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-rw-r--r--examples/create_disk.c122
1 files changed, 122 insertions, 0 deletions
diff --git a/examples/create_disk.c b/examples/create_disk.c
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+++ b/examples/create_disk.c
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+/* Example showing how to create a disk image. */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <guestfs.h>
+
+int
+main (int argc, char *argv[])
+{
+ guestfs_h *g;
+ size_t i;
+
+ g = guestfs_create ();
+ if (g == NULL) {
+ perror ("failed to create libguestfs handle");
+ exit (EXIT_FAILURE);
+ }
+
+ /* Create a raw-format sparse disk image, 512 MB in size. */
+ int fd = open ("disk.img", O_CREAT|O_WRONLY|O_TRUNC|O_NOCTTY, 0666);
+ if (fd == -1) {
+ perror ("disk.img");
+ exit (EXIT_FAILURE);
+ }
+ if (ftruncate (fd, 512 * 1024 * 1024) == -1) {
+ perror ("disk.img: truncate");
+ exit (EXIT_FAILURE);
+ }
+ if (close (fd) == -1) {
+ perror ("disk.img: close");
+ exit (EXIT_FAILURE);
+ }
+
+ /* Set the trace flag so that we can see each libguestfs call. */
+ guestfs_set_trace (g, 1);
+
+ /* Set the autosync flag so that the disk will be synchronized
+ * automatically when the libguestfs handle is closed.
+ */
+ guestfs_set_autosync (g, 1);
+
+ /* Add the disk image to libguestfs. */
+ if (guestfs_add_drive_opts (g, "disk.img",
+ GUESTFS_ADD_DRIVE_OPTS_FORMAT, "raw", /* raw format */
+ GUESTFS_ADD_DRIVE_OPTS_READONLY, 0, /* for write */
+ -1) /* this marks end of optional arguments */
+ == -1)
+ exit (EXIT_FAILURE);
+
+ /* Run the libguestfs back-end. */
+ if (guestfs_launch (g) == -1)
+ exit (EXIT_FAILURE);
+
+ /* Get the list of devices. Because we only added one drive
+ * above, we expect that this list should contain a single
+ * element.
+ */
+ char **devices = guestfs_list_devices (g);
+ if (devices == NULL)
+ exit (EXIT_FAILURE);
+ if (devices[0] == NULL || devices[1] != NULL) {
+ fprintf (stderr, "error: expected a single device from list-devices\n");
+ exit (EXIT_FAILURE);
+ }
+
+ /* Partition the disk as one single MBR partition. */
+ if (guestfs_part_disk (g, devices[0], "mbr") == -1)
+ exit (EXIT_FAILURE);
+
+ /* Get the list of partitions. We expect a single element, which
+ * is the partition we have just created.
+ */
+ char **partitions = guestfs_list_partitions (g);
+ if (partitions == NULL)
+ exit (EXIT_FAILURE);
+ if (partitions[0] == NULL || partitions[1] != NULL) {
+ fprintf (stderr, "error: expected a single partition from list-partitions\n");
+ exit (EXIT_FAILURE);
+ }
+
+ /* Create a filesystem on the partition. */
+ if (guestfs_mkfs (g, "ext4", partitions[0]) == -1)
+ exit (EXIT_FAILURE);
+
+ /* Now mount the filesystem so that we can add files. */
+ if (guestfs_mount_options (g, "", partitions[0], "/") == -1)
+ exit (EXIT_FAILURE);
+
+ /* Create some files and directories. */
+ if (guestfs_touch (g, "/empty") == -1)
+ exit (EXIT_FAILURE);
+ const char *message = "Hello, world\n";
+ if (guestfs_write (g, "/hello", message, strlen (message)) == -1)
+ exit (EXIT_FAILURE);
+ if (guestfs_mkdir (g, "/foo") == -1)
+ exit (EXIT_FAILURE);
+
+ /* This one uploads the local file /etc/resolv.conf into
+ * the disk image.
+ */
+ if (guestfs_upload (g, "/etc/resolv.conf", "/foo/resolv.conf") == -1)
+ exit (EXIT_FAILURE);
+
+ /* Because 'autosync' was set (above) we can just close the handle
+ * and the disk contents will be synchronized. You can also do
+ * this manually by calling guestfs_umount_all and guestfs_sync.
+ */
+ guestfs_close (g);
+
+ /* Free up the lists. */
+ for (i = 0; devices[i] != NULL; ++i)
+ free (devices[i]);
+ free (devices);
+ for (i = 0; partitions[i] != NULL; ++i)
+ free (partitions[i]);
+ free (partitions);
+
+ exit (EXIT_SUCCESS);
+}