[PATCH] copyhandler: allow to set offset for input

[Stefano Babic]

Allow to skip bytes at the beginnning of the source file.

Signed-off-by: Stefano Babic <stefan...@swupdate.org>
---
doc/source/handlers.rst | 3 +++
handlers/copy_handler.c | 31 +++++++++++++++++++++++++++----
2 files changed, 30 insertions(+), 4 deletions(-)

diff --git a/doc/source/handlers.rst b/doc/source/handlers.rst
index d9ac6c7e..6742c10a 100644
--- a/doc/source/handlers.rst
+++ b/doc/source/handlers.rst
@@ -976,6 +976,9 @@ is called twice.
| | | If 0 or not set, the handler will try to find the |
| | | size from the device. |
+-------------+----------+----------------------------------------------------+
+ | offset | string | Value in dec or hex with the offset to be set for |
+ | | | the source file (to copy just a part). |
+ +-------------+----------+----------------------------------------------------+
| chain | string | Handler to be called to install the data read |
| | | from the "copyfrom" source. |
+-------------+----------+----------------------------------------------------+
diff --git a/handlers/copy_handler.c b/handlers/copy_handler.c
index 7716139e..a0cd7714 100644
--- a/handlers/copy_handler.c
+++ b/handlers/copy_handler.c
@@ -60,7 +60,7 @@ char *copyfrom;
struct img_type *base_img;
char *chained_handler;

-static int copy_single_file(const char *path, ssize_t size, struct img_type *img, const char *chained)
+static int copy_single_file(const char *path, off_t skipbytes, ssize_t size, struct img_type *img, const char *chained)
{
int fdout, fdin, ret;
struct stat statbuf;
@@ -89,6 +89,14 @@ static int copy_single_file(const char *path, ssize_t size, struct img_type *img
return -ENODEV;
}

+ if (skipbytes > 0) {
+ if (lseek(fdin, skipbytes, SEEK_SET) < 0) {
+ ERROR("Source offset wrong, accnot be set: 0x%lx", skipbytes);
+ close(fdin);
+ return -EINVAL;
+ }
+ }
+
/*
* try to detect the size if was not set in sw-description
*/
@@ -114,10 +122,16 @@ static int copy_single_file(const char *path, ssize_t size, struct img_type *img
else {
size = -1;
}
+ /*
+ * if size is detected, the offset
+ * must be subtracted.
+ */
+ if (size > 0)
+ size -= skipbytes;
}

if (size < 0) {
- ERROR("Size cannot be detected for %s", path);
+ ERROR("Size cannot be detected for %s or it is before offset 0x%lx", path, skipbytes);
close(fdin);
return -ENODEV;
}
@@ -213,7 +227,7 @@ static int recurse_directory(const char *fpath, const struct stat *sb,
* of steps. So increase it before copying.
*/
swupdate_progress_addstep();
- if (copy_single_file(fpath, 0, &cpyimg, chained_handler))
+ if (copy_single_file(fpath, 0, 0, &cpyimg, chained_handler))
result = FTW_STOP;
}

@@ -229,6 +243,7 @@ static int copy_image_file(struct img_type *img, void *data)
struct dict_list *proplist;
struct dict_list_elem *entry;
size_t size = 0;
+ off_t skipbytes = 0;
struct script_handler_data *script_data;
bool recursive, createdest;

@@ -300,6 +315,14 @@ static int copy_image_file(struct img_type *img, void *data)
WARN("size property %s: ustrtoull failed", tmp);
}

+ /*
+ * Detect the source must be read from an offset
+ */
+ tmp = dict_get_value(&img->properties, "offset");
+ if (tmp) {
+ skipbytes = ustrtoull(tmp, NULL, 0);
+ }
+
/*
* No chain set, fallback to rawcopy
*/
@@ -346,7 +369,7 @@ static int copy_image_file(struct img_type *img, void *data)

} else {
swupdate_progress_addstep();
- ret = copy_single_file(copyfrom, size, img, chained_handler);
+ ret = copy_single_file(copyfrom, skipbytes, size, img, chained_handler);
}
}

--
2.43.0