[Libguestfs] [libguestfs PATCH 6/7] lib: introduce guestfs_int_make_pid_path()

[Richard W.M. Jones]

On Thu, Jul 13, 2023 at 07:10:51PM +0200, Laszlo Ersek wrote:
> Introduce a small function for creating pathnames for PID files.
> 
> guestfs_int_make_pid_path() is something of an amalgamation of
> guestfs_int_make_temp_path() [1] and guestfs_int_create_socketname() [2]:
> 
> - it creates a pathname under sockdir, like [2],
> 
> - it uses the handle's unique counter, like [1],
> 
> - it takes a name like both [1] and [2], but the name is not size-limited
>   like in [2], plus we hardcode the suffix from [1] as ".pid".
> 
> Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2184967
> Signed-off-by: Laszlo Ersek <lersek at redhat.com>
> ---
>  lib/guestfs-internal.h |  1 +
>  lib/tmpdirs.c          | 15 +++++++++++++++
>  2 files changed, 16 insertions(+)
> 
> diff --git a/lib/guestfs-internal.h b/lib/guestfs-internal.h
> index 2ee16ea1e75a..9ba4d4ad46cf 100644
> --- a/lib/guestfs-internal.h
> +++ b/lib/guestfs-internal.h
> @@ -669,6 +669,7 @@ extern int guestfs_int_lazy_make_tmpdir (guestfs_h *g);
>  extern int guestfs_int_lazy_make_sockdir (guestfs_h *g);
>  extern char *guestfs_int_make_temp_path (guestfs_h *g, const char *name, const char *extension);
>  extern int guestfs_int_create_socketname (guestfs_h *g, const char *filename, char (*sockname)[UNIX_PATH_MAX]);
> +extern char *guestfs_int_make_pid_path (guestfs_h *g, const char *name);
>  extern char *guestfs_int_lazy_make_supermin_appliance_dir (guestfs_h *g);
>  extern void guestfs_int_remove_tmpdir (guestfs_h *g);
>  extern void guestfs_int_remove_sockdir (guestfs_h *g);
> diff --git a/lib/tmpdirs.c b/lib/tmpdirs.c
> index 24adf98daee0..22b8f54b0693 100644
> --- a/lib/tmpdirs.c
> +++ b/lib/tmpdirs.c
> @@ -279,6 +279,21 @@ guestfs_int_create_socketname (guestfs_h *g, const char *filename,
>    return 0;
>  }
>  
> +/**
> + * Generate unique paths for PID files.
> + *
> + * Returns a unique path or NULL on error.  On success, the pathname points
> + * under sockdir and not tmpdir; daemons that write PID files after dropping
> + * privileges may not have access to tmpdir.
> + */
> +char *
> +guestfs_int_make_pid_path (guestfs_h *g, const char *name)
> +{
> +  if (guestfs_int_lazy_make_sockdir (g) < 0)
> +    return NULL;
> +  return safe_asprintf (g, "%s/%s%d.pid", g->sockdir, name, ++g->unique);
> +}
> +
>  /**
>   * Create the supermin appliance directory under cachedir, if it does
>   * not exist.

Reviewed-by: Richard W.M. Jones <rjones at redhat.com>

-- 
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