crash

[enenH]

On Android

int main(int argc, char** argv) {
auto obuf = check_output({"ls", "-l"});
printf( "obuf:%s\n", obuf.buf.data());
return 0;
}

fdsan: attempted to close file descriptor 5, expected to be unowned, actually owned by FILE* 0x75c06f90b0

[enenH]

06-29 13:58:55.841 12102 12102 F DEBUG : pid: 12097, tid: 12097, name: entry >>> /data/local/tmp/entry <<<
06-29 13:58:55.841 12102 12102 F DEBUG : uid: 0
06-29 13:58:55.841 12102 12102 F DEBUG : tagged_addr_ctrl: 0000000000000001 (PR_TAGGED_ADDR_ENABLE)
06-29 13:58:55.841 12102 12102 F DEBUG : pac_enabled_keys: 000000000000000f (PR_PAC_APIAKEY, PR_PAC_APIBKEY, PR_PAC_APDAKEY, PR_PAC_APDBKEY)
06-29 13:58:55.841 12102 12102 F DEBUG : signal 6 (SIGABRT), code -1 (SI_QUEUE), fault addr --------
06-29 13:58:55.841 12102 12102 F DEBUG : Abort message: 'fdsan: attempted to close file descriptor 5, expected to be unowned, actually owned by FILE* 0x7bc28f90b0'
06-29 13:58:55.841 12102 12102 F DEBUG : x0 0000000000000000 x1 0000000000002f41 x2 0000000000000006 x3 0000007fea15f340
06-29 13:58:55.841 12102 12102 F DEBUG : x4 0080808080808080 x5 0080808080808080 x6 0080808080808080 x7 8080808080808080
06-29 13:58:55.841 12102 12102 F DEBUG : x8 00000000000000f0 x9 56b4ac894a1e475c x10 0000000000000002 x11 7f7f7f7f7f7f7f7f
06-29 13:58:55.841 12102 12102 F DEBUG : x12 0101010101010101 x13 000000007fffffff x14 0000000000061e00 x15 0000000000000010
06-29 13:58:55.841 12102 12102 F DEBUG : x16 0000007c4ddd1a68 x17 0000007c4ddaa710 x18 0000007c6dfc8000 x19 0000000000002f41
06-29 13:58:55.841 12102 12102 F DEBUG : x20 0000000000002f41 x21 0000007c6d006010 x22 0000000000000003 x23 0000007fea15f138
06-29 13:58:55.841 12102 12102 F DEBUG : x24 0000007fea15f430 x25 0000007fea15f0b0 x26 0000007fea15f070 x27 ffffff80ffffffc8
06-29 13:58:55.841 12102 12102 F DEBUG : x28 0000000000000000 x29 0000007fea15f3d0
06-29 13:58:55.841 12102 12102 F DEBUG : lr 0000007c4dd56394 sp 0000007fea15eff0 pc 0000007c4dd563b8 pst 0000000000001000
06-29 13:58:55.841 12102 12102 F DEBUG : backtrace:
06-29 13:58:55.841 12102 12102 F DEBUG : #00 pc 00000000000913b8 /apex/com.android.runtime/lib64/bionic/libc.so (fdsan_error(char const*, ...)+552) (BuildId: 95768e541c682c20709fc11df6431f16)
06-29 13:58:55.841 12102 12102 F DEBUG : #1 pc 00000000000910c4 /apex/com.android.runtime/lib64/bionic/libc.so (android_fdsan_close_with_tag+724) (BuildId: 95768e541c682c20709fc11df6431f16)
06-29 13:58:55.841 12102 12102 F DEBUG : #2 pc 0000000000091820 /apex/com.android.runtime/lib64/bionic/libc.so (close+16) (BuildId: 95768e541c682c20709fc11df6431f16)
06-29 13:58:55.841 12102 12102 F DEBUG : #3 pc 000000000020c64c /data/local/tmp/entry (subprocess::Popen::execute_process()+1220) (BuildId: 908c3bd30562abb0d7f0e94572fc90a5488867df)
06-29 13:58:55.841 12102 12102 F DEBUG : #4 pc 000000000021d93c /data/local/tmp/entry (subprocess::Popen::Popensubprocess::output(std::initializer_list<char const*>, subprocess::output&&)+400) (BuildId: 908c3bd30562abb0d7f0e94572fc90a5488867df)
06-29 13:58:55.841 12102 12102 F DEBUG : #5 pc 000000000021d620 /data/local/tmp/entry (subprocess::Buffer subprocess::detail::check_output_impl<std::initializer_list<char const*> >(std::initializer_list<char const*>&)+108) (BuildId: 908c3bd30562abb0d7f0e94572fc90a5488867df)
06-29 13:58:55.841 12102 12102 F DEBUG : #6 pc 00000000001e6f28 /data/local/tmp/entry (subprocess::Buffer subprocess::check_output<>(std::initializer_list<char const*>)+44) (BuildId: 908c3bd30562abb0d7f0e94572fc90a5488867df)
06-29 13:58:55.841 12102 12102 F DEBUG : #7 pc 00000000001e6e58 /data/local/tmp/entry (main+96) (BuildId: 908c3bd30562abb0d7f0e94572fc90a5488867df)
06-29 13:58:55.841 12102 12102 F DEBUG : #8 pc 0000000000085240 /apex/com.android.runtime/lib64/bionic/libc.so (__libc_init+96) (BuildId: 95768e541c682c20709fc11df6431f16)

[arun11299]

@enenH Thank you for reporting.

My guess is that we need to close the FILE pointers (input_, output_, error_) as well before close the file descriptors directly in close_parent_fds function.

Are you comfortable to try this and check again ? My valgrind with fd tracking did not give any issues on ubuntu.

Thank you.

[enenH]

void close_parent_fds()
{
if(input()) fclose(input());
if(output()) fclose(output());
if(error()) fclose(error());
if (write_to_child_ != -1) close(write_to_child_);
if (read_from_child_ != -1) close(read_from_child_);
if (err_read_ != -1) close(err_read_);
}

Same problem

[arun11299]

Thanks for trying it. Is the fdsan error exactly the same or is there any difference ?

[enenH]

cpp-subprocess/subprocess.hpp

Line 1637 in 4025693

close(err_rd_pipe);

This code is causing the crash. The following code works fine.
auto f=fdopen(err_rd_pipe, "r"); int read_bytes = util::read_atmost_n(f, err_buf, SP_MAX_ERR_BUF_SIZ); if (f) fclose( f); close(err_rd_pipe);
If fdopen() is successful, you must use fclose() to close the stream and file

[arun11299]

Great! If you can open a PR I would be happy to merge it.