#define __FORCE_GLIBC
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#define __FORCE_GLIBC
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#include <features.h>
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#include <features.h>
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#include <stdio.h>
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#include <stdio.h>
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#include <string.h>
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#include <string.h>
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#include <errno.h>
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#include <errno.h>
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#include <sys/param.h>
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#include <sys/param.h>
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#include <netinet/in.h>
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#include <netinet/in.h>
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#include <netdb.h>
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#include <netdb.h>
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#include <fcntl.h>
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#include <fcntl.h>
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#include <unistd.h>
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#include <unistd.h>
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#define HOSTID "/etc/hostid"
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#define HOSTID "/etc/hostid"
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int sethostid(long int new_id)
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int sethostid(long int new_id)
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{
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{
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int fd;
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int fd;
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int ret;
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int ret;
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if (geteuid() || getuid()) return __set_errno(EPERM);
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if (geteuid() || getuid()) return __set_errno(EPERM);
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if ((fd=open(HOSTID,O_CREAT|O_WRONLY,0644))<0) return -1;
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if ((fd=open(HOSTID,O_CREAT|O_WRONLY,0644))<0) return -1;
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ret = write(fd,(void *)&new_id,sizeof(new_id)) == sizeof(new_id)
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ret = write(fd,(void *)&new_id,sizeof(new_id)) == sizeof(new_id)
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? 0 : -1;
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? 0 : -1;
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close (fd);
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close (fd);
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return ret;
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return ret;
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}
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}
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long int gethostid(void)
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long int gethostid(void)
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{
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{
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char host[MAXHOSTNAMELEN + 1];
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char host[MAXHOSTNAMELEN + 1];
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int fd, id;
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int fd, id;
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/* If hostid was already set the we can return that value.
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/* If hostid was already set the we can return that value.
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* It is not an error if we cannot read this file. It is not even an
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* It is not an error if we cannot read this file. It is not even an
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* error if we cannot read all the bytes, we just carry on trying...
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* error if we cannot read all the bytes, we just carry on trying...
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*/
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*/
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if ((fd=open(HOSTID,O_RDONLY))>=0 && read(fd,(void *)&id,sizeof(id)))
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if ((fd=open(HOSTID,O_RDONLY))>=0 && read(fd,(void *)&id,sizeof(id)))
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{
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{
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close (fd);
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close (fd);
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return id;
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return id;
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}
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}
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if (fd >= 0) close (fd);
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if (fd >= 0) close (fd);
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/* Try some methods of returning a unique 32 bit id. Clearly IP
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/* Try some methods of returning a unique 32 bit id. Clearly IP
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* numbers, if on the internet, will have a unique address. If they
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* numbers, if on the internet, will have a unique address. If they
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* are not on the internet then we can return 0 which means they should
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* are not on the internet then we can return 0 which means they should
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* really set this number via a sethostid() call. If their hostname
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* really set this number via a sethostid() call. If their hostname
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* returns the loopback number (i.e. if they have put their hostname
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* returns the loopback number (i.e. if they have put their hostname
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* in the /etc/hosts file with 127.0.0.1) then all such hosts will
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* in the /etc/hosts file with 127.0.0.1) then all such hosts will
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* have a non-unique hostid, but it doesn't matter anyway and
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* have a non-unique hostid, but it doesn't matter anyway and
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* gethostid() will return a non zero number without the need for
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* gethostid() will return a non zero number without the need for
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* setting one anyway.
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* setting one anyway.
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* Mitch
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* Mitch
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*/
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*/
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if (gethostname(host,MAXHOSTNAMELEN)>=0 && *host) {
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if (gethostname(host,MAXHOSTNAMELEN)>=0 && *host) {
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struct hostent *hp;
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struct hostent *hp;
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struct in_addr in;
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struct in_addr in;
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if ((hp = gethostbyname(host)) == (struct hostent *)NULL)
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if ((hp = gethostbyname(host)) == (struct hostent *)NULL)
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/* This is not a error if we get here, as all it means is that
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/* This is not a error if we get here, as all it means is that
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* this host is not on a network and/or they have not
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* this host is not on a network and/or they have not
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* configured their network properly. So we return the unset
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* configured their network properly. So we return the unset
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* hostid which should be 0, meaning that they should set it !!
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* hostid which should be 0, meaning that they should set it !!
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*/
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*/
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return 0;
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return 0;
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else {
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else {
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memcpy((char *) &in, (char *) hp->h_addr, hp->h_length);
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memcpy((char *) &in, (char *) hp->h_addr, hp->h_length);
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/* Just so it doesn't look exactly like the IP addr */
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/* Just so it doesn't look exactly like the IP addr */
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return(in.s_addr<<16|in.s_addr>>16);
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return(in.s_addr<<16|in.s_addr>>16);
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}
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}
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}
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}
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else return 0;
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else return 0;
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}
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}
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