GCC Code Coverage Report
Directory: ./ Exec Total Coverage
File: usr.bin/patch/backupfile.c Lines: 27 66 40.9 %
Date: 2017-11-13 Branches: 12 52 23.1 %

Line Branch Exec Source
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/*	$OpenBSD: backupfile.c,v 1.21 2013/11/26 13:19:07 deraadt Exp $	*/
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/*
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 * backupfile.c -- make Emacs style backup file names Copyright (C) 1990 Free
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 * Software Foundation, Inc.
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 *
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 * This program is free software; you can redistribute it and/or modify it
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 * without restriction.
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 *
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 * This program is distributed in the hope that it will be useful, but WITHOUT
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 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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 * FITNESS FOR A PARTICULAR PURPOSE.
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 */
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/*
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 * David MacKenzie <djm@ai.mit.edu>. Some algorithms adapted from GNU Emacs.
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 */
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#include <ctype.h>
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#include <dirent.h>
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#include <libgen.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include "backupfile.h"
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#define ISDIGIT(c) (isascii (c) && isdigit (c))
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/* Which type of backup file names are generated. */
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enum backup_type backup_type = none;
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/*
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 * The extension added to file names to produce a simple (as opposed to
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 * numbered) backup file name.
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 */
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char		*simple_backup_suffix = "~";
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static char	*concat(const char *, const char *);
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static char	*make_version_name(const char *, int);
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static int	max_backup_version(const char *, const char *);
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static int	version_number(const char *, const char *, size_t);
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static int	argmatch(const char *, const char **);
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static void	invalid_arg(const char *, const char *, int);
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/*
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 * Return the name of the new backup file for file FILE, allocated with
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 * malloc.  Return 0 if out of memory. FILE must not end with a '/' unless it
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 * is the root directory. Do not call this function if backup_type == none.
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 */
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char *
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find_backup_file_name(const char *file)
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{
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	char	*dir, *base_versions;
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	int	highest_backup;
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	if (backup_type == simple)
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		return concat(file, simple_backup_suffix);
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	base_versions = concat(basename(file), ".~");
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	if (base_versions == NULL)
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		return NULL;
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	dir = dirname(file);
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	if (dir == NULL) {
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		free(base_versions);
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		return NULL;
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	}
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	highest_backup = max_backup_version(base_versions, dir);
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	free(base_versions);
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	if (backup_type == numbered_existing && highest_backup == 0)
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		return concat(file, simple_backup_suffix);
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	return make_version_name(file, highest_backup + 1);
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}
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/*
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 * Return the number of the highest-numbered backup file for file FILE in
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 * directory DIR.  If there are no numbered backups of FILE in DIR, or an
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 * error occurs reading DIR, return 0. FILE should already have ".~" appended
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 * to it.
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 */
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static int
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max_backup_version(const char *file, const char *dir)
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{
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	DIR	*dirp;
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	struct dirent	*dp;
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	int	highest_version, this_version;
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	size_t	file_name_length;
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	dirp = opendir(dir);
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	if (dirp == NULL)
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		return 0;
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	highest_version = 0;
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	file_name_length = strlen(file);
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	while ((dp = readdir(dirp)) != NULL) {
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		if (dp->d_namlen <= file_name_length)
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			continue;
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		this_version = version_number(file, dp->d_name, file_name_length);
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		if (this_version > highest_version)
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			highest_version = this_version;
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	}
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	closedir(dirp);
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	return highest_version;
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}
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/*
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 * Return a string, allocated with malloc, containing "FILE.~VERSION~".
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 * Return 0 if out of memory.
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 */
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static char *
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make_version_name(const char *file, int version)
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{
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	char	*backup_name;
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	if (asprintf(&backup_name, "%s.~%d~", file, version) == -1)
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		return NULL;
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	return backup_name;
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}
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/*
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 * If BACKUP is a numbered backup of BASE, return its version number;
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 * otherwise return 0.  BASE_LENGTH is the length of BASE. BASE should
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 * already have ".~" appended to it.
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 */
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static int
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version_number(const char *base, const char *backup, size_t base_length)
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{
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	int		version;
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	const char	*p;
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	version = 0;
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	if (!strncmp(base, backup, base_length) &&
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	    ISDIGIT((unsigned char)backup[base_length])) {
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		for (p = &backup[base_length]; ISDIGIT((unsigned char)*p); ++p)
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			version = version * 10 + *p - '0';
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		if (p[0] != '~' || p[1])
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			version = 0;
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	}
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	return version;
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}
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/*
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 * Return the newly-allocated concatenation of STR1 and STR2. If out of
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 * memory, return 0.
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 */
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static char  *
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concat(const char *str1, const char *str2)
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{
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	char	*newstr;
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	if (asprintf(&newstr, "%s%s", str1, str2) == -1)
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		return NULL;
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	return newstr;
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}
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/*
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 * If ARG is an unambiguous match for an element of the null-terminated array
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 * OPTLIST, return the index in OPTLIST of the matched element, else -1 if it
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 * does not match any element or -2 if it is ambiguous (is a prefix of more
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 * than one element).
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 */
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static int
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argmatch(const char *arg, const char **optlist)
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{
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	int	i;	/* Temporary index in OPTLIST. */
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	size_t	arglen;	/* Length of ARG. */
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	int	matchind = -1;	/* Index of first nonexact match. */
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	int	ambiguous = 0;	/* If nonzero, multiple nonexact match(es). */
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	arglen = strlen(arg);
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	/* Test all elements for either exact match or abbreviated matches.  */
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	for (i = 0; optlist[i]; i++) {
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		if (!strncmp(optlist[i], arg, arglen)) {
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			if (strlen(optlist[i]) == arglen)
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				/* Exact match found.  */
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				return i;
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			else if (matchind == -1)
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				/* First nonexact match found.  */
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				matchind = i;
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			else
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				/* Second nonexact match found.  */
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				ambiguous = 1;
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		}
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	}
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	if (ambiguous)
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		return -2;
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	else
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		return matchind;
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}
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/*
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 * Error reporting for argmatch. KIND is a description of the type of entity
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 * that was being matched. VALUE is the invalid value that was given. PROBLEM
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 * is the return value from argmatch.
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 */
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static void
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invalid_arg(const char *kind, const char *value, int problem)
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{
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	fprintf(stderr, "patch: ");
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	if (problem == -1)
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		fprintf(stderr, "invalid");
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	else			/* Assume -2. */
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		fprintf(stderr, "ambiguous");
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	fprintf(stderr, " %s `%s'\n", kind, value);
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}
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static const char *backup_args[] = {
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	"never", "simple", "nil", "existing", "t", "numbered", 0
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};
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static enum backup_type backup_types[] = {
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	simple, simple, numbered_existing,
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	numbered_existing, numbered, numbered
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};
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/*
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 * Return the type of backup indicated by VERSION. Unique abbreviations are
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 * accepted.
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 */
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enum backup_type
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get_version(const char *version)
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{
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	int	i;
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	if (version == NULL || *version == '\0')
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		return numbered_existing;
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	i = argmatch(version, backup_args);
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	if (i >= 0)
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		return backup_types[i];
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	invalid_arg("version control type", version, i);
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	exit(2);
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}