The actions_parse() function uses open-coded logic to extract arguments from a string. This includes manual length checks and strncmp() calls, which can be verbose and error-prone.
To simplify and improve the robustness of argument parsing, introduce a new extract_arg() helper macro. This macro extracts the value from a "key=value" pair, making the code more concise and readable. Also, introduce STRING_LENGTH() and strncmp_static() macros to perform compile-time calculations of string lengths and safer string comparisons. Refactor actions_parse() to use these new helpers, resulting in cleaner and more maintainable code. Signed-off-by: Wander Lairson Costa <[email protected]> --- tools/tracing/rtla/src/actions.c | 57 +++++++++++++++++++++++--------- tools/tracing/rtla/src/utils.h | 14 ++++++-- 2 files changed, 54 insertions(+), 17 deletions(-) diff --git a/tools/tracing/rtla/src/actions.c b/tools/tracing/rtla/src/actions.c index e933c2c68b208..b50bf9f9adf28 100644 --- a/tools/tracing/rtla/src/actions.c +++ b/tools/tracing/rtla/src/actions.c @@ -113,6 +113,29 @@ actions_add_continue(struct actions *self) action->type = ACTION_CONTINUE; } +static inline const char *__extract_arg(const char *token, const char *opt, size_t opt_len) +{ + const size_t tok_len = strlen(token); + + if (tok_len <= opt_len) + return NULL; + + if (strncmp(token, opt, opt_len)) + return NULL; + + return token + opt_len; +} + +/* + * extract_arg - extract argument value from option token + * @token: option token (e.g., "file=trace.txt") + * @opt: option name to match (e.g., "file") + * + * Returns pointer to argument value after "=" if token matches "opt=", + * otherwise returns NULL. + */ +#define extract_arg(token, opt) __extract_arg(token, opt "=", STRING_LENGTH(opt "=")) + /* * actions_parse - add an action based on text specification */ @@ -122,6 +145,7 @@ actions_parse(struct actions *self, const char *trigger, const char *tracefn) enum action_type type = ACTION_NONE; const char *token; char trigger_c[strlen(trigger) + 1]; + const char *arg_value; /* For ACTION_SIGNAL */ int signal = 0, pid = 0; @@ -152,12 +176,10 @@ actions_parse(struct actions *self, const char *trigger, const char *tracefn) if (token == NULL) trace_output = tracefn; else { - if (strlen(token) > 5 && strncmp(token, "file=", 5) == 0) { - trace_output = token + 5; - } else { + trace_output = extract_arg(token, "file"); + if (!trace_output) /* Invalid argument */ return -1; - } token = strtok(NULL, ","); if (token != NULL) @@ -169,17 +191,21 @@ actions_parse(struct actions *self, const char *trigger, const char *tracefn) case ACTION_SIGNAL: /* Takes two arguments, num (signal) and pid */ while (token != NULL) { - if (strlen(token) > 4 && strncmp(token, "num=", 4) == 0) { - if (strtoi(token + 4, &signal)) - return -1; - } else if (strlen(token) > 4 && strncmp(token, "pid=", 4) == 0) { - if (strncmp(token + 4, "parent", 7) == 0) - pid = -1; - else if (strtoi(token + 4, &pid)) + arg_value = extract_arg(token, "num"); + if (arg_value) { + if (strtoi(arg_value, &signal)) return -1; } else { - /* Invalid argument */ - return -1; + arg_value = extract_arg(token, "pid"); + if (arg_value) { + if (strncmp_static(arg_value, "parent") == 0) + pid = -1; + else if (strtoi(arg_value, &pid)) + return -1; + } else { + /* Invalid argument */ + return -1; + } } token = strtok(NULL, ","); @@ -194,9 +220,10 @@ actions_parse(struct actions *self, const char *trigger, const char *tracefn) case ACTION_SHELL: if (token == NULL) return -1; - if (strlen(token) > 8 && strncmp(token, "command=", 8)) + arg_value = extract_arg(token, "command"); + if (!arg_value) return -1; - actions_add_shell(self, token + 8); + actions_add_shell(self, arg_value); break; case ACTION_CONTINUE: /* Takes no argument */ diff --git a/tools/tracing/rtla/src/utils.h b/tools/tracing/rtla/src/utils.h index efbf798650306..7fa3ac5e0bfb6 100644 --- a/tools/tracing/rtla/src/utils.h +++ b/tools/tracing/rtla/src/utils.h @@ -13,8 +13,18 @@ #define MAX_NICE 20 #define MIN_NICE -19 -#define container_of(ptr, type, member)({ \ - const typeof(((type *)0)->member) *__mptr = (ptr); \ +#ifndef ARRAY_SIZE +#define ARRAY_SIZE(x) (sizeof(x) / sizeof(*(x))) +#endif + +/* Calculate string length at compile time (excluding null terminator) */ +#define STRING_LENGTH(s) (ARRAY_SIZE(s) - sizeof(*(s))) + +/* Compare string with static string, length determined at compile time */ +#define strncmp_static(s1, s2) strncmp(s1, s2, STRING_LENGTH(s2)) + +#define container_of(ptr, type, member)({ \ + const typeof(((type *)0)->member) * __mptr = (ptr); \ (type *)((char *)__mptr - offsetof(type, member)) ; }) extern int config_debug; -- 2.52.0
