I didn't imagine that occasionally truncated pcap and log files, as a
result of commit d0006fa784a7 ("treewide: use _exit() over exit()"),
would be such a big deal, until I tried to debug TCP issues with this
beauty:

  while true; do ./pasta --trace -l /tmp/pasta.log -p /tmp/pasta.pcap --config-net -t 5555 -- socat TCP-LISTEN:5555 OPEN:/tmp/large.rcv,trunc & (sleep 0.3; socat -T2 OPEN:large.bin TCP:88.198.0.164:5555; ); wait; diff large.bin /tmp/large.rcv || break; done

...flush files and pcap if we're using them. Ignore fsync() errors for
the log file as we obviously can't reliably log them.

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>

This commit refines function comment headers for improved accuracy
and consistency. Key changes include:

- Corrected parameter/return descriptions (e.g., `logtime`, `__daemon`).
- Added missing and removed incorrect parameter documentation (e.g.,
  `tcp_vu_sock_recv`, `ndp`).
- Standardized comments to the `/** ... */` style for functions
  like `udp_flow_close` and `ns_enter`.
- Ensured function names in comments consistently use `()`.
- Addressed minor typos and updated comments for renamed functions.

Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>

This commit addresses several spelling errors identified by the `codespell`
tool. The corrections apply to:
- Code comments in `fwd.c`, `ip.h`, `isolation.c`, and `log.c`.
- An error message string in `vhost_user.c`.

Specifically, the following misspellings were corrected:
- "adddress" to "address"
- "capabilites" to "capabilities"
- "Musn't" to "Mustn't"
- "calculatd" to "calculated"
- "Invalide" to "Invalid"

Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>

We have some functions in our headers which are definitely there on
purpose.  However, they're not yet used outside the files in which they're
defined.  That causes sufficiently recent cppcheck versions (2.17) to
complain they should be static.

Suppress the errors for these "logically" exported functions.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>

passt_vsyslog() is an exposed function in log.h.  However it shouldn't
be called from outside log.c: it writes specifically to the system log,
and most code should call passt's logging helpers which might go to the
syslog or to a log file.

Make passt_vsyslog() local to log.c.  This requires a code motion to avoid
a forward declaration.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>

This marks static a number of functions which are only used in their .c
file, have no prototypes in a .h and were never intended to be globally
exposed.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>

With glibc commit 25a5eb4010df ("string: strerror, strsignal cannot
use buffer after dlmopen (bug 32026)"), strerror() now needs, at least
on x86, the getrandom() and brk() system calls, in order to fill in
the locale-translated error message. But getrandom() and brk() are not
allowed by our seccomp profiles.

This became visible on Fedora Rawhide with the "podman login and
logout" Podman tests, defined at test/e2e/login_logout_test.go in the
Podman source tree, where pasta would terminate upon printing error
descriptions (at least the ones related to the SO_ERROR queue for
spliced connections).

Avoid dynamic memory allocation by calling strerrordesc_np() instead,
which is a GNU function returning a static, untranslated version of
the error description. If it's not available, keep calling strerror(),
which at that point should be simple enough as to be usable (at least,
that's currently the case for musl).

Reported-by: Paul Holzinger <pholzing@redhat.com>
Link: https://github.com/containers/podman/issues/24804
Analysed-by: Paul Holzinger <pholzing@redhat.com>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Tested-by: Paul Holzinger <pholzing@redhat.com>

log.c has several #ifdefs on FALLOC_FL_COLLAPSE_RANGE that won't attempt
to use it if not defined.  But even if the value is defined at compile
time, it might not be available in the runtime kernel, so we need to check
for errors from a fallocate() call and fall back to other methods.

Simplify this to only need the runtime check by using linux_dep.h to define
FALLOC_FL_COLLAPSE_RANGE if it's not in the kernel headers.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>

In pcap_init(), we should always open the packet capture file with
O_CLOEXEC, even if we're not running in foreground: O_CLOEXEC means
close-on-exec, not close-on-fork.

In logfile_init() and pidfile_open(), the fact that we pass a third
'mode' argument to open() seems to confuse the android-cloexec-open
checker in LLVM versions from 16 to 19 (at least).

The checker is suggesting to add O_CLOEXEC to 'mode', and not in
'flags', where we already have it.

Add a suppression for clang-tidy and a comment, and avoid repeating
those three times by adding a new helper, output_file_open().

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>

We use fprintf() to print to standard output or standard error
streams. If something gets truncated or there's an output error, we
don't really want to try and report that, and at the same time it's
not abnormal behaviour upon which we should terminate, either.

Just silence the warning with an ugly FPRINTF() variadic macro casting
the fprintf() expressions to void.

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>