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| author | Ron Yorston | 2019-02-25 08:29:38 +0000 |
|---|---|---|
| committer | Denys Vlasenko | 2019-02-25 18:57:59 +0100 |
| commit | f55161ad27b641f6e09c6c498fa8a2bdb1112b0a (patch) | |
| tree | 8ea2b3a9922ffd0b3fc8b47b7a997130e80bb7ce | |
| parent | e563f9e851c78f5c13cb9828ddb11ca981fd6331 (diff) | |
| download | busybox-f55161ad27b641f6e09c6c498fa8a2bdb1112b0a.zip busybox-f55161ad27b641f6e09c6c498fa8a2bdb1112b0a.tar.gz | |
ash: eval: avoid leaking memory associated with redirections. Closes 7748
The following constructs result in ever-increasing memory usage:
while true; do { true; } </dev/null; done
while true; do ( true; ) </dev/null; done
For comparison, bash displays static memory usage in both cases.
This has been fixed in dash by commit 2bc6caa. The maintainer
writes:
I have simplified evaltree so that it simply sets the stack mark
unconditionally. This allows us to remove the stack marks in the
functions called by evaltree.
Closes BusyBox bug 7748.
function old new delta
evaltree 606 632 +26
evalcommand 1724 1696 -28
evalcase 382 351 -31
evalfor 230 196 -34
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 1/3 up/down: 26/-93) Total: -67 bytes
Signed-off-by: Ron Yorston <rmy@pobox.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
| -rw-r--r-- | shell/ash.c | 14 |
1 files changed, 4 insertions, 10 deletions
diff --git a/shell/ash.c b/shell/ash.c index a284b08..a4394d7 100644 --- a/shell/ash.c +++ b/shell/ash.c @@ -9034,8 +9034,11 @@ evaltree(union node *n, int flags) { int checkexit = 0; int (*evalfn)(union node *, int); + struct stackmark smark; int status = 0; + setstackmark(&smark); + if (n == NULL) { TRACE(("evaltree(NULL) called\n")); goto out; @@ -9149,6 +9152,7 @@ evaltree(union node *n, int flags) if (flags & EV_EXIT) raise_exception(EXEXIT); + popstackmark(&smark); TRACE(("leaving evaltree (no interrupts)\n")); return exitstatus; } @@ -9209,14 +9213,12 @@ evalfor(union node *n, int flags) struct arglist arglist; union node *argp; struct strlist *sp; - struct stackmark smark; int status = 0; errlinno = lineno = n->ncase.linno; if (funcline) lineno -= funcline - 1; - setstackmark(&smark); arglist.list = NULL; arglist.lastp = &arglist.list; for (argp = n->nfor.args; argp; argp = argp->narg.next) { @@ -9233,7 +9235,6 @@ evalfor(union node *n, int flags) break; } loopnest--; - popstackmark(&smark); return status; } @@ -9244,14 +9245,12 @@ evalcase(union node *n, int flags) union node *cp; union node *patp; struct arglist arglist; - struct stackmark smark; int status = 0; errlinno = lineno = n->ncase.linno; if (funcline) lineno -= funcline - 1; - setstackmark(&smark); arglist.list = NULL; arglist.lastp = &arglist.list; expandarg(n->ncase.expr, &arglist, EXP_TILDE); @@ -9270,8 +9269,6 @@ evalcase(union node *n, int flags) } } out: - popstackmark(&smark); - return status; } @@ -9970,7 +9967,6 @@ evalcommand(union node *cmd, int flags) struct localvar_list *localvar_stop; struct parsefile *file_stop; struct redirtab *redir_stop; - struct stackmark smark; union node *argp; struct arglist arglist; struct arglist varlist; @@ -9992,7 +9988,6 @@ evalcommand(union node *cmd, int flags) /* First expand the arguments. */ TRACE(("evalcommand(0x%lx, %d) called\n", (long)cmd, flags)); - setstackmark(&smark); localvar_stop = pushlocalvars(); file_stop = g_parsefile; back_exitstatus = 0; @@ -10275,7 +10270,6 @@ evalcommand(union node *cmd, int flags) */ setvar0("_", lastarg); } - popstackmark(&smark); return status; } |