[Ocfs2-tools-devel] [PATCH] adding code to mounted.c to translate /dev/dm-[N] names to /dev/mapper/xxx names.

[Tristan]

Btw, you're required to handle errors gracefully I guess:-)

such as,

dir = opendir(dirname);

if (!dir) {
ret = errno;
com_err(programe, 0, "Can not open dir %s: %s\n", dirname, strerror(ret));
return -1;
}

Tristan

XiaoweiHu wrote:
> Signed-off-by: XiaoweiHu <xiaowei.hu at oracle.com>
> ---
>  mounted.ocfs2/mounted.c |   76 +++++++++++++++++++++++++++++++++++++++++++++-
>  1 files changed, 74 insertions(+), 2 deletions(-)
>
> diff --git a/mounted.ocfs2/mounted.c b/mounted.ocfs2/mounted.c
> index e4c5877..c691a3d 100644
> --- a/mounted.ocfs2/mounted.c
> +++ b/mounted.ocfs2/mounted.c
> @@ -33,6 +33,7 @@
>  #include <linux/fd.h>
>  #include <string.h>
>  #include <sys/stat.h>
> +#include <dirent.h>
>  
>  #include <uuid/uuid.h>
>  
> @@ -155,12 +156,70 @@ static void ocfs2_print_quick_detect(struct list_head *dev_list)
>  	}
>  }
>  
> +char *devname_strndup(const char *s, int length)
> +{
> +        char *ret;
> +
> +        if (!s)
> +                return NULL;
> +
> +        if (!length)
> +                length = strlen(s);
> +
> +        ret = malloc(length + 1);
> +        if (ret) {
> +                strncpy(ret, s, length);
> +                ret[length] = '\0';
> +        }
> +        return ret;
> +}
> +
> +char *devname_strdup(const char *s)
> +{
> +        return devname_strndup(s, 0);
> +}
> +
> +void scan_dir_for_dev(char *dirname, dev_t devno, char **devname)
> +{
> +        DIR     *dir;
> +        struct dirent *dp;
> +        char    path[1024];
> +        int     dirlen;
> +        struct stat st;
> +
> +        if ((dir = opendir(dirname)) == NULL)
> +                return;
> +        dirlen = strlen(dirname) + 2;
> +        while ((dp = readdir(dir)) != 0) {
> +                if (dirlen + strlen(dp->d_name) >= sizeof(path))
> +                        continue;
> +
> +                if (dp->d_name[0] == '.' &&
> +                    ((dp->d_name[1] == 0) ||
> +                     ((dp->d_name[1] == '.') && (dp->d_name[2] == 0))))
> +                        continue;
> +
> +                sprintf(path, "%s/%s", dirname, dp->d_name);
> +                if (stat(path, &st) < 0)
> +                        continue;
> +
> +                if (S_ISBLK(st.st_mode) && st.st_rdev == devno) {
> +			*devname = devname_strdup(path);
> +                        break;
> +                }
> +        }
> +        closedir(dir);
> +        return;
> +}
> +
>  static errcode_t ocfs2_partition_list (struct list_head *dev_list)
>  {
>  	errcode_t ret = 0;
>  	FILE *proc;
>  	char line[256];
>  	char name[256];
> +	char *devname = NULL;
> +	int major,minor;
>  	ocfs2_devices *dev;
>  
>  	proc = fopen ("/proc/partitions", "r");
> @@ -170,14 +229,27 @@ static errcode_t ocfs2_partition_list (struct list_head *dev_list)
>  	}
>  
>  	while (fgets (line, sizeof(line), proc) != NULL) {
> -		if (sscanf(line, "%*d %*d %*d %99[^ \t\n]", name) != 1)
> +		if (sscanf(line, "%d %d %*d %99[^ \t\n]", &major, &minor, name) != 3)
>  			continue;
>  
>  		ret = ocfs2_malloc0(sizeof(ocfs2_devices), &dev);
>  		if (ret)
>  			goto bail;
>  
> -		snprintf(dev->dev_name, sizeof(dev->dev_name), "/dev/%s", name);
> +		/* Try to translate private device-mapper dm-<N> names
> +         	 * to standard /dev/mapper/<name>.
> +         	 */
> +        	if (!strncmp(name, "dm-", 3) && isdigit(name[3])) {
> +                        scan_dir_for_dev("/dev/mapper", makedev(major, minor), &devname);
> +                	if (devname)
> +				snprintf(dev->dev_name, sizeof(dev->dev_name), "%s", devname);
> +			else
> +				snprintf(dev->dev_name, sizeof(dev->dev_name), "/dev/%s", name);
> +
> +        	} else {
> +			snprintf(dev->dev_name, sizeof(dev->dev_name), "/dev/%s", name);
> +		}
> +
>  		list_add_tail(&(dev->list), dev_list);
>  	}
>  
>