afdcd12ed
Denis Vlasenko
2008-07-05
Subject
hush: fix a case where "$@" must expand to no word at all
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shell/hush.c +20 -6shell/hush_test/hush-parsing/starquoted2.right +2 -0shell/hush_test/hush-parsing/starquoted2.tests +14 -0
shell/hush.c+20 -6
| @@ -2380,7 +2380,10 @@ static int expand_vars_to_list(o_string *output, int n, char *arg, char or_mask) | |
| p = strchr(p, SPECIAL_VAR_SYMBOL); | |
| first_ch = arg[0] | or_mask; /* forced to "quoted" if or_mask = 0x80 */ | |
| - | ored_ch |= first_ch; |
| + | /* "$@" is special. Even if quoted, it can still |
| + | * expand to nothing (not even an empty string) */ |
| + | if ((first_ch & 0x7f) != '@') |
| + | ored_ch |= first_ch; |
| val = NULL; | |
| switch (first_ch & 0x7f) { | |
| /* Highest bit in first_ch indicates that var is double-quoted */ | |
| @@ -2401,6 +2404,7 @@ static int expand_vars_to_list(o_string *output, int n, char *arg, char or_mask) | |
| i = 1; | |
| if (!global_argv[i]) | |
| break; | |
| + | ored_ch |= first_ch; /* do it for "$@" _now_, when we know it's not empty */ |
| if (!(first_ch & 0x80)) { /* unquoted $* or $@ */ | |
| smallint sv = output->o_quote; | |
| /* unquoted var's contents should be globbed, so don't quote */ | |
| @@ -2932,15 +2936,25 @@ static int done_word(o_string *word, struct p_context *ctx) | |
| } | |
| } | |
| #endif | |
| - | if (word->nonnull /* we saw "xx" or 'xx' */ |
| + | if (word->nonnull /* word had "xx" or 'xx' at least as part of it */ |
| /* optimization: and if it's ("" or '') or ($v... or `cmd`...): */ | |
| && (word->data[0] == '\0' || word->data[0] == SPECIAL_VAR_SYMBOL) | |
| /* (otherwise it's "abc".... and is already safe) */ | |
| ) { | |
| - | /* Insert "empty variable" reference, this makes |
| - | * e.g. "", $empty"" etc to not disappear */ |
| - | o_addchr(word, SPECIAL_VAR_SYMBOL); |
| - | o_addchr(word, SPECIAL_VAR_SYMBOL); |
| + | /* but exclude "$@"! it expands to no word despite "" */ |
| + | char *p = word->data; |
| + | while (p[0] == SPECIAL_VAR_SYMBOL |
| + | && (p[1] & 0x7f) == '@' |
| + | && p[2] == SPECIAL_VAR_SYMBOL |
| + | ) { |
| + | p += 3; |
| + | } |
| + | if (p == word->data || p[0] != '\0') { |
| + | /* Insert "empty variable" reference, this makes |
| + | * e.g. "", $empty"" etc to not disappear */ |
| + | o_addchr(word, SPECIAL_VAR_SYMBOL); |
| + | o_addchr(word, SPECIAL_VAR_SYMBOL); |
| + | } |
| } | |
| child->argv = add_malloced_string_to_strings(child->argv, xstrdup(word->data)); | |
| debug_print_strings("word appended to argv", child->argv); | |
shell/hush_test/hush-parsing/starquoted2.right+2 -0
| @@ -0,0 +1,2 @@ | |
| + | Should be printed |
| + | Should be printed |
shell/hush_test/hush-parsing/starquoted2.tests+14 -0
| @@ -0,0 +1,14 @@ | |
| + | if test $# != 0; then |
| + | exec "$THIS_SH" "$0" |
| + | fi |
| + | |
| + | # No params! |
| + | for a in "$*"; do echo Should be printed; done |
| + | for a in "$@"; do echo Should not be printed; done |
| + | # Yes, believe it or not, bash is mesmerized by "$@" and stops |
| + | # treating "" as "this word cannot be expanded to nothing, |
| + | # but must be at least null string". Now it can be expanded to nothing. |
| + | for a in "$@"""; do echo Should not be printed; done |
| + | for a in """$@"; do echo Should not be printed; done |
| + | for a in """$@"''"$@"''; do echo Should not be printed; done |
| + | for a in ""; do echo Should be printed; done |