1 files changed, 168 insertions, 0 deletions
diff --git a/scripts/common.c b/scripts/common.c
new file mode 100644
index 0000000000..b780b09941
--- /dev/null
+++ b/scripts/common.c
@@ -0,0 +1,168 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+#include <stdio.h>
+#include <sys/types.h>
+#include <stdint.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <errno.h>
+#include <stdarg.h>
+#include <sys/mman.h>
+
+#include "common.h"
+
+int read_file_2(const char *filename, size_t *size, void **outbuf, size_t max_size)
+{
+	off_t fsize;
+	ssize_t rsize;
+	int ret, fd;
+	void *buf;
+
+	*size = 0;
+	*outbuf = NULL;
+
+	fd = open(filename, O_RDONLY);
+	if (fd < 0) {
+		fprintf(stderr, "Cannot open %s: %s\n", filename, strerror(errno));
+		return -errno;
+	}
+
+	fsize = lseek(fd, 0, SEEK_END);
+	if (fsize == -1) {
+		fprintf(stderr, "Cannot get size %s: %s\n", filename, strerror(errno));
+		ret = -errno;
+		goto close;
+	}
+
+	if (fsize < max_size)
+		max_size = fsize;
+
+	if (lseek(fd, 0, SEEK_SET) == -1) {
+		fprintf(stderr, "Cannot seek to start %s: %s\n", filename, strerror(errno));
+		ret = -errno;
+		goto close;
+	}
+
+	buf = mmap(NULL, max_size, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0);
+	if (buf == MAP_FAILED ) {
+		buf = malloc(max_size);
+		if (!buf) {
+			fprintf(stderr, "Cannot allocate memory\n");
+			ret = -ENOMEM;
+			goto close;
+		}
+
+		*outbuf = buf;
+
+		while (*size < max_size) {
+			rsize = read(fd, buf, max_size - *size);
+			if (rsize == 0) {
+				ret = -EIO;
+				goto free;
+			}
+
+			if (rsize < 0) {
+				ret = -errno;
+				goto free;
+			}
+
+			buf += rsize;
+			*size += rsize;
+		}
+	} else {
+		*outbuf = buf;
+		*size = max_size;
+	}
+
+	ret = 0;
+	goto close;
+free:
+	*outbuf = NULL;
+	free(buf);
+close:
+	close(fd);
+	return ret;
+}
+
+void *read_file(const char *filename, size_t *size)
+{
+	int ret;
+	void *buf;
+
+	ret = read_file_2(filename, size, &buf, (size_t)-1);
+	if (!ret)
+		return buf;
+
+	errno = -ret;
+
+	return NULL;
+}
+
+int write_file(const char *filename, const void *buf, size_t size)
+{
+	int fd, ret = 0;
+	int now;
+
+	fd = open(filename, O_WRONLY | O_TRUNC | O_CREAT,
+		  S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH);
+	if (fd < 0) {
+		fprintf(stderr, "Cannot open %s: %s\n", filename, strerror(errno));
+		return -errno;
+	}
+
+	while (size) {
+		now = write(fd, buf, size);
+		if (now < 0) {
+			fprintf(stderr, "Cannot write to %s: %s\n", filename,
+				strerror(errno));
+			ret = -errno;
+			goto out;
+		}
+		size -= now;
+		buf += now;
+	}
+
+out:
+	close(fd);
+
+	return ret;
+}
+
+int read_full(int fd, void *buf, size_t size)
+{
+	size_t insize = size;
+	int now;
+	int total = 0;
+
+	while (size) {
+		now = read(fd, buf, size);
+		if (now == 0)
+			return total;
+		if (now < 0)
+			return now;
+		total += now;
+		size -= now;
+		buf += now;
+	}
+
+	return insize;
+}
+
+int write_full(int fd, void *buf, size_t size)
+{
+	size_t insize = size;
+	int now;
+
+	while (size) {
+		now = write(fd, buf, size);
+		if (now <= 0)
+			return now;
+		size -= now;
+		buf += now;
+	}
+
+	return insize;
+}