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Diffstat (limited to 'contrib/tar/lib/backupfile.c')
| -rw-r--r-- | contrib/tar/lib/backupfile.c | 278 |
1 files changed, 278 insertions, 0 deletions
diff --git a/contrib/tar/lib/backupfile.c b/contrib/tar/lib/backupfile.c new file mode 100644 index 0000000..fa5ece1 --- /dev/null +++ b/contrib/tar/lib/backupfile.c @@ -0,0 +1,278 @@ +/* backupfile.c -- make Emacs style backup file names + Copyright 1990,91,92,93,94,95,96,97,98,99,2000, 2001 Free Software + Foundation, Inc. + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 2, or (at your option) + any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; see the file COPYING. + If not, write to the Free Software Foundation, + 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ + +/* Written by David MacKenzie <djm@gnu.ai.mit.edu>. + Some algorithms adapted from GNU Emacs. */ + +#if HAVE_CONFIG_H +# include <config.h> +#endif + +#include <stdio.h> +#include <sys/types.h> +#if HAVE_STRING_H +# include <string.h> +#else +# include <strings.h> +#endif + +#if HAVE_DIRENT_H +# include <dirent.h> +# define NLENGTH(direct) strlen ((direct)->d_name) +#else +# define dirent direct +# define NLENGTH(direct) ((size_t) (direct)->d_namlen) +# if HAVE_SYS_NDIR_H +# include <sys/ndir.h> +# endif +# if HAVE_SYS_DIR_H +# include <sys/dir.h> +# endif +# if HAVE_NDIR_H +# include <ndir.h> +# endif +#endif + +#if CLOSEDIR_VOID +/* Fake a return value. */ +# define CLOSEDIR(d) (closedir (d), 0) +#else +# define CLOSEDIR(d) closedir (d) +#endif + +#if HAVE_STDLIB_H +# include <stdlib.h> +#endif + +#ifndef HAVE_DECL_GETENV +"this configure-time declaration test was not run" +#endif +#if !HAVE_DECL_GETENV +char *getenv (); +#endif + +#ifndef HAVE_DECL_MALLOC +"this configure-time declaration test was not run" +#endif +#if !HAVE_DECL_MALLOC +char *malloc (); +#endif + +#if HAVE_DIRENT_H || HAVE_NDIR_H || HAVE_SYS_DIR_H || HAVE_SYS_NDIR_H +# define HAVE_DIR 1 +#else +# define HAVE_DIR 0 +#endif + +#if HAVE_LIMITS_H +# include <limits.h> +#endif +#ifndef CHAR_BIT +# define CHAR_BIT 8 +#endif +/* Upper bound on the string length of an integer converted to string. + 302 / 1000 is ceil (log10 (2.0)). Subtract 1 for the sign bit; + add 1 for integer division truncation; add 1 more for a minus sign. */ +#define INT_STRLEN_BOUND(t) ((sizeof (t) * CHAR_BIT - 1) * 302 / 1000 + 2) + +/* ISDIGIT differs from isdigit, as follows: + - Its arg may be any int or unsigned int; it need not be an unsigned char. + - It's guaranteed to evaluate its argument exactly once. + - It's typically faster. + Posix 1003.2-1992 section 2.5.2.1 page 50 lines 1556-1558 says that + only '0' through '9' are digits. Prefer ISDIGIT to isdigit unless + it's important to use the locale's definition of `digit' even when the + host does not conform to Posix. */ +#define ISDIGIT(c) ((unsigned) (c) - '0' <= 9) + +#if D_INO_IN_DIRENT +# define REAL_DIR_ENTRY(dp) ((dp)->d_ino != 0) +#else +# define REAL_DIR_ENTRY(dp) 1 +#endif + +#include "argmatch.h" +#include "backupfile.h" +#include "dirname.h" + +/* The extension added to file names to produce a simple (as opposed + to numbered) backup file name. */ +const char *simple_backup_suffix = "~"; + +static int max_backup_version PARAMS ((const char *, const char *)); +static int version_number PARAMS ((const char *, const char *, size_t)); + +/* Return the name of the new backup file for file FILE, + allocated with malloc. Return 0 if out of memory. + FILE must not end with a '/' unless it is the root directory. + Do not call this function if backup_type == none. */ + +char * +find_backup_file_name (const char *file, enum backup_type backup_type) +{ + size_t backup_suffix_size_max; + size_t file_len = strlen (file); + size_t numbered_suffix_size_max = INT_STRLEN_BOUND (int) + 4; + char *s; + const char *suffix = simple_backup_suffix; + + /* Allow room for simple or `.~N~' backups. */ + backup_suffix_size_max = strlen (simple_backup_suffix) + 1; + if (HAVE_DIR && backup_suffix_size_max < numbered_suffix_size_max) + backup_suffix_size_max = numbered_suffix_size_max; + + s = malloc (file_len + 1 + + backup_suffix_size_max + numbered_suffix_size_max); + if (s) + { +#if HAVE_DIR + if (backup_type != simple) + { + int highest_backup; + size_t dirlen = dir_len (file); + + memcpy (s, file, dirlen); + if (dirlen == FILESYSTEM_PREFIX_LEN (file)) + s[dirlen++] = '.'; + s[dirlen] = '\0'; + highest_backup = max_backup_version (base_name (file), s); + if (! (backup_type == numbered_existing && highest_backup == 0)) + { + char *numbered_suffix = s + (file_len + backup_suffix_size_max); + sprintf (numbered_suffix, ".~%d~", highest_backup + 1); + suffix = numbered_suffix; + } + } +#endif /* HAVE_DIR */ + + strcpy (s, file); + addext (s, suffix, '~'); + } + return s; +} + +#if HAVE_DIR + +/* Return the number of the highest-numbered backup file for file + FILE in directory DIR. If there are no numbered backups + of FILE in DIR, or an error occurs reading DIR, return 0. + */ + +static int +max_backup_version (const char *file, const char *dir) +{ + DIR *dirp; + struct dirent *dp; + int highest_version; + int this_version; + size_t file_name_length; + + dirp = opendir (dir); + if (!dirp) + return 0; + + highest_version = 0; + file_name_length = base_len (file); + + while ((dp = readdir (dirp)) != 0) + { + if (!REAL_DIR_ENTRY (dp) || NLENGTH (dp) < file_name_length + 4) + continue; + + this_version = version_number (file, dp->d_name, file_name_length); + if (this_version > highest_version) + highest_version = this_version; + } + if (CLOSEDIR (dirp)) + return 0; + return highest_version; +} + +/* If BACKUP is a numbered backup of BASE, return its version number; + otherwise return 0. BASE_LENGTH is the length of BASE. + */ + +static int +version_number (const char *base, const char *backup, size_t base_length) +{ + int version; + const char *p; + + version = 0; + if (strncmp (base, backup, base_length) == 0 + && backup[base_length] == '.' + && backup[base_length + 1] == '~') + { + for (p = &backup[base_length + 2]; ISDIGIT (*p); ++p) + version = version * 10 + *p - '0'; + if (p[0] != '~' || p[1]) + version = 0; + } + return version; +} +#endif /* HAVE_DIR */ + +static const char * const backup_args[] = +{ + /* In a series of synonyms, present the most meaning full first, so + that argmatch_valid be more readable. */ + "none", "off", + "simple", "never", + "existing", "nil", + "numbered", "t", + 0 +}; + +static const enum backup_type backup_types[] = +{ + none, none, + simple, simple, + numbered_existing, numbered_existing, + numbered, numbered +}; + +/* Return the type of backup specified by VERSION. + If VERSION is NULL or the empty string, return numbered_existing. + If VERSION is invalid or ambiguous, fail with a diagnostic appropriate + for the specified CONTEXT. Unambiguous abbreviations are accepted. */ + +enum backup_type +get_version (const char *context, const char *version) +{ + if (version == 0 || *version == 0) + return numbered_existing; + else + return XARGMATCH (context, version, backup_args, backup_types); +} + + +/* Return the type of backup specified by VERSION. + If VERSION is NULL, use the value of the envvar VERSION_CONTROL. + If the specified string is invalid or ambiguous, fail with a diagnostic + appropriate for the specified CONTEXT. + Unambiguous abbreviations are accepted. */ + +enum backup_type +xget_version (const char *context, const char *version) +{ + if (version && *version) + return get_version (context, version); + else + return get_version ("$VERSION_CONTROL", getenv ("VERSION_CONTROL")); +} |
