Hi Ye,
On Thu, 25 Jan 2024 15:39:16 +0800
Ye Bin <yebin10@huawei.com> wrote:
> Add traceprobe_expand_dentry_args() to expand dentry args. this API is
> prepare to support "%pd" print format for kprobe.
>
> Signed-off-by: Ye Bin <yebin10@huawei.com>
> ---
> kernel/trace/trace_probe.c | 50 ++++++++++++++++++++++++++++++++++++++
> kernel/trace/trace_probe.h | 2 ++
> 2 files changed, 52 insertions(+)
>
> diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c
> index 4dc74d73fc1d..0c1caf0f474a 100644
> --- a/kernel/trace/trace_probe.c
> +++ b/kernel/trace/trace_probe.c
> @@ -1565,6 +1565,56 @@ const char **traceprobe_expand_meta_args(int argc, const char *argv[],
> return ERR_PTR(ret);
> }
>
> +/* @buf: *buf must be equal to NULL. Caller must to free *buf */
> +int traceprobe_expand_dentry_args(int argc, const char *argv[], char **buf)
> +{
> + int i, used, ret;
> + int bufsize = MAX_DENTRY_ARGS_LEN;
nit: this bufsize is consistent, thus you should use the MAX_DENTRY_ARGS_LEN
directly. (or add 'const' or maybe you can update bufsize as remaining size)
Thanks,
> + char *tmpbuf = NULL;
> +
> + if (*buf)
> + return -EINVAL;
> +
> + used = 0;
> + for (i = 0; i < argc; i++) {
> + if (glob_match("*:%pd", argv[i])) {
> + char *tmp;
> + char *equal;
> +
> + if (!tmpbuf) {
> + tmpbuf = kmalloc(bufsize, GFP_KERNEL);
> + if (!tmpbuf)
> + return -ENOMEM;
> + }
> +
> + tmp = kstrdup(argv[i], GFP_KERNEL);
> + if (!tmp)
> + goto nomem;
> +
> + equal = strchr(tmp, '=');
> + if (equal)
> + *equal = '\0';
> + tmp[strlen(argv[i]) - 4] = '\0';
> + ret = snprintf(tmpbuf + used, bufsize - used,
> + "%s%s+0x0(+0x%zx(%s)):string",
> + equal ? tmp : "", equal ? "=" : "",
> + offsetof(struct dentry, d_name.name),
> + equal ? equal + 1 : tmp);
> + kfree(tmp);
> + if (ret >= bufsize - used)
> + goto nomem;
> + argv[i] = tmpbuf + used;
> + used += ret + 1;
> + }
> + }
> +
> + *buf = tmpbuf;
> + return 0;
> +nomem:
> + kfree(tmpbuf);
> + return -ENOMEM;
> +}
> +
> void traceprobe_finish_parse(struct traceprobe_parse_context *ctx)
> {
> clear_btf_context(ctx);
> diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h
> index 850d9ecb6765..5800513439f3 100644
> --- a/kernel/trace/trace_probe.h
> +++ b/kernel/trace/trace_probe.h
> @@ -34,6 +34,7 @@
> #define MAX_ARRAY_LEN 64
> #define MAX_ARG_NAME_LEN 32
> #define MAX_BTF_ARGS_LEN 128
> +#define MAX_DENTRY_ARGS_LEN 256
> #define MAX_STRING_SIZE PATH_MAX
> #define MAX_ARG_BUF_LEN (MAX_TRACE_ARGS * MAX_ARG_NAME_LEN)
>
> @@ -402,6 +403,7 @@ extern int traceprobe_parse_probe_arg(struct trace_probe *tp, int i,
> const char **traceprobe_expand_meta_args(int argc, const char *argv[],
> int *new_argc, char *buf, int bufsize,
> struct traceprobe_parse_context *ctx);
> +extern int traceprobe_expand_dentry_args(int argc, const char *argv[], char **buf);
>
> extern int traceprobe_update_arg(struct probe_arg *arg);
> extern void traceprobe_free_probe_arg(struct probe_arg *arg);
> --
> 2.31.1
>
--
Masami Hiramatsu (Google) <mhiramat@kernel.org>