bpftool: fix batch file handling issues - #8684
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map_dump() closes the map fd in its error path, and do_dump() then closes the same fd again after a successful dump. Closing an already closed fd leaves errno set to EBADF, which poisons later errno checks such as the batch file read check in do_batch(). Let do_dump() own the fd and remove the close from map_dump(). The same double-close pattern exists in do_show_subset(): both show_map_close_json() and show_map_close_plain() already close the fd, so drop the extra close() there as well. Also propagate the error when bpf_map_get_info_by_fd() fails on a subsequent map in do_dump(): set err = -1 before breaking out of the loop, so a later failure is not silently hidden after an earlier iteration succeeded. Fixes: 99f9863 ("bpftool: Match maps by name") Signed-off-by: Yuan Chen <chenyuan@kylinos.cn>
do_batch() checks errno after the read loop to detect read failures, but fgets() does not clear errno on success, so a stale errno left by a previously executed command (e.g. map dump's EBADF from a double close) makes bpftool report a batch file read failure and exit with an error even though every command succeeded. Use ferror() instead, and track the too-long-line case explicitly. Since do_batch() no longer inspects errno to detect read failures, drop the USE_LIBCAP errno reset in main() that existed only to keep errno clean for the batch mode. Fixes: 71bb428 ("tools: bpf: add bpftool") Signed-off-by: Yuan Chen <chenyuan@kylinos.cn>
do_batch() strips trailing comments by truncating the line at '#' before checking whether fgets() filled the buffer. If a batch line longer than the buffer contains a '#' within the first sizeof(buf) - 1 bytes, the truncation makes strlen(buf) smaller and the line-length check is bypassed. The unread remainder of the line then stays in the file stream and is parsed and executed as a separate command on the next loop iteration. Continuation lines handled below are affected the same way: an overlong continuation line containing '#' bypasses the "command is too long" check, and its unread remainder is executed as a separate command. Detect the truncated read before stripping the comment, using memchr() to look for a newline (instead of strlen(), which is also fooled by an embedded NUL byte) and feof() to tell an overlong line apart from a final line without a trailing newline. A line that fills the buffer exactly (the byte after the read is a newline) is not treated as truncated, so valid maximal-length lines are no longer rejected. Use the result for the line-length checks, so overlong lines are rejected regardless of comments or NUL bytes. Fixes: 71bb428 ("tools: bpf: add bpftool") Signed-off-by: Yuan Chen <chenyuan@kylinos.cn>
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Pull request for series with
subject: bpftool: fix batch file handling issues
version: 5
url: https://patchwork.kernel.org/project/netdevbpf/list/?series=1143455