This patch adds a new '--cat' flag to the 'dump.erofs' command. When
used it will write to the standard output the content of the file
indicated by the '--path' or '--nid' options. For example, if there is a
'/mydir/myfile.txt' file containg the text 'mytext':
$ dump.erofs --cat --path=/mydir/myfile.txt myimage.erofs
mytext
Signed-off-by: Juan Hernandez <jhern...@redhat.com>
---
dump/main.c | 72 ++++++++++++++++++++++++++++++++++++++++++++++++
man/dump.erofs.1 | 13 +++++++--
2 files changed, 83 insertions(+), 2 deletions(-)
diff --git a/dump/main.c b/dump/main.c
index 372162e..ed8d44d 100644
--- a/dump/main.c
+++ b/dump/main.c
@@ -26,6 +26,7 @@ struct erofsdump_cfg {
bool show_superblock;
bool show_statistics;
bool show_subdirectories;
+ bool show_file_content;
erofs_nid_t nid;
const char *inode_path;
};
@@ -80,6 +81,7 @@ static struct option long_options[] = {
{"path", required_argument, NULL, 4},
{"ls", no_argument, NULL, 5},
{"offset", required_argument, NULL, 6},
+ {"cat", no_argument, NULL, 7},
{0, 0, 0, 0},
};
@@ -123,6 +125,7 @@ static void usage(int argc, char **argv)
" -s show information about superblock\n"
" --device=X specify an extra device to be used together\n"
" --ls show directory contents (INODE required)\n"
+ " --cat show file contents (INODE required)\n"
" --nid=# show the target inode info of nid #\n"
" --offset=# skip # bytes at the beginning of IMAGE\n"
" --path=X show the target inode info of path X\n",
@@ -186,6 +189,9 @@ static int erofsdump_parse_options_cfg(int argc, char
**argv)
return -EINVAL;
}
break;
+ case 7:
+ dumpcfg.show_file_content = true;
+ break;
default:
return -EINVAL;
}
@@ -672,6 +678,63 @@ static void erofsdump_show_superblock(void)
uuid_str);
}
+static void erofsdump_show_file_content(void)
+{
+ int err;
+ struct erofs_inode inode = { .sbi = &g_sbi, .nid = dumpcfg.nid };
+ size_t buffer_size;
+ char *buffer_ptr;
+ erofs_off_t pending_size;
+ erofs_off_t read_offset;
+ erofs_off_t read_size;
+
+ if (dumpcfg.inode_path) {
+ err = erofs_ilookup(dumpcfg.inode_path, &inode);
+ if (err) {
+ erofs_err("read inode failed @ %s", dumpcfg.inode_path);
+ return;
+ }
+ } else {
+ err = erofs_read_inode_from_disk(&inode);
+ if (err) {
+ erofs_err("read inode failed @ nid %llu", inode.nid |
0ULL);
+ return;
+ }
+ }
+
+ if (!S_ISREG(inode.i_mode)) {
+ erofs_err("not a regular file @ nid %llu", inode.nid | 0ULL);
+ return;
+ }
+
+ buffer_size = erofs_blksiz(inode.sbi);
+ buffer_ptr = malloc(buffer_size);
+ if (!buffer_ptr) {
+ erofs_err("buffer allocation failed @ nid %llu", inode.nid |
0ULL);
+ return;
+ }
+
+ pending_size = inode.i_size;
+ read_offset = 0;
+ while (pending_size > 0) {
+ read_size = pending_size > buffer_size? buffer_size:
pending_size;
+ err = erofs_pread(&inode, buffer_ptr, read_size, read_offset);
+ if (err) {
+ erofs_err("read file failed @ nid %llu", inode.nid |
0ULL);
+ goto out;
+ }
+ pending_size -= read_size;
+ read_offset += read_size;
+ fwrite(buffer_ptr, read_size, 1, stdout);
+ }
+ fflush(stdout);
+
+out:
+ free(buffer_ptr);
+}
+
+
+
int main(int argc, char **argv)
{
int err;
@@ -696,6 +759,15 @@ int main(int argc, char **argv)
goto exit_dev_close;
}
+ if (dumpcfg.show_file_content) {
+ if (dumpcfg.show_superblock || dumpcfg.show_statistics ||
dumpcfg.show_subdirectories) {
+ fprintf(stderr, "The '--cat' flag is incompatible with
'-S', '-e', '-s' and '--ls'.\n");
+ goto exit_dev_close;
+ }
+ erofsdump_show_file_content();
+ goto exit_dev_close;
+ }
+
if (!dumpcfg.totalshow) {
dumpcfg.show_superblock = true;
dumpcfg.totalshow = 1;
diff --git a/man/dump.erofs.1 b/man/dump.erofs.1
index 6237ead..ec823ec 100644
--- a/man/dump.erofs.1
+++ b/man/dump.erofs.1
@@ -8,7 +8,7 @@ or overall disk statistics information from an EROFS-formatted
image.
\fBdump.erofs\fR [\fIOPTIONS\fR] \fIIMAGE\fR
.SH DESCRIPTION
.B dump.erofs
-is used to retrieve erofs metadata from \fIIMAGE\fP and demonstrate
+is used to retrieve erofs metadata and data from \fIIMAGE\fP and demonstrate
.br
1) overall disk statistics,
.br
@@ -16,7 +16,9 @@ is used to retrieve erofs metadata from \fIIMAGE\fP and
demonstrate
.br
3) file information of the given inode NID,
.br
-4) file extent information of the given inode NID.
+4) file extent information of the given inode NID,
+.br
+5) file content for the given inode NID.
.SH OPTIONS
.TP
.BI "\-\-device=" path
@@ -32,6 +34,13 @@ or
.I path
required.
.TP
+.BI "\-\-cat"
+Write file content to standard output.
+.I NID
+or
+.I path
+required.
+.TP
.BI "\-\-nid=" NID
Specify an inode NID in order to print its file information.
.TP
--
2.47.1
