hardlink: add --respect-dir

Fixes: https://github.com/util-linux/util-linux/issues/1942
Signed-off-by: Karel Zak <kzak@redhat.com>

diff --git a/misc-utils/hardlink.1.adoc b/misc-utils/hardlink.1.adoc
index 9327a889cd6e67db8ac012c5766125060a59e6a4..b0feb08c866fedc2e8deb3436906a15025f0c34b 100644 (file)
--- a/misc-utils/hardlink.1.adoc
+++ b/misc-utils/hardlink.1.adoc
@@ -61,6 +61,9 @@ calculation is done in kernel.
 *-f*, *--respect-name*::
 Only try to link files with the same (base)name. It's strongly recommended to use long options rather than *-f* which is interpreted in a different way by other *hardlink* implementations.
 
+*-d*, *--respect-dir*::
+Only try to link files with the same directory name. The top-level directory (as specified on the hardlink command line) is ignored. For example, *hardlink --respect-dir /foo /bar* will link /foo/some/file with /bar/some/file, but not /bar/other/file. If combined with *--respect-name*, then entire paths (except the top-level directory) are compared.
+
 *-p*, *--ignore-mode*::
 Link and compare files even if their mode is different. Results may be slightly unpredictable.
 

diff --git a/misc-utils/hardlink.c b/misc-utils/hardlink.c
index 5de09ca1590585c7ed2bc9c6466279b80e19eaf0..d73974be90f78f75f063f69b00db3dd21f1d0f6e 100644 (file)
--- a/misc-utils/hardlink.c
+++ b/misc-utils/hardlink.c
@@ -66,6 +66,7 @@
 #endif
 
 static int quiet;              /* don't print anything */
+static int rootbasesz;         /* size of the directory for nftw() */
 
 #ifdef USE_REFLINK
 enum {
@@ -96,6 +97,7 @@ struct file {
        struct link {
                struct link *next;
                int basename;
+               int dirname;
 #if __STDC_VERSION__ >= 199901L
                char path[];
 #elif __GNUC__
@@ -174,6 +176,7 @@ static struct options {
        unsigned int respect_mode:1;
        unsigned int respect_owner:1;
        unsigned int respect_name:1;
+       unsigned int respect_dir:1;
        unsigned int respect_time:1;
        unsigned int respect_xattrs:1;
        unsigned int maximise:1;
@@ -310,6 +313,41 @@ static int compare_nodes(const void *_a, const void *_b)
        return diff;
 }
 
+/* Compare only filenames */
+static inline int filename_strcmp(const struct file *a, const struct file *b)
+{
+       return strcmp(  a->links->path + a->links->basename,
+                       b->links->path + b->links->basename);
+}
+
+/**
+ * Compare only directory names (ignores root directory and basename (filename))
+ *
+ * The complete path conrains three fragments:
+ *
+ * <rootdir> is specified on hardlink command line
+ * <dirname> is all betweehn rootdir and filename
+ * <filename> is last component (aka basename)
+ */
+static inline int dirname_strcmp(const struct file *a, const struct file *b)
+{
+       int diff = 0;
+       int asz = a->links->basename - a->links->dirname,
+           bsz = b->links->basename - b->links->dirname;
+
+       diff = CMP(asz, bsz);
+
+       if (diff == 0) {
+               const char *a_start, *b_start;
+
+               a_start = a->links->path + a->links->dirname;
+               b_start = b->links->path + b->links->dirname;
+
+               diff = strncmp(a_start, b_start, asz);
+       }
+       return diff;
+}
+
 /**
  * compare_nodes_ino - Node comparison function
  * @_a: The first node (a #struct file)
@@ -332,8 +370,9 @@ static int compare_nodes_ino(const void *_a, const void *_b)
         * contain only links with the same basename to keep the rest simple.
         */
        if (diff == 0 && opts.respect_name)
-               diff = strcmp(a->links->path + a->links->basename,
-                             b->links->path + b->links->basename);
+               diff = filename_strcmp(a, b);
+       if (diff == 0 && opts.respect_dir)
+               diff = dirname_strcmp(a, b);
 
        return diff;
 }
@@ -609,9 +648,8 @@ static int file_may_link_to(const struct file *a, const struct file *b)
                (!opts.respect_owner || a->st.st_uid == b->st.st_uid) &&
                (!opts.respect_owner || a->st.st_gid == b->st.st_gid) &&
                (!opts.respect_time || a->st.st_mtime == b->st.st_mtime) &&
-               (!opts.respect_name
-                || strcmp(a->links->path + a->links->basename,
-                          b->links->path + b->links->basename) == 0) &&
+               (!opts.respect_name || filename_strcmp(a, b) == 0) &&
+               (!opts.respect_dir || dirname_strcmp(a, b) == 0) &&
                (!opts.respect_xattrs || file_xattrs_equal(a, b)));
 }
 
@@ -835,6 +873,7 @@ static int inserter(const char *fpath, const struct stat *sb,
 
        fil->st = *sb;
        fil->links->basename = ftwbuf->base;
+       fil->links->dirname = rootbasesz;
        fil->links->next = NULL;
 
        memcpy(fil->links->path, fpath, pathlen);
@@ -1128,6 +1167,7 @@ static void __attribute__((__noreturn__)) usage(void)
        fputs(_(" -y, --method <name>        file content comparison method\n"), out);
 
        fputs(_(" -f, --respect-name         filenames have to be identical\n"), out);
+       fputs(_(" -d, --respect-dir          directory names have to be identical\n"), out);
        fputs(_(" -p, --ignore-mode          ignore changes of file mode\n"), out);
        fputs(_(" -o, --ignore-owner         ignore owner changes\n"), out);
        fputs(_(" -t, --ignore-time          ignore timestamps (when testing for equality)\n"), out);
@@ -1170,13 +1210,14 @@ static int parse_options(int argc, char *argv[])
                OPT_REFLINK = CHAR_MAX + 1,
                OPT_SKIP_RELINKS
        };
-       static const char optstr[] = "VhvnfpotXcmMOx:y:i:r:S:s:b:q";
+       static const char optstr[] = "VhvndfpotXcmMOx:y:i:r:S:s:b:q";
        static const struct option long_options[] = {
                {"version", no_argument, NULL, 'V'},
                {"help", no_argument, NULL, 'h'},
                {"verbose", no_argument, NULL, 'v'},
                {"dry-run", no_argument, NULL, 'n'},
                {"respect-name", no_argument, NULL, 'f'},
+               {"respect-dir", no_argument, NULL, 'd'},
                {"ignore-mode", no_argument, NULL, 'p'},
                {"ignore-owner", no_argument, NULL, 'o'},
                {"ignore-time", no_argument, NULL, 't'},
@@ -1204,7 +1245,7 @@ static int parse_options(int argc, char *argv[])
                {0}
        };
        int excl_st[ARRAY_SIZE(excl)] = UL_EXCL_STATUS_INIT;
-       int c;
+       int c, content_only = 0;
 
        while ((c = getopt_long(argc, argv, optstr, long_options, NULL)) != -1) {
 
@@ -1235,6 +1276,9 @@ static int parse_options(int argc, char *argv[])
                case 'f':
                        opts.respect_name = TRUE;
                        break;
+               case 'd':
+                       opts.respect_dir = TRUE;
+                       break;
                case 'v':
                        opts.verbosity++;
                        break;
@@ -1242,11 +1286,7 @@ static int parse_options(int argc, char *argv[])
                        quiet = TRUE;
                        break;
                case 'c':
-                       opts.respect_mode = FALSE;
-                       opts.respect_name = FALSE;
-                       opts.respect_owner = FALSE;
-                       opts.respect_time = FALSE;
-                       opts.respect_xattrs = FALSE;
+                       content_only = 1;
                        break;
                case 'n':
                        opts.dry_run = 1;
@@ -1312,6 +1352,14 @@ static int parse_options(int argc, char *argv[])
                }
        }
 
+       if (content_only) {
+               opts.respect_mode = FALSE;
+               opts.respect_name = FALSE;
+               opts.respect_dir = FALSE;
+               opts.respect_owner = FALSE;
+               opts.respect_time = FALSE;
+               opts.respect_xattrs = FALSE;
+       }
        return 0;
 }
 
@@ -1391,9 +1439,12 @@ int main(int argc, char *argv[])
                        warn(_("cannot get realpath: %s"), argv[optind]);
                        continue;
                }
+               if (opts.respect_dir)
+                       rootbasesz = strlen(path);
                if (nftw(path, inserter, 20, FTW_PHYS) == -1)
                        warn(_("cannot process %s"), path);
                free(path);
+               rootbasesz = 0;
        }
 
        twalk(files, visitor);