Re: [Libguestfs] [PATCH 1/3] launch: add internal helper for socket paths creation

On Wed, Feb 03, 2016 at 10:35:07AM +0100, Pino Toscano wrote: > On Tuesday 02 February 2016 19:47:12 Richard W.M. Jones wrote: > > On Tue, Feb 02, 2016 at 03:27:39PM +0100, Pino Toscano wrote: > > > diff --git a/src/launch.c b/src/launch.c > > > index f59818f..ec061e3 100644 > > > --- a/src/launch.c > > > +++ b/src/launch.c > > > @@ -418,6 +418,21 @@ guestfs_int_get_cpu_model (int kvm) > > > #endif > > > } > > > > > > +/* Create the path for a socket with the selected filename in the > > > + * tmpdir. > > > + */ > > > +int > > > +guestfs_int_create_socketname (guestfs_h *g, const char *filename, > > > + char (*sockpath)[UNIX_PATH_MAX]) > > > +{ > > > + char *path = g->tmpdir; > > > + > > > + snprintf (*sockpath, UNIX_PATH_MAX-1, "%s/%s", path, filename); > > > + (*sockpath)[UNIX_PATH_MAX-1] = '\0'; > > > > What's wrong with: > > > > snprintf (*sockpath, UNIX_PATH_MAX, "%s/%s", path, filename); > > If the "$path/$filename" string is longer than UNIX_PATH_MAX, then > *sockpath won't be 0-terminated. That's not true though: --------------------------------------------------------- test.c ----- #include <stdio.h> #include <stdlib.h> int main () { char s[10]; snprintf (s, sizeof s, "%s", "0123456789"); printf ("s = %s\n", s); return 0; } ---------------------------------------------------------------------- $ gcc -Wall test.c -o test $ ./test s = 012345678