On Wed, Oct 7, 2020 at 11:46 AM Tomáš Golembiovský <[email protected]>
wrote:
> The command lists all disks (real and virtual) as well as disk
> partitions. For each disk the list of dependent disks is also listed and
> /dev path is used as a handle so it can be matched with "name" field of
> other returned disk entries. For disk partitions the "dependents" list
> is populated with the the parent device for easier tracking of
> hierarchy.
>
> Example output:
> {
> "return": [
> ...
> {
> "name": "/dev/dm-0",
> "partition": false,
> "dependents": [
> "/dev/sda2"
> ],
> "alias": "luks-7062202e-5b9b-433e-81e8-6628c40da9f7"
> },
> {
> "name": "/dev/sda2",
> "partition": true,
> "dependents": [
> "/dev/sda"
> ]
> },
> {
> "name": "/dev/sda",
> "partition": false,
> "address": {
> "serial": "SAMSUNG_MZ7LN512HCHP-000L1_S1ZKNXAG822493",
> "bus-type": "sata",
> ...
> "dev": "/dev/sda",
> "target": 0
> },
> "dependents": []
> },
> ...
> ]
> }
>
> Signed-off-by: Tomáš Golembiovský <[email protected]>
> ---
> qga/commands-posix.c | 293 +++++++++++++++++++++++++++++++++++++++++--
> 1 file changed, 284 insertions(+), 9 deletions(-)
>
> diff --git a/qga/commands-posix.c b/qga/commands-posix.c
> index 422144bcff..b0ec1223c9 100644
> --- a/qga/commands-posix.c
> +++ b/qga/commands-posix.c
> @@ -1150,12 +1150,25 @@ static void
> build_guest_fsinfo_for_virtual_device(char const *syspath,
> closedir(dir);
> }
>
> +static bool is_disk_virtual(const char *devpath, Error **errp)
> +{
> + g_autofree char *syspath = realpath(devpath, NULL);
> +
> + if (!syspath) {
> + error_setg_errno(errp, errno, "realpath(\"%s\")", devpath);
> + return false;
> + }
> + return strstr(syspath, "/devices/virtual/block/") != NULL;
> +}
> +
> /* Dispatch to functions for virtual/real device */
> static void build_guest_fsinfo_for_device(char const *devpath,
> GuestFilesystemInfo *fs,
> Error **errp)
> {
> + ERRP_GUARD();
> char *syspath = realpath(devpath, NULL);
> + bool is_virtual = false;
>
> if (!syspath) {
> error_setg_errno(errp, errno, "realpath(\"%s\")", devpath);
> @@ -1167,8 +1180,11 @@ static void build_guest_fsinfo_for_device(char
> const *devpath,
> }
>
> g_debug(" parse sysfs path '%s'", syspath);
> -
> - if (strstr(syspath, "/devices/virtual/block/")) {
> + is_virtual = is_disk_virtual(syspath, errp);
> + if (*errp != NULL) {
>
I think it's leaking syspath.
+ return;
> + }
> + if (is_virtual) {
> build_guest_fsinfo_for_virtual_device(syspath, fs, errp);
> } else {
> build_guest_fsinfo_for_real_device(syspath, fs, errp);
> @@ -1177,6 +1193,270 @@ static void build_guest_fsinfo_for_device(char
> const *devpath,
> free(syspath);
> }
>
> +#ifdef CONFIG_LIBUDEV
> +
> +/*
> + * Wrapper around build_guest_fsinfo_for_device() for getting just
> + * the disk address.
> + */
> +static GuestDiskAddress *get_disk_address(const char *syspath, Error
> **errp)
> +{
> + g_autoptr(GuestFilesystemInfo) fs = NULL;
> +
> + fs = g_new0(GuestFilesystemInfo, 1);
> + build_guest_fsinfo_for_device(syspath, fs, errp);
> + if (fs->disk != NULL) {
> + return g_steal_pointer(&fs->disk->value);
> + }
> + return NULL;
> +}
> +
> +static char *get_alias_for_syspath(const char *syspath)
> +{
> + struct udev *udev = NULL;
> + struct udev_device *udevice = NULL;
> + char *ret = NULL;
> +
> + udev = udev_new();
> + if (udev == NULL) {
> + g_debug("failed to query udev");
> + goto out;
> + }
> + udevice = udev_device_new_from_syspath(udev, syspath);
> + if (udevice == NULL) {
> + g_debug("failed to query udev for path: %s", syspath);
> + goto out;
> + } else {
> + const char *alias = udev_device_get_property_value(
> + udevice, "DM_NAME");
> + /*
> + * NULL means there was an error and empty string means there is
> no
> + * alias. In case of no alias we return NULL instead of empty
> string.
> + */
> + if (alias == NULL) {
> + g_debug("failed to query udev for device alias for: %s",
> + syspath);
> + } else if (*alias != 0) {
> + ret = g_strdup(alias);
> + }
> + }
> +
> +out:
> + udev_unref(udev);
> + udev_device_unref(udevice);
> + return ret;
> +}
> +
> +static char *get_device_for_syspath(const char *syspath)
> +{
> + struct udev *udev = NULL;
> + struct udev_device *udevice = NULL;
> + char *ret = NULL;
> +
> + udev = udev_new();
> + if (udev == NULL) {
> + g_debug("failed to query udev");
> + goto out;
> + }
> + udevice = udev_device_new_from_syspath(udev, syspath);
> + if (udevice == NULL) {
> + g_debug("failed to query udev for path: %s", syspath);
> + goto out;
> + } else {
> + ret = g_strdup(udev_device_get_devnode(udevice));
> + }
> +
> +out:
> + udev_unref(udev);
> + udev_device_unref(udevice);
> + return ret;
> +}
> +
> +static void get_disk_deps(const char *disk_dir, GuestDiskInfo *disk)
> +{
> + g_autofree char *deps_dir = NULL;
> + const gchar *dep;
> + GDir *dp_deps = NULL;
> +
> + /* List dependent disks */
> + deps_dir = g_strdup_printf("%s/slaves", disk_dir);
> + g_debug(" listing entries in: %s", deps_dir);
> + dp_deps = g_dir_open(deps_dir, 0, NULL);
> + if (dp_deps == NULL) {
> + g_debug("failed to list entries in %s", deps_dir);
> + return;
> + }
> + while ((dep = g_dir_read_name(dp_deps)) != NULL) {
> + g_autofree char *dep_dir = NULL;
> + strList *dep_item = NULL;
> + char *dev_name;
> +
> + /* Add dependent disks */
> + dep_dir = g_strdup_printf("%s/%s", deps_dir, dep);
> + dev_name = get_device_for_syspath(dep_dir);
> + if (dev_name != NULL) {
> + g_debug(" adding dependent device: %s", dev_name);
> + dep_item = g_new0(strList, 1);
> + dep_item->value = dev_name;
> + dep_item->next = disk->dependents;
> + disk->dependents = dep_item;
> + }
> + }
> + g_dir_close(dp_deps);
> +}
> +
> +/*
> + * Detect partitions subdirectory, name is "<disk_name><number>" or
> + * "<disk_name>p<number>"
> + *
> + * @disk_name -- last component of /sys path (e.g. sda)
> + * @disk_dir -- sys path of the disk (e.g. /sys/block/sda)
> + * @disk_dev -- device node of the disk (e.g. /dev/sda)
> + */
> +static GuestDiskInfoList *get_disk_partitions(
> + GuestDiskInfoList *list,
> + const char *disk_name, const char *disk_dir,
> + const char *disk_dev)
> +{
> + GuestDiskInfoList *item, *ret = list;
> + struct dirent *de_disk;
> + DIR *dp_disk = NULL;
> + size_t len = strlen(disk_name);
> +
> + dp_disk = opendir(disk_dir);
> + while ((de_disk = readdir(dp_disk)) != NULL) {
> + g_autofree char *partition_dir = NULL;
> + char *dev_name;
> + GuestDiskInfo *partition;
> +
> + if (!(de_disk->d_type & DT_DIR)) {
> + continue;
> + }
> +
> + if (!(strncmp(disk_name, de_disk->d_name, len) == 0 &&
> + ((*(de_disk->d_name + len) == 'p' &&
> + isdigit(*(de_disk->d_name + len + 1))) ||
> + isdigit(*(de_disk->d_name + len))))) {
> + continue;
> + }
> +
> + partition_dir = g_strdup_printf("%s/%s",
> + disk_dir, de_disk->d_name);
> + dev_name = get_device_for_syspath(partition_dir);
> + if (dev_name == NULL) {
> + g_debug("Failed to get device name for syspath: %s",
> + disk_dir);
> + continue;
> + }
> + partition = g_new0(GuestDiskInfo, 1);
> + partition->name = dev_name;
> + partition->partition = true;
> + /* Add parent disk as dependent for easier tracking of hierarchy
> */
> + partition->dependents = g_new0(strList, 1);
> + partition->dependents->value = g_strdup(disk_dev);
> +
> + item = g_new0(GuestDiskInfoList, 1);
> + item->value = partition;
> + item->next = ret;
> + ret = item;
> +
> + }
> + closedir(dp_disk);
> +
> + return ret;
> +}
> +
> +GuestDiskInfoList *qmp_guest_get_disks(Error **errp)
> +{
> + GuestDiskInfoList *item, *ret = NULL;
> + GuestDiskInfo *disk;
> + DIR *dp = NULL;
> + struct dirent *de = NULL;
> +
> + g_debug("listing /sys/block directory");
> + dp = opendir("/sys/block");
> + if (dp == NULL) {
> + error_setg_errno(errp, errno, "Can't open directory
> \"/sys/block\"");
> + return NULL;
> + }
> + while ((de = readdir(dp)) != NULL) {
> + g_autofree char *disk_dir = NULL, *line = NULL,
> + *size_path = NULL, *deps_dir = NULL;
> + char *dev_name;
> + Error *local_err = NULL;
> + if (de->d_type != DT_LNK) {
> + g_debug(" skipping entry: %s", de->d_name);
> + continue;
> + }
> +
> + /* Check size and skip zero-sized disks */
> + g_debug(" checking disk size");
> + size_path = g_strdup_printf("/sys/block/%s/size", de->d_name);
> + if (!g_file_get_contents(size_path, &line, NULL, NULL)) {
> + g_debug(" failed to read disk size");
> + continue;
> + }
> + if (g_strcmp0(line, "0\n") == 0) {
> + g_debug(" skipping zero-sized disk");
> + continue;
> + }
> +
> + g_debug(" adding %s", de->d_name);
> + disk_dir = g_strdup_printf("/sys/block/%s", de->d_name);
> + dev_name = get_device_for_syspath(disk_dir);
> + if (dev_name == NULL) {
> + g_debug("Failed to get device name for syspath: %s",
> + disk_dir);
> + continue;
> + }
> + disk = g_new0(GuestDiskInfo, 1);
> + disk->name = dev_name;
> + disk->partition = false;
> + disk->alias = get_alias_for_syspath(disk_dir);
> + disk->has_alias = (disk->alias != NULL);
> + item = g_new0(GuestDiskInfoList, 1);
> + item->value = disk;
> + item->next = ret;
> + ret = item;
> +
> + /* Get address for non-virtual devices */
> + bool is_virtual = is_disk_virtual(disk_dir, &local_err);
> + if (local_err != NULL) {
> + g_debug(" failed to check disk path, ignoring error: %s",
> + error_get_pretty(local_err));
> + error_free(local_err);
> + local_err = NULL;
> + /* Don't try to get the address */
> + is_virtual = true;
> + }
> + if (!is_virtual) {
> + disk->address = get_disk_address(disk_dir, &local_err);
> + if (local_err != NULL) {
> + g_debug(" failed to get device info, ignoring error: %s",
> + error_get_pretty(local_err));
> + error_free(local_err);
> + local_err = NULL;
> + } else if (disk->address != NULL) {
> + disk->has_address = true;
> + }
> + }
> +
> + get_disk_deps(disk_dir, disk);
> + ret = get_disk_partitions(ret, de->d_name, disk_dir, dev_name);
> + }
> + return ret;
> +}
> +
> +#else
> +
> +GuestDiskInfoList *qmp_guest_get_disks(Error **errp)
> +{
> + error_setg(errp, QERR_UNSUPPORTED);
> + return NULL;
> +}
> +
> +#endif
> +
> /* Return a list of the disk device(s)' info which @mount lies on */
> static GuestFilesystemInfo *build_guest_fsinfo(struct FsMount *mount,
> Error **errp)
> @@ -2809,7 +3089,8 @@ GList *ga_command_blacklist_init(GList *blacklist)
> const char *list[] = {
> "guest-get-fsinfo", "guest-fsfreeze-status",
> "guest-fsfreeze-freeze", "guest-fsfreeze-freeze-list",
> - "guest-fsfreeze-thaw", "guest-get-fsinfo", NULL};
> + "guest-fsfreeze-thaw", "guest-get-fsinfo",
> + "guest-get-disks", NULL};
> char **p = (char **)list;
>
> while (*p) {
> @@ -3051,9 +3332,3 @@ GuestDeviceInfoList *qmp_guest_get_devices(Error
> **errp)
>
> return NULL;
> }
> -
> -GuestDiskInfoList *qmp_guest_get_disks(Error **errp)
> -{
> - error_setg(errp, QERR_UNSUPPORTED);
> - return NULL;
> -}
> --
> 2.28.0
>
>
lgtm otherwise
--
Marc-André Lureau
