[Valgrind-users] Epoll

[Mukund S. <mu...@sh...>]

Hi
            I am trying to debug some large section of the code that
uses epoll. Unfortunately valgrind says epoll is an unimplemented system
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I have read the man page, tried to suppress the errors, but with no
success. Here is a sample code that causes the error.
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Error
=3D=3D23968=3D=3D Memcheck, a memory error detector for x86-linux.
=3D=3D23968=3D=3D Copyright (C) 2002-2003, and GNU GPL'd, by Julian =
Seward.
=3D=3D23968=3D=3D Using valgrind-2.1.0, a program supervision framework =
for
x86-linux.
=3D=3D23968=3D=3D Copyright (C) 2000-2003, and GNU GPL'd, by Julian =
Seward.
=3D=3D23968=3D=3D Estimated CPU clock rate is 2699 MHz
=3D=3D23968=3D=3D For more details, rerun with: -v
=3D=3D23968=3D=3D=20
--23968-- WARNING: unhandled syscall: 254
--23968-- Do not panic.  You may be able to fix this easily.
--23968-- Read the file README_MISSING_SYSCALL_OR_IOCTL.
=3D=3D23968=3D=3D Invalid read of size 1
=3D=3D23968=3D=3D    at 0x961D9A: strcmp (in /lib/ld-2.3.2.so)
=3D=3D23968=3D=3D    by 0x40322499: dl_open_worker (in =
/lib/i686/libc-2.3.2.so)
=3D=3D23968=3D=3D    by 0x95C735: _dl_catch_error_internal (in =
/lib/ld-2.3.2.so)
=3D=3D23968=3D=3D    by 0x40322308: __GI__dl_open (in =
/lib/i686/libc-2.3.2.so)
=3D=3D23968=3D=3D  Address 0xFFFFE210 is not stack'd, malloc'd or free'd
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=3D=3D23968=3D=3D Invalid read of size 1
=3D=3D23968=3D=3D    at 0x961D9A: strcmp (in /lib/ld-2.3.2.so)
=3D=3D23968=3D=3D    by 0x95C0FA: openaux (in /lib/ld-2.3.2.so)
=3D=3D23968=3D=3D    by 0x95C735: _dl_catch_error_internal (in =
/lib/ld-2.3.2.so)
=3D=3D23968=3D=3D    by 0x95BC80: _dl_map_object_deps_internal (in
/lib/ld-2.3.2.so)
=3D=3D23968=3D=3D  Address 0xFFFFE210 is not stack'd, malloc'd or free'd
=3D=3D23968=3D=3D=20
=3D=3D23968=3D=3D Conditional jump or move depends on uninitialised =
value(s)
=3D=3D23968=3D=3D    at 0x416C73FE: getanswer_r (in =
/lib/libnss_dns-2.3.2.so)
=3D=3D23968=3D=3D    by 0x416C60B3: _nss_dns_gethostbyname2_r (in
/lib/libnss_dns-2.3.2.so)
=3D=3D23968=3D=3D    by 0x416C62AB: _nss_dns_gethostbyname_r (in
/lib/libnss_dns-2.3.2.so)
=3D=3D23968=3D=3D    by 0x40304CCA: gethostbyname_r@@GLIBC_2.1.2 (in
/lib/i686/libc-2.3.2.so)
=3D=3D23968=3D=3D=20
=3D=3D23968=3D=3D Conditional jump or move depends on uninitialised =
value(s)
=3D=3D23968=3D=3D    at 0x416C7401: getanswer_r (in =
/lib/libnss_dns-2.3.2.so)
=3D=3D23968=3D=3D    by 0x416C60B3: _nss_dns_gethostbyname2_r (in
/lib/libnss_dns-2.3.2.so)
=3D=3D23968=3D=3D    by 0x416C62AB: _nss_dns_gethostbyname_r (in
/lib/libnss_dns-2.3.2.so)
=3D=3D23968=3D=3D    by 0x40304CCA: gethostbyname_r@@GLIBC_2.1.2 (in
/lib/i686/libc-2.3.2.so)
--23968-- WARNING: unhandled syscall: 255
--23968-- Do not panic.  You may be able to fix this easily.
--23968-- Read the file README_MISSING_SYSCALL_OR_IOCTL.
--23968-- WARNING: unhandled syscall: 256
--23968-- Do not panic.  You may be able to fix this easily.
--23968-- Read the file README_MISSING_SYSCALL_OR_IOCTL.
=3D=3D23968=3D=3D Warning: invalid file descriptor -1 in syscall close()
=3D=3D23968=3D=3D=20
=3D=3D23968=3D=3D ERROR SUMMARY: 24 errors from 4 contexts (suppressed: =
5 from
1)
=3D=3D23968=3D=3D malloc/free: in use at exit: 0 bytes in 0 blocks.
=3D=3D23968=3D=3D malloc/free: 66 allocs, 66 frees, 5227 bytes =
allocated.
=3D=3D23968=3D=3D For a detailed leak analysis,  rerun with: =
--leak-check=3Dyes
=3D=3D23968=3D=3D For counts of detected errors, rerun with: -v
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Code
=3D=3D=3D=3D
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#include <sys/epoll.h>
#include <netdb.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
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#define MAX_BUFF_LEN 4096
#define MAX_EVENTS_SIZE 25
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int main() {
  int ed =3D epoll_create(256);
  char buf[MAX_BUFF_LEN];
  char output_buff[MAX_BUFF_LEN];
  struct epoll_event events[MAX_EVENTS_SIZE];
  struct hostent hostEntity;
  struct hostent *pResolvedHost;
  struct  sockaddr_in     server;
  int syserrno,i,numFds;
  int sockfd;
  struct epoll_event ev;
  char data[] =3D"GET / HTTP/1.0\r\n\r\n";
  int status =3D gethostbyname_r("www.yahoo.com",&hostEntity, buf,
MAX_BUFF_LEN,&pResolvedHost, &syserrno);
  if (status !=3D 0) {
    fprintf(stderr,"Cannot resolve the hostname. gethostbyname_r failed
");
    exit(-1);
  }
  memset((char *) &server,0, sizeof(server));
  memmove((char *) &server.sin_addr,
pResolvedHost->h_addr,pResolvedHost->h_length);
  server.sin_family =3D pResolvedHost->h_addrtype;
  server.sin_port =3D (unsigned short) htons( 80 );
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  sockfd =3D socket(PF_INET, SOCK_STREAM, IPPROTO_TCP);
  status =3D connect(sockfd,(struct sockaddr *)&server,sizeof(server));
  if (status !=3D 0) {
    fprintf(stderr,"Cannot connect to host \n");
  }
  write (sockfd,data,strlen(data));
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  ev.events =3D EPOLLIN|EPOLLET;
  ev.data.fd =3D sockfd;
  status =3D epoll_ctl(ed,EPOLL_CTL_ADD,sockfd,&ev);
  numFds =3D epoll_wait(ed, events,MAX_EVENTS_SIZE, -1);
  for (i=3D0;i<numFds; i++) {
    int len =3D0;
    while ( (len =3Dread(events[i].data.fd,output_buff,MAX_BUFF_LEN)) >0 =
)
{
      write(1,output_buff,len);
    }
    close(events[i].data.fd);
  }
  close(ed);
  return 0;
}
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