Rewrite parse_path_info() to be four lines shorter, simplify ownership

of allocated strings, do not write to the input string, and improve
diagnostic output.

The confusing error message "invalid arch" as a reaction to mistyping
the release name was noticed by tb@, who likes the new code and message.

diff --git a/cgi.c b/cgi.c
index afb38f1d8c5c4d71f554713f012fb5ad4fe6d29f..ccda87a704f9b0db0b4e245dfb265c5461b2646e 100644 (file)
--- a/cgi.c
+++ b/cgi.c
@@ -1,4 +1,4 @@
-/*     $Id: cgi.c,v 1.160 2018/10/02 19:41:23 schwarze Exp $ */
+/*     $Id: cgi.c,v 1.161 2018/10/19 21:10:56 schwarze Exp $ */
 /*
  * Copyright (c) 2011, 2012 Kristaps Dzonsons <kristaps@bsd.lv>
  * Copyright (c) 2014, 2015, 2016, 2017, 2018 Ingo Schwarze <schwarze@usta.de>
@@ -1144,80 +1144,74 @@ main(void)
 }
 
 /*
- * If PATH_INFO is not a file name, translate it to a query.
+ * Translate PATH_INFO to a query.
  */
 static void
 parse_path_info(struct req *req, const char *path)
 {
-       char    *dir[4];
-       int      i;
+       const char      *name, *sec, *end;
 
        req->isquery = 0;
        req->q.equal = 1;
-       req->q.manpath = mandoc_strdup(path);
+       req->q.manpath = NULL;
        req->q.arch = NULL;
 
        /* Mandatory manual page name. */
-       if ((req->q.query = strrchr(req->q.manpath, '/')) == NULL) {
-               req->q.query = req->q.manpath;
-               req->q.manpath = NULL;
-       } else
-               *req->q.query++ = '\0';
+       if ((name = strrchr(path, '/')) == NULL)
+               name = path;
+       else
+               name++;
 
        /* Optional trailing section. */
-       if ((req->q.sec = strrchr(req->q.query, '.')) != NULL) {
-               if(isdigit((unsigned char)req->q.sec[1])) {
-                       *req->q.sec++ = '\0';
-                       req->q.sec = mandoc_strdup(req->q.sec);
-               } else
-                       req->q.sec = NULL;
+       sec = strrchr(name, '.');
+       if (sec != NULL && isdigit((unsigned char)*++sec)) {
+               req->q.query = mandoc_strndup(name, sec - name - 1);
+               req->q.sec = mandoc_strdup(sec);
+       } else {
+               req->q.query = mandoc_strdup(name);
+               req->q.sec = NULL;
        }
 
        /* Handle the case of name[.section] only. */
-       if (req->q.manpath == NULL)
+       if (name == path)
                return;
-       req->q.query = mandoc_strdup(req->q.query);
-
-       /* Split directory components. */
-       dir[i = 0] = req->q.manpath;
-       while ((dir[i + 1] = strchr(dir[i], '/')) != NULL) {
-               if (++i == 3) {
-                       pg_error_badrequest(
-                           "You specified too many directory components.");
-                       exit(EXIT_FAILURE);
-               }
-               *dir[i]++ = '\0';
-       }
 
        /* Optional manpath. */
-       if ((i = validate_manpath(req, req->q.manpath)) == 0)
+       end = strchr(path, '/');
+       req->q.manpath = mandoc_strndup(path, end - path);
+       if (validate_manpath(req, req->q.manpath)) {
+               path = end + 1;
+               if (name == path)
+                       return;
+       } else {
+               free(req->q.manpath);
                req->q.manpath = NULL;
-       else if (dir[1] == NULL)
-               return;
+       }
 
        /* Optional section. */
-       if (strncmp(dir[i], "man", 3) == 0) {
+       if (strncmp(path, "man", 3) == 0) {
+               path += 3;
+               end = strchr(path, '/');
                free(req->q.sec);
-               req->q.sec = mandoc_strdup(dir[i++] + 3);
+               req->q.sec = mandoc_strndup(path, end - path);
+               path = end + 1;
+               if (name == path)
+                       return;
        }
-       if (dir[i] == NULL) {
-               if (req->q.manpath == NULL)
-                       free(dir[0]);
-               return;
+
+       /* Optional architecture. */
+       end = strchr(path, '/');
+       if (end + 1 != name) {
+               pg_error_badrequest(
+                   "You specified too many directory components.");
+               exit(EXIT_FAILURE);
        }
-       if (dir[i + 1] != NULL) {
+       req->q.arch = mandoc_strndup(path, end - path);
+       if (validate_arch(req->q.arch) == 0) {
                pg_error_badrequest(
                    "You specified an invalid directory component.");
                exit(EXIT_FAILURE);
        }
-
-       /* Optional architecture. */
-       if (i) {
-               req->q.arch = mandoc_strdup(dir[i]);
-               if (req->q.manpath == NULL)
-                       free(dir[0]);
-       } else
-               req->q.arch = dir[0];
 }
 
 /*