GopherProxy

	Refactor range-parsing into a separate function - quark - quark web server
	git clone git://git.suckless.org/quark
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	---
	commit 26c593ade1949608a4d5a8a1b70eb6b11d8dc316
	parent 5a7994bc61ce868521fc996e46006b61d07d23c4
	Author: Laslo Hunhold <[email protected]>
	Date: Tue, 4 Aug 2020 16:31:08 +0200

	Refactor range-parsing into a separate function

	The method http_send_response() is already long enough and this
	separation of concerns both helps shorten it a bit, improves
	readability and reduces the chance of programming errors.

	Signed-off-by: Laslo Hunhold <[email protected]>

	Diffstat:
	M http.c \| 203 +++++++++++++++++------------…

	1 file changed, 110 insertions(+), 93 deletions(-)
	---
	diff --git a/http.c b/http.c
	@@ -342,6 +342,109 @@ squash:
	return 0;
	}

	+static enum status
	+parse_range(char s, off_t size, off_t lower, off_t *upper)
	+{
	+ char p, q;
	+ const char *err;
	+
	+ /* default to the complete range */
	+ *lower = 0;
	+ *upper = size - 1;
	+
	+ /* done if no range-string is given */
	+ if (s == NULL \|\| *s == '\0') {
	+ return 0;
	+ }
	+
	+ /* skip opening statement */
	+ if (strncmp(s, "bytes=", sizeof("bytes=") - 1)) {
	+ return S_BAD_REQUEST;
	+ }
	+ p = s + (sizeof("bytes=") - 1);
	+
	+ /* find hyphen and replace with \0 */
	+ if (!(q = strchr(p, '-'))) {
	+ return S_BAD_REQUEST;
	+ }
	+ *(q++) = '\0';
	+
	+ /*
	+ * byte-range=first\0last...
	+ * ^ ^
	+ * \| \|
	+ * p q
	+ */
	+
	+ /*
	+ * make sure we only have a single range, and not a comma
	+ * separated list, which we will refuse to accept out of spite
	+ * towards this horrible part of the spec
	+ */
	+ if (strchr(q, ',')) {
	+ return S_RANGE_NOT_SATISFIABLE;
	+ }
	+
	+ if (p[0] != '\0') {
	+ /*
	+ * Range has format "first-last" or "first-",
	+ * i.e. return bytes 'first' to 'last' (or the
	+ * last byte if 'last' is not given),
	+ * inclusively, and byte-numbering beginning at 0
	+ */
	+ *lower = strtonum(p, 0, LLONG_MAX, &err);
	+ if (!err) {
	+ if (q[0] != '\0') {
	+ *upper = strtonum(q, 0, LLONG_MAX, &err);
	+ } else {
	+ *upper = size - 1;
	+ }
	+ }
	+ if (err) {
	+ /* one of the strtonum()'s failed */
	+ return S_BAD_REQUEST;
	+ }
	+
	+ /* check ranges */
	+ if (lower > upper \|\| *lower >= size) {
	+ return S_RANGE_NOT_SATISFIABLE;
	+ }
	+
	+ /* adjust upper limit to be at most the last byte */
	+ upper = MIN(upper, size - 1);
	+ } else {
	+ /*
	+ * Range has format "-num", i.e. return the 'num'
	+ * last bytes
	+ */
	+
	+ /*
	+ * use upper as a temporary storage for 'num',
	+ * as we know 'upper' is size - 1
	+ */
	+ *upper = strtonum(q, 0, LLONG_MAX, &err);
	+ if (err) {
	+ return S_BAD_REQUEST;
	+ }
	+
	+ /* determine lower */
	+ if (*upper > size) {
	+ /* more bytes requested than we have */
	+ *lower = 0;
	+ } else {
	+ lower = size - upper;
	+ }
	+
	+ /* set upper to the correct value */
	+ *upper = size - 1;
	+ }
	+
	+ /* reset \0 to the hyphen */
	+ *(q - 1) = '-';
	+
	+ return 0;
	+}
	+
	#undef RELPATH
	#define RELPATH(x) ((!*(x) \|\| !strcmp(x, "/")) ? "." : ((x) + 1))

	@@ -355,8 +458,8 @@ http_send_response(int fd, struct request *r)
	off_t lower, upper;
	int hasport, ipv6host;
	static char realtarget[PATH_MAX], tmptarget[PATH_MAX], t[TIMESTAMP_LEN…
	- char p, q, *mime;
	- const char vhostmatch, targethost, *err;
	+ char p, mime;
	+ const char vhostmatch, targethost;

	/* make a working copy of the target */
	memcpy(realtarget, r->target, sizeof(realtarget));
	@@ -546,96 +649,8 @@ http_send_response(int fd, struct request *r)
	}

	/* range */
	- lower = 0;
	- upper = st.st_size - 1;
	- if (r->field[REQ_RANGE][0]) {
	- /* parse field */
	- p = r->field[REQ_RANGE];
	- err = NULL;
	-
	- if (strncmp(p, "bytes=", sizeof("bytes=") - 1)) {
	- return http_send_status(fd, S_BAD_REQUEST);
	- }
	- p += sizeof("bytes=") - 1;
	-
	- if (!(q = strchr(p, '-'))) {
	- return http_send_status(fd, S_BAD_REQUEST);
	- }
	- *(q++) = '\0';
	-
	- /*
	- * byte-range=first\0last...
	- * ^ ^
	- * \| \|
	- * p q
	- */
	-
	- /*
	- * make sure we only have a single range,
	- * and not a comma separated list, which we
	- * will refuse to accept out of spite towards
	- * this horrible part of the spec
	- */
	- if (strchr(q, ',')) {
	- goto not_satisfiable;
	- }
	-
	- if (p[0] != '\0') {
	- /*
	- * Range has format "first-last" or "first-",
	- * i.e. return bytes 'first' to 'last' (or the
	- * last byte if 'last' is not given),
	- * inclusively, and byte-numbering beginning at 0
	- */
	- lower = strtonum(p, 0, LLONG_MAX, &err);
	- if (!err) {
	- if (q[0] != '\0') {
	- upper = strtonum(q, 0, LLONG_MAX,
	- &err);
	- } else {
	- upper = st.st_size - 1;
	- }
	- }
	- if (err) {
	- /* one of the strtonum()'s failed */
	- return http_send_status(fd, S_BAD_REQUEST);
	- }
	-
	- /* check ranges */
	- if (lower > upper \|\| lower >= st.st_size) {
	- goto not_satisfiable;
	- }
	-
	- /* adjust upper limit to be at most the last byte */
	- upper = MIN(upper, st.st_size - 1);
	- } else {
	- /*
	- * Range has format "-num", i.e. return the 'num'
	- * last bytes
	- */
	-
	- /*
	- * use upper as a temporary storage for 'num',
	- * as we know 'upper' is st.st_size - 1
	- */
	- upper = strtonum(q, 0, LLONG_MAX, &err);
	- if (err) {
	- return http_send_status(fd, S_BAD_REQUEST);
	- }
	-
	- /* determine lower */
	- if (upper > st.st_size) {
	- /* more bytes requested than we have */
	- lower = 0;
	- } else {
	- lower = st.st_size - upper;
	- }
	-
	- /* set upper to the correct value */
	- upper = st.st_size - 1;
	- }
	- goto satisfiable;
	-not_satisfiable:
	+ switch (parse_range(r->field[REQ_RANGE], st.st_size, &lower, &upper)) {
	+ case S_RANGE_NOT_SATISFIABLE:
	if (dprintf(fd,
	"HTTP/1.1 %d %s\r\n"
	"Date: %s\r\n"
	@@ -649,7 +664,9 @@ not_satisfiable:
	return S_REQUEST_TIMEOUT;
	}
	return S_RANGE_NOT_SATISFIABLE;
	-satisfiable:
	+ case S_BAD_REQUEST:
	+ return http_send_status(fd, S_BAD_REQUEST);
	+ default:
	;
	}