From 46820c8b8f1fbbc15b3afdbb18472b703da1fcd4 Mon Sep 17 00:00:00 2001
From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Date: Mon, 15 Sep 2014 15:07:02 -0400
Subject: [PATCH] Implement kernctl_syscall_mask

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: David Goulet <dgoulet@efficios.com>
---
 src/{lib/lttng-ctl/filter => common}/align.h  |  0
 src/{lib/lttng-ctl/filter => common}/bug.h    |  0
 src/common/kernel-ctl/kernel-ctl.c            | 51 +++++++++++++++++++
 src/common/kernel-ctl/kernel-ctl.h            | 14 +++++
 src/common/lttng-kernel.h                     |  2 +-
 .../filter/filter-visitor-generate-bytecode.c |  3 +-
 6 files changed, 68 insertions(+), 2 deletions(-)
 rename src/{lib/lttng-ctl/filter => common}/align.h (100%)
 rename src/{lib/lttng-ctl/filter => common}/bug.h (100%)

diff --git a/src/lib/lttng-ctl/filter/align.h b/src/common/align.h
similarity index 100%
rename from src/lib/lttng-ctl/filter/align.h
rename to src/common/align.h
diff --git a/src/lib/lttng-ctl/filter/bug.h b/src/common/bug.h
similarity index 100%
rename from src/lib/lttng-ctl/filter/bug.h
rename to src/common/bug.h
diff --git a/src/common/kernel-ctl/kernel-ctl.c b/src/common/kernel-ctl/kernel-ctl.c
index 078d85280..6cc962703 100644
--- a/src/common/kernel-ctl/kernel-ctl.c
+++ b/src/common/kernel-ctl/kernel-ctl.c
@@ -19,6 +19,7 @@
 #define __USE_LINUX_IOCTL_DEFS
 #include <sys/ioctl.h>
 #include <string.h>
+#include <common/align.h>
 
 #include "kernel-ctl.h"
 #include "kernel-ioctl.h"
@@ -163,6 +164,56 @@ int kernctl_disable_syscall(int fd, const char *syscall_name)
 	return ioctl(fd, LTTNG_KERNEL_EVENT, &event);
 }
 
+int kernctl_syscall_mask(int fd, char **syscall_mask, uint32_t *nr_bits)
+{
+	struct lttng_kernel_syscall_mask kmask_len, *kmask = NULL;
+	size_t array_alloc_len;
+	char *new_mask;
+	int ret = 0;
+
+	if (!syscall_mask) {
+		ret = -1;
+		goto end;
+	}
+
+	if (!nr_bits) {
+		ret = -1;
+		goto end;
+	}
+
+	kmask_len.len = 0;
+	ret = ioctl(fd, LTTNG_KERNEL_SYSCALL_MASK, &kmask_len);
+	if (ret) {
+		goto end;
+	}
+
+	array_alloc_len = ALIGN(kmask_len.len, 8) >> 3;
+	kmask = zmalloc(sizeof(*kmask) + array_alloc_len);
+	if (!kmask) {
+		ret = -1;
+		goto end;
+	}
+
+	kmask->len = kmask_len.len;
+	ret = ioctl(fd, LTTNG_KERNEL_SYSCALL_MASK, kmask);
+	if (ret) {
+		goto end;
+	}
+
+	new_mask = realloc(syscall_mask, array_alloc_len);
+	if (!new_mask) {
+		ret = -1;
+		goto end;
+	}
+	memcpy(new_mask, kmask->mask, array_alloc_len);
+	*syscall_mask = new_mask;
+	*nr_bits = kmask->len;
+
+end:
+	free(kmask);
+	return ret;
+}
+
 int kernctl_create_stream(int fd)
 {
 	return compat_ioctl_no_arg(fd, LTTNG_KERNEL_OLD_STREAM,
diff --git a/src/common/kernel-ctl/kernel-ctl.h b/src/common/kernel-ctl/kernel-ctl.h
index a20c68997..4ef1b8795 100644
--- a/src/common/kernel-ctl/kernel-ctl.h
+++ b/src/common/kernel-ctl/kernel-ctl.h
@@ -44,6 +44,20 @@ int kernctl_calibrate(int fd, struct lttng_kernel_calibrate *calibrate);
 int kernctl_enable_syscall(int fd, const char *syscall_name);
 int kernctl_disable_syscall(int fd, const char *syscall_name);
 
+/*
+ * kernctl_syscall_mask - Get syscall mask associated to a channel FD.
+ *
+ * The parameter @syscall_mask should initially be either NULL or point
+ * to memory allocated with malloc(3) or realloc(3). When the function
+ * returns, it will point to a memory area of the size required for the
+ * bitmask (using realloc(3) to resize the memory).
+ *
+ * It returns 0 if OK, -1 on error. In all cases (error and OK),
+ * @syscall_mask should be freed by the caller with free(3).
+ */
+int kernctl_syscall_mask(int fd, char **syscall_mask,
+		uint32_t *nr_bits);
+
 /* Buffer operations */
 
 /* For mmap mode, readable without "get" operation */
diff --git a/src/common/lttng-kernel.h b/src/common/lttng-kernel.h
index a4ca1825d..4df324005 100644
--- a/src/common/lttng-kernel.h
+++ b/src/common/lttng-kernel.h
@@ -133,7 +133,7 @@ struct lttng_kernel_calibrate {
 } LTTNG_PACKED;
 
 struct lttng_kernel_syscall_mask {
-	uint32_t len;
+	uint32_t len;	/* in bits */
 	char mask[];
 } LTTNG_PACKED;
 
diff --git a/src/lib/lttng-ctl/filter/filter-visitor-generate-bytecode.c b/src/lib/lttng-ctl/filter/filter-visitor-generate-bytecode.c
index 1cf7cb5c3..4dd52d8d0 100644
--- a/src/lib/lttng-ctl/filter/filter-visitor-generate-bytecode.c
+++ b/src/lib/lttng-ctl/filter/filter-visitor-generate-bytecode.c
@@ -22,7 +22,8 @@
 #include <stdlib.h>
 #include <string.h>
 #include <errno.h>
-#include "align.h"
+#include <common/align.h>
+
 #include "filter-bytecode.h"
 #include "filter-ir.h"
 #include "filter-ast.h"
-- 
2.34.1