touch: add conditional support for -h

Based on a patch by Andy <andy.padavan@gmail.com>

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

diff --git a/coreutils/touch.c b/coreutils/touch.c
index 1216ca202b0ea4efe02be0f10d9c7aacb0d04d6b..293a9689078412731a7540ab7d9b7ee31bf1c0b0 100644 (file)
--- a/coreutils/touch.c
+++ b/coreutils/touch.c
@@ -26,6 +26,14 @@
 //config:        touch is used to create or change the access and/or
 //config:        modification timestamp of specified files.
 //config:
+//config:config FEATURE_TOUCH_NODEREF
+//config:      bool "Add support for -h"
+//config:      default y
+//config:      depends on TOUCH
+//config:      help
+//config:        Enable touch to have the -h option.
+//config:        This requires libc support for lutimes() function.
+//config:
 //config:config FEATURE_TOUCH_SUSV3
 //config:      bool "Add support for SUSV3 features (-d -t -r)"
 //config:      default y
@@ -42,6 +50,9 @@
 //usage:#define touch_full_usage "\n\n"
 //usage:       "Update the last-modified date on the given FILE[s]\n"
 //usage:     "\n       -c      Don't create files"
+//usage:       IF_FEATURE_TOUCH_NODEREF(
+//usage:     "\n       -h      Don't follow links"
+//usage:       )
 //usage:       IF_FEATURE_TOUCH_SUSV3(
 //usage:     "\n       -d DT   Date/time to use"
 //usage:     "\n       -t DT   Date/time to use"
@@ -65,6 +76,7 @@
  *      parse STRING and use it instead of current time
  * -f   (ignored, BSD compat)
  * -m   change only the modification time
+ * -h, --no-dereference
  * -r, --reference=FILE
  *      use this file's times instead of current time
  * -t STAMP
@@ -79,6 +91,13 @@ int touch_main(int argc UNUSED_PARAM, char **argv)
        int fd;
        int status = EXIT_SUCCESS;
        int opts;
+       enum {
+               OPT_c = (1 << 0),
+               OPT_r = (1 << 1) * ENABLE_FEATURE_TOUCH_SUSV3,
+               OPT_d = (1 << 2) * ENABLE_FEATURE_TOUCH_SUSV3,
+               OPT_t = (1 << 3) * ENABLE_FEATURE_TOUCH_SUSV3,
+               OPT_h = (1 << 4) * ENABLE_FEATURE_TOUCH_NODEREF,
+       };
 #if ENABLE_FEATURE_TOUCH_SUSV3
 # if ENABLE_LONG_OPTS
        static const char touch_longopts[] ALIGN1 =
@@ -86,6 +105,7 @@ int touch_main(int argc UNUSED_PARAM, char **argv)
                "no-create\0"         No_argument       "c"
                "reference\0"         Required_argument "r"
                "date\0"              Required_argument "d"
+               IF_FEATURE_TOUCH_NODEREF("no-dereference\0" No_argument "h")
        ;
 # endif
        char *reference_file = NULL;
@@ -105,13 +125,13 @@ int touch_main(int argc UNUSED_PARAM, char **argv)
         * accepted data format differs a bit between -d and -t.
         * We accept the same formats for both */
        opts = getopt32(argv, "c" IF_FEATURE_TOUCH_SUSV3("r:d:t:")
+                               IF_FEATURE_TOUCH_NODEREF("h")
                                /*ignored:*/ "fma"
                                IF_FEATURE_TOUCH_SUSV3(, &reference_file)
                                IF_FEATURE_TOUCH_SUSV3(, &date_str)
                                IF_FEATURE_TOUCH_SUSV3(, &date_str)
        );
 
-       opts &= 1; /* only -c bit is left */
        argv += optind;
        if (!*argv) {
                bb_show_usage();
@@ -121,6 +141,10 @@ int touch_main(int argc UNUSED_PARAM, char **argv)
                struct stat stbuf;
                xstat(reference_file, &stbuf);
                timebuf[1].tv_sec = timebuf[0].tv_sec = stbuf.st_mtime;
+               /* Can use .st_mtim.tv_nsec
+                * (or is it .st_mtimensec?? see date.c)
+                * to set microseconds too.
+                */
        }
 
        if (date_str) {
@@ -141,9 +165,16 @@ int touch_main(int argc UNUSED_PARAM, char **argv)
        }
 
        do {
-               if (utimes(*argv, (reference_file || date_str) ? timebuf : NULL) != 0) {
-                       if (errno == ENOENT) { /* no such file */
-                               if (opts) { /* creation is disabled, so ignore */
+               int result;
+               result = (
+#if ENABLE_FEATURE_TOUCH_NODEREF
+                       (opts & OPT_h) ? lutimes :
+#endif
+                       utimes)(*argv, (reference_file || date_str) ? timebuf : NULL);
+               if (result != 0) {
+                       if (errno == ENOENT) { /* no such file? */
+                               if (opts & OPT_c) {
+                                       /* Creation is disabled, so ignore */
                                        continue;
                                }
                                /* Try to create the file */