@danobi Seems all is well. please review. thanks.

Can we create a test for this?

Can we create a test for this?

Is this necessary? This PR only solves the error when /usr/bin/sleep and /bin/sleep are the same executable file. How should this situation be deployed in the CICD environment?

$ ls -l /bin
lrwxrwxrwx. 1 root root 7 Aug 10  2021 /bin -> usr/bin
$ realpath /bin/sleep
/usr/bin/sleep

This problem may not exist in different environments (including CICD), so I suggest not to add a test case. What do you think?

@viktormalik Or we can create a /usr/sbin/sleep symbolic link to /usr/bin/sleep, like:

TEST(childproc, multi_exe_link_match)
{
   // Create /usr/sbin/sleep -> /usr/bin/sleep
   // Test bpftrace -e '...' sleep 5
}

However, i still think it's not necessary to add this test case.

I just force push a modification. There may be worse cases like

  $ realpath /usr/bin/ping /bin/ping /usr/sbin/ping /sbin/ping
  /usr/bin/ping
  /usr/bin/ping
  /usr/bin/ping
  /usr/bin/ping

  $ sudo bpftrace -e 'kprobe:do_nanosleep { printf("%d sleeping\n", pid); }' -c 'ping -c 4 0'
  ERROR: Failed to fork child: path 'ping' must refer to a unique binary but matched 4 binaries

So instead of using case 2 to solve it, it is better to use std::unordered_set<std::string>+abs_path() to solve this problem.

The fix looks good to me. But I agree with Viktor -- test here would be good. But rather than depend on CI environment (which is not reliable like you mention), we could create a tempdir and then populate it with a an executable shell script and some symlinks to it. I think that should be reliable.

The fix looks good to me. But I agree with Viktor -- test here would be good. But rather than depend on CI environment (which is not reliable like you mention), we could create a tempdir and then populate it with a an executable shell script and some symlinks to it. I think that should be reliable.

I have a question, shall we add a test example in C, such as the following code in tests/child.cpp:

TEST(childproc, match_multi_exe)
{
  char path[] = "rootfs/";
  // make temp rootfs directory
  // make /usr/bin/ under rootfs
  // create tmp shell script "sleep.sh" (with x permission)
  // create link: /bin -> /usr/bin
  // put the rootfs/usr/bin and rootfs/bin to env
  // THEN, test sleep.sh
}

right? I'm not sure if my idea is accurate, if not, please give me some advice. thanks.

Yeah that looks right to me

Yeah that looks right to me

OK, I'll try it.

@danobi @viktormalik I just add test childproc.multi_exec_match, please review.

        $ sudo ./tests/bpftrace_test --gtest_filter=childproc.multi_exec_match
        Note: Google Test filter = childproc.multi_exec_match
        [==========] Running 1 test from 1 test suite.
        [----------] Global test environment set-up.
        [----------] 1 test from childproc
        [ RUN      ] childproc.multi_exec_match
        [       OK ] childproc.multi_exec_match (10 ms)
        [----------] 1 test from childproc (10 ms total)
    
        [----------] Global test environment tear-down
        [==========] 1 test from 1 test suite ran. (10 ms total)
        [  PASSED  ] 1 test.