Perl: disabled unrelated calls from variable handlers.

Variable handlers are not expected to send anything to the client, cannot
sleep or read body, and are not expected to modify the request.  Added
appropriate protection to prevent accidental foot shooting.

src/http/modules/perl/nginx.xs

diff --git a/src/http/modules/perl/nginx.xs b/src/http/modules/perl/nginx.xs
index e9db2f7..67ec0a5 100644
--- a/src/http/modules/perl/nginx.xs
+++ b/src/http/modules/perl/nginx.xs
@@ -110,6 +110,10 @@
 
     ngx_http_perl_set_request(r, ctx);
 
+    if (ctx->variable) {
+        croak("status(): cannot be used in variable handler");
+    }
+
     r->headers_out.status = SvIV(ST(1));
 
     ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
@@ -133,6 +137,10 @@
         croak("send_http_header(): called after error");
     }
 
+    if (ctx->variable) {
+        croak("send_http_header(): cannot be used in variable handler");
+    }
+
     if (r->headers_out.status == 0) {
         r->headers_out.status = NGX_HTTP_OK;
     }
@@ -400,6 +408,10 @@
 
     ngx_http_perl_set_request(r, ctx);
 
+    if (ctx->variable) {
+        croak("has_request_body(): cannot be used in variable handler");
+    }
+
     if (ctx->next) {
         croak("has_request_body(): another handler active");
     }
@@ -526,6 +538,10 @@
 
     ngx_http_perl_set_request(r, ctx);
 
+    if (ctx->variable) {
+        croak("discard_request_body(): cannot be used in variable handler");
+    }
+
     rc = ngx_http_discard_request_body(r);
 
     if (rc != NGX_OK) {
@@ -551,6 +567,10 @@
         croak("header_out(): called after error");
     }
 
+    if (ctx->variable) {
+        croak("header_out(): cannot be used in variable handler");
+    }
+
     key = ST(1);
     value = ST(2);
 
@@ -640,6 +660,10 @@
         croak("print(): called after error");
     }
 
+    if (ctx->variable) {
+        croak("print(): cannot be used in variable handler");
+    }
+
     if (items == 2) {
 
         /*
@@ -750,6 +774,10 @@
         croak("sendfile(): called after error");
     }
 
+    if (ctx->variable) {
+        croak("sendfile(): cannot be used in variable handler");
+    }
+
     filename = SvPV_nolen(ST(1));
 
     if (filename == NULL) {
@@ -852,6 +880,10 @@
         croak("flush(): called after error");
     }
 
+    if (ctx->variable) {
+        croak("flush(): cannot be used in variable handler");
+    }
+
     b = ngx_calloc_buf(r->pool);
     if (b == NULL) {
         ctx->error = 1;
@@ -883,6 +915,10 @@
 
     ngx_http_perl_set_request(r, ctx);
 
+    if (ctx->variable) {
+        croak("internal_redirect(): cannot be used in variable handler");
+    }
+
     uri = ST(1);
 
     if (ngx_http_perl_sv2str(aTHX_ r, &ctx->redirect_uri, uri) != NGX_OK) {
@@ -911,6 +947,10 @@
 
     ngx_http_perl_set_request(r, ctx);
 
+    if (ctx->variable) {
+        croak("allow_ranges(): cannot be used in variable handler");
+    }
+
     r->allow_ranges = 1;
 
 
@@ -1097,6 +1137,10 @@
 
     ngx_http_perl_set_request(r, ctx);
 
+    if (ctx->variable) {
+        croak("sleep(): cannot be used in variable handler");
+    }
+
     if (ctx->next) {
         croak("sleep(): another handler active");
     }

src/http/modules/perl/ngx_http_perl_module.c

diff --git a/src/http/modules/perl/ngx_http_perl_module.c b/src/http/modules/perl/ngx_http_perl_module.c
index ac6a7a2..a383e90 100644
--- a/src/http/modules/perl/ngx_http_perl_module.c
+++ b/src/http/modules/perl/ngx_http_perl_module.c
@@ -302,6 +302,7 @@
 
     ngx_int_t                   rc;
     ngx_str_t                   value;
+    ngx_uint_t                  saved;
     ngx_http_perl_ctx_t        *ctx;
     ngx_http_perl_main_conf_t  *pmcf;
 
@@ -321,6 +322,9 @@
         ctx->request = r;
     }
 
+    saved = ctx->variable;
+    ctx->variable = 1;
+
     pmcf = ngx_http_get_module_main_conf(r, ngx_http_perl_module);
 
     value.data = NULL;
@@ -347,6 +351,7 @@
         v->not_found = 1;
     }
 
+    ctx->variable = saved;
     ctx->filename.data = NULL;
     ctx->redirect_uri.len = 0;
 

src/http/modules/perl/ngx_http_perl_module.h

diff --git a/src/http/modules/perl/ngx_http_perl_module.h b/src/http/modules/perl/ngx_http_perl_module.h
index 5c967df..b67ce13 100644
--- a/src/http/modules/perl/ngx_http_perl_module.h
+++ b/src/http/modules/perl/ngx_http_perl_module.h
@@ -33,6 +33,7 @@
 
     unsigned                  done:1;
     unsigned                  error:1;
+    unsigned                  variable:1;
 
     ngx_array_t              *variables;  /* array of ngx_http_perl_var_t */