Function execvpeZ_expandArg0 [src]

Like execvpeZ except if arg0_expand is .expand, then argv is mutable, and argv[0] is expanded to be the same absolute path that is passed to the execve syscall. If this function returns with an error, argv[0] will be restored to the value it was when it was passed in.

Prototype

 pub fn execvpeZ_expandArg0( comptime arg0_expand: Arg0Expand, file: [*:0]const u8, child_argv: switch (arg0_expand) { .expand => [*:null]?[*:0]const u8, .no_expand => [*:null]const ?[*:0]const u8, }, envp: [*:null]const ?[*:0]const u8, ) ExecveError

Parameters

arg0_expand: Arg0Expandfile: [*:0]const u8

child_argv: switch (arg0_expand) {
    .expand => [*:null]?[*:0]const u8,
    .no_expand => [*:null]const ?[*:0]const u8,
}

envp: [*:null]const ?[*:0]const u8

Source

  pub fn execvpeZ_expandArg0(
    comptime arg0_expand: Arg0Expand,
    file: [*:0]const u8,
    child_argv: switch (arg0_expand) {
        .expand => [*:null]?[*:0]const u8,
        .no_expand => [*:null]const ?[*:0]const u8,
    },
    envp: [*:null]const ?[*:0]const u8,
) ExecveError {
    const file_slice = mem.sliceTo(file, 0);
    if (mem.indexOfScalar(u8, file_slice, '/') != null) return execveZ(file, child_argv, envp);

    const PATH = getenvZ("PATH") orelse "/usr/local/bin:/bin/:/usr/bin";
    // Use of PATH_MAX here is valid as the path_buf will be passed
    // directly to the operating system in execveZ.
    var path_buf: [PATH_MAX]u8 = undefined;
    var it = mem.tokenizeScalar(u8, PATH, ':');
    var seen_eacces = false;
    var err: ExecveError = error.FileNotFound;

    // In case of expanding arg0 we must put it back if we return with an error.
    const prev_arg0 = child_argv[0];
    defer switch (arg0_expand) {
        .expand => child_argv[0] = prev_arg0,
        .no_expand => {},
    };

    while (it.next()) |search_path| {
        const path_len = search_path.len + file_slice.len + 1;
        if (path_buf.len < path_len + 1) return error.NameTooLong;
        @memcpy(path_buf[0..search_path.len], search_path);
        path_buf[search_path.len] = '/';
        @memcpy(path_buf[search_path.len + 1 ..][0..file_slice.len], file_slice);
        path_buf[path_len] = 0;
        const full_path = path_buf[0..path_len :0].ptr;
        switch (arg0_expand) {
            .expand => child_argv[0] = full_path,
            .no_expand => {},
        }
        err = execveZ(full_path, child_argv, envp);
        switch (err) {
            error.AccessDenied => seen_eacces = true,
            error.FileNotFound, error.NotDir => {},
            else => |e| return e,
        }
    }
    if (seen_eacces) return error.AccessDenied;
    return err;
}  