examples/lwnbd-server.c : fix conccurency issue

.env

@@ -3,4 +3,5 @@ LWNBD_DEBUG=1
 NBD_URI=1
 TARGET_IP=192.168.1.10
 MAKE_SILENT=1
+#MAKE_FATAL=1
 WORKSPACE="../workspace/"

Makefile

@@ -6,7 +6,7 @@
 CC ?= gcc
 # TODO: can't use -pedantic-errors yet due to LOG macros
 # 
-CFLAGS = -Iinclude -std=c99 -Wall -Wfatal-errors
+CFLAGS = -Iinclude -std=c99 -Wall
 DEBUG ?= 0
 
 APP_VERSION := $(shell git describe --always --tags)
@@ -15,9 +15,6 @@ TARGET ?= unix
 RONN = ronn
 MANPAGE = lwnbd.3
 
-$(BIN): banner $(OBJ)
-	$(CC) $(CFLAGS) -o $(BIN) $(OBJ) $(LDFLAGS) $(LIBS)
-
 include .env
 include src/Makefile
 
@@ -46,9 +43,16 @@ ifeq ($(MAKE_SILENT),1)
 .SILENT: $(OBJ)
 endif
 
+ifeq ($(MAKE_FATAL),1)
+	CFLAGS += -Wfatal-errors
+endif
+
 $(MANPAGE): README.md
 	$(RONN) -r --pipe $< > $@
 
+$(BIN): banner $(OBJ)
+	$(CC) $(CFLAGS) -o $(BIN) $(OBJ) $(LDFLAGS) $(LIBS)
+
 banner:
 	@echo "       _  _  _ __   _ ______  ______"
 	@echo "|      |  |  | | \\  | |_____] |     \\"
@@ -58,7 +62,7 @@ banner:
 
 clean:
 	rm -f $(BIN) $(MANPAGE) $(OBJ) *~ core
-	find -iname "*.o" -or -iname "*.a" -exec rm {} \;
+	find -iname "*.o" -exec rm -f {} \;
 
 nbdcleanup:
 	sudo lsof -t /dev/nbd* | sudo xargs -r kill -9

examples/Makefile

@@ -2,7 +2,7 @@ BIN = local-reader \
 	local-shell \
 	lwnbd-server
 
-CFLAGS = -I../include $(CFLAGS-$@) -g
+CFLAGS = -I../include $(CFLAGS-$@) -DLWNBD_DEBUG
 LWNBD_LIB := ../lwnbd.a
 LDLIBS := $(LWNBD_LIB)
 LDFLAGS += $(LDFLAGS-$@)

examples/local-reader.c

@@ -7,8 +7,6 @@
 #include <stdlib.h>
 #include <unistd.h>
 
-extern struct lwnbd_plugin_t *file_plugin_init(void);
-
 int main(int argc, const char **argv)
 {
     lwnbd_plugin_h fileplg;

examples/local-shell.c

@@ -1,6 +1,8 @@
 /*
  * An interactive shell using command plugin
  *
+ *
+ *
  */
 
 #define _GNU_SOURCE
@@ -10,9 +12,6 @@
 #include <stdio.h>
 #include <string.h>
 #include <unistd.h>
-#include <lwnbd-plugin.h>
-
-extern struct lwnbd_plugin_t *command_plugin_init(void);
 
 char *exportname, *prompt, *base;
 
@@ -37,13 +36,17 @@ static int set_exportname(int argc, char **argv, void *result, int64_t *size)
 
 int main(int argc, char **argv)
 {
-    lwnbd_plugin_h cmdplg;
+    lwnbd_plugin_h cmdplg, memplg;
     lwnbd_context_t *ctx;
-    char *p, *buf;
+    char *p, *buf, memtest[512];
     int errno, r = 0;
-    ;
     uint64_t size = 0;
 
+    /*
+     * set base URI, default exportname to 'shell' and prompt
+     *
+     */
+
     if (-1 == asprintf(&exportname, "shell"))
         exit(EXIT_FAILURE);
 
@@ -53,6 +56,34 @@ int main(int argc, char **argv)
     if (-1 == set_prompt(base, exportname))
         exit(EXIT_FAILURE);
 
+    /*
+     * create a slice of memory to test memory query
+     *
+     */
+
+    memplg = lwnbd_plugin_init(memory_plugin_init);
+
+    struct memory_config memh = {
+        .base = (uint64_t)memtest,
+        .name = "test",
+        .size = 512,
+        .desc = "",
+    };
+    lwnbd_plugin_new(memplg, &memh);
+
+    /*
+     * let's use query mechanism to set it
+     */
+
+    if (-1 == asprintf(&buf, "test?memcpy=Example of shared memory.\n")) /* create the request */
+        exit(EXIT_FAILURE);
+
+    ctx = lwnbd_get_context(buf); /* GET */
+
+    /*
+     * create a command to change export, to be able to switch to it
+     */
+
     cmdplg = lwnbd_plugin_init(command_plugin_init);
 
     struct lwnbd_command mycmd = {
@@ -63,6 +94,10 @@ int main(int argc, char **argv)
 
     lwnbd_plugin_new(cmdplg, &mycmd);
 
+    /*
+     * main 'interactive' shell loop
+     */
+
     while (r == 0) {
         int n;
 
@@ -84,6 +119,8 @@ int main(int argc, char **argv)
         }
 
         ctx = lwnbd_get_context(buf);
+        if (ctx == NULL)
+            continue;
 
         if (size < ctx->exportsize) {
             size = ctx->exportsize;
@@ -94,5 +131,9 @@ int main(int argc, char **argv)
         printf("%s", buf);
     }
 
+    free(buf);
+    free(exportname);
+    free(prompt);
+    free(base);
     exit(EXIT_SUCCESS);
 }

examples/lwnbd-server.c

@@ -15,33 +15,32 @@
 #include <assert.h>
 #include <errno.h>
 #include <fcntl.h>
+#include <lwnbd/nbd.h>
 #include <lwnbd.h>
 #include <signal.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <uv.h>
 
-#include "../plugins/memory/memory.h"
-#include "../servers/nbd/nbd.h"
+typedef enum {
+    CLIENT_FREE,
+    CLIENT_INUSE,
+} worker_state_t;
 
-/* static glue, could be generate :
- * #define LIST_ENTRY(x) x,
- *
- * */
-
-extern lwnbd_plugin_t *command_plugin_init(void);
-extern lwnbd_plugin_t *memory_plugin_init(void);
-extern lwnbd_plugin_t *file_plugin_init(void);
-extern struct lwnbd_server *nbd_server_init(void);
+struct nbd_worker
+{
+    uv_work_t req;
+    int client_id;
+    uv_stream_t *server;
+};
 
-#define MAX_CLIENTS 10
-uv_work_t *client_reqs[MAX_CLIENTS];
+#define MAX_CLIENTS 3
+int gEnableWrite = 1;
+int gHDDStartMode;
 
-// plugin_init plugins_table[] = {
-//		file_plugin_init,
-//		NULL
-// };
+static worker_state_t client_states[MAX_CLIENTS];
+struct nbd_worker *client_reqs[MAX_CLIENTS]; /* need to be accessible to signal handler */
 
 void signal_handler(uv_signal_t *req, int signum)
 {
@@ -66,17 +65,17 @@ int server_shutdown(int argc, char **argv, void *result, int64_t *size)
     return 0;
 }
 
-int gEnableWrite = 1;
-int gHDDStartMode;
-
-void on_close(uv_handle_t *handle)
+void on_after_work(uv_work_t *req, int status)
 {
-    free(handle);
+    struct nbd_worker *client_reqs = (struct nbd_worker *)req;
+    client_states[client_reqs->client_id] = CLIENT_FREE;
+    free(req);
 }
 
-void on_after_work(uv_work_t *req, int status)
+void on_close(uv_handle_t *handle)
 {
-    free(req);
+    DEBUGLOG("on_close\n");
+    free(handle);
 }
 
 /*
@@ -86,7 +85,8 @@ void on_after_work(uv_work_t *req, int status)
 void on_work(uv_work_t *req)
 {
     /* a bit of headache but avoid a baton */
-    uv_stream_t *server = (uv_stream_t *)req->data;
+    struct nbd_worker *client_reqs = (struct nbd_worker *)req;
+    uv_stream_t *server = (uv_stream_t *)client_reqs->server;
     lwnbd_server_t *s = (lwnbd_server_t *)server->data;
 
     uv_tcp_t *client = (uv_tcp_t *)malloc(sizeof(uv_tcp_t));
@@ -101,8 +101,10 @@ void on_work(uv_work_t *req)
 
     int sock;
     uv_fileno((const uv_handle_t *)client, &sock);
+    DEBUGLOG("/++++++++++++++++++++++++++++++++++++++++++++++++++\n");
     DEBUGLOG("Worker %d: Accepted fd %d\n", getpid(), sock);
     lwnbd_server_run(*s, &sock); // the abstracted blocking loop
+    DEBUGLOG("+++++++++++++++++++++++++++++++++++++++++++++++++++/\n");
     uv_close((uv_handle_t *)client, on_close);
 }
 
@@ -116,19 +118,19 @@ void on_new_connection(uv_stream_t *server, int status)
     }
 
     for (i = 0; i < MAX_CLIENTS; i++) {
-        if (client_reqs[i] == NULL) {
-            client_reqs[i] = (uv_work_t *)malloc(sizeof(uv_work_t));
-            break;
+        DEBUGLOG("client_reqs[%d] = %p\n", i, client_reqs[i]);
+        if (client_states[i] == CLIENT_FREE) {
+            client_reqs[i] = (struct nbd_worker *)malloc(sizeof(struct nbd_worker));
+            client_states[i] = CLIENT_INUSE;
+            client_reqs[i]->client_id = i;
+            client_reqs[i]->server = server;
+            uv_queue_work(uv_default_loop(), (uv_work_t *)client_reqs[i], on_work, on_after_work);
+            return;
         }
     }
 
-    if (client_reqs[i] == NULL) {
-        LOG("New connection error : no slot available\n");
-        return;
-    }
-
-    client_reqs[i]->data = server;
-    uv_queue_work(uv_default_loop(), client_reqs[i], on_work, on_after_work);
+    LOG("New connection error : no slot available\n");
+    return;
 }
 
 int main(int argc, const char **argv)
@@ -234,5 +236,7 @@ int main(int argc, const char **argv)
     uv_signal_init(loop, &sig);
     uv_signal_start(&sig, signal_handler, SIGINT);
 
+    memset(client_states, CLIENT_FREE, sizeof(client_states));
+
     return uv_run(loop, UV_RUN_DEFAULT);
 }

include/config.h

@@ -36,7 +36,7 @@ extern "C" {
 
 /* plugins options - useless here ? */
 
-#define MAX_NUM_PLUGINS 5
+#define MAX_NUM_PLUGINS 10
 #define MAX_CONTEXTS    10
 
 #ifdef __cplusplus

include/lwnbd-common.h

@@ -0,0 +1,56 @@
+/*
+ *
+ */
+
+#ifndef INCLUDE_LWNBD_COMMON_H_
+#define INCLUDE_LWNBD_COMMON_H_
+
+#include "config.h"
+#include <stdint.h>
+
+/*
+ *
+ */
+
+/* experimental */
+//#ifdef PLUGIN_COMMAND
+extern struct lwnbd_plugin_t *command_plugin_init(void);
+struct lwnbd_command
+{
+    char *name;
+    char *desc;
+    int (*cmd)(int argc, char **argv, void *result, int64_t *size);
+};
+//#endif
+
+//#ifdef PLUGIN_MEMORY
+extern struct lwnbd_plugin_t *memory_plugin_init(void);
+struct memory_config
+{
+    intptr_t base;
+    intptr_t size;
+    char name[32];
+    char desc[64]; /* export description */
+    /* TODO readonly ? */
+};
+//#endif
+
+//#ifdef PLUGIN_PCMSTREAM
+
+struct pcmstream_config
+{
+    char name[32];
+    char desc[64]; /* export description */
+                   //    char format[32];
+    int rate;      /** output frequency in hz */
+    int bits;      /** bits per sample (8, 16) */
+    int channels;  /** output channels (1, 2) */
+    char volume;
+    /* input => readonly or output => writeonly */
+};
+//#endif
+
+extern struct lwnbd_plugin_t *file_plugin_init(void);
+extern struct lwnbd_server *nbd_server_init(void);
+
+#endif /* INCLUDE_LWNBD_COMMON_H_ */