- CONFIG_FEATURE_READLINK_FOLLOW readlink -f patch from Colin Watson <cjwatson@debian.org> on busybox mailing list 08/11/04

3 files changed, 39 insertions, 4 deletions

diff --git a/debianutils/Config.in b/debianutils/Config.in
index 7cf7cadb5..f13d56ec7 100644
--- a/debianutils/Config.in
+++ b/debianutils/Config.in
@@ -24,6 +24,13 @@ config CONFIG_READLINK
           This program reads a symbolic link and returns the name
           of the file it points to
 
+config CONFIG_FEATURE_READLINK_FOLLOW
+        bool "  Enable canonicalization by following all symlinks (-f)"
+        default n
+        depends on CONFIG_READLINK
+        help
+          Enable the readlink option (-f).
+
 config CONFIG_RUN_PARTS
         bool "run-parts"
         default n
diff --git a/debianutils/readlink.c b/debianutils/readlink.c
index d8d7e8c2d..90927bb74 100644
--- a/debianutils/readlink.c
+++ b/debianutils/readlink.c
@@ -23,18 +23,38 @@
 #include <errno.h>
 #include <unistd.h>
 #include <stdlib.h>
+#include <getopt.h>
 #include "busybox.h"
 
+#ifdef CONFIG_FEATURE_READLINK_FOLLOW
+# define READLINK_FOLLOW        "f"
+# define READLINK_FLAG_f        (1 << 0)
+#else
+# define READLINK_FOLLOW        ""
+#endif
+
+static const char readlink_options[] = READLINK_FOLLOW;
+
 int readlink_main(int argc, char **argv)
 {
         char *buf = NULL;
+        unsigned long opt = bb_getopt_ulflags(argc, argv, readlink_options);
+#ifdef CONFIG_FEATURE_READLINK_FOLLOW
+        RESERVE_CONFIG_BUFFER(resolved_path, PATH_MAX);
+#endif
 
         /* no options, no getopt */
 
-        if (argc != 2)
+        if (optind + 1 != argc)
                 bb_show_usage();
 
-        buf = xreadlink(argv[1]);
+#ifdef CONFIG_FEATURE_READLINK_FOLLOW
+        if (opt & READLINK_FLAG_f) {
+                buf = realpath(argv[optind], resolved_path);
+        } else
+#endif
+                buf = xreadlink(argv[optind]);
+
         if (!buf)
                 return EXIT_FAILURE;
         puts(buf);
diff --git a/include/usage.h b/include/usage.h
index 377eb10e7..d928a10a3 100644
--- a/include/usage.h
+++ b/include/usage.h
@@ -1985,10 +1985,18 @@
         "\t-s\tSet the system date and time (default).\n" \
         "\t-p\tPrint the date and time."
 
+#ifdef CONFIG_FEATURE_READLINK_FOLLOW
+#define USAGE_READLINK_FOLLOW(a) a
+#else
+#define USAGE_READLINK_FOLLOW(a)
+#endif
+
 #define readlink_trivial_usage \
-        ""
+        USAGE_READLINK_FOLLOW("[-f] ") "FILE"
 #define readlink_full_usage \
-        "Displays the value of a symbolic link."
+        "Displays the value of a symbolic link." \
+        USAGE_READLINK_FOLLOW("\n\nOptions:\n" \
+        "\t-f\tcanonicalize by following all symlinks")
 
 #define realpath_trivial_usage \
         "pathname  ..."