#!/bin/bash
# Compatibility shims for systemd 259.1 against the Pagan native rootfs headers.
set -euo pipefail

# systemd ships missing kernel UAPI bits under src/include/override and
# src/include/uapi. Meson adds those as -isystem, but pkg-config injects
# -I$PAGAN_ROOT/usr/include which wins and hides the overrides. Flip them
# to regular -I so MQUEUE_MAGIC, EXT4_IOC_RESIZE_FS, key_serial_t, etc. work.
if [[ -f meson.build ]]; then
    python3 - <<'PY'
from pathlib import Path
p = Path("meson.build")
t = p.read_text()
t = t.replace("is_system : true", "is_system : false")
for kind in ("override", "uapi"):
    t = t.replace(
        f"'-isystem', meson.project_build_root()  / 'src/include/{kind}'",
        f"'-I', meson.project_build_root()  / 'src/include/{kind}'",
    )
    t = t.replace(
        f"'-isystem', meson.project_source_root() / 'src/include/{kind}'",
        f"'-I', meson.project_source_root() / 'src/include/{kind}'",
    )
# Inject missing MAGIC macros via -imacros after config.h.
marker = "userspace_c_args += ['-include', 'config.h']"
inject = (
    marker
    + "\nuserspace_c_args += ['-imacros', meson.project_source_root() / 'src/include/override/pagan-compat.h']"
)
if marker in t and "pagan-compat.h" not in t:
    t = t.replace(marker, inject, 1)
p.write_text(t)
print("patched meson.build: systemd override headers now use -I")
PY
fi

# keyctl.c provides missing_keyctl/missing_add_key/missing_request_key syscall
# wrappers (required at link time).  We removed the keyutils.h injection that
# caused the old header conflict, so the file is safe to keep.
if [[ -f src/libc/meson.build ]] && ! grep -q "'keyctl.c'" src/libc/meson.build; then
    sed -i "/'xattr.c',/a\        'keyctl.c'," src/libc/meson.build
fi

# linux/keyctl.h on the target does not declare key_serial_t.
if [[ -f src/include/override/sys/keyctl.h ]]; then
    if ! grep -q 'KEY_SERIAL_T_DEFINED' src/include/override/sys/keyctl.h; then
        sed -i '1i #include <stdint.h>\n#ifndef KEY_SERIAL_T_DEFINED\n#define KEY_SERIAL_T_DEFINED\ntypedef int32_t key_serial_t;\n#endif' \
            src/include/override/sys/keyctl.h
    fi
fi

# Include libc networking headers before Linux netfilter headers.
if [[ -f src/shared/firewall-util.c ]]; then
    sed -i \
        -e '/^#include <linux\/netfilter\/nf_tables.h>/d' \
        -e '/^#include <linux\/netfilter_ipv4.h>/d' \
        -e '/^#include <netinet\/ip.h>/d' \
        -e '/^#include <netinet\/ip6.h>/d' \
        -e '/^#include <endian.h>$/a #include <netinet/ip.h>\n#include <netinet/ip6.h>\n#include <linux/netfilter/nf_tables.h>\n#include <linux/netfilter_ipv4.h>' \
        src/shared/firewall-util.c
fi

# TASK_COMM_LEN is not exported by the target kernel headers.
if [[ -f src/shared/nsresource.c ]] && ! grep -q 'TASK_COMM_LEN 16' src/shared/nsresource.c; then
    sed -i '1i #ifndef TASK_COMM_LEN\n#define TASK_COMM_LEN 16\n#endif' src/shared/nsresource.c
fi

# EXT4_IOC_RESIZE_FS lives in linux/ext4.h, not linux/fs.h.
if [[ -f src/shared/resize-fs.c ]] && ! grep -q 'linux/ext4.h' src/shared/resize-fs.c; then
    sed -i '/#include <linux\/fs.h>/a #include <linux/ext4.h>' src/shared/resize-fs.c
fi

# The target sysroot linux/keyctl.h lacks the KEY_POS/KEY_USR/KEY_GRP/KEY_OTH
# keyring permission masks.  systemd's override/linux/keyctl.h has them but is
# shadowed by uapi/linux/keyctl.h (uapi comes first in -I order).  Inject the
# block into the uapi header that keyring code actually includes.  Safe: the
# udev keyboard generator only includes <linux/input.h>, so it never sees them.
if [[ -f src/include/uapi/linux/keyctl.h ]] && ! grep -q 'define KEY_POS_VIEW' src/include/uapi/linux/keyctl.h; then
    python3 - <<'PY'
from pathlib import Path
p = Path("src/include/uapi/linux/keyctl.h")
t = p.read_text()
block = '''
#ifndef KEY_POS_VIEW
#define KEY_POS_VIEW    0x01000000
#define KEY_POS_READ    0x02000000
#define KEY_POS_WRITE   0x04000000
#define KEY_POS_SEARCH  0x08000000
#define KEY_POS_LINK    0x10000000
#define KEY_POS_SETATTR 0x20000000
#define KEY_POS_ALL     0x3f000000
#define KEY_USR_VIEW    0x00010000
#define KEY_USR_READ    0x00020000
#define KEY_USR_WRITE   0x00040000
#define KEY_USR_SEARCH  0x00080000
#define KEY_USR_LINK    0x00100000
#define KEY_USR_SETATTR 0x00200000
#define KEY_USR_ALL     0x003f0000
#define KEY_GRP_VIEW    0x00000100
#define KEY_GRP_READ    0x00000200
#define KEY_GRP_WRITE   0x00000400
#define KEY_GRP_SEARCH  0x00000800
#define KEY_GRP_LINK    0x00001000
#define KEY_GRP_SETATTR 0x00002000
#define KEY_GRP_ALL     0x00003f00
#define KEY_OTH_VIEW    0x00000001
#define KEY_OTH_READ    0x00000002
#define KEY_OTH_WRITE   0x00000004
#define KEY_OTH_SEARCH  0x00000008
#define KEY_OTH_LINK    0x00000010
#define KEY_OTH_SETATTR 0x00000020
#define KEY_OTH_ALL     0x0000003f
#endif
'''
import re as _re
m = _re.search(r'#endif\s*/\*.*?_LINUX_KEYCTL_H.*?\*/', t, _re.S)
if m:
    t = t[:m.start()] + block + '\n' + m.group(0)
else:
    idx = t.rstrip().rfind('\n#endif')
    t = t.rstrip()[:idx] + block + '\n#endif\n'
p.write_text(t)
print("patched uapi/linux/keyctl.h with keyring permission masks")
PY
fi

# Force-include remaining kernel constants that systemd's override headers
# also provide, in case some translation unit still misses them.
compat_h="src/include/override/pagan-compat.h"
cat > "$compat_h" <<'EOF'
/* SPDX-License-Identifier: LGPL-2.1-or-later */
/* Macros only.  Safe with -imacros: no includes, no typedefs. */
#ifndef _GNU_SOURCE
#define _GNU_SOURCE 1
#endif
#ifndef TASK_COMM_LEN
#define TASK_COMM_LEN 16
#endif
#ifndef MQUEUE_MAGIC
#define MQUEUE_MAGIC 0x19800202
#endif
#ifndef BALLOON_KVM_MAGIC
#define BALLOON_KVM_MAGIC 0x13661366
#endif
#ifndef ZSMALLOC_MAGIC
#define ZSMALLOC_MAGIC 0x58295829
#endif
#ifndef Z3FOLD_MAGIC
#define Z3FOLD_MAGIC 0x33
#endif
#ifndef PPC_CMM_MAGIC
#define PPC_CMM_MAGIC 0xc7571590
#endif
#ifndef SHIFTFS_MAGIC
#define SHIFTFS_MAGIC 0x6a656a62
#endif
#ifndef FUSE_CTL_SUPER_MAGIC
#define FUSE_CTL_SUPER_MAGIC 0x65735543
#endif
#ifndef ORANGEFS_DEVREQ_MAGIC
#define ORANGEFS_DEVREQ_MAGIC 0x20030529
#endif
#ifndef GFS2_MAGIC
#define GFS2_MAGIC 0x01161970
#endif
#ifndef CONFIGFS_MAGIC
#define CONFIGFS_MAGIC 0x62656570
#endif
#ifndef VBOXSF_SUPER_MAGIC
#define VBOXSF_SUPER_MAGIC 0x786f4256
#endif
#ifndef RPC_PIPEFS_SUPER_MAGIC
#define RPC_PIPEFS_SUPER_MAGIC 0x67596969
#endif
#ifndef NTFS_SB_MAGIC
#define NTFS_SB_MAGIC 0x5346544e
#endif
#ifndef NTFS3_SUPER_MAGIC
#define NTFS3_SUPER_MAGIC 0x7366746e
#endif
#ifndef EXT4_IOC_RESIZE_FS
#define EXT4_IOC_RESIZE_FS _IOW('f', 16, unsigned long long)
#endif
#ifndef FILEID_KERNFS
#define FILEID_KERNFS 0xfe
#endif
/* NOTE: do NOT force-define the KEY_POS / KEY_USR keyring permission
 * masks here.  They are provided by systemd's override linux/keyctl.h
 * (which now wins because overrides use -I).  Injecting them globally
 * would pollute the udev keyboard key list (compiled through our
 * -imacros) and overflow its unsigned-short key code field. */
/* Unconditional BPF jump (from linux/filter.h).  Function-like macro, so it
 * only expands at call sites where struct bpf_insn / BPF_JMP / BPF_JA are
 * already declared. */
#ifndef BPF_JMP_A
#define BPF_JMP_A(OFF) \
        ((struct bpf_insn) { .code = BPF_JMP | BPF_JA, .dst_reg = 0, .src_reg = 0, .off = (OFF), .imm = 0 })
#endif
#ifndef O_LARGEFILE
#define O_LARGEFILE 0
#endif
#ifndef O_NOATIME
#define O_NOATIME 01000000
#endif
#ifndef MFD_ALLOW_SEALING
#define MFD_ALLOW_SEALING 2U
#endif
EOF

# -imacros injects the macros without changing include search order
# and without parsing the file as a translation-unit include.
export CFLAGS="${CFLAGS:-} -D_GNU_SOURCE -imacros ${PWD}/${compat_h}"
export CXXFLAGS="${CXXFLAGS:-} -D_GNU_SOURCE -imacros ${PWD}/${compat_h}"