df: add -i (conditional on CONFIG)

uasge: trim a bit

coreutils/Config.in

@@ -135,6 +135,13 @@ config DF
 	  df reports the amount of disk space used and available
 	  on filesystems.
 
+config FEATURE_DF_INODE
+	bool "Enable -i (inode information)"
+	default n
+	depends on DF
+	help
+	  This option enables support for df -i.
+
 config DIRNAME
 	bool "dirname"
 	default n

coreutils/df.c

@@ -45,9 +45,14 @@ int df_main(int argc, char **argv)
 	/* default display is kilobytes */
 	const char *disp_units_hdr = "1k-blocks";
 
+	enum {
+		OPT_INODE = (ENABLE_FEATURE_HUMAN_READABLE ? (1 << 3) : (1 << 1))
+		            * ENABLE_FEATURE_DF_INODE
+	};
+
 #if ENABLE_FEATURE_HUMAN_READABLE
 	opt_complementary = "h-km:k-hm:m-hk";
-	opt = getopt32(argv, "hmk");
+	opt = getopt32(argv, "hmk" USE_FEATURE_DF_INODE("i"));
 	if (opt & 1) {
 		df_disp_hr = 0;
 		disp_units_hdr = "     Size";
@@ -56,8 +61,11 @@ int df_main(int argc, char **argv)
 		df_disp_hr = 1024*1024;
 		disp_units_hdr = "1M-blocks";
 	}
+	if (opt & OPT_INODE) {
+		disp_units_hdr = "   Inodes";
+	}
 #else
-	opt = getopt32(argv, "k");
+	opt = getopt32(argv, "k" USE_FEATURE_DF_INODE("i"));
 #endif
 
 	printf("Filesystem%11s%-15sUsed Available Use%% Mounted on\n",
@@ -105,6 +113,15 @@ int df_main(int argc, char **argv)
 		}
 
 		if ((s.f_blocks > 0) || !mount_table) {
+			if (opt & OPT_INODE) {
+				s.f_blocks = s.f_files;
+				s.f_bavail = s.f_bfree = s.f_ffree;
+				s.f_bsize = 1;
+#if ENABLE_FEATURE_HUMAN_READABLE
+				if (df_disp_hr)
+					df_disp_hr = 1;
+#endif
+			}
 			blocks_used = s.f_blocks - s.f_bfree;
 			blocks_percent_used = 0;
 			if (blocks_used + s.f_bavail) {
@@ -115,7 +132,8 @@ int df_main(int argc, char **argv)
 
 			if (strcmp(device, "rootfs") == 0) {
 				continue;
-			} else if (strcmp(device, "/dev/root") == 0) {
+			}
+			if (strcmp(device, "/dev/root") == 0) {
 				/* Adjusts device to be the real root device,
 				* or leaves device alone if it can't find it */
 				device = find_block_device("/");

include/usage.h

@@ -630,18 +630,28 @@
        "\n		and processing synthetic REGISTER events," \
        "\n		do not poll for events")
 
+/* -k is accepted but ignored for !HUMAN_READABLE,
+ * but we won't mention this (unimportant) */
+#if ENABLE_FEATURE_HUMAN_READABLE || ENABLE_FEATURE_DF_INODE
+#define DF_HAS_OPTIONS(x) x
+#else
+#define DF_HAS_OPTIONS(x)
+#endif
 #define df_trivial_usage \
-       "[-" USE_FEATURE_HUMAN_READABLE("hm") "k] [FILESYSTEM ...]"
+	DF_HAS_OPTIONS("[-") \
+	USE_FEATURE_HUMAN_READABLE("hmk") USE_FEATURE_DF_INODE("i") \
+	DF_HAS_OPTIONS("] ") "[FILESYSTEM...]"
 #define df_full_usage \
-       "Print the filesystem space used and space available" \
+       "Print filesystem usage statistics" \
+	DF_HAS_OPTIONS("\n\nOptions:") \
 	USE_FEATURE_HUMAN_READABLE( \
-       "\n\nOptions control size display:" \
        "\n	-h	Human readable (e.g. 1K 243M 2G)" \
        "\n	-m	1024*1024 blocks" \
-       "\n	-k	1024 blocks") \
+       "\n	-k	1024 blocks" \
-	SKIP_FEATURE_HUMAN_READABLE( \
+	) \
-       "\n\nOptions:" \
+	USE_FEATURE_DF_INODE( \
-       "\n	-k	Ignored")
+       "\n	-i	Inodes" \
+	)
 #define df_example_usage \
        "$ df\n" \
        "Filesystem           1k-blocks      Used Available Use% Mounted on\n" \