On Wed, May 26, 2010 at 09:00:31PM +1000, Herbert Xu wrote:
> [VAR] Add localvars nesting
> This patch adds localvars nesting infrastructure so we can reuse
> the localvars mechanism for command evaluation.
localvars could already nest, it's just that this change makes the
nesting explicit instead of on the C stack.
Further comments inline.
> Signed-off-by: Herbert Xu <herb...@gondor.apana.org.au>
> ---
> ChangeLog | 4 ++++
> src/eval.c | 7 ++-----
> src/var.c | 50 ++++++++++++++++++++++++++++++++++++++++++++------
> src/var.h | 1 +
> 4 files changed, 51 insertions(+), 11 deletions(-)
> diff --git a/ChangeLog b/ChangeLog
> index ee78154..7285a23 100644
> --- a/ChangeLog
> +++ b/ChangeLog
> @@ -1,3 +1,7 @@
> +2010-05-24 Herbert Xu <herb...@gondor.apana.org.au>
> +
> + * Add localvars nesting.
> +
> 2010-05-03 Gerrit Pape <p...@smarden.org>
>
> * Fix command -- crash.
> diff --git a/src/eval.c b/src/eval.c
> index 62d9d5d..8d2767c 100644
> --- a/src/eval.c
> +++ b/src/eval.c
> @@ -928,20 +928,17 @@ STATIC int
> evalfun(struct funcnode *func, int argc, char **argv, int flags)
> {
> volatile struct shparam saveparam;
> - struct localvar *volatile savelocalvars;
> struct jmploc *volatile savehandler;
> struct jmploc jmploc;
> int e;
>
> saveparam = shellparam;
> - savelocalvars = localvars;
> if ((e = setjmp(jmploc.loc))) {
> goto funcdone;
> }
> INTOFF;
> savehandler = handler;
> handler = &jmploc;
> - localvars = NULL;
> shellparam.malloc = 0;
> func->count++;
> funcnest++;
> @@ -950,13 +947,13 @@ evalfun(struct funcnode *func, int argc, char **argv,
> int flags)
> shellparam.p = argv + 1;
> shellparam.optind = 1;
> shellparam.optoff = -1;
> + pushlocalvars();
> evaltree(&func->n, flags & EV_TESTED);
> + poplocalvars();
> funcdone:
> INTOFF;
> funcnest--;
> freefunc(func);
> - poplocalvars();
> - localvars = savelocalvars;
> freeparam(&shellparam);
> shellparam = saveparam;
> handler = savehandler;
This change does not do poplocalvars() if the function was exited with
an error. While this is normally not a problem because the shell exits
or executes the RESET actions, 'command eval', 'command .' and 'fc' will
"catch" any errors and continue normally.
Example (with the below "disallow local outside a function" change):
dash -c 'f() { unset xyz; ${xyz?}; }; command eval f; local i'
> diff --git a/src/var.c b/src/var.c
> index 2737fb1..de1a5f5 100644
> [...]
> @@ -446,6 +456,9 @@ localcmd(int argc, char **argv)
> {
> char *name;
>
> + if (!localvar_stack)
> + sh_error("not in a function");
> +
> argv = argptr;
> while ((name = *argv++) != NULL) {
> mklocal(name);
This change (failing local outside functions), while a good idea, should
be mentioned in the commit message/changelog, as it might break certain
scripts.
(Note that in mksh local is an alias for typeset, which will work
outside functions.)
--
Jilles Tjoelker
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