From 03b7473d4faddcb87a5e82205a42028768e7c177 Mon Sep 17 00:00:00 2001
From: Gediminas Jakutis <gediminas@varciai.lt>
Date: Sat, 19 May 2018 12:02:08 +0300
Subject: add support for "live"-flashing new settings.

---
 src/server/util.c | 142 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 142 insertions(+)

(limited to 'src/server/util.c')

diff --git a/src/server/util.c b/src/server/util.c
index bb494c8..4aee886 100644
--- a/src/server/util.c
+++ b/src/server/util.c
@@ -18,12 +18,32 @@
  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
  */
 
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/wait.h>
+#include <gtk/gtk.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <time.h>
+#include <endian.h>
 #include <string.h>
+#include <stdlib.h>
+#include <stdio.h>
 #include "util.h"
 #include "net.h"
+#include "gtk.h"
+
+struct child_data {
+	char **argv;
+	int fd;
+	char *buf;
+};
 
 static float digest_temp(const short int rawtemp);
 static float digest_volt(const short int rawvolt);
+static int find_settings_region(char *start, char *end, char *buf, size_t n);
+static int flash(char *buf, size_t address, size_t size, char* port);
+void reap_dead_children(int pid, int status, void *data);
 
 /*
  * raw data is in 0.1°K per 1. Subtract 2730 to get Celsius.
@@ -57,3 +77,125 @@ int refresh_data(int nd, struct tempmodule_state *state)
 
 	return ret;
 }
+
+
+int write_settings(char *imagename, const struct configuration * const conf)
+{
+	/* the largest flash size supported by ESP-8266 is 16MiB, so let's just use that. */
+	static const size_t flash_size = 16 * 1024 * 1024;
+	char pattern_a[4] = PADDING_START;
+	char pattern_b[4] = PADDING_END;
+	ssize_t buf_used;
+	ssize_t offset;
+	char *buf = NULL;
+	int fd;
+	int ret = ERROR;
+
+	fd = open(imagename, O_RDONLY);
+	if (fd < 0) {
+		goto fail;
+	}
+	buf = malloc(flash_size);
+	buf_used = read(fd, buf, flash_size);
+	close(fd);
+	if (buf_used < sizeof(struct configuration)) {
+		goto fail;
+	}
+
+	offset = find_settings_region(pattern_a, pattern_b, buf, buf_used);
+	if (offset == ERROR) {
+		goto fail;
+	};
+
+	memcpy(buf + offset, conf, sizeof(struct configuration));
+	/* make sure the block written is aligned on 4k boundry
+	 * and is 4k of size.
+	 *
+	 * see:
+	 * https://github.com/espressif/esptool/issues/306
+	 */
+	offset &= ~(0xfff);
+	ret = flash(buf + offset, offset, 4 * 1024, NULL);
+
+fail:
+	free(buf);
+	return ret;
+}
+
+static int find_settings_region(char *start, char *end, char *buf, size_t n)
+{
+	int ret = ERROR;
+	char *a;
+
+	if (!(a = memmem(buf, n, start, 4))) {
+		goto fail;
+	}
+
+	if ((a - buf + sizeof(struct configuration)) > n) {
+		goto fail;
+	}
+
+	if (memcmp(a + sizeof(struct configuration) - 4, end, 4)) {
+		goto fail;
+	}
+
+	ret = a - buf;
+fail:
+	return ret;
+}
+
+static int flash(char *buf, size_t address, size_t size, char* port)
+{
+	static const char esptool[] = "esptool.py";
+	static const char command[] = "write_flash";
+	struct child_data *cdata;
+	char tmpfn[] = "espXXXXXX";	/* temporary file name template */
+	char *fifn;			/* flash image file name */
+	char textbuf[32];
+	char *argv[7] = {0};
+	int ret = ERROR;
+	pid_t pid;
+	int fd;
+	size_t i = 1;
+
+	fd = mkstemp(tmpfn);
+	write(fd, buf, size);
+	fifn = malloc(0x100);
+	memset(fifn, '\0', 0x100);
+	sprintf(textbuf, "/proc/self/fd/%d", fd);
+	if (readlink(textbuf, fifn, 0x100) == -1) {
+		exit(TMPFILE);
+	}
+
+	argv[0] = strdup(esptool);
+	if (port) {
+		argv[i++] = strdup("--port");
+		argv[i++] = strdup(port);
+	}
+	argv[i++] = strdup(command);
+	sprintf(textbuf, "%#.4lx", address);
+	argv[i++] = strdup(textbuf);
+	argv[i++] = strdup(fifn);
+	argv[i] = NULL;
+
+	cdata = malloc(sizeof(*cdata));
+	cdata->argv = argv;
+	cdata->fd = fd;
+	cdata->buf = fifn;
+
+	g_spawn_async_with_pipes(NULL, argv, NULL, G_SPAWN_SEARCH_PATH | G_SPAWN_LEAVE_DESCRIPTORS_OPEN | G_SPAWN_DO_NOT_REAP_CHILD, NULL, NULL, &pid, NULL, NULL, NULL, NULL);
+	g_child_watch_add(pid, reap_dead_children, cdata);
+	return ret;
+}
+
+void reap_dead_children(int pid, int status, void *data)
+{
+	struct child_data *a;
+
+	a = data;
+	free(a->buf);
+	close(a->fd);
+	free(data);
+	g_spawn_close_pid(pid);
+	gtkui_dialog_done(status);
+}
-- 
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