The presumption is that all file descriptors should be created with
the close-on-exec flag set. The only exception are file descriptors
that we want passed through to exec'd subprocesses (mainly pipes and
stdin/stdout/stderr).
For open calls, we pass O_CLOEXEC as an extra flag, eg:
fd = open ("foo", O_RDONLY|O_CLOEXEC);
This is a Linux-ism, but using a macro we can easily make it portable.
For sockets, similarly:
sock = socket (..., SOCK_STREAM|SOCK_CLOEXEC, ...);
For accepted sockets, we use the Linux accept4 system call which
allows flags to be supplied, but we use the Gnulib 'accept4' module to
make this portable.
For dup, dup2, we use the Linux dup3 system call, and the Gnulib
modules 'dup3' and 'cloexec'.
The RPC stubs already prefix the command name to error messages.
The daemon doesn't have to do this. As a (small) benefit this also
makes the daemon slightly smaller.
Code in the daemon such as:
if (argv[0] == NULL) {
reply_with_error ("passed an empty list");
return NULL;
}
now results in error messages like this:
><fs> command ""
libguestfs: error: command: passed an empty list
(whereas previously you would have seen ..command: command:..)
Nearly every file-related function in daemons/*.c is affected:
Remove this pair of statements from each affected do_* function:
- NEED_ROOT (return -1);
- ABS_PATH (dir, return -1);
and change the type of the corresponding parameter to "const char *".
* src/generator.ml: Emit NEED_ROOT just once, even when there are two or
more Pathname args.
Currently /sysroot is hard-coded throughout the daemon code.
This patch turns the path into a variable so that we can change
it in future, for example to allow standalone mode to be implemented.
This patch was tested by running all the C API tests successfully.
