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[/] [openrisc/] [trunk/] [gnu-src/] [newlib-1.18.0/] [newlib/] [libc/] [sys/] [linux/] [gethostid.c] - Rev 262
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/* Copyright (C) 1995,1996,1998,1999,2000,2001 Free Software Foundation, Inc. This file is part of the GNU C Library. The GNU C 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 2.1 of the License, or (at your option) any later version. The GNU C 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 the GNU C Library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA. */ #include <alloca.h> #include <errno.h> #include <fcntl.h> #include <unistd.h> #include <netdb.h> #define HOSTIDFILE "/etc/hostid" #define OLD_HOSTIDFILE "/etc/hostid" #if !defined(_ELIX_LEVEL) || _ELIX_LEVEL >= 2 # define OPEN __open64 #else # define OPEN __open #endif #ifdef SET_PROCEDURE int sethostid (id) long int id; { int fd; ssize_t written; /* Open file for writing. Everybody is allowed to read this file. */ fd = OPEN (HOSTIDFILE, O_CREAT|O_WRONLY|O_TRUNC, 0644); if (fd < 0) return -1; written = __write (fd, &id, sizeof (id)); __close (fd); return written != sizeof (id) ? -1 : 0; } #else # include <string.h> # include <sys/param.h> # include <netdb.h> # include <netinet/in.h> long int gethostid () { char hostname[MAXHOSTNAMELEN + 1]; size_t buflen; char *buffer; struct hostent hostbuf, *hp; unsigned long int id; struct in_addr in; int herr; int fd; /* First try to get the ID from a former invocation of sethostid. */ fd = OPEN (HOSTIDFILE, O_RDONLY); if (fd >= 0) { ssize_t n = __read (fd, &id, sizeof (id)); __close (fd); if (n == sizeof (id)) return id; } /* Getting from the file was not successful. An intelligent guess for a unique number of a host is its IP address. Return this. */ if (__gethostname (hostname, MAXHOSTNAMELEN) < 0 || hostname[0] == '\0') /* This also fails. Return and arbitrary value. */ return 0; buflen = 1024; buffer = alloca (buflen); /* To get the IP address we need to know the host name. */ while (__gethostbyname_r (hostname, &hostbuf, buffer, buflen, &hp, &herr) != 0 || hp == NULL) if (herr != NETDB_INTERNAL || errno != ERANGE) return 0; else { /* Enlarge buffer. */ buflen *= 2; buffer = alloca (buflen); } in.s_addr = 0; memcpy (&in, hp->h_addr, (int) sizeof (in) < hp->h_length ? sizeof (in) : hp->h_length); /* For the return value to be not exactly the IP address we do some bit fiddling. */ return in.s_addr << 16 | in.s_addr >> 16; } #endif
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