ls: --color now highlights files with capabilities, too

* src/ls.c: [HAVE_CAP] Include <sys/capability.h>.
(has_capability): New function for capability detection.
(print_color_indicator): Colorize file with capability.
* m4/jm-macro.m4: New configure option: --disable-libcap.
Check for libcap usability.
* src/Makefile.am (dir_LDADD, ls_LDADD, ...): Append $(LIB_CAP).
* src/dircolors.c: Update color lists.
* src/dircolors.hin: Mention new CAPABILITY color attribute.
* tests/ls/capability: Test for ls - colorize file with capability.
* tests/Makefile.am (root_tests): Add ls/capability.
* NEWS: Mention the change.

4 files changed, 46 insertions, 7 deletions

diff --git a/src/Makefile.am b/src/Makefile.am
index f464a70a7..7410653ef 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -101,15 +101,15 @@ __LDADD = $(LDADD) $(LIB_EACCESS)
 
 # for clock_gettime and fdatasync
 dd_LDADD = $(LDADD) $(LIB_GETHRXTIME) $(LIB_FDATASYNC)
-dir_LDADD = $(LDADD) $(LIB_CLOCK_GETTIME) $(LIB_SELINUX)
+dir_LDADD = $(LDADD) $(LIB_CLOCK_GETTIME) $(LIB_SELINUX) $(LIB_CAP)
 id_LDADD = $(LDADD) $(LIB_SELINUX)
-ls_LDADD = $(LDADD) $(LIB_CLOCK_GETTIME) $(LIB_SELINUX)
+ls_LDADD = $(LDADD) $(LIB_CLOCK_GETTIME) $(LIB_SELINUX) $(LIB_CAP)
 mktemp_LDADD = $(LDADD) $(LIB_GETHRXTIME)
 pr_LDADD = $(LDADD) $(LIB_CLOCK_GETTIME)
 shred_LDADD = $(LDADD) $(LIB_GETHRXTIME) $(LIB_FDATASYNC)
 shuf_LDADD = $(LDADD) $(LIB_GETHRXTIME)
 tac_LDADD = $(LDADD) $(LIB_CLOCK_GETTIME)
-vdir_LDADD = $(LDADD) $(LIB_CLOCK_GETTIME) $(LIB_SELINUX)
+vdir_LDADD = $(LDADD) $(LIB_CLOCK_GETTIME) $(LIB_SELINUX) $(LIB_CAP)
 
 ## If necessary, add -lm to resolve use of pow in lib/strtod.c.
 sort_LDADD = $(LDADD) $(POW_LIB) $(LIB_GETHRXTIME)
diff --git a/src/dircolors.c b/src/dircolors.c
index 56194f793..79109b934 100644
--- a/src/dircolors.c
+++ b/src/dircolors.c
@@ -63,14 +63,14 @@ static const char *const slack_codes[] =
   "SYMLINK", "ORPHAN", "MISSING", "FIFO", "PIPE", "SOCK", "BLK", "BLOCK",
   "CHR", "CHAR", "DOOR", "EXEC", "LEFT", "LEFTCODE", "RIGHT", "RIGHTCODE",
   "END", "ENDCODE", "SUID", "SETUID", "SGID", "SETGID", "STICKY",
-  "OTHER_WRITABLE", "OWR", "STICKY_OTHER_WRITABLE", "OWT", NULL
+  "OTHER_WRITABLE", "OWR", "STICKY_OTHER_WRITABLE", "OWT", "CAPABILITY", NULL
 };
 
 static const char *const ls_codes[] =
 {
   "no", "no", "fi", "rs", "di", "ln", "ln", "ln", "or", "mi", "pi", "pi",
   "so", "bd", "bd", "cd", "cd", "do", "ex", "lc", "lc", "rc", "rc", "ec", "ec",
-  "su", "su", "sg", "sg", "st", "ow", "ow", "tw", "tw", NULL
+  "su", "su", "sg", "sg", "st", "ow", "ow", "tw", "tw", "ca", NULL
 };
 #define array_len(Array) (sizeof (Array) / sizeof *(Array))
 verify (array_len (slack_codes) == array_len (ls_codes));
diff --git a/src/dircolors.hin b/src/dircolors.hin
index 38914c854..5137cc6f1 100644
--- a/src/dircolors.hin
+++ b/src/dircolors.hin
@@ -77,6 +77,7 @@ CHR 40;33;01	# character device driver
 ORPHAN 40;31;01 # symlink to nonexistent file, or non-stat'able file
 SETUID 37;41	# file that is setuid (u+s)
 SETGID 30;43	# file that is setgid (g+s)
+CAPABILITY 30;41	# file with capability
 STICKY_OTHER_WRITABLE 30;42 # dir that is sticky and other-writable (+t,o+w)
 OTHER_WRITABLE 34;42 # dir that is other-writable (o+w) and not sticky
 STICKY 37;44	# dir with the sticky bit set (+t) and not other-writable
diff --git a/src/ls.c b/src/ls.c
index a661c063f..fd32730e4 100644
--- a/src/ls.c
+++ b/src/ls.c
@@ -38,6 +38,10 @@
 #include <config.h>
 #include <sys/types.h>
 
+#ifdef HAVE_CAP
+# include <sys/capability.h>
+#endif
+
 #if HAVE_TERMIOS_H
 # include <termios.h>
 #endif
@@ -513,14 +517,14 @@ enum indicator_no
     C_LEFT, C_RIGHT, C_END, C_RESET, C_NORM, C_FILE, C_DIR, C_LINK,
     C_FIFO, C_SOCK,
     C_BLK, C_CHR, C_MISSING, C_ORPHAN, C_EXEC, C_DOOR, C_SETUID, C_SETGID,
-    C_STICKY, C_OTHER_WRITABLE, C_STICKY_OTHER_WRITABLE
+    C_STICKY, C_OTHER_WRITABLE, C_STICKY_OTHER_WRITABLE, C_CAP
   };
 
 static const char *const indicator_name[]=
   {
     "lc", "rc", "ec", "rs", "no", "fi", "di", "ln", "pi", "so",
     "bd", "cd", "mi", "or", "ex", "do", "su", "sg", "st",
-    "ow", "tw", NULL
+    "ow", "tw", "ca", NULL
   };
 
 struct color_ext_type
@@ -553,6 +557,7 @@ static struct bin_str color_indicator[] =
     { LEN_STR_PAIR ("37;44") },		/* st: sticky: black on blue */
     { LEN_STR_PAIR ("34;42") },		/* ow: other-writable: blue on green */
     { LEN_STR_PAIR ("30;42") },		/* tw: ow w/ sticky: black on green */
+    { LEN_STR_PAIR ("30;41") },		/* capability: black on red */
   };
 
 /* FIXME: comment  */
@@ -3910,6 +3915,37 @@ print_type_indicator (bool stat_ok, mode_t mode, enum filetype type)
     DIRED_PUTCHAR (c);
 }
 
+#ifdef HAVE_CAP
+/* Return true if NAME has a capability (see linux/capability.h) */
+static bool
+has_capability (char const *name)
+{
+  char *result;
+  bool has_cap;
+
+  cap_t cap_d = cap_get_file (name);
+  if (cap_d == NULL)
+    return false;
+
+  result = cap_to_text (cap_d, NULL);
+  cap_free (cap_d);
+  if (!result)
+    return false;
+
+  /* check if human-readable capability string is empty */
+  has_cap = !!*result;
+
+  cap_free (result);
+  return has_cap;
+}
+#else
+static bool
+has_capability (char const *name)
+{
+  return false;
+}
+#endif
+
 /* Returns whether any color sequence was printed. */
 static bool
 print_color_indicator (const char *name, mode_t mode, int linkok,
@@ -3937,6 +3973,8 @@ print_color_indicator (const char *name, mode_t mode, int linkok,
 	    type = C_SETUID;
 	  else if ((mode & S_ISGID) != 0)
 	    type = C_SETGID;
+	  else if (has_capability (name))
+	    type = C_CAP;
 	  else if ((mode & S_IXUGO) != 0)
 	    type = C_EXEC;
 	}