Re: How to trace the send() in client call

[Robert Clove <cloverobert@xxxxxxxxx>]

Actually what i want to trace is what all netfilter calls the packet trace till it reach destination.
Will strace do that because i just ran the strace with client and the server sample program http://www.codeproject.com/Articles/586000/Networking-and-Socket-programming-tutorial-in-C

For the client i got the following result
 strace -o /root/Desktop/traceq.txt ./cli
Message from server
[root@client Desktop]# cat traceq.txt
execve("./cli", ["./cli"], [/* 27 vars */]) = 0
brk(0)                                  = 0x159c000
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fea4c159000
access("/etc/ld.so.preload", R_OK)      = -1 ENOENT (No such file or directory)
open("/etc/ld.so.cache", O_RDONLY)      = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=68323, ...}) = 0
mmap(NULL, 68323, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7fea4c148000
close(3)                                = 0
open("/lib64/libc.so.6", O_RDONLY)      = 3
read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0000\356Ah?\0\0\0"..., 832) = 832
fstat(3, {st_mode=S_IFREG|0755, st_size=1926800, ...}) = 0
mmap(0x3f68400000, 3750152, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x3f68400000
mprotect(0x3f6858b000, 2093056, PROT_NONE) = 0
mmap(0x3f6878a000, 20480, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x18a000) = 0x3f6878a000
mmap(0x3f6878f000, 18696, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x3f6878f000
close(3)                                = 0
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fea4c147000
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fea4c146000
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fea4c145000
arch_prctl(ARCH_SET_FS, 0x7fea4c146700) = 0
mprotect(0x3f6878a000, 16384, PROT_READ) = 0
mprotect(0x3f67e1f000, 4096, PROT_READ) = 0
munmap(0x7fea4c148000, 68323)           = 0
socket(PF_INET, SOCK_STREAM, IPPROTO_IP) = 3
connect(3, {sa_family=AF_INET, sin_port=htons(5000), sin_addr=inet_addr("192.168.60.3")}, 16) = 0
read(3, "Message from server", 1023)    = 19
fstat(1, {st_mode=S_IFCHR|0620, st_rdev=makedev(136, 6), ...}) = 0
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fea4c158000
write(1, "Message from server\n", 20)   = 20
read(3, "", 1023)                       = 0
exit_group(0) 

And for the server i got the following result

strace -o /root/Desktop/trace.txt ./ser
socket retrieve success
^C
[root@server Desktop]# cat trace
traceprocess.sh  trace.txt
[root@server Desktop]# cat trace.txt
execve("./ser", ["./ser"], [/* 26 vars */]) = 0
brk(0)                                  = 0x1727000
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f57e614c000
access("/etc/ld.so.preload", R_OK)      = -1 ENOENT (No such file or directory)
open("/etc/ld.so.cache", O_RDONLY)      = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=69902, ...}) = 0
mmap(NULL, 69902, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f57e613a000
close(3)                                = 0
open("/lib64/libc.so.6", O_RDONLY)      = 3
read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0000\356\1\2444\0\0\0"..., 832) = 832
fstat(3, {st_mode=S_IFREG|0755, st_size=1926800, ...}) = 0
mmap(0x34a4000000, 3750152, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x34a4000000
mprotect(0x34a418b000, 2093056, PROT_NONE) = 0
mmap(0x34a438a000, 20480, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x18a000) = 0x34a438a000
mmap(0x34a438f000, 18696, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x34a438f000
close(3)                                = 0
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f57e6139000
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f57e6138000
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f57e6137000
arch_prctl(ARCH_SET_FS, 0x7f57e6138700) = 0
mprotect(0x34a438a000, 16384, PROT_READ) = 0
mprotect(0x34a3a1f000, 4096, PROT_READ) = 0
munmap(0x7f57e613a000, 69902)           = 0
socket(PF_INET, SOCK_STREAM, IPPROTO_IP) = 3
fstat(1, {st_mode=S_IFCHR|0620, st_rdev=makedev(136, 2), ...}) = 0
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f57e614b000
write(1, "socket retrieve success\n", 24) = 24
bind(3, {sa_family=AF_INET, sin_port=htons(5000), sin_addr=inet_addr("0.0.0.0")}, 16) = 0
listen(3, 10)                           = 0
accept(3, 0, NULL)                      = 4
write(4, "Message from server", 19)     = 19
close(4)                                = 0
rt_sigprocmask(SIG_BLOCK, [CHLD], [], 8) = 0
rt_sigaction(SIGCHLD, NULL, {SIG_DFL, [], 0}, 8) = 0
rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0
nanosleep({1, 0}, 0x7fffb1502640)       = 0
accept(3, 0, NULL)                      = ? ERESTARTSYS (To be restarted)
--- SIGINT (Interrupt) @ 0 (0) ---
+++ killed by SIGINT +++

Regards

On Tue, May 27, 2014 at 9:26 PM, Augusto Mecking Caringi <augustocaringi@xxxxxxxxx> wrote:

On Tue, May 27, 2014 at 8:31 AM, Robert Clove <cloverobert@xxxxxxxxx> wrote:

But there will be other packets also coming from the network like if some one is browsing the net on mozilla.

I only want to trace the send() calls that i have used in my code,is that possible?

Robert, 

    You must specify the PID of your process (to attach strace to a running process), or run your program through strace.

    Yon can use grep to filter only the write syscall.

    Regards.

--  

Augusto Mecking Caringi

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