| Message ID | 20230109033213.3220884-1-quanfafu@gmail.com (mailing list archive) |
|---|---|
| State | Changes Requested |
| Headers | show |
| Series | [v2] tracing/eprobe: Replace snprintf with memcpy | expand |
On Mon, 9 Jan 2023 11:32:13 +0800 Quanfa Fu <quanfafu@gmail.com> wrote: > @@ -923,17 +923,17 @@ static int trace_eprobe_parse_filter(struct trace_eprobe *ep, int argc, const ch > > p = ep->filter_str; > for (i = 0; i < argc; i++) { > - ret = snprintf(p, len, "%s ", argv[i]); > - if (ret < 0) > - goto error; > - if (ret > len) { > - ret = -E2BIG; > - goto error; > - } > - p += ret; > - len -= ret; > + arg_len = strlen(argv[i]); > + memcpy((void *)p, argv[i], arg_len); > + > + if (i == argc - 1) > + p[arg_len] = '\0'; > + else > + p[arg_len] = ' '; > + > + p += arg_len + 1; > + len -= arg_len + 1; > } The above is too complex. I mentioned strncat() but you could still just keep snprintf() too, which adds the '\0'; for (i = 0; i < argc; i++) { if (i) ret = snprintf(p, len, " %s", argv[i]); else ret = snprintf(p, len, "%s", argv[i]); p += ret; len -= ret; } -- Steve > - p[-1] = '\0'; > > /* > * Ensure the filter string can be parsed correctly. Note, this
Thanks, I'll check it out. Thanks !! On Mon, Jan 9, 2023 at 11:52 AM Steven Rostedt <rostedt@goodmis.org> wrote: > > On Mon, 9 Jan 2023 11:32:13 +0800 > Quanfa Fu <quanfafu@gmail.com> wrote: > > > @@ -923,17 +923,17 @@ static int trace_eprobe_parse_filter(struct trace_eprobe *ep, int argc, const ch > > > > p = ep->filter_str; > > for (i = 0; i < argc; i++) { > > - ret = snprintf(p, len, "%s ", argv[i]); > > - if (ret < 0) > > - goto error; > > - if (ret > len) { > > - ret = -E2BIG; > > - goto error; > > - } > > - p += ret; > > - len -= ret; > > + arg_len = strlen(argv[i]); > > + memcpy((void *)p, argv[i], arg_len); > > + > > + if (i == argc - 1) > > + p[arg_len] = '\0'; > > + else > > + p[arg_len] = ' '; > > + > > + p += arg_len + 1; > > + len -= arg_len + 1; > > } > > The above is too complex. I mentioned strncat() but you could still > just keep snprintf() too, which adds the '\0'; > > for (i = 0; i < argc; i++) { > if (i) > ret = snprintf(p, len, " %s", argv[i]); > else > ret = snprintf(p, len, "%s", argv[i]); > p += ret; > len -= ret; > } > > -- Steve > > > - p[-1] = '\0'; > > > > /* > > * Ensure the filter string can be parsed correctly. Note, this
diff --git a/kernel/trace/trace_eprobe.c b/kernel/trace/trace_eprobe.c index 352b65e2b910..56eb39f495f6 100644 --- a/kernel/trace/trace_eprobe.c +++ b/kernel/trace/trace_eprobe.c @@ -905,7 +905,7 @@ static int trace_eprobe_tp_update_arg(struct trace_eprobe *ep, const char *argv[ static int trace_eprobe_parse_filter(struct trace_eprobe *ep, int argc, const char *argv[]) { struct event_filter *dummy = NULL; - int i, ret, len = 0; + int i, ret, arg_len, len = 0; char *p; if (argc == 0) { @@ -923,17 +923,17 @@ static int trace_eprobe_parse_filter(struct trace_eprobe *ep, int argc, const ch p = ep->filter_str; for (i = 0; i < argc; i++) { - ret = snprintf(p, len, "%s ", argv[i]); - if (ret < 0) - goto error; - if (ret > len) { - ret = -E2BIG; - goto error; - } - p += ret; - len -= ret; + arg_len = strlen(argv[i]); + memcpy((void *)p, argv[i], arg_len); + + if (i == argc - 1) + p[arg_len] = '\0'; + else + p[arg_len] = ' '; + + p += arg_len + 1; + len -= arg_len + 1; } - p[-1] = '\0'; /* * Ensure the filter string can be parsed correctly. Note, this
No need to check for negative return value from snprintf() as the code does not return negative values. Replace snprintf with memcpy. Signed-off-by: Quanfa Fu <quanfafu@gmail.com> ----- V1 -> V2: memory allc uses kzalloc and replace snprintf with memcpy --- kernel/trace/trace_eprobe.c | 22 +++++++++++----------- 1 file changed, 11 insertions(+), 11 deletions(-)