amdfwtool: Move some funtions to other categorized source files

To reduce the size of amdfwtool.c which is already too big.

Change-Id: Ib80eeb42f59a3dda04402b2feaadc1d178ed989e
Signed-off-by: Zheng Bao <fishbaozi@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/73910
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Fred Reitberger <reitbergerfred@gmail.com>

util/amdfwtool/handle_file.c

@@ -0,0 +1,84 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#include <fcntl.h>
+#include <errno.h>
+#include <limits.h>
+#include <stdio.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <string.h>
+#include <stdlib.h>
+
+#include "amdfwtool.h"
+
+void write_or_fail(int fd, void *ptr, size_t size)
+{
+	ssize_t written;
+
+	written = write_from_buf_to_file(fd, ptr, size);
+	if (written < 0 || (size_t)written != size) {
+		fprintf(stderr, "%s: Error writing %zu bytes - written %zd bytes\n",
+								__func__, size, written);
+		exit(-1);
+	}
+}
+
+ssize_t read_from_file_to_buf(int fd, void *buf, size_t buf_size)
+{
+	ssize_t bytes;
+	size_t total_bytes = 0;
+
+	do {
+		bytes = read(fd, buf + total_bytes, buf_size - total_bytes);
+		if (bytes == 0) {
+			fprintf(stderr, "Reached EOF probably\n");
+			break;
+		}
+
+		if (bytes < 0 && errno == EAGAIN)
+			bytes = 0;
+
+		if (bytes < 0) {
+			fprintf(stderr, "Read failure %s\n", strerror(errno));
+			return bytes;
+		}
+
+		total_bytes += bytes;
+	} while (total_bytes < buf_size);
+
+	if (total_bytes != buf_size) {
+		fprintf(stderr, "Read data size(%zu) != buffer size(%zu)\n",
+								total_bytes, buf_size);
+		return -1;
+	}
+	return buf_size;
+}
+
+ssize_t write_from_buf_to_file(int fd, const void *buf, size_t buf_size)
+{
+	ssize_t bytes;
+	size_t total_bytes = 0;
+
+	do {
+		bytes = write(fd, buf + total_bytes, buf_size - total_bytes);
+		if (bytes < 0 && errno == EAGAIN)
+			bytes = 0;
+
+		if (bytes < 0) {
+			fprintf(stderr, "Write failure %s\n", strerror(errno));
+			lseek(fd, SEEK_CUR, -total_bytes);
+			return bytes;
+		}
+
+		total_bytes += bytes;
+	} while (total_bytes < buf_size);
+
+	if (total_bytes != buf_size) {
+		fprintf(stderr, "Wrote more data(%zu) than buffer size(%zu)\n",
+								total_bytes, buf_size);
+		lseek(fd, SEEK_CUR, -total_bytes);
+		return -1;
+	}
+
+	return buf_size;
+}