Message ID | cover.1599470071.git.tgolembi@redhat.com |
---|---|
Headers | show |
Series | qga: add command guest-get-disk | expand |
gentle reminder On Mon, Sep 07, 2020 at 11:14:39AM +0200, Tomáš Golembiovský wrote: > Adds command to list disks of the VM. > > The patch does compile on master but to work properly it requires changes to > qemu-ga by Thomas Huth in series: Allow guest-get-fsinfo also for non-PCI > devices. > > v2: > - added new struct in API to handle the information > - split changes into several patches > - for Linux list also slaves, partitions and virtual disks so that the disk > hierarchy is preserved > - fixed issues pointed out by Michael > > Tomáš Golembiovský (3): > qga: add command guest-get-disks > qga: add implementation of guest-get-disks for Linux > qga: add implementation of guest-get-disks for Windows > > qga/commands-posix.c | 241 ++++++++++++++++++++++++++++++++++++++++++- > qga/commands-win32.c | 91 ++++++++++++++++ > qga/qapi-schema.json | 29 ++++++ > 3 files changed, 360 insertions(+), 1 deletion(-) > > -- > 2.25.0 >
On Mon, Sep 07, 2020 at 11:14:41AM +0200, Tomáš Golembiovský wrote: > The command lists all disks (real and virtual) as well as disk > partitions. For each disk the list of slave disks is also listed and > /dev path is used as a handle so it can be matched with "name" filed of > other returned disk entries. For disk partitions the "slave" list is > populated with the the parent device for easier tracking of hierarchy. > > Example output: > { > "return": [ > ... > { > "name": "/dev/dm-0", > "partition": false, > "slaves": [ > "/dev/sda2" > ], > "alias": "luks-7062202e-5b9b-433e-81e8-6628c40da9f7" > }, > { > "name": "/dev/sda2", > "partition": true, > "slaves": [ > "/dev/sda" > ] > }, > { > "name": "/dev/sda", > "partition": false, > "address": { > "serial": "SAMSUNG_MZ7LN512HCHP-000L1_S1ZKNXAG822493", > "bus-type": "sata", > ... > "dev": "/dev/sda", > "target": 0 > }, > "slaves": [] > }, > ... > ] > } > > Signed-off-by: Tomáš Golembiovský <tgolembi@redhat.com> > --- > qga/commands-posix.c | 247 +++++++++++++++++++++++++++++++++++++++++-- > 1 file changed, 240 insertions(+), 7 deletions(-) > > diff --git a/qga/commands-posix.c b/qga/commands-posix.c > index f99731af51..3babc25c09 100644 > --- a/qga/commands-posix.c > +++ b/qga/commands-posix.c > @@ -62,6 +62,9 @@ extern char **environ; > #endif > #endif > > +G_DEFINE_AUTOPTR_CLEANUP_FUNC(GuestFilesystemInfo, > + qapi_free_GuestFilesystemInfo) > + > static void ga_wait_child(pid_t pid, int *status, Error **errp) > { > pid_t rpid; > @@ -1150,6 +1153,21 @@ 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; > + } > + if (strstr(syspath, "/devices/virtual/block/")) { > + return true; > + } else { > + return false; > + } > +} > + > /* Dispatch to functions for virtual/real device */ > static void build_guest_fsinfo_for_device(char const *devpath, > GuestFilesystemInfo *fs, > @@ -1168,6 +1186,7 @@ static void build_guest_fsinfo_for_device(char const *devpath, > > g_debug(" parse sysfs path '%s'", syspath); > > + /* TODO: use is_disk_virtual() */ > if (strstr(syspath, "/devices/virtual/block/")) { > build_guest_fsinfo_for_virtual_device(syspath, fs, errp); > } else { > @@ -1177,6 +1196,225 @@ 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(); > + udevice = udev_device_new_from_syspath(udev, syspath); > + if (udev == NULL || udevice == NULL) { > + g_debug("failed to query udev"); > + } else { > + const char *alias = udev_device_get_property_value( > + udevice, "DM_NAME"); > + if (alias != NULL && *alias != 0) { > + ret = g_strdup(alias); > + } > + } > + > + 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(); > + udevice = udev_device_new_from_syspath(udev, syspath); > + if (udev == NULL || udevice == NULL) { > + g_debug("failed to query udev"); > + } else { > + ret = g_strdup(udev_device_get_devnode(udevice)); > + } > + udev_unref(udev); > + udev_device_unref(udevice); > + return ret; > +} > + > +GuestDiskInfoList *qmp_guest_get_disks(Error **errp) > +{ > + GuestDiskInfoList *item, *ret = NULL; > + GuestDiskInfo *disk, *partition; > + 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_dir = NULL, *slaves_dir = NULL; > + struct dirent *de_disk, *de_slaves; > + DIR *dp_disk = NULL, *dp_slaves = NULL; > + FILE *fp = NULL; > + size_t n = 0; > + 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_dir = g_strdup_printf("/sys/block/%s/size", de->d_name); > + fp = fopen(size_dir, "r"); > + if (!fp) { > + g_debug(" failed to read disk size"); > + continue; > + } > + if (getline(&line, &n, fp) == -1) { > + g_debug(" failed to read disk size"); > + fclose(fp); > + continue; > + } > + fclose(fp); These 10 lines can be reduced to just g_file_get_contents(size_dir, &line, NULL, NULL) > + if (strcmp(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); > + disk = g_new0(GuestDiskInfo, 1); > + disk->name = get_device_for_syspath(disk_dir); > + disk->partition = false; > + disk->alias = get_alias_for_syspath(disk_dir); > + if (disk->alias != NULL) { > + disk->has_alias = true; > + } > + 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; > + } > + } > + > + /* List slave disks */ > + slaves_dir = g_strdup_printf("%s/slaves", disk_dir); > + g_debug(" listing entries in: %s", slaves_dir); > + dp_slaves = opendir(slaves_dir); > + while ((de_slaves = readdir(dp_slaves)) != NULL) { > + g_autofree char *slave_dir = NULL; > + char *slave_dev; > + strList *slave_item = NULL; > + > + if ((strcmp(".", de_slaves->d_name) == 0) || > + (strcmp("..", de_slaves->d_name) == 0)) { > + continue; > + } > + > + /* Add slave disks */ > + slave_dir = g_strdup_printf("%s/%s", > + slaves_dir, de_slaves->d_name); > + slave_dev = get_device_for_syspath(slave_dir); > + if (slave_dev != NULL) { > + g_debug(" adding slave device: %s", slave_dev); > + slave_item = g_new0(strList, 1); > + slave_item->value = slave_dev; > + slave_item->next = disk->slaves; > + disk->slaves = slave_item; > + } > + } > + closedir(dp_slaves); Since you are only using d_name, you can use g_dir_open and g_dir_read_name and g_dir_close. This always skips . and .. for you. > + > + /* > + * Detect partitions subdirectory name is "<parent><number>" or > + * "<parent>p<number>" > + */ > + dp_disk = opendir(disk_dir); > + while ((de_disk = readdir(dp_disk)) != NULL) { > + size_t len; > + g_autofree char *partition_dir = NULL; > + > + if (!(de_disk->d_type & DT_DIR)) { > + continue; > + } > + > + len = strlen(de->d_name); > + if (!(strncmp(de->d_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); > + partition = g_new0(GuestDiskInfo, 1); > + partition->name = get_device_for_syspath(partition_dir); > + partition->partition = true; > + /* Add parent disk as slave for easier tracking of hierarchy */ > + partition->slaves = g_new0(strList, 1); > + partition->slaves->value = g_strdup(disk->name); > + > + item = g_new0(GuestDiskInfoList, 1); > + item->value = partition; > + item->next = ret; > + ret = item; > + > + } > + closedir(dp_disk); > + } > + 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 +3047,8 @@ 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) { > @@ -3042,9 +3281,3 @@ GuestOSInfo *qmp_guest_get_osinfo(Error **errp) > > return info; > } > - > -GuestDiskInfoList *qmp_guest_get_disks(Error **errp) > -{ > - error_setg(errp, QERR_UNSUPPORTED); > - return NULL; > -} > -- > 2.25.0 > > Regards, Daniel