diff options
Diffstat (limited to 'libc/inet')
| -rw-r--r-- | libc/inet/Makefile | 2 | ||||
| -rw-r--r-- | libc/inet/hostid.c | 74 |
2 files changed, 75 insertions, 1 deletions
diff --git a/libc/inet/Makefile b/libc/inet/Makefile index e5f11ee51..1e9ac365d 100644 --- a/libc/inet/Makefile +++ b/libc/inet/Makefile @@ -41,7 +41,7 @@ MOBJ3= accept.o bind.o connect.o getpeername.o getsockname.o getsockopt.o \ listen.o recv.o recvfrom.o recvmsg.o send.o sendmsg.o sendto.o \ setsockopt.o shutdown.o socket.o socketpair.o -CSRC =getservice.c getproto.c +CSRC =getservice.c getproto.c hostid.c COBJS=$(patsubst %.c,%.o, $(CSRC)) OBJS=$(MOBJ) $(MOBJ2) $(MOBJ3) $(COBJS) diff --git a/libc/inet/hostid.c b/libc/inet/hostid.c new file mode 100644 index 000000000..475eaf497 --- /dev/null +++ b/libc/inet/hostid.c @@ -0,0 +1,74 @@ +#include <stdio.h> +#include <string.h> +#include <errno.h> +#include <sys/param.h> +#include <netinet/in.h> +#include <netdb.h> +#include <fcntl.h> +#include <unistd.h> + + +#define HOSTID "/etc/hostid" + +int sethostid(long int new_id) +{ + int fd; + int ret; + + if (geteuid() || getuid()) return errno=EPERM; + if ((fd=open(HOSTID,O_CREAT|O_WRONLY,0644))<0) return -1; + ret = write(fd,(void *)&new_id,sizeof(new_id)) == sizeof(new_id) + ? 0 : -1; + close (fd); + return ret; +} + +long int gethostid(void) +{ + char host[MAXHOSTNAMELEN + 1]; + int fd, id; + + /* If hostid was already set the we can return that value. + * It is not an error if we cannot read this file. It is not even an + * error if we cannot read all the bytes, we just carry on trying... + */ + if ((fd=open(HOSTID,O_RDONLY))>=0 && read(fd,(void *)&id,sizeof(id))) + { + close (fd); + return id; + } + if (fd >= 0) close (fd); + + /* Try some methods of returning a unique 32 bit id. Clearly IP + * numbers, if on the internet, will have a unique address. If they + * are not on the internet then we can return 0 which means they should + * really set this number via a sethostid() call. If their hostname + * returns the loopback number (i.e. if they have put their hostname + * in the /etc/hosts file with 127.0.0.1) then all such hosts will + * have a non-unique hostid, but it doesn't matter anyway and + * gethostid() will return a non zero number without the need for + * setting one anyway. + * Mitch + */ + if (gethostname(host,MAXHOSTNAMELEN)>=0 && *host) { + struct hostent *hp; + struct in_addr in; + + if ((hp = gethostbyname(host)) == (struct hostent *)NULL) + + /* This is not a error if we get here, as all it means is that + * this host is not on a network and/or they have not + * configured their network properly. So we return the unset + * hostid which should be 0, meaning that they should set it !! + */ + return 0; + else { + memcpy((char *) &in, (char *) hp->h_addr, hp->h_length); + + /* Just so it doesn't look exactly like the IP addr */ + return(in.s_addr<<16|in.s_addr>>16); + } + } + else return 0; + +} |