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authorGravatar Ron Yorston <rmy@pobox.com>2019-02-25 08:29:38 +0000
committerGravatar Denys Vlasenko <vda.linux@googlemail.com>2019-02-25 18:57:59 +0100
commitf55161ad27b641f6e09c6c498fa8a2bdb1112b0a (patch)
tree8ea2b3a9922ffd0b3fc8b47b7a997130e80bb7ce /shell
parente563f9e851c78f5c13cb9828ddb11ca981fd6331 (diff)
downloadbusybox-f55161ad27b641f6e09c6c498fa8a2bdb1112b0a.tar.gz
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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>
Diffstat (limited to 'shell')
-rw-r--r--shell/ash.c14
1 files changed, 4 insertions, 10 deletions
diff --git a/shell/ash.c b/shell/ash.c
index a284b084d..a4394d756 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;
}