From 1af81dfb4d24d104777b8917544d81097db0deab Mon Sep 17 00:00:00 2001 From: Pádraig Brady Date: Mon, 21 Sep 2009 08:43:03 +0100 Subject: cp: add an option to only copy the file attributes * src/copy.c (copy_attr): A new function which merges copy_attr_by_fd and copy_attr_by_name. Also display all errors when --attributes-only * src/copy.c (copy_reg): Skip copying the file contents if specified. Refactor the SELinux error handling code a little and display all SELinux errors when only copying attributes. * src/copy.h (struct cp_options): Add a data_copy_required boolean * src/cp.c (main): Default to copying data but don't if specified * src/install.c: Default to copying data * src/mv.c: Likewise tests/cp/reflink-perm: Add a test to check that --attributes-only does not copy data * tests/cp/acl: Likewise. Also refactor to remove redundant acl manipulation * doc/coreutils.texi (cp invocation): Describe the new option * NEWS: Mention the new feature --- NEWS | 3 ++ doc/coreutils.texi | 6 ++++ src/copy.c | 84 +++++++++++++++++++++++---------------------------- src/copy.h | 4 +++ src/cp.c | 10 +++++- src/install.c | 1 + src/mv.c | 1 + tests/cp/acl | 22 ++++++++------ tests/cp/reflink-perm | 4 +++ 9 files changed, 78 insertions(+), 57 deletions(-) diff --git a/NEWS b/NEWS index 2bacb7f0e..3a249254f 100644 --- a/NEWS +++ b/NEWS @@ -4,6 +4,9 @@ GNU coreutils NEWS -*- outline -*- ** New features + cp now accepts the --attributes-only option to not copy file data, + which is useful for efficiently modifying files. + du recognizes -d N as equivalent to --max-depth=N, for compatibility with FreeBSD. diff --git a/doc/coreutils.texi b/doc/coreutils.texi index 5c2bd1a84..21cf36d1d 100644 --- a/doc/coreutils.texi +++ b/doc/coreutils.texi @@ -7357,6 +7357,12 @@ Try to preserve SELinux security context and extended attributes (xattr), but ignore any failure to do that and print no corresponding diagnostic. Equivalent to @option{-dR --preserve=all} with the reduced diagnostics. +@itemx --attributes-only +@opindex --attributes-only +Preserve the specified attributes of the original files in the copy, +but do not copy any data. See the @option{--preserve} option for +controlling which attributes to copy. + @item -b @itemx @w{@kbd{--backup}[=@var{method}]} @opindex -b diff --git a/src/copy.c b/src/copy.c index 171499c47..6d11ed868 100644 --- a/src/copy.c +++ b/src/copy.c @@ -177,11 +177,11 @@ static void copy_attr_error (struct error_context *ctx ATTRIBUTE_UNUSED, char const *fmt, ...) { - int err = errno; - va_list ap; - if (!errno_unsupported (errno)) { + int err = errno; + va_list ap; + /* use verror module to print error message */ va_start (ap, fmt); verror (0, err, fmt, ap); @@ -214,51 +214,39 @@ copy_attr_free (struct error_context *ctx ATTRIBUTE_UNUSED, { } -static bool -copy_attr_by_fd (char const *src_path, int src_fd, - char const *dst_path, int dst_fd, const struct cp_options *x) -{ - struct error_context ctx = - { - .error = x->require_preserve_xattr ? copy_attr_allerror : copy_attr_error, - .quote = copy_attr_quote, - .quote_free = copy_attr_free - }; - return 0 == attr_copy_fd (src_path, src_fd, dst_path, dst_fd, 0, - (x->reduce_diagnostics - && !x->require_preserve_xattr)? NULL : &ctx); -} +/* If positive SRC_FD and DST_FD descriptors are passed, + then copy by fd, otherwise copy by name. */ static bool -copy_attr_by_name (char const *src_path, char const *dst_path, - const struct cp_options *x) +copy_attr (char const *src_path, int src_fd, + char const *dst_path, int dst_fd, struct cp_options const *x) { + int ret; + bool all_errors = (!x->data_copy_required || x->require_preserve_xattr); + bool some_errors = (!all_errors && !x->reduce_diagnostics); struct error_context ctx = { - .error = x->require_preserve_xattr ? copy_attr_allerror : copy_attr_error, + .error = all_errors ? copy_attr_allerror : copy_attr_error, .quote = copy_attr_quote, .quote_free = copy_attr_free }; - return 0 == attr_copy_file (src_path, dst_path, 0, - (x-> reduce_diagnostics - && !x->require_preserve_xattr) ? NULL : &ctx); -} -#else /* USE_XATTR */ + if (0 <= src_fd && 0 <= dst_fd) + ret = attr_copy_fd (src_path, src_fd, dst_path, dst_fd, 0, + (all_errors || some_errors ? &ctx : NULL)); + else + ret = attr_copy_file (src_path, dst_path, 0, + (all_errors || some_errors ? &ctx : NULL)); -static bool -copy_attr_by_fd (char const *src_path ATTRIBUTE_UNUSED, - int src_fd ATTRIBUTE_UNUSED, - char const *dst_path ATTRIBUTE_UNUSED, - int dst_fd ATTRIBUTE_UNUSED, - const struct cp_options *x ATTRIBUTE_UNUSED) -{ - return true; + return ret == 0; } +#else /* USE_XATTR */ static bool -copy_attr_by_name (char const *src_path ATTRIBUTE_UNUSED, - char const *dst_path ATTRIBUTE_UNUSED, - const struct cp_options *x ATTRIBUTE_UNUSED) +copy_attr (char const *src_path ATTRIBUTE_UNUSED, + int src_fd ATTRIBUTE_UNUSED, + char const *dst_path ATTRIBUTE_UNUSED, + int dst_fd ATTRIBUTE_UNUSED, + struct cp_options const *x ATTRIBUTE_UNUSED) { return true; } @@ -483,7 +471,7 @@ copy_reg (char const *src_name, char const *dst_name, struct stat sb; struct stat src_open_sb; bool return_val = true; - bool data_copy_required = true; + bool data_copy_required = x->data_copy_required; source_desc = open (src_name, (O_RDONLY | O_BINARY @@ -526,11 +514,14 @@ copy_reg (char const *src_name, char const *dst_name, that is used when the destination file doesn't already exist. */ if (x->preserve_security_context && 0 <= dest_desc) { + bool all_errors = (!x->data_copy_required + || x->require_preserve_context); + bool some_errors = !all_errors && !x->reduce_diagnostics; security_context_t con = NULL; + if (getfscreatecon (&con) < 0) { - if (x->require_preserve_context || - (!x->reduce_diagnostics && !errno_unsupported (errno))) + if (all_errors || (some_errors && !errno_unsupported (errno))) error (0, errno, _("failed to get file system create context")); if (x->require_preserve_context) { @@ -543,8 +534,7 @@ copy_reg (char const *src_name, char const *dst_name, { if (fsetfilecon (dest_desc, con) < 0) { - if (x->require_preserve_context || - (!x->reduce_diagnostics && !errno_unsupported (errno))) + if (all_errors || (some_errors && !errno_unsupported (errno))) error (0, errno, _("failed to set the security context of %s to %s"), quote_n (0, dst_name), quote_n (1, con)); @@ -850,7 +840,7 @@ copy_reg (char const *src_name, char const *dst_name, if (!(sb.st_mode & S_IWUSR) && geteuid () != 0) access_changed = fchmod_or_lchmod (dest_desc, dst_name, 0600) == 0; - if (!copy_attr_by_fd (src_name, source_desc, dst_name, dest_desc, x) + if (!copy_attr (src_name, source_desc, dst_name, dest_desc, x) && x->require_preserve_xattr) return_val = false; @@ -1821,14 +1811,15 @@ copy_internal (char const *src_name, char const *dst_name, if (x->preserve_security_context) { + bool all_errors = !x->data_copy_required || x->require_preserve_context; + bool some_errors = !all_errors && !x->reduce_diagnostics; security_context_t con; if (0 <= lgetfilecon (src_name, &con)) { if (setfscreatecon (con) < 0) { - if (x->require_preserve_context || - (!x->reduce_diagnostics && !errno_unsupported (errno))) + if (all_errors || (some_errors && !errno_unsupported (errno))) error (0, errno, _("failed to set default file creation context to %s"), quote (con)); @@ -1842,8 +1833,7 @@ copy_internal (char const *src_name, char const *dst_name, } else { - if (x->require_preserve_context || - (!x->reduce_diagnostics && !errno_unsupported (errno))) + if (all_errors || (some_errors && !errno_unsupported (errno))) { error (0, errno, _("failed to get security context of %s"), @@ -2168,7 +2158,7 @@ copy_internal (char const *src_name, char const *dst_name, set_author (dst_name, -1, &src_sb); - if (x->preserve_xattr && ! copy_attr_by_name (src_name, dst_name, x) + if (x->preserve_xattr && ! copy_attr (src_name, -1, dst_name, -1, x) && x->require_preserve_xattr) return false; diff --git a/src/copy.h b/src/copy.h index 59e29f53b..7c7e3f312 100644 --- a/src/copy.h +++ b/src/copy.h @@ -170,6 +170,10 @@ struct cp_options will be hard links to the same file (a copy of F). */ bool preserve_links; + /* Optionally don't copy the data, either with CoW reflink files or + explicitly with the --attributes-only option. */ + bool data_copy_required; + /* If true and any of the above (for preserve) file attributes cannot be applied to a destination file, treat it as a failure and return nonzero immediately. E.g. for cp -p this must be true, for mv it diff --git a/src/cp.c b/src/cp.c index 035526922..5b14f3a7b 100644 --- a/src/cp.c +++ b/src/cp.c @@ -72,7 +72,8 @@ struct dir_attr non-character as a pseudo short option, starting with CHAR_MAX + 1. */ enum { - COPY_CONTENTS_OPTION = CHAR_MAX + 1, + ATTRIBUTES_ONLY_OPTION = CHAR_MAX + 1, + COPY_CONTENTS_OPTION, NO_PRESERVE_ATTRIBUTES_OPTION, PARENTS_OPTION, PRESERVE_ATTRIBUTES_OPTION, @@ -115,6 +116,7 @@ ARGMATCH_VERIFY (reflink_type_string, reflink_type); static struct option const long_opts[] = { {"archive", no_argument, NULL, 'a'}, + {"attributes-only", no_argument, NULL, ATTRIBUTES_ONLY_OPTION}, {"backup", optional_argument, NULL, 'b'}, {"copy-contents", no_argument, NULL, COPY_CONTENTS_OPTION}, {"dereference", no_argument, NULL, 'L'}, @@ -167,6 +169,7 @@ Mandatory arguments to long options are mandatory for short options too.\n\ "), stdout); fputs (_("\ -a, --archive same as -dR --preserve=all\n\ + --attributes-only don't copy the file data, just the attributes\n\ --backup[=CONTROL] make a backup of each existing destination file\n\ -b like --backup but does not accept an argument\n\ --copy-contents copy contents of special files when recursive\n\ @@ -781,6 +784,7 @@ cp_option_init (struct cp_options *x) x->reduce_diagnostics = false; x->require_preserve_xattr = false; + x->data_copy_required = true; x->require_preserve = false; x->recursive = false; x->sparse_mode = SPARSE_AUTO; @@ -962,6 +966,10 @@ main (int argc, char **argv) version_control_string = optarg; break; + case ATTRIBUTES_ONLY_OPTION: + x.data_copy_required = false; + break; + case COPY_CONTENTS_OPTION: copy_contents = true; break; diff --git a/src/install.c b/src/install.c index 038e86976..97029140c 100644 --- a/src/install.c +++ b/src/install.c @@ -280,6 +280,7 @@ cp_option_init (struct cp_options *x) x->preserve_mode = false; x->preserve_timestamps = false; x->reduce_diagnostics=false; + x->data_copy_required = true; x->require_preserve = false; x->require_preserve_context = false; x->require_preserve_xattr = false; diff --git a/src/mv.c b/src/mv.c index 8a41d16f9..91aadfa0e 100644 --- a/src/mv.c +++ b/src/mv.c @@ -119,6 +119,7 @@ cp_option_init (struct cp_options *x) x->preserve_timestamps = true; x->preserve_security_context = selinux_enabled; x->reduce_diagnostics = false; + x->data_copy_required = true; x->require_preserve = false; /* FIXME: maybe make this an option */ x->require_preserve_context = false; x->preserve_xattr = true; diff --git a/tests/cp/acl b/tests/cp/acl index 010348a9d..c19eb4e93 100755 --- a/tests/cp/acl +++ b/tests/cp/acl @@ -36,28 +36,32 @@ grep '^#define USE_ACL 1' $CONFIG_HEADER > /dev/null || mkdir -p a b || framework_failure touch a/file || framework_failure -skip=no # Ensure that setfacl and getfacl work on this file system. +skip=no +acl1=`cd a && getfacl file` || skip=yes setfacl -m user:bin:rw a/file 2> /dev/null || skip=yes -acl1=`cd a && getfacl file | grep -v ':bin:' | grep -v 'mask::'` \ - || skip=yes - test $skip = yes && skip_test_ "'.' is not on a suitable file system for this test" # copy a file without preserving permissions cp a/file b/ || fail=1 - acl2=`cd b && getfacl file` || framework_failure test "$acl1" = "$acl2" || fail=1 -rm a/file || framework_failure -# copy a file, preserving permissions -touch a/file || framework_failure -setfacl -m user:bin:rw a/file || framework_failure +# Update with acl set above acl1=`cd a && getfacl file` || framework_failure + +# copy a file, preserving permissions cp -p a/file b/ || fail=1 acl2=`cd b && getfacl file` || framework_failure test "$acl1" = "$acl2" || fail=1 +# copy a file, preserving permissions, with --attributes-only +echo > a/file || framework_failure # add some data +test -s a/file || framework_failure +cp -p --attributes-only a/file b/ || fail=1 +test -s b/file && fail=1 +acl2=`cd b && getfacl file` || framework_failure +test "$acl1" = "$acl2" || fail=1 + Exit $fail diff --git a/tests/cp/reflink-perm b/tests/cp/reflink-perm index 92cb7ae8f..77f119f4a 100755 --- a/tests/cp/reflink-perm +++ b/tests/cp/reflink-perm @@ -39,4 +39,8 @@ test "$mode" = "-rwxrwxrwx" || fail=1 test copy -nt file && fail=1 +echo > file2 # file with data +cp --reflink=auto --preserve --attributes-only file2 empty_copy || fail=1 +test -s empty_copy && fail=1 + Exit $fail -- cgit v1.2.3-70-g09d2