feat(lnm): move request data to separate buffer if read buffer changes

lnm/include/lnm/http/req.h

@@ -13,24 +13,39 @@
 #define LNM_HTTP_MAX_REQ_HEADERS 32
 #define LNM_HTTP_MAX_REGEX_GROUPS 4
 
+typedef struct lnm_http_req_header {
+  struct {
+    size_t o;
+    size_t len;
+  } name;
+  struct {
+    size_t o;
+    size_t len;
+  } value;
+} lnm_http_req_header;
+
 /**
  * Represents the parsed HTTP request
  */
 typedef struct lnm_http_req {
-  size_t len;
+  struct {
+    char *s;
+    size_t len;
+    bool owned;
+  } buf;
   int minor_version;
   lnm_http_method method;
   struct {
-    const char *s;
+    size_t o;
     size_t len;
     regmatch_t groups[LNM_HTTP_MAX_REGEX_GROUPS];
   } path;
   struct {
-    const char *s;
+    size_t o;
     size_t len;
   } query;
   struct {
-    struct phr_header arr[LNM_HTTP_MAX_REQ_HEADERS];
+    lnm_http_req_header arr[LNM_HTTP_MAX_REQ_HEADERS];
     size_t len;
   } headers;
   struct {
@@ -68,6 +83,9 @@ void lnm_http_req_reset(lnm_http_req *req);
 /**
  * Retrieve a specific header from the request.
  *
+ * Pointers retrieved from this function should never be used between step
+ * functions; simply request the header again if you need to.
+ *
  * @param out where to write pointer to header value
  * @param out_len where to store length of out value
  * @param req request to look for header in
@@ -79,6 +97,9 @@ lnm_err lnm_http_req_header_get(const char **out, size_t *out_len,
 /**
  * Retrieve a specific header from the request by specifying its name.
  *
+ * Pointers retrieved from this function should never be used between step
+ * functions; simply request the header again if you need to.
+ *
  * @param out where to write pointer to header value
  * @param out_len where to store length of out value
  * @param req request to look for header in

lnm/src/http/lnm_http_loop_process.c

@@ -25,12 +25,12 @@ void lnm_http_loop_process_parse_req(lnm_http_conn *conn) {
 
   switch (res) {
   case lnm_http_parse_err_ok:
-    conn->r.read += ctx->req.len;
+    conn->r.read += ctx->req.buf.len;
     ctx->state = lnm_http_loop_state_route;
 
     lnm_linfo(section, "%s %.*s HTTP/1.%i",
               lnm_http_method_names[ctx->req.method], (int)ctx->req.path.len,
-              ctx->req.path.s, ctx->req.minor_version);
+              ctx->req.buf.s + ctx->req.path.o, ctx->req.minor_version);
     break;
   case lnm_http_parse_err_incomplete:
     // If the request is already the size of the read buffer, we close the
@@ -70,12 +70,12 @@ void lnm_http_loop_process_route(lnm_http_conn *conn) {
 
     switch (route->type) {
     case lnm_http_route_type_literal:
-      matched_path =
-          strncmp(route->route.s, ctx->req.path.s, ctx->req.path.len) == 0;
+      matched_path = strncmp(route->route.s, ctx->req.buf.s + ctx->req.path.o,
+                             ctx->req.path.len) == 0;
       break;
     case lnm_http_route_type_regex:
       matched_path =
-          regexec(route->route.regex, ctx->req.path.s,
+          regexec(route->route.regex, ctx->req.buf.s + ctx->req.path.o,
                   LNM_HTTP_MAX_REGEX_GROUPS, ctx->req.path.groups, 0) == 0;
       break;
     }
@@ -345,7 +345,7 @@ lnm_loop_state state_map[] = {
 };
 
 void lnm_http_loop_process(lnm_http_conn *conn) {
-  const lnm_http_loop_ctx *ctx = conn->ctx;
+  lnm_http_loop_ctx *ctx = conn->ctx;
 
   lnm_http_loop_state http_loop_state;
   lnm_loop_state loop_state = conn->state;
@@ -366,4 +366,26 @@ void lnm_http_loop_process(lnm_http_conn *conn) {
 
   // Check required to prevent overwriting manually set event loop state
   conn->state = conn->state == loop_state ? state_map[ctx->state] : conn->state;
+
+  // We move the request to a dedicated buffer if the read buffer needs to be
+  // reused
+  if ((conn->state == lnm_loop_state_req) && (conn->state == loop_state) &&
+      (!ctx->req.buf.owned) && (ctx->req.buf.len > 0)) {
+    char *buf = malloc(ctx->req.buf.len);
+
+    if (buf == NULL) {
+      lnm_lerror(section,
+                 "Failed to allocate request buffer; closing connection %i",
+                 conn->fd);
+
+      conn->state = lnm_loop_state_end;
+    } else {
+      memcpy(buf, ctx->req.buf.s, ctx->req.buf.len);
+      ctx->req.buf.s = buf;
+      ctx->req.buf.owned = true;
+
+      lnm_ldebug(section, "Allocated request buffer for connection %i",
+                 conn->fd);
+    }
+  }
 }

lnm/src/http/lnm_http_req.c

@@ -11,15 +11,15 @@ lnm_http_parse_err lnm_http_req_parse(lnm_http_req *req, char *buf,
   const char *method;
   char *path;
   size_t method_len, path_len;
-
-  req->headers.len = LNM_HTTP_MAX_REQ_HEADERS;
+  size_t num_headers = LNM_HTTP_MAX_REQ_HEADERS;
+  struct phr_header headers[LNM_HTTP_MAX_REQ_HEADERS];
 
   int req_len = phr_parse_request(
       buf, len, &method, &method_len, (const char **)&path, &path_len,
-      &req->minor_version, req->headers.arr, &req->headers.len, req->len);
+      &req->minor_version, headers, &num_headers, req->buf.len);
 
   if (req_len == -1) {
-    req->len = len;
+    req->buf.len = len;
 
     return lnm_http_parse_err_invalid;
   } else if (req_len == -2) {
@@ -45,7 +45,7 @@ lnm_http_parse_err lnm_http_req_parse(lnm_http_req *req, char *buf,
 
   // Only store query if the path doesn't simply end with a question mark
   if ((question_mark != NULL) && (path_len - (question_mark + 1 - path) > 0)) {
-    req->query.s = question_mark + 1;
+    req->query.o = question_mark + 1 - buf;
     req->query.len = path_len - (question_mark + 1 - path);
 
     path_len = question_mark - path;
@@ -56,9 +56,22 @@ lnm_http_parse_err lnm_http_req_parse(lnm_http_req *req, char *buf,
     path[path_len] = '\0';
   }
 
+  // Also migrate headers to offset-based
+  for (size_t i = 0; i < num_headers; i++) {
+    req->headers.arr[i].name.o = headers[i].name - buf;
+    req->headers.arr[i].name.len = headers[i].name_len;
+    req->headers.arr[i].value.o = headers[i].value - buf;
+    req->headers.arr[i].value.len = headers[i].value_len;
+  }
+
+  req->headers.len = num_headers;
+
   req->path.len = path_len;
-  req->path.s = path;
-  req->len = req_len;
+  req->path.o = path - buf;
+
+  req->buf.len = req_len;
+  req->buf.s = buf;
+  req->buf.owned = false;
 
   return lnm_http_parse_err_ok;
 }
@@ -68,6 +81,10 @@ void lnm_http_req_reset(lnm_http_req *req) {
     free(req->body.buf);
   }
 
+  if (req->buf.owned) {
+    free(req->buf.s);
+  }
+
   memset(req, 0, sizeof(lnm_http_req));
 }
 
@@ -82,11 +99,12 @@ lnm_err lnm_http_req_header_get_s(const char **out, size_t *out_len,
   size_t name_len = strlen(name);
 
   for (size_t i = 0; i < req->headers.len; i++) {
-    const struct phr_header *header = &req->headers.arr[i];
+    const lnm_http_req_header *header = &req->headers.arr[i];
 
-    if (lnm_strnieq(header->name, header->name_len, name, name_len)) {
-      *out = header->value;
-      *out_len = header->value_len;
+    if (lnm_strnieq(req->buf.s + header->name.o, header->name.len, name,
+                    name_len)) {
+      *out = req->buf.s + header->value.o;
+      *out_len = header->value.len;
 
       return lnm_err_ok;
     }

src/lander/lander_delete.c

@@ -8,7 +8,8 @@ lnm_http_step_err lander_remove_entry(lnm_http_conn *conn) {
   lnm_http_loop_gctx *gctx = ctx->g;
   lander_gctx *c_gctx = gctx->c;
 
-  const char *key_s = &ctx->req.path.s[ctx->req.path.groups[1].rm_so];
+  const char *key_s =
+      &ctx->req.buf.s[ctx->req.path.o + ctx->req.path.groups[1].rm_so];
   int key_len = ctx->req.path.groups[1].rm_eo - ctx->req.path.groups[1].rm_so;
 
   lsm_str *key;

src/lander/lander_get.c

@@ -118,7 +118,8 @@ lnm_http_step_err lander_get_entry(lnm_http_conn *conn) {
   lnm_http_loop_gctx *gctx = ctx->g;
   lander_gctx *c_gctx = gctx->c;
 
-  const char *key_s = &ctx->req.path.s[ctx->req.path.groups[1].rm_so];
+  const char *key_s =
+      &ctx->req.buf.s[ctx->req.path.o + ctx->req.path.groups[1].rm_so];
   int key_len = ctx->req.path.groups[1].rm_eo - ctx->req.path.groups[1].rm_so;
 
   lsm_str *key;

src/lander/lander_post.c

@@ -38,7 +38,8 @@ bool lander_insert_entry(lnm_http_loop_ctx *ctx) {
     randomize_key(key_s, key_len);
     lsm_str_init(&key, key_s);
   } else {
-    const char *key_s = &ctx->req.path.s[ctx->req.path.groups[2].rm_so];
+    const char *key_s =
+        &ctx->req.buf.s[ctx->req.path.o + ctx->req.path.groups[2].rm_so];
     key_len = ctx->req.path.groups[2].rm_eo - ctx->req.path.groups[2].rm_so;
 
     lsm_str_init_copy_n(&key, key_s, key_len);