Extend tor_sscanf so it can replace sscanf in rephist.c (d4285f03) · Commits · The Tor Project / Core / Tor

changes/bug4195

0 → 100644

+6 −0

Original line number	Diff line number	Diff line
		o Minor features:
		- Enhance our internal sscanf replacement so that we can eliminate
		the last remaining uses of the system sscanf. (Though those uses
		of sscanf were safe, sscanf itself is generally error prone, so
		we want to eliminate when we can.) Fixes ticket 4195 and Coverity
		CID 448.

src/common/util.c

+142 −9

Original line number	Diff line number	Diff line
		@@ -2694,9 +2694,9 @@ digit_to_num(char d)
		* success, store the result in <b>out</b>, advance bufp to the next
		* character, and return 0. On failure, return -1. */
		static int
		scan_unsigned(const char *bufp, unsigned out, int width, int base)
		scan_unsigned(const char *bufp, unsigned long out, int width, int base)
		{
		unsigned result = 0;
		unsigned long result = 0;
		int scanned_so_far = 0;
		const int hex = base==16;
		tor_assert(base == 10 \|\| base == 16);
		@@ -2708,8 +2708,8 @@ scan_unsigned(const char *bufp, unsigned out, int width, int base)
		while (bufp && (hex?TOR_ISXDIGIT(bufp):TOR_ISDIGIT(**bufp))
		&& scanned_so_far < width) {
		int digit = hex?hex_decode_digit((bufp)++):digit_to_num((bufp)++);
		unsigned new_result = result * base + digit;
		if (new_result > UINT32_MAX \|\| new_result < result)
		unsigned long new_result = result * base + digit;
		if (new_result < result)
		return -1; /* over/underflow. */
		result = new_result;
		++scanned_so_far;
		@@ -2722,6 +2722,89 @@ scan_unsigned(const char *bufp, unsigned out, int width, int base)
		return 0;
		}

		/** Helper: Read an signed int from *<b>bufp</b> of up to <b>width</b>
		* characters. (Handle arbitrary width if <b>width</b> is less than 0.) On
		* success, store the result in <b>out</b>, advance bufp to the next
		* character, and return 0. On failure, return -1. */
		static int
		scan_signed(const char *bufp, long out, int width)
		{
		int neg = 0;
		unsigned long result = 0;

		if (!bufp \|\| !*bufp \|\| !out)
		return -1;
		if (width<0)
		width=MAX_SCANF_WIDTH;

		if (**bufp == '-') {
		neg = 1;
		++*bufp;
		--width;
		}

		if (scan_unsigned(bufp, &result, width, 10) < 0)
		return -1;

		if (neg) {
		if (result > ((unsigned long)LONG_MAX) + 1)
		return -1; /* Underflow */
		*out = -(long)result;
		} else {
		if (result > LONG_MAX)
		return -1; /* Overflow */
		*out = (long)result;
		}

		return 0;
		}

		/** Helper: Read a decimal-formatted double from *<b>bufp</b> of up to
		* <b>width</b> characters. (Handle arbitrary width if <b>width</b> is less
		* than 0.) On success, store the result in <b>out</b>, advance bufp to the
		* next character, and return 0. On failure, return -1. */
		static int
		scan_double(const char *bufp, double out, int width)
		{
		int neg = 0;
		double result = 0;
		int scanned_so_far = 0;

		if (!bufp \|\| !*bufp \|\| !out)
		return -1;
		if (width<0)
		width=MAX_SCANF_WIDTH;

		if (**bufp == '-') {
		neg = 1;
		++*bufp;
		}

		while (bufp && TOR_ISDIGIT(bufp) && scanned_so_far < width) {
		const int digit = digit_to_num((bufp)++);
		result = result * 10 + digit;
		++scanned_so_far;
		}
		if (**bufp == '.') {
		double fracval = 0, denominator = 1;
		++*bufp;
		++scanned_so_far;
		while (bufp && TOR_ISDIGIT(bufp) && scanned_so_far < width) {
		const int digit = digit_to_num((bufp)++);
		fracval = fracval * 10 + digit;
		denominator *= 10;
		++scanned_so_far;
		}
		result += fracval / denominator;
		}

		if (!scanned_so_far) /* No actual digits scanned */
		return -1;

		*out = neg ? -result : result;
		return 0;
		}

		/** Helper: copy up to <b>width</b> non-space characters from <b>bufp</b> to
		* <b>out</b>. Make sure <b>out</b> is nul-terminated. Advance <b>bufp</b>
		* to the next non-space character or the EOS. */
		@@ -2758,6 +2841,7 @@ tor_vsscanf(const char buf, const char pattern, va_list ap)
		}
		} else {
		int width = -1;
		int longmod = 0;
		++pattern;
		if (TOR_ISDIGIT(*pattern)) {
		width = digit_to_num(*pattern++);
		@@ -2770,17 +2854,57 @@ tor_vsscanf(const char buf, const char pattern, va_list ap)
		if (!width) /* No zero-width things. */
		return -1;
		}
		if (*pattern == 'l') {
		longmod = 1;
		++pattern;
		}
		if (pattern == 'u' \|\| pattern == 'x') {
		unsigned u = va_arg(ap, unsigned );
		unsigned long u;
		const int base = (*pattern == 'u') ? 10 : 16;
		if (!*buf)
		return n_matched;
		if (scan_unsigned(&buf, u, width, base)<0)
		if (scan_unsigned(&buf, &u, width, base)<0)
		return n_matched;
		if (longmod) {
		unsigned long out = va_arg(ap, unsigned long );
		*out = u;
		} else {
		unsigned out = va_arg(ap, unsigned );
		if (u > UINT_MAX)
		return n_matched;
		*out = u;
		}
		++pattern;
		++n_matched;
		} else if (*pattern == 'f') {
		double d = va_arg(ap, double );
		if (!longmod)
		return -1; /* float not supported */
		if (!*buf)
		return n_matched;
		if (scan_double(&buf, d, width)<0)
		return n_matched;
		++pattern;
		++n_matched;
		} else if (*pattern == 'd') {
		long lng=0;
		if (scan_signed(&buf, &lng, width)<0)
		return n_matched;
		if (longmod) {
		long out = va_arg(ap, long );
		*out = lng;
		} else {
		int out = va_arg(ap, int );
		if (lng < INT_MIN \|\| lng > INT_MAX)
		return n_matched;
		*out = (int)lng;
		}
		++pattern;
		++n_matched;
		} else if (*pattern == 's') {
		char s = va_arg(ap, char );
		if (longmod)
		return -1;
		if (width < 0)
		return -1;
		if (scan_string(&buf, s, width)<0)
		@@ -2789,6 +2913,8 @@ tor_vsscanf(const char buf, const char pattern, va_list ap)
		++n_matched;
		} else if (*pattern == 'c') {
		char ch = va_arg(ap, char );
		if (longmod)
		return -1;
		if (width != -1)
		return -1;
		if (!*buf)
		@@ -2799,6 +2925,8 @@ tor_vsscanf(const char buf, const char pattern, va_list ap)
		} else if (*pattern == '%') {
		if (*buf != '%')
		return n_matched;
		if (longmod)
		return -1;
		++buf;
		++pattern;
		} else {
		@@ -2812,9 +2940,14 @@ tor_vsscanf(const char buf, const char pattern, va_list ap)

		/** Minimal sscanf replacement: parse <b>buf</b> according to <b>pattern</b>
		* and store the results in the corresponding argument fields. Differs from
		* sscanf in that it: Only handles %u, %x, %c and %Ns. Does not handle
		* arbitrarily long widths. %u and %x do not consume any space. Is
		* locale-independent. Returns -1 on malformed patterns.
		* sscanf in that:
		* <ul><li>It only handles %u, %lu, %x, %lx, %<NUM>s, %d, %ld, %lf, and %c.
		* <li>It only handles decimal inputs for %lf. (12.3, not 1.23e1)
		* <li>It does not handle arbitrarily long widths.
		* <li>Numbers do not consume any space characters.
		* <li>It is locale-independent.
		* <li>%u and %x do not consume any space.
		* <li>It returns -1 on malformed patterns.</ul>
		*
		* (As with other locale-independent functions, we need this to parse data that
		* is in ASCII without worrying that the C library's locale-handling will make

src/or/rephist.c

+3 −3

Original line number	Diff line number	Diff line
		@@ -1136,7 +1136,7 @@ rep_hist_load_mtbf_data(time_t now)
		wfu_timebuf[0] = '\0';

		if (format == 1) {
		n = sscanf(line, "%40s %ld %lf S=%10s %8s",
		n = tor_sscanf(line, "%40s %ld %lf S=%10s %8s",
		hexbuf, &wrl, &trw, mtbf_timebuf, mtbf_timebuf+11);
		if (n != 3 && n != 5) {
		log_warn(LD_HIST, "Couldn't scan line %s", escaped(line));
		@@ -1153,7 +1153,7 @@ rep_hist_load_mtbf_data(time_t now)
		wfu_idx = find_next_with(lines, i+1, "+WFU ");
		if (mtbf_idx >= 0) {
		const char *mtbfline = smartlist_get(lines, mtbf_idx);
		n = sscanf(mtbfline, "+MTBF %lu %lf S=%10s %8s",
		n = tor_sscanf(mtbfline, "+MTBF %lu %lf S=%10s %8s",
		&wrl, &trw, mtbf_timebuf, mtbf_timebuf+11);
		if (n == 2 \|\| n == 4) {
		have_mtbf = 1;
		@@ -1164,7 +1164,7 @@ rep_hist_load_mtbf_data(time_t now)
		}
		if (wfu_idx >= 0) {
		const char *wfuline = smartlist_get(lines, wfu_idx);
		n = sscanf(wfuline, "+WFU %lu %lu S=%10s %8s",
		n = tor_sscanf(wfuline, "+WFU %lu %lu S=%10s %8s",
		&wt_uptime, &total_wt_time,
		wfu_timebuf, wfu_timebuf+11);
		if (n == 2 \|\| n == 4) {

src/test/test_util.c

+75 −0

Original line number	Diff line number	Diff line
		@@ -1461,12 +1461,28 @@ test_util_control_formats(void)
		tor_free(out);
		}

		#define test_feq(value1,value2) do { \
		double v1 = (value1), v2=(value2); \
		double tf_diff = v1-v2; \
		double tf_tolerance = ((v1+v2)/2.0)/1e8; \
		if (tf_diff<0) tf_diff=-tf_diff; \
		if (tf_tolerance<0) tf_tolerance=-tf_tolerance; \
		if (tf_diff<tf_tolerance) { \
		TT_BLATHER(("%s ~~ %s: %f ~~ %f",#value1,#value2,v1,v2)); \
		} else { \
		TT_FAIL(("%s ~~ %s: %f != %f",#value1,#value2,v1,v2)); \
		} \
		} while(0)

		static void
		test_util_sscanf(void)
		{
		unsigned u1, u2, u3;
		char s1[20], s2[10], s3[10], ch;
		int r;
		long lng1,lng2;
		int int1, int2;
		double d1,d2,d3,d4;

		/* Simple tests (malformed patterns, literal matching, ...) */
		test_eq(-1, tor_sscanf("123", "%i", &r)); /* %i is not supported */
		@@ -1595,6 +1611,65 @@ test_util_sscanf(void)
		test_eq(4, tor_sscanf("1.2.3 foobar", "%u.%u.%u%c", &u1, &u2, &u3, &ch));
		test_eq(' ', ch);

		r = tor_sscanf("12345 -67890 -1", "%d %ld %d", &int1, &lng1, &int2);
		test_eq(r,3);
		test_eq(int1, 12345);
		test_eq(lng1, -67890);
		test_eq(int2, -1);

		#if SIZEOF_INT == 4
		r = tor_sscanf("-2147483648. 2147483647.", "%d. %d.", &int1, &int2);
		test_eq(r,2);
		test_eq(int1, -2147483648);
		test_eq(int2, 2147483647);

		r = tor_sscanf("-2147483679.", "%d.", &int1);
		test_eq(r,0);

		r = tor_sscanf("2147483678.", "%d.", &int1);
		test_eq(r,0);
		#elif SIZEOF_INT == 8
		r = tor_sscanf("-9223372036854775808. 9223372036854775807.",
		"%d. %d.", &int1, &int2);
		test_eq(r,2);
		test_eq(int1, -9223372036854775808);
		test_eq(int2, 9223372036854775807);

		r = tor_sscanf("-9223372036854775809.", "%d.", &int1);
		test_eq(r,0);

		r = tor_sscanf("9223372036854775808.", "%d.", &int1);
		test_eq(r,0);
		#endif

		#if SIZEOF_LONG == 4
		r = tor_sscanf("-2147483648. 2147483647.", "%ld. %ld.", &lng1, &lng2)
		test_eq(r,2);
		test_eq(lng1, -2147483647 - 1);
		test_eq(lng2, 2147483647);
		#elif SIZEOF_LONG == 8
		r = tor_sscanf("-9223372036854775808. 9223372036854775807.",
		"%ld. %ld.", &lng1, &lng2);
		test_eq(r,2);
		test_eq(lng1, -9223372036854775807L - 1);
		test_eq(lng2, 9223372036854775807L);

		r = tor_sscanf("-9223372036854775808. 9223372036854775808.",
		"%ld. %ld.", &lng1, &lng2);
		test_eq(r,1);
		r = tor_sscanf("-9223372036854775809. 9223372036854775808.",
		"%ld. %ld.", &lng1, &lng2);
		test_eq(r,0);
		#endif

		r = tor_sscanf("123.456 .000007 -900123123.2000787 00003.2",
		"%lf %lf %lf %lf", &d1,&d2,&d3,&d4);
		test_eq(r,4);
		test_feq(d1, 123.456);
		test_feq(d2, .000007);
		test_feq(d3, -900123123.2000787);
		test_feq(d4, 3.2);

		done:
		;
		}