added user mode Linux Copy On Write disk image support - added -snapshot support (initial patch by Rusty Russell)

git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@309 c046a42c-6fe2-441c-8c8c-71466251a162

1 files changed, 142 insertions, 0 deletions

diff --git a/vlmkcow.c b/vlmkcow.c
new file mode 100644
index 0000000000..435ed21d2d
--- /dev/null
+++ b/vlmkcow.c
@@ -0,0 +1,142 @@
+/*
+ * create a COW disk image
+ * 
+ * Copyright (c) 2003 Fabrice Bellard
+ * 
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+#include <stdlib.h>
+#include <stdio.h>
+#include <stdarg.h>
+#include <string.h>
+#include <getopt.h>
+#include <inttypes.h>
+#include <unistd.h>
+#include <sys/mman.h>
+#include <fcntl.h>
+#include <signal.h>
+#include <time.h>
+#include <sys/time.h>
+#include <malloc.h>
+#include <termios.h>
+#include <sys/poll.h>
+#include <errno.h>
+#include <sys/wait.h>
+#include <netinet/in.h>
+
+#include "vl.h"
+
+#define NO_THUNK_TYPE_SIZE
+#include "thunk.h"
+
+int cow_create(int cow_fd, const char *image_filename, 
+               int64_t image_sectors)
+{
+    struct cow_header_v2 cow_header;
+    int fd;
+    struct stat st;
+
+    memset(&cow_header, 0, sizeof(cow_header));
+    cow_header.magic = htonl(COW_MAGIC);
+    cow_header.version = htonl(COW_VERSION);
+    if (image_filename) {
+        fd = open(image_filename, O_RDONLY);
+        if (fd < 0) {
+            perror(image_filename);
+            exit(1);
+        }
+        image_sectors = lseek64(fd, 0, SEEK_END);
+        if (fstat(fd, &st) != 0) {
+            close(fd);
+            return -1;
+        }
+        close(fd);
+        image_sectors /= 512;
+        cow_header.mtime = htonl(st.st_mtime);
+        realpath(image_filename, cow_header.backing_file);
+    }
+    cow_header.sectorsize = htonl(512);
+    cow_header.size = image_sectors * 512;
+#ifndef WORDS_BIGENDIAN
+    cow_header.size = bswap64(cow_header.size);
+#endif    
+    write(cow_fd, &cow_header, sizeof(cow_header));
+    /* resize to include at least all the bitmap */
+    ftruncate(cow_fd, sizeof(cow_header) + ((image_sectors + 7) >> 3));
+    lseek(cow_fd, 0, SEEK_SET);
+    return 0;
+}
+
+void help(void)
+{
+    printf("usage vlmkcow [-h] [-f disk_image] cow_image [cow_size]\n"
+           "Create a Copy On Write disk image from an optional raw disk image\n"
+           "\n"
+           "-f disk_image   set the raw disk image name\n"
+           "cow_image       the created cow_image\n"
+           "cow_size        the create cow_image size in MB if no raw disk image is used\n"
+           "\n"
+           "Once the cow_image is created from a raw disk image, you must not modify the original raw disk image\n"
+           );
+    exit(1);
+}
+
+int main(int argc, char **argv)
+{
+    const char *image_filename, *cow_filename;
+    int cow_fd, c, nb_args;
+    int64_t image_size;
+    
+    image_filename = NULL;
+    image_size = 0;
+    for(;;) {
+        c = getopt(argc, argv, "hf:");
+        if (c == -1)
+            break;
+        switch(c) {
+        case 'h':
+            help();
+            break;
+        case 'f':
+            image_filename = optarg;
+            break;
+        }
+    }
+    if (!image_filename)
+        nb_args = 2;
+    else
+        nb_args = 1;
+    if (optind + nb_args != argc)
+        help();
+
+    cow_filename = argv[optind];
+    if (nb_args == 2) {
+        image_size = (int64_t)atoi(argv[optind + 1]) * 2 * 1024;
+    }
+
+    cow_fd = open(cow_filename, O_RDWR | O_CREAT | O_TRUNC, 0644);
+    if (!cow_fd < 0)
+        return -1;
+    if (cow_create(cow_fd, image_filename, image_size) < 0) {
+        fprintf(stderr, "%s: error while formating\n", cow_filename);
+        exit(1);
+    }
+    close(cow_fd);
+    return 0;
+}