From e85edd9e55d79b7e475f009df64accb65f317905 Mon Sep 17 00:00:00 2001 From: Ton Voon Date: Mon, 12 Sep 2005 10:31:29 +0000 Subject: [PATCH] ECHILD error at waitpid on Red Hat systems (Peter Pramberger and Sascha Runschke - 1250191) git-svn-id: https://nagiosplug.svn.sourceforge.net/svnroot/nagiosplug/nagiosplug/trunk@1213 f882894a-f735-0410-b71e-b25c423dba1c --- Makefile.am | 3 +- config_test/Makefile | 10 ++++++ config_test/child_test.c | 77 ++++++++++++++++++++++++++++++++++++++++ config_test/run_tests | 16 +++++++++ configure.in | 16 +++++++++ plugins/popen.c | 27 +++++++++++++- 6 files changed, 147 insertions(+), 2 deletions(-) create mode 100644 config_test/Makefile create mode 100644 config_test/child_test.c create mode 100755 config_test/run_tests diff --git a/Makefile.am b/Makefile.am index a7c5ffc..cc46a46 100644 --- a/Makefile.am +++ b/Makefile.am @@ -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 diff --git a/config_test/Makefile b/config_test/Makefile new file mode 100644 index 0000000..295696e --- /dev/null +++ b/config_test/Makefile @@ -0,0 +1,10 @@ + +all: child_test.c + gcc -o child_test child_test.c + +test: + ./run_tests 10 + +clean: + rm -f child_test + diff --git a/config_test/child_test.c b/config_test/child_test.c new file mode 100644 index 0000000..e7d8210 --- /dev/null +++ b/config_test/child_test.c @@ -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 +#include +#include +#include +#include +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; + } +} diff --git a/config_test/run_tests b/config_test/run_tests new file mode 100755 index 0000000..e41db23 --- /dev/null +++ b/config_test/run_tests @@ -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 diff --git a/configure.in b/configure.in index 5453fe1..4f9dc1c 100644 --- a/configure.in +++ b/configure.in @@ -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 diff --git a/plugins/popen.c b/plugins/popen.c index 062cf27..f681069 100644 --- a/plugins/popen.c +++ b/plugins/popen.c @@ -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 /* 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; -- 2.30.2