| Message ID | 20211103154417.246999-4-tz.stoyanov@gmail.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | libtracefs dynamic events support | expand |
On Wed, 3 Nov 2021 17:44:09 +0200 "Tzvetomir Stoyanov (VMware)" <tz.stoyanov@gmail.com> wrote: > In order to be consistent with the other APIs, new APIs for kprobe > allocation are introduced: > tracefs_kprobe_alloc(); > tracefs_kretprobe_alloc(); > These APIs allocate new kpobe dynamic event, that can be used with > tracefs_dynevent_... set of APIs. > > Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com> > --- > include/tracefs.h | 5 ++ > src/tracefs-kprobes.c | 105 ++++++++++++++++++++++++++++++++++++++++++ > 2 files changed, 110 insertions(+) > > diff --git a/include/tracefs.h b/include/tracefs.h > index 470234d..b8f7c09 100644 > --- a/include/tracefs.h > +++ b/include/tracefs.h > @@ -267,6 +267,11 @@ 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_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 6fdd8f9..d1279ff 100644 > --- a/src/tracefs-kprobes.c > +++ b/src/tracefs-kprobes.c > @@ -20,6 +20,111 @@ > #define KPROBE_EVENTS "kprobe_events" > #define KPROBE_DEFAULT_GROUP "kprobes" > > +static struct tracefs_dynevent * > +kprobe_alloc(enum tracefs_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 > + * @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. Small nit, but what do you have your margins set to? When I set mine to 79 (where 80 is good enough), I get the following for the above text: * 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. * I also added some spaces for clarity. > + * > + * Return a pointer to a kprobe context on success, or NULL on error. > + * The returned pointer must be freed with tracefs_dynevent_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(TRACEFS_DYNEVENT_KPROBE, system, event, addr, format); > +} > + > +/** > + * tracefs_kretprobe_alloc - Allocate new kretprobe > + * @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: Maximum number of instances of the specified function that > + * can be probed simultaneously, or 0 for the default value. > + * > + * 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_dynevent_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(TRACEFS_DYNEVENT_KRETPROBE, system, event, addr, format); > + if (!kp) > + return NULL; > + if (max) { Could add: if (!max) return kp; And then remove the rest of the indentation. -- Steve > + free(kp->prefix); > + kp->prefix = NULL; > + ret = asprintf(&kp->prefix, "r%d:", max); > + if (ret < 0) > + goto error; > + } > + > + return kp; > +error: > + tracefs_dynevent_free(kp); > + return NULL; > +} > + > static int insert_kprobe(const char *type, const char *system, > const char *event, const char *addr, > const char *format)
diff --git a/include/tracefs.h b/include/tracefs.h index 470234d..b8f7c09 100644 --- a/include/tracefs.h +++ b/include/tracefs.h @@ -267,6 +267,11 @@ 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_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 6fdd8f9..d1279ff 100644 --- a/src/tracefs-kprobes.c +++ b/src/tracefs-kprobes.c @@ -20,6 +20,111 @@ #define KPROBE_EVENTS "kprobe_events" #define KPROBE_DEFAULT_GROUP "kprobes" +static struct tracefs_dynevent * +kprobe_alloc(enum tracefs_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 + * @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_dynevent_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(TRACEFS_DYNEVENT_KPROBE, system, event, addr, format); +} + +/** + * tracefs_kretprobe_alloc - Allocate new kretprobe + * @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: Maximum number of instances of the specified function that + * can be probed simultaneously, or 0 for the default value. + * + * 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_dynevent_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(TRACEFS_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: + tracefs_dynevent_free(kp); + return NULL; +} + static int insert_kprobe(const char *type, const char *system, const char *event, const char *addr, const char *format)
In order to be consistent with the other APIs, new APIs for kprobe allocation are introduced: tracefs_kprobe_alloc(); tracefs_kretprobe_alloc(); These APIs allocate new kpobe dynamic event, that can be used with tracefs_dynevent_... set of APIs. Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com> --- include/tracefs.h | 5 ++ src/tracefs-kprobes.c | 105 ++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 110 insertions(+)