32-bit Android9 termux bfs_statx emulation via fstatat suggested

[korziner]

32-bit Android9 termux patch suggested

bfs_statx emulation via fstatat

static int bfs_statx(int at_fd, const char *at_path, int at_flags, unsigned int mask, struct statx *buf) {
    // Android9: statx forbidden, using fstatat
    struct stat sb;
    int ret = fstatat(at_fd, at_path, &sb, at_flags);
    if (ret == 0) {
        memset(buf, 0, sizeof(*buf));
        buf->stx_mask = STATX_BASIC_STATS;
        buf->stx_mode = sb.st_mode;
        buf->stx_uid = sb.st_uid;
        buf->stx_gid = sb.st_gid;
        buf->stx_size = sb.st_size;
        buf->stx_blksize = sb.st_blksize;
        buf->stx_blocks = sb.st_blocks;
        buf->stx_atime.tv_sec = sb.st_atime;
        buf->stx_mtime.tv_sec = sb.st_mtime;
        buf->stx_ctime.tv_sec = sb.st_ctime;
        // birthtime leave not filled
    }
    return ret;
}

Bug was as follows:

~/.../deb/bfs-4.1 $ strace -f bin/bfs 2>&1 | tail -55                                                               
[pid 20021] close(1014)                 = -1 EBADF (Bad file descriptor)
[pid 20021] close(1015)                 = -1 EBADF (Bad file descriptor)
[pid 20021] close(1016)                 = -1 EBADF (Bad file descriptor)
[pid 20021] close(1017)                 = -1 EBADF (Bad file descriptor)
[pid 20021] close(1018)                 = -1 EBADF (Bad file descriptor)
[pid 20021] close(1019)                 = -1 EBADF (Bad file descriptor)
[pid 20021] close(1020)                 = -1 EBADF (Bad file descriptor)
[pid 20021] close(1021)                 = -1 EBADF (Bad file descriptor)
[pid 20021] close(1022)                 = -1 EBADF (Bad file descriptor)
[pid 20021] close(1023)                 = -1 EBADF (Bad file descriptor)
[pid 20021] openat(AT_FDCWD, "/dev/null", O_RDWR|O_LARGEFILE) = 0
[pid 20021] dup3(0, 1, 0)               = 1
[pid 20021] dup3(0, 2, 0)               = 2
[pid 20021] pipe2([3, 4], 0)            = 0
[pid 20021] clone(child_stack=NULL, flags=0strace: Process 20022 attached
) = 20022
[pid 20022] gettid( <unfinished ...>
[pid 20021] close(4 <unfinished ...>
[pid 20022] <... gettid resumed>)       = 20022
[pid 20021] <... close resumed>)        = 0
[pid 20022] dup3(4, 1, 0 <unfinished ...>
[pid 20021] read(3 <unfinished ...>
[pid 20022] <... dup3 resumed>)         = 1
[pid 20022] close(3)                    = 0
[pid 20022] close(4)                    = 0
[pid 20022] capget({version=_LINUX_CAPABILITY_VERSION_3, pid=0}, {effective=0, permitted=0, inheritable=0}) = 0
[pid 20022] execve("/system/bin/crash_dump32", ["crash_dump32", "20020", "20021", "1"], 0xbe91756c /* 38 vars */) = -1 EPERM (Operation not permitted)
[pid 20022] --- SIGSEGV {si_signo=SIGSEGV, si_code=SEGV_ACCERR, si_addr=0xb532bf40} ---
[pid 20022] +++ killed by SIGSEGV +++
[pid 20021] <... read resumed>, "", 4)  = 0
[pid 20021] socket(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0) = 4
[pid 20021] connect(4, {sa_family=AF_UNIX, sun_path="/dev/socket/logdw"}, 110) = 0
[pid 20021] clock_gettime(CLOCK_REALTIME, {tv_sec=1776604893, tv_nsec=825753319}) = 0
[pid 20021] writev(4, [{iov_base="\4", iov_len=1}, {iov_base="4N", iov_len=2}, {iov_base="\335\326\344i\347\37671", iov_len=8}, {iov_base="\7", iov_len=1}, {iov_base="libc\0", iov_len=5}, {iov_base="crash_dump helper failed to exec"..., iov_len=33}], 6) = 50
[pid 20021] close(4)                    = 0
[pid 20021] close(3)                    = 0
[pid 20021] wait4(20022, 0xb532cf88, 0, NULL) = -1 ECHILD (No child processes)
[pid 20021] socket(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0) = 3
[pid 20021] connect(3, {sa_family=AF_UNIX, sun_path="/dev/socket/logdw"}, 110) = 0
[pid 20021] clock_gettime(CLOCK_REALTIME, {tv_sec=1776604893, tv_nsec=829694882}) = 0
[pid 20021] writev(3, [{iov_base="\4", iov_len=1}, {iov_base="4N", iov_len=2}, {iov_base="\335\326\344i\242#t1", iov_len=8}, {iov_base="\7", iov_len=1}, {iov_base="libc\0", iov_len=5}, {iov_base="failed to wait for crash_dump he"..., iov_len=57}], 6) = 74
[pid 20021] close(3)                    = 0
[pid 20021] exit(0)                     = ?
[pid 20020] futex(NULL, FUTEX_WAIT, 20021, NULL) = 4
[pid 20021] +++ exited with 0 +++
prctl(0 /* PR_??? */, 0x1, 0x4e35, 0, 0) = 31
sigaction(0, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=SA_RESTORER|SA_RESTART, sa_restorer=0xb53add70}, {sa_handler=SIG_DFL, sa_mask=[TRAP FPE SEGV USR2 PIPE STKFLT CHLD CONT TTIN TTOU XFSZ PROF IO PWR RTMIN], sa_flags=SA_RESTORER|SA_RESTART|SA_RESETHAND|SA_SIGINFO|SA_NOCLDSTOP|0x21358098, sa_restorer=0xb53add7c}) = 31
sigaction(0, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=SA_RESTORER|SA_RESTART, sa_restorer=0xb53add70}, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=SA_RESTORER|SA_RESTART, sa_restorer=0xb53add70}) = 0
getpid()                                = 526046578
gettid()                                = 20020
rt_tgsigqueueinfo(0, 20020, SIGSYS, {si_signo=SIGSYS, si_code=SYS_SECCOMP, si_call_addr=0xb50aed6c, si_syscall=__NR_statx, si_arch=AUDIT_ARCH_ARM}) = 0
statx(1, "", AT_STATX_SYNC_AS_STAT|AT_NO_AUTOMOUNT|AT_EMPTY_PATH, STATX_ALL|STATX_MNT_ID|STATX_MNT_ID_UNIQUE <unfinished ...>
--- SIGSYS {si_signo=SIGSYS, si_code=SYS_SECCOMP, si_call_addr=0xb50aed6c, si_syscall=397, si_arch=0 /* AUDIT_ARCH_??? */} ---
<... statx resumed> <unfinished ...>)   = ?
+++ killed by SIGSYS +++
~/.../deb/bfs-4.1 $ bin/bfs . -maxdepth 1
Bad system call            bin/bfs . -maxdepth 1

After fix:

~/.../deb/bfs-4.1 $ nano src/stat.c

~/.../deb/bfs-4.1 $ make clean;CFLAGS="-mfpu=neon -O3 -Wno-implicit-function-declaration -D_GNU_SOURCE" ./configure 
[ RM ] bin obj
[ GEN] gen/vars.mk
[ CC ] build/empty.c                   ✔
[ CC ] flags/std.c                     ✔
[ CC ] flags/pthread.c                 ✔
[ CC ] flags/Wformat.c                 ✔
[ CC ] flags/bind-now.c                ✔
[ CC ] flags/deps.c                    ✔
[ CC ] flags/Wimplicit-fallthrough.c   ✔
[ CC ] flags/Wmissing-decls.c          ✔
[ CC ] flags/Wimplicit.c               ✔
[ CC ] flags/Wshadow.c                 ✔
[ CC ] flags/Wmissing-var-decls.c      ✔
[ CC ] flags/Wstrict-prototypes.c      ✔
[ CC ] flags/Wsign-compare.c           ✔
[ CC ] flags/Wundef-prefix.c           ✔
[ GEN] gen/flags.mk
[ CC ] with/libcap.c                   ✘
[ CC ] with/liburing.c                 ✘
[ CC ] with/libselinux.c               ✘
[ CC ] with/libacl.c                   ✔
[ CC ] with/oniguruma.c                ✔
[ GEN] gen/pkgs.mk
[ GEN] gen/config.mk
[ CC ] has/--st-birthtim.c             ✘
[ CC ] has/_Fork.c                     ✘
[ CC ] has/builtin-riscv-pause.c       ✘
[ CC ] has/acl-is-trivial-np.c         ✘
[ CC ] has/acl-trivial.c               ✘
[ CC ] has/acl-get-entry.c             ✔
[ CC ] has/acl-get-file.c              ✔
[ CC ] has/acl-get-tag-type.c          ✔
[ CC ] has/confstr.c                   ✘
[ CC ] has/extattr-get-link.c          ✘
[ CC ] has/extattr-get-file.c          ✘
[ CC ] has/extattr-list-file.c         ✘
[ CC ] has/extattr-list-link.c         ✘
[ CC ] has/dprintf.c                   ✔
[ CC ] has/fdclosedir.c                ✘
[ CC ] has/getdents.c                  ✘
[ CC ] has/getdents64.c                ✘
[ CC ] has/getmntent-2.c               ✘
[ CC ] has/getmntinfo.c                ✘
[ CC ] has/io-uring-max-workers.c      ✘
[ CC ] has/getprogname-gnu.c           ✘
[ CC ] has/getmntent-1.c               ✔
[ CC ] has/getdents64-syscall.c        ✔
[ CC ] has/getprogname.c               ✔
[ CC ] has/pipe2.c                     ✔
[ CC ] has/posix-getdents.c            ✘
[ CC ] has/posix-spawn-addfchdir.c     ✘
[ CC ] has/posix-spawn-addfchdir-np.c  ✘
[ CC ] has/pthread-set-name-np.c       ✘
[ CC ] has/pragma-nounroll.c           ✔
[ CC ] has/pthread-setname-np.c        ✔
[ CC ] has/sched-getaffinity.c         ✔
[ CC ] has/st-acmtimespec.c            ✘
[ CC ] has/st-birthtim.c               ✘
[ CC ] has/st-flags.c                  ✘
[ CC ] has/st-acmtim.c                 ✔
[ CC ] has/st-birthtimespec.c          ✘
[ CC ] has/statx.c                     ✘
[ CC ] has/statx-syscall.c             ✔
[ CC ] has/strerror-l.c                ✔
[ CC ] has/string-to-flags.c           ✘
[ CC ] has/strerror-r-posix.c          ✘
[ CC ] has/strtofflags.c               ✘
[ CC ] has/strerror-r-gnu.c            ✔
[ CC ] has/tcgetwinsize.c              ✔
[ CC ] has/tcsetwinsize.c              ✔
[ CC ] has/timegm.c                    ✔
[ CC ] has/timer-create.c              ✔
[ CC ] has/uselocale.c                 ✔
[ CC ] has/tm-gmtoff.c                 ✔
[ GEN] gen/config.h

~/.../deb/bfs-4.1 $ CFLAGS="-mfpu=neon -O3 -Wno-implicit-function-declaration -D_GNU_SOURCE" make -j7               
[ CC ] src/bar.c
[ CC ] src/main.c
[ CC ] src/alloc.c
[ CC ] src/bftw.c
[ CC ] src/bfstd.c
[ CC ] src/color.c
[ CC ] src/ctx.c
[ CC ] src/diag.c
[ CC ] src/dir.c
[ CC ] src/dstring.c
[ CC ] src/eval.c
[ CC ] src/exec.c
[ CC ] src/expr.c
[ CC ] src/fsade.c
[ CC ] src/ioq.c
[ CC ] src/mtab.c
[ CC ] src/opt.c
[ CC ] src/parse.c
[ CC ] src/printf.c
[ CC ] src/pwcache.c
[ CC ] src/sighook.c
[ CC ] src/stat.c
[ CC ] src/thread.c
[ CC ] src/typo.c
[ CC ] src/trie.c
[ CC ] src/xregex.c
[ CC ] src/xspawn.c
[ CC ] src/xtime.c
[ CC ] src/version.c
[ LD ] bin/bfs
~/.../deb/bfs-4.1 $ bin/bfs . -maxdepth 1
.
./LICENSE
./Makefile
./README.md
./bench
./build
./completions
./configure
./docs
./src
./tests
./gen
./obj
./bin

[tavianator]

Huh, that's quite annoying that it kills you instead of just returning ENOSYS. I see libuv ran into this too: libuv/libuv#2282

But also, Android 9 is 8 years old. Does this affect any newer versions?

I'm still willing to include a patch because it should be very simple, one second...

[korziner]

Does not affect my 64-bit android 11.

But.. if we try to optimise perf, then let go small and minimal

Green movement imperative suggest us to use our old smartphones, of which armhf neon arch is capable to run modern software, e.g. train neuro networks.

[tavianator]

Fixed with the latest commit (I think; I don't have Android 9 around to test). You should be able to build like this:

$ ./configure CFLAGS="-mfpu=neon -O3 -Wno-implicit-function-declaration -D_GNU_SOURCE"
$ make -j7

i.e. without repeating CFLAGS=.... make clean is also unnecessary, it will rebuild everything if you run ./configure.