367297c3d7
Add swap utilities (mkswap, swapon, swapoff) to the toolbox Change-Id: If5ed6981670a1cdda6b528b587dbc1be7ccdf832 Signed-off-by: Rom Lemarchand <romlem@google.com>
94 lines
2.4 KiB
C
94 lines
2.4 KiB
C
#include <stdio.h>
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#include <unistd.h>
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#include <asm/page.h>
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#include <sys/swap.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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/* XXX This needs to be obtained from kernel headers. See b/9336527 */
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struct linux_swap_header {
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char bootbits[1024]; /* Space for disklabel etc. */
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uint32_t version;
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uint32_t last_page;
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uint32_t nr_badpages;
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unsigned char sws_uuid[16];
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unsigned char sws_volume[16];
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uint32_t padding[117];
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uint32_t badpages[1];
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};
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#define MAGIC_SWAP_HEADER "SWAPSPACE2"
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#define MAGIC_SWAP_HEADER_LEN 10
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#define MIN_PAGES 10
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int mkswap_main(int argc, char **argv)
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{
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int err = 0;
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int fd;
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ssize_t len;
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off_t swap_size;
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int pagesize;
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struct linux_swap_header sw_hdr;
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if (argc != 2) {
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fprintf(stderr, "Usage: %s <filename>\n", argv[0]);
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return -EINVAL;
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}
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fd = open(argv[1], O_WRONLY);
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if (fd < 0) {
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err = errno;
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fprintf(stderr, "Cannot open %s\n", argv[1]);
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return err;
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}
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pagesize = getpagesize();
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/* Determine the length of the swap file */
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swap_size = lseek(fd, 0, SEEK_END);
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if (swap_size < MIN_PAGES * pagesize) {
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fprintf(stderr, "Swap file needs to be at least %dkB\n",
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(MIN_PAGES * pagesize) >> 10);
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err = -ENOSPC;
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goto err;
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}
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if (lseek(fd, 0, SEEK_SET)) {
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err = errno;
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fprintf(stderr, "Can't seek to the beginning of the file\n");
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goto err;
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}
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memset(&sw_hdr, 0, sizeof(sw_hdr));
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sw_hdr.version = 1;
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sw_hdr.last_page = (swap_size / pagesize) - 1;
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len = write(fd, &sw_hdr, sizeof(sw_hdr));
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if (len != sizeof(sw_hdr)) {
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err = errno;
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fprintf(stderr, "Failed to write swap header into %s\n", argv[1]);
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goto err;
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}
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/* Write the magic header */
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if (lseek(fd, pagesize - MAGIC_SWAP_HEADER_LEN, SEEK_SET) < 0) {
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err = errno;
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fprintf(stderr, "Failed to seek into %s\n", argv[1]);
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goto err;
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}
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len = write(fd, MAGIC_SWAP_HEADER, MAGIC_SWAP_HEADER_LEN);
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if (len != MAGIC_SWAP_HEADER_LEN) {
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err = errno;
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fprintf(stderr, "Failed to write magic swap header into %s\n", argv[1]);
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goto err;
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}
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if (fsync(fd) < 0) {
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err = errno;
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fprintf(stderr, "Failed to sync %s\n", argv[1]);
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goto err;
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}
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err:
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close(fd);
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return err;
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}
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