[lttng-dev] [PATCH 15/19] lttng: add system call instrumentation probe
Mathieu Desnoyers
mathieu.desnoyers at efficios.com
Sat Nov 26 10:03:40 EST 2011
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers at efficios.com>
---
drivers/staging/lttng/lttng-syscalls.c | 437 ++++++++++++++++++++++++++++++++
1 files changed, 437 insertions(+), 0 deletions(-)
create mode 100644 drivers/staging/lttng/lttng-syscalls.c
diff --git a/drivers/staging/lttng/lttng-syscalls.c b/drivers/staging/lttng/lttng-syscalls.c
new file mode 100644
index 0000000..9de3c07
--- /dev/null
+++ b/drivers/staging/lttng/lttng-syscalls.c
@@ -0,0 +1,437 @@
+/*
+ * lttng-syscalls.c
+ *
+ * Copyright 2010-2011 (c) - Mathieu Desnoyers <mathieu.desnoyers at efficios.com>
+ *
+ * LTTng syscall probes.
+ *
+ * Dual LGPL v2.1/GPL v2 license.
+ */
+
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/compat.h>
+#include <asm/ptrace.h>
+#include <asm/syscall.h>
+
+#include "ltt-events.h"
+
+#ifndef CONFIG_COMPAT
+static inline int is_compat_task(void)
+{
+ return 0;
+}
+#endif
+
+static
+void syscall_entry_probe(void *__data, struct pt_regs *regs, long id);
+
+/*
+ * Take care of NOARGS not supported by mainline.
+ */
+#define DECLARE_EVENT_CLASS_NOARGS(name, tstruct, assign, print)
+#define DEFINE_EVENT_NOARGS(template, name)
+#define TRACE_EVENT_NOARGS(name, struct, assign, print)
+
+/*
+ * Create LTTng tracepoint probes.
+ */
+#define LTTNG_PACKAGE_BUILD
+#define CREATE_TRACE_POINTS
+#define TP_MODULE_OVERRIDE
+#define TRACE_INCLUDE_PATH ../instrumentation/syscalls/headers
+
+#define PARAMS(args...) args
+
+/* Hijack probe callback for system calls */
+#undef TP_PROBE_CB
+#define TP_PROBE_CB(_template) &syscall_entry_probe
+#define SC_TRACE_EVENT(_name, _proto, _args, _struct, _assign, _printk) \
+ TRACE_EVENT(_name, PARAMS(_proto), PARAMS(_args),\
+ PARAMS(_struct), PARAMS(_assign), PARAMS(_printk))
+#define SC_DECLARE_EVENT_CLASS_NOARGS(_name, _struct, _assign, _printk) \
+ DECLARE_EVENT_CLASS_NOARGS(_name, PARAMS(_struct), PARAMS(_assign),\
+ PARAMS(_printk))
+#define SC_DEFINE_EVENT_NOARGS(_template, _name) \
+ DEFINE_EVENT_NOARGS(_template, _name)
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM syscalls_integers
+#include "instrumentation/syscalls/headers/syscalls_integers.h"
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM syscalls_pointers
+#include "instrumentation/syscalls/headers/syscalls_pointers.h"
+#undef TRACE_SYSTEM
+#undef SC_TRACE_EVENT
+#undef SC_DECLARE_EVENT_CLASS_NOARGS
+#undef SC_DEFINE_EVENT_NOARGS
+
+#define TRACE_SYSTEM syscalls_unknown
+#include "instrumentation/syscalls/headers/syscalls_unknown.h"
+#undef TRACE_SYSTEM
+
+/* For compat syscalls */
+#undef _TRACE_SYSCALLS_integers_H
+#undef _TRACE_SYSCALLS_pointers_H
+
+/* Hijack probe callback for system calls */
+#undef TP_PROBE_CB
+#define TP_PROBE_CB(_template) &syscall_entry_probe
+#define SC_TRACE_EVENT(_name, _proto, _args, _struct, _assign, _printk) \
+ TRACE_EVENT(compat_##_name, PARAMS(_proto), PARAMS(_args), \
+ PARAMS(_struct), PARAMS(_assign), \
+ PARAMS(_printk))
+#define SC_DECLARE_EVENT_CLASS_NOARGS(_name, _struct, _assign, _printk) \
+ DECLARE_EVENT_CLASS_NOARGS(compat_##_name, PARAMS(_struct), \
+ PARAMS(_assign), PARAMS(_printk))
+#define SC_DEFINE_EVENT_NOARGS(_template, _name) \
+ DEFINE_EVENT_NOARGS(compat_##_template, compat_##_name)
+#define TRACE_SYSTEM compat_syscalls_integers
+#include "instrumentation/syscalls/headers/compat_syscalls_integers.h"
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM compat_syscalls_pointers
+#include "instrumentation/syscalls/headers/compat_syscalls_pointers.h"
+#undef TRACE_SYSTEM
+#undef SC_TRACE_EVENT
+#undef SC_DECLARE_EVENT_CLASS_NOARGS
+#undef SC_DEFINE_EVENT_NOARGS
+#undef TP_PROBE_CB
+
+#undef TP_MODULE_OVERRIDE
+#undef LTTNG_PACKAGE_BUILD
+#undef CREATE_TRACE_POINTS
+
+struct trace_syscall_entry {
+ void *func;
+ const struct lttng_event_desc *desc;
+ const struct lttng_event_field *fields;
+ unsigned int nrargs;
+};
+
+#define CREATE_SYSCALL_TABLE
+
+#undef TRACE_SYSCALL_TABLE
+#define TRACE_SYSCALL_TABLE(_template, _name, _nr, _nrargs) \
+ [ _nr ] = { \
+ .func = __event_probe__##_template, \
+ .nrargs = (_nrargs), \
+ .fields = __event_fields___##_template, \
+ .desc = &__event_desc___##_name, \
+ },
+
+static const struct trace_syscall_entry sc_table[] = {
+#include "instrumentation/syscalls/headers/syscalls_integers.h"
+#include "instrumentation/syscalls/headers/syscalls_pointers.h"
+};
+
+#undef TRACE_SYSCALL_TABLE
+#define TRACE_SYSCALL_TABLE(_template, _name, _nr, _nrargs) \
+ [ _nr ] = { \
+ .func = __event_probe__##compat_##_template, \
+ .nrargs = (_nrargs), \
+ .fields = __event_fields___##compat_##_template,\
+ .desc = &__event_desc___##compat_##_name, \
+ },
+
+/* Create compatibility syscall table */
+const struct trace_syscall_entry compat_sc_table[] = {
+#include "instrumentation/syscalls/headers/compat_syscalls_integers.h"
+#include "instrumentation/syscalls/headers/compat_syscalls_pointers.h"
+};
+
+#undef CREATE_SYSCALL_TABLE
+
+static void syscall_entry_unknown(struct ltt_event *event,
+ struct pt_regs *regs, unsigned int id)
+{
+ unsigned long args[UNKNOWN_SYSCALL_NRARGS];
+
+ syscall_get_arguments(current, regs, 0, UNKNOWN_SYSCALL_NRARGS, args);
+ if (unlikely(is_compat_task()))
+ __event_probe__compat_sys_unknown(event, id, args);
+ else
+ __event_probe__sys_unknown(event, id, args);
+}
+
+void syscall_entry_probe(void *__data, struct pt_regs *regs, long id)
+{
+ struct ltt_channel *chan = __data;
+ struct ltt_event *event, *unknown_event;
+ const struct trace_syscall_entry *table, *entry;
+ size_t table_len;
+
+ if (unlikely(is_compat_task())) {
+ table = compat_sc_table;
+ table_len = ARRAY_SIZE(compat_sc_table);
+ unknown_event = chan->sc_compat_unknown;
+ } else {
+ table = sc_table;
+ table_len = ARRAY_SIZE(sc_table);
+ unknown_event = chan->sc_unknown;
+ }
+ if (unlikely(id >= table_len)) {
+ syscall_entry_unknown(unknown_event, regs, id);
+ return;
+ }
+ if (unlikely(is_compat_task()))
+ event = chan->compat_sc_table[id];
+ else
+ event = chan->sc_table[id];
+ if (unlikely(!event)) {
+ syscall_entry_unknown(unknown_event, regs, id);
+ return;
+ }
+ entry = &table[id];
+ WARN_ON_ONCE(!entry);
+
+ switch (entry->nrargs) {
+ case 0:
+ {
+ void (*fptr)(void *__data) = entry->func;
+
+ fptr(event);
+ break;
+ }
+ case 1:
+ {
+ void (*fptr)(void *__data, unsigned long arg0) = entry->func;
+ unsigned long args[1];
+
+ syscall_get_arguments(current, regs, 0, entry->nrargs, args);
+ fptr(event, args[0]);
+ break;
+ }
+ case 2:
+ {
+ void (*fptr)(void *__data,
+ unsigned long arg0,
+ unsigned long arg1) = entry->func;
+ unsigned long args[2];
+
+ syscall_get_arguments(current, regs, 0, entry->nrargs, args);
+ fptr(event, args[0], args[1]);
+ break;
+ }
+ case 3:
+ {
+ void (*fptr)(void *__data,
+ unsigned long arg0,
+ unsigned long arg1,
+ unsigned long arg2) = entry->func;
+ unsigned long args[3];
+
+ syscall_get_arguments(current, regs, 0, entry->nrargs, args);
+ fptr(event, args[0], args[1], args[2]);
+ break;
+ }
+ case 4:
+ {
+ void (*fptr)(void *__data,
+ unsigned long arg0,
+ unsigned long arg1,
+ unsigned long arg2,
+ unsigned long arg3) = entry->func;
+ unsigned long args[4];
+
+ syscall_get_arguments(current, regs, 0, entry->nrargs, args);
+ fptr(event, args[0], args[1], args[2], args[3]);
+ break;
+ }
+ case 5:
+ {
+ void (*fptr)(void *__data,
+ unsigned long arg0,
+ unsigned long arg1,
+ unsigned long arg2,
+ unsigned long arg3,
+ unsigned long arg4) = entry->func;
+ unsigned long args[5];
+
+ syscall_get_arguments(current, regs, 0, entry->nrargs, args);
+ fptr(event, args[0], args[1], args[2], args[3], args[4]);
+ break;
+ }
+ case 6:
+ {
+ void (*fptr)(void *__data,
+ unsigned long arg0,
+ unsigned long arg1,
+ unsigned long arg2,
+ unsigned long arg3,
+ unsigned long arg4,
+ unsigned long arg5) = entry->func;
+ unsigned long args[6];
+
+ syscall_get_arguments(current, regs, 0, entry->nrargs, args);
+ fptr(event, args[0], args[1], args[2],
+ args[3], args[4], args[5]);
+ break;
+ }
+ default:
+ break;
+ }
+}
+
+/* noinline to diminish caller stack size */
+static
+int fill_table(const struct trace_syscall_entry *table, size_t table_len,
+ struct ltt_event **chan_table, struct ltt_channel *chan, void *filter)
+{
+ const struct lttng_event_desc *desc;
+ unsigned int i;
+
+ /* Allocate events for each syscall, insert into table */
+ for (i = 0; i < table_len; i++) {
+ struct lttng_kernel_event ev;
+ desc = table[i].desc;
+
+ if (!desc) {
+ /* Unknown syscall */
+ continue;
+ }
+ /*
+ * Skip those already populated by previous failed
+ * register for this channel.
+ */
+ if (chan_table[i])
+ continue;
+ memset(&ev, 0, sizeof(ev));
+ strncpy(ev.name, desc->name, LTTNG_SYM_NAME_LEN);
+ ev.name[LTTNG_SYM_NAME_LEN - 1] = '\0';
+ ev.instrumentation = LTTNG_KERNEL_NOOP;
+ chan_table[i] = ltt_event_create(chan, &ev, filter,
+ desc);
+ if (!chan_table[i]) {
+ /*
+ * If something goes wrong in event registration
+ * after the first one, we have no choice but to
+ * leave the previous events in there, until
+ * deleted by session teardown.
+ */
+ return -EINVAL;
+ }
+ }
+ return 0;
+}
+
+int lttng_syscalls_register(struct ltt_channel *chan, void *filter)
+{
+ struct lttng_kernel_event ev;
+ int ret;
+
+ wrapper_vmalloc_sync_all();
+
+ if (!chan->sc_table) {
+ /* create syscall table mapping syscall to events */
+ chan->sc_table = kzalloc(sizeof(struct ltt_event *)
+ * ARRAY_SIZE(sc_table), GFP_KERNEL);
+ if (!chan->sc_table)
+ return -ENOMEM;
+ }
+
+#ifdef CONFIG_COMPAT
+ if (!chan->compat_sc_table) {
+ /* create syscall table mapping compat syscall to events */
+ chan->compat_sc_table = kzalloc(sizeof(struct ltt_event *)
+ * ARRAY_SIZE(compat_sc_table), GFP_KERNEL);
+ if (!chan->compat_sc_table)
+ return -ENOMEM;
+ }
+#endif
+ if (!chan->sc_unknown) {
+ const struct lttng_event_desc *desc =
+ &__event_desc___sys_unknown;
+
+ memset(&ev, 0, sizeof(ev));
+ strncpy(ev.name, desc->name, LTTNG_SYM_NAME_LEN);
+ ev.name[LTTNG_SYM_NAME_LEN - 1] = '\0';
+ ev.instrumentation = LTTNG_KERNEL_NOOP;
+ chan->sc_unknown = ltt_event_create(chan, &ev, filter,
+ desc);
+ if (!chan->sc_unknown) {
+ return -EINVAL;
+ }
+ }
+
+ if (!chan->sc_compat_unknown) {
+ const struct lttng_event_desc *desc =
+ &__event_desc___compat_sys_unknown;
+
+ memset(&ev, 0, sizeof(ev));
+ strncpy(ev.name, desc->name, LTTNG_SYM_NAME_LEN);
+ ev.name[LTTNG_SYM_NAME_LEN - 1] = '\0';
+ ev.instrumentation = LTTNG_KERNEL_NOOP;
+ chan->sc_compat_unknown = ltt_event_create(chan, &ev, filter,
+ desc);
+ if (!chan->sc_compat_unknown) {
+ return -EINVAL;
+ }
+ }
+
+ if (!chan->sc_exit) {
+ const struct lttng_event_desc *desc =
+ &__event_desc___exit_syscall;
+
+ memset(&ev, 0, sizeof(ev));
+ strncpy(ev.name, desc->name, LTTNG_SYM_NAME_LEN);
+ ev.name[LTTNG_SYM_NAME_LEN - 1] = '\0';
+ ev.instrumentation = LTTNG_KERNEL_NOOP;
+ chan->sc_exit = ltt_event_create(chan, &ev, filter,
+ desc);
+ if (!chan->sc_exit) {
+ return -EINVAL;
+ }
+ }
+
+ ret = fill_table(sc_table, ARRAY_SIZE(sc_table),
+ chan->sc_table, chan, filter);
+ if (ret)
+ return ret;
+#ifdef CONFIG_COMPAT
+ ret = fill_table(compat_sc_table, ARRAY_SIZE(compat_sc_table),
+ chan->compat_sc_table, chan, filter);
+ if (ret)
+ return ret;
+#endif
+ ret = tracepoint_probe_register("sys_enter",
+ (void *) syscall_entry_probe, chan);
+ if (ret)
+ return ret;
+ /*
+ * We change the name of sys_exit tracepoint due to namespace
+ * conflict with sys_exit syscall entry.
+ */
+ ret = tracepoint_probe_register("sys_exit",
+ (void *) __event_probe__exit_syscall,
+ chan->sc_exit);
+ if (ret) {
+ WARN_ON_ONCE(tracepoint_probe_unregister("sys_enter",
+ (void *) syscall_entry_probe, chan));
+ }
+ return ret;
+}
+
+/*
+ * Only called at session destruction.
+ */
+int lttng_syscalls_unregister(struct ltt_channel *chan)
+{
+ int ret;
+
+ if (!chan->sc_table)
+ return 0;
+ ret = tracepoint_probe_unregister("sys_exit",
+ (void *) __event_probe__exit_syscall,
+ chan->sc_exit);
+ if (ret)
+ return ret;
+ ret = tracepoint_probe_unregister("sys_enter",
+ (void *) syscall_entry_probe, chan);
+ if (ret)
+ return ret;
+ /* ltt_event destroy will be performed by ltt_session_destroy() */
+ kfree(chan->sc_table);
+#ifdef CONFIG_COMPAT
+ kfree(chan->compat_sc_table);
+#endif
+ return 0;
+}
--
1.7.2.5
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