Add klogctl to linux and android

For android, we also add the `KLOG_*` constants. For linux, they are
defined in source but not exported to user space.

(backport <#3777>)
(cherry picked from commit ece907b)

Author: sgasse

libc-test/build.rs

@@ -1656,6 +1656,7 @@ fn test_android(target: &str) {
                "sys/fsuid.h",
                "sys/inotify.h",
                "sys/ioctl.h",
+               "sys/klog.h",
                "sys/mman.h",
                "sys/mount.h",
                "sys/personality.h",
@@ -3433,6 +3434,7 @@ fn test_linux(target: &str) {
                "sys/eventfd.h",
                "sys/file.h",
                "sys/fsuid.h",
+               "sys/klog.h",
                "sys/inotify.h",
                "sys/ioctl.h",
                "sys/ipc.h",

libc-test/semver/android.txt

@@ -1073,6 +1073,17 @@ KEXEC_ON_CRASH
 KEXEC_PRESERVE_CONTEXT
 KEY_CNT
 KEY_MAX
+KLOG_CLOSE
+KLOG_OPEN
+KLOG_READ
+KLOG_READ_ALL
+KLOG_READ_CLEAR
+KLOG_CLEAR
+KLOG_CONSOLE_OFF
+KLOG_CONSOLE_ON
+KLOG_CONSOLE_LEVEL
+KLOG_SIZE_UNREAD
+KLOG_SIZE_BUFFER
 LC_ADDRESS
 LC_ADDRESS_MASK
 LC_ALL
@@ -3341,6 +3352,7 @@ itimerval
 key_t
 kill
 killpg
+klogctl
 lastlog
 lchown
 lconv

libc-test/semver/linux.txt

@@ -3562,6 +3562,7 @@ j1939_filter
 jrand48
 key_t
 killpg
+klogctl
 labs
 lcong48
 lgetxattr

src/unix/linux_like/android/mod.rs

@@ -3523,6 +3523,18 @@ pub const PF_MEMALLOC_PIN: ::c_int = 0x10000000;
 
 pub const PF_SUSPEND_TASK: ::c_int = 0x80000000;
 
+pub const KLOG_CLOSE: ::c_int = 0;
+pub const KLOG_OPEN: ::c_int = 1;
+pub const KLOG_READ: ::c_int = 2;
+pub const KLOG_READ_ALL: ::c_int = 3;
+pub const KLOG_READ_CLEAR: ::c_int = 4;
+pub const KLOG_CLEAR: ::c_int = 5;
+pub const KLOG_CONSOLE_OFF: ::c_int = 6;
+pub const KLOG_CONSOLE_ON: ::c_int = 7;
+pub const KLOG_CONSOLE_LEVEL: ::c_int = 8;
+pub const KLOG_SIZE_UNREAD: ::c_int = 9;
+pub const KLOG_SIZE_BUFFER: ::c_int = 10;
+
 // Most `*_SUPER_MAGIC` constants are defined at the `linux_like` level; the
 // following are only available on newer Linux versions than the versions
 // currently used in CI in some configurations, so we define them here.
@@ -4095,6 +4107,8 @@ extern "C" {
     ) -> ::size_t;
     pub fn fflush_unlocked(stream: *mut ::FILE) -> ::c_int;
     pub fn fgets_unlocked(buf: *mut ::c_char, size: ::c_int, stream: *mut ::FILE) -> *mut ::c_char;
+
+    pub fn klogctl(syslog_type: ::c_int, bufp: *mut ::c_char, len: ::c_int) -> ::c_int;
 }
 
 cfg_if! {

src/unix/linux_like/linux/mod.rs

@@ -5626,6 +5626,8 @@ extern "C" {
         len: ::size_t,
         flags: ::c_uint,
     ) -> ::ssize_t;
+
+    pub fn klogctl(syslog_type: ::c_int, bufp: *mut ::c_char, len: ::c_int) -> ::c_int;
 }
 
 // LFS64 extensions