- shrink mkswap and make v0 support optional. Thanks also to Tito for his ideas.

  http://busybox.net/lists/busybox/2006-March/019326.html

   2137	      8	     28	   2173	    87d	util-linux/mkswap.o.orig
   1890	      8	     28	   1926	    786	util-linux/mkswap.o.v0+v1
   1560	      4	     28	   1592	    638	util-linux/mkswap.o.v1

2 files changed, 83 insertions, 79 deletions

diff --git a/util-linux/Config.in b/util-linux/Config.in
index 28292bd40..33567d9a9 100644
--- a/util-linux/Config.in
+++ b/util-linux/Config.in
@@ -288,6 +288,16 @@ config CONFIG_MKSWAP
           Once you have created swap space using 'mkswap' you need to enable
           the swap space using the 'swapon' utility.
 
+config CONFIG_FEATURE_MKSWAP_V0
+        bool "  version 0 support"
+        default n
+        depends on CONFIG_MKSWAP
+#       depends on CONFIG_MKSWAP && CONFIG_DEPRECATED
+        help
+          Enable support for the old v0 style.
+          If your kernel is older than 2.1.117, then v0 support is the
+          only option.
+
 config CONFIG_MORE
         bool "more"
         default n
diff --git a/util-linux/mkswap.c b/util-linux/mkswap.c
index 4107329a6..ce123e502 100644
--- a/util-linux/mkswap.c
+++ b/util-linux/mkswap.c
@@ -59,9 +59,17 @@ static int DEV = -1;
 static long PAGES = 0;
 static int check = 0;
 static int badpages = 0;
+#if ENABLE_FEATURE_MKSWAP_V0
 static int version = -1;
-
 #define MAKE_VERSION(p,q,r)     (65536*(p) + 256*(q) + (r))
+#else
+#define version 1
+/* and make sure that we optimize away anything which would deal with checking
+ * the kernel revision as we have v1 support only anyway.
+ */
+#define MAKE_VERSION(p,q,r) 1
+#define get_kernel_revision() 1
+#endif
 
 /*
  * The definition of the union swap_header uses the constant PAGE_SIZE.
@@ -74,7 +82,7 @@ static unsigned int *signature_page;
 
 static struct swap_header_v1 {
         char bootbits[1024];            /* Space for disklabel etc. */
-        unsigned int version;
+        unsigned int swap_version;
         unsigned int last_page;
         unsigned int nr_badpages;
         unsigned int padding[125];
@@ -172,23 +180,11 @@ static int bit_test_and_clear(unsigned int *addr, unsigned int nr)
         return (r & m) != 0;
 }
 
-
 static void page_ok(int page)
 {
-        if (version == 0)
+        if (ENABLE_FEATURE_MKSWAP_V0) {
                 bit_set(signature_page, page);
-}
-
-static inline void page_bad(int page)
-{
-        if (version == 0)
-                bit_test_and_clear(signature_page, page);
-        else {
-                if (badpages == MAX_BADPAGES)
-                        bb_error_msg_and_die("too many bad pages");
-                p->badpages[badpages] = page;
         }
-        badpages++;
 }
 
 static void check_blocks(void)
@@ -200,7 +196,7 @@ static void check_blocks(void)
         buffer = xmalloc(pagesize);
         current_page = 0;
         while (current_page < PAGES) {
-                if (!check) {
+                if (!check && version == 0) {
                         page_ok(current_page++);
                         continue;
                 }
@@ -208,15 +204,23 @@ static void check_blocks(void)
                         current_page * pagesize)
                         bb_error_msg_and_die("seek failed in check_blocks");
                 if ((do_seek = (pagesize != read(DEV, buffer, pagesize)))) {
-                        page_bad(current_page++);
+                        current_page++;
+                        if (version == 0)
+                                bit_test_and_clear(signature_page, current_page);
+                        else {
+                                if (badpages == MAX_BADPAGES)
+                                        bb_error_msg_and_die("too many bad pages");
+                                p->badpages[badpages] = current_page;
+                        }
+                        badpages++;
                         continue;
                 }
                 page_ok(current_page++);
         }
-        if (badpages == 1)
-                printf("one bad page\n");
-        else if (badpages > 1)
-                printf("%d bad pages\n", badpages);
+        if (ENABLE_FEATURE_CLEAN_UP)
+                free(buffer);
+        if (badpages > 0)
+                printf("%d bad page%s\n", badpages, (badpages==1)?"":"s");
 }
 
 static long valid_offset(int fd, int offset)
@@ -249,17 +253,15 @@ static int find_size(int fd)
 }
 
 /* return size in pages, to avoid integer overflow */
-static long get_size(const char *file)
+static inline long get_size(const char *file)
 {
         int fd;
         long size;
 
-        if ((fd = open(file, O_RDONLY)) < 0)
+        if ((fd = open(file, O_RDONLY)) < 0) /* TODO: bb_xopen3 */
                 bb_perror_msg_and_die("%s", file);
         if (ioctl(fd, BLKGETSIZE, &size) >= 0) {
-                int sectors_per_page = pagesize / 512;
-
-                size /= sectors_per_page;
+                size /= pagesize / 512;
         } else {
                 size = find_size(fd) / pagesize;
         }
@@ -274,66 +276,53 @@ int mkswap_main(int argc, char **argv)
         int sz;
         int maxpages;
         int goodpages;
-        int offset;
+#ifdef __sparc__
         int force = 0;
+#endif
 
         init_signature_page();          /* get pagesize */
 
-        while (argc-- > 1) {
-                argv++;
-                if (argv[0][0] != '-') {
-                        if (device_name) {
-                                int blocks_per_page = pagesize / 1024;
-
-                                PAGES = strtol(argv[0], &tmp, 0) / blocks_per_page;
-                                if (*tmp)
-                                        bb_show_usage();
-                        } else
-                                device_name = argv[0];
+        bb_opt_complementally = "?"; /* call bb_show_usage internally */
+        sz = bb_getopt_ulflags(argc, argv, "+cfv:", &tmp);
+        if (sz & 1)
+                check = 1;
+#ifdef __sparc__
+        if (sz & 2)
+                force = 1;
+#endif
+#if ENABLE_FEATURE_MKSWAP_V0
+        if (sz & 4) {
+                version = bb_xgetlarg(tmp, 10, 0, 1);
+        } else {
+                if (get_kernel_revision() < MAKE_VERSION(2, 1, 117))
+                        version = 0;
+                else
+                        version = 1;
+        }
+#endif
+
+        argv += optind;
+        argc -= optind;
+
+        goodpages = pagesize / 1024; /* cache division */
+        while (argc--) {
+                if (device_name) {
+                        PAGES = bb_xgetlarg(argv[0], 0, 10, sz * goodpages) / goodpages;
+                        argc = 0; /* ignore any surplus args.. */
                 } else {
-                        switch (argv[0][1]) {
-                        case 'c':
-                                check = 1;
-                                break;
-                        case 'f':
-                                force = 1;
-                                break;
-                        case 'v':
-                                version = atoi(argv[0] + 2);
-                                break;
-                        default:
-                                bb_show_usage();
-                        }
+                        device_name = argv[0];
+                        sz = get_size(device_name);
+                        argv++;
                 }
         }
+
         if (!device_name) {
-                bb_error_msg("error: Nowhere to set up swap on?");
-                bb_show_usage();
+                bb_error_msg_and_die("error: Nowhere to set up swap on?");
         }
-        sz = get_size(device_name);
         if (!PAGES) {
                 PAGES = sz;
-        } else if (PAGES > sz && !force) {
-                bb_error_msg("error: size %ld is larger than device size %d",
-                                PAGES * (pagesize / 1024), sz * (pagesize / 1024));
-                return EXIT_FAILURE;
         }
 
-        if (version == -1) {
-                if (get_kernel_revision() < MAKE_VERSION(2, 1, 117))
-                        version = 0;
-                else
-                        version = 1;
-        }
-        if (version != 0 && version != 1) {
-                bb_error_msg("error: unknown version %d", version);
-                bb_show_usage();
-        }
-        if (PAGES < 10) {
-                bb_error_msg("error: swap area needs to be at least %ldkB",
-                                (long) (10 * pagesize / 1024));
-                bb_show_usage();
-        }
 #if 0
         maxpages = ((version == 0) ? V0_MAX_PAGES : V1_MAX_PAGES);
 #else
@@ -350,7 +339,7 @@ int mkswap_main(int argc, char **argv)
         if (PAGES > maxpages) {
                 PAGES = maxpages;
                 bb_error_msg("warning: truncating swap area to %ldkB",
-                                PAGES * pagesize / 1024);
+                                PAGES * goodpages);
         }
 
         DEV = open(device_name, O_RDWR);
@@ -389,7 +378,7 @@ int mkswap_main(int argc, char **argv)
         if (version == 0 && !bit_test_and_clear(signature_page, 0))
                 bb_error_msg_and_die("fatal: first page unreadable");
         if (version == 1) {
-                p->version = version;
+                p->swap_version = version;
                 p->last_page = PAGES - 1;
                 p->nr_badpages = badpages;
         }
@@ -401,11 +390,12 @@ int mkswap_main(int argc, char **argv)
                    version, (long) (goodpages * pagesize));
         write_signature((version == 0) ? "SWAP-SPACE" : "SWAPSPACE2");
 
-        offset = ((version == 0) ? 0 : 1024);
-        if (lseek(DEV, offset, SEEK_SET) != offset)
+        sz = ((version == 0) ? 0 : 1024); /* offset */
+        if (lseek(DEV, sz, SEEK_SET) != sz)
                 bb_error_msg_and_die("unable to rewind swap-device");
-        if (write(DEV, (char *) signature_page + offset, pagesize - offset)
-                != pagesize - offset)
+        goodpages = pagesize - sz; /* cache substraction */
+        if (write(DEV, (char *) signature_page + sz, goodpages)
+                != goodpages)
                 bb_error_msg_and_die("unable to write signature page");
 
         /*
@@ -414,5 +404,9 @@ int mkswap_main(int argc, char **argv)
          */
         if (fsync(DEV))
                 bb_error_msg_and_die("fsync failed");
+        if (ENABLE_FEATURE_CLEAN_UP) {
+                close(DEV);
+                free(signature_page);
+        }
         return EXIT_SUCCESS;
 }