[PATCH] cp: add -u/--update and --remove-destination

[shen long]

This is my first patch just after reviewing the code for a few
minutes,  so bear with me. It just works for me in all my tests, so I
hope it gets reviewed

On 5/21/16, wdlkmpx <wdlkmpx at gmail.com> wrote:
> This matches the behavior of GNU coreutils
> ---
>  coreutils/cp.c    | 14 +++++++++++---
>  include/libbb.h   |  2 ++
>  libbb/copy_file.c | 22 ++++++++++++++++++++++
>  3 files changed, 35 insertions(+), 3 deletions(-)
>
> diff --git a/coreutils/cp.c b/coreutils/cp.c
> index 247ed0f..cd947be 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 if SOURCE file is newer than the destination"
>
>  #include "libbb.h"
>  #include "libcoreutils/coreutils.h"
> @@ -53,8 +54,10 @@ int cp_main(int argc, char **argv)
>  		OPT_r = 1 << (sizeof(FILEUTILS_CP_OPTSTR)),
>  		OPT_P = 1 << (sizeof(FILEUTILS_CP_OPTSTR)+1),
>  		OPT_v = 1 << (sizeof(FILEUTILS_CP_OPTSTR)+2),
> +		OPT_u = 1 << (sizeof(FILEUTILS_CP_OPTSTR)+3),
>  #if ENABLE_FEATURE_CP_LONG_OPTIONS
> -		OPT_parents = 1 << (sizeof(FILEUTILS_CP_OPTSTR)+3),
> +		OPT_parents = 1 << (sizeof(FILEUTILS_CP_OPTSTR)+4),
> +		OPT_rmdest  = 1 << (sizeof(FILEUTILS_CP_OPTSTR)+5),
>  #endif
>  	};
>
> @@ -76,10 +79,12 @@ 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"
> +		"parents\0"        No_argument "\xfe"
> +		"remove-destination\0" No_argument "\xff"
>  		;
>  #endif
> -	flags = getopt32(argv, FILEUTILS_CP_OPTSTR "arPv");
> +	flags = getopt32(argv, FILEUTILS_CP_OPTSTR "arPvu");
>  	/* Options of cp from GNU coreutils 6.10:
>  	 * -a, --archive
>  	 * -f, --force
> @@ -161,6 +166,9 @@ int cp_main(int argc, char **argv)
>  				bb_error_msg_and_die("with --parents, the destination must be a
> directory");
>  			}
>  		}
> +		if (flags & OPT_rmdest) {
> +			flags |= FILEUTILS_RMDEST;
> +		}
>  #endif
>
>  		/* ...if neither is a directory...  */
> diff --git a/include/libbb.h b/include/libbb.h
> index fd40ef7..ece5f32 100644
> --- a/include/libbb.h
> +++ b/include/libbb.h
> @@ -368,6 +368,8 @@ enum {	/* DO NOT CHANGE THESE VALUES!  cp.c, mv.c,
> install.c depend on them. */
>  	FILEUTILS_IGNORE_CHMOD_ERR = 1 << 11,
>  	/* -v */
>  	FILEUTILS_VERBOSE         = (1 << 12) * ENABLE_FEATURE_VERBOSE,
> +	FILEUTILS_UPDATE          = 1 << 13, /* -u */
> +	FILEUTILS_RMDEST          = 1 << 14, /* cp --remove-destination */
>  };
>  #define FILEUTILS_CP_OPTSTR "pdRfilsLH" IF_SELINUX("c")
>  extern int remove_file(const char *path, int flags) FAST_FUNC;
> diff --git a/libbb/copy_file.c b/libbb/copy_file.c
> index a4be875..44031f2 100644
> --- a/libbb/copy_file.c
> +++ b/libbb/copy_file.c
> @@ -208,6 +208,28 @@ int FAST_FUNC copy_file(const char *source, const char
> *dest, int flags)
>  			/* retval = -1; - WRONG! copy *WAS* made */
>  		}
>  		goto preserve_mode_ugid_time;
> +	} else {
> +		/* Not a directory */
> +		if (dest_exists) {
> +			if (flags & FILEUTILS_UPDATE) {
> +				if (source_stat.st_mtime <= dest_stat.st_mtime) {
> +					return 0; /* source file must be newer */
> +				}
> +			}
> +			if (flags & FILEUTILS_RMDEST) {
> +				if (unlink(dest) < 0) {
> +					if (flags & FILEUTILS_VERBOSE) {
> +						printf("can't remove '%s'\n", dest);
> +					}
> +					return -1;
> +				} else {
> +					if (flags & FILEUTILS_VERBOSE) {
> +						printf("removed '%s'\n", dest);
> +					}
> +					dest_exists = 0;
> +				}
> +			}
> +		}
>  	}
>
>  	if (flags & (FILEUTILS_MAKE_SOFTLINK|FILEUTILS_MAKE_HARDLINK)) {
> --
> 2.8.3
>
>