On 1.11.21 г. 11:08, Tzvetomir Stoyanov (VMware) wrote:
In order to be consistent with the other APIs, a new set of kprobe APIs is introduced: tracefs_kprobe_alloc(); tracefs_kretprobe_alloc(); tracefs_kprobe_create(); tracefs_kprobe_destroy(); tracefs_kprobe_free(); These APIs work with kprobe context, represented by the tracefs_dynevent structure. Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@xxxxxxxxx> --- include/tracefs.h | 8 ++ src/tracefs-kprobes.c | 168 ++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 176 insertions(+) diff --git a/include/tracefs.h b/include/tracefs.h index 4e721eb..85185ce 100644 --- a/include/tracefs.h +++ b/include/tracefs.h @@ -247,6 +247,14 @@ enum tracefs_kprobe_type { TRACEFS_KRETPROBE, };+struct tracefs_dynevent *+tracefs_kprobe_alloc(const char *system, const char *event, const char *addr, const char *format); +struct tracefs_dynevent * +tracefs_kretprobe_alloc(const char *system, const char *event, + const char *addr, const char *format, int max); +int tracefs_kprobe_create(struct tracefs_dynevent *kprobe); +int tracefs_kprobe_destroy(struct tracefs_dynevent *kprobe, bool force); +void tracefs_kprobe_free(struct tracefs_dynevent *kprobe); int tracefs_kprobe_raw(const char *system, const char *event, const char *addr, const char *format); int tracefs_kretprobe_raw(const char *system, const char *event, diff --git a/src/tracefs-kprobes.c b/src/tracefs-kprobes.c index d4c5f9e..906f914 100644 --- a/src/tracefs-kprobes.c +++ b/src/tracefs-kprobes.c @@ -20,6 +20,134 @@ #define KPROBE_EVENTS "kprobe_events" #define KPROBE_DEFAULT_GROUP "kprobes"+static struct tracefs_dynevent *+kprobe_alloc(enum trace_dynevent_type type, const char *system, const char *event, + const char *addr, const char *format) +{ + struct tracefs_dynevent *kp; + const char *sys = system; + const char *ename = event; + char *tmp; + + if (!addr) { + errno = EBADMSG; + return NULL; + } + if (!sys) + sys = KPROBE_DEFAULT_GROUP; + + if (!event) { + ename = strdup(addr); + if (!ename) + return NULL; + tmp = strchr(ename, ':'); + if (tmp) + *tmp = '\0'; + } + + kp = dynevent_alloc(type, sys, ename, addr, format); + if (!event) + free((char *)ename); + + return kp; +} + + +/** + * tracefs_kprobe_alloc - Allocate new kprobe context + * @system: The system name (NULL for the default kprobes) + * @event: The event to create (NULL to use @addr for the event) + * @addr: The function and offset (or address) to insert the probe + * @format: The format string to define the probe. + * + * Allocate a kprobe context that will be in the @system group (or kprobes if + * @system is NULL). Have the name of @event (or @addr if @event is + * NULL). Will be inserted to @addr (function name, with or without + * offset, or a address). And the @format will define the format + * of the kprobe. See the Linux documentation file under: + * Documentation/trace/kprobetrace.rst + * The kprobe is not created in the system. + * + * Return a pointer to a kprobe context on success, or NULL on error. + * The returned pointer must be freed with tracefs_kprobe_free() + * + * errno will be set to EBADMSG if addr is NULL. + */ +struct tracefs_dynevent * +tracefs_kprobe_alloc(const char *system, const char *event, const char *addr, const char *format) + +{ + return kprobe_alloc(TRACE_DYNEVENT_KPROBE, system, event, addr, format); +} + +/** + * tracefs_kretprobe_alloc - Allocate new kretprobe context + * @system: The system name (NULL for the default kprobes) + * @event: The event to create (NULL to use @addr for the event) + * @addr: The function and offset (or address) to insert the retprobe + * @format: The format string to define the retprobe. + *
@max is not documented.
+ * Allocate a kretprobe that will be in the @system group (or kprobes if
+ * @system is NULL). Have the name of @event (or @addr if @event is
+ * NULL). Will be inserted to @addr (function name, with or without
+ * offset, or a address). And the @format will define the raw format
+ * of the kprobe. See the Linux documentation file under:
+ * Documentation/trace/kprobetrace.rst
+ * The kretprobe is not created in the system.
+ *
+ * Return a pointer to a kprobe context on success, or NULL on error.
+ * The returned pointer must be freed with tracefs_kprobe_free()
+ *
+ * errno will be set to EBADMSG if addr is NULL.
+ */
+struct tracefs_dynevent *
+tracefs_kretprobe_alloc(const char *system, const char *event,
+ const char *addr, const char *format, int max)
+{
+ struct tracefs_dynevent *kp;
+ int ret;
+
+ kp = kprobe_alloc(TRACE_DYNEVENT_KRETPROBE, system, event, addr, format);
+ if (!kp)
+ return NULL;
+ if (max) {
+ free(kp->prefix);
+ kp->prefix = NULL;
+ ret = asprintf(&kp->prefix, "r%d:", max);
+ if (ret < 0)
+ goto error;
+ }
+
+ return kp;
+error:
+ dynevent_free(kp);
+ return NULL;
+}
+
+/**
+ * tracefs_kprobe_create - Create a kprobe or kretprobe in the system
+ * @kprobe: Pointer to a kprobe context, describing the probe
+ *
+ * Return 0 on success, or -1 on error.
+ */
+int tracefs_kprobe_create(struct tracefs_dynevent *kprobe)
+{
+ return dynevent_create(kprobe);
+}
+
hmm, what will happen if if you have a code like this:
struct tracefs_dynevent *synth = tracefs_synth_alloc(...)
int ret = tracefs_kprobe_create(synth);
Are you just giving several additional fake names to the same function ('dynevent_create()')?
+/**
+ * tracefs_kprobe_free - Free a kprobe context
+ * @kprobe: Pointer to a kprobe context
+ *
+ * The kprobe/kretprobe, described by this context, is not
+ * removed from the system by this API. It only frees the memory.
+ */
+void tracefs_kprobe_free(struct tracefs_dynevent *kprobe)
+{
+ dynevent_free(kprobe);
+}
+
The same argument applys here. Thanks! Yordan
+ static int insert_kprobe(const char *type, const char *system, const char *event, const char *addr, const char *format) @@ -474,3 +602,43 @@ int tracefs_kprobe_clear_probe(const char *system, const char *event, bool forcereturn ret < 0 ? -1 : 0;} + +/** + * tracefs_kprobe_destroy - Remove a kprobe or kretprobe from the system + * @kprobe: A kprobe context, describing the kprobe that will be deleted. + * If NULL, all kprobes and kretprobes in the system will be deleted + * @force: Will attempt to disable all kprobe events and clear them + * + * The kprobe/kretprobe context is not freed by this API. + * It only removes the probe from the system. + * + * Return 0 on success, or -1 on error. + */ +int tracefs_kprobe_destroy(struct tracefs_dynevent *kprobe, bool force) +{ + char **instance_list; + int ret; + + if (!kprobe) { + if (tracefs_instance_file_clear(NULL, KPROBE_EVENTS) == 0) + return 0; + if (!force) + return -1; + /* Attempt to disable all kprobe events */ + return kprobe_clear_probes(NULL, force); + } + + /* + * Since we know we are disabling a specific event, try + * to disable it first before clearing it. + */ + if (force) { + instance_list = tracefs_instances(NULL); + disable_events(kprobe->system, kprobe->event, instance_list); + tracefs_list_free(instance_list); + } + + ret = dynevent_destroy(kprobe); + + return ret < 0 ? -1 : 0; +}
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