Merge pull request managarm#1705 from no92/if_nameindex

Implement if_nameindex

Author: Dennisbonke

options/internal/include/mlibc/all-sysdeps.hpp

@@ -7,6 +7,7 @@
 #include <bits/ensure.h>
 #include <errno.h>
 #include <mlibc/sysdeps.hpp>
+#include <mlibc/sysdep-traits.hpp>
 #include <utility>
 
 namespace mlibc {
@@ -85,6 +86,8 @@ static_assert(IsImplemented<VmUnmap>);
 static_assert(IsImplemented<TcbSet>);
 // ANCHOR_END: mandatory-sysdeps
 
+static_assert(AllSysdepTraits<SysdepTraits>);
+
 } // namespace mlibc
 
 #endif /* MLIBC_ALL_SYSDEPS */

options/internal/include/mlibc/sysdep-signatures.hpp

@@ -235,6 +235,8 @@ SYSDEP_FUNC(SetRegid, gid_t rgid, gid_t egid);
 SYSDEP_FUNC(GetLoginR, char *name, size_t name_len);
 SYSDEP_FUNC(IfIndextoname, unsigned int index, char *name);
 SYSDEP_FUNC(IfNametoindex, const char *name, unsigned int *ret);
+SYSDEP_FUNC(IfNameindex, struct if_nameindex **out);
+SYSDEP_FUNC_RET(void, IfFreeNameindex, struct if_nameindex *ifn);
 SYSDEP_FUNC(Ptsname, int fd, char *buffer, size_t length);
 SYSDEP_FUNC(Unlockpt, int fd);
 SYSDEP_FUNC(ThreadSetname, void *tcb, const char *name);
@@ -309,6 +311,7 @@ SYSDEP_FUNC(Statfs, const char *path, struct statfs *buf);
 SYSDEP_FUNC(Fstatfs, int fd, struct statfs *buf);
 SYSDEP_FUNC(Statx, int dirfd, const char *pathname, int flags, unsigned int mask, struct statx *statxbuf);
 SYSDEP_FUNC(Getifaddrs, struct ifaddrs **);
+SYSDEP_FUNC_RET(void, Freeifaddrs, struct ifaddrs *ifa);
 SYSDEP_FUNC(Sendfile, int outfd, int infd, off_t *offset, size_t count, ssize_t *out);
 SYSDEP_FUNC(Syncfs, int fd);
 SYSDEP_FUNC(Unshare, int flags);

options/internal/include/mlibc/sysdep-tags.hpp

@@ -195,6 +195,7 @@ struct RiscvFlushIcache {};
 #include <fcntl.h>
 #include <mlibc/fsfd_target.hpp>
 #include <mqueue.h>
+#include <net/if.h>
 #include <poll.h>
 #include <sched.h>
 #include <stdarg.h>
@@ -495,6 +496,10 @@ struct GetLoginR {};
 struct IfIndextoname {};
 // int sys_if_nametoindex(const char *name, unsigned int *ret);
 struct IfNametoindex {};
+// int sys_if_nameindex(struct if_nameindex **out);
+struct IfNameindex {};
+// void sys_if_freenameindex(struct if_nameindex *ifn);
+struct IfFreeNameindex {};
 // int sys_ptsname(int fd, char *buffer, size_t length);
 struct Ptsname {};
 // int sys_unlockpt(int fd);
@@ -654,6 +659,8 @@ struct Fstatfs {};
 struct Statx {};
 // int sys_getifaddrs(struct ifaddrs **);
 struct Getifaddrs {};
+// void sys_freeifaddrs(struct ifaddrs *ifa);
+struct Freeifaddrs {};
 // int sys_sendfile(int outfd, int infd, off_t *offset, size_t count, ssize_t *out);
 struct Sendfile {};
 // int sys_syncfs(int fd);

options/internal/include/mlibc/sysdep-traits.hpp

@@ -0,0 +1,8 @@
+#pragma once
+
+#include <type_traits>
+
+template <typename T>
+concept AllSysdepTraits = requires {
+	typename std::bool_constant<T::usesRtNetlink>;
+};

options/linux/generic/ifaddrs.cpp

@@ -13,9 +13,6 @@ int getifaddrs(struct ifaddrs **ifap) {
 }
 
 void freeifaddrs(struct ifaddrs *ifa) {
-	while (ifa != nullptr) {
-		ifaddrs *current = ifa;
-		ifa = ifa->ifa_next;
-		getAllocator().free(current);
-	}
+	if constexpr (mlibc::IsImplemented<Freeifaddrs>)
+		mlibc::sysdep_or_panic<Freeifaddrs>(ifa);
 }

options/posix/generic/net-if.cpp

@@ -1,13 +1,34 @@
 #include <errno.h>
 #include <net/if.h>
-#include <stdlib.h>
 
 #include <bits/ensure.h>
+#include <frg/vector.hpp>
 #include <mlibc/all-sysdeps.hpp>
+#include <mlibc/allocator.hpp>
 #include <mlibc/debug.hpp>
 
-void if_freenameindex(struct if_nameindex *) {
-	mlibc::infoLogger() << "mlibc: if_freenameindex is a no-op" << frg::endlog;
+#if __MLIBC_LINUX_OPTION
+#include <generic-helpers/netlink.hpp>
+#endif // __MLIBC_LINUX_OPTION
+
+void if_freenameindex(struct if_nameindex *p) {
+#if __MLIBC_LINUX_OPTION
+	if constexpr (mlibc::SysdepTraits::usesRtNetlink) {
+		if (!p)
+			return;
+
+		for (auto c = p; c->if_index || c->if_name; c++) {
+			if (c->if_name)
+				getAllocator().free(c->if_name);
+		}
+
+		getAllocator().free(p);
+		return;
+	}
+#endif
+
+	if constexpr (mlibc::IsImplemented<IfFreeNameindex>)
+		mlibc::sysdep_or_panic<IfFreeNameindex>(p);
 }
 
 char *if_indextoname(unsigned int index, char *name) {
@@ -20,9 +41,29 @@ char *if_indextoname(unsigned int index, char *name) {
 }
 
 struct if_nameindex *if_nameindex(void) {
-	mlibc::infoLogger() << "mlibc: if_nameindex() is a no-op" << frg::endlog;
-	errno = ENOSYS;
-	return nullptr;
+#if __MLIBC_LINUX_OPTION
+	if constexpr (mlibc::SysdepTraits::usesRtNetlink) {
+		NetlinkHelper nl;
+		frg::vector<struct if_nameindex, MemoryAllocator> list{getAllocator()};
+
+		bool link_ret = nl.send_request(RTM_GETLINK) && nl.recv(&if_nameindex_callback, &list);
+		__ensure(link_ret);
+
+		list.emplace_back(0, nullptr);
+		auto ret = list.data();
+		list.detach();
+
+		return ret;
+	}
+#endif
+
+	struct if_nameindex *out = nullptr;
+	if(int e = mlibc::sysdep_or_enosys<IfNameindex>(&out); e) {
+		errno = e;
+		return nullptr;
+	}
+
+	return out;
 }
 
 unsigned int if_nametoindex(const char *name) {

sysdeps/astral/include/mlibc/sysdeps.hpp

@@ -141,4 +141,8 @@ struct AstralSysdepTags :
 template<typename Tag>
 using Sysdeps = SysdepOf<AstralSysdepTags, Tag>;
 
+struct SysdepTraits {
+	static constexpr bool usesRtNetlink = false;
+};
+
 } // namespace mlibc

sysdeps/demo/include/mlibc/sysdeps.hpp

@@ -27,4 +27,8 @@ struct DemoSysdepTags :
 template<typename Tag>
 using Sysdeps = SysdepOf<DemoSysdepTags, Tag>;
 
+struct SysdepTraits {
+	static constexpr bool usesRtNetlink = false;
+};
+
 } // namespace mlibc

sysdeps/generic-helpers/include/generic-helpers/netlink.hpp

@@ -2,6 +2,7 @@
 
 #include <frg/allocation.hpp>
 #include <frg/span.hpp>
+#include <frg/vector.hpp>
 #include <ifaddrs.h>
 #include <linux/rtnetlink.h>
 #include <mlibc/all-sysdeps.hpp>
@@ -286,4 +287,28 @@ void getifaddrs_callback(void *context, const nlmsghdr *hdr) {
 	}
 }
 
+/**
+ * Callback function to be used with NetlinkHelper for implementing `sys_if_nameindex` by using rtnetlink.
+ */
+void if_nameindex_callback(void *context, const nlmsghdr *hdr) {
+	auto list = reinterpret_cast<frg::vector<struct if_nameindex, MemoryAllocator> *>(context);
+
+	if (hdr->nlmsg_type == RTM_NEWLINK) {
+		ifinfomsg *ifi = reinterpret_cast<ifinfomsg *>(NLMSG_DATA(hdr));
+
+		rtattr *rta = IFLA_RTA(ifi);
+		size_t rta_len = IFLA_PAYLOAD(hdr);
+
+		while (RTA_OK(rta, rta_len)) {
+			if (rta->rta_type == IFLA_IFNAME) {
+				auto name = strndup(reinterpret_cast<char *>(RTA_DATA(rta)), RTA_PAYLOAD(rta));
+				list->emplace_back(ifi->ifi_index, name);
+				return;
+			}
+
+			rta = RTA_NEXT(rta, rta_len);
+		}
+	}
+}
+
 } // namespace

sysdeps/ironclad/include/mlibc/sysdeps.hpp

@@ -158,4 +158,8 @@ struct IroncladSysdepTags :
 template<typename Tag>
 using Sysdeps = SysdepOf<IroncladSysdepTags, Tag>;
 
+struct SysdepTraits {
+	static constexpr bool usesRtNetlink = false;
+};
+
 } // namespace mlibc