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Diffstat (limited to 'unix/tclUnixSock.c')
-rw-r--r-- | unix/tclUnixSock.c | 100 |
1 files changed, 100 insertions, 0 deletions
diff --git a/unix/tclUnixSock.c b/unix/tclUnixSock.c new file mode 100644 index 0000000..c532993 --- /dev/null +++ b/unix/tclUnixSock.c @@ -0,0 +1,100 @@ +/* + * tclUnixSock.c -- + * + * This file contains Unix-specific socket related code. + * + * Copyright (c) 1995 Sun Microsystems, Inc. + * + * See the file "license.terms" for information on usage and redistribution + * of this file, and for a DISCLAIMER OF ALL WARRANTIES. + * + * SCCS: @(#) tclUnixSock.c 1.9 97/10/09 18:24:49 + */ + +#include "tcl.h" +#include "tclPort.h" + +/* + * There is no portable macro for the maximum length + * of host names returned by gethostbyname(). We should only + * trust SYS_NMLN if it is at least 255 + 1 bytes to comply with DNS + * host name limits. + * + * Note: SYS_NMLN is a restriction on "uname" not on gethostbyname! + * + * For example HP-UX 10.20 has SYS_NMLN == 9, while gethostbyname() + * can return a fully qualified name from DNS of up to 255 bytes. + * + * Fix suggested by Viktor Dukhovni (viktor@esm.com) + */ + +#if defined(SYS_NMLN) && SYS_NMLEN >= 256 +#define TCL_HOSTNAME_LEN SYS_NMLEN +#else +#define TCL_HOSTNAME_LEN 256 +#endif + + +/* + * The following variable holds the network name of this host. + */ + +static char hostname[TCL_HOSTNAME_LEN + 1]; +static int hostnameInited = 0; + +/* + *---------------------------------------------------------------------- + * + * Tcl_GetHostName -- + * + * Returns the name of the local host. + * + * Results: + * A string containing the network name for this machine, or + * an empty string if we can't figure out the name. The caller + * must not modify or free this string. + * + * Side effects: + * None. + * + *---------------------------------------------------------------------- + */ + +char * +Tcl_GetHostName() +{ +#ifndef NO_UNAME + struct utsname u; + struct hostent *hp; +#endif + + if (hostnameInited) { + return hostname; + } + +#ifndef NO_UNAME + (VOID *) memset((VOID *) &u, (int) 0, sizeof(struct utsname)); + if (uname(&u) > -1) { + hp = gethostbyname(u.nodename); + if (hp != NULL) { + strcpy(hostname, hp->h_name); + } else { + strcpy(hostname, u.nodename); + } + hostnameInited = 1; + return hostname; + } +#else + /* + * Uname doesn't exist; try gethostname instead. + */ + + if (gethostname(hostname, sizeof(hostname)) > -1) { + hostnameInited = 1; + return hostname; + } +#endif + + hostname[0] = 0; + return hostname; +} |