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There are three functions available: <PRE> int cl_loaddb(const char *filename, struct cl_node **root, int *virnum); int cl_loaddbdir(const char *dirname, struct cl_node **root, int *virnum); const char *cl_retdbdir(void); </PRE> <code>cl_loaddb()</code> loads a particular database, <code>cl_loaddbdir()</code> loads all <I>.cvd</I> (and older <I>.db</I>, .db2) databases from a directory <code>dirname</code>. <code>cl_retdbdir()</code> returns a hardcoded database directory path. Initial internal database (Aho-Corasick tree, trie; see <A HREF="node71.html#engine">6.3</A>) will be saved under <code>root</code> and a number of signatures loaded will be <B>added</B> <A NAME="tex2html115" HREF="footnode.html#foot696"><SUP>8</SUP></A> to <code>virnum</code>. Pointer to the trie must initially point to NULL. If you don't care about number of signatures pass NULL as a third argument. <code>cl_loaddb</code> functions return 0 on success and an other value on failure. <PRE> struct cl_node *root = NULL; int ret; ret = cl_loaddbdir(cl_retdbdir(), &root, NULL); </PRE> There's an elegant way to print libclamav's error codes: <PRE> const char *cl_strerror(int clerror); </PRE> <code>cl_strerror()</code> returns a (statically allocated) string describing a <code>clerror</code> code: <PRE> if(ret) { printf("cl_loaddbdir() error: %s\n", cl_strerror(ret)); exit(1); } </PRE> When database is loaded you must build the final trie with: <PRE> int cl_buildtrie(struct cl_node *root); </PRE> In our example: <PRE> if((ret = cl_buildtrie(root))) printf("cl_buildtrie() error: %s\n", cl_strerror(ret)); </PRE> Now you can scan a buffer, a descriptor or a file with: <PRE> int cl_scanbuff(const char *buffer, unsigned int length, const char **virname, const struct cl_node *root); int cl_scandesc(int desc, const char **virname, unsigned long int *scanned, const struct cl_node *root, const struct cl_limits *limits, int options); int cl_scanfile(const char *filename, const char **virname, unsigned long int *scanned, const struct cl_node *root, const struct cl_limits *limits, int options); </PRE> All the functions save a virus name address under <code>virname</code> pointer. It points to a name in the trie structure thus it can't be released directly. <code>cl_scandesc()</code> and <code>cl_scanfile()</code> can increase the <code>scanned</code> value in <code>CL_COUNT_PRECISION</code> units, they also support archive limits: <PRE> struct cl_limits { int maxreclevel; /* maximal recursion level */ int maxfiles; /* maximal number of files to be * scanned within an archive */ int maxratio; /* maximal compression ratio */ short archivememlim; /* limit memory usage for bzip2 (0/1) */ long int maxfilesize; /* files in an archive larger than * this value will not be scanned */ }; </PRE> The last argument in the <code>cl_scan</code> family configures the scan engine. It supports the following flags: <UL> <LI><B>CL_RAW</B> <BR> It does nothing. Please use it (alone) if you don't want to scan any special files. </LI> <LI><B>CL_ARCHIVE</B> <BR> This flag enables the transparent archive scanning. </LI> <LI><B>CL_DISABLERAR</B> <BR> Disables the built-in RAR unpacker which is known to cause memory leaks. </LI> <LI><B>CL_ENCRYPTED</B> <BR> Marks encrypted archives as viruses (Encrypted.Zip, Encrypted.RAR). </LI> <LI><B>CL_MAIL</B> <BR> Required to scan various types of mail files. </LI> <LI><B>CL_OLE2</B> <BR> Enables support for Microsoft Office document files. </LI> </UL> All functions return 0 (<code>CL_CLEAN</code>) if the file is clean, <code>CL_VIRUS</code> when virus is detected and an other value on failure. <PRE> struct cl_limits limits; const char *virname; memset(&limits, 0, sizeof(struct cl_limits)); /* maximal number of files in archive */; limits.maxfiles = 1000 /* maximal archived file size == 10 MB */ limits.maxfilesize = 10 * 1048576; /* maximal recursion level */ limits.maxreclevel = 5; /* maximal compression ratio */ limits.maxratio = 200; /* disable memory limit for bzip2 scanner */ limits.archivememlim = 0; if((ret = cl_scanfile("/home/zolw/test", &virname, NULL, root, &limits, CL_ARCHIVE | CL_MAIL | CL_OLE2)) == CL_VIRUS) { printf("Detected %s virus.\n", virname); } else { printf("No virus detected.\n"); if(ret != CL_CLEAN) printf("Error: %s\n", cl_strerror(ret)); } </PRE> Release the trie if you no longer need it: <PRE> void cl_freetrie(struct cl_node *root); </PRE> You will find an example scanner in clamav sources (/example). All programs based on libclamav must be linked against it: <PRE> gcc -Wall ex1.c -o ex1 -lclamav </PRE> Enjoy ! <P> <HR> <!--Navigation Panel--> <A NAME="tex2html1194" HREF="node70.html"> <IMG WIDTH="37" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="next" SRC="/usr/share/latex2html/icons/next.png"></A> <A NAME="tex2html1190" HREF="node68.html"> <IMG WIDTH="26" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="up" SRC="/usr/share/latex2html/icons/up.png"></A> <A NAME="tex2html1184" HREF="node68.html"> <IMG WIDTH="63" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="previous" SRC="/usr/share/latex2html/icons/prev.png"></A> <A NAME="tex2html1192" HREF="node1.html"> <IMG WIDTH="65" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="contents" SRC="/usr/share/latex2html/icons/contents.png"></A> <BR> <B> Next:</B> <A NAME="tex2html1195" HREF="node70.html">Database reloading</A> <B> Up:</B> <A NAME="tex2html1191" HREF="node68.html">LibClamAV</A> <B> Previous:</B> <A NAME="tex2html1185" HREF="node68.html">LibClamAV</A>   <B> <A NAME="tex2html1193" HREF="node1.html">Contents</A></B> <!--End of Navigation Panel--> <ADDRESS> Tomasz Kojm 2004-05-18 </ADDRESS> </BODY> </HTML>