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'.
guestfs_fallocate takes an integer for the length, effectively
limiting it to creating 1GB files. This new call takes an int64_t
for the length, but is otherwise identical.
posix_fallocate has a non-standard way to return error indications.
Thus all our calls to posix_fallocate were effectively unchecked. For
example:
$ guestfish alloc test.img 1P
$ echo $?
0
$ ll test.img
-rw-rw-r--. 1 rjones rjones 0 2010-04-06 11:02 test.img
$ rm test.img
With this change, errors are detected and reported properly:
$ ./fish/guestfish alloc test.img 1P
fallocate: File too large
This is a fix for:
https://bugzilla.redhat.com/show_bug.cgi?id=579664
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.
