Introduce devset_init

Signed-off-by: Grzegorz Nosek <[email protected]>

userspace/libscap/CMakeLists.txt

@@ -90,7 +90,8 @@ list(APPEND targetfiles
 	syscall_info_table.c
 	../../driver/dynamic_params_table.c
 	../../driver/event_table.c
-	../../driver/flags_table.c)
+	../../driver/flags_table.c
+	ringbuffer/devset.c)
 
 if(NOT APPLE)
 	list(APPEND targetfiles

userspace/libscap/ringbuffer/devset.c

@@ -0,0 +1,40 @@
+#include "devset.h"
+
+#include <stdlib.h>
+#include <stdint.h>
+#include <stdio.h>
+
+#ifndef _WIN32
+#include <sys/mman.h>
+#endif
+
+#include "../../common/strlcpy.h"
+#include "../scap.h"
+#include "../scap-int.h"
+
+int32_t devset_init(struct scap_device_set *devset, size_t num_devs, char *lasterr)
+{
+	devset->m_ndevs = num_devs;
+
+	devset->m_devs = (scap_device*) calloc(sizeof(scap_device), devset->m_ndevs);
+	if(!devset->m_devs)
+	{
+		strlcpy(lasterr, "error allocating the device handles", SCAP_LASTERR_SIZE);
+		return SCAP_FAILURE;
+	}
+
+	for(size_t j = 0; j < num_devs; ++j)
+	{
+		devset->m_devs[j].m_buffer = MAP_FAILED;
+		devset->m_devs[j].m_bufinfo = MAP_FAILED;
+		devset->m_devs[j].m_bufstatus = MAP_FAILED;
+		devset->m_devs[j].m_fd = -1;
+		devset->m_devs[j].m_bufinfo_fd = -1;
+		devset->m_devs[j].m_lastreadsize = 0;
+		devset->m_devs[j].m_sn_len = 0;
+	}
+	devset->m_buffer_empty_wait_time_us = BUFFER_EMPTY_WAIT_TIME_US_START;
+	devset->m_lasterr = lasterr;
+
+	return SCAP_SUCCESS;
+}

userspace/libscap/ringbuffer/devset.h

@@ -0,0 +1,57 @@
+/*
+Copyright (C) 2022 The Falco Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+
+*/
+
+#pragma once
+
+#include <stdint.h>
+#include <stddef.h>
+
+struct ppm_ring_buffer_info;
+struct udig_ring_buffer_status;
+
+//
+// The device descriptor
+//
+typedef struct scap_device
+{
+	int m_fd;
+	int m_bufinfo_fd; // used by udig
+	char* m_buffer;
+	uint32_t m_buffer_size; // used by udig
+	uint32_t m_lastreadsize;
+	char* m_sn_next_event; // Pointer to the next event available for scap_next
+	uint32_t m_sn_len; // Number of bytes available in the buffer pointed by m_sn_next_event
+	union
+	{
+		// Anonymous struct with ppm stuff
+		struct
+		{
+			struct ppm_ring_buffer_info* m_bufinfo;
+			struct udig_ring_buffer_status* m_bufstatus; // used by udig
+		};
+	};
+} scap_device;
+
+struct scap_device_set
+{
+	scap_device* m_devs;
+	uint32_t m_ndevs;
+	uint64_t m_buffer_empty_wait_time_us;
+	char* m_lasterr;
+};
+
+int32_t devset_init(struct scap_device_set *devset, size_t num_devs, char *lasterr);

userspace/libscap/scap-int.h

@@ -25,6 +25,7 @@ limitations under the License.
 
 #include "engine_handle.h"
 #include "scap_vtable.h"
+#include "ringbuffer/devset.h"
 
 #include "settings.h"
 #include "plugin_info.h"
@@ -84,36 +85,6 @@ inline const char *gzerror(FILE *F, int *E) {*E = ferror(F); return "error readi
 
 #define BPF_MAPS_MAX 32
 
-//
-// The device descriptor
-//
-typedef struct scap_device
-{
-	int m_fd;
-	int m_bufinfo_fd; // used by udig
-	char* m_buffer;
-	uint32_t m_buffer_size; // used by udig
-	uint32_t m_lastreadsize;
-	char* m_sn_next_event; // Pointer to the next event available for scap_next
-	uint32_t m_sn_len; // Number of bytes available in the buffer pointed by m_sn_next_event
-	union
-	{
-		// Anonymous struct with ppm stuff
-		struct
-		{
-			struct ppm_ring_buffer_info* m_bufinfo;
-			struct udig_ring_buffer_status* m_bufstatus; // used by udig
-		};
-	};
-}scap_device;
-
-struct scap_device_set
-{
-	scap_device* m_devs;
-	uint32_t m_ndevs;
-	uint64_t m_buffer_empty_wait_time_us;
-};
-
 typedef struct scap_tid
 {
 	uint64_t tid;

userspace/libscap/scap.c

@@ -221,27 +221,13 @@ scap_t* scap_open_live_int(char *error, int32_t *rc,
 		return NULL;
 	}
 
-	handle->m_dev_set.m_devs = (scap_device*) calloc(sizeof(scap_device), ndevs);
-	if(!handle->m_dev_set.m_devs)
+	*rc = devset_init(&handle->m_dev_set, ndevs, error);
+	if(*rc != SCAP_SUCCESS)
 	{
 		scap_close(handle);
-		snprintf(error, SCAP_LASTERR_SIZE, "error allocating the device handles");
-		*rc = SCAP_FAILURE;
 		return NULL;
 	}
 
-	for(j = 0; j < ndevs; j++)
-	{
-		handle->m_dev_set.m_devs[j].m_buffer = (char*)MAP_FAILED;
-		if(!handle->m_bpf)
-		{
-			handle->m_dev_set.m_devs[j].m_bufinfo = (struct ppm_ring_buffer_info*)MAP_FAILED;
-			handle->m_dev_set.m_devs[j].m_bufstatus = (struct udig_ring_buffer_status*)MAP_FAILED;
-		}
-	}
-
-	handle->m_dev_set.m_ndevs = ndevs;
-
 	//
 	// Extract machine information
 	//
@@ -302,7 +288,6 @@ scap_t* scap_open_live_int(char *error, int32_t *rc,
 	handle->m_num_suppressed_comms = 0;
 	handle->m_suppressed_tids = NULL;
 	handle->m_num_suppressed_evts = 0;
-	handle->m_dev_set.m_buffer_empty_wait_time_us = BUFFER_EMPTY_WAIT_TIME_US_START;
 
 	if ((*rc = copy_comms(handle, suppressed_comms)) != SCAP_SUCCESS)
 	{
@@ -623,23 +608,13 @@ scap_t* scap_open_udig_int(char *error, int32_t *rc,
 	handle->m_udig_capturing = false;
 	handle->m_ncpus = 1;
 
-	handle->m_dev_set.m_ndevs = 1;
-
-	handle->m_dev_set.m_devs = (scap_device*) calloc(sizeof(scap_device), handle->m_dev_set.m_ndevs);
-	if(!handle->m_dev_set.m_devs)
+	*rc = devset_init(&handle->m_dev_set, 1, error);
+	if(*rc != SCAP_SUCCESS)
 	{
 		scap_close(handle);
-		snprintf(error, SCAP_LASTERR_SIZE, "error allocating the device handles");
-		*rc = SCAP_FAILURE;
 		return NULL;
 	}
 
-	handle->m_dev_set.m_devs[0].m_buffer = MAP_FAILED;
-	handle->m_dev_set.m_devs[0].m_bufinfo = MAP_FAILED;
-	handle->m_dev_set.m_devs[0].m_bufstatus = MAP_FAILED;
-	handle->m_dev_set.m_devs[0].m_fd = -1;
-	handle->m_dev_set.m_devs[0].m_bufinfo_fd = -1;
-
 	//
 	// Extract machine information
 	//
@@ -698,7 +673,6 @@ scap_t* scap_open_udig_int(char *error, int32_t *rc,
 	handle->m_num_suppressed_comms = 0;
 	handle->m_suppressed_tids = NULL;
 	handle->m_num_suppressed_evts = 0;
-	handle->m_dev_set.m_buffer_empty_wait_time_us = BUFFER_EMPTY_WAIT_TIME_US_START;
 
 #ifdef _WIN32
 	handle->m_whh = scap_windows_hal_open(error);