From 0a398bc4ce5e8f150e71cc7196162e677d571821 Mon Sep 17 00:00:00 2001 From: Francis Deslauriers Date: Wed, 22 Jan 2020 11:15:10 -0500 Subject: [PATCH] userspace-probe: Decouple `userspace_probe_add_callsite()` from event and session MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Currently this function takes event and session pointers: - The event is used to get the location type of the probe, - the session is used to get the uid and gid of the user to used them with the `run_as_*()` functions. With the incoming trigger support, we want to reuse this function to add trigger userspace-probe callsites. This commit extracts what will be common in both event and trigger implementations by creating a specialized `userspace_probe_event_add_callsite()` function that uses a generalized `userspace_probe_add_callsite()`. Signed-off-by: Francis Deslauriers Signed-off-by: Jérémie Galarneau Change-Id: Ia3b90050a7bd227a30af0c11395dcdf5aca13583 Depends-on: lttng-ust: I5a800fc92e588c2a6a0e26282b0ad5f31c044479 --- src/bin/lttng-sessiond/kernel.c | 77 ++++++++++++++++++++------------- 1 file changed, 47 insertions(+), 30 deletions(-) diff --git a/src/bin/lttng-sessiond/kernel.c b/src/bin/lttng-sessiond/kernel.c index d93478edf..1fc36e33e 100644 --- a/src/bin/lttng-sessiond/kernel.c +++ b/src/bin/lttng-sessiond/kernel.c @@ -230,7 +230,7 @@ error: static int extract_userspace_probe_offset_function_elf( const struct lttng_userspace_probe_location *probe_location, - struct ltt_kernel_session *session, uint64_t *offset) + uid_t uid, gid_t gid, uint64_t *offset) { int fd; int ret = 0; @@ -267,8 +267,7 @@ int extract_userspace_probe_offset_function_elf( goto end; } - ret = run_as_extract_elf_symbol_offset(fd, symbol, session->uid, - session->gid, offset); + ret = run_as_extract_elf_symbol_offset(fd, symbol, uid, gid, offset); if (ret < 0) { DBG("userspace probe offset calculation failed for " "function %s", symbol); @@ -292,7 +291,7 @@ end: static int extract_userspace_probe_offset_tracepoint_sdt( const struct lttng_userspace_probe_location *probe_location, - struct ltt_kernel_session *session, uint64_t **offsets, + uid_t uid, gid_t gid, uint64_t **offsets, uint32_t *offsets_count) { enum lttng_userspace_probe_location_lookup_method_type lookup_method_type; @@ -338,7 +337,7 @@ int extract_userspace_probe_offset_tracepoint_sdt( } ret = run_as_extract_sdt_probe_offsets(fd, provider_name, probe_name, - session->uid, session->gid, offsets, offsets_count); + uid, gid, offsets, offsets_count); if (ret < 0) { DBG("userspace probe offset calculation failed for sdt " "probe %s:%s", provider_name, probe_name); @@ -359,29 +358,16 @@ end: return ret; } -/* - * Extract the offsets of the instrumentation point for the different lookup - * methods. - */ static -int userspace_probe_add_callsites(struct lttng_event *ev, - struct ltt_kernel_session *session, int fd) +int userspace_probe_add_callsite( + const struct lttng_userspace_probe_location *location, + uid_t uid, gid_t gid, int fd) { const struct lttng_userspace_probe_location_lookup_method *lookup_method = NULL; enum lttng_userspace_probe_location_lookup_method_type type; - const struct lttng_userspace_probe_location *location = NULL; int ret; - assert(ev); - assert(ev->type == LTTNG_EVENT_USERSPACE_PROBE); - - location = lttng_event_get_userspace_probe_location(ev); - if (!location) { - ret = -1; - goto end; - } - lookup_method = - lttng_userspace_probe_location_get_lookup_method(location); + lookup_method = lttng_userspace_probe_location_get_lookup_method(location); if (!lookup_method) { ret = -1; goto end; @@ -394,7 +380,8 @@ int userspace_probe_add_callsites(struct lttng_event *ev, struct lttng_kernel_event_callsite callsite; uint64_t offset; - ret = extract_userspace_probe_offset_function_elf(location, session, &offset); + ret = extract_userspace_probe_offset_function_elf(location, + uid, gid, &offset); if (ret) { ret = LTTNG_ERR_PROBE_LOCATION_INVAL; goto end; @@ -403,8 +390,7 @@ int userspace_probe_add_callsites(struct lttng_event *ev, callsite.u.uprobe.offset = offset; ret = kernctl_add_callsite(fd, &callsite); if (ret) { - WARN("Adding callsite to userspace probe " - "event %s failed.", ev->name); + WARN("Failed to add callsite to ELF userspace probe."); ret = LTTNG_ERR_KERN_ENABLE_FAIL; goto end; } @@ -421,8 +407,8 @@ int userspace_probe_add_callsites(struct lttng_event *ev, * This call allocates the offsets buffer. This buffer must be freed * by the caller */ - ret = extract_userspace_probe_offset_tracepoint_sdt(location, session, - &offsets, &offsets_count); + ret = extract_userspace_probe_offset_tracepoint_sdt(location, + uid, gid, &offsets, &offsets_count); if (ret) { ret = LTTNG_ERR_PROBE_LOCATION_INVAL; goto end; @@ -431,8 +417,7 @@ int userspace_probe_add_callsites(struct lttng_event *ev, callsite.u.uprobe.offset = offsets[i]; ret = kernctl_add_callsite(fd, &callsite); if (ret) { - WARN("Adding callsite to userspace probe " - "event %s failed.", ev->name); + WARN("Failed to add callsite to SDT userspace probe"); ret = LTTNG_ERR_KERN_ENABLE_FAIL; free(offsets); goto end; @@ -449,6 +434,37 @@ end: return ret; } +/* + * Extract the offsets of the instrumentation point for the different lookup + * methods. + */ +static +int userspace_probe_event_add_callsites(struct lttng_event *ev, + struct ltt_kernel_session *session, int fd) +{ + int ret; + const struct lttng_userspace_probe_location *location = NULL; + + assert(ev); + assert(ev->type == LTTNG_EVENT_USERSPACE_PROBE); + + location = lttng_event_get_userspace_probe_location(ev); + if (!location) { + ret = -1; + goto end; + } + + ret = userspace_probe_add_callsite(location, session->uid, session->gid, + fd); + if (ret) { + WARN("Failed to add callsite to userspace probe event '%s'", + ev->name); + } + +end: + return ret; +} + /* * Create a kernel event, enable it to the kernel tracer and add it to the * channel event list of the kernel session. @@ -518,7 +534,8 @@ int kernel_create_event(struct lttng_event *ev, } if (ev->type == LTTNG_EVENT_USERSPACE_PROBE) { - ret = userspace_probe_add_callsites(ev, channel->session, event->fd); + ret = userspace_probe_event_add_callsites(ev, channel->session, + event->fd); if (ret) { goto add_callsite_error; } -- 2.34.1