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-rw-r--r--mkswap.c448
1 files changed, 332 insertions, 116 deletions
diff --git a/mkswap.c b/mkswap.c
index 8c0c4dec7..fceeb28dd 100644
--- a/mkswap.c
+++ b/mkswap.c
@@ -1,4 +1,3 @@
-#include "internal.h"
/*
* mkswap.c - set up a linux swap device
*
@@ -9,51 +8,170 @@
/*
* 20.12.91 - time began. Got VM working yesterday by doing this by hand.
*
- * Usage: mkswap [-c] device [size-in-blocks]
+ * Usage: mkswap [-c] [-vN] [-f] device [size-in-blocks]
*
- * -c for readablility checking (use it unless you are SURE!)
+ * -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 a image of one, but this isn't
+ * 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 <andersee@debian.org>. I ripped out Native Language
+ * Support, made some stuff smaller, and fitted for life in busybox.
+ *
*/
+#include "internal.h"
#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 <sys/stat.h>
-#include <sys/ioctl.h>
+#include <asm/page.h> /* for PAGE_SIZE and PAGE_SHIFT */
+ /* we also get PAGE_SIZE via getpagesize() */
-#include <asm/page.h>
-#include <linux/fs.h>
-#ifndef __linux__
-# define volatile
-#endif
+static const char mkswap_usage[] = "mkswap [-c] [-v0|-v1] device [block-count]\n"
+"Prepare a disk partition to be used as a swap partition.\n\n"
+"\t-c\tCheck for read-ability.\n"
+"\t-v0\tMake version 0 swap [max 128 Megs].\n"
+"\t-v1\tMake version 1 swap [big!] (default for kernels > 2.1.117).\n"
+"\tblock-count\tNumber of block to use (default is entire partition).\n";
-#define TEST_BUFFER_PAGES 8
-const char mkswap_usage[] = "mkswap [-c] partition [block-count]\n"
-"\n"
-"\tPrepare a disk partition to be used as a swap partition.\n"
-"\tThe default block count is the size of the entire partition.\n"
-"\n"
-"\t-c:\tCheck for read-ability.\n"
-"\tblock-count\tUse only this many blocks.\n";
+#ifndef _IO
+/* pre-1.3.45 */
+#define BLKGETSIZE 0x1260
+#else
+/* same on i386, m68k, arm; different on alpha, mips, sparc, ppc */
+#define BLKGETSIZE _IO(0x12,96)
+#endif
-static const char * program_name = "mkswap";
-static const char * device_name = NULL;
+static char * program_name = "mkswap";
+static char * device_name = NULL;
static int DEV = -1;
static long PAGES = 0;
-static int do_check = 0;
+static int check = 0;
static int badpages = 0;
+static int version = -1;
+
+#define MAKE_VERSION(p,q,r) (65536*(p) + 256*(q) + (r))
+
+static int
+linux_version_code(void) {
+ struct utsname my_utsname;
+ int p, q, r;
+
+ if (uname(&my_utsname) == 0) {
+ p = atoi(strtok(my_utsname.release, "."));
+ q = atoi(strtok(NULL, "."));
+ r = atoi(strtok(NULL, "."));
+ return MAKE_VERSION(p,q,r);
+ }
+ return 0;
+}
+
+/*
+ * 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;
+
+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 void
+init_signature_page() {
+ pagesize = getpagesize();
+
+#ifdef PAGE_SIZE
+ if (pagesize != PAGE_SIZE)
+ fprintf(stderr, "Assuming pages of size %d\n", pagesize);
+#endif
+ signature_page = (int *) malloc(pagesize);
+ memset(signature_page,0,pagesize);
+ p = (struct swap_header_v1 *) signature_page;
+}
+static void
+write_signature(char *sig) {
+ char *sp = (char *) signature_page;
-static long bit_test_and_set (unsigned int *addr, unsigned int nr)
+ 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 void bit_set (unsigned int *addr, unsigned int nr)
{
unsigned int r, m;
@@ -61,7 +179,6 @@ static long bit_test_and_set (unsigned int *addr, unsigned int nr)
r = *addr;
m = 1 << (nr & (8 * sizeof(int) - 1));
*addr = r | m;
- return (r & m) != 0;
}
static int bit_test_and_clear (unsigned int *addr, unsigned int nr)
@@ -75,47 +192,59 @@ static int bit_test_and_clear (unsigned int *addr, unsigned int nr)
return (r & m) != 0;
}
-/*
- * Volatile to let gcc know that this doesn't return. When trying
- * to compile this under minix, volatile gives a warning, as
- * exit() isn't defined as volatile under minix.
- */
-volatile void fatal_error(const char * fmt_string)
-{
- fprintf(stderr,fmt_string,program_name,device_name);
- exit(FALSE);
+
+void
+die(const char *str) {
+ fprintf(stderr, "%s: %s\n", program_name, str);
+ exit( FALSE);
}
-#define die(str) fatal_error("%s: " str "\n")
+void
+page_ok(int page) {
+ if (version==0)
+ bit_set(signature_page, page);
+}
-static void check_blocks(int * signature_page)
-{
+void
+page_bad(int page) {
+ if (version == 0)
+ bit_test_and_clear(signature_page, page);
+ else {
+ if (badpages == MAX_BADPAGES)
+ die("too many bad pages");
+ p->badpages[badpages] = page;
+ }
+ badpages++;
+}
+
+void
+check_blocks(void) {
unsigned int current_page;
int do_seek = 1;
- char buffer[PAGE_SIZE];
+ char *buffer;
+ buffer = malloc(pagesize);
+ if (!buffer)
+ die("Out of memory");
current_page = 0;
while (current_page < PAGES) {
- if (!do_check) {
- bit_test_and_set(signature_page,current_page++);
+ if (!check) {
+ page_ok(current_page++);
continue;
- } else {
- printf("\r%d", current_page);
}
- if (do_seek && lseek(DEV,current_page*PAGE_SIZE,SEEK_SET) !=
- current_page*PAGE_SIZE)
+ if (do_seek && lseek(DEV,current_page*pagesize,SEEK_SET) !=
+ current_page*pagesize)
die("seek failed in check_blocks");
- if ( (do_seek = (PAGE_SIZE != read(DEV, buffer, PAGE_SIZE))) ) {
- bit_test_and_clear(signature_page,current_page++);
- badpages++;
+ if ((do_seek = (pagesize != read(DEV, buffer, pagesize)))) {
+ page_bad(current_page++);
continue;
}
- bit_test_and_set(signature_page,current_page++);
+ page_ok(current_page++);
}
- if (do_check)
- printf("\n");
- if (badpages)
- printf("%d bad page%s\n",badpages,(badpages>1)?"s":"");
+ 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)
@@ -129,12 +258,13 @@ static long valid_offset (int fd, int offset)
return 1;
}
-static int count_blocks (int fd)
+static int
+find_size (int fd)
{
- int high, low;
+ unsigned int high, low;
low = 0;
- for (high = 1; valid_offset (fd, high); high *= 2)
+ for (high = 1; high > 0 && valid_offset (fd, high); high *= 2)
low = high;
while (low < high - 1)
{
@@ -145,108 +275,194 @@ static int count_blocks (int fd)
else
high = mid;
}
- valid_offset (fd, 0);
return (low + 1);
}
-static int get_size(const char *file)
+/* return size in pages, to avoid integer overflow */
+static long
+get_size(const char *file)
{
int fd;
- int size;
+ long size;
- fd = open(file, O_RDWR);
+ fd = open(file, O_RDONLY);
if (fd < 0) {
perror(file);
exit(1);
}
if (ioctl(fd, BLKGETSIZE, &size) >= 0) {
- close(fd);
- return (size * 512);
+ int sectors_per_page = pagesize/512;
+ size /= sectors_per_page;
+ } else {
+ size = find_size(fd) / pagesize;
}
-
- size = count_blocks(fd);
close(fd);
return size;
}
-int
-mkswap(const char *device_name, int pages, int check)
- {
+int mkswap_main(int argc, char ** argv)
+{
+ char * tmp;
struct stat statbuf;
+ int sz;
+ int maxpages;
int goodpages;
- int signature_page[PAGE_SIZE/sizeof(int)];
+ int offset;
+ int force = 0;
- PAGES = pages;
- do_check = check;
+ if (argc && *argv)
+ program_name = *argv;
- memset(signature_page,0,PAGE_SIZE);
+ init_signature_page(); /* get pagesize */
- if (device_name && !PAGES) {
- PAGES = get_size(device_name) / PAGE_SIZE;
+ 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)
+ usage( mkswap_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:
+ usage( mkswap_usage);
+ }
+ }
+ }
+ if (!device_name) {
+ fprintf(stderr,
+ "%s: error: Nowhere to set up swap on?\n",
+ program_name);
+ usage( mkswap_usage);
}
- if (!device_name || PAGES<10) {
+ sz = get_size(device_name);
+ if (!PAGES) {
+ PAGES = sz;
+ } else if (PAGES > sz && !force) {
+ fprintf(stderr,
+ "%s: error: "
+ "size %ld is larger than device size %d\n",
+ program_name,
+ PAGES*(pagesize/1024), sz*(pagesize/1024));
+ exit( FALSE);
+ }
+
+ if (version == -1) {
+ if (PAGES <= V0_MAX_PAGES)
+ version = 0;
+ else if (linux_version_code() < MAKE_VERSION(2,1,117))
+ version = 0;
+ else if (pagesize < 2048)
+ version = 0;
+ else
+ version = 1;
+ }
+ if (version != 0 && version != 1) {
+ fprintf(stderr, "%s: error: unknown version %d\n",
+ program_name, version);
+ usage( mkswap_usage);
+ }
+ if (PAGES < 10) {
fprintf(stderr,
"%s: error: swap area needs to be at least %ldkB\n",
- program_name, 10 * PAGE_SIZE / 1024);
- /* usage(mkswap_usage); */
- exit(1);
+ program_name, (long)(10 * pagesize / 1024));
+ usage( mkswap_usage);
+ }
+#if 0
+ maxpages = ((version == 0) ? V0_MAX_PAGES : V1_MAX_PAGES);
+#else
+ if (!version)
+ maxpages = V0_MAX_PAGES;
+ else if (linux_version_code() >= MAKE_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 > 8 * (PAGE_SIZE - 10)) {
- PAGES = 8 * (PAGE_SIZE - 10);
+#endif
+ if (PAGES > maxpages) {
+ PAGES = maxpages;
fprintf(stderr, "%s: warning: truncating swap area to %ldkB\n",
- program_name, PAGES * PAGE_SIZE / 1024);
+ program_name, PAGES * pagesize / 1024);
}
+
DEV = open(device_name,O_RDWR);
if (DEV < 0 || fstat(DEV, &statbuf) < 0) {
perror(device_name);
- exit(1);
+ exit( FALSE);
}
if (!S_ISBLK(statbuf.st_mode))
- do_check=0;
+ check=0;
else if (statbuf.st_rdev == 0x0300 || statbuf.st_rdev == 0x0340)
die("Will not try to make swapdevice on '%s'");
- check_blocks(signature_page);
- if (!bit_test_and_clear(signature_page,0))
+
+#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)
+ 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) {
+ fprintf(stderr, "\
+%s: 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.\n",
+ program_name, device_name);
+ exit( FALSE);
+ }
+ }
+ }
+#endif
+
+ if (version == 0 || check)
+ check_blocks();
+ if (version == 0 && !bit_test_and_clear(signature_page,0))
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)
die("Unable to set up swap-space: unreadable");
- printf("Setting up swapspace, size = %ld bytes\n",goodpages*PAGE_SIZE);
- strncpy((char*)signature_page+PAGE_SIZE-10,"SWAP-SPACE",10);
- if (lseek(DEV, 0, SEEK_SET))
+ 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)
die("unable to rewind swap-device");
- if (PAGE_SIZE != write(DEV, signature_page, PAGE_SIZE))
+ if (write(DEV,(char*)signature_page+offset, pagesize-offset)
+ != pagesize-offset)
die("unable to write signature page");
- close(DEV);
- return (TRUE);
-}
-
-int mkswap_main(int argc, char ** argv)
-{
- char * tmp;
- long int pages=0;
- int check=0;
-
- if (argc && *argv)
- program_name = *argv;
- while (argc > 1) {
- argv++;
- argc--;
- if (argv[0][0] != '-')
- if (device_name) {
- pages = strtol(argv[0],&tmp,0)>>(PAGE_SHIFT-10);
- if (*tmp) {
- usage (mkswap_usage);
- }
- } else
- device_name = argv[0];
- else while (*++argv[0])
- switch (argv[0][0]) {
- case 'c': check=1; break;
- default: usage (mkswap_usage);
- exit( TRUE);
- }
- }
- exit( mkswap(device_name, pages, check));
+ /*
+ * A subsequent swapon() will fail if the signature
+ * is not actually on disk. (This is a kernel bug.)
+ */
+ if (fsync(DEV))
+ die("fsync failed");
+ exit ( TRUE);
}
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