0fcc7f5f7
Denys Vlasenko
2021-12-28
Subject
scripts/echo.c: fix NUL handling in "abc\0 def"
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scripts/echo.c+21 -14
| @@ -153,25 +153,32 @@ int main(int argc, char **argv) | |
| if (!eflag) { | |
| /* optimization for very common case */ | |
| fputs(arg, stdout); | |
| - | } else while ((c = *arg++)) { |
| - | if (c == eflag) { /* Check for escape seq. */ |
| + | } else |
| + | while ((c = *arg++) != '\0') { |
| + | if (c == eflag) { |
| + | /* This is an "\x" sequence */ |
| + | |
| if (*arg == 'c') { | |
| - | /* '\c' means cancel newline and |
| + | /* "\c" means cancel newline and |
| * ignore all subsequent chars. */ | |
| goto ret; | |
| } | |
| - | { |
| - | /* Since SUSv3 mandates a first digit of 0, 4-digit octals |
| - | * of the form \0### are accepted. */ |
| - | if (*arg == '0') { |
| - | /* NB: don't turn "...\0" into "...\" */ |
| - | if (arg[1] && ((unsigned char)(arg[1]) - '0') < 8) { |
| - | arg++; |
| - | } |
| + | /* Since SUSv3 mandates a first digit of 0, 4-digit octals |
| + | * of the form \0### are accepted. */ |
| + | if (*arg == '0') { |
| + | if ((unsigned char)(arg[1] - '0') < 8) { |
| + | /* 2nd char is 0..7: skip leading '0' */ |
| + | arg++; |
| } | |
| - | /* bb_process_escape_sequence handles NUL correctly |
| - | * ("...\" case. */ |
| - | c = bb_process_escape_sequence(&arg); |
| + | } |
| + | /* bb_process_escape_sequence handles NUL correctly |
| + | * ("...\" case). */ |
| + | { |
| + | /* optimization: don't force arg to be on-stack, |
| + | * use another variable for that. ~30 bytes win */ |
| + | const char *z = arg; |
| + | c = bb_process_escape_sequence(&z); |
| + | arg = z; |
| } | |
| } | |
| putchar(c); | |