In article <[EMAIL PROTECTED]> you wrote: > Guochun Shi wrote: >> excellent, this fixed bug 952 >> >> -Guochun >> >> linux-ha-cvs@lists.linux-ha.org wrote: >> >>> linux-ha CVS committal >>> >>> Author : sunjd >>> Host : Project : linux-ha >>> Module : lib >>> >>> Dir : linux-ha/lib/plugins/stonith/external >>> >>> >>> Modified Files: >>> ssh.in >>> >>> Log Message: >>> bug952: avoid to freeze for a long time >>> =================================================================== >>> RCS file: >>> /home/cvs/linux-ha/linux-ha/lib/plugins/stonith/external/ssh.in,v >>> retrieving revision 1.7 >>> retrieving revision 1.8 >>> diff -u -3 -r1.7 -r1.8 >>> --- ssh.in 17 Nov 2005 05:32:31 -0000 1.7 >>> +++ ssh.in 30 Nov 2005 02:28:37 -0000 1.8 >>> @@ -41,7 +41,7 @@ >>> for j in 1 2 3 >>> do >>> if >>> - ping -w0.5 -c1 "$1" >/dev/null 2>&1 >>> + ping -w1 -c1 "$1" >/dev/null 2>&1 >>> then >>> return 1 >>> fi >>> @@ -97,7 +97,7 @@ >>> for h in $hostlist >>> do >>> if >>> - host $h 2>&1 | grep "not found:" >>> + ping -w1 -c1 "$h" 2>&1 | grep "unknown host" > > > But, this change is in error. > > You should not fail to verify the parameters just because the host is > down. That's what the code originally did - and it's wrong. Ping is > the wrong command to issue in this case. On the other hand, this is > probably exactly what caused the problem in my site - since they aren't > in DNS, but only in /etc/hosts. > > So, the right thing to do is write a function - maybe called checkhost() > which looks in /etc/hosts, and if it's not there, then use host as it > originally did.
I think it would be better to write a small c programme that exposes gethostbyname as a shell command. This would honour the previling nsswitch.conf and let libc worry about the details. Something like the code below. Sorry its a bit over engineered, I pieced it from code I had lying around the house. -- Horms /********************************************************************** * gethostbyname.c December 2005 * Horms [EMAIL PROTECTED] * * gethostbyname * Expose gethostbyname as a shell command * Copyright (C) 1999-2005 Horms and others * * Based on code from libvanessa_socket and libvanessa_logger * Copyright (C) 1999-2005 Horms and others * http://www.vergenet.net/linux/vanessa/ * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public License * as published by the Free Software Foundation; either version 2 of * the License, or (at your option) any later version. * * This library is distributed in the hope that it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this library; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA * 02111-1307 USA * **********************************************************************/ #include <sys/types.h> #include <netdb.h> #include <errno.h> #include <string.h> #include <stdio.h> #include <stdlib.h> #include <sys/socket.h> #include <netinet/in.h> #include <arpa/inet.h> #define NAME "gethostbyname" #define VERSION "0.9.0" #define COPYRIGHT "Copyright (C) 1999-2005 by Horms and others" #define WARRANTY \ NAME " comes with ABSOLUTELY NO WARRANTY. This is free software, and you\n" \ "are welcome to redistribute it under certain conditions. See the GNU\n" \ "Lesser General Public Licence for details." static char strherror_str[34]; /********************************************************************** * strherror_r * Returns a string describing the error code present in errnum * according to the errors for h_errno which is set by gethostbyname(3) * gethostbyaddr(3) and others. Analagous to strerror_r(3). * pre: errnum: Error to show as a string * buf: buffer to write error string to * n: length of buf in bytes * post: on success error string is written to buf * on invalid input errno is set to -EINVAL * if buf is too short then errno is set to -ERANGE * return: 0 on success * -1 on error **********************************************************************/ static int strherror_r(int errnum, char *buf, size_t n) { size_t len; char *str; switch(errnum) { case HOST_NOT_FOUND: str = "Unknown host"; break; case NO_ADDRESS: /* case NO_DATA: */ str = "Host has no address"; break; case NO_RECOVERY: str = "Non-recoverable name server error"; break; case TRY_AGAIN: str = "Transient lookup error"; break; default: errno = -EINVAL; return -1; } len = strlen(str) + 1; if(len > n) { errno = -ERANGE; return -1; } memcpy(buf, str, len); return 0; } /********************************************************************** * strherror * Returns a string describing the error code present in errnum * according to the errors for h_errno which is set by gethostbyname(3) * gethostbyaddr(3) and others. Analagous to strerror_r(3). * pre: errnum: Error to show as a string * post: none on success * on invalud input errno is set to -EINVAL * if buf is too short then errno is set to -ERANGE * return: error string for errnum on success * error string for newly set errno on error **********************************************************************/ static char * strherror(int errnum) { int status; status = strherror_r(errnum, strherror_str, sizeof(strherror_str)); if (status < 0) { return strerror(errno); } return strherror_str; } /********************************************************************** * host_in_addr * A host is given as a string either as a host name or IP address * as a dotted quad. The host is used to seed an in_addr structure * with a binary representation of the IP address of the host * in network byte order. * pre: host: hostname or IP address * If NULL then INADDR_ANY will be converted to network * byte order and used as the address. * in: pointer to an in_addr structure. * post: none * return: 0 on success * -1 on error **********************************************************************/ static int host_in_addr(const char *host, struct in_addr *in) { struct hostent *hp; extern int h_errno; if (host == NULL) { in->s_addr = htonl(INADDR_ANY); return 0; } if ((hp = gethostbyname(host)) == NULL) { fprintf(stderr, "host_in_addr %s: %s\n", host, strherror(h_errno)); return -1; } memcpy(in, hp->h_addr, hp->h_length); return 0; } /* Stuff below this comment may be relicenced GPL after contacting * Horms <[EMAIL PROTECTED]/ * Stuff above this line is part of existing LGPL libraries and * should be broken out into a LGPL library if GPL licencing * is desired. */ static void version(FILE *fd) { fprintf(fd, "%s version %s\n%s\n\n%s\n", NAME, VERSION, COPYRIGHT, WARRANTY); } static void usage(int exit_status) { FILE *fd; fd = exit_status ? stderr : stdout; version(fd); fprintf(fd, "\n" "%s converts a hostname to an ip address using libc's " "gethostbyname\n" "\n" "Usage: %s [OPTIONS] HOST\n" "\n" "Options:\n" " -h|--help: display this message and exit\n" " -v|--version: version information and exit\n" "\n", NAME, NAME); exit(exit_status); } int main(int argc, char **argv) { int i; const char *hostname = NULL; struct in_addr addr; for (i = 1; i < argc; i++) { if (!strcmp(argv[i], "--help") || !strcmp(argv[i], "-h")) { usage(0); } if (!strcmp(argv[i], "--version") || !strcmp(argv[i], "-v")) { version(stdout); return 0; } if (hostname) { usage(1); } hostname = argv[i]; } if (!hostname) { usage(1); } if (host_in_addr(hostname, &addr) < 0) { return -1; } printf("%s\n", inet_ntoa(addr)); return 0; } _______________________________________________________ Linux-HA-Dev: Linux-HA-Dev@lists.linux-ha.org http://lists.linux-ha.org/mailman/listinfo/linux-ha-dev Home Page: http://linux-ha.org/
