1 files changed, 418 insertions, 0 deletions

diff --git a/busybox/util-linux/mkswap.c b/busybox/util-linux/mkswap.c
new file mode 100644
index 000000000..1fc648f3a
--- /dev/null
+++ b/busybox/util-linux/mkswap.c
@@ -0,0 +1,418 @@
+/* vi: set sw=4 ts=4: */
+/*
+ * mkswap.c - set up a linux swap device
+ *
+ * (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
+ *
+ *  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 <stdio.h>
+#include <unistd.h>
+#include <string.h>
+#include <fcntl.h>
+#include <stdlib.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() */
+#include "busybox.h"
+
+#ifndef _IO
+/* pre-1.3.45 */
+static const int BLKGETSIZE = 0x1260;
+#else
+/* same on i386, m68k, arm; different on alpha, mips, sparc, ppc */
+#define BLKGETSIZE _IO(0x12,96)
+#endif
+
+static char *device_name = NULL;
+static int DEV = -1;
+static long PAGES = 0;
+static int check = 0;
+static int badpages = 0;
+static int version = -1;
+
+#define MAKE_VERSION(p,q,r)     (65536*(p) + 256*(q) + (r))
+
+/*
+ * 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 int *signature_page;
+
+static struct swap_header_v1 {
+        char bootbits[1024];            /* Space for disklabel etc. */
+        unsigned int 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();
+
+#ifdef PAGE_SIZE
+        if (pagesize != PAGE_SIZE)
+                bb_error_msg("Assuming pages of size %d", pagesize);
+#endif
+        signature_page = (int *) xmalloc(pagesize);
+        memset(signature_page, 0, pagesize);
+        p = (struct swap_header_v1 *) signature_page;
+}
+
+static inline void write_signature(char *sig)
+{
+        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.
+
+   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.
+*/
+
+#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;
+
+        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 (version == 0)
+                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)
+{
+        unsigned int current_page;
+        int do_seek = 1;
+        char *buffer;
+
+        buffer = xmalloc(pagesize);
+        current_page = 0;
+        while (current_page < PAGES) {
+                if (!check) {
+                        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)))) {
+                        page_bad(current_page++);
+                        continue;
+                }
+                page_ok(current_page++);
+        }
+        if (badpages == 1)
+                printf("one bad page\n");
+        else if (badpages > 1)
+                printf("%d bad pages\n", badpages);
+}
+
+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 long get_size(const char *file)
+{
+        int fd;
+        long size;
+
+        if ((fd = open(file, O_RDONLY)) < 0)
+                bb_perror_msg_and_die("%s", file);
+        if (ioctl(fd, BLKGETSIZE, &size) >= 0) {
+                int sectors_per_page = pagesize / 512;
+
+                size /= sectors_per_page;
+        } 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;
+        int offset;
+        int force = 0;
+
+        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];
+                } 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();
+                        }
+                }
+        }
+        if (!device_name) {
+                bb_error_msg("error: Nowhere to set up swap on?");
+                bb_show_usage();
+        }
+        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
+        if (!version)
+                maxpages = V0_MAX_PAGES;
+        else if (get_kernel_revision() >= MAKE_VERSION(2, 2, 1))
+                maxpages = V1_MAX_PAGES;
+        else {
+                maxpages = V1_OLD_MAX_PAGES;
+                if (maxpages > V1_MAX_PAGES)
+                        maxpages = V1_MAX_PAGES;
+        }
+#endif
+        if (PAGES > maxpages) {
+                PAGES = maxpages;
+                bb_error_msg("warning: truncating swap area to %ldkB",
+                                PAGES * pagesize / 1024);
+        }
+
+        DEV = open(device_name, O_RDWR);
+        if (DEV < 0 || 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);
+
+#ifdef __sparc__
+        if (!force && version == 0) {
+                /* Don't overwrite partition table unless forced */
+                unsigned char *buffer = (unsigned char *) signature_page;
+                unsigned short *q, sum;
+
+                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
+
+        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->version = version;
+                p->last_page = PAGES - 1;
+                p->nr_badpages = badpages;
+        }
+
+        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");
+
+        offset = ((version == 0) ? 0 : 1024);
+        if (lseek(DEV, offset, SEEK_SET) != offset)
+                bb_error_msg_and_die("unable to rewind swap-device");
+        if (write(DEV, (char *) signature_page + offset, pagesize - offset)
+                != pagesize - offset)
+                bb_error_msg_and_die("unable to write signature page");
+
+        /*
+         * 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");
+        return EXIT_SUCCESS;
+}