Re: [Libguestfs] [PATCH nbdkit 1/2] file: Add an internal "mode"

On 08/17/22 17:38, Richard W.M. Jones wrote: > Previously we relied on the implicit assumption filename xor directory, > representing two modes. Make this explicit with an internal mode > variable. > > This is just refactoring and should not change the functionality. > However we're now more strict about duplicate file= or dir= parameters > appearing on the command line. Previously only the last one had an > effect and the others were silently ignored. Now we give an error in > this case. eg this worked before but now gives an error: > > $ ./nbdkit file /var/tmp /var/tmp/fedora-36.img > nbdkit: error: file|dir parameter can only appear once on the command line > --- > plugins/file/file.c | 124 +++++++++++++++++++++++++++----------------- > 1 file changed, 76 insertions(+), 48 deletions(-) > > diff --git a/plugins/file/file.c b/plugins/file/file.c > index aefca9ee2..f673ec132 100644 > --- a/plugins/file/file.c > +++ b/plugins/file/file.c > @@ -70,6 +70,7 @@ > #include "isaligned.h" > #include "fdatasync.h" > > +static enum { mode_none, mode_filename, mode_directory } mode = mode_none; > static char *filename = NULL; > static char *directory = NULL; > > @@ -180,14 +181,23 @@ file_config (const char *key, const char *value) > * existence checks to the last possible moment. > */ > if (strcmp (key, "file") == 0) { > - free (filename); > + if (mode != mode_none) { > + wrong_mode: *shudder* please move error handling sections to the end of the function. It's OK to jump forward in exceptional cases, but crossing jump lines (i.e. improper balancing / nesting) and backward jumps for error handling are terrible.