open() ignores trailing slash on regular files (no ENOTDIR)

[Ryan2026R]

Version of emscripten/emsdk:

5.0.6

POSIX says a trailing slash implies directory access: open("file/", O_RDONLY) must fail with ENOTDIR when file is a regular file. Under MEMFS the call succeeds and returns a valid fd.

Failing command line in full:

$ emcc -O0 -Wall trailing.c -o a.out.js
$ node a.out.js
open(file/): fd=3 errno=0

The same program on native Linux prints open(file/): fd=-1 errno=20.

Example code snippet:

#include <fcntl.h>
#include <unistd.h>
#include <sys/stat.h>
#include <stdio.h>
#include <errno.h>

int main(void) {
    mkdir("/tmp/xsv_test", 0755);
    int fd = open("/tmp/xsv_test/file.txt", O_WRONLY | O_CREAT | O_TRUNC, 0644);
    write(fd, "hello", 5); close(fd);

    errno = 0;
    fd = open("/tmp/xsv_test/file.txt/", O_RDONLY); // trailing slash
    printf("open(file/): fd=%d errno=%d\n", fd, errno);
    return (fd < 0) ? 0 : 1;
}