From 023dd2c515be63ddb2f0b6a6f3bccab4cdf7a71c Mon Sep 17 00:00:00 2001 From: Phil Sutter Date: Fri, 25 Nov 2022 03:13:14 +0100 Subject: libxtables: xt_xlate_add() to take care of spacing Try to eliminate most of the whitespace issues by separating strings from separate xt_xlate_add() calls by whitespace if needed. Cover the common case of consecutive range, list or MAC/IP address printing by inserting whitespace only if the string to be appended starts with an alphanumeric character or a brace. The latter helps to make spacing in anonymous sets consistent. Provide *_nospc() variants which disable the auto-spacing for the mandatory exception to the rule. Make things round by dropping any trailing whitespace before returning the buffer via xt_xlate_get(). Signed-off-by: Phil Sutter --- libxtables/xtables.c | 58 ++++++++++++++++++++++++++++++++++++++++++++++------ 1 file changed, 52 insertions(+), 6 deletions(-) (limited to 'libxtables') diff --git a/libxtables/xtables.c b/libxtables/xtables.c index 479dbae0..e3e444ac 100644 --- a/libxtables/xtables.c +++ b/libxtables/xtables.c @@ -2490,16 +2490,39 @@ void xt_xlate_free(struct xt_xlate *xl) free(xl); } +static bool isbrace(char c) +{ + switch (c) { + case '(': + case ')': + case '{': + case '}': + case '[': + case ']': + return true; + } + return false; +} + static void __xt_xlate_add(struct xt_xlate *xl, enum xt_xlate_type type, - const char *fmt, va_list ap) + bool space, const char *fmt, va_list ap) { struct xt_xlate_buf *buf = &xl->buf[type]; + char tmpbuf[1024] = ""; int len; - len = vsnprintf(buf->data + buf->off, buf->rem, fmt, ap); - if (len < 0 || len >= buf->rem) + len = vsnprintf(tmpbuf, 1024, fmt, ap); + if (len < 0 || len >= buf->rem - 1) xtables_error(RESOURCE_PROBLEM, "OOM"); + if (space && buf->off && + !isspace(buf->data[buf->off - 1]) && + (isalnum(tmpbuf[0]) || isbrace(tmpbuf[0]))) { + buf->data[buf->off] = ' '; + buf->off++; + buf->rem--; + } + sprintf(buf->data + buf->off, "%s", tmpbuf); buf->rem -= len; buf->off += len; } @@ -2509,7 +2532,16 @@ void xt_xlate_rule_add(struct xt_xlate *xl, const char *fmt, ...) va_list ap; va_start(ap, fmt); - __xt_xlate_add(xl, XT_XLATE_RULE, fmt, ap); + __xt_xlate_add(xl, XT_XLATE_RULE, true, fmt, ap); + va_end(ap); +} + +void xt_xlate_rule_add_nospc(struct xt_xlate *xl, const char *fmt, ...) +{ + va_list ap; + + va_start(ap, fmt); + __xt_xlate_add(xl, XT_XLATE_RULE, false, fmt, ap); va_end(ap); } @@ -2518,7 +2550,16 @@ void xt_xlate_set_add(struct xt_xlate *xl, const char *fmt, ...) va_list ap; va_start(ap, fmt); - __xt_xlate_add(xl, XT_XLATE_SET, fmt, ap); + __xt_xlate_add(xl, XT_XLATE_SET, true, fmt, ap); + va_end(ap); +} + +void xt_xlate_set_add_nospc(struct xt_xlate *xl, const char *fmt, ...) +{ + va_list ap; + + va_start(ap, fmt); + __xt_xlate_add(xl, XT_XLATE_SET, false, fmt, ap); va_end(ap); } @@ -2545,7 +2586,12 @@ uint8_t xt_xlate_get_family(struct xt_xlate *xl) const char *xt_xlate_get(struct xt_xlate *xl) { - return xl->buf[XT_XLATE_RULE].data; + struct xt_xlate_buf *buf = &xl->buf[XT_XLATE_RULE]; + + while (buf->off && isspace(buf->data[buf->off - 1])) + buf->data[--buf->off] = '\0'; + + return buf->data; } const char *xt_xlate_set_get(struct xt_xlate *xl) -- cgit v1.2.3