O_TRUNC setting.

[Userzxcvbvnm]

Test Case

The c test case is:

#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <unistd.h>

int get_fd(const char *filename, int flags) {
    int fd = open(filename, flags);

    if (fd == -1) {
        printf("Get file descriptor of file %s failed!\n", filename);
        return -1;
    } else {
        printf("Get file descriptor of file %s succeed!\n", filename);
        return fd;
    }
}

void closebyfd(int fd) {
    if (close(fd) == -1) {
        printf("Close the file %d by descriptor failed!\n", fd);
    }
}

void fd_fdstat_set_flags_00030_ZJtyU(int fd) {
    printf("Enter function fd_fdstat_set_flags_00030_ZJtyU\n");

    int flags = fcntl(fd, F_GETFL);
    flags = flags | O_TRUNC;

    if (fcntl(fd, F_SETFL, flags) == -1) {
        printf("Setting flags failed!\n");
    } else {
        printf("Setting flags succeed!\n");
    }
}

void print_flags(int fd){
    int flags1 = fcntl(fd, F_GETFL);
    int access_mode1 = flags1 & O_ACCMODE;
    if (access_mode1 == O_RDONLY) {
        printf("Access mode: Read Only\n");
    }
    if (access_mode1 == O_WRONLY) {
        printf("Access mode: Write Only\n");
    }
    if (access_mode1 == O_RDWR) {
        printf("Access mode: Read/Write\n");
    }
    if (flags1 & O_TRUNC) {
        printf("Access mode: O_TRUNC\n");
    }
    if (flags1 & O_APPEND) {
        printf("Access mode: O_APPEND\n");
    }
    if (flags1 & O_CREAT) {
        printf("Access mode: O_CREAT\n");
    }
    if (flags1 & O_EXCL) {
        printf("Access mode: O_EXCL\n");
    }
    if (flags1 & O_NONBLOCK) {
        printf("Access mode: Non-blocking\n");
    }
    if (flags1 & O_SYNC) {
        printf("Access mode: Synchronous Write\n");
    }
    if (flags1 & O_DSYNC) {
        printf("Access mode: Data Synchronization Write\n");
    }
}

int main() {

    int fd = get_fd("subdir_3/subdir_2/subfile_2", O_WRONLY | O_APPEND);

    if (fd == -1) {
        return 1;
    }

    print_flags(fd);
    fd_fdstat_set_flags_00030_ZJtyU(fd);
    printf("After setting flags\n");
    print_flags(fd);

    closebyfd(fd);

    return 0;
}

Steps to Reproduce

(1)compile to wasm:./wasi-sdk-21.0/bin/clang --target=wasm32-unkown-wasi --sysroot=./wasi-sdk-21.0/share/wasi-sysroot test.c -o test.wasm

(2)Running wasm: (Before run the Wasm file, file subdir_3/subdir_2/subfile_2 exists.) wasmtime run --dir=. test.wasm

Expected Results

Print:

Get file descriptor of file subdir_3/subdir_2/subfile_2 succeed!
Access mode: Read/Write
Access mode: O_APPEND
Enter function fd_fdstat_set_flags_00030_ZJtyU
Setting flags succeed!
After setting flags
Access mode: Read/Write
Access mode: O_APPEND

Actual Results

wasmtime prints:

Get file descriptor of file subdir_3/subdir_2/subfile_2 succeed!
Access mode: Read/Write
Access mode: O_APPEND
Enter function fd_fdstat_set_flags_00030_ZJtyU
Setting flags succeed!
After setting flags
Access mode: Read/Write
Access mode: O_TRUNC
Access mode: O_APPEND

Setting flags succeed, but do not print "Access mode: O_TRUNC". I'm not sure whether this is a bug.

Versions and Environment

Wasmtime version or commit: 19.0.2 and 13.0.1 Operating system: Ubuntu 20.04 Architecture: x86_64