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ash: fix var_leak.tests so that it actually catches the NOFORK bug

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+ document the bug better

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko 2010-05-18 16:13:56 +02:00
parent c7f95d23f6
commit 42c4b2e3b5
3 changed files with 21 additions and 9 deletions
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22
shell/ash.c
View File

@ -9179,12 +9179,14 @@ evalcommand(union node *cmd, int flags)
/* Execute the command. */ /* Execute the command. */
switch (cmdentry.cmdtype) { switch (cmdentry.cmdtype) {
default: default: {
#if ENABLE_FEATURE_SH_NOFORK #if ENABLE_FEATURE_SH_NOFORK
/* Hmmm... shouldn't it happen somewhere in forkshell() instead? /* (1) BUG: if variables are set, we need to fork, or save/restore them
* Why "fork off a child process if necessary" doesn't apply to NOFORK? */ * around run_nofork_applet() call.
{ * (2) Should this check also be done in forkshell()?
* (perhaps it should, so that "VAR=VAL nofork" at least avoids exec...)
*/
/* find_command() encodes applet_no as (-2 - applet_no) */ /* find_command() encodes applet_no as (-2 - applet_no) */
int applet_no = (- cmdentry.u.index - 2); int applet_no = (- cmdentry.u.index - 2);
if (applet_no >= 0 && APPLET_IS_NOFORK(applet_no)) { if (applet_no >= 0 && APPLET_IS_NOFORK(applet_no)) {
@ -9193,10 +9195,13 @@ evalcommand(union node *cmd, int flags)
exitstatus = run_nofork_applet(applet_no, argv); exitstatus = run_nofork_applet(applet_no, argv);
break; break;
} }
}
#endif #endif
/* Fork off a child process if necessary. */ /* Can we avoid forking off? For example, very last command
* in a script or a subshell does not need forking,
* we can just exec it.
*/
if (!(flags & EV_EXIT) || may_have_traps) { if (!(flags & EV_EXIT) || may_have_traps) {
/* No, forking off a child is necessary */
INT_OFF; INT_OFF;
jp = makejob(/*cmd,*/ 1); jp = makejob(/*cmd,*/ 1);
if (forkshell(jp, cmd, FORK_FG) != 0) { if (forkshell(jp, cmd, FORK_FG) != 0) {
@ -9213,7 +9218,7 @@ evalcommand(union node *cmd, int flags)
listsetvar(varlist.list, VEXPORT|VSTACK); listsetvar(varlist.list, VEXPORT|VSTACK);
shellexec(argv, path, cmdentry.u.index); shellexec(argv, path, cmdentry.u.index);
/* NOTREACHED */ /* NOTREACHED */
} /* default */
case CMDBUILTIN: case CMDBUILTIN:
cmdenviron = varlist.list; cmdenviron = varlist.list;
if (cmdenviron) { if (cmdenviron) {
@ -9258,7 +9263,8 @@ evalcommand(union node *cmd, int flags)
if (evalfun(cmdentry.u.func, argc, argv, flags)) if (evalfun(cmdentry.u.func, argc, argv, flags))
goto raise; goto raise;
break; break;
}
} /* switch */
out: out:
popredir(/*drop:*/ cmd_is_exec, /*restore:*/ cmd_is_exec); popredir(/*drop:*/ cmd_is_exec, /*restore:*/ cmd_is_exec);

1
shell/ash_test/ash-vars/var_leak.right
View File

@ -1,3 +1,4 @@
should be empty: '' should be empty: ''
should be empty: ''
should be not empty: 'val2' should be not empty: 'val2'
should be not empty: 'val3' should be not empty: 'val3'

7
shell/ash_test/ash-vars/var_leak.tests
View File

@ -1,6 +1,11 @@
# true is a regular builtin, varibale should not leak out of it # cat is an external program, variable should not leak out of it.
# this currently fails with CONFIG_FEATURE_SH_NOFORK=y # this currently fails with CONFIG_FEATURE_SH_NOFORK=y
VAR='' VAR=''
VAR=val0 cat /dev/null
echo "should be empty: '$VAR'"
# true is a regular builtin, variable should not leak out of it.
VAR=''
VAR=val1 true VAR=val1 true
echo "should be empty: '$VAR'" echo "should be empty: '$VAR'"