The kvm run command should automatically pickup the image file to boot if one is
not explicitly specified.
Changes since V1:
- Deallocate variable 'line' when fopen(/proc/mounts) fails
Changes since V2:
- Instead of searching from /proc/mounts, use the device file /dev/root to
detect the device file for root file system
- Added a helper function get_host_image() to return the image to be used to
boot the virtual machine.
Changes since V3:
- The link '/dev/root' might be missing on some of the systems. Switched back
to using /proc/mounts file.
- Some simple reformatting
Signed-off-by: Prasad Joshi <prasadjoshi124@xxxxxxxxx>
---
tools/kvm/kvm-run.c | 109 +++++++++++++++++++++++++++++++++++++++++++++-----
1 files changed, 98 insertions(+), 11 deletions(-)
diff --git a/tools/kvm/kvm-run.c b/tools/kvm/kvm-run.c
index 17fef20..c3da21f 100644
--- a/tools/kvm/kvm-run.c
+++ b/tools/kvm/kvm-run.c
@@ -9,6 +9,7 @@
#include <sys/utsname.h>
#include <sys/types.h>
#include <sys/stat.h>
+#include <ctype.h>
/* user defined header files */
#include <linux/types.h>
@@ -214,12 +215,91 @@ static const char *find_kernel(void)
return NULL;
}
+static int root_device(char *dev, long *part)
+{
+ FILE *fp;
+ char *line;
+ int tmp;
+ size_t nr_read;
+ char device[PATH_MAX];
+ char mnt_pt[PATH_MAX];
+ char resolved_path[PATH_MAX];
+ char *p;
+ struct stat st;
+
+ fp = fopen("/proc/mounts", "r");
+ if (!fp)
+ return -1;
+
+ line = NULL;
+ tmp = 0;
+ while (!feof(fp)) {
+ if (getline(&line, &nr_read, fp) < 0)
+ break;
+ sscanf(line, "%s %s", device, mnt_pt);
+ if (!strncmp(device, "/dev", 4) && !strcmp(mnt_pt, "/")) {
+ tmp = 1;
+ break;
+ }
+ }
+ fclose(fp);
+ free(line);
+
+ if (!tmp)
+ return -1;
+
+ /* get the absolute path */
+ if (!realpath(device, resolved_path))
+ return -1;
+
+ /* find the partition number */
+ p = resolved_path;
+ while (*p) {
+ if (isdigit(*p)) {
+ strncpy(dev, resolved_path, p - resolved_path);
+ *part = atol(p);
+ break;
+ }
+ p++;
+ }
+
+ /* verify the device path */
+ if (stat(dev, &st) < 0)
+ return -1;
+ return 0;
+}
+
+static char *host_image(char *cmd_line, size_t size)
+{
+ char *t;
+ char device[PATH_MAX];
+ long part = 0;
+
+ t = malloc(PATH_MAX);
+ if (!t)
+ return NULL;
+
+ /* check for the root file system */
+ if (root_device(device, &part) < 0) {
+ free(t);
+ return NULL;
+ }
+ strncpy(t, device, PATH_MAX);
+ if (!strstr(cmd_line, "root=")) {
+ char tmp[PATH_MAX];
+ snprintf(tmp, sizeof(tmp), "root=/dev/vda%ld rw ", part);
+ strlcat(cmd_line, tmp, size);
+ }
+ return t;
+}
+
int kvm_cmd_run(int argc, const char **argv, const char *prefix)
{
static char real_cmdline[2048];
int exit_code = 0;
int i;
struct virtio_net_parameters net_params;
+ char *hi;
signal(SIGALRM, handle_sigalrm);
signal(SIGQUIT, handle_sigquit);
@@ -288,22 +368,29 @@ int kvm_cmd_run(int argc, const char **argv, const char *prefix)
kvm = kvm__init(kvm_dev, ram_size);
+ memset(real_cmdline, 0, sizeof(real_cmdline));
+ strcpy(real_cmdline, "notsc nolapic noacpi pci=conf1 console=ttyS0 ");
+ if (kernel_cmdline)
+ strlcat(real_cmdline, kernel_cmdline, sizeof(real_cmdline));
+
+ hi = NULL;
+ if (!image_filename) {
+ hi = host_image(real_cmdline, sizeof(real_cmdline));
+ if (hi) {
+ image_filename = hi;
+ readonly_image = true;
+ }
+ }
+
+ if (!strstr(real_cmdline, "root="))
+ strlcat(real_cmdline, "root=/dev/vda rw ", sizeof(real_cmdline));
+
if (image_filename) {
kvm->disk_image = disk_image__open(image_filename, readonly_image);
if (!kvm->disk_image)
die("unable to load disk image %s", image_filename);
}
-
- strcpy(real_cmdline, "notsc nolapic noacpi pci=conf1 console=ttyS0 ");
- if (!kernel_cmdline || !strstr(kernel_cmdline, "root=")) {
- strlcat(real_cmdline, "root=/dev/vda rw ",
- sizeof(real_cmdline));
- }
-
- if (kernel_cmdline) {
- strlcat(real_cmdline, kernel_cmdline, sizeof(real_cmdline));
- real_cmdline[sizeof(real_cmdline)-1] = '\0';
- }
+ free(hi);
if (!kvm__load_kernel(kvm, kernel_filename, initrd_filename,
real_cmdline))
--
1.7.1
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