1 /* 2 * $OpenBSD: backupfile.c,v 1.19 2006/03/11 19:41:30 otto Exp $ 3 * $DragonFly: src/usr.bin/patch/backupfile.c,v 1.4 2007/09/29 23:11:10 swildner Exp $ 4 */ 5 6 /* 7 * backupfile.c -- make Emacs style backup file names Copyright (C) 1990 Free 8 * Software Foundation, Inc. 9 * 10 * This program is free software; you can redistribute it and/or modify it 11 * without restriction. 12 * 13 * This program is distributed in the hope that it will be useful, but WITHOUT 14 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 15 * FITNESS FOR A PARTICULAR PURPOSE. 16 */ 17 18 /* 19 * David MacKenzie <djm@ai.mit.edu>. Some algorithms adapted from GNU Emacs. 20 */ 21 22 #include <ctype.h> 23 #include <dirent.h> 24 #include <libgen.h> 25 #include <stdio.h> 26 #include <stdlib.h> 27 #include <string.h> 28 #include <unistd.h> 29 30 #include "backupfile.h" 31 32 33 #define ISDIGIT(c) (isascii ((unsigned char)c) && isdigit ((unsigned char)c)) 34 35 /* Which type of backup file names are generated. */ 36 enum backup_type backup_type = none; 37 38 /* 39 * The extension added to file names to produce a simple (as opposed to 40 * numbered) backup file name. 41 */ 42 const char *simple_backup_suffix = "~"; 43 44 static char *concat(const char *, const char *); 45 static char *make_version_name(const char *, int); 46 static int max_backup_version(const char *, const char *); 47 static int version_number(const char *, const char *, size_t); 48 static int argmatch(const char *, const char **); 49 static void invalid_arg(const char *, const char *, int); 50 51 /* 52 * Return the name of the new backup file for file FILE, allocated with 53 * malloc. Return 0 if out of memory. FILE must not end with a '/' unless it 54 * is the root directory. Do not call this function if backup_type == none. 55 */ 56 char * 57 find_backup_file_name(const char *file) 58 { 59 char *dir, *base_versions, *tmp_file; 60 int highest_backup; 61 62 if (backup_type == simple) 63 return concat(file, simple_backup_suffix); 64 tmp_file = strdup(file); 65 if (tmp_file == NULL) 66 return NULL; 67 base_versions = concat(basename(tmp_file), ".~"); 68 free(tmp_file); 69 if (base_versions == NULL) 70 return NULL; 71 tmp_file = strdup(file); 72 if (tmp_file == NULL) { 73 free(base_versions); 74 return NULL; 75 } 76 dir = dirname(tmp_file); 77 if (dir == NULL) { 78 free(base_versions); 79 free(tmp_file); 80 return NULL; 81 } 82 highest_backup = max_backup_version(base_versions, dir); 83 free(base_versions); 84 free(tmp_file); 85 if (backup_type == numbered_existing && highest_backup == 0) 86 return concat(file, simple_backup_suffix); 87 return make_version_name(file, highest_backup + 1); 88 } 89 90 /* 91 * Return the number of the highest-numbered backup file for file FILE in 92 * directory DIR. If there are no numbered backups of FILE in DIR, or an 93 * error occurs reading DIR, return 0. FILE should already have ".~" appended 94 * to it. 95 */ 96 static int 97 max_backup_version(const char *file, const char *dir) 98 { 99 DIR *dirp; 100 struct dirent *dp; 101 int highest_version, this_version; 102 size_t file_name_length; 103 104 dirp = opendir(dir); 105 if (dirp == NULL) 106 return 0; 107 108 highest_version = 0; 109 file_name_length = strlen(file); 110 111 while ((dp = readdir(dirp)) != NULL) { 112 if (dp->d_namlen <= file_name_length) 113 continue; 114 115 this_version = version_number(file, dp->d_name, file_name_length); 116 if (this_version > highest_version) 117 highest_version = this_version; 118 } 119 closedir(dirp); 120 return highest_version; 121 } 122 123 /* 124 * Return a string, allocated with malloc, containing "FILE.~VERSION~". 125 * Return 0 if out of memory. 126 */ 127 static char * 128 make_version_name(const char *file, int version) 129 { 130 char *backup_name; 131 132 if (asprintf(&backup_name, "%s.~%d~", file, version) == -1) 133 return NULL; 134 return backup_name; 135 } 136 137 /* 138 * If BACKUP is a numbered backup of BASE, return its version number; 139 * otherwise return 0. BASE_LENGTH is the length of BASE. BASE should 140 * already have ".~" appended to it. 141 */ 142 static int 143 version_number(const char *base, const char *backup, size_t base_length) 144 { 145 int version; 146 const char *p; 147 148 version = 0; 149 if (!strncmp(base, backup, base_length) && ISDIGIT(backup[base_length])) { 150 for (p = &backup[base_length]; ISDIGIT(*p); ++p) 151 version = version * 10 + *p - '0'; 152 if (p[0] != '~' || p[1]) 153 version = 0; 154 } 155 return version; 156 } 157 158 /* 159 * Return the newly-allocated concatenation of STR1 and STR2. If out of 160 * memory, return 0. 161 */ 162 static char * 163 concat(const char *str1, const char *str2) 164 { 165 char *newstr; 166 167 if (asprintf(&newstr, "%s%s", str1, str2) == -1) 168 return NULL; 169 return newstr; 170 } 171 172 /* 173 * If ARG is an unambiguous match for an element of the null-terminated array 174 * OPTLIST, return the index in OPTLIST of the matched element, else -1 if it 175 * does not match any element or -2 if it is ambiguous (is a prefix of more 176 * than one element). 177 */ 178 static int 179 argmatch(const char *arg, const char **optlist) 180 { 181 int i; /* Temporary index in OPTLIST. */ 182 size_t arglen; /* Length of ARG. */ 183 int matchind = -1; /* Index of first nonexact match. */ 184 int ambiguous = 0; /* If nonzero, multiple nonexact match(es). */ 185 186 arglen = strlen(arg); 187 188 /* Test all elements for either exact match or abbreviated matches. */ 189 for (i = 0; optlist[i]; i++) { 190 if (!strncmp(optlist[i], arg, arglen)) { 191 if (strlen(optlist[i]) == arglen) 192 /* Exact match found. */ 193 return i; 194 else if (matchind == -1) 195 /* First nonexact match found. */ 196 matchind = i; 197 else 198 /* Second nonexact match found. */ 199 ambiguous = 1; 200 } 201 } 202 if (ambiguous) 203 return -2; 204 else 205 return matchind; 206 } 207 208 /* 209 * Error reporting for argmatch. KIND is a description of the type of entity 210 * that was being matched. VALUE is the invalid value that was given. PROBLEM 211 * is the return value from argmatch. 212 */ 213 static void 214 invalid_arg(const char *kind, const char *value, int problem) 215 { 216 fprintf(stderr, "patch: "); 217 if (problem == -1) 218 fprintf(stderr, "invalid"); 219 else /* Assume -2. */ 220 fprintf(stderr, "ambiguous"); 221 fprintf(stderr, " %s `%s'\n", kind, value); 222 } 223 224 static const char *backup_args[] = { 225 "never", "simple", "nil", "existing", "t", "numbered", 0 226 }; 227 228 static enum backup_type backup_types[] = { 229 simple, simple, numbered_existing, 230 numbered_existing, numbered, numbered 231 }; 232 233 /* 234 * Return the type of backup indicated by VERSION. Unique abbreviations are 235 * accepted. 236 */ 237 enum backup_type 238 get_version(const char *version) 239 { 240 int i; 241 242 if (version == NULL || *version == '\0') 243 return numbered_existing; 244 i = argmatch(version, backup_args); 245 if (i >= 0) 246 return backup_types[i]; 247 invalid_arg("version control type", version, i); 248 exit(2); 249 } 250