264 lines
6.6 KiB
C
264 lines
6.6 KiB
C
/*
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* $OpenBSD: backupfile.c,v 1.19 2006/03/11 19:41:30 otto Exp $
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* $DragonFly: src/usr.bin/patch/backupfile.c,v 1.5 2008/08/11 00:05:06 joerg Exp $
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* $NetBSD: backupfile.c,v 1.14 2008/09/19 18:33:34 joerg Exp $
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*/
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/*
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* backupfile.c -- make Emacs style backup file names
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*
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* Copyright (C) 1990 Free 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 <sys/cdefs.h>
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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 ((unsigned char)c) && isdigit ((unsigned char)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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const 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, *tmp_file;
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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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tmp_file = strdup(file);
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if (tmp_file == NULL)
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return NULL;
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base_versions = concat(basename(tmp_file), ".~");
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free(tmp_file);
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if (base_versions == NULL)
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return NULL;
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tmp_file = strdup(file);
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if (tmp_file == NULL) {
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free(base_versions);
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return NULL;
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}
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dir = dirname(tmp_file);
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if (dir == NULL) {
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free(base_versions);
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free(tmp_file);
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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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free(tmp_file);
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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 (strlen(dp->d_name) <= 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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int len = strlen(file)+20;
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if(!(backup_name = malloc(len)))
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return NULL;
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if (snprintf(backup_name, len, "%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) && ISDIGIT(backup[base_length])) {
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for (p = &backup[base_length]; ISDIGIT(*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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int len = strlen(str1) + strlen(str2) + 1;
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if(!(newstr = malloc(strlen(str1) + strlen(str2) + 1)))
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return NULL;
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if (snprintf(newstr, len, "%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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}
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