diff --git a/README b/README
new file mode 100644
index 0000000..a123ee7
--- /dev/null
+++ b/README
@@ -0,0 +1,45 @@
+mod_rrd_graph
+=============
+
+RRDtool[1] stores and graphs time-series data. ngx_rrd_graph provides an HTTP
+interface to RRDtool's graphing facilities. By linking RRDtool code directly
+into Nginx, it is faster than scripts and CGIs with similar purposes.
+
+To install, compile nginx with this option:
+
+    --add-module=/path/to/this/directory
+
+ngx_rrd_graph requires RRDtool 1.3 or later. 
+
+After compiling, installing, and restarting Nginx, ngx_rrd_graph can be enabled
+at a particular location with the "rrd_graph" directive, like so:
+
+    location /rrdtool {
+        rrd_graph;
+    }
+
+RRDtool graphing commands can then be appended to that location in request
+URLs. The syntax is just the same as the arguments to the "rrdtool graph"
+command, omitting the filename. (Refer to rrdgraph(1).) These commands should
+be URL-encoded, so that this command-line invocation:
+
+    rrdtool graph --start now-300s \
+                  --end now \
+                  DEF:ds0=test.rrd:reading:AVERAGE \
+                  LINE1:ds0#00FF00
+
+becomes:
+
+    http://mysite.com/rrdtool--start%20now-300s%20--end%20now%20DEF%3Ads0%3Dtest.rrd%3Areading%3AAVERAGE%20LINE1%3Ads0%2300FF00
+
+The module supports all the features of your copy of RRDtool. It can output
+PNG, PDF, SVG, and EPS graphics (see the --imgformat option of rrdgraph(1)).
+
+If you'd prefer not to provide absolute paths to files referenced in DEF commands,
+you may supply a root directory with the "rrd_graph_root" directive. Files mentioned
+in DEF commands will be automatically prefixed with the value of rrd_graph_root.
+As of this writing there are no guards against relative paths (e.g. "..").
+
+Questions/comments to emmiller@gmail.com.
+
+[1] http://oss.oetiker.ch/rrdtool/
diff --git a/config b/config
new file mode 100644
index 0000000..73b8204
--- /dev/null
+++ b/config
@@ -0,0 +1,20 @@
+ngx_feature="RRDtool"
+ngx_feature_name=
+ngx_feature_run=no
+ngx_feature_incs="#include <rrd.h>"
+ngx_feature_path=
+ngx_feature_libs=-lrrd
+ngx_feature_test="rrd_graph_v;"
+. auto/feature
+
+if [ $ngx_found = yes ]; then
+    ngx_addon_name=ngx_http_rrd_graph_module
+    HTTP_MODULES="$HTTP_MODULES ngx_http_rrd_graph_module"
+    NGX_ADDON_SRCS="$NGX_ADDON_SRCS $ngx_addon_dir/ngx_http_rrd_graph_module.c"
+    CORE_LIBS="$CORE_LIBS -lrrd"
+else
+    cat << END
+$0: error: ngx_rrd_graph requires RRDtool 1.3 or later.
+END
+    exit 1
+fi
diff --git a/ngx_http_rrd_graph_module.c b/ngx_http_rrd_graph_module.c
new file mode 100644
index 0000000..ad305e3
--- /dev/null
+++ b/ngx_http_rrd_graph_module.c
@@ -0,0 +1,295 @@
+/*
+ * mod_rrd_graph - Graph data in a Round Robin Database (RRD).
+ * 
+ * Copyright (C) Evan Miller
+ */
+
+#include <ngx_config.h>
+#include <ngx_core.h>
+#include <ngx_http.h>
+#include <rrd.h>
+
+typedef struct {
+    ngx_str_t      root;
+} ngx_http_rrd_graph_conf_t;
+
+static void * ngx_http_rrd_graph_create_conf(ngx_conf_t *cf);
+static char * ngx_http_rrd_graph_merge_conf(ngx_conf_t *cf, void *parent, void *child);
+static char* ngx_http_rrd_graph(ngx_conf_t *cf, ngx_command_t *cmd, void *conf);
+static ngx_int_t ngx_http_rrd_graph_handler(ngx_http_request_t *r);
+static ngx_int_t ngx_http_rrd_graph_send_image(ngx_http_request_t *r, u_char *image, size_t image_size);
+static ngx_int_t ngx_http_rrd_graph_parse_uri(ngx_http_request_t *r, int *argc_ptr, 
+        char ***argv_ptr, size_t **argv_len_ptr);
+
+static u_char ngx_http_png_header[] = { '\x89', 'P', 'N', 'G' };
+static u_char ngx_http_pdf_header[] = { '%', 'P', 'D', 'F' };
+static u_char ngx_http_svg_header[] = { '<', '?', 'x', 'm', 'l' };
+static u_char ngx_http_eps_header[] = { '%', '!', 'P', 'S' };
+
+static ngx_command_t  ngx_http_rrd_graph_commands[] = {
+    { ngx_string("rrd_graph"),
+      NGX_HTTP_LOC_CONF|NGX_CONF_NOARGS,
+      ngx_http_rrd_graph,
+      0,
+      0,
+      NULL },
+
+/* the root directory that will be prefixed to file names */
+    { ngx_string("rrd_graph_root"),
+      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
+      ngx_conf_set_str_slot,
+      NGX_HTTP_LOC_CONF_OFFSET,
+      offsetof(ngx_http_rrd_graph_conf_t, root),
+      NULL },
+
+      ngx_null_command
+};
+
+
+static ngx_http_module_t  ngx_http_rrd_graph_module_ctx = {
+    NULL,                          /* preconfiguration */
+    NULL,                          /* postconfiguration */
+
+    NULL,                          /* create main configuration */
+    NULL,                          /* init main configuration */
+
+    NULL,                          /* create server configuration */
+    NULL,                          /* merge server configuration */
+
+    ngx_http_rrd_graph_create_conf,/* create location configuration */
+    ngx_http_rrd_graph_merge_conf  /* merge location configuration */
+};
+
+
+ngx_module_t  ngx_http_rrd_graph_module = {
+    NGX_MODULE_V1,
+    &ngx_http_rrd_graph_module_ctx, /* module context */
+    ngx_http_rrd_graph_commands,   /* module directives */
+    NGX_HTTP_MODULE,               /* module type */
+    NULL,                          /* init master */
+    NULL,                          /* init module */
+    NULL,                          /* init process */
+    NULL,                          /* init thread */
+    NULL,                          /* exit thread */
+    NULL,                          /* exit process */
+    NULL,                          /* exit master */
+    NGX_MODULE_V1_PADDING
+};
+
+
+static ngx_int_t
+ngx_http_rrd_graph_handler(ngx_http_request_t *r)
+{
+    ngx_int_t     rc;
+    /* image metadata */
+    rrd_info_t   *image_info = NULL, *walker;
+    u_char       *image = NULL, *tmp;
+    size_t        image_size = 0;
+
+    int           argc = 3; /* two dummies + at least one real */
+    char        **argv;
+    size_t       *argv_len;
+
+    if (!(r->method & (NGX_HTTP_GET|NGX_HTTP_HEAD)))
+        return NGX_HTTP_NOT_ALLOWED;
+
+    rc = ngx_http_discard_request_body(r);
+    if (rc != NGX_OK && rc != NGX_AGAIN)
+        return rc;
+
+    if ((rc = ngx_http_rrd_graph_parse_uri(r, &argc, &argv, &argv_len)) != NGX_OK)
+        return rc;
+
+    image_info = rrd_graph_v(argc, argv);
+
+    if (rrd_test_error()) {
+	ngx_log_error(NGX_LOG_ERR, r->connection->log, 0, "mod_rrd_graph: RRD graph failed: %s", rrd_get_error());
+        rrd_clear_error();
+        rrd_info_free(image_info);
+        return NGX_HTTP_INTERNAL_SERVER_ERROR;
+    }
+
+    for (walker = image_info; walker; walker = walker->next) {
+        ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                "mod_rrd_graph: found key '%s'", walker->key);
+        if (ngx_strcmp(walker->key, "image") == 0) {
+            image = walker->value.u_blo.ptr;
+            image_size = walker->value.u_blo.size;
+            ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                    "mod_rrd_graph: image size is %d bytes", image_size);
+        }
+    }
+
+    if (image_size) {
+        if ((tmp = ngx_palloc(r->pool, image_size)) == NULL) {
+            ngx_log_error(NGX_LOG_ERR, r->connection->log, 0, 
+                    "mod_rrd_graph: Failed to allocate response buffer.");
+            return NGX_HTTP_INTERNAL_SERVER_ERROR;
+        }
+        ngx_memcpy(tmp, image, image_size);
+        rrd_info_free(image_info); 
+        return ngx_http_rrd_graph_send_image(r, tmp, image_size);
+    }
+
+    rrd_info_free(image_info); 
+
+    return NGX_HTTP_NOT_FOUND;
+}
+
+static char *
+ngx_http_rrd_graph(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
+{
+    ngx_http_core_loc_conf_t  *clcf;
+
+    clcf = ngx_http_conf_get_module_loc_conf(cf, ngx_http_core_module);
+    clcf->handler = ngx_http_rrd_graph_handler;
+
+    return NGX_CONF_OK;
+}
+
+static ngx_int_t
+ngx_http_rrd_graph_parse_uri(ngx_http_request_t *r, int *argc_ptr, 
+    char ***argv_ptr, size_t **argv_len_ptr)
+{
+    int i,   argc = 3;
+    char   **argv;
+    size_t  *argv_len;
+    char *tmp, *p;
+    u_char *uri_copy;
+    ngx_http_core_loc_conf_t  *clcf;
+    ngx_http_rrd_graph_conf_t *conf;
+
+    clcf = ngx_http_get_module_loc_conf(r, ngx_http_core_module);
+
+    if (r->uri.len == clcf->name.len)
+        return NGX_HTTP_NOT_FOUND;
+
+    /* tokenize */
+    if ((uri_copy = ngx_palloc(r->pool, (r->uri.len + 1)*sizeof(char))) == NULL) {
+	ngx_log_error(NGX_LOG_ERR, r->connection->log, 0, "mod_rrd_graph: Failed to copy URI.");
+        return NGX_HTTP_INTERNAL_SERVER_ERROR;
+    }
+
+    ngx_memcpy(uri_copy, r->uri.data, r->uri.len);
+    uri_copy[r->uri.len] = '\0'; /* RRDtool needs null-terminated strings */
+    p = (char *)uri_copy + clcf->name.len;
+
+    while(*p++)
+        if (*p == ' ')
+            argc++;
+
+    argv     = ngx_palloc(r->pool, argc*sizeof(char *));
+    argv_len = ngx_pcalloc(r->pool, argc*sizeof(size_t));
+    argv[0] = "mod_rrd_graph";
+    argv[1] = "-";
+    argv[2] = p = (char *)uri_copy + clcf->name.len;
+    argc = 3;
+    while (*p) {
+        if (*p == ' ') {
+            *p = '\0';
+            argv[argc++] = p+1;
+        } else {
+            argv_len[argc-1]++;
+        }
+        p++;
+    }
+
+    conf = ngx_http_get_module_loc_conf(r, ngx_http_rrd_graph_module);
+    /* splice in the RRD directory root */
+    /* TODO guard against relative paths */
+    for (i=2; i<argc; i++) {
+        if (ngx_strncmp(argv[i], "DEF:", sizeof("DEF:") - 1) == 0) {
+            p = argv[i] + sizeof("DEF:") - 1;
+            if ((p = ngx_strchr(p, '=')) != NULL) {
+                p++;
+                tmp = ngx_pcalloc(r->pool, argv_len[i] + conf->root.len + 1);
+                ngx_memcpy(tmp, argv[i], p - argv[i]); /* prefix */
+                ngx_memcpy(tmp + (p - argv[i]), conf->root.data, conf->root.len); /* root dir */
+                ngx_memcpy(tmp + (p - argv[i]) + conf->root.len, /* suffix */
+                        p, argv_len[i] - (p - argv[i]));
+                argv[i] = tmp;
+            }
+        }
+        ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                "mod_rrd_graph: parsed arg %s", argv[i]);
+    }
+    *argc_ptr = argc;
+    *argv_ptr = argv;
+    *argv_len_ptr = argv_len;
+    return NGX_OK;
+}
+
+static ngx_int_t
+ngx_http_rrd_graph_send_image(ngx_http_request_t *r, u_char *image, size_t image_size)
+{
+    int rc;
+    ngx_chain_t   out;
+
+    out.next = NULL;
+    if ((out.buf = ngx_pcalloc(r->pool, sizeof(ngx_buf_t))) == NULL) {
+	ngx_log_error(NGX_LOG_ERR, r->connection->log, 0, "mod_rrd_graph: Failed to allocate response buffer.");
+        free(image);
+        return NGX_HTTP_INTERNAL_SERVER_ERROR;
+    }
+
+    if (image_size > 4) {
+        if (ngx_strncmp(image, ngx_http_png_header, 
+                    sizeof(ngx_http_png_header)) == 0) {
+            r->headers_out.content_type.len = sizeof("image/png") - 1;
+            r->headers_out.content_type.data = (u_char *)"image/png";
+        } else if (ngx_strncmp(image, ngx_http_pdf_header,
+                    sizeof(ngx_http_pdf_header)) == 0) {
+            r->headers_out.content_type.len = sizeof("application/pdf") - 1;
+            r->headers_out.content_type.data = (u_char *)"application/pdf";
+        } else if (ngx_strncmp(image, ngx_http_eps_header,
+                    sizeof(ngx_http_eps_header)) == 0) {
+            r->headers_out.content_type.len = sizeof("application/postscript") - 1;
+            r->headers_out.content_type.data = (u_char *)"application/postscript";
+        } else if (ngx_strncmp(image, ngx_http_svg_header,
+                    sizeof(ngx_http_svg_header)) == 0) {
+            r->headers_out.content_type.len = sizeof("image/svg+xml") - 1;
+            r->headers_out.content_type.data = (u_char *)"image/svg+xml";
+        }
+    }
+
+    r->headers_out.status = NGX_HTTP_OK;
+    r->headers_out.content_length_n = image_size;
+
+    rc = ngx_http_send_header(r);
+
+    if (rc == NGX_ERROR || rc > NGX_OK || r->header_only) {
+        free(image);
+        return rc;
+    }
+
+    out.buf->pos = image;
+    out.buf->last = image + image_size;
+
+    out.buf->memory = 1;
+    out.buf->last_buf = 1;
+
+    return ngx_http_output_filter(r, &out);
+}
+
+static void *
+ngx_http_rrd_graph_create_conf(ngx_conf_t *cf)
+{
+    ngx_http_rrd_graph_conf_t  *conf;
+
+    conf = ngx_pcalloc(cf->pool, sizeof(ngx_http_rrd_graph_conf_t));
+    if (conf == NULL) {
+        return NGX_CONF_ERROR;
+    }
+    return conf;
+}
+
+static char *
+ngx_http_rrd_graph_merge_conf(ngx_conf_t *cf, void *parent, void *child)
+{
+        ngx_http_rrd_graph_conf_t *prev = parent;
+        ngx_http_rrd_graph_conf_t *conf = child;
+
+        ngx_conf_merge_str_value(conf->root, prev->root, "");
+
+        return NGX_CONF_OK;
+}