[CRIU] [PATCH 1/2] zdtm: Add filesystem specific helpers

[Pavel Emelyanov]

On 09/04/2015 04:43 PM, Cyrill Gorcunov wrote:
> In particular we have to find out if we're
> running on btrfs filesystem for proper device
> number mangling.
> 
> Signed-off-by: Cyrill Gorcunov <gorcunov at openvz.org>
> ---
>  test/zdtm/lib/fs.c | 87 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  test/zdtm/lib/fs.h | 46 +++++++++++++++++++++++++++++
>  2 files changed, 133 insertions(+)
> 
> diff --git a/test/zdtm/lib/fs.c b/test/zdtm/lib/fs.c
> index 506580c8c180..04788e9c4539 100644
> --- a/test/zdtm/lib/fs.c
> +++ b/test/zdtm/lib/fs.c

I don't have such file in my git tree.

> @@ -5,6 +5,93 @@
>  #include <stdarg.h>
>  #include <errno.h>
>  #include <unistd.h>
> +#include <limits.h>
>  
>  #include "zdtmtst.h"
>  #include "fs.h"
> +
> +mnt_info_t *mnt_info_alloc(void)
> +{
> +	mnt_info_t *m = malloc(sizeof(*m));
> +	if (m)
> +		memset(m, 0, sizeof(*m));
> +	return m;
> +}
> +
> +void mnt_info_free(mnt_info_t **m)
> +{
> +	if (m && *m) {
> +		free(*m);
> +		*m = NULL;
> +	}
> +}
> +
> +mnt_info_t *get_cwd_mnt_info(void)
> +{
> +	int mnt_id, parent_mnt_id;
> +	unsigned int kmaj, kmin;
> +	char str[1024], *cwd;
> +	int ret;
> +	FILE *f;
> +
> +	mnt_info_t *m = NULL;
> +
> +	char mountpoint[PATH_MAX];
> +	char root[PATH_MAX];
> +
> +	char *fsname = NULL;
> +	size_t len = 0, best_len = 0;
> +
> +	f = fopen("/proc/self/mountinfo", "r");
> +	if (!f)
> +		return NULL;
> +
> +	cwd = get_current_dir_name();
> +	if (!cwd)
> +		goto err;
> +
> +	m = mnt_info_alloc();
> +	if (!m)
> +		goto err;
> +
> +	while (fgets(str, sizeof(str), f)) {
> +		char *hyphen = strchr(str, '-');
> +		ret = sscanf(str, "%i %i %u:%u %s %s",
> +			     &mnt_id, &parent_mnt_id,
> +			     &kmaj, &kmin,
> +			     root, mountpoint);
> +		if (ret != 6 || !hyphen)
> +			goto err;
> +		ret = sscanf(hyphen + 1, " %ms", &fsname);
> +		if (ret != 1)
> +			goto err;
> +
> +		len = strlen(mountpoint);
> +		if (!strncmp(mountpoint, cwd, len)) {
> +			if (len > best_len) {
> +				best_len = len;
> +
> +				m->mnt_id = mnt_id;
> +				m->parent_mnt_id = parent_mnt_id;
> +				m->s_dev = MKKDEV(kmaj, kmin);
> +
> +				strncpy(m->root, root, sizeof(m->root));
> +				strncpy(m->mountpoint, mountpoint, sizeof(m->mountpoint));
> +				strncpy(m->fsname, fsname, sizeof(m->fsname));
> +			}
> +		}
> +
> +		free(fsname);
> +		fsname = NULL;
> +	}
> +
> +out:
> +	free(cwd);
> +	fclose(f);
> +
> +	return m;
> +
> +err:
> +	mnt_info_free(&m);
> +	goto out;
> +}
> diff --git a/test/zdtm/lib/fs.h b/test/zdtm/lib/fs.h
> index b161ab184d49..c574709dcc33 100644
> --- a/test/zdtm/lib/fs.h
> +++ b/test/zdtm/lib/fs.h
> @@ -1,3 +1,49 @@
>  #ifndef ZDTM_FS_H_
>  #define ZDTM_FS_H_
> +
> +#define _BSD_SOURCE
> +#include <sys/types.h>
> +
> +#include <limits.h>
> +
> +#define KDEV_MINORBITS	20
> +#define KDEV_MINORMASK	((1UL << KDEV_MINORBITS) - 1)
> +#define MKKDEV(ma, mi)	(((ma) << KDEV_MINORBITS) | (mi))
> +
> +static inline unsigned int kdev_major(unsigned int kdev)
> +{
> +	return kdev >> KDEV_MINORBITS;
> +}
> +
> +static inline unsigned int kdev_minor(unsigned int kdev)
> +{
> +	return kdev & KDEV_MINORMASK;
> +}
> +
> +static inline dev_t kdev_to_odev(unsigned int kdev)
> +{
> +	/*
> +	 * New kernels encode devices in a new form.
> +	 * See kernel's fs/stat.c for details, there
> +	 * choose_32_64 helpers which are the key.
> +	 */
> +	unsigned major = kdev_major(kdev);
> +	unsigned minor = kdev_minor(kdev);
> +
> +	return makedev(major, minor);
> +}
> +
> +typedef struct {
> +	int			mnt_id;
> +	int			parent_mnt_id;
> +	unsigned int		s_dev;
> +	char			root[PATH_MAX];
> +	char			mountpoint[PATH_MAX];
> +	char			fsname[64];
> +} mnt_info_t;
> +
> +extern mnt_info_t *mnt_info_alloc(void);
> +extern void mnt_info_free(mnt_info_t **m);
> +extern mnt_info_t *get_cwd_mnt_info(void);
> +
>  #endif /* ZDTM_FS_H_ */
>