On Sun, 3 Apr 2022 15:24:33 +0000
Joel Fernandes <joel@xxxxxxxxxxxxxxxxx> wrote:
> Something like the following seems to work, and the file grows to only 4KB.
> Note with memfd, the file name does not have to be unique and the fd entry
> in the process denotes the file's uniqueness.
>
> I'll roll it into a patch, let me know if you disagree:
I'm OK with this, but I would really like a "Reviewed-by" from Tzvetomir.
Go ahead and send a real patch.
Thanks,
-- Steve
>
> ---8<---
>
> diff --git a/lib/trace-cmd/include/private/trace-cmd-private.h b/lib/trace-cmd/include/private/trace-cmd-private.h
> index 6934376..3aee139 100644
> --- a/lib/trace-cmd/include/private/trace-cmd-private.h
> +++ b/lib/trace-cmd/include/private/trace-cmd-private.h
> @@ -377,7 +377,6 @@ enum tracecmd_msg_flags {
> };
>
> /* for both client and server */
> -#define MSG_CACHE_FILE "/tmp/trace_msg_cacheXXXXXX"
> struct tracecmd_msg_handle {
> int fd;
> short cpu_count;
> @@ -386,7 +385,6 @@ struct tracecmd_msg_handle {
> bool done;
> bool cache;
> int cfd;
> - char cfile[sizeof(MSG_CACHE_FILE)];
> };
>
> struct tracecmd_tsync_protos {
> diff --git a/lib/trace-cmd/trace-msg.c b/lib/trace-cmd/trace-msg.c
> index 03b853e..1472f20 100644
> --- a/lib/trace-cmd/trace-msg.c
> +++ b/lib/trace-cmd/trace-msg.c
> @@ -593,11 +593,9 @@ tracecmd_msg_handle_alloc(int fd, unsigned long flags)
> int tracecmd_msg_handle_cache(struct tracecmd_msg_handle *msg_handle)
> {
> if (msg_handle->cfd < 0) {
> - strcpy(msg_handle->cfile, MSG_CACHE_FILE);
> - msg_handle->cfd = mkstemp(msg_handle->cfile);
> + msg_handle->cfd = memfd_create("trace_msg_cache", 0);
> if (msg_handle->cfd < 0)
> return -1;
> - unlink(msg_handle->cfile);
> }
> msg_handle->cache = true;
> return 0;
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