1 files changed, 94 insertions, 0 deletions
diff --git a/toolbox/mkswap.c b/toolbox/mkswap.c
new file mode 100644
index 000000000..1710ef6f8
--- /dev/null
+++ b/toolbox/mkswap.c
@@ -0,0 +1,94 @@
+#include <stdio.h>
+#include <unistd.h>
+#include <asm/page.h>
+#include <sys/swap.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+
+/* XXX This needs to be obtained from kernel headers. See b/9336527 */
+struct linux_swap_header {
+    char            bootbits[1024]; /* Space for disklabel etc. */
+    uint32_t        version;
+    uint32_t        last_page;
+    uint32_t        nr_badpages;
+    unsigned char   sws_uuid[16];
+    unsigned char   sws_volume[16];
+    uint32_t        padding[117];
+    uint32_t        badpages[1];
+};
+
+#define MAGIC_SWAP_HEADER     "SWAPSPACE2"
+#define MAGIC_SWAP_HEADER_LEN 10
+#define MIN_PAGES             10
+
+int mkswap_main(int argc, char **argv)
+{
+    int err = 0;
+    int fd;
+    ssize_t len;
+    off_t swap_size;
+    int pagesize;
+    struct linux_swap_header sw_hdr;
+
+    if (argc != 2) {
+        fprintf(stderr, "Usage: %s <filename>\n", argv[0]);
+        return -EINVAL;
+    }
+
+    fd = open(argv[1], O_WRONLY);
+    if (fd < 0) {
+        err = errno;
+        fprintf(stderr, "Cannot open %s\n", argv[1]);
+        return err;
+    }
+
+    pagesize = getpagesize();
+    /* Determine the length of the swap file */
+    swap_size = lseek(fd, 0, SEEK_END);
+    if (swap_size < MIN_PAGES * pagesize) {
+        fprintf(stderr, "Swap file needs to be at least %dkB\n",
+            (MIN_PAGES * pagesize) >> 10);
+        err = -ENOSPC;
+        goto err;
+    }
+    if (lseek(fd, 0, SEEK_SET)) {
+        err = errno;
+        fprintf(stderr, "Can't seek to the beginning of the file\n");
+        goto err;
+    }
+
+    memset(&sw_hdr, 0, sizeof(sw_hdr));
+    sw_hdr.version = 1;
+    sw_hdr.last_page = (swap_size / pagesize) - 1;
+
+    len = write(fd, &sw_hdr, sizeof(sw_hdr));
+    if (len != sizeof(sw_hdr)) {
+        err = errno;
+        fprintf(stderr, "Failed to write swap header into %s\n", argv[1]);
+        goto err;
+    }
+
+    /* Write the magic header */
+    if (lseek(fd, pagesize - MAGIC_SWAP_HEADER_LEN, SEEK_SET) < 0) {
+        err = errno;
+        fprintf(stderr, "Failed to seek into %s\n", argv[1]);
+        goto err;
+    }
+
+    len = write(fd, MAGIC_SWAP_HEADER, MAGIC_SWAP_HEADER_LEN);
+    if (len != MAGIC_SWAP_HEADER_LEN) {
+        err = errno;
+        fprintf(stderr, "Failed to write magic swap header into %s\n", argv[1]);
+        goto err;
+    }
+
+    if (fsync(fd) < 0) {
+        err = errno;
+        fprintf(stderr, "Failed to sync %s\n", argv[1]);
+        goto err;
+    }
+err:
+    close(fd);
+    return err;
+}