json: update nvme_dump_config to a file descriptor

This function can be made a bit more flexible where the output is dumped
to by passing in a file descriptor where to dump to.

Signed-off-by: Daniel Wagner <[email protected]>

Author: igaw

fabrics.c

@@ -575,7 +575,7 @@ int fabrics_discovery(const char *desc, int argc, char **argv, bool connect)
 
 out_free:
 	if (dump_config)
-		nvme_dump_config(ctx, NULL);
+		nvme_dump_config(ctx, STDOUT_FILENO);
 
 	return ret;
 }
@@ -678,7 +678,7 @@ int fabrics_connect(const char *desc, int argc, char **argv)
 	}
 
 	if (dump_config)
-		nvme_dump_config(ctx, NULL);
+		nvme_dump_config(ctx, STDERR_FILENO);
 
 	return 0;
 }
@@ -951,11 +951,16 @@ int fabrics_config(const char *desc, int argc, char **argv)
 		}
 	}
 
-	if (update_config)
-		nvme_dump_config(ctx, config_file);
+	if (update_config) {
+		_cleanup_fd_ int fd = -1;
+
+		fd = open(config_file, O_RDONLY, 0);
+		if (fd != -1)
+			nvme_dump_config(ctx, fd);
+	}
 
 	if (dump_config)
-		nvme_dump_config(ctx, NULL);
+		nvme_dump_config(ctx, STDOUT_FILENO);
 
 	return 0;
 }

libnvme/libnvme/nvme.i

@@ -529,7 +529,7 @@ struct nvme_ns {
 		nvme_refresh_topology($self);
 	}
 	void dump_config() {
-		nvme_dump_config($self, NULL);
+		nvme_dump_config($self, STDERR_FILENO);
 	}
 }
 

libnvme/src/nvme/json.c

@@ -386,7 +386,7 @@ static void json_update_subsys(struct json_object *subsys_array,
 	}
 }
 
-int json_update_config(struct nvme_global_ctx *ctx, const char *config_file)
+int json_update_config(struct nvme_global_ctx *ctx, int fd)
 {
 	nvme_host_t h;
 	struct json_object *json_root, *host_obj;
@@ -432,18 +432,12 @@ int json_update_config(struct nvme_global_ctx *ctx, const char *config_file)
 			json_object_put(host_obj);
 		}
 	}
-	if (!config_file) {
-		ret = json_object_to_fd(1, json_root,
-					JSON_C_TO_STRING_PRETTY |
-					JSON_C_TO_STRING_NOSLASHESCAPE);
-		printf("\n");
-	} else
-		ret = json_object_to_file_ext(config_file, json_root,
-					      JSON_C_TO_STRING_PRETTY |
-					      JSON_C_TO_STRING_NOSLASHESCAPE);
+	ret = json_object_to_fd(fd, json_root,
+				JSON_C_TO_STRING_PRETTY |
+				JSON_C_TO_STRING_NOSLASHESCAPE);
+	write(fd, "\n", 1);
 	if (ret < 0) {
-		nvme_msg(ctx, LOG_ERR, "Failed to write to %s, %s\n",
-			 config_file ? "stdout" : config_file,
+		nvme_msg(ctx, LOG_ERR, "Failed to write JSON config file: %s\n",
 			 json_util_get_last_err());
 		ret = -EIO;
 	}

libnvme/src/nvme/private.h

@@ -391,7 +391,7 @@ int nvme_set_attr(const char *dir, const char *attr, const char *value);
 
 int json_read_config(struct nvme_global_ctx *ctx, const char *config_file);
 
-int json_update_config(struct nvme_global_ctx *ctx, const char *config_file);
+int json_update_config(struct nvme_global_ctx *ctx, int fd);
 
 int json_dump_tree(struct nvme_global_ctx *ctx);
 

libnvme/src/nvme/tree.c

@@ -406,9 +406,9 @@ int nvme_scan(const char *config_file, struct nvme_global_ctx **ctxp)
 	return ret;
 }
 
-int nvme_dump_config(struct nvme_global_ctx *ctx, const char *config_file)
+int nvme_dump_config(struct nvme_global_ctx *ctx, int fd)
 {
-	return json_update_config(ctx, config_file);
+	return json_update_config(ctx, fd);
 }
 
 int nvme_dump_tree(struct nvme_global_ctx *ctx)

libnvme/src/nvme/tree.h

@@ -1398,15 +1398,14 @@ void nvme_refresh_topology(struct nvme_global_ctx *ctx);
 /**
  * nvme_dump_config() - Print the JSON configuration
  * @ctx:		&struct nvme_global_ctx object
- * @config_file:	JSON configuration file.
+ * @fd:			File descriptor to write the JSON configuration.
  *
- * Prints the current contents of the JSON configuration
- * file to the config_file. If connfig_file is not provided it prints
- * to stdout.
+ * Writes the current contents of the JSON configuration
+ * to the file descriptor fd.
  *
  * Return: 0 on success, or negative error code otherwise.
  */
-int nvme_dump_config(struct nvme_global_ctx *ctx, const char *config_file);
+int nvme_dump_config(struct nvme_global_ctx *ctx, int fd);
 
 /**
  * nvme_dump_tree() - Dump internal object tree

libnvme/test/config/config-dump.c

@@ -7,6 +7,7 @@
 #include <string.h>
 #include <stdbool.h>
 #include <stdlib.h>
+#include <unistd.h>
 #include <errno.h>
 
 #include <libnvme.h>
@@ -29,7 +30,7 @@ static bool config_dump(const char *file)
 	if (err)
 		goto out;
 
-	err = nvme_dump_config(ctx, NULL);
+	err = nvme_dump_config(ctx, STDOUT_FILENO);
 	if (err)
 		goto out;
 

libnvme/test/config/psk-json.c

@@ -9,6 +9,7 @@
 #include <string.h>
 #include <stdbool.h>
 #include <stdlib.h>
+#include <unistd.h>
 #include <errno.h>
 
 #include <libnvme.h>
@@ -69,7 +70,7 @@ static bool psk_json_test(char *file)
 				if (!import_export_key(ctx, c))
 					goto out;
 
-	err = nvme_dump_config(ctx, NULL);
+	err = nvme_dump_config(ctx, STDOUT_FILENO);
 	if (err)
 		goto out;