New mkswap. Small and simple. Might even work. :)

1 files changed, 29 insertions, 380 deletions

diff --git a/util-linux/mkswap.c b/util-linux/mkswap.c
index 986472e92..9b1e2b5c3 100644
--- a/util-linux/mkswap.c
+++ b/util-linux/mkswap.c
@@ -1,397 +1,46 @@
 /* vi: set sw=4 ts=4: */
-/*
- * mkswap.c - set up a linux swap device
+/* mkswap.c - format swap device (Linux v1 only)
  *
- * (C) 1991 Linus Torvalds. This file may be redistributed as per
- * the Linux copyright.
- */
-
-/*
- * 20.12.91  -  time began. Got VM working yesterday by doing this by hand.
- *
- * Usage: mkswap [-c] [-vN] [-f] device [size-in-blocks]
- *
- *      -c   for readability checking. (Use it unless you are SURE!)
- *      -vN  for swap areas version N. (Only N=0,1 known today.)
- *      -f   for forcing swap creation even if it would smash partition table.
- *
- * The device may be a block device or an image of one, but this isn't
- * enforced (but it's not much fun on a character device :-).
- *
- * Patches from jaggy@purplet.demon.co.uk (Mike Jagdis) to make the
- * size-in-blocks parameter optional added Wed Feb  8 10:33:43 1995.
- *
- * Version 1 swap area code (for kernel 2.1.117), aeb, 981010.
- *
- * Sparc fixes, jj@ultra.linux.cz (Jakub Jelinek), 981201 - mangled by aeb.
- * V1_MAX_PAGES fixes, jj, 990325.
- *
- * 1999-02-22 Arkadiusz Mi¶kiewicz <misiek@misiek.eu.org>
- * - added Native Language Support
+ * Copyright 2006 Rob Landley <rob@landley.net>
  *
- *  from util-linux -- adapted for busybox by
- *  Erik Andersen <andersen@codepoet.org>. I ripped out Native Language
- *  Support, made some stuff smaller, and fitted for life in busybox.
- *
- */
-
-#include "busybox.h"
-#include <unistd.h>
-#include <string.h>
-#include <fcntl.h>
-#include <sys/ioctl.h>                  /* for _IO */
-#include <sys/utsname.h>
-#include <asm/page.h>                   /* for PAGE_SIZE and PAGE_SHIFT */
-                                /* we also get PAGE_SIZE via getpagesize() */
-
-static char *device_name = NULL;
-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;
-#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.
+ * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
  */
-#undef KERNEL_VERSION
-#define KERNEL_VERSION(p,q,r) 1
-#define get_linux_version_code() 1
-#endif
-
-/*
- * The definition of the union swap_header uses the constant PAGE_SIZE.
- * Unfortunately, on some architectures this depends on the hardware model,
- * and can only be found at run time -- we use getpagesize().
- */
-
-static int pagesize;
-static unsigned int *signature_page;
-
-static struct swap_header_v1 {
-        char bootbits[1024];            /* Space for disklabel etc. */
-        unsigned int swap_version;
-        unsigned int last_page;
-        unsigned int nr_badpages;
-        unsigned int padding[125];
-        unsigned int badpages[1];
-} *p;
 
-static inline void init_signature_page(void)
-{
-        pagesize = getpagesize();
+#include <busybox.h>
 
-#ifdef PAGE_SIZE
-        if (pagesize != PAGE_SIZE)
-                bb_error_msg("Assuming pages of size %d", pagesize);
-#endif
-        signature_page = (unsigned int *) xmalloc(pagesize);
-        memset(signature_page, 0, pagesize);
-        p = (struct swap_header_v1 *) signature_page;
-}
-
-static inline void write_signature(char *sig)
+int mkswap_main(int argc, char *argv[])
 {
-        char *sp = (char *) signature_page;
-
-        strncpy(sp + pagesize - 10, sig, 10);
-}
-
-#define V0_MAX_PAGES    (8 * (pagesize - 10))
-/* Before 2.2.0pre9 */
-#define V1_OLD_MAX_PAGES        ((0x7fffffff / pagesize) - 1)
-/* Since 2.2.0pre9:
-   error if nr of pages >= SWP_OFFSET(SWP_ENTRY(0,~0UL))
-   with variations on
-        #define SWP_ENTRY(type,offset) (((type) << 1) | ((offset) << 8))
-        #define SWP_OFFSET(entry) ((entry) >> 8)
-   on the various architectures. Below the result - yuk.
-
-   Machine      pagesize        SWP_ENTRY       SWP_OFFSET      bound+1 oldbound+2
-   i386         2^12            o<<8            e>>8            1<<24   1<<19
-   mips         2^12            o<<15           e>>15           1<<17   1<<19
-   alpha        2^13            o<<40           e>>40           1<<24   1<<18
-   m68k         2^12            o<<12           e>>12           1<<20   1<<19
-   sparc        2^{12,13}       (o&0x3ffff)<<9  (e>>9)&0x3ffff  1<<18   1<<{19,18}
-   sparc64      2^13            o<<13           e>>13           1<<51   1<<18
-   ppc          2^12            o<<8            e>>8            1<<24   1<<19
-   armo         2^{13,14,15}    o<<8            e>>8            1<<24   1<<{18,17,16}
-   armv         2^12            o<<9            e>>9            1<<23   1<<19
-
-   assuming that longs have 64 bits on alpha and sparc64 and 32 bits elsewhere.
+        int fd, pagesize;
+        off_t len;
+        unsigned int hdr[129];
 
-   The bad part is that we need to know this since the kernel will
-   refuse a swap space if it is too large.
-*/
-/* patch from jj - why does this differ from the above? */
-#if defined(__alpha__)
-#define V1_MAX_PAGES           ((1 << 24) - 1)
-#elif defined(__mips__)
-#define V1_MAX_PAGES           ((1 << 17) - 1)
-#elif defined(__sparc_v9__)
-#define V1_MAX_PAGES           ((3 << 29) - 1)
-#elif defined(__sparc__)
-#define V1_MAX_PAGES           (pagesize == 8192 ? ((3 << 29) - 1) : ((1 << 18) - 1))
-#else
-#define V1_MAX_PAGES           V1_OLD_MAX_PAGES
-#endif
-/* man page now says:
-The maximum useful size of a swap area now depends on the architecture.
-It is roughly 2GB on i386, PPC, m68k, ARM, 1GB on sparc, 512MB on mips,
-128GB on alpha and 3TB on sparc64.
-*/
+        // No options supported.
 
-#define MAX_BADPAGES    ((pagesize-1024-128*sizeof(int)-10)/sizeof(int))
-
-static inline void bit_set(unsigned int *addr, unsigned int nr)
-{
-        unsigned int r, m;
-
-        addr += nr / (8 * sizeof(int));
-
-        r = *addr;
-        m = 1 << (nr & (8 * sizeof(int) - 1));
-
-        *addr = r | m;
-}
-
-static int bit_test_and_clear(unsigned int *addr, unsigned int nr)
-{
-        unsigned int r, m;
+        if (argc!=2) bb_show_usage();
 
-        addr += nr / (8 * sizeof(int));
-
-        r = *addr;
-        m = 1 << (nr & (8 * sizeof(int) - 1));
-
-        *addr = r & ~m;
-        return (r & m) != 0;
-}
-
-static void page_ok(int page)
-{
-        if (ENABLE_FEATURE_MKSWAP_V0) {
-                bit_set(signature_page, page);
-        }
-}
-
-static void check_blocks(void)
-{
-        unsigned int current_page;
-        int do_seek = 1;
-        char *buffer;
-
-        buffer = xmalloc(pagesize);
-        current_page = 0;
-        while (current_page < PAGES) {
-                if (!check && version == 0) {
-                        page_ok(current_page++);
-                        continue;
-                }
-                if (do_seek && lseek(DEV, current_page * pagesize, SEEK_SET) !=
-                        current_page * pagesize)
-                        bb_error_msg_and_die("seek failed in check_blocks");
-                if ((do_seek = (pagesize != read(DEV, buffer, pagesize)))) {
-                        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 (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)
-{
-        char ch;
-
-        if (lseek(fd, offset, 0) < 0)
-                return 0;
-        if (read(fd, &ch, 1) < 1)
-                return 0;
-        return 1;
-}
-
-static int find_size(int fd)
-{
-        unsigned int high, low;
-
-        low = 0;
-        for (high = 1; high > 0 && valid_offset(fd, high); high *= 2)
-                low = high;
-        while (low < high - 1) {
-                const int mid = (low + high) / 2;
-
-                if (valid_offset(fd, mid))
-                        low = mid;
-                else
-                        high = mid;
-        }
-        return (low + 1);
-}
-
-/* return size in pages, to avoid integer overflow */
-static inline long get_size(const char *file)
-{
-        int fd;
-        long size;
-
-        fd = bb_xopen3(file, O_RDONLY, 0);
-        if (ioctl(fd, BLKGETSIZE, &size) >= 0) {
-                size /= pagesize / 512;
-        } else {
-                size = find_size(fd) / pagesize;
-        }
-        close(fd);
-        return size;
-}
-
-int mkswap_main(int argc, char **argv)
-{
-        char *tmp;
-        struct stat statbuf;
-        int sz;
-        int maxpages;
-        int goodpages;
-#ifdef __sparc__
-        int force = 0;
-#endif
-
-        init_signature_page();          /* get pagesize */
-
-        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_linux_version_code() < KERNEL_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 {
-                        device_name = argv[0];
-                        sz = get_size(device_name);
-                        argv++;
-                }
-        }
-
-        if (!device_name) {
-                bb_error_msg_and_die("error: Nowhere to set up swap on?");
-        }
-        if (!PAGES) {
-                PAGES = sz;
-        }
-
-        if (!version)
-                maxpages = V0_MAX_PAGES;
-        else if (get_linux_version_code() >= KERNEL_VERSION(2,2,1))
-                maxpages = V1_MAX_PAGES;
-        else {
-                maxpages = V1_OLD_MAX_PAGES;
-                if (maxpages > V1_MAX_PAGES)
-                        maxpages = V1_MAX_PAGES;
-        }
-        if (PAGES > maxpages) {
-                PAGES = maxpages;
-                bb_error_msg("warning: truncating swap area to %ldkB",
-                                PAGES * goodpages);
-        }
-
-        DEV = bb_xopen3(device_name, O_RDWR, 0);
-        if (fstat(DEV, &statbuf) < 0)
-                bb_perror_msg_and_die("%s", device_name);
-        if (!S_ISBLK(statbuf.st_mode))
-                check = 0;
-        else if (statbuf.st_rdev == 0x0300 || statbuf.st_rdev == 0x0340)
-                bb_error_msg_and_die("Will not try to make swapdevice on '%s'", device_name);
+        // Figure out how big the device is and announce our intentions.
+        
+        fd = bb_xopen(argv[1],O_RDWR);
+        len = fdlength(fd);
+        pagesize = getpagesize();
+        printf("Setting up swapspace version 1, size = %ld bytes\n", (long)(len-pagesize));
 
-#ifdef __sparc__
-        if (!force && version == 0) {
-                /* Don't overwrite partition table unless forced */
-                unsigned char *buffer = (unsigned char *) signature_page;
-                unsigned short *q, sum;
+        // Make a header.
 
-                if (read(DEV, buffer, 512) != 512)
-                        bb_error_msg_and_die("fatal: first page unreadable");
-                if (buffer[508] == 0xDA && buffer[509] == 0xBE) {
-                        q = (unsigned short *) (buffer + 510);
-                        for (sum = 0; q >= (unsigned short *) buffer;)
-                                sum ^= *q--;
-                        if (!sum) {
-                                bb_error_msg("Device '%s' contains a valid Sun disklabel.\n"
-"This probably means creating v0 swap would destroy your partition table\n"
-"No swap created. If you really want to create swap v0 on that device, use\n"
-"the -f option to force it.", device_name);
-                                return EXIT_FAILURE;
-                        }
-                }
-        }
-#endif
+        memset(hdr, 0, 129 * sizeof(unsigned int));
+        hdr[0] = 1;
+        hdr[1] = (len / pagesize) - 1;
 
-        if (version == 0 || check)
-                check_blocks();
-        if (version == 0 && !bit_test_and_clear(signature_page, 0))
-                bb_error_msg_and_die("fatal: first page unreadable");
-        if (version == 1) {
-                p->swap_version = version;
-                p->last_page = PAGES - 1;
-                p->nr_badpages = badpages;
-        }
+        // Write the header.  Sync to disk because some kernel versions check
+        // signature on disk (not in cache) during swapon.
 
-        goodpages = PAGES - badpages - 1;
-        if (goodpages <= 0)
-                bb_error_msg_and_die("Unable to set up swap-space: unreadable");
-        printf("Setting up swapspace version %d, size = %ld bytes\n",
-                   version, (long) (goodpages * pagesize));
-        write_signature((version == 0) ? "SWAP-SPACE" : "SWAPSPACE2");
+        xlseek(fd, 1024, SEEK_SET);
+        xwrite(fd, hdr, 129 * sizeof(unsigned int));
+        xlseek(fd, pagesize-10, SEEK_SET);
+        xwrite(fd, "SWAPSPACE2", 10);
+        fsync(fd);
 
-        sz = ((version == 0) ? 0 : 1024); /* offset */
-        if (lseek(DEV, sz, SEEK_SET) != sz)
-                bb_error_msg_and_die("unable to rewind swap-device");
-        goodpages = pagesize - sz; /* cache substraction */
-        if (write(DEV, (char *) signature_page + sz, goodpages)
-                != goodpages)
-                bb_error_msg_and_die("unable to write signature page");
+        if (ENABLE_FEATURE_CLEAN_UP) close(fd);
 
-        /*
-         * A subsequent swapon() will fail if the signature
-         * is not actually on disk. (This is a kernel bug.)
-         */
-        if (fsync(DEV))
-                bb_error_msg_and_die("fsync failed");
-        if (ENABLE_FEATURE_CLEAN_UP) {
-                close(DEV);
-                free(signature_page);
-        }
-        return EXIT_SUCCESS;
+        return 0;
 }