Hi * Jinhui Li ([EMAIL PROTECTED]) wrote: > I am browsing the source code. And want to debug it to figure out how it > works. > > So, somebody please tell me how to debug ( with GDB ) or where can I find > information that I need.
Compile Wget with debug informations (-g flag for GCC) and then run wget into GDB. You can now use and see variables name, structs, function name instead of unfriendly adresses and raw bytes, ... I can't show every aspect of GDB. Use your favorite search engine for more usage info. Hints: http://www.gnu.org/software/gdb/documentation/ http://www.google.com/search?hl=en&q=gdb+howto&btnG=Search Quick example: $ CFLAGS="-g" ./configure $ make $ cd src/ $ gdb ./wget (gdb) set args -P tmpdir/ -p www.google.com (gdb) break retrieve_url Breakpoint 1 at 0x420260: file retr.c, line 601. (gdb) break url_parse Breakpoint 2 at 0x4231a0: file url.c, line 644. (gdb) run Starting program: /home/xav/xav/sxav/src/wget -P tmpdir/ -p www.google.com [Thread debugging using libthread_db enabled] [New Thread 0x7f1ad48566e0 (LWP 6580)] [Switching to Thread 0x7f1ad48566e0 (LWP 6580)] Breakpoint 2, url_parse (url=0x665810 "http://www.google.com";, error=0x7fffdc866aa0, iri=0x665830) at url.c:644 644 { (gdb) continue Continuing. Breakpoint 1, retrieve_url (origurl=0x665ae0 "http://www.google.com/";, file=0x7fffdc866a70, newloc=0x7fffdc866a78, refurl=0x0, dt=0x7fffdc866a98, recursive=false, iri=0x665830) at retr.c:601 601 { (gdb) bt #0 retrieve_url (origurl=0x665ae0 "http://www.google.com/";, file=0x7fffdc866a70, newloc=0x7fffdc866a78, refurl=0x0, dt=0x7fffdc866a98, recursive=false, iri=0x665830) at retr.c:601 #1 0x000000000041ed48 in retrieve_tree (start_url=0x665810 "http://www.google.com";, pi=0x0) at recur.c:292 #2 0x000000000041bc31 in main (argc=5, argv=0x7fffdc866d28) at main.c:1201 (gdb) p iri $1 = (struct iri *) 0x665830 (gdb) p *iri $2 = {uri_encoding = 0x665850 "UTF-8", content_encoding = 0x0, utf8_encode = false} (gdb) p iri->uri_encoding $3 = 0x665850 "UTF-8" (gdb) continue Continuing. Breakpoint 2, url_parse (url=0x665b20 "http://www.google.com/";, error=0x7fffdc8669e0, iri=0x665830) at url.c:644 644 { (gdb) continue Continuing. --2008-09-01 14:57:15-- http://www.google.com/ Resolving www.google.com (www.google.com)... 66.249.93.99 Connecting to www.google.com (www.google.com)|66.249.93.99|:80... connected. HTTP request sent, awaiting response... 302 Found Location: http://www.google.be/ [following] Breakpoint 2, url_parse (url=0x669660 "http://www.google.be/";, error=0x7fffdc8669e0, iri=0x665830) at url.c:644 644 { (gdb) continue Continuing. --2008-09-01 14:57:18-- http://www.google.be/ Resolving www.google.be (www.google.be)... 66.249.93.104 Connecting to www.google.be (www.google.be)|66.249.93.104|:80... connected. HTTP request sent, awaiting response... 200 OK Length: unspecified [text/html] Saving to: `tmpdir/www.google.be/index.html' [ <=> ] 6,146 --.-K/s in 0.07s 2008-09-01 14:57:18 (82.1 KB/s) - `tmpdir/www.google.be/index.html' saved [6146] Breakpoint 2, url_parse (url=0x665ae0 "http://www.google.com/";, error=0x0, iri=0x0) at url.c:644 644 { (gdb) q The program is running. Exit anyway? (y or n) y Regards, Saint Xavier.
