[reland][libc] add epoll_wait functions (llvm#79635)

The epoll_wait functions are syscall wrappers that were requested by upstream users. This patch adds them, as well as their header and types. The tests are currently incomplete since they require epoll_create to properly test epoll_wait. That will be added in a followup patch since this one is already very large.
xgupta · Jan 30, 2024 · 9f3854a · 9f3854a
1 parent 69cb99f
commit 9f3854a
Show file tree

Hide file tree

Showing 34 changed files with 631 additions and 5 deletions.
diff --git a/libc/config/linux/aarch64/entrypoints.txt b/libc/config/linux/aarch64/entrypoints.txt
@@ -179,6 +179,12 @@ set(TARGET_LIBC_ENTRYPOINTS
     # sys/auxv.h entrypoints
     libc.src.sys.auxv.getauxval
 
+    # sys/epoll.h entrypoints
+    # Disabled due to epoll_wait syscalls not being available on this platform.
+    # libc.src.sys.epoll.epoll_wait
+    # libc.src.sys.epoll.epoll_pwait
+    # libc.src.sys.epoll.epoll_pwait2
+
     # termios.h entrypoints
     libc.src.termios.cfgetispeed
     libc.src.termios.cfgetospeed

diff --git a/libc/config/linux/aarch64/headers.txt b/libc/config/linux/aarch64/headers.txt
@@ -25,4 +25,6 @@ set(TARGET_PUBLIC_HEADERS
     libc.include.unistd
 
     libc.include.sys_ioctl
+    # Disabled due to epoll_wait syscalls not being available on this platform.
+    # libc.include.sys_epoll
 )
diff --git a/libc/config/linux/api.td b/libc/config/linux/api.td
@@ -1,11 +1,11 @@
 include "config/public_api.td"
 
-include "spec/bsd_ext.td"
-include "spec/gnu_ext.td"
+include "spec/stdc.td"
+include "spec/posix.td"
 include "spec/linux.td"
+include "spec/gnu_ext.td"
+include "spec/bsd_ext.td"
 include "spec/llvm_libc_ext.td"
-include "spec/posix.td"
-include "spec/stdc.td"
 
 def AssertMacro : MacroDef<"assert"> {
   let Defn = [{
@@ -242,6 +242,10 @@ def SysUtsNameAPI : PublicAPI<"sys/utsname.h"> {
   let Types = ["struct utsname"];
 }
 
+def SysEpollAPI : PublicAPI<"sys/epoll.h"> {
+  let Types = ["struct epoll_event", "struct epoll_data", "sigset_t", "struct timespec"];
+}
+
 def SpawnAPI : PublicAPI<"spawn.h"> {
   let Types = ["mode_t", "pid_t", "posix_spawnattr_t", "posix_spawn_file_actions_t"];
 }

diff --git a/libc/config/linux/arm/entrypoints.txt b/libc/config/linux/arm/entrypoints.txt
@@ -102,6 +102,13 @@ set(TARGET_LIBC_ENTRYPOINTS
 
     # sys/prctl.h entrypoints
     libc.src.sys.prctl.prctl
+
+    # sys/epoll.h entrypoints
+    # Disabled due to epoll_wait syscalls not being available on this platform.
+    # libc.src.sys.epoll.epoll_wait
+    # libc.src.sys.epoll.epoll_pwait
+    # libc.src.sys.epoll.epoll_pwait2
+
 )
 
 set(TARGET_LIBM_ENTRYPOINTS

diff --git a/libc/config/linux/arm/headers.txt b/libc/config/linux/arm/headers.txt
@@ -10,4 +10,7 @@ set(TARGET_PUBLIC_HEADERS
     libc.include.string
     libc.include.strings
     libc.include.search
+
+    # Disabled due to epoll_wait syscalls not being available on this platform.
+    # libc.include.sys_epoll
 )
diff --git a/libc/config/linux/riscv/entrypoints.txt b/libc/config/linux/riscv/entrypoints.txt
@@ -185,6 +185,12 @@ set(TARGET_LIBC_ENTRYPOINTS
     # sys/auxv.h entrypoints
     libc.src.sys.auxv.getauxval
 
+    # sys/epoll.h entrypoints
+    # Disabled due to epoll_wait syscalls not being available on this platform.
+    # libc.src.sys.epoll.epoll_wait
+    # libc.src.sys.epoll.epoll_pwait
+    # libc.src.sys.epoll.epoll_pwait2
+
     # termios.h entrypoints
     libc.src.termios.cfgetispeed
     libc.src.termios.cfgetospeed

diff --git a/libc/config/linux/riscv/headers.txt b/libc/config/linux/riscv/headers.txt
@@ -30,6 +30,8 @@ set(TARGET_PUBLIC_HEADERS
     libc.include.arpa_inet
 
     libc.include.sys_auxv
+    # Disabled due to epoll_wait syscalls not being available on this platform.
+    # libc.include.sys_epoll
     libc.include.sys_ioctl
     libc.include.sys_mman
     libc.include.sys_prctl

diff --git a/libc/config/linux/syscall_numbers.h.inc b/libc/config/linux/syscall_numbers.h.inc
@@ -258,6 +258,10 @@
 #define SYS_epoll_pwait __NR_epoll_pwait
 #endif
 
+#ifdef __NR_epoll_pwait2
+#define SYS_epoll_pwait2 __NR_epoll_pwait2
+#endif
+
 #ifdef __NR_epoll_wait
 #define SYS_epoll_wait __NR_epoll_wait
 #endif

diff --git a/libc/config/linux/x86_64/entrypoints.txt b/libc/config/linux/x86_64/entrypoints.txt
@@ -143,6 +143,11 @@ set(TARGET_LIBC_ENTRYPOINTS
     libc.src.stdio.scanf
     libc.src.stdio.fscanf
 
+    # sys/epoll.h entrypoints
+    libc.src.sys.epoll.epoll_wait
+    libc.src.sys.epoll.epoll_pwait
+    libc.src.sys.epoll.epoll_pwait2
+
     # sys/mman.h entrypoints
     libc.src.sys.mman.madvise
     libc.src.sys.mman.mmap

diff --git a/libc/config/linux/x86_64/headers.txt b/libc/config/linux/x86_64/headers.txt
@@ -30,6 +30,7 @@ set(TARGET_PUBLIC_HEADERS
     libc.include.arpa_inet
 
     libc.include.sys_auxv
+    libc.include.sys_epoll
     libc.include.sys_ioctl
     libc.include.sys_mman
     libc.include.sys_prctl

diff --git a/libc/include/CMakeLists.txt b/libc/include/CMakeLists.txt
@@ -341,6 +341,17 @@ add_gen_header(
     .llvm-libc-macros.sys_auxv_macros
 )
 
+add_gen_header(
+  sys_epoll
+  DEF_FILE sys/epoll.h.def
+  GEN_HDR sys/epoll.h
+  DEPENDS
+    .llvm_libc_common_h
+    .llvm-libc-types.struct_epoll_event
+    .llvm-libc-types.struct_epoll_data
+    .llvm-libc-types.sigset_t
+)
+
 add_gen_header(
   sys_ioctl
   DEF_FILE sys/ioctl.h.def

diff --git a/libc/include/llvm-libc-types/CMakeLists.txt b/libc/include/llvm-libc-types/CMakeLists.txt
@@ -96,3 +96,5 @@ add_header(rpc_opcodes_t HDR rpc_opcodes_t.h)
 add_header(ACTION HDR ACTION.h)
 add_header(ENTRY HDR ENTRY.h)
 add_header(struct_hsearch_data HDR struct_hsearch_data.h)
+add_header(struct_epoll_event HDR struct_epoll_event.h)
+add_header(struct_epoll_data HDR struct_epoll_data.h)
diff --git a/libc/include/llvm-libc-types/struct_epoll_data.h b/libc/include/llvm-libc-types/struct_epoll_data.h
@@ -0,0 +1,21 @@
+//===-- Definition of epoll_data type -------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef __LLVM_LIBC_TYPES_EPOLL_DATA_H__
+#define __LLVM_LIBC_TYPES_EPOLL_DATA_H__
+
+union epoll_data {
+  void *ptr;
+  int fd;
+  __UINT32_TYPE__ u32;
+  __UINT64_TYPE__ u64;
+};
+
+typedef union epoll_data epoll_data_t;
+
+#endif // __LLVM_LIBC_TYPES_EPOLL_DATA_H__
diff --git a/libc/include/llvm-libc-types/struct_epoll_event.h b/libc/include/llvm-libc-types/struct_epoll_event.h
@@ -0,0 +1,19 @@
+//===-- Definition of epoll_event type ------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef __LLVM_LIBC_TYPES_EPOLL_EVENT_H__
+#define __LLVM_LIBC_TYPES_EPOLL_EVENT_H__
+
+#include <llvm-libc-types/struct_epoll_data.h>
+
+typedef struct epoll_event {
+  __UINT32_TYPE__ events;
+  epoll_data_t data;
+} epoll_event;
+
+#endif // __LLVM_LIBC_TYPES_EPOLL_EVENT_H__
diff --git a/libc/include/sys/epoll.h.def b/libc/include/sys/epoll.h.def
@@ -0,0 +1,16 @@
+//===-- Linux header epoll.h ----------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_SYS_EPOLL_H
+#define LLVM_LIBC_SYS_EPOLL_H
+
+#include <__llvm-libc-common.h>
+
+%%public_api()
+
+#endif // LLVM_LIBC_SYS_EPOLL_H
diff --git a/libc/spec/gnu_ext.td b/libc/spec/gnu_ext.td
@@ -238,7 +238,9 @@ def GnuExtensions : StandardSpec<"GNUExtensions"> {
       [], // Macros
       [], // Types
       [], // Enumerations
-      []  // Functions
+      [
+        //TODO: Add getauxval here
+      ]  // Functions
   >;
 
   HeaderSpec SendFile = HeaderSpec<

diff --git a/libc/spec/linux.td b/libc/spec/linux.td
@@ -1,3 +1,8 @@
+def StructEpollEvent : NamedType<"struct epoll_event">;
+def StructEpollEventPtr : PtrType<StructEpollEvent>;
+
+def StructEpollData : NamedType<"struct epoll_data">;
+
 def Linux : StandardSpec<"Linux"> {
   HeaderSpec Errno = HeaderSpec<
       "errno.h",
@@ -137,6 +142,77 @@ def Linux : StandardSpec<"Linux"> {
       []  // Functions
   >;
 
+
+  HeaderSpec SysEpoll = HeaderSpec<
+      "sys/epoll.h",
+      [], // Macros
+      [
+        StructEpollEvent,
+        StructEpollData,
+        SigSetType,
+        StructTimeSpec,
+      ], // Types
+      [], // Enumerations
+      [
+        FunctionSpec<
+          "epoll_create",
+          RetValSpec<IntType>,
+          [
+            ArgSpec<IntType>
+          ]
+        >,
+        FunctionSpec<
+          "epoll_create1",
+          RetValSpec<IntType>,
+          [
+            ArgSpec<IntType>
+          ]
+        >,
+        FunctionSpec<
+          "epoll_ctl",
+          RetValSpec<IntType>,
+          [
+            ArgSpec<IntType>,
+            ArgSpec<IntType>,
+            ArgSpec<IntType>,
+            ArgSpec<StructEpollEventPtr>
+          ]
+        >,
+        FunctionSpec<
+          "epoll_wait",
+          RetValSpec<IntType>,
+          [
+            ArgSpec<IntType>,
+            ArgSpec<StructEpollEventPtr>,
+            ArgSpec<IntType>,
+            ArgSpec<IntType>
+          ]
+        >,
+        FunctionSpec<
+          "epoll_pwait",
+          RetValSpec<IntType>,
+          [
+            ArgSpec<IntType>,
+            ArgSpec<StructEpollEventPtr>,
+            ArgSpec<IntType>,
+            ArgSpec<IntType>,
+            ArgSpec<SigSetPtrType>
+          ]
+        >,
+        FunctionSpec<
+          "epoll_pwait2",
+          RetValSpec<IntType>,
+          [
+            ArgSpec<IntType>,
+            ArgSpec<StructEpollEventPtr>,
+            ArgSpec<IntType>,
+            ArgSpec<ConstStructTimeSpecPtr>,
+            ArgSpec<SigSetPtrType>
+          ]
+        >,
+      ]  // Functions
+  >;
+
   HeaderSpec Signal = HeaderSpec<
       "signal.h",
       [
@@ -181,6 +257,7 @@ def Linux : StandardSpec<"Linux"> {
 
   let Headers = [
     Errno,
+    SysEpoll,
     SysMMan,
     SysPrctl,
     SysRandom,

diff --git a/libc/src/sys/CMakeLists.txt b/libc/src/sys/CMakeLists.txt
@@ -1,4 +1,5 @@
 add_subdirectory(auxv)
+add_subdirectory(epoll)
 add_subdirectory(mman)
 add_subdirectory(random)
 add_subdirectory(resource)

diff --git a/libc/src/sys/epoll/CMakeLists.txt b/libc/src/sys/epoll/CMakeLists.txt
@@ -0,0 +1,24 @@
+if(EXISTS ${CMAKE_CURRENT_SOURCE_DIR}/${LIBC_TARGET_OS})
+  add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/${LIBC_TARGET_OS})
+endif()
+
+add_entrypoint_object(
+  epoll_wait
+  ALIAS
+  DEPENDS
+    .${LIBC_TARGET_OS}.epoll_wait
+)
+
+add_entrypoint_object(
+  epoll_pwait
+  ALIAS
+  DEPENDS
+    .${LIBC_TARGET_OS}.epoll_pwait
+)
+
+add_entrypoint_object(
+  epoll_pwait2
+  ALIAS
+  DEPENDS
+    .${LIBC_TARGET_OS}.epoll_pwait2
+)
diff --git a/libc/src/sys/epoll/epoll_pwait.h b/libc/src/sys/epoll/epoll_pwait.h
@@ -0,0 +1,26 @@
+//===-- Implementation header for epoll_pwait function ----------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_SRC_SYS_EPOLL_EPOLL_PWAIT_H
+#define LLVM_LIBC_SRC_SYS_EPOLL_EPOLL_PWAIT_H
+
+// TODO: Use this include once the include headers are also using quotes.
+// #include "include/llvm-libc-types/sigset_t.h"
+// #include "include/llvm-libc-types/struct_epoll_event.h"
+
+#include <sys/epoll.h>
+
+namespace LIBC_NAMESPACE {
+
+// TODO: sigmask should be nullable
+int epoll_pwait(int epfd, epoll_event *events, int maxevents, int timeout,
+                const sigset_t *sigmask);
+
+} // namespace LIBC_NAMESPACE
+
+#endif // LLVM_LIBC_SRC_SYS_EPOLL_EPOLL_PWAIT_H
diff --git a/libc/src/sys/epoll/epoll_pwait2.h b/libc/src/sys/epoll/epoll_pwait2.h
@@ -0,0 +1,27 @@
+//===-- Implementation header for epoll_pwait2 function ---------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_SRC_SYS_EPOLL_EPOLL_PWAIT2_H
+#define LLVM_LIBC_SRC_SYS_EPOLL_EPOLL_PWAIT2_H
+
+// TODO: Use this include once the include headers are also using quotes.
+// #include "include/llvm-libc-types/sigset_t.h"
+// #include "include/llvm-libc-types/struct_epoll_event.h"
+// #include "include/llvm-libc-types/struct_timespec.h"
+
+#include <sys/epoll.h>
+
+namespace LIBC_NAMESPACE {
+
+// TODO: sigmask and timeout should be nullable
+int epoll_pwait2(int epfd, epoll_event *events, int maxevents,
+                 const timespec *timeout, const sigset_t *sigmask);
+
+} // namespace LIBC_NAMESPACE
+
+#endif // LLVM_LIBC_SRC_SYS_EPOLL_EPOLL_PWAIT2_H