

        do {
                retval = read(fd, current, todo);
                if (retval == 0) {
                        return (count - todo);
                }
                if (retval < 0) {
			char err[128];
			if (errno == EINTR) {
				continue;
			}
			cli_errmsg("cli_readn: read error: %s\n", cli_strerror(errno, err, sizeof(err)));
                        return -1;
                }
                todo -= retval;
                current += retval;
        } while (todo > 0);


        return count;
}

/* Function: writen
        Try hard to write the specified number of bytes
*/
int cli_writen(int fd, const void *buff, unsigned int count)
{
        int retval;
        unsigned int todo;
        const unsigned char *current;


        todo = count;
        current = (const unsigned char *) buff;

        do {
                retval = write(fd, current, todo);
                if (retval < 0) {
			char err[128];
			if (errno == EINTR) {
				continue;
			}
			cli_errmsg("cli_writen: write error: %s\n", cli_strerror(errno, err, sizeof(err)));
                        return -1;
                }
                todo -= retval;
                current += retval;
        } while (todo > 0);


        return count;
}

int cli_filecopy(const char *src, const char *dest)
{

#ifdef _WIN32
    return !CopyFileA(src, dest, 0) ? 0 : -1;
#else
	char *buffer;
	int s, d, bytes;


    if((s = open(src, O_RDONLY|O_BINARY)) == -1)
	return -1;

    if((d = open(dest, O_CREAT|O_WRONLY|O_TRUNC|O_BINARY, S_IRWXU)) == -1) {
	close(s);
	return -1;
    }

    if(!(buffer = cli_malloc(FILEBUFF))) {
	close(s);
	close(d);
	return -1;
    }

    while((bytes = cli_readn(s, buffer, FILEBUFF)) > 0)
	cli_writen(d, buffer, bytes);

    free(buffer);
    close(s);

    return close(d);
#endif
}

#ifndef P_tmpdir
#ifdef _WIN32
#define P_tmpdir "C:\\"
#else
#define P_tmpdir "/tmp"
#endif /* _WIN32 */
#endif /* P_tmpdir */

const char *cli_gettmpdir(void) {
	const char *tmpdir;
    if(
#ifdef _WIN32
	!(tmpdir = getenv("TEMP")) && !(tmpdir = getenv("TMP"))
#else
	!(tmpdir = getenv("TMPDIR"))
#endif
    ) tmpdir = P_tmpdir;
    return tmpdir;
}

struct dirent_data {
    char *filename;
    const char *dirname;
    struct stat *statbuf;
    long  ino; /* -1: inode not available */
    int   is_dir;/* 0 - no, 1 - yes */
};

/* sort files before directories, and lower inodes before higher inodes */
static int ftw_compare(const void *a, const void *b)
{
    const struct dirent_data *da = a;
    const struct dirent_data *db = b;
    long diff = da->is_dir - db->is_dir;
    if (!diff) {
	diff = da->ino - db->ino;
    }
    return diff;
}

enum filetype {
    ft_unknown,
    ft_link,
    ft_directory,
    ft_regular,
    ft_skipped_special,
    ft_skipped_link
};

static inline int ft_skipped(enum filetype ft)
{
    return ft != ft_regular && ft != ft_directory;
}

#define FOLLOW_SYMLINK_MASK (CLI_FTW_FOLLOW_FILE_SYMLINK | CLI_FTW_FOLLOW_DIR_SYMLINK)
static int get_filetype(const char *fname, int flags, int need_stat,
			 struct stat *statbuf, enum filetype *ft)
{
    int stated = 0;

    if (*ft == ft_unknown || *ft == ft_link) {
	need_stat = 1;

	if ((flags & FOLLOW_SYMLINK_MASK) != FOLLOW_SYMLINK_MASK) {
	    /* Following only one of directory/file symlinks, or none, may
	     * need to lstat.
	     * If we're following both file and directory symlinks, we don't need
	     * to lstat(), we can just stat() directly.*/
	    if (*ft != ft_link) {
		/* need to lstat to determine if it is a symlink */
		if (lstat(fname, statbuf) == -1)
		    return -1;
		if (S_ISLNK(statbuf->st_mode)) {
		    *ft = ft_link;
		} else {
		    /* It was not a symlink, stat() not needed */
		    need_stat = 0;
		    stated = 1;
		}
	    }
	    if (*ft == ft_link && !(flags & FOLLOW_SYMLINK_MASK)) {
		/* This is a symlink, but we don't follow any symlinks */
		*ft = ft_skipped_link;
		return 0;
	    }
	}
    }

    if (need_stat) {
	if (stat(fname, statbuf) == -1)
	    return -1;
	stated = 1;
    }

    if (*ft == ft_unknown || *ft == ft_link) {
	if (S_ISDIR(statbuf->st_mode) &&
	    (*ft != ft_link || (flags & CLI_FTW_FOLLOW_DIR_SYMLINK))) {
	    /* A directory, or (a symlink to a directory and we're following dir
	     * symlinks) */
	    *ft = ft_directory;
	} else if (S_ISREG(statbuf->st_mode) &&
		   (*ft != ft_link || (flags & CLI_FTW_FOLLOW_FILE_SYMLINK))) {
	    /* A file, or (a symlink to a file and we're following file symlinks) */
	    *ft = ft_regular;
	} else {
	    /* default: skipped */
	    *ft = S_ISLNK(statbuf->st_mode) ?
		ft_skipped_link : ft_skipped_special;
	}
    }
    return stated;
}

static int handle_filetype(const char *fname, int flags,
			   struct stat *statbuf, int *stated, enum filetype *ft,
			   cli_ftw_cb callback, struct cli_ftw_cbdata *data)
{
    int ret;

    *stated = get_filetype(fname, flags, flags & CLI_FTW_NEED_STAT , statbuf, ft);

    if (*stated == -1) {
	/*  we failed a stat() or lstat() */
	ret = callback(NULL, NULL, fname, error_stat, data);
	if (ret != CL_SUCCESS)
	    return ret;
	*ft = ft_unknown;
    } else if (*ft == ft_skipped_link || *ft == ft_skipped_special) {
	/* skipped filetype */
	ret = callback(stated ? statbuf : NULL, NULL, fname,
		       *ft == ft_skipped_link ?
		       warning_skipped_link : warning_skipped_special, data);
	if (ret != CL_SUCCESS)
	    return ret;
    }
    return CL_SUCCESS;
}

static int cli_ftw_dir(const char *dirname, int flags, int maxdepth, cli_ftw_cb callback, struct cli_ftw_cbdata *data, cli_ftw_pathchk pathchk);
static int handle_entry(struct dirent_data *entry, int flags, int maxdepth, cli_ftw_cb callback, struct cli_ftw_cbdata *data, cli_ftw_pathchk pathchk)
{
    if (!entry->is_dir) {
	return callback(entry->statbuf, entry->filename, entry->filename, visit_file, data);
    } else {
	return cli_ftw_dir(entry->dirname, flags, maxdepth, callback, data, pathchk);
    }
}

int cli_ftw(char *path, int flags, int maxdepth, cli_ftw_cb callback, struct cli_ftw_cbdata *data, cli_ftw_pathchk pathchk)
{
    struct stat statbuf;
    enum filetype ft = ft_unknown;
    struct dirent_data entry;
    int stated = 0;
    int ret;

    if (((flags & CLI_FTW_TRIM_SLASHES) || pathchk) && path[0] && path[1]) {
	char *pathend;
	/* trim slashes so that dir and dir/ behave the same when
	 * they are symlinks, and we are not following symlinks */
#ifndef _WIN32
	while (path[0] == *PATHSEP && path[1] == *PATHSEP) path++;
#endif
	pathend = path + strlen(path);
	while (pathend > path && pathend[-1] == *PATHSEP) --pathend;
	*pathend = '\0';
    }
    if(pathchk && pathchk(path, data) == 1)
	return CL_SUCCESS;
    ret = handle_filetype(path, flags, &statbuf, &stated, &ft, callback, data);
    if (ret != CL_SUCCESS)
	return ret;
    if (ft_skipped(ft))
	return CL_SUCCESS;
    entry.statbuf = stated ? &statbuf : NULL;
    entry.is_dir = ft == ft_directory;
    entry.filename = entry.is_dir ? NULL : strdup(path);
    entry.dirname = entry.is_dir ? path : NULL;
    if (entry.is_dir) {
	ret = callback(entry.statbuf, NULL, path, visit_directory_toplev, data);
	if (ret != CL_SUCCESS)
	    return ret;
    }
    return handle_entry(&entry, flags, maxdepth, callback, data, pathchk);
}

static int cli_ftw_dir(const char *dirname, int flags, int maxdepth, cli_ftw_cb callback, struct cli_ftw_cbdata *data, cli_ftw_pathchk pathchk)
{
    DIR *dd;
#if defined(HAVE_READDIR_R_3) || defined(HAVE_READDIR_R_2)
    union {
	struct dirent d;
	char b[offsetof(struct dirent, d_name) + NAME_MAX + 1];
    } result;
#endif
    struct dirent_data *entries = NULL;
    size_t i, entries_cnt = 0;
    int ret;

    if (maxdepth < 0) {
	/* exceeded recursion limit */
	ret = callback(NULL, NULL, dirname, warning_skipped_dir, data);
	return ret;
    }

    if((dd = opendir(dirname)) != NULL) {
	struct dirent *dent;
	int err;
	errno = 0;
	ret = CL_SUCCESS;
#ifdef HAVE_READDIR_R_3
	while(!(err = readdir_r(dd, &result.d, &dent)) && dent) {
#elif defined(HAVE_READDIR_R_2)
	while((dent = (struct dirent *) readdir_r(dd, &result.d))) {
#else
	while((dent = readdir(dd))) {
#endif
	    int stated = 0;
	    enum filetype ft;
	    char *fname;
	    struct stat statbuf;
	    struct stat *statbufp;

	    if(!strcmp(dent->d_name, ".") || !strcmp(dent->d_name, ".."))
		continue;
#ifdef _DIRENT_HAVE_D_TYPE
	    switch (dent->d_type) {
		case DT_DIR:
		    ft = ft_directory;
		    break;
		case DT_LNK:
		    if (!(flags & FOLLOW_SYMLINK_MASK)) {
			/* we don't follow symlinks, don't bother
			 * stating it */
			errno = 0;
			continue;
		    }
		    ft = ft_link;
		    break;
		case DT_REG:
		    ft = ft_regular;
		    break;
		case DT_UNKNOWN:
		    ft = ft_unknown;
		    break;
		default:
		    ft = ft_skipped_special;
		    break;
	    }
#else
	    ft = ft_unknown;
#endif
	    fname = (char *) cli_malloc(strlen(dirname) + strlen(dent->d_name) + 2);
	    if(!fname) {
		ret = callback(NULL, NULL, dirname, error_mem, data);
		if (ret != CL_SUCCESS)
		    break;
	    }
            if(!strcmp(dirname, PATHSEP))
		sprintf(fname, PATHSEP"%s", dent->d_name);
	    else
		sprintf(fname, "%s"PATHSEP"%s", dirname, dent->d_name);

	    if(pathchk && pathchk(fname, data) == 1) {
		free(fname);
		continue;
	    }

	    ret = handle_filetype(fname, flags, &statbuf, &stated, &ft, callback, data);
	    if (ret != CL_SUCCESS) {
		free(fname);
		break;
	    }

	    if (ft_skipped(ft)) { /* skip */
		free(fname);
		errno = 0;
		continue;
	    }

	    if (stated && (flags & CLI_FTW_NEED_STAT)) {
		statbufp = cli_malloc(sizeof(*statbufp));
		if (!statbufp) {
		    ret = callback(stated ? &statbuf : NULL, NULL, fname, error_mem, data);
		    free(fname);
		    if (ret != CL_SUCCESS)
			break;
		    else {
			errno = 0;
			continue;
		    }
		}
		memcpy(statbufp, &statbuf, sizeof(statbuf));
	    } else {
		statbufp = 0;
	    }

	    entries_cnt++;
	    entries = cli_realloc(entries, entries_cnt*sizeof(*entries));
	    if (!entries) {
		ret = callback(stated ? &statbuf : NULL, NULL, fname, error_mem, data);
		free(fname);
		if (statbufp)
		    free(statbufp);
		break;
	    } else {
		struct dirent_data *entry = &entries[entries_cnt-1];
		entry->filename = fname;
		entry->statbuf = statbufp;
		entry->is_dir = ft == ft_directory;
		entry->dirname = entry->is_dir ? fname : NULL;
#ifdef _XOPEN_UNIX
		entry->ino = dent->d_ino;
#else
		entry->ino = -1;
#endif
	    }
	    errno = 0;
	}
#ifndef HAVE_READDIR_R_3
	err = errno;
#endif
	closedir(dd);
	ret = CL_SUCCESS;
	if (err) {
	    char errs[128];
	    cli_errmsg("Unable to readdir() directory %s: %s\n", dirname,
		       cli_strerror(errno, errs, sizeof(errs)));
	    /* report error to callback using error_stat */
	    ret = callback(NULL, NULL, dirname, error_stat, data);
	    if (ret != CL_SUCCESS) {
		if (entries) {
		    for (i=0;i<entries_cnt;i++) {
			struct dirent_data *entry = &entries[i];
			free(entry->filename);
			free(entry->statbuf);
		    }
		    free(entries);
		}
		return ret;
	    }
	}

	if (entries) {
	    cli_qsort(entries, entries_cnt, sizeof(*entries), ftw_compare);
	    for (i = 0; i < entries_cnt; i++) {
		struct dirent_data *entry = &entries[i];
		ret = handle_entry(entry, flags, maxdepth-1, callback, data, pathchk);
		if (entry->is_dir)
		    free(entry->filename);
		if (entry->statbuf)
		    free(entry->statbuf);
		if (ret != CL_SUCCESS)
		    break;
	    }
	    for (i++;i<entries_cnt;i++) {
		struct dirent_data *entry = &entries[i];
		free(entry->filename);
		free(entry->statbuf);
	    }
	    free(entries);
	}
    } else {
	ret = callback(NULL, NULL, dirname, error_stat, data);
    }
    return ret;
}

/* strerror_r is not available everywhere, (and when it is there are two variants,
 * the XSI, and the GNU one, so provide a wrapper to make sure correct one is
 * used */
const char* cli_strerror(int errnum, char *buf, size_t len)
{
    char *err;
# ifdef CL_THREAD_SAFE
    pthread_mutex_lock(&cli_strerror_mutex);
#endif
    err = strerror(errnum);
    strncpy(buf, err, len);
# ifdef CL_THREAD_SAFE
    pthread_mutex_unlock(&cli_strerror_mutex);
#endif
    return buf;
}

static char *cli_md5buff(const unsigned char *buffer, unsigned int len, unsigned char *dig)
{
	unsigned char digest[16];
	char *md5str, *pt;
	cli_md5_ctx ctx;
	int i;


    cli_md5_init(&ctx);
    cli_md5_update(&ctx, buffer, len);
    cli_md5_final(digest, &ctx);

    if(dig)
	memcpy(dig, digest, 16);

    if(!(md5str = (char *) cli_calloc(32 + 1, sizeof(char))))
	return NULL;

    pt = md5str;
    for(i = 0; i < 16; i++) {
	sprintf(pt, "%02x", digest[i]);
	pt += 2;
    }

    return md5str;
}

unsigned int cli_rndnum(unsigned int max)
{
    if(name_salt[0] == 16) { /* minimizes re-seeding after the first call to cli_gentemp() */
	    struct timeval tv;
	gettimeofday(&tv, (struct timezone *) 0);
	srand(tv.tv_usec+clock()+rand());
    }

    return 1 + (unsigned int) (max * (rand() / (1.0 + RAND_MAX)));
}

char *cli_gentemp(const char *dir)
{
	char *name, *tmp;
        const char *mdir;
	unsigned char salt[16 + 32];
	int i;
    size_t len;

    mdir = dir ? dir : cli_gettmpdir();

    len = strlen(mdir) + 42;
    name = (char *) cli_calloc(len, sizeof(char));
    if(!name) {
	cli_dbgmsg("cli_gentemp('%s'): out of memory\n", mdir);
	return NULL;
    }

#ifdef CL_THREAD_SAFE
    pthread_mutex_lock(&cli_gentemp_mutex);
#endif

    memcpy(salt, name_salt, 16);

    for(i = 16; i < 48; i++)
	salt[i] = cli_rndnum(255);

    tmp = cli_md5buff(salt, 48, name_salt);

#ifdef CL_THREAD_SAFE
    pthread_mutex_unlock(&cli_gentemp_mutex);
#endif

    if(!tmp) {
	free(name);
	cli_dbgmsg("cli_gentemp('%s'): out of memory\n", mdir);
	return NULL;
    }

	snprintf(name, len, "%s"PATHSEP"clamav-%s", mdir, tmp);
    free(tmp);

    return(name);
}

int cli_gentempfd(const char *dir, char **name, int *fd)
{

    *name = cli_gentemp(dir);
    if(!*name)
	return CL_EMEM;

    *fd = open(*name, O_RDWR|O_CREAT|O_TRUNC|O_BINARY|O_EXCL, S_IRWXU);
    /*
     * EEXIST is almost impossible to occur, so we just treat it as other
     * errors
     */
   if(*fd == -1) {
	cli_errmsg("cli_gentempfd: Can't create temporary file %s: %s\n", *name, strerror(errno));
	free(*name);
	return CL_ECREAT;
    }

    return CL_SUCCESS;
}

int cli_regcomp(regex_t *preg, const char *pattern, int cflags)
{
    if (!strncmp(pattern, "(?i)", 4)) {
	pattern += 4;
	cflags |= REG_ICASE;
    }
    return cli_regcomp_real(preg, pattern, cflags);
}