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ECHILD error at waitpid on Red Hat systems (Peter Pramberger and

Browse source 
Sascha Runschke - 1250191)


git-svn-id: https://nagiosplug.svn.sourceforge.net/svnroot/nagiosplug/nagiosplug/trunk@1213 f882894a-f735-0410-b71e-b25c423dba1c
This commit is contained in:
Ton Voon 2005-09-12 10:31:29 +00:00
parent 3c554b72de
commit e85edd9e55
6 changed files with 147 additions and 2 deletions
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3
Makefile.am
View file

@ -5,7 +5,8 @@ SUBDIRS = intl lib plugins plugins-scripts m4 po
EXTRA_DIST = config.rpath \
ABOUT-NLS ACKNOWLEDGEMENTS AUTHORS BUGS CHANGES CODING FAQ LEGAL \
REQUIREMENTS SUPPORT THANKS \
NPTest.pm contrib pkg nagios-plugins.spec
NPTest.pm contrib pkg nagios-plugins.spec \
config_test/Makefile config_test/run_tests config_test/child_test.c
ACLOCAL_AMFLAGS = -I m4

10
config_test/Makefile Normal file
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@ -0,0 +1,10 @@
all: child_test.c
gcc -o child_test child_test.c
test:
./run_tests 10
clean:
rm -f child_test

77
config_test/child_test.c Normal file
View file

@ -0,0 +1,77 @@
// Base code taken from http://www-h.eng.cam.ac.uk/help/tpl/unix/fork.html
// Fix for redhat suggested by Ptere Pramberger, peter@pramberger.at
#include <unistd.h>
#include <sys/wait.h>
#include <stdio.h>
#include <sys/types.h>
#include <signal.h>
void popen_sigchld_handler (int);
int childtermd;
int main(){
char str[1024];
int pipefd[2];
pid_t pid;
int status, died;
if (signal (SIGCHLD, popen_sigchld_handler) == SIG_ERR) {
printf ("Cannot catch SIGCHLD\n");
_exit(-1);
}
pipe (pipefd);
switch(pid=fork()){
case -1:
printf("can't fork\n");
_exit(-1);
case 0 : // this is the code the child runs
close(1); // close stdout
// pipefd[1] is for writing to the pipe. We want the output
// that used to go to the standard output (file descriptor 1)
// to be written to the pipe. The following command does this,
// creating a new file descripter 1 (the lowest available)
// that writes where pipefd[1] goes.
dup (pipefd[1]); // points pipefd at file descriptor
// the child isn't going to read from the pipe, so
// pipefd[0] can be closed
close (pipefd[0]);
//These are the commands to run, with success commented. dig and nslookup only problems
//execl ("/bin/date","date",0); // 100%
//execl ("/bin/cat", "cat", "/etc/hosts", 0); // 100%
//execl ("/usr/bin/dig", "dig", "redhat.com", 0); // 69%
//execl("/bin/sleep", "sleep", "1", 0); // 100%
execl ("/usr/bin/nslookup","nslookup","redhat.com",0); // 90% (after 100 tests), 40% (after 10 tests)
//execl ("/bin/ping","ping","-c","1","localhost",0); // 100%
//execl ("/bin/ping","ping","-c","1","192.168.10.32",0); // 100%
_exit(0);
default: // this is the code the parent runs
close(0); // close stdin
// Set file descriptor 0 (stdin) to read from the pipe
dup (pipefd[0]);
// the parent isn't going to write to the pipe
close (pipefd[1]);
// Now read from the pipe
fgets(str, 1023, stdin);
//printf("1st line output is %s\n", str);
//while (!childtermd); // Uncomment this line to fix
died= wait(&status);
//printf("died=%d status=%d\n", died, status);
if (died > 0) _exit(0);
else _exit(1);
}
}
void
popen_sigchld_handler (int signo)
{
if (signo == SIGCHLD) {
//printf("Caught sigchld\n");
childtermd = 1;
}
}

16
config_test/run_tests Executable file
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@ -0,0 +1,16 @@
#!/bin/ksh
i=0
success=0
fail=0
while [[ $i -lt $1 ]] ; do
./child_test
if [[ $? -eq 0 ]] ; then
success=$(($success+1))
else
fail=$((fail+1))
fi
i=$(($i+1))
done
print "Success=$success Fail=$fail"
[[ $fail -gt 0 ]] && exit 1

16
configure.in
View file

@ -1520,6 +1520,22 @@ AC_SUBST(DEPLIBS)
AM_GNU_GETTEXT([no-libtool], [need-ngettext])
AM_GNU_GETTEXT_VERSION(0.11.5)
dnl Check for Redhat spopen problem
dnl Wierd problem where ECHILD is returned from a wait call in error
dnl Only appears to affect nslookup and dig calls. Only affects redhat around
dnl 2.6.9-11 (okay in 2.6.9-5). Redhat investigating root cause
dnl We patch plugins/popen.c
if echo $ac_cv_uname_r | egrep "\.EL$" >/dev/null 2>&1 ; then
AC_MSG_CHECKING(for redhat spopen problem)
( cd config_test && make && make test ) > /dev/null 2>&1
if test $? -eq 0 ; then
AC_MSG_RESULT(okay)
else
AC_MSG_RESULT(error)
AC_DEFINE(REDHAT_SPOPEN_ERROR, 1, "Problem on redhat with spopen")
fi
fi
dnl External libraries - see ACKNOWLEDGEMENTS
np_COREUTILS
np_CURL

27
plugins/popen.c
View file

@ -30,6 +30,9 @@ extern FILE *child_process;
FILE *spopen (const char *);
int spclose (FILE *);
#ifdef REDHAT_SPOPEN_ERROR
RETSIGTYPE popen_sigchld_handler (int);
#endif
RETSIGTYPE popen_timeout_alarm_handler (int);
#include <stdarg.h> /* ANSI C header file */
@ -67,6 +70,10 @@ char *pname = NULL; /* caller can set this from argv[0] */
/*extern pid_t *childpid = NULL; *//* ptr to array allocated at run-time */
static int maxfd; /* from our open_max(), {Prog openmax} */
#ifdef REDHAT_SPOPEN_ERROR
static volatile int childtermd = 0;
#endif
FILE *
spopen (const char *cmdstring)
{
@ -171,6 +178,12 @@ spopen (const char *cmdstring)
if (pipe (pfderr) < 0)
return (NULL); /* errno set by pipe() */
#ifdef REDHAT_SPOPEN_ERROR
if (signal (SIGCHLD, popen_sigchld_handler) == SIG_ERR) {
usage4 (_("Cannot catch SIGCHLD"));
}
#endif
if ((pid = fork ()) < 0)
return (NULL); /* errno set by fork() */
else if (pid == 0) { /* child */
@ -220,6 +233,10 @@ spclose (FILE * fp)
if (fclose (fp) == EOF)
return (1);
#ifdef REDHAT_SPOPEN_ERROR
while (!childtermd); /* wait until SIGCHLD */
#endif
while (waitpid (pid, &status, 0) < 0)
if (errno != EINTR)
return (1); /* error other than EINTR from waitpid() */
@ -239,8 +256,16 @@ static int openmax = 0;
#define OPEN_MAX_GUESS 256 /* if OPEN_MAX is indeterminate */
/* no guarantee this is adequate */
#ifdef REDHAT_SPOPEN_ERROR
RETSIGTYPE
popen_sigchld_handler (int signo)
{
if (signo == SIGCHLD)
childtermd = 1;
}
#endif
void
RETSIGTYPE
popen_timeout_alarm_handler (int signo)
{
int fh;