Add function to load in the GPIO data from JSON.
Use the cJSON module to load in the GPIO definitions used by
the other skeleton code into a cJSON structure. Its memory
should be released by calling cJSON_Delete on it when complete.
This is the first commit in a series that will move the GPIO
configuration data from D-Bus into a JSON file, which is both
more appropriate for read only data and the first step in
getting rid of the system_manager.py file that currently hosts it.
Change-Id: If1ef19e7988d28e3075828f61e88a606631bcd89
Signed-off-by: Matt Spinler <spinler@us.ibm.com>
diff --git a/libopenbmc_intf/Makefile b/libopenbmc_intf/Makefile
index df6ccf0..65b1616 100644
--- a/libopenbmc_intf/Makefile
+++ b/libopenbmc_intf/Makefile
@@ -7,7 +7,7 @@
LIBOBMC=$(SONAME).$(VERSION)
INCLUDES=openbmc_intf.h openbmc.h gpio.h gpio_configs.h
-LDLIBS+=$(shell pkg-config --libs $(PACKAGE_DEPS))
+LDLIBS+=$(shell pkg-config --libs $(PACKAGE_DEPS)) -lcjson
ALL_CFLAGS+=$(shell pkg-config --cflags $(PACKAGE_DEPS)) -fPIC -Werror $(CFLAGS)
all: $(SONAME)
@@ -18,7 +18,7 @@
$(SONAME): $(LIBOBMC)
ln -sf $^ $@
-$(LIBOBMC): lib%.so.$(VERSION): %.o gpio.o gpio_configs.o
+$(LIBOBMC): lib%.so.$(VERSION): %.o gpio.o gpio_configs.o gpio_json.o
$(CC) -shared $(CFLAGS) $(LDFLAGS) -Wl,-soname,$(SONAME) \
-o $@ $^ $(LDLIBS)
diff --git a/libopenbmc_intf/gpio_json.c b/libopenbmc_intf/gpio_json.c
new file mode 100644
index 0000000..ae13c90
--- /dev/null
+++ b/libopenbmc_intf/gpio_json.c
@@ -0,0 +1,62 @@
+/**
+ * Copyright © 2018 IBM Corporation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#include <stdio.h>
+#include <stdlib.h>
+#include "gpio_json.h"
+
+#define GPIO_FILE "/etc/default/obmc/gpio/gpio_defs.json"
+
+cJSON* load_json()
+{
+ FILE* fd = fopen(GPIO_FILE, "r");
+ if (!fd)
+ {
+ fprintf(stderr, "Unable to open GPIO JSON file %s\n", GPIO_FILE);
+ return NULL;
+ }
+
+ fseek(fd, 0, SEEK_END);
+ long size = ftell(fd);
+ rewind(fd);
+
+ char* data = malloc(size + 1);
+
+ size_t rc = fread(data, 1, size, fd);
+ fclose(fd);
+ if (rc != size)
+ {
+ free(data);
+ fprintf(stderr, "Only read %d out of %ld bytes of GPIO file %s\n",
+ rc, size, GPIO_FILE);
+ return NULL;
+ }
+
+ data[size] = '\0';
+ cJSON* json = cJSON_Parse(data);
+ free(data);
+
+ if (json == NULL)
+ {
+ fprintf(stderr, "Failed parsing GPIO file %s\n", GPIO_FILE);
+
+ const char* error_loc = cJSON_GetErrorPtr();
+ if (error_loc != NULL)
+ {
+ fprintf(stderr, "JSON error at %s\n", error_loc);
+ }
+ }
+ return json;
+}
diff --git a/libopenbmc_intf/gpio_json.h b/libopenbmc_intf/gpio_json.h
new file mode 100644
index 0000000..b966c98
--- /dev/null
+++ b/libopenbmc_intf/gpio_json.h
@@ -0,0 +1,15 @@
+#ifndef __GPIO_JSON_H__
+#define __GPIO_JSON_H__
+
+#include <cjson/cJSON.h>
+
+/**
+ * Loads the GPIO definitions from JSON into a cJSON structure.
+ *
+ * @return cjSON* - The structure with the GPIO info. Should be freed
+ * with cJSON_Delete() when done. NULL is returned
+ * if there was an error.
+ */
+cJSON* load_json();
+
+#endif