From 868843fbf76dd67e804bc8a02121f5b56c560621 Mon Sep 17 00:00:00 2001
From: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
Date: Sat, 15 Jun 2019 14:48:29 +0200
Subject: Move function to padd a file with 0 bytes to libutil

Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
---
 include/util.h       |  7 +++++++
 lib/Makemodule.am    |  2 +-
 lib/util/padd_file.c | 41 +++++++++++++++++++++++++++++++++++++++++
 mkfs/mkfs.c          | 37 +------------------------------------
 4 files changed, 50 insertions(+), 37 deletions(-)
 create mode 100644 lib/util/padd_file.c

diff --git a/include/util.h b/include/util.h
index 8e54cb4..28d21bc 100644
--- a/include/util.h
+++ b/include/util.h
@@ -3,6 +3,7 @@
 #define UTIL_H
 
 #include <sys/types.h>
+#include <stdint.h>
 
 /*
   Removes all preceeding and trailing slashes, shortens all sequences of
@@ -50,4 +51,10 @@ int pushdn(const char *path, size_t len);
 /* Returns 0 on success. On failure, prints error message to stderr. */
 int popd(void);
 
+/*
+  Write zero bytes to an output file to padd it to specified block size.
+  Returns 0 on success. On failure, prints error message to stderr.
+*/
+int padd_file(int outfd, uint64_t size, size_t blocksize);
+
 #endif /* UTIL_H */
diff --git a/lib/Makemodule.am b/lib/Makemodule.am
index ddc78f6..a676291 100644
--- a/lib/Makemodule.am
+++ b/lib/Makemodule.am
@@ -30,7 +30,7 @@ libutil_a_SOURCES = lib/util/canonicalize_name.c lib/util/write_retry.c
 libutil_a_SOURCES += lib/util/read_retry.c include/util.h
 libutil_a_SOURCES += lib/util/print_version.c lib/util/mkdir_p.c
 libutil_a_SOURCES += lib/util/str_table.c include/str_table.h
-libutil_a_SOURCES += lib/util/dirstack.c
+libutil_a_SOURCES += lib/util/dirstack.c lib/util/padd_file.c
 
 if WITH_GZIP
 libcompress_a_SOURCES += lib/comp/gzip.c
diff --git a/lib/util/padd_file.c b/lib/util/padd_file.c
new file mode 100644
index 0000000..8598b8b
--- /dev/null
+++ b/lib/util/padd_file.c
@@ -0,0 +1,41 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later */
+#include "util.h"
+
+#include <stdlib.h>
+#include <stdio.h>
+
+int padd_file(int outfd, uint64_t size, size_t blocksize)
+{
+	size_t padd_sz = size % blocksize;
+	int status = -1;
+	uint8_t *buffer;
+	ssize_t ret;
+
+	if (padd_sz == 0)
+		return 0;
+
+	padd_sz = blocksize - padd_sz;
+
+	buffer = calloc(1, padd_sz);
+	if (buffer == NULL)
+		goto fail_errno;
+
+	ret = write_retry(outfd, buffer, padd_sz);
+
+	if (ret < 0)
+		goto fail_errno;
+
+	if ((size_t)ret < padd_sz)
+		goto fail_trunc;
+
+	status = 0;
+out:
+	free(buffer);
+	return status;
+fail_trunc:
+	fputs("padding output to block size: truncated write\n", stderr);
+	goto out;
+fail_errno:
+	perror("padding output file to block size");
+	goto out;
+}
diff --git a/mkfs/mkfs.c b/mkfs/mkfs.c
index 8317bd2..2219989 100644
--- a/mkfs/mkfs.c
+++ b/mkfs/mkfs.c
@@ -1,41 +1,6 @@
 /* SPDX-License-Identifier: GPL-3.0-or-later */
 #include "mkfs.h"
 
-static int padd_file(int outfd, sqfs_super_t *super, options_t *opt)
-{
-	size_t padd_sz = super->bytes_used % opt->devblksz;
-	uint8_t *buffer;
-	ssize_t ret;
-
-	if (padd_sz == 0)
-		return 0;
-
-	padd_sz = opt->devblksz - padd_sz;
-
-	buffer = calloc(1, padd_sz);
-	if (buffer == NULL) {
-		perror("padding output file to block size");
-		return -1;
-	}
-
-	ret = write_retry(outfd, buffer, padd_sz);
-
-	if (ret < 0) {
-		perror("Error padding squashfs image to page size");
-		free(buffer);
-		return -1;
-	}
-
-	if ((size_t)ret < padd_sz) {
-		fputs("Truncated write trying to padd squashfs image\n",
-		      stderr);
-		return -1;
-	}
-
-	free(buffer);
-	return 0;
-}
-
 static int process_file(data_writer_t *data, tree_node_t *n, bool quiet)
 {
 	int ret, infd;
@@ -198,7 +163,7 @@ int main(int argc, char **argv)
 	if (sqfs_super_write(&super, outfd))
 		goto out_data;
 
-	if (padd_file(outfd, &super, &opt))
+	if (padd_file(outfd, super.bytes_used, opt.devblksz))
 		goto out_data;
 
 	status = EXIT_SUCCESS;
-- 
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