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add escaping of non-printable & non-ASCII characters to xvasprintf()

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This commit is contained in:
Oswald Buddenhagen 2022-05-03 19:28:26 +02:00
parent 57173bd289
commit 0079ec774a
1 changed files with 43 additions and 3 deletions
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46
src/util.c
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@ -189,6 +189,10 @@ sys_error( const char *msg, ... )
// Print backslash-escaped string literals. Note that this does not
// automatically add quotes around the printed string, so it is
// possible to concatenate multiple segments.
// - %!s
// Same as %\\s, but non-ASCII characters are (hex-)escaped as well.
// - %!&s
// Same as %!s, but linefeeds are also printed verbatim for legibility.
// TODO: Trade off segments vs. buffer capacity dynamically.
#define QPRINTF_SEGS 16
@ -238,6 +242,13 @@ xvasprintf( const char *fmt, va_list ap )
if (c == '\\') {
escaped = 1;
c = *++fmt;
} else if (c == '!') {
escaped = 2;
c = *++fmt;
if (c == '&') {
escaped = 3;
c = *++fmt;
}
}
if (c == 'c') {
if (d + 1 > ed)
@ -249,10 +260,39 @@ xvasprintf( const char *fmt, va_list ap )
if (escaped) {
char *bd = d;
for (l = 0; l < maxlen && (c = *s); l++, s++) {
if (d + 2 > ed)
oob();
if (c == '\\' || c == '"')
if (c == '\\' || c == '"') {
if (d >= ed)
oob();
*d++ = '\\';
} else if (escaped >= 2 && (c < 32 || c > 126)) {
switch (c) {
case '\r': c = 'r'; break;
case '\t': c = 't'; break;
case '\a': c = 'a'; break;
case '\b': c = 'b'; break;
case '\v': c = 'v'; break;
case '\f': c = 'f'; break;
case '\n':
if (escaped == 2) {
c = 'n';
break;
}
if (d + 2 >= ed)
oob();
*d++ = '\\';
*d++ = 'n';
*d++ = c; // Keep the actual line break for legibility.
continue;
default:
d += nfsnprintf( d, ed - d, "\\x%02x", (uchar)c );
continue;
}
if (d >= ed)
oob();
*d++ = '\\';
}
if (d >= ed)
oob();
*d++ = c;
}
l = d - bd;