minix/commands/simple/mkswap.c
2005-04-21 14:53:53 +00:00

197 lines
4.9 KiB
C
Executable file

/* mkswap 1.0 - Initialize a swap partition or file
* Author: Kees J. Bot
* 6 Jan 2001
*/
#define nil ((void*)0)
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <unistd.h>
#include <dirent.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/ioctl.h>
#include <minix/config.h>
#include <minix/const.h>
#include <minix/type.h>
#include <minix/u64.h>
#include <minix/partition.h>
#include <minix/swap.h>
#include <servers/fs/const.h>
#include <servers/fs/type.h>
#include <servers/fs/super.h>
static void usage(void)
{
fprintf(stderr, "Usage: mkswap [-f] device-or-file [size[km]]\n");
exit(1);
}
int main(int argc, char **argv)
{
int first;
int i;
char *file;
unsigned long offset, size, devsize;
int fd;
struct stat st;
ssize_t r;
struct super_block super;
swap_hdr_t swap_hdr;
static u8_t block[MAX_BLOCK_SIZE];
first= 0;
i= 1;
while (i < argc && argv[i][0] == '-') {
char *opt= argv[i++]+1;
if (opt[0] == '-' && opt[1] == 0) break; /* -- */
while (*opt != 0) switch (*opt++) {
case 'f': first= 1; break;
default: usage();
}
}
if (i == argc) usage();
file= argv[i++];
size= 0;
if (i < argc) {
char *end;
unsigned long m;
size= strtoul(argv[i], &end, 10);
if (end == argv[i]) usage();
m= 1024;
if (*end != 0) {
switch (*end) {
case 'm': case 'M': m *= 1024; /*FALL THROUGH*/
case 'k': case 'K': end++; break;
}
}
if (*end != 0 || size == -1
|| (size * m) / m != size || (size *= m) <= SWAP_OFFSET
) {
fprintf(stderr, "mkswap: %s: Bad size\n", argv[i]);
exit(1);
}
i++;
}
if (i != argc) usage();
/* Open the device or file. */
if ((fd= open(file, O_RDWR | O_CREAT | O_TRUNC, 0600)) < 0) {
fprintf(stderr, "mkswap: Can't open %s: %s\n", file, strerror(errno));
exit(1);
}
/* File or device? */
(void) fstat(fd, &st);
if (S_ISBLK(st.st_mode) || S_ISCHR(st.st_mode)) {
struct partition part;
/* How big is the partition? */
if (ioctl(fd, DIOCGETP, &part) < 0) {
fprintf(stderr, "mkswap: Can't determine the size of %s: %s\n",
file, strerror(errno));
exit(1);
}
devsize= cv64ul(part.size);
offset= 0;
if (!first) {
/* Is there a file system? */
r= -1;
if (lseek(fd, SUPER_BLOCK_BYTES, SEEK_SET) == -1
|| (r= read(fd, block, STATIC_BLOCK_SIZE)) < STATIC_BLOCK_SIZE
) {
fprintf(stderr, "mkswap: %s: %s\n",
file, r >= 0 ? "End of file" : strerror(errno));
exit(1);
}
memcpy(&super, block, sizeof(super));
if (super.s_magic == SUPER_MAGIC) {
offset= (unsigned long) super.s_nzones * STATIC_BLOCK_SIZE;
} else
if (super.s_magic == SUPER_V2) {
offset= (unsigned long) super.s_zones * STATIC_BLOCK_SIZE;
} else if (super.s_magic == SUPER_V3) {
offset= (unsigned long) super.s_zones * super.s_block_size;
} else {
first= 1;
}
}
if (size == 0) size= devsize - offset;
if (size == 0 || offset + size > devsize) {
fprintf(stderr, "mkswap: There is no room on %s for ", file);
if (size > 0) fprintf(stderr, "%lu kilobytes of ", size/1024);
fprintf(stderr, "swapspace\n");
if (offset > 0) {
fprintf(stderr, "(Use the -f flag to wipe the file system)\n");
}
exit(1);
}
} else
if (S_ISREG(st.st_mode)) {
/* Write to the swap file to guarantee space for MM. */
unsigned long n;
if (size == 0) {
fprintf(stderr, "mkswap: No size specified for %s\n", file);
usage();
}
memset(block, 0, sizeof(block));
for (n= 0; n < size; n += r) {
r= size > sizeof(block) ? sizeof(block) : size;
if ((r= write(fd, block, r)) <= 0) {
fprintf(stderr, "mkswap: %s: %s\n",
file, r == 0 ? "End of file" : strerror(errno));
exit(1);
}
}
first= 1;
} else {
fprintf(stderr, "mkswap: %s is not a device or a file\n", file);
exit(1);
}
if (offset < SWAP_OFFSET) {
offset += SWAP_OFFSET;
if (size < SWAP_OFFSET) size= 0; else size -= SWAP_OFFSET;
}
swap_hdr.sh_magic[0]= SWAP_MAGIC0;
swap_hdr.sh_magic[1]= SWAP_MAGIC1;
swap_hdr.sh_magic[2]= SWAP_MAGIC2;
swap_hdr.sh_magic[3]= SWAP_MAGIC3;
swap_hdr.sh_version= SH_VERSION;
swap_hdr.sh_priority= 0;
swap_hdr.sh_offset= offset;
swap_hdr.sh_swapsize= size;
r= -1;
if (lseek(fd, SWAP_BOOTOFF, SEEK_SET) == -1
|| (r= read(fd, block, sizeof(block))) < sizeof(block)
) {
fprintf(stderr, "mkswap: %s: %s\n", file,
file, r >= 0 ? "End of file" : strerror(errno));
exit(1);
}
r= (first ? SWAP_BOOTOFF : OPTSWAP_BOOTOFF) - SWAP_BOOTOFF;
memcpy(block + r, &swap_hdr, sizeof(swap_hdr));
r= -1;
if (lseek(fd, SWAP_BOOTOFF, SEEK_SET) == -1
|| (r= write(fd, block, sizeof(block))) < sizeof(block)
) {
fprintf(stderr, "mkswap: %s: %s\n", file,
file, r >= 0 ? "End of file" : strerror(errno));
exit(1);
}
printf("%s: swapspace at offset %lu, size %lu kilobytes\n",
file, offset / 1024, size / 1024);
return 0;
}