From 62823da1bd46f24e2b498513a809011dfe16cd9b Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (VMware)" Date: Tue, 8 Jun 2021 17:27:44 -0400 Subject: [PATCH] libtraceevent: Handle parsing of "(REC)->" case If a trace event wraps the special __entry variable to dereference it with parenthesis, it shows up in the trace event format file wrapping the "(REC)" as well. For example, the "func_repeats" event passed the __entry into a helper macro in the TP_printk() portion, and the macro correctly wrapped its parameter in parenthesis. This caused the output to show: "(((u64)(REC)->top_delta_ts << 32) | (REC)->bottom_delta_ts)" The parser then failed to parse the "(REC)->" portion, as it expected the "->" to appear directly after the "REC". This is not a requirement, and the parser should be able to handle such cases. When this occurred, trace-cmd would error with the following message: trace-cmd: No such file or directory Error: expected type 4 but read 5 Link: https://lore.kernel.org/linux-trace-devel/20210608172744.796e93b7@gandalf.local.home Fixes: 6582b0a ("tools/events: Add files to create libtraceevent.a") Reported-by: Julia Lawall Signed-off-by: Steven Rostedt (VMware) --- src/event-parse.c | 27 ++++++++++++++++++++++++--- 1 file changed, 24 insertions(+), 3 deletions(-) diff --git a/src/event-parse.c b/src/event-parse.c index 97c1a97..1217491 100644 --- a/src/event-parse.c +++ b/src/event-parse.c @@ -2311,8 +2311,19 @@ process_entry(struct tep_event *event __maybe_unused, struct tep_print_arg *arg, char *field; char *token; - if (read_expected(TEP_EVENT_OP, "->") < 0) - goto out_err; + type = read_token_item(&token); + /* + * Check if REC happens to be surrounded by parenthesis, and + * return if that's the case, as "(REC)->" is valid. + * but return TEP_EVENT_ITEM. + */ + if (type == TEP_EVENT_DELIM && strcmp(token, ")") == 0) { + *tok = token; + return TEP_EVENT_ITEM; + } + + if (test_type_token(type, token, TEP_EVENT_OP, "->")) + goto out_free; if (read_expect_type(TEP_EVENT_ITEM, &token) < 0) goto out_free; @@ -2338,7 +2349,6 @@ process_entry(struct tep_event *event __maybe_unused, struct tep_print_arg *arg, out_free: free_token(token); - out_err: *tok = NULL; return TEP_EVENT_ERROR; } @@ -3033,6 +3043,17 @@ process_paren(struct tep_event *event, struct tep_print_arg *arg, char **tok) if (type == TEP_EVENT_ERROR) goto out_free; + /* + * If REC is surrounded by parenthesis, the process_arg() + * will return TEP_EVENT_ITEM with token == ")". In + * this case, we need to continue processing the item + * and return. + */ + if (type == TEP_EVENT_ITEM && strcmp(token, ")") == 0) { + free_token(token); + return process_entry(event, arg, tok); + } + if (test_type_token(type, token, TEP_EVENT_DELIM, ")")) goto out_free; -- 2.31.1