3f13989883
Gate 1, item 3, and the last of foundations.md.
bind() creates a T_SOCK node at the path; connect() resolves the path and looks
for the socket bound to **that inode**. Matching on the inode rather than on
the path *string* is the part that matters: the name used to live only in the
socket table, so two spellings of one path missed each other, a relative path
never matched an absolute one, and there was nothing to stat() or unlink().
An inode is the thing a path resolves *to*, so connect() can walk the path
however it likes and arrive at the same socket.
# ls -l /tmp
srwxr-xr-x 1 root root 0 2026-09-22 08:04 socktest
The node is a marker, not the binding. It holds no data and the live
association stays in the socket table, so a socket file left by a crash is
what Linux leaves behind -- a dead file that connect() refuses until something
binds again -- and unlink()ing a live socket's path does not disturb anyone
already connected.
EADDRINUSE comes from the *directory* rather than from a scan of the table,
deliberately: a stale socket file has to refuse a rebind for the same reason a
running server's does, or two servers both believe they own it. The creation
lives in sys_bind() and not in unix.c, because that is the layer with both --
kernel/net/unix.c knows about sockets and has no business calling create().
T_SOCK is a compat addition to SchFS by the rule in schfs.h: a driver that does
not know SCHFS_T_SOCK maps it to a zero-length regular file, so nothing goes
stale and nothing becomes unreadable.
cmd/socktest section 15 asserts the plan's own wording -- bind, stat, see an
`s`, unlink -- plus the two a name table could never fail: a second bind to a
live path is refused, and connecting to a path that is a *regular file* is
refused rather than matched by name.
**And the semantics being real broke socktest on its second run**, correctly:
the socket files persisted and every bind() hit EADDRINUSE. Every real server
unlinks before binding; socktest now does too, which is the change the new
behaviour demands rather than a workaround for it.
Chasing that turned up something worse. `socktest` reported rc=1 with every
check passing, and so did every other first-party program:
- **lib/start.S called main and threw %eax away.** sys_exit() reads the
status from %rdi and nothing put it there, so every program exited with
whatever that register happened to hold. Every test suite ends in
`return failures ? 1 : 0` and none of it reached the shell.
- **exit(void) passed no status either**, for the same reason: the
declaration takes no argument, so %rdi was the caller's litter.
`if socktest; then` works now, and a failing command reports 1 -- checked both
ways, because a fix that makes everything return 0 would look identical from
the success side.
Also factored: unlink_path() out of sys_unlink, so a failed bind can take its
own node back out without going through the syscall entry, and create_sock()
as a named door rather than exporting create() with an arbitrary type.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
31 lines
1.2 KiB
C
31 lines
1.2 KiB
C
#pragma once
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#include "types.h"
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#define T_DIR 1 // Directory
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#define T_FILE 2 // File
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#define T_DEV 3 // Device
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#define T_SYMLINK 4 // Divesymlink
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#define T_EXTENT 5 // bmap & itrunc
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// A bound AF_UNIX socket. The node is a *marker*: it is what makes a socket
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// findable by path, stat()able and unlink()able, and it holds no data. The
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// live binding lives in kernel/net/unix.c and is matched by (dev, inum), not
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// by this node's contents -- so a socket file left behind by a crash is
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// exactly what Linux leaves behind, a dead file that connect() refuses until
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// something binds to it again.
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#define T_SOCK 6
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struct stat {
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int32 type; // File type (T_DIR, T_FILE, or T_DEV)
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int32 dev; // File system's disk device ID
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uint64 ino; // Inode number
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int32 nlink; // Number of hard links to file
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uint32 pad; // Padding for 64-bit alignment
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uint64 size; // Size of file in bytes
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uint rwmode; // Permissions
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uint supermode; // Mode
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uint showmode; // Visiblity
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uint atime; // Last access time
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uint mtime; // Last modification time
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uint ctime; // Last metadata-change time
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uint addrs[12+3]; // Block Addresses
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};
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