cp: add -u/--update and --remove-destination

Based on the patch by wdlkmpx@gmail.com

function                                             old     new   delta
copy_file                                           1546    1644     +98
add_partition                                       1270    1362     +92
ask_and_unlink                                        95     133     +38
do_iproute                                           132     157     +25
decode_one_format                                    710     715      +5
cp_main                                              369     374      +5
ubirename_main                                       198     202      +4
read_package_field                                   232     230      -2
bb_make_directory                                    421     412      -9
packed_usage                                       30505   30476     -29
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 7/3 up/down: 267/-40)           Total: 227 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

3 files changed, 56 insertions, 19 deletions

diff --git a/coreutils/cp.c b/coreutils/cp.c
index 247ed0f..2630c0d 100644
--- a/coreutils/cp.c
+++ b/coreutils/cp.c
@@ -31,6 +31,7 @@
 //usage:     "\n	-f	Overwrite"
 //usage:     "\n	-i	Prompt before overwrite"
 //usage:     "\n	-l,-s	Create (sym)links"
+//usage:     "\n	-u	Copy only newer files"
 
 #include "libbb.h"
 #include "libcoreutils/coreutils.h"
@@ -49,12 +50,10 @@ int cp_main(int argc, char **argv)
 	int flags;
 	int status;
 	enum {
-		OPT_a = 1 << (sizeof(FILEUTILS_CP_OPTSTR)-1),
-		OPT_r = 1 << (sizeof(FILEUTILS_CP_OPTSTR)),
-		OPT_P = 1 << (sizeof(FILEUTILS_CP_OPTSTR)+1),
-		OPT_v = 1 << (sizeof(FILEUTILS_CP_OPTSTR)+2),
+		FILEUTILS_CP_OPTNUM = sizeof(FILEUTILS_CP_OPTSTR)-1,
 #if ENABLE_FEATURE_CP_LONG_OPTIONS
-		OPT_parents = 1 << (sizeof(FILEUTILS_CP_OPTSTR)+3),
+		/*OPT_rmdest  = FILEUTILS_RMDEST = 1 << FILEUTILS_CP_OPTNUM */
+		OPT_parents = 1 << (FILEUTILS_CP_OPTNUM+1),
 #endif
 	};
 
@@ -76,10 +75,12 @@ int cp_main(int argc, char **argv)
 		"recursive\0"      No_argument "R"
 		"symbolic-link\0"  No_argument "s"
 		"verbose\0"        No_argument "v"
-		"parents\0"        No_argument "\xff"
+		"update\0"         No_argument "u"
+		"remove-destination\0" No_argument "\xff"
+		"parents\0"        No_argument "\xfe"
 		;
 #endif
-	flags = getopt32(argv, FILEUTILS_CP_OPTSTR "arPv");
+	flags = getopt32(argv, FILEUTILS_CP_OPTSTR);
 	/* Options of cp from GNU coreutils 6.10:
 	 * -a, --archive
 	 * -f, --force
@@ -94,6 +95,11 @@ int cp_main(int argc, char **argv)
 	 * -d	same as --no-dereference --preserve=links
 	 * -p	same as --preserve=mode,ownership,timestamps
 	 * -c	same as --preserve=context
+	 * -u, --update
+	 *	copy only when the SOURCE file is newer than the destination
+	 *	file or when the destination file is missing
+	 * --remove-destination
+	 *	remove each existing destination file before attempting to open
 	 * --parents
 	 *	use full source file name under DIRECTORY
 	 * NOT SUPPORTED IN BBOX:
@@ -106,8 +112,6 @@ int cp_main(int argc, char **argv)
 	 *	preserve attributes (default: mode,ownership,timestamps),
 	 *	if possible additional attributes: security context,links,all
 	 * --no-preserve=ATTR_LIST
-	 * --remove-destination
-	 *	remove  each existing destination file before attempting to open
 	 * --sparse=WHEN
 	 *	control creation of sparse files
 	 * --strip-trailing-slashes
@@ -118,9 +122,6 @@ int cp_main(int argc, char **argv)
 	 *	copy all SOURCE arguments into DIRECTORY
 	 * -T, --no-target-directory
 	 *	treat DEST as a normal file
-	 * -u, --update
-	 *	copy only when the SOURCE file is newer than the destination
-	 *	file or when the destination file is missing
 	 * -x, --one-file-system
 	 *	stay on this file system
 	 * -Z, --context=CONTEXT
@@ -156,11 +157,16 @@ int cp_main(int argc, char **argv)
 			return EXIT_FAILURE;
 
 #if ENABLE_FEATURE_CP_LONG_OPTIONS
+		//bb_error_msg("flags:%x FILEUTILS_RMDEST:%x OPT_parents:%x",
+		//	flags, FILEUTILS_RMDEST, OPT_parents);
 		if (flags & OPT_parents) {
 			if (!(d_flags & 2)) {
 				bb_error_msg_and_die("with --parents, the destination must be a directory");
 			}
 		}
+		if (flags & FILEUTILS_RMDEST) {
+			flags |= FILEUTILS_FORCE;
+		}
 #endif
 
 		/* ...if neither is a directory...  */
diff --git a/include/libbb.h b/include/libbb.h
index fd40ef7..a21f420 100644
--- a/include/libbb.h
+++ b/include/libbb.h
@@ -351,7 +351,7 @@ extern char *strrstr(const char *haystack, const char *needle) FAST_FUNC;
 //TODO: supply a pointer to char[11] buffer (avoid statics)?
 extern const char *bb_mode_string(mode_t mode) FAST_FUNC;
 extern int is_directory(const char *name, int followLinks) FAST_FUNC;
-enum {	/* DO NOT CHANGE THESE VALUES!  cp.c, mv.c, install.c depend on them. */
+enum {	/* cp.c, mv.c, install.c depend on these values. CAREFUL when changing them! */
 	FILEUTILS_PRESERVE_STATUS = 1 << 0, /* -p */
 	FILEUTILS_DEREFERENCE     = 1 << 1, /* !-d */
 	FILEUTILS_RECUR           = 1 << 2, /* -R */
@@ -361,15 +361,25 @@ enum {	/* DO NOT CHANGE THESE VALUES!  cp.c, mv.c, install.c depend on them. */
 	FILEUTILS_MAKE_SOFTLINK   = 1 << 6, /* -s */
 	FILEUTILS_DEREF_SOFTLINK  = 1 << 7, /* -L */
 	FILEUTILS_DEREFERENCE_L0  = 1 << 8, /* -H */
+	/* -a = -pdR (mapped in cp.c) */
+	/* -r = -dR  (mapped in cp.c) */
+	/* -P = -d   (mapped in cp.c) */
+	FILEUTILS_VERBOSE         = (1 << 12) * ENABLE_FEATURE_VERBOSE,	/* -v */
+	FILEUTILS_UPDATE          = 1 << 13, /* -u */
 #if ENABLE_SELINUX
-	FILEUTILS_PRESERVE_SECURITY_CONTEXT = 1 << 9, /* -c */
-	FILEUTILS_SET_SECURITY_CONTEXT = 1 << 10,
+	FILEUTILS_PRESERVE_SECURITY_CONTEXT = 1 << 14, /* -c */
 #endif
-	FILEUTILS_IGNORE_CHMOD_ERR = 1 << 11,
-	/* -v */
-	FILEUTILS_VERBOSE         = (1 << 12) * ENABLE_FEATURE_VERBOSE,
+	FILEUTILS_RMDEST          = 1 << (15 - !ENABLE_SELINUX), /* --remove-destination */
+	/*
+	 * Hole. cp may have some bits set here,
+	 * they should not affect remove_file()/copy_file()
+	 */
+#if ENABLE_SELINUX
+	FILEUTILS_SET_SECURITY_CONTEXT = 1 << 30,
+#endif
+	FILEUTILS_IGNORE_CHMOD_ERR = 1 << 31,
 };
-#define FILEUTILS_CP_OPTSTR "pdRfilsLH" IF_SELINUX("c")
+#define FILEUTILS_CP_OPTSTR "pdRfilsLHarPvu" IF_SELINUX("c")
 extern int remove_file(const char *path, int flags) FAST_FUNC;
 /* NB: without FILEUTILS_RECUR in flags, it will basically "cat"
  * the source, not copy (unless "source" is a directory).
diff --git a/libbb/copy_file.c b/libbb/copy_file.c
index a4be875..23bcf2e 100644
--- a/libbb/copy_file.c
+++ b/libbb/copy_file.c
@@ -64,6 +64,11 @@ static int ask_and_unlink(const char *dest, int flags)
 		bb_perror_msg("can't create '%s'", dest);
 		return -1; /* error */
 	}
+#if ENABLE_FEATURE_CP_LONG_OPTIONS
+	if (flags & FILEUTILS_RMDEST)
+		if (flags & FILEUTILS_VERBOSE)
+			printf("removed '%s'\n", dest);
+#endif
 	return 1; /* ok (to try again) */
 }
 
@@ -210,6 +215,22 @@ int FAST_FUNC copy_file(const char *source, const char *dest, int flags)
 		goto preserve_mode_ugid_time;
 	}
 
+	if (dest_exists) {
+		if (flags & FILEUTILS_UPDATE) {
+			if (source_stat.st_mtime <= dest_stat.st_mtime) {
+				return 0; /* source file must be newer */
+			}
+		}
+#if ENABLE_FEATURE_CP_LONG_OPTIONS
+		if (flags & FILEUTILS_RMDEST) {
+			ovr = ask_and_unlink(dest, flags);
+			if (ovr <= 0)
+				return ovr;
+			dest_exists = 0;
+		}
+#endif
+	}
+
 	if (flags & (FILEUTILS_MAKE_SOFTLINK|FILEUTILS_MAKE_HARDLINK)) {
 		int (*lf)(const char *oldpath, const char *newpath);
  make_links: