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authorTavian Barnes <tavianator@tavianator.com>2023-07-13 12:36:10 -0400
committerTavian Barnes <tavianator@tavianator.com>2023-07-13 16:01:00 -0400
commite79f0d038d3ce916e744fd111b70d687f699c0bd (patch)
tree9395a08fdbf8374fb1f373e69346ebcf26219e3a /src
parent36fed99f5929782b61018d2d2e5a2800fba5e530 (diff)
downloadbfs-e79f0d038d3ce916e744fd111b70d687f699c0bd.tar.xz
bfstd: Quote the whole string the same way in wordesc()
Diffstat (limited to 'src')
-rw-r--r--src/bfstd.c178
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) {