libc: Introduce calls to sysconf to get page size.

sysconf(_SC_PAGESIZE) is implemented now.

Reviewers: michaelrj-google, aaronmondal, rupprecht, keith

Reviewed By: michaelrj-google

Pull Request: #163462

Author: pcc

libc/test/src/sys/mman/linux/CMakeLists.txt

@@ -99,6 +99,7 @@ add_libc_unittest(
     libc.src.sys.mman.mincore
     libc.src.sys.mman.mlock
     libc.src.sys.mman.munlock
+    libc.src.unistd.sysconf
     libc.test.UnitTest.ErrnoCheckingTest
     libc.test.UnitTest.ErrnoSetterMatcher
 )
@@ -123,6 +124,7 @@ add_libc_unittest(
     libc.src.sys.mman.mlockall
     libc.src.sys.mman.munlockall
     libc.src.sys.resource.getrlimit
+    libc.src.unistd.sysconf
     libc.src.__support.OSUtil.osutil
     libc.test.UnitTest.ErrnoCheckingTest
     libc.test.UnitTest.ErrnoSetterMatcher
@@ -144,6 +146,7 @@ add_libc_unittest(
     libc.src.sys.mman.mincore
     libc.src.sys.mman.mlock
     libc.src.sys.mman.munlock
+    libc.src.unistd.sysconf
     libc.test.UnitTest.ErrnoCheckingTest
     libc.test.UnitTest.ErrnoSetterMatcher
 )
@@ -165,6 +168,7 @@ add_libc_unittest(
     libc.src.sys.mman.munmap
     libc.src.fcntl.open
     libc.src.unistd.close
+    libc.src.unistd.sysconf
 )
 
 add_libc_unittest(

libc/test/src/sys/mman/linux/mincore_test.cpp

@@ -12,6 +12,7 @@
 #include "src/sys/mman/mmap.h"
 #include "src/sys/mman/munlock.h"
 #include "src/sys/mman/munmap.h"
+#include "src/unistd/sysconf.h"
 #include "test/UnitTest/ErrnoCheckingTest.h"
 #include "test/UnitTest/ErrnoSetterMatcher.h"
 #include "test/UnitTest/Test.h"
@@ -20,8 +21,7 @@ using LIBC_NAMESPACE::testing::ErrnoSetterMatcher::Fails;
 using LIBC_NAMESPACE::testing::ErrnoSetterMatcher::Succeeds;
 using LlvmLibcMincoreTest = LIBC_NAMESPACE::testing::ErrnoCheckingTest;
 
-// TODO: Replace with sysconf call once the function is properly implemented.
-constexpr size_t PAGE_SIZE = 4096;
+const size_t PAGE_SIZE = LIBC_NAMESPACE::sysconf(_SC_PAGESIZE);
 
 TEST_F(LlvmLibcMincoreTest, UnMappedMemory) {
   unsigned char vec;

libc/test/src/sys/mman/linux/mlock_test.cpp

@@ -22,14 +22,14 @@
 #include "src/sys/mman/munlockall.h"
 #include "src/sys/mman/munmap.h"
 #include "src/sys/resource/getrlimit.h"
+#include "src/unistd/sysconf.h"
 #include "test/UnitTest/ErrnoCheckingTest.h"
 #include "test/UnitTest/ErrnoSetterMatcher.h"
 #include "test/UnitTest/Test.h"
 
 #include <sys/syscall.h>
 
-// TODO: Replace with sysconf call once the function is properly implemented.
-constexpr size_t PAGE_SIZE = 4096;
+const size_t PAGE_SIZE = LIBC_NAMESPACE::sysconf(_SC_PAGESIZE);
 
 using namespace LIBC_NAMESPACE::testing::ErrnoSetterMatcher;
 using LlvmLibcMlockTest = LIBC_NAMESPACE::testing::ErrnoCheckingTest;

libc/test/src/sys/mman/linux/msync_test.cpp

@@ -11,12 +11,12 @@
 #include "src/sys/mman/msync.h"
 #include "src/sys/mman/munlock.h"
 #include "src/sys/mman/munmap.h"
+#include "src/unistd/sysconf.h"
 #include "test/UnitTest/ErrnoCheckingTest.h"
 #include "test/UnitTest/ErrnoSetterMatcher.h"
 #include "test/UnitTest/Test.h"
 
-// TODO: Replace with sysconf call once the function is properly implemented.
-constexpr size_t PAGE_SIZE = 4096;
+const size_t PAGE_SIZE = LIBC_NAMESPACE::sysconf(_SC_PAGESIZE);
 
 using namespace LIBC_NAMESPACE::testing::ErrnoSetterMatcher;
 using LlvmLibcMsyncTest = LIBC_NAMESPACE::testing::ErrnoCheckingTest;

libc/test/src/sys/mman/linux/remap_file_pages_test.cpp

@@ -11,15 +11,15 @@
 #include "src/sys/mman/munmap.h"
 #include "src/sys/mman/remap_file_pages.h"
 #include "src/unistd/close.h"
+#include "src/unistd/sysconf.h"
 #include "test/UnitTest/ErrnoCheckingTest.h"
 #include "test/UnitTest/ErrnoSetterMatcher.h"
 #include "test/UnitTest/Test.h"
 
 #include <sys/mman.h>
 #include <sys/stat.h> // For S_IRWXU
 
-// TODO: Replace with sysconf call once the function is properly implemented.
-constexpr size_t PAGE_SIZE = 4096;
+const size_t PAGE_SIZE = LIBC_NAMESPACE::sysconf(_SC_PAGESIZE);
 
 using LIBC_NAMESPACE::testing::ErrnoSetterMatcher::Fails;
 using LIBC_NAMESPACE::testing::ErrnoSetterMatcher::Succeeds;

utils/bazel/llvm-project-overlay/libc/BUILD.bazel

@@ -1501,6 +1501,21 @@ libc_support_library(
     ],
 )
 
+libc_support_library(
+    name = "__support_osutil_linux_auxv",
+    hdrs = ["src/__support/OSUtil/linux/auxv.h"],
+    target_compatible_with = select({
+        "@platforms//os:linux": [],
+        "//conditions:default": ["@platforms//:incompatible"],
+    }),
+    deps = [
+        ":__support_common",
+        ":__support_osutil_syscall",
+        ":__support_threads_callonce",
+        ":hdr_fcntl_macros",
+    ],
+)
+
 libc_support_library(
     name = "__support_osutil_vdso",
     hdrs = [
@@ -6336,6 +6351,19 @@ libc_function(
     ],
 )
 
+# WARNING: NOT FULLY IMPLEMENTED, FOR TESTING USE ONLY
+libc_function(
+    name = "sysconf",
+    srcs = ["src/unistd/linux/sysconf.cpp"],
+    hdrs = ["src/unistd/sysconf.h"],
+    deps = [
+        ":__support_common",
+        ":__support_osutil_linux_auxv",
+        ":errno",
+        ":hdr_unistd_macros",
+    ],
+)
+
 libc_function(
     name = "write",
     srcs = ["src/unistd/linux/write.cpp"],

utils/bazel/llvm-project-overlay/libc/test/src/sys/mman/BUILD.bazel

@@ -30,6 +30,7 @@ libc_test(
         "//libc:mmap",
         "//libc:munlock",
         "//libc:munmap",
+        "//libc:sysconf",
     ],
 )
 
@@ -48,6 +49,7 @@ libc_test(
         "//libc:munlock",
         "//libc:munlockall",
         "//libc:munmap",
+        "//libc:sysconf",
     ],
 )
 
@@ -89,6 +91,7 @@ libc_test(
         "//libc:msync",
         "//libc:munlock",
         "//libc:munmap",
+        "//libc:sysconf",
     ],
 )
 
@@ -111,6 +114,7 @@ libc_test(
         "//libc:munmap",
         "//libc:open",
         "//libc:remap_file_pages",
+        "//libc:sysconf",
     ],
 )