41d8f1081
Denys Vlasenko
2018-04-05
Subject
hush: fix corner cases with exec in empty expansions
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shell/ash_test/ash-redir/redir_exec1.right +2 -0shell/ash_test/ash-redir/redir_exec1.tests +2 -0shell/hush.c +26 -17shell/hush_test/hush-redir/redir_exec1.right +3 -0shell/hush_test/hush-redir/redir_exec1.tests +2 -0
shell/ash_test/ash-redir/redir_exec1.right+2 -0
| @@ -0,0 +1,2 @@ | |
| + | redir_exec1.tests: line 1: can't create /cant/be/created: nonexistent directory |
| + | First |
shell/ash_test/ash-redir/redir_exec1.tests+2 -0
| @@ -0,0 +1,2 @@ | |
| + | v=`echo First >&2` exec >/cant/be/created |
| + | echo One:$? |
shell/hush.c+26 -17
| @@ -8200,19 +8200,21 @@ static int redirect_and_varexp_helper( | |
| struct squirrel **sqp, | |
| char **argv_expanded) | |
| { | |
| + | /* Assignments occur before redirects. Try: |
| + | * a=`sleep 1` sleep 2 3>/qwe/rty |
| + | */ |
| + | |
| + | char **new_env = expand_assignments(command->argv, command->assignment_cnt); |
| + | dump_cmd_in_x_mode(new_env); |
| + | dump_cmd_in_x_mode(argv_expanded); |
| + | /* this takes ownership of new_env[i] elements, and frees new_env: */ |
| + | set_vars_and_save_old(new_env); |
| + | |
| /* setup_redirects acts on file descriptors, not FILEs. | |
| * This is perfect for work that comes after exec(). | |
| * Is it really safe for inline use? Experimentally, | |
| * things seem to work. */ | |
| - | int rcode = setup_redirects(command, sqp); |
| - | if (rcode == 0) { |
| - | char **new_env = expand_assignments(command->argv, command->assignment_cnt); |
| - | dump_cmd_in_x_mode(new_env); |
| - | dump_cmd_in_x_mode(argv_expanded); |
| - | /* this takes ownership of new_env[i] elements, and frees new_env: */ |
| - | set_vars_and_save_old(new_env); |
| - | } |
| - | return rcode; |
| + | return setup_redirects(command, sqp); |
| } | |
| static NOINLINE int run_pipe(struct pipe *pi) | |
| { | |
| @@ -8315,6 +8317,7 @@ static NOINLINE int run_pipe(struct pipe *pi) | |
| * Ensure redirects take effect (that is, create files). | |
| * Try "a=t >file" | |
| */ | |
| + | only_assignments: |
| G.expand_exitcode = 0; | |
| rcode = setup_redirects(command, &squirrel); | |
| @@ -8359,12 +8362,10 @@ static NOINLINE int run_pipe(struct pipe *pi) | |
| #endif | |
| argv_expanded = expand_strvec_to_strvec(argv + command->assignment_cnt); | |
| - | /* if someone gives us an empty string: `cmd with empty output` */ |
| - | //TODO: what about: var=EXPR `` >FILE ? will var be set? Will FILE be created? |
| + | /* If someone gives us an empty string: `cmd with empty output` */ |
| if (!argv_expanded[0]) { | |
| free(argv_expanded); | |
| - | debug_leave(); |
| - | return G.last_exitcode; |
| + | goto only_assignments; |
| } | |
| old_vars = NULL; | |
| @@ -8378,9 +8379,17 @@ static NOINLINE int run_pipe(struct pipe *pi) | |
| if (x || funcp) { | |
| if (x && x->b_function == builtin_exec && argv_expanded[1] == NULL) { | |
| debug_printf("exec with redirects only\n"); | |
| - | rcode = setup_redirects(command, NULL); |
| - | //TODO: what about: var=EXPR exec >FILE ? will var be set? |
| + | /* |
| + | * Variable assignments are executed, but then "forgotten": |
| + | * a=`sleep 1;echo A` exec 3>&-; echo $a |
| + | * sleeps, but prints nothing. |
| + | */ |
| + | enter_var_nest_level(); |
| + | G.shadowed_vars_pp = &old_vars; |
| + | rcode = redirect_and_varexp_helper(command, /*squirrel:*/ NULL, argv_expanded); |
| + | G.shadowed_vars_pp = sv_shadowed; |
| /* rcode=1 can be if redir file can't be opened */ | |
| + | |
| goto clean_up_and_ret1; | |
| } | |
| @@ -8452,9 +8461,10 @@ static NOINLINE int run_pipe(struct pipe *pi) | |
| } else | |
| goto must_fork; | |
| + | restore_redirects(squirrel); |
| + | clean_up_and_ret1: |
| leave_var_nest_level(); | |
| add_vars(old_vars); | |
| - | restore_redirects(squirrel); |
| /* | |
| * Try "usleep 99999999" + ^C + "echo $?" | |
| @@ -8474,7 +8484,6 @@ static NOINLINE int run_pipe(struct pipe *pi) | |
| if (sigismember(&G.pending_set, SIGINT)) | |
| rcode = 128 + SIGINT; | |
| } | |
| - | clean_up_and_ret1: |
| free(argv_expanded); | |
| IF_HAS_KEYWORDS(if (pi->pi_inverted) rcode = !rcode;) | |
| debug_leave(); | |
shell/hush_test/hush-redir/redir_exec1.right+3 -0
| @@ -0,0 +1,3 @@ | |
| + | First |
| + | hush: can't open '/cant/be/created': No such file or directory |
| + | One:1 |
shell/hush_test/hush-redir/redir_exec1.tests+2 -0
| @@ -0,0 +1,2 @@ | |
| + | v=`echo First >&2` exec >/cant/be/created |
| + | echo One:$? |