setting breakpoint in system call. Solaris vs. Windows
Java CAPS, like other SOA/EAI products, has an adapter for ftp. We recently had to test timeout feature when ftp server hangs on logon. To reproduce the problem, I used debugger to set breakpoint in system call.
Breakpoint - Wikipedia, the free encyclopedia
a breakpoint is a means of acquiring knowledge about a program during its execution
1. Solaris
We know ftp server will read/write some stuff from/to network while authenticating. I used write() system call this time.
# mdb -o follow_fork_mode=child,follow_exec_mode=follow -p $(pgrep inetd) Loading modules: [ ld.so.1 libumem.so.1 libuutil.so.1 libc.so.1 libnvpair.so.1 libsysevent.so.1 ] > ::sysbp write > :c mdb: target forked child process 27158 (debugger following child) <-- ftp client tries to connect mdb: target performed exec of /usr/sbin/in.ftpd mdb: stop on entry to write mdb: target stopped at: libc.so.1`_write+8: ta 8 >
2. Windows
What is the equivalent of write() system call on Windows? I tried ntdll.dll!NtWriteFile but it didn't work. NtWriteFile() may be strictly for local file system write. I used ws2_32.dll!send instead.
Install Debugging Tools for Windows 32-bit Version
Current Release version 6.9.3.113 - April 29, 2008 [17.5 MB]
$ tasklist /svc | grep -i ftp inetinfo.exe 2400 IISADMIN, MSFtpsvc $ cdb -p 2400 Microsoft (R) Windows Debugger Version 6.6.0007.5 *** wait with pending attach Symbol search path is: SRV*e:\symbols*http://msdl.microsoft.com/download/symbols Executable search path is: ModLoad: 01000000 01006000 D:\WINDOWS\system32\inetsrv\inetinfo.exe ModLoad: 7c950000 7ca2a000 D:\WINDOWS\system32\ntdll.dll [...] ModLoad: 71aa0000 71ab7000 D:\WINDOWS\system32\WS2_32.dll [...] 0:016> X *!send 719e619f mswsock!send =71ab06b2 WS2_32!send = 0:016> bp WS2_32!send 0:016> g Breakpoint 0 hit <-- ftp client tries to connect eax=00000000 ebx=6808374c ecx=0193f5d4 edx=0193f3a0 esi=0000001b edi=68083554 eip=71ab06b2 esp=0193f5b4 ebp=0193f5e0 iopl=0 nv up ei pl zr na pe nc cs=001b ss=0023 ds=0023 es=0023 fs=003b gs=0000 efl=00000246 WS2_32!send: 71ab06b2 8bff mov edi,edi
