Re: Android NDK r26 and utmpx

[Bruno Haible]

Hi Po Lu,

> utmpx.h is provided by this new release of the Android NDK, defining
> functions as nonfunctional as utmp.h does.

So, HAVE_UTMPX_H now is 1.

And utmpname exists but utmpxname does not exist. Therefore UTMP_NAME_FUNCTION
is no longer defined.

> The more pressing problem is that its presence suppresses the definition
> of UTMP_NAME_FUNCTION when a program is built with an __ANDROID_API__
> lower than 34, where the utmpx* series of functions were introduced,
> because the conditional for HAVE_UTMPX_H in readutmp.h does not search
> for a `utmpname' function if `utmpxname' is unavailable, with the result
> that get_android_boot_time is never invoked.  Here are the relevant
> portions of config.log:
> 
> configure:9462: checking for utmpx.h
> configure:9462: 
> /opt/android/ndk/android-ndk-r26/toolchains/llvm/prebuilt/linux-x86_64/bin/aarch64-linux-android22-clang
>  -c -O2 -g3 -Werror=implicit-function-declaration  conftest.c >&5
> configure:9462: $? = 0
> configure:9462: result: yes
> 
> configure:16416: 
> /opt/android/ndk/android-ndk-r26/toolchains/llvm/prebuilt/linux-x86_64/bin/aarch64-linux-android22-clang
>  -o conftest -O2 -g3 -Werror=implicit-function-declaration     conftest.c  
> >&5 
> ld.lld: error: undefined symbol: utmpxname
> >>> referenced by conftest.c:116
> >>>               /tmp/conftest-c4f4cf.o:(main)
> >>> did you mean: utmpname
> >>> defined in: 
> >>> /opt/android/ndk/android-ndk-r26/toolchains/llvm/prebuilt/linux-x86_64/bin/../sysroot/usr/lib/aarch64-linux-android/22/libc.so
> 
> I will install a workaround in Emacs, but it ought to be fixed at the
> source.

This patch should fix it, in the simplest possible way. Committing it.


2024-01-21  Bruno Haible  <bruno@clisp.org>

        readutmp, boot-time: Port to Android NDK r26.
        Reported by Po Lu <luangruo@yahoo.com> in
        <https://lists.gnu.org/archive/html/bug-gnulib/2024-01/msg00063.html>.
        * lib/readutmp.h: Update comments.
        (UTMP_NAME_FUNCTION): Define as a no-op for Android with HAVE_UTMPX_H.

diff --git a/lib/readutmp.h b/lib/readutmp.h
index b62eb3beaa..dcfd44dbbc 100644
--- a/lib/readutmp.h
+++ b/lib/readutmp.h
@@ -114,21 +114,21 @@ enum { UT_HOST_SIZE = -1 };
 
      Field        Type                       Platforms
      ----------   ------                     ---------
-   ⎡ ut_user      char[]                     glibc, musl, macOS, FreeBSD, AIX, 
HP-UX, IRIX, Solaris, Cygwin
+   ⎡ ut_user      char[]                     glibc, musl, macOS, FreeBSD, AIX, 
HP-UX, IRIX, Solaris, Cygwin, Android
    ⎣ ut_name      char[]                     NetBSD, Minix
-     ut_id        char[]                     glibc, musl, macOS, FreeBSD, 
NetBSD, Minix, AIX, HP-UX, IRIX, Solaris, Cygwin
-     ut_line      char[]                     glibc, musl, macOS, FreeBSD, 
NetBSD, Minix, AIX, HP-UX, IRIX, Solaris, Cygwin
-     ut_pid       pid_t                      glibc, musl, macOS, FreeBSD, 
NetBSD, Minix, AIX, HP-UX, IRIX, Solaris, Cygwin
-     ut_type      short                      glibc, musl, macOS, FreeBSD, 
NetBSD, Minix, AIX, HP-UX, IRIX, Solaris, Cygwin
-   ⎡ ut_tv        struct                     glibc, musl, macOS, FreeBSD, 
NetBSD, Minix, AIX, HP-UX, IRIX, Solaris, Cygwin
+     ut_id        char[]                     glibc, musl, macOS, FreeBSD, 
NetBSD, Minix, AIX, HP-UX, IRIX, Solaris, Cygwin, Android
+     ut_line      char[]                     glibc, musl, macOS, FreeBSD, 
NetBSD, Minix, AIX, HP-UX, IRIX, Solaris, Cygwin, Android
+     ut_pid       pid_t                      glibc, musl, macOS, FreeBSD, 
NetBSD, Minix, AIX, HP-UX, IRIX, Solaris, Cygwin, Android
+     ut_type      short                      glibc, musl, macOS, FreeBSD, 
NetBSD, Minix, AIX, HP-UX, IRIX, Solaris, Cygwin, Android
+   ⎡ ut_tv        struct                     glibc, musl, macOS, FreeBSD, 
NetBSD, Minix, AIX, HP-UX, IRIX, Solaris, Cygwin, Android
    ⎢              { tv_sec; tv_usec; }
    ⎣ ut_time      time_t                     Cygwin
-     ut_host      char[]                     glibc, musl, macOS, FreeBSD, 
NetBSD, Minix, AIX, HP-UX, IRIX, Solaris, Cygwin
-     ut_exit      struct                     glibc, musl, NetBSD, Minix, 
HP-UX, IRIX, Solaris
+     ut_host      char[]                     glibc, musl, macOS, FreeBSD, 
NetBSD, Minix, AIX, HP-UX, IRIX, Solaris, Cygwin, Android
+     ut_exit      struct                     glibc, musl, NetBSD, Minix, 
HP-UX, IRIX, Solaris, Android
                   { e_termination; e_exit; }
-     ut_session   [long] int                 glibc, musl, NetBSD, Minix, IRIX, 
Solaris
+     ut_session   [long] int                 glibc, musl, NetBSD, Minix, IRIX, 
Solaris, Android
    ⎡ ut_addr      [long] int                 HP-UX, Cygwin
-   ⎢ ut_addr_v6   [u]int[4]                  glibc, musl
+   ⎢ ut_addr_v6   [u]int[4]                  glibc, musl, Android
    ⎣ ut_ss        struct sockaddr_storage    NetBSD, Minix
  */
 
@@ -177,6 +177,10 @@ struct utmpx32
 #  define UTMP_NAME_FUNCTION utmpxname
 # elif defined UTXDB_ACTIVE /* FreeBSD */
 #  define UTMP_NAME_FUNCTION(x) setutxdb (UTXDB_ACTIVE, x)
+# elif defined __ANDROID__ /* Android */
+/* As of Android NDK r26, the getutxent, setutxent functions are no-ops.
+   Therefore we can ignore the file name.  */
+#  define UTMP_NAME_FUNCTION(x) ((void) (x))
 # endif
 
 #elif HAVE_UTMP_H