Started implementing an utility to manage PCI passthrough

src/backing.h

@@ -57,7 +57,7 @@ result_t remove_backing(const char* backing);
 bool backing_filter(const char* file);
 
 /// @brief Lists the backings in the pool.
-/// @param _backings The string pointer array to store the resulting array in. The caller is responsible for freeing the strings and the array.
+/// @param _backings The string array pointer to store the resulting array in. The caller is responsible for freeing the strings and the array.
 /// @return The result of the operation.
 result_t list_backings(char*** _backings);
 

src/container.c

@@ -236,6 +236,7 @@ result_t list_containers(char*** _containers) {
 	// List the files in the container pool
 	result = list_files(_containers, pool_path, container_filter);
 
+	// Free the path
 	free(pool_path);
 	return result;
 }

src/container.h

@@ -59,7 +59,7 @@ result_t reset_container(const char* container);
 bool container_filter(const char* file);
 
 /// @brief Lists the containers in the pool.
-/// @param _containers The string pointer array to store the resulting array in. The caller is responsible for freeing the strings and the array.
+/// @param _containers The string array pointer to store the resulting array in. The caller is responsible for freeing the strings and the array.
 /// @return The result of the operation.
 result_t list_containers(char*** _containers);
 

src/pci.c

@@ -0,0 +1,119 @@
+#include "pci.h"
+
+#include <stdio.h>
+#include <string.h>
+#include <ctype.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <libgen.h>
+#include <sys/stat.h>
+
+result_t check_pci_address(const char* pci) {
+	// Check the length of the string (should be 12 characters, eg. 0000:00:00.0)
+	if (strlen(pci) != 12)
+		return failure("Invalid PCI address '%s'. Valid PCI addresses are in the format '0000:00:00.0'.", pci);
+
+	// Check the format of the string
+	for (int i = 0; i < 12; i++)
+		if (i == 4 || i == 7) {
+			if (pci[i] != ':')
+				return failure("Invalid PCI address '%s'. Missing colon at position %d. Valid PCI addresses are in the format '0000:00:00.0'.", pci, i);
+		} else if (i == 10) {
+			if (pci[i] != '.')
+				return failure("Invalid PCI address '%s'. Missing dot at position %d. Valid PCI addresses are in the format '0000:00:00.0'.", pci, i);
+		} else {
+			if (!isxdigit(pci[i]))
+				return failure("Invalid PCI address '%s'. Non-hexadecimal character '%c' at position %d. Valid PCI addresses are in the format '0000:00:00.0'.", pci, pci[i], i);
+		}
+
+	return success();
+}
+
+result_t check_pci_exists(const char* pci) {
+	// Check the PCI address format
+	result_t result = check_pci_address(pci);
+	if (result != success())
+		return result;
+
+	// Check if the PCI address exists by checking if the sysfs directory exists
+	char* path;
+	result = format(&path, "/sys/bus/pci/devices/%s", pci);
+	if (result != success())
+		return result;
+
+	// Check that the directory exists
+	struct stat st;
+	if (stat(path, &st) != 0 || !S_ISDIR(st.st_mode)) {
+		free(path);
+		return failure("PCI address '%s' does not exist.", pci);
+	}
+
+	// Free the path
+	free(path);
+
+	return success();
+}
+
+result_t get_iommu_group(int* _group, const char* pci) {
+	// Initialize the output parameter
+	*_group = -1;
+
+	// Check that the PCI address exists
+	result_t result = check_pci_exists(pci);
+	if (result != success())
+		return result;
+
+	// Get the IOMMU group if the PCI device has one
+	char* path;
+	result = format(&path, "/sys/bus/pci/devices/%s/iommu_group", pci);
+	if (result != success())
+		return result;
+
+	// Check that the file exists and is a symlink
+	struct stat st;
+	if (lstat(path, &st) != 0 || !S_ISLNK(st.st_mode)) {
+		free(path);
+		return failure("PCI address '%s' does not have an IOMMU group.", pci);
+	}
+
+	// Read the IOMMU group by getting the path of the symlink, and getting the basename of the path
+	char iommu_group_path[256]; // 256 should be enough for the path
+	ssize_t len = readlink(path, iommu_group_path, sizeof(iommu_group_path) - 1);
+
+	// Check for errors during the readlink call
+	if (len == -1) {
+		free(path);
+		return failure("Failed to read IOMMU group of PCI address '%s'.", pci);
+	}
+
+	// Null-terminate the path
+	iommu_group_path[len] = '\0';
+
+	// Get the basename of the path, and try to parse it as an integer
+	*_group = atoi(basename(iommu_group_path));
+
+	return success();
+}
+
+bool pci_filter(const char* file) {
+	// Check that the PCI device exists
+	return check_pci_exists(file) == success();
+}
+
+result_t get_iommu_group_devices(char*** _devices, int group) {
+	// Initialize the output parameters
+	*_devices = NULL;
+
+	// Get the path of the IOMMU group
+	char* path;
+	result_t result = format(&path, "/sys/kernel/iommu_groups/%d/devices", group);
+	if (result != success())
+		return result;
+
+	// List the devices in the IOMMU group
+	result = list_files(_devices, path, pci_filter);
+
+	// Free the path
+	free(path);
+	return result;
+}

src/pci.h

@@ -0,0 +1,30 @@
+#pragma once
+
+#include "utils.h"
+
+/// @brief Checks whether the given string is a valid PCI address. If the string is not a valid PCI address, the call will return a failure result with an error message.
+/// @param pci The string to check.
+/// @return The result of the operation.
+result_t check_pci_address(const char* pci);
+
+/// @brief Checks whether the given PCI address exists. If the PCI address does not exist, the call will return a failure result with an error message.
+/// @param pci The PCI address to check.
+/// @return The result of the operation.
+result_t check_pci_exists(const char* pci);
+
+/// @brief Gets the IOMMU group of the given PCI address.
+/// @param _group The integer pointer to store the resulting IOMMU group in.
+/// @param pci The PCI address to get the IOMMU group of.
+/// @return The result of the operation.
+result_t get_iommu_group(int* _group, const char* pci);
+
+/// @brief Checks that the given file is a PCI device. This function is used as a filter for listing PCI devices.
+/// @param file The file to check.
+/// @return Whether the file is a PCI device.
+bool pci_filter(const char* file);
+
+/// @brief Get the PCI devices in the given IOMMU group.
+/// @param _devices The string array pointer to store the resulting devices in. The caller is responsible for freeing the strings and the array.
+/// @param group The IOMMU group to get the devices of.
+/// @return The result of the operation.
+result_t get_iommu_group_devices(char*** _devices, int group);

src/sandbox.c

@@ -9,6 +9,8 @@
 #include <pwd.h>
 #include <unistd.h>
 
+#include "pci.h"
+
 #define ALIAS(...) \
 	(const char*[]) { __VA_ARGS__, NULL }
 

src/utils.h

@@ -120,8 +120,8 @@ result_t write_file(const char* path, const char* str);
 /// @return The result of the operation.
 result_t copy_file(const char* src, const char* dst);
 
-/// @brief Lists the files in the given directory, and stores the resulting array in the given string pointer array. A filter can be provided to only include files that match the filter.
-/// @param _files The string pointer array to store the resulting array in. The caller is responsible for freeing the strings and the array.
+/// @brief Lists the files in the given directory, and stores the resulting array in the given string array pointer. A filter can be provided to only include files that match the filter.
+/// @param _files The string array pointer to store the resulting array in. The caller is responsible for freeing the strings and the array.
 /// @param path The path to the directory to list the files in.
 /// @param filter The filter to use to only include files that match the filter. This parameter can be NULL if no filter is needed.
 /// @return The result of the operation.

src/xml.c

@@ -8,7 +8,7 @@ result_t generate_iso_xml(char** _xml, char* iso_path, int index) {
 		return failure("Too many ISO images");
 
 	// Generate the XML
-	return foramt(_xml, "<disk type='file' device='cdrom'>"
+	return format(_xml, "<disk type='file' device='cdrom'>"
 						"  <driver name='qemu' type='raw'/>"
 						"  <source file='%s'/>"
 						"  <target dev='sd%c' bus='sata'/>"