[uClibc] nptl strace

[Rogelio Serrano]

Hi All,

Im trying to understand nptl and the new kernel system calls 
associated with it. Attached is the strace of the system calls 
made by a test pogram.

#include <stdlib.h>
#include <stdio.h>
#include <pthread.h>

void *
service_loop(void * arg)
{
     printf("thread\n");
     return NULL;
}

int
main()
{
     pthread_t tid;
     pthread_create(&tid, NULL, service_loop, NULL);
     while(1);
}

this is the trace:

execve("./a.out", ["./a.out"], [/* 33 vars */]) = 0
uname({sys="Linux", node="debian", ...}) = 0
brk(0)                                  = 0x804a000
old_mmap(NULL, 4096, PROT_READ|PROT_WRITE, 
MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x40017000
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such 
file or directory)
open("/etc/ld.so.preload", O_RDONLY)    = -1 ENOENT (No such 
file or directory)
open("/etc/ld.so.cache", O_RDONLY)      = 3
fstat64(3, {st_mode=S_IFREG|0644, st_size=39146, ...}) = 0
old_mmap(NULL, 39146, PROT_READ, MAP_PRIVATE, 3, 0) = 0x40018000
close(3)                                = 0
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such 
file or directory)
open("/lib/tls/i686/cmov/libpthread.so.0", O_RDONLY) = 3
read(3, 
"\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0\3\0\1\0\0\0\20E\0\000"..., 
512) = 512
fstat64(3, {st_mode=S_IFREG|0644, st_size=82361, ...}) = 0
old_mmap(NULL, 64928, PROT_READ|PROT_EXEC, MAP_PRIVATE, 3, 0) = 
0x40022000
old_mmap(0x4002f000, 4096, PROT_READ|PROT_WRITE, 
MAP_PRIVATE|MAP_FIXED, 3, 0xd000) = 0x4002f000
old_mmap(0x40030000, 7584, PROT_READ|PROT_WRITE, 
MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x40030000
close(3)                                = 0
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such 
file or directory)
open("/lib/tls/i686/cmov/libc.so.6", O_RDONLY) = 3
read(3, 
"\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0\3\0\1\0\0\0\200X\1"..., 
512) = 512
fstat64(3, {st_mode=S_IFREG|0644, st_size=1271196, ...}) = 0
old_mmap(NULL, 1281580, PROT_READ|PROT_EXEC, MAP_PRIVATE, 3, 0) 
= 0x40032000
old_mmap(0x40160000, 36864, PROT_READ|PROT_WRITE, 
MAP_PRIVATE|MAP_FIXED, 3, 0x12d000) = 0x40160000
old_mmap(0x40169000, 7724, PROT_READ|PROT_WRITE, 
MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x40169000
close(3)                                = 0
old_mmap(NULL, 4096, PROT_READ|PROT_WRITE, 
MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x4016b000
set_thread_area({entry_number:-1 -> 6, base_addr:0x4016b5a0, 
limit:1048575, seg_32bit:1, contents:0, read_exec_only:0, 
limit_in_pages:1, seg_not_present:0, useable:1}) = 0
munmap(0x40018000, 39146)               = 0
set_tid_address(0x4016b5e8)             = 1412
rt_sigaction(SIGRTMIN, {0x40026470, [], SA_SIGINFO}, NULL, 8) = 
0
rt_sigprocmask(SIG_UNBLOCK, [RTMIN], NULL, 8) = 0
getrlimit(RLIMIT_STACK, {rlim_cur=8192*1024, 
rlim_max=RLIM_INFINITY}) = 0
mmap2(NULL, 8392704, PROT_READ|PROT_WRITE|PROT_EXEC, 
MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x4016c000
brk(0)                                  = 0x804a000
brk(0x806b000)                          = 0x806b000
brk(0)                                  = 0x806b000
mprotect(0x4016c000, 4096, PROT_NONE)   = 0
clone(child_stack=0x4096cb48, 
flags=CLONE_VM|CLONE_FS|CLONE_FILES|CLONE_SIGHAND|CLONE_THREAD|CLONE_SYSVSEM|CLONE_SETTLS|CLONE_PARENT_SETTID|CLONE_CHILD_CLEARTID|CLONE_DETACHED, 
parent_tidptr=0x4096cbf8, {entry_number:6, 
base_addr:0x4096cbb0, limit:1048575, seg_32bit:1, contents:0, 
read_exec_only:0, limit_in_pages:1, seg_not_present:0, 
useable:1}, child_tidptr=0x4096cbf8) = 1413


Can anybody help me decipher this? And can  we infer from this 
trace what structures are required to implement nptl style 
threads for uClibc?