Rewrite man5/config.pod and related conf code cleanup

The manpage is basically rewritten.  Use consistent name/value
terminology. Use consistent phraseology to refer to section pointers
and lists of section pointers. Add more cross-references.

Also found a bunch of trivial style things in conf_api.c while
investigating how config works.

Reviewed-by: Nicola Tuveri <nic.tuv@gmail.com>
Reviewed-by: Tomas Mraz <tmraz@fedoraproject.org>
(Merged from https://github.com/openssl/openssl/pull/11431)

1 files changed, 28 insertions, 39 deletions

diff --git a/crypto/conf/conf_api.c b/crypto/conf/conf_api.c
index 4248de60e1..4c7349a305 100644
--- a/crypto/conf/conf_api.c
+++ b/crypto/conf/conf_api.c
@@ -19,30 +19,26 @@
 static void value_free_hash(const CONF_VALUE *a, LHASH_OF(CONF_VALUE) *conf);
 static void value_free_stack_doall(CONF_VALUE *a);
 
-/* Up until OpenSSL 0.9.5a, this was get_section */
 CONF_VALUE *_CONF_get_section(const CONF *conf, const char *section)
 {
-    CONF_VALUE *v, vv;
+    CONF_VALUE vv;
 
-    if ((conf == NULL) || (section == NULL))
+    if (conf == NULL || section == NULL)
         return NULL;
     vv.name = NULL;
     vv.section = (char *)section;
-    v = lh_CONF_VALUE_retrieve(conf->data, &vv);
-    return v;
+    return lh_CONF_VALUE_retrieve(conf->data, &vv);
 }
 
-/* Up until OpenSSL 0.9.5a, this was CONF_get_section */
 STACK_OF(CONF_VALUE) *_CONF_get_section_values(const CONF *conf,
                                                const char *section)
 {
     CONF_VALUE *v;
 
     v = _CONF_get_section(conf, section);
-    if (v != NULL)
-        return ((STACK_OF(CONF_VALUE) *)v->value);
-    else
+    if (v == NULL)
         return NULL;
+    return ((STACK_OF(CONF_VALUE) *)v->value);
 }
 
 int _CONF_add_string(CONF *conf, CONF_VALUE *section, CONF_VALUE *value)
@@ -53,9 +49,8 @@ int _CONF_add_string(CONF *conf, CONF_VALUE *section, CONF_VALUE *value)
     ts = (STACK_OF(CONF_VALUE) *)section->value;
 
     value->section = section->section;
-    if (!sk_CONF_VALUE_push(ts, value)) {
+    if (!sk_CONF_VALUE_push(ts, value))
         return 0;
-    }
 
     v = lh_CONF_VALUE_insert(conf->data, value);
     if (v != NULL) {
@@ -75,28 +70,26 @@ char *_CONF_get_string(const CONF *conf, const char *section,
 
     if (name == NULL)
         return NULL;
-    if (conf != NULL) {
-        if (section != NULL) {
-            vv.name = (char *)name;
-            vv.section = (char *)section;
-            v = lh_CONF_VALUE_retrieve(conf->data, &vv);
-            if (v != NULL)
-                return v->value;
-            if (strcmp(section, "ENV") == 0) {
-                p = ossl_safe_getenv(name);
-                if (p != NULL)
-                    return p;
-            }
-        }
-        vv.section = "default";
+    if (conf == NULL)
+        return ossl_safe_getenv(name);
+    if (section != NULL) {
         vv.name = (char *)name;
+        vv.section = (char *)section;
         v = lh_CONF_VALUE_retrieve(conf->data, &vv);
         if (v != NULL)
             return v->value;
-        else
-            return NULL;
-    } else
-        return ossl_safe_getenv(name);
+        if (strcmp(section, "ENV") == 0) {
+            p = ossl_safe_getenv(name);
+            if (p != NULL)
+                return p;
+        }
+    }
+    vv.section = "default";
+    vv.name = (char *)name;
+    v = lh_CONF_VALUE_retrieve(conf->data, &vv);
+    if (v == NULL)
+        return NULL;
+    return v->value;
 }
 
 static unsigned long conf_value_hash(const CONF_VALUE *v)
@@ -110,24 +103,21 @@ static int conf_value_cmp(const CONF_VALUE *a, const CONF_VALUE *b)
 
     if (a->section != b->section) {
         i = strcmp(a->section, b->section);
-        if (i)
+        if (i != 0)
             return i;
     }
 
-    if ((a->name != NULL) && (b->name != NULL)) {
-        i = strcmp(a->name, b->name);
-        return i;
-    } else if (a->name == b->name)
+    if (a->name != NULL && b->name != NULL)
+        return strcmp(a->name, b->name);
+    if (a->name == b->name)
         return 0;
-    else
-        return ((a->name == NULL) ? -1 : 1);
+    return (a->name == NULL) ? -1 : 1;
 }
 
 int _CONF_new_data(CONF *conf)
 {
-    if (conf == NULL) {
+    if (conf == NULL)
         return 0;
-    }
     if (conf->data == NULL) {
         conf->data = lh_CONF_VALUE_new(conf_value_hash, conf_value_cmp);
         if (conf->data == NULL)
@@ -185,7 +175,6 @@ static void value_free_stack_doall(CONF_VALUE *a)
     OPENSSL_free(a);
 }
 
-/* Up until OpenSSL 0.9.5a, this was new_section */
 CONF_VALUE *_CONF_new_section(CONF *conf, const char *section)
 {
     STACK_OF(CONF_VALUE) *sk = NULL;