[Devel] [PATCH VZ10 v2 2/3] selftests/ve: Add more helpers

[Vasileios Almpanis]

> Some more read/write helpers may be useful.
> 
> Also, add a helper to execute functions in child process with
> switched namespaces and cgroup.
> 
> https://virtuozzo.atlassian.net/browse/VSTOR-144504
> 
> Feature: ve selftests
> Signed-off-by: Vladimir Riabchun <vladimir.riabchun at virtuozzo.com>
>
> diff --git a/tools/testing/selftests/ve/ve_selftest.h b/tools/testing/selftests/ve/ve_selftest.h
> index ee960f7db0b4..e88293a39d34 100644
> --- a/tools/testing/selftests/ve/ve_selftest.h
> +++ b/tools/testing/selftests/ve/ve_selftest.h
> @@ -168,6 +168,14 @@ static inline int write_file_at(int dirfd, const char *path, const char *val)
>  	return (ret == (int)len) ? 0 : -1;
>  }
>  
> +static inline int write_u64_at(int dirfd, const char *path, unsigned long long val)
> +{
> +	char s[32];
> +
> +	snprintf(s, sizeof(s), "%llu", val);
> +	return write_file_at(dirfd, path, s);
> +}
> +
>  static inline int read_file_at(int dirfd, const char *path, char *buf,
>  			       size_t buflen)
>  {
> @@ -198,14 +206,9 @@ static inline int read_u64_at(int dirfd, const char *path,
>  			      unsigned long long *out)
>  {
>  	char buf[32] = {0}, *end;
> -	int fd, ret;
> -
> -	fd = openat(dirfd, path, O_RDONLY);
> -	if (fd < 0)
> -		return -1;
> +	int ret;
>  
> -	ret = read(fd, buf, sizeof(buf) - 1);
> -	close(fd);
> +	ret = read_file_at(dirfd, path, buf, sizeof(buf));
>  	if (ret <= 0)
>  		return -1;
>  
> @@ -216,6 +219,25 @@ static inline int read_u64_at(int dirfd, const char *path,
>  	return 0;
>  }
>  
> +static inline int read_s32_at(int dirfd, const char *path,
> +			      int *out)
> +{
> +	char buf[32] = {0}, *end;
> +	long tmp;
> +	int ret;
> +
> +	ret = read_file_at(dirfd, path, buf, sizeof(buf));
> +	if (ret <= 0)
> +		return -1;
> +
> +	errno = 0;
> +	tmp = strtol(buf, &end, 10);
> +	if (errno || end == buf || tmp < INT_MIN || tmp > INT_MAX)
> +		return -1;
> +	*out = tmp;
> +	return 0;
> +}
> +
>  /* A fresh, private cgroup2 mount, returned as an fd to use with *at() calls. */
>  static inline int mount_cg2_fd(void)
>  {
> @@ -259,6 +281,55 @@ static inline int enter_cgroup(int cgv2_fd, int ctid)
>  	return ret;
>  }
>  
> +/*
> + * Run function in VE cgroup and new namespaces.
> + *
> + * Namespaces are provided via unshare_flags.

The documentation here is a bit weird. There is no unshare_flags
just flags and they are not passed to unshare but to enter_namespaces.

-- 
Vasileios Almpanis <vasileios.almpanis at virtuozzo.com>