diff options
Diffstat (limited to 'src/bfstd.c')
| -rw-r--r-- | src/bfstd.c | 178 |
1 files changed, 101 insertions, 77 deletions
diff --git a/src/bfstd.c b/src/bfstd.c index e125be6..6f39f54 100644 --- a/src/bfstd.c +++ b/src/bfstd.c @@ -593,34 +593,8 @@ static size_t printable_len(const char *str, size_t len) { return cur - str; } -/** Get the length of the longest unprintable prefix of a string. */ -static size_t unprintable_len(const char *str, size_t len) { - mbstate_t mb; - memset(&mb, 0, sizeof(mb)); - - const char *cur = str; - while (len > 0) { - wchar_t wc; - size_t mblen = mbrtowc(&wc, cur, len, &mb); - if (mblen == (size_t)-1) { - // Invalid byte sequence, try again from the next byte - mblen = 1; - } else if (mblen == (size_t)-2) { - // Incomplete byte sequence, the rest is unprintable - mblen = len; - } else if (iswprint(wc)) { - break; - } - - cur += mblen; - len -= mblen; - } - - return cur - str; -} - /** Convert a special char into a well-known escape sequence like "\n". */ -static const char *c_esc(char c) { +static const char *dollar_esc(char c) { // https://www.gnu.org/software/bash/manual/html_node/ANSI_002dC-Quoting.html switch (c) { case '\a': @@ -639,73 +613,123 @@ static const char *c_esc(char c) { return "\\t"; case '\v': return "\\v"; + case '\'': + return "\\'"; + case '\\': + return "\\\\"; default: return NULL; } } -char *wordesc(const char *str) { - size_t len = strlen(str); +/** $'Quote' a string for the shell. */ +static char *dollar_quote(char *dest, char *end, const char *str, size_t len) { + static const char *hex[] = {"0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "A", "B", "C", "D", "E", "F"}; - // Worst case: every char is replaced with $'\xXX', so at most a 7x growth - size_t max_size = 7 * len + 3; - char *ret = malloc(max_size); - if (!ret) { - return NULL; - } - char *cur = ret; - char *end = ret + max_size; + dest = xstpecpy(dest, end, "$'"); while (len > 0) { size_t plen = printable_len(str, len); - if (strcspn(str, "|&;<>()$`\\\"' *?[#˜=%!") >= plen) { - // Whole chunk is safe - // https://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_02 - cur = xstpencpy(cur, end, str, plen); - } else if (strcspn(str, "`$\\\"!") >= plen) { - // Safe to double-quote the whole chunk - // https://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_02_03 - cur = xstpecpy(cur, end, "\""); - cur = xstpencpy(cur, end, str, plen); - cur = xstpecpy(cur, end, "\""); + size_t elen = strcspn(str, "'\\"); + size_t min = plen < elen ? plen : elen; + dest = xstpencpy(dest, end, str, min); + str += min; + len -= min; + if (len == 0) { + break; + } + + unsigned char byte = *str; + ++str; + --len; + + const char *esc = dollar_esc(byte); + if (esc) { + dest = xstpecpy(dest, end, esc); } else { - // Single-quote the whole chunk, convert ' into '\'' - cur = xstpecpy(cur, end, "'"); - for (size_t i = 0; i < plen; ++i) { - if (str[i] == '\'') { - cur = xstpecpy(cur, end, "'\\''"); - } else { - cur = xstpencpy(cur, end, &str[i], 1); - } - } - cur = xstpecpy(cur, end, "'"); + dest = xstpecpy(dest, end, "\\x"); + dest = xstpecpy(dest, end, hex[byte / 0x10]); + dest = xstpecpy(dest, end, hex[byte % 0x10]); } + } - str += plen; - len -= plen; - if (len == 0) { - break; + return xstpecpy(dest, end, "'"); +} + +/** How much of this string is safe as a bare word? */ +static size_t bare_len(const char *str) { + // https://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_02 + return strcspn(str, "|&;<>()$`\\\"' *?[#˜=%!"); +} + +/** How much of this string is safe to double-quote? */ +static size_t quotable_len(const char *str) { + // https://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_02_03 + return strcspn(str, "`$\\\"!"); +} + +/** "Quote" a string for the shell. */ +static char *double_quote(char *dest, char *end, const char *str) { + dest = xstpecpy(dest, end, "\""); + dest = xstpecpy(dest, end, str); + return xstpecpy(dest, end, "\""); +} + +/** 'Quote' a string for the shell. */ +static char *single_quote(char *dest, char *end, const char *str) { + bool open = false; + + while (*str) { + size_t len = strcspn(str, "'"); + if (len > 0) { + if (!open) { + dest = xstpecpy(dest, end, "'"); + open = true; + } + dest = xstpencpy(dest, end, str, len); + str += len; } - // Non-printable characters, write them as $'\xXX\xXX...' - cur = xstpecpy(cur, end, "$'"); - size_t uplen = unprintable_len(str, len); - for (size_t i = 0; i < uplen; ++i) { - const char *esc = c_esc(str[i]); - if (esc) { - cur = xstpecpy(cur, end, esc); - } else { - static const char *hex[] = {"0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "A", "B", "C", "D", "E", "F"}; - unsigned char byte = str[i]; - cur = xstpecpy(cur, end, "\\x"); - cur = xstpecpy(cur, end, hex[byte / 0x10]); - cur = xstpecpy(cur, end, hex[byte % 0x10]); + while (*str == '\'') { + if (open) { + dest = xstpecpy(dest, end, "'"); + open = false; } + dest = xstpecpy(dest, end, "\\'"); + ++str; } - cur = xstpecpy(cur, end, "'"); + } - str += uplen; - len -= uplen; + if (open) { + dest = xstpecpy(dest, end, "'"); + } + return dest; +} + +char *wordesc(const char *str) { + size_t len = strlen(str); + + // Worst case: every char is replaced with $'\xXX', so at most a 7x growth + size_t max_size = 7 * len + 3; + char *ret = malloc(max_size); + if (!ret) { + return NULL; + } + char *cur = ret; + char *end = ret + max_size; + + if (printable_len(str, len) < len) { + // String contains unprintable chars, use $'this\x7Fsyntax' + cur = dollar_quote(cur, end, str, len); + } else if (bare_len(str) == len) { + // Whole string is safe as a bare word + cur = xstpecpy(cur, end, str); + } else if (quotable_len(str) == len) { + // Whole string is safe to double-quote + cur = double_quote(cur, end, str); + } else { + // Single-quote the whole string + cur = single_quote(cur, end, str); } if (cur == ret) { |