64 lines
2.1 KiB
C
64 lines
2.1 KiB
C
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/* xgetaname-impl.c -- common implementation of xgethostname and xgetdomainname
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Copyright (C) 1992, 1996, 2000-2001, 2003-2006, 2009-2022 Free Software
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Foundation, Inc.
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <https://www.gnu.org/licenses/>. */
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/* written by Jim Meyering and Paul Eggert */
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#include <stdlib.h>
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#include <errno.h>
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#include <string.h>
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#include <unistd.h>
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#include "xalloc.h"
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/* Return the current host or domain name in malloc'd storage.
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If malloc fails, exit.
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Upon any other failure, return NULL and set errno. */
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char *
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XGETANAME (void)
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{
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char buf[100];
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idx_t size = sizeof buf;
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char *name = buf;
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char *alloc = NULL;
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while (1)
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{
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/* Use SIZE_1 here rather than SIZE to work around the bug in
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SunOS 5.5's gethostname whereby it NUL-terminates HOSTNAME
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even when the name is as long as the supplied buffer. */
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idx_t size_1 = size - 1;
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name[size_1] = '\0';
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errno = 0;
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if (GETANAME (name, size_1) == 0)
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{
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/* Check whether the name was possibly truncated; POSIX does not
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specify whether a truncated name is null-terminated. */
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idx_t actual_size = strlen (name) + 1;
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if (actual_size < size_1)
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return alloc ? alloc : ximemdup (name, actual_size);
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errno = 0;
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}
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free (alloc);
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if (errno != 0 && errno != ENAMETOOLONG && errno != EINVAL
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/* macOS/Darwin does this when SIZE_1 is too small. */
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&& errno != ENOMEM)
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return NULL;
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name = alloc = xpalloc (NULL, &size, 1, -1, 1);
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}
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}
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