Add --offset to erofsfuse to skip bytes at the start of the image file.
Signed-off-by: Li He <[email protected]>
---
We should add offset to fuse_operations so erofsfuse can parse it from
command line. fuse_opt_parse can not parse cfg directly.
Changes since v0
+ Add manpage for erofsfuse offset option
fuse/main.c | 6 ++++++
include/erofs/config.h | 3 +++
lib/io.c | 2 ++
man/erofsfuse.1 | 3 +++
4 files changed, 14 insertions(+)
diff --git a/fuse/main.c b/fuse/main.c
index f4c2476..a2a6449 100644
--- a/fuse/main.c
+++ b/fuse/main.c
@@ -151,6 +151,7 @@ static struct fuse_operations erofs_ops = {
static struct options {
const char *disk;
const char *mountpoint;
+ u64 offset;
unsigned int debug_lvl;
bool show_help;
bool odebug;
@@ -158,6 +159,7 @@ static struct options {
#define OPTION(t, p) { t, offsetof(struct options, p), 1 }
static const struct fuse_opt option_spec[] = {
+ OPTION("--offset=%lu", offset),
OPTION("--dbglevel=%u", debug_lvl),
OPTION("--help", show_help),
FUSE_OPT_KEY("--device=", 1),
@@ -170,6 +172,7 @@ static void usage(void)
fputs("usage: [options] IMAGE MOUNTPOINT\n\n"
"Options:\n"
+ " --offset=# # bytes to skip when read IMAGE\n"
" --dbglevel=# set output message level to #
(maximum 9)\n"
" --device=# specify an extra device to be used
together\n"
#if FUSE_MAJOR_VERSION < 3
@@ -190,6 +193,7 @@ static void usage(void)
static void erofsfuse_dumpcfg(void)
{
erofs_dump("disk: %s\n", fusecfg.disk);
+ erofs_dump("offset: %lu\n", fusecfg.offset);
erofs_dump("mountpoint: %s\n", fusecfg.mountpoint);
erofs_dump("dbglevel: %u\n", cfg.c_dbg_lvl);
}
@@ -279,6 +283,8 @@ int main(int argc, char *argv[])
if (fusecfg.odebug && cfg.c_dbg_lvl < EROFS_DBG)
cfg.c_dbg_lvl = EROFS_DBG;
+ cfg.c_offset = fusecfg.offset;
+
erofsfuse_dumpcfg();
ret = dev_open_ro(fusecfg.disk);
if (ret) {
diff --git a/include/erofs/config.h b/include/erofs/config.h
index 0d0916c..8b6f7db 100644
--- a/include/erofs/config.h
+++ b/include/erofs/config.h
@@ -73,6 +73,9 @@ struct erofs_configure {
char *fs_config_file;
char *block_list_file;
#endif
+
+ /* offset when read mutli partiton image */
+ u64 c_offset;
};
extern struct erofs_configure cfg;
diff --git a/lib/io.c b/lib/io.c
index 9c663c5..524cfb4 100644
--- a/lib/io.c
+++ b/lib/io.c
@@ -261,6 +261,8 @@ int dev_read(int device_id, void *buf, u64 offset, size_t
len)
if (cfg.c_dry_run)
return 0;
+ offset += cfg.c_offset;
+
if (!buf) {
erofs_err("buf is NULL");
return -EINVAL;
diff --git a/man/erofsfuse.1 b/man/erofsfuse.1
index 9db6827..1d47163 100644
--- a/man/erofsfuse.1
+++ b/man/erofsfuse.1
@@ -26,6 +26,9 @@ warning messages.
.BI "\-\-device=" path
Specify an extra device to be used together.
You may give multiple `--device' options in the correct order.
+.TP
+.BI "\-\-offset=" #
+Specify offset bytes to skip when read image file. The default is 0.
.SS "FUSE options:"
.TP
\fB-d -o\fR debug
--
2.20.1
