util: Let callers pass an offset to read_file

When reading from a dump file, read_file would be more convenient to
use than mem_chunk, but it lacks an offset parameter.

Signed-off-by: Jean Delvare <jdelvare@suse.de>

1 files changed, 11 insertions, 3 deletions

diff --git a/util.c b/util.c
index 538968f..0aafcb1 100644
--- a/util.c
+++ b/util.c
@@ -2,7 +2,7 @@
  * Common "util" functions
  * This file is part of the dmidecode project.
  *
- *   Copyright (C) 2002-2015 Jean Delvare <jdelvare@suse.de>
+ *   Copyright (C) 2002-2017 Jean Delvare <jdelvare@suse.de>
  *
  *   This program is free software; you can redistribute it and/or modify
  *   it under the terms of the GNU General Public License as published by
@@ -89,7 +89,7 @@ int checksum(const u8 *buf, size_t len)
 }
 
 /*
- * Reads all of file, up to max_len bytes.
+ * Reads all of file from given offset, up to max_len bytes.
  * A buffer of max_len bytes is allocated by this function, and
  * needs to be freed by the caller.
  * This provides a similar usage model to mem_chunk()
@@ -98,7 +98,7 @@ int checksum(const u8 *buf, size_t len)
  * sets max_len to the length actually read.
  *
  */
-void *read_file(size_t *max_len, const char *filename)
+void *read_file(off_t base, size_t *max_len, const char *filename)
 {
 	int fd;
 	size_t r2 = 0;
@@ -116,6 +116,14 @@ void *read_file(size_t *max_len, const char *filename)
 		return NULL;
 	}
 
+	if (lseek(fd, base, SEEK_SET) == -1)
+	{
+		fprintf(stderr, "%s: ", filename);
+		perror("lseek");
+		p = NULL;
+		goto out;
+	}
+
 	if ((p = malloc(*max_len)) == NULL)
 	{
 		perror("malloc");