diff options
| -rw-r--r-- | shell/ash.c | 22 | ||||
| -rw-r--r-- | shell/ash_test/ash-vars/var_leak.right | 1 | ||||
| -rwxr-xr-x | shell/ash_test/ash-vars/var_leak.tests | 7 |
3 files changed, 21 insertions, 9 deletions
diff --git a/shell/ash.c b/shell/ash.c index d082333..83886c6 100644 --- a/shell/ash.c +++ b/shell/ash.c @@ -9179,12 +9179,14 @@ evalcommand(union node *cmd, int flags) /* Execute the command. */ switch (cmdentry.cmdtype) { - default: + default: { #if ENABLE_FEATURE_SH_NOFORK -/* Hmmm... shouldn't it happen somewhere in forkshell() instead? - * Why "fork off a child process if necessary" doesn't apply to NOFORK? */ - { +/* (1) BUG: if variables are set, we need to fork, or save/restore them + * 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) */ int applet_no = (- cmdentry.u.index - 2); 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); break; } - } #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) { + /* No, forking off a child is necessary */ INT_OFF; jp = makejob(/*cmd,*/ 1); if (forkshell(jp, cmd, FORK_FG) != 0) { @@ -9213,7 +9218,7 @@ evalcommand(union node *cmd, int flags) listsetvar(varlist.list, VEXPORT|VSTACK); shellexec(argv, path, cmdentry.u.index); /* NOTREACHED */ - + } /* default */ case CMDBUILTIN: cmdenviron = varlist.list; if (cmdenviron) { @@ -9258,7 +9263,8 @@ evalcommand(union node *cmd, int flags) if (evalfun(cmdentry.u.func, argc, argv, flags)) goto raise; break; - } + + } /* switch */ out: popredir(/*drop:*/ cmd_is_exec, /*restore:*/ cmd_is_exec); diff --git a/shell/ash_test/ash-vars/var_leak.right b/shell/ash_test/ash-vars/var_leak.right index be78112..01a5e32 100644 --- a/shell/ash_test/ash-vars/var_leak.right +++ b/shell/ash_test/ash-vars/var_leak.right @@ -1,3 +1,4 @@ should be empty: '' +should be empty: '' should be not empty: 'val2' should be not empty: 'val3' diff --git a/shell/ash_test/ash-vars/var_leak.tests b/shell/ash_test/ash-vars/var_leak.tests index 0320592..5242e24 100755 --- a/shell/ash_test/ash-vars/var_leak.tests +++ b/shell/ash_test/ash-vars/var_leak.tests @@ -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 VAR='' +VAR=val0 cat /dev/null +echo "should be empty: '$VAR'" + +# true is a regular builtin, variable should not leak out of it. +VAR='' VAR=val1 true echo "should be empty: '$VAR'" |