1 files changed, 237 insertions, 0 deletions
diff --git a/usr.bin/patch/backupfile.c b/usr.bin/patch/backupfile.c
new file mode 100644
index 0000000..243d00e
--- /dev/null
+++ b/usr.bin/patch/backupfile.c
@@ -0,0 +1,237 @@
+/*	$OpenBSD: backupfile.c,v 1.21 2013/11/26 13:19:07 deraadt Exp $	*/
+
+/*
+ * backupfile.c -- make Emacs style backup file names Copyright (C) 1990 Free
+ * Software Foundation, Inc.
+ * 
+ * This program is free software; you can redistribute it and/or modify it
+ * without restriction.
+ * 
+ * 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.
+ */
+
+/*
+ * David MacKenzie <djm@ai.mit.edu>. Some algorithms adapted from GNU Emacs.
+ */
+
+#include <ctype.h>
+#include <dirent.h>
+#include <libgen.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "backupfile.h"
+
+
+#define ISDIGIT(c) (isascii (c) && isdigit (c))
+
+/* Which type of backup file names are generated. */
+enum backup_type backup_type = none;
+
+/*
+ * The extension added to file names to produce a simple (as opposed to
+ * numbered) backup file name.
+ */
+char		*simple_backup_suffix = "~";
+
+static char	*concat(const char *, const char *);
+static char	*make_version_name(const char *, int);
+static int	max_backup_version(const char *, const char *);
+static int	version_number(const char *, const char *, size_t);
+static int	argmatch(const char *, const char **);
+static void	invalid_arg(const char *, const char *, int);
+
+/*
+ * 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)
+{
+	char	*path, *base_versions;
+	int	highest_backup;
+
+	if (backup_type == simple)
+		return concat(file, simple_backup_suffix);
+	path = strdup(file);
+	if (path == NULL)
+		return NULL;
+	base_versions = concat(basename(path), ".~");
+	if (base_versions == NULL) {
+		free(path);
+		return NULL;
+	}
+	highest_backup = max_backup_version(base_versions, dirname(path));
+	free(base_versions);
+	free(path);
+	if (backup_type == numbered_existing && highest_backup == 0)
+		return concat(file, simple_backup_suffix);
+	return make_version_name(file, highest_backup + 1);
+}
+
+/*
+ * 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. FILE should already have ".~" appended
+ * to it.
+ */
+static int
+max_backup_version(const char *file, const char *dir)
+{
+	DIR	*dirp;
+	struct dirent	*dp;
+	int	highest_version, this_version;
+	size_t	file_name_length;
+
+	dirp = opendir(dir);
+	if (dirp == NULL)
+		return 0;
+
+	highest_version = 0;
+	file_name_length = strlen(file);
+
+	while ((dp = readdir(dirp)) != NULL) {
+		if (strlen(dp->d_name) <= file_name_length)
+			continue;
+
+		this_version = version_number(file, dp->d_name, file_name_length);
+		if (this_version > highest_version)
+			highest_version = this_version;
+	}
+	closedir(dirp);
+	return highest_version;
+}
+
+/*
+ * Return a string, allocated with malloc, containing "FILE.~VERSION~".
+ * Return 0 if out of memory.
+ */
+static char *
+make_version_name(const char *file, int version)
+{
+	char	*backup_name;
+
+	if (asprintf(&backup_name, "%s.~%d~", file, version) == -1)
+		return NULL;
+	return backup_name;
+}
+
+/*
+ * If BACKUP is a numbered backup of BASE, return its version number;
+ * otherwise return 0.  BASE_LENGTH is the length of BASE. BASE should
+ * already have ".~" appended to it.
+ */
+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) &&
+	    ISDIGIT((unsigned char)backup[base_length])) {
+		for (p = &backup[base_length]; ISDIGIT((unsigned char)*p); ++p)
+			version = version * 10 + *p - '0';
+		if (p[0] != '~' || p[1])
+			version = 0;
+	}
+	return version;
+}
+
+/*
+ * Return the newly-allocated concatenation of STR1 and STR2. If out of
+ * memory, return 0.
+ */
+static char  *
+concat(const char *str1, const char *str2)
+{
+	char	*newstr;
+
+	if (asprintf(&newstr, "%s%s", str1, str2) == -1)
+		return NULL;
+	return newstr;
+}
+
+/*
+ * If ARG is an unambiguous match for an element of the null-terminated array
+ * OPTLIST, return the index in OPTLIST of the matched element, else -1 if it
+ * does not match any element or -2 if it is ambiguous (is a prefix of more
+ * than one element).
+ */
+static int
+argmatch(const char *arg, const char **optlist)
+{
+	int	i;	/* Temporary index in OPTLIST. */
+	size_t	arglen;	/* Length of ARG. */
+	int	matchind = -1;	/* Index of first nonexact match. */
+	int	ambiguous = 0;	/* If nonzero, multiple nonexact match(es). */
+
+	arglen = strlen(arg);
+
+	/* Test all elements for either exact match or abbreviated matches.  */
+	for (i = 0; optlist[i]; i++) {
+		if (!strncmp(optlist[i], arg, arglen)) {
+			if (strlen(optlist[i]) == arglen)
+				/* Exact match found.  */
+				return i;
+			else if (matchind == -1)
+				/* First nonexact match found.  */
+				matchind = i;
+			else
+				/* Second nonexact match found.  */
+				ambiguous = 1;
+		}
+	}
+	if (ambiguous)
+		return -2;
+	else
+		return matchind;
+}
+
+/*
+ * Error reporting for argmatch. KIND is a description of the type of entity
+ * that was being matched. VALUE is the invalid value that was given. PROBLEM
+ * is the return value from argmatch.
+ */
+static void
+invalid_arg(const char *kind, const char *value, int problem)
+{
+	fprintf(stderr, "patch: ");
+	if (problem == -1)
+		fprintf(stderr, "invalid");
+	else			/* Assume -2. */
+		fprintf(stderr, "ambiguous");
+	fprintf(stderr, " %s `%s'\n", kind, value);
+}
+
+static const char *backup_args[] = {
+	"never", "simple", "nil", "existing", "t", "numbered", 0
+};
+
+static enum backup_type backup_types[] = {
+	simple, simple, numbered_existing,
+	numbered_existing, numbered, numbered
+};
+
+/*
+ * Return the type of backup indicated by VERSION. Unique abbreviations are
+ * accepted.
+ */
+enum backup_type
+get_version(const char *version)
+{
+	int	i;
+
+	if (version == NULL || *version == '\0')
+		return numbered_existing;
+	i = argmatch(version, backup_args);
+	if (i >= 0)
+		return backup_types[i];
+	invalid_arg("version control type", version, i);
+	exit(2);
+}