[CRIU] [PATCH 1/5] util: Add mkdirpat_precise helper

[Pavel Tikhomirov]

On 2/22/19 7:02 PM, Cyrill Gorcunov wrote:
> To know where new dirents are created.
> 
> Signed-off-by: Cyrill Gorcunov <gorcunov at gmail.com>
> ---
>   criu/include/util.h |  6 +++++-
>   criu/util.c         | 26 ++++++++++++++++++++------
>   2 files changed, 25 insertions(+), 7 deletions(-)
> 
> diff --git a/criu/include/util.h b/criu/include/util.h
> index 57192c5f273d..694b5358cf68 100644
> --- a/criu/include/util.h
> +++ b/criu/include/util.h
> @@ -253,7 +253,11 @@ static inline bool issubpath(const char *path, const char *sub_path)
>   /*
>    * mkdir -p
>    */
> -int mkdirpat(int fd, const char *path, int mode);
> +int mkdirpat_precise(int fd, const char *path, int mode, const char **new);
> +static inline int mkdirpat(int fd, const char *path, int mode)
> +{
> +	return mkdirpat_precise(fd, path, mode, NULL);
> +}
>   
>   /*
>    * Tests whether a path is a prefix of another path. This is different than
> diff --git a/criu/util.c b/criu/util.c
> index 1cc4ecd4427e..8c1ee550983f 100644
> --- a/criu/util.c
> +++ b/criu/util.c
> @@ -1001,10 +1001,15 @@ struct vma_area *alloc_vma_area(void)
>   	return p;
>   }
>   

"i" and "pos" looks duplicating the meaning of each other, maybe we can 
do something like 
https://github.com/Snorch/criu/commit/9e141789698210d5b5ac6f50d36d4657603968a0 
to simplify mkdirpat?

> -int mkdirpat(int fd, const char *path, int mode)
> +/*
> + * Make the whole @path to the specified directory, report
> + * the position of newly created directories via @new.
> + */
> +int mkdirpat_precise(int fd, const char *path, int mode, const char **new)
>   {
> -	size_t i;
>   	char made_path[PATH_MAX], *pos;
> +	const char *where = path;
> +	size_t i;
>   
>   	if (strlen(path) >= PATH_MAX) {
>   		pr_err("path %s is longer than PATH_MAX\n", path);
> @@ -1021,18 +1026,27 @@ int mkdirpat(int fd, const char *path, int mode)
>   		pos = strchr(made_path + i, '/');
>   		if (pos)
>   			*pos = '\0';
> -		if (mkdirat(fd, made_path, mode) < 0 && errno != EEXIST) {
> -			int ret = -errno;
> -			pr_perror("couldn't mkdirpat directory %s", made_path);
> -			return ret;
> +		if (mkdirat(fd, made_path, mode) < 0) {
> +			if (errno == EEXIST) {
> +				where = path;
> +			} else {
> +				int ret = -errno;
> +				pr_perror("couldn't mkdirpat directory %s", made_path);
> +				return ret;
> +			}
>   		}
>   		if (pos) {
>   			*pos = '/';
>   			i = pos - made_path;
> +			if (where == path)
> +				where = &path[i+1];
>   		} else
>   			break;
>   	}
>   
> +	if (new)
> +		*new = where;
> +
>   	return 0;
>   }
>   
> 

-- 
Best regards, Tikhomirov Pavel
Software Developer, Virtuozzo.