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Calling libiptc API from a separate thread in a C program throws segmentati

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I am working on performing iptables update through a custom c program using
 libiptc.
 
 The requirement is to invoke iptc APIs from a separate thread every 2 seconds.
 
 I have written a simple C program to try out invoking of iptc APIs from a
 separate thread. The c program is pasted below:
 
 /*** thread_iptc.c ***/
 
 #include <pthread.h>
 #include <stdio.h>
 #include <stdlib.h>
 
 void* thread_func(void* unused)
 {
 struct iptc_handle *handle = NULL;
 char *table = "filter";
 
 while (1)
 {
 printf("nthread_func(): While loop.n");
 handle = iptc_init(table);
 if (handle) {
 printf("thread_func(): handle is not NULL.n");
 iptc_free(handle);
 }
 else
 printf("thread_func(): handle is NULL.n");
 
 sleep(2);
 }
 
 return NULL;
 }
 
 
 int main()
 {
 struct iptc_handle *handle = NULL;
 char *table = "filter";
 pthread_t thread_id;
 
 handle = iptc_init(table);
 if (handle) {
 printf("main(): handle is not NULL.n");
 iptc_free(handle);
 }
 else
 printf("main(): handle is NULL.n");
 
 
 pthread_create(&thread_id, NULL, &thread_func, NULL);
 pthread_join(thread_id, NULL);
 
 return 0;
 }
 
 The problem, I am facing is that call to both iptc_init() and iptc_free()
works
 well when called from main function. However, call to iptc_free() fails with
 "Segmentation Fault" when called from thread_func().
 
 Program Output:
 
 # ./test
 main(): handle is not NULL.
 
 thread_func(): While loop.
 thread_func(): handle is not NULL.
 Segmentation fault
 
 Compilation:
 
 # gcc -o test thread_iptc.c -lpthread -lext4 -lext6 -lip4tc -lip6tc -liptc
 -lxtables -ldl
 
 
 (gdb) backtrace
 #0  0x00007ffff79be303 in iptc_free () from /lib64/libip4tc.so.0
 #1  0x00000000004007f3 in thread_func ()
 #2  0x00007ffff7bc77e1 in start_thread () from /lib64/libpthread.so.0
 #3  0x00007ffff6efb8ed in clone () from /lib64/libc.so.6
 
 
 Am I missing something during compilation or while invoking a new thread?
 
 
 Thanks

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Calling libiptc API from a separate thread in a C program throws segmentati kkgarg78 <nospam_kamalkgarg@gmail.com.invalid> - 2012-01-17 04:40 -0600
  Re: Calling libiptc API from a separate thread in a C program throws segmentati Kaz Kylheku <kaz@kylheku.com> - 2012-01-17 18:48 +0000
    Re: Calling libiptc API from a separate thread in a C program throws segmentati Jorgen Grahn <grahn+nntp@snipabacken.se> - 2012-01-17 21:26 +0000
      Re: Calling libiptc API from a separate thread in a C program throws segmentati Kaz Kylheku <kaz@kylheku.com> - 2012-01-17 22:03 +0000
        Re: Calling libiptc API from a separate thread in a C program throws segmentati Richard Kettlewell <rjk@greenend.org.uk> - 2012-01-17 22:07 +0000
          Re: Calling libiptc API from a separate thread in a C program throws segmentati Kaz Kylheku <kaz@kylheku.com> - 2012-01-17 22:34 +0000
            Re: Calling libiptc API from a separate thread in a C program throws segmentati Richard Kettlewell <rjk@greenend.org.uk> - 2012-01-17 22:51 +0000
              Re: Calling libiptc API from a separate thread in a C program throws segmentati Kaz Kylheku <kaz@kylheku.com> - 2012-01-17 23:13 +0000
        Re: Calling libiptc API from a separate thread in a C program throws segmentati Jorgen Grahn <grahn+nntp@snipabacken.se> - 2012-01-17 22:56 +0000
  Re: Calling libiptc API from a separate thread in a C program throws segmentati Richard Kettlewell <rjk@greenend.org.uk> - 2012-01-21 11:29 +0000

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