1246074Sgabor/*- 2246074Sgabor * Copyright (C) 1990 Free Software Foundation, Inc. 3246074Sgabor * 4246074Sgabor * This program is free software; you can redistribute it and/or modify it 5246074Sgabor * without restriction. 6246074Sgabor * 7246074Sgabor * This program is distributed in the hope that it will be useful, but WITHOUT 8246074Sgabor * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 9246074Sgabor * FITNESS FOR A PARTICULAR PURPOSE. 10246074Sgabor * 11246074Sgabor * backupfile.c -- make Emacs style backup file names 12246074Sgabor * 13246074Sgabor * David MacKenzie <djm@ai.mit.edu>. Some algorithms adapted from GNU Emacs. 14246074Sgabor * 15246091Sdelphij * $OpenBSD: backupfile.c,v 1.20 2009/10/27 23:59:41 deraadt Exp $ 16246091Sdelphij * $FreeBSD$ 17246074Sgabor */ 18246074Sgabor 19246074Sgabor#include <ctype.h> 20246074Sgabor#include <dirent.h> 21246074Sgabor#include <libgen.h> 22246074Sgabor#include <stdio.h> 23246074Sgabor#include <stdlib.h> 24246074Sgabor#include <string.h> 25246074Sgabor#include <unistd.h> 26246074Sgabor 27246074Sgabor#include "backupfile.h" 28246074Sgabor 29246074Sgabor 30246074Sgabor#define ISDIGIT(c) (isascii ((unsigned char)c) && isdigit ((unsigned char)c)) 31246074Sgabor 32246074Sgabor/* Which type of backup file names are generated. */ 33246074Sgaborenum backup_type backup_type = none; 34246074Sgabor 35246074Sgabor/* 36246074Sgabor * The extension added to file names to produce a simple (as opposed to 37246074Sgabor * numbered) backup file name. 38246074Sgabor */ 39246074Sgaborconst char *simple_backup_suffix = "~"; 40246074Sgabor 41246074Sgaborstatic char *concat(const char *, const char *); 42246074Sgaborstatic char *make_version_name(const char *, int); 43246074Sgaborstatic int max_backup_version(const char *, const char *); 44246074Sgaborstatic int version_number(const char *, const char *, size_t); 45246074Sgaborstatic int argmatch(const char *, const char **); 46246074Sgaborstatic void invalid_arg(const char *, const char *, int); 47246074Sgabor 48246074Sgabor/* 49246074Sgabor * Return the name of the new backup file for file FILE, allocated with 50246074Sgabor * malloc. Return 0 if out of memory. FILE must not end with a '/' unless it 51246074Sgabor * is the root directory. Do not call this function if backup_type == none. 52246074Sgabor */ 53246074Sgaborchar * 54246074Sgaborfind_backup_file_name(const char *file) 55246074Sgabor{ 56246074Sgabor char *dir, *base_versions, *tmp_file; 57246074Sgabor int highest_backup; 58246074Sgabor 59246074Sgabor if (backup_type == simple) 60246074Sgabor return concat(file, simple_backup_suffix); 61246074Sgabor tmp_file = strdup(file); 62246074Sgabor if (tmp_file == NULL) 63246074Sgabor return NULL; 64246074Sgabor base_versions = concat(basename(tmp_file), ".~"); 65246074Sgabor free(tmp_file); 66246074Sgabor if (base_versions == NULL) 67246074Sgabor return NULL; 68246074Sgabor tmp_file = strdup(file); 69246074Sgabor if (tmp_file == NULL) { 70246074Sgabor free(base_versions); 71246074Sgabor return NULL; 72246074Sgabor } 73246074Sgabor dir = dirname(tmp_file); 74246074Sgabor if (dir == NULL) { 75246074Sgabor free(base_versions); 76246074Sgabor free(tmp_file); 77246074Sgabor return NULL; 78246074Sgabor } 79246074Sgabor highest_backup = max_backup_version(base_versions, dir); 80246074Sgabor free(base_versions); 81246074Sgabor free(tmp_file); 82246074Sgabor if (backup_type == numbered_existing && highest_backup == 0) 83246074Sgabor return concat(file, simple_backup_suffix); 84246074Sgabor return make_version_name(file, highest_backup + 1); 85246074Sgabor} 86246074Sgabor 87246074Sgabor/* 88246074Sgabor * Return the number of the highest-numbered backup file for file FILE in 89246074Sgabor * directory DIR. If there are no numbered backups of FILE in DIR, or an 90246074Sgabor * error occurs reading DIR, return 0. FILE should already have ".~" appended 91246074Sgabor * to it. 92246074Sgabor */ 93246074Sgaborstatic int 94246074Sgabormax_backup_version(const char *file, const char *dir) 95246074Sgabor{ 96246074Sgabor DIR *dirp; 97246074Sgabor struct dirent *dp; 98246074Sgabor int highest_version, this_version; 99246074Sgabor size_t file_name_length; 100246074Sgabor 101246074Sgabor dirp = opendir(dir); 102246074Sgabor if (dirp == NULL) 103246074Sgabor return 0; 104246074Sgabor 105246074Sgabor highest_version = 0; 106246074Sgabor file_name_length = strlen(file); 107246074Sgabor 108246074Sgabor while ((dp = readdir(dirp)) != NULL) { 109246074Sgabor if (dp->d_namlen <= file_name_length) 110246074Sgabor continue; 111246074Sgabor 112246074Sgabor this_version = version_number(file, dp->d_name, file_name_length); 113246074Sgabor if (this_version > highest_version) 114246074Sgabor highest_version = this_version; 115246074Sgabor } 116246074Sgabor closedir(dirp); 117246074Sgabor return highest_version; 118246074Sgabor} 119246074Sgabor 120246074Sgabor/* 121246074Sgabor * Return a string, allocated with malloc, containing "FILE.~VERSION~". 122246074Sgabor * Return 0 if out of memory. 123246074Sgabor */ 124246074Sgaborstatic char * 125246074Sgabormake_version_name(const char *file, int version) 126246074Sgabor{ 127246074Sgabor char *backup_name; 128246074Sgabor 129246074Sgabor if (asprintf(&backup_name, "%s.~%d~", file, version) == -1) 130246074Sgabor return NULL; 131246074Sgabor return backup_name; 132246074Sgabor} 133246074Sgabor 134246074Sgabor/* 135246074Sgabor * If BACKUP is a numbered backup of BASE, return its version number; 136246074Sgabor * otherwise return 0. BASE_LENGTH is the length of BASE. BASE should 137246074Sgabor * already have ".~" appended to it. 138246074Sgabor */ 139246074Sgaborstatic int 140246074Sgaborversion_number(const char *base, const char *backup, size_t base_length) 141246074Sgabor{ 142246074Sgabor int version; 143246074Sgabor const char *p; 144246074Sgabor 145246074Sgabor version = 0; 146246074Sgabor if (!strncmp(base, backup, base_length) && ISDIGIT(backup[base_length])) { 147246074Sgabor for (p = &backup[base_length]; ISDIGIT(*p); ++p) 148246074Sgabor version = version * 10 + *p - '0'; 149246074Sgabor if (p[0] != '~' || p[1]) 150246074Sgabor version = 0; 151246074Sgabor } 152246074Sgabor return version; 153246074Sgabor} 154246074Sgabor 155246074Sgabor/* 156246074Sgabor * Return the newly-allocated concatenation of STR1 and STR2. If out of 157246074Sgabor * memory, return 0. 158246074Sgabor */ 159246074Sgaborstatic char * 160246074Sgaborconcat(const char *str1, const char *str2) 161246074Sgabor{ 162246074Sgabor char *newstr; 163246074Sgabor 164246074Sgabor if (asprintf(&newstr, "%s%s", str1, str2) == -1) 165246074Sgabor return NULL; 166246074Sgabor return newstr; 167246074Sgabor} 168246074Sgabor 169246074Sgabor/* 170246074Sgabor * If ARG is an unambiguous match for an element of the null-terminated array 171246074Sgabor * OPTLIST, return the index in OPTLIST of the matched element, else -1 if it 172246074Sgabor * does not match any element or -2 if it is ambiguous (is a prefix of more 173246074Sgabor * than one element). 174246074Sgabor */ 175246074Sgaborstatic int 176246074Sgaborargmatch(const char *arg, const char **optlist) 177246074Sgabor{ 178246074Sgabor int i; /* Temporary index in OPTLIST. */ 179246074Sgabor size_t arglen; /* Length of ARG. */ 180246074Sgabor int matchind = -1; /* Index of first nonexact match. */ 181246074Sgabor int ambiguous = 0; /* If nonzero, multiple nonexact match(es). */ 182246074Sgabor 183246074Sgabor arglen = strlen(arg); 184246074Sgabor 185246074Sgabor /* Test all elements for either exact match or abbreviated matches. */ 186246074Sgabor for (i = 0; optlist[i]; i++) { 187246074Sgabor if (!strncmp(optlist[i], arg, arglen)) { 188246074Sgabor if (strlen(optlist[i]) == arglen) 189246074Sgabor /* Exact match found. */ 190246074Sgabor return i; 191246074Sgabor else if (matchind == -1) 192246074Sgabor /* First nonexact match found. */ 193246074Sgabor matchind = i; 194246074Sgabor else 195246074Sgabor /* Second nonexact match found. */ 196246074Sgabor ambiguous = 1; 197246074Sgabor } 198246074Sgabor } 199246074Sgabor if (ambiguous) 200246074Sgabor return -2; 201246074Sgabor else 202246074Sgabor return matchind; 203246074Sgabor} 204246074Sgabor 205246074Sgabor/* 206246074Sgabor * Error reporting for argmatch. KIND is a description of the type of entity 207246074Sgabor * that was being matched. VALUE is the invalid value that was given. PROBLEM 208246074Sgabor * is the return value from argmatch. 209246074Sgabor */ 210246074Sgaborstatic void 211246074Sgaborinvalid_arg(const char *kind, const char *value, int problem) 212246074Sgabor{ 213246074Sgabor fprintf(stderr, "patch: "); 214246074Sgabor if (problem == -1) 215246074Sgabor fprintf(stderr, "invalid"); 216246074Sgabor else /* Assume -2. */ 217246074Sgabor fprintf(stderr, "ambiguous"); 218246074Sgabor fprintf(stderr, " %s `%s'\n", kind, value); 219246074Sgabor} 220246074Sgabor 221246074Sgaborstatic const char *backup_args[] = { 222246074Sgabor "never", "simple", "nil", "existing", "t", "numbered", 0 223246074Sgabor}; 224246074Sgabor 225246074Sgaborstatic enum backup_type backup_types[] = { 226246074Sgabor simple, simple, numbered_existing, 227246074Sgabor numbered_existing, numbered, numbered 228246074Sgabor}; 229246074Sgabor 230246074Sgabor/* 231246074Sgabor * Return the type of backup indicated by VERSION. Unique abbreviations are 232246074Sgabor * accepted. 233246074Sgabor */ 234246074Sgaborenum backup_type 235246074Sgaborget_version(const char *version) 236246074Sgabor{ 237246074Sgabor int i; 238246074Sgabor 239246074Sgabor if (version == NULL || *version == '\0') 240246074Sgabor return numbered_existing; 241246074Sgabor i = argmatch(version, backup_args); 242246074Sgabor if (i >= 0) 243246074Sgabor return backup_types[i]; 244246074Sgabor invalid_arg("version control type", version, i); 245246074Sgabor exit(2); 246246074Sgabor} 247