diff options
| author | Denys Vlasenko <vda.linux@googlemail.com> | 2025-08-14 12:03:24 +0200 |
|---|---|---|
| committer | Denys Vlasenko <vda.linux@googlemail.com> | 2025-08-14 12:03:24 +0200 |
| commit | cad5a79bd4e8ceef4a68f1551fd2b25122bcb1c8 (patch) | |
| tree | 07a542ea9ee47b56f69122ed66dea7ed8e6c1925 | |
| parent | 4343ca9aa879cabc52ff82c0a46d3ba20d7fec5c (diff) | |
hush: explain "empty quoted str marker" trick
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
| -rw-r--r-- | shell/hush.c | 16 |
1 files changed, 11 insertions, 5 deletions
diff --git a/shell/hush.c b/shell/hush.c index d65da3b98..002140b1a 100644 --- a/shell/hush.c +++ b/shell/hush.c @@ -5656,15 +5656,20 @@ static struct pipe *parse_stream(char **pstring, nommu_addchr(&ctx.as_string, ch); if (ch == '\'') { ctx.word.has_quoted_part = 1; - next = i_getch(input); - if (next == '\'' && !ctx.pending_redirect/*why?*/) { + ch = i_getch(input); + if (ch == '\'' && !ctx.pending_redirect/*why?*/) { insert_empty_quoted_str_marker: - nommu_addchr(&ctx.as_string, next); + nommu_addchr(&ctx.as_string, ch); +//Just inserting nothing doesn't work: consider +// CMD $EMPTYVAR +// CMD '' +//At execution time both will expand argv[1] to empty string +//and thus the argument will "vanish". +//But for second CMD, it should not vanish! o_addchr(&ctx.word, SPECIAL_VAR_SYMBOL); o_addchr(&ctx.word, SPECIAL_VAR_SYMBOL); continue; /* get next char */ } - ch = next; while (1) { if (ch == EOF) { syntax_error_unterm_ch('\''); @@ -5789,6 +5794,7 @@ static struct pipe *parse_stream(char **pstring, if ((ctx.is_assignment == MAYBE_ASSIGNMENT || ctx.is_assignment == WORD_IS_KEYWORD) && ch == '=' + // && !ctx.word.has_quoted_part // unnecessary, "empty quoted str marker" trick handles this too && endofname(ctx.word.data)[0] == '=' ) { ctx.is_assignment = DEFINITELY_ASSIGNMENT; @@ -5983,7 +5989,7 @@ static struct pipe *parse_stream(char **pstring, case '"': ctx.word.has_quoted_part = 1; if (next == '"' && !ctx.pending_redirect) { - i_getch(input); /* eat second " */ + ch = i_getch(input); /* eat second " */ goto insert_empty_quoted_str_marker; } if (ctx.is_assignment == NOT_ASSIGNMENT) |