firmware: Add search path

This adds a colon separated search path for firmware files. When the
firmware we are searching is not an absolute path then look in the
search path first. This will be useful later when the bootloader spec
implementation shall look for firmware files relative to the provided
root.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Link: https://lore.barebox.org/20210624085223.14616-8-s.hauer@pengutronix.de
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

1 files changed, 41 insertions, 0 deletions

diff --git a/common/firmware.c b/common/firmware.c
index fa4f585693..477dc1f13a 100644
--- a/common/firmware.c
+++ b/common/firmware.c
@@ -11,6 +11,8 @@
 #include <libbb.h>
 #include <libfile.h>
 #include <fs.h>
+#include <globalvar.h>
+#include <magicvar.h>
 #include <linux/list.h>
 #include <linux/stat.h>
 #include <linux/err.h>
@@ -208,6 +210,26 @@ out:
 	return ret;
 }
 
+static char *firmware_path;
+
+const char *firmware_get_searchpath(void)
+{
+	return firmware_path;
+}
+
+void firmware_set_searchpath(const char *path)
+{
+	free(firmware_path);
+	firmware_path = strdup(path);
+}
+
+static bool file_exists(const char *filename)
+{
+	struct stat s;
+
+	return !stat(filename, &s);
+}
+
 /*
  * firmware_load_file - load a firmware to a device
  */
@@ -216,6 +238,7 @@ int firmwaremgr_load_file(struct firmware_mgr *mgr, const char *firmware)
 	char *dst;
 	enum filetype type;
 	int ret = 0;
+	char *fw = NULL;
 	int firmwarefd = 0;
 	int devicefd = 0;
 
@@ -229,6 +252,12 @@ int firmwaremgr_load_file(struct firmware_mgr *mgr, const char *firmware)
 
 	dst = basprintf("/dev/%s", mgr->handler->id);
 
+	if (*firmware != '/') {
+		fw = find_path(firmware_path, firmware, file_exists);
+		if (fw)
+			firmware = fw;
+	}
+
 	firmwarefd = open(firmware, O_RDONLY);
 	if (firmwarefd < 0) {
 		printf("could not open %s: %s\n", firmware,
@@ -254,6 +283,7 @@ int firmwaremgr_load_file(struct firmware_mgr *mgr, const char *firmware)
 
 out:
 	free(dst);
+	free(fw);
 
 	if (firmwarefd > 0)
 		close(firmwarefd);
@@ -262,3 +292,14 @@ out:
 
 	return ret;
 }
+
+static int firmware_init(void)
+{
+	firmware_path = strdup("/env/firmware");
+	globalvar_add_simple_string("firmware.path", &firmware_path);
+
+	return 0;
+}
+device_initcall(firmware_init);
+
+BAREBOX_MAGICVAR(global.firmware.path, "Firmware search path");