While here also fix a fd leak in got-read-pack. We were dup'ing imsg.fd without closing imsg.fd later; instead just use imsg_get_fd() to extract the file descriptor. Tested by falsifian and Kyle Ackerman, thanks! 'go ahead' stsp@

Move some functions from object_parse.c into hash.c. These functions either require hash.c code anyway or contain object ID implementation internals. Add a new file object_qid.c, for got_object_id_queue and got_object_qid. This new file must be linked to virtually every program.

Rather than assume all dependencies are required for all programs, split them out. This will make packaging easier, as well as splitting the code to use subprojects. Note that due to the use of config.h semantics, in most cases the got_compat.h header file is now at the top of the .c file it is included in, so that it can handle the system header inclusion properly.

This adds a set of functions to abstract over SHA1Init, SHA1Update, SHA1Final, their respective SHA256 variants and how to compare digests. Replace all the SHA1*() usage with the new APIs. It's a preparatory step for sha256 handling. ok stsp@

Simply the SHA detection by not predicating on libcrypto, but instead checking individual header files.

Remove sha1.h as this is found portably across systems.

In preparation for wide sha256 support; stsp@ agrees. Change done mechanically with find . -iname \*.[cy] -exec sam {} + X ,x/<sha1\.h>/i/\n#include <sha2.h>

It's only a preparatory step, as checking whether a size_t is less than SIZE_MAX is moot. In a follow-up commit, however, the `filesize' field of the struct got_pack will become off_t and these checks will kick in. This also makes consistent how we guard mmap(2) against empty files. ok and improvements stsp@

Prepares for sharing code between got-index-pack and future gotd(8).

"looks good to me" millert@

Now that the handling of including sys/queue.h is better, there's no need to remove those lines from the source. Copy the location of those original sys/queue.h lines from upstream at the same line number, so as to avoid any conflicts in the future.

Thanks to the design of Got, the libexec helpers don't need any resource (in fact they run under pledge "stdio recvfd" on OpenBSD) and so using cap_enter(2) on FreeBSD is dead-easy. While the main process can't be sandboxed on FreeBSD (needs to exec the helpers), all the tough work is done by these small libexec helpers which is also the biggest attack surface. tested by naddy, ok thomas

This approach uses more memory but is much faster. To offset the additional memory usage somewhat the cache now stores very small deltas only. However, overall memory usage goes up. Hopefully we will find a way to reduce this later. ok op@

landlock is a new set of linux APIs that is conceptually similar to unveil(2): the idea is to restrict what a process can do on a specified part of the filesystem. There are some differences in the behaviour: the major one being that the landlock ruleset is inherited across execve(2). This just restricts the libexec helpers by completely revoking ANY filesystem access; after all they are the biggest attack surface. got send/fetch/clone *may* end up spawning ssh(1), so at the moment is not possible to landlock the main process. From Omar Polo.

This adds the capability to compile got-portable on FreeBSD.

This commit modifies the GoT main branch to be able to compile it under linux.