/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 1982, 1988, 1991 The Regents of the University of California.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#ifndef _SYS_SYSENT_H_
#define _SYS_SYSENT_H_

#include <bsm/audit.h>

struct rlimit;
struct sysent;
struct thread;
struct ksiginfo;
struct syscall_args;

enum systrace_probe_t {
        SYSTRACE_ENTRY,
        SYSTRACE_RETURN,
};

typedef int     sy_call_t(struct thread *, void *);

typedef void    (*systrace_probe_func_t)(struct syscall_args *,
                    enum systrace_probe_t, int);
typedef void    (*systrace_args_func_t)(int, void *, uint64_t *, int *);

#ifdef _KERNEL
extern systrace_probe_func_t    systrace_probe_func;
extern bool                     systrace_enabled;

#ifdef KDTRACE_HOOKS
#define SYSTRACE_ENABLED()      (systrace_enabled)
#else
#define SYSTRACE_ENABLED()      (0)
#endif
#endif /* _KERNEL */

struct sysent {                 /* system call table */
        sy_call_t *sy_call;     /* implementing function */
        systrace_args_func_t sy_systrace_args_func;
                                /* optional argument conversion function. */
        u_int8_t sy_narg;       /* number of arguments */
        u_int8_t sy_flags;      /* General flags for system calls. */
        au_event_t sy_auevent;  /* audit event associated with syscall */
        u_int32_t sy_entry;     /* DTrace entry ID for systrace. */
        u_int32_t sy_return;    /* DTrace return ID for systrace. */
        u_int32_t sy_thrcnt;
};

/*
 * A system call is permitted in capability mode.
 */
#define SYF_CAPENABLED  0x00000001

#define SY_THR_STATIC   0x01
#define SY_THR_DRAINING 0x02
#define SY_THR_ABSENT   0x04
#define SY_THR_INCR     0x08

#ifdef KLD_MODULE
#define SY_THR_STATIC_KLD       0
#else
#define SY_THR_STATIC_KLD       SY_THR_STATIC
#endif

struct coredump_writer;
struct image_params;
struct proc;
struct __sigset;
struct trapframe;
struct vnode;
struct note_info_list;

struct sysentvec {
        int             sv_size;        /* number of entries */
        struct sysent   *sv_table;      /* pointer to sysent */
        int             (*sv_fixup)(uintptr_t *, struct image_params *);
                                        /* stack fixup function */
        void            (*sv_sendsig)(void (*)(int), struct ksiginfo *, struct __sigset *);
                                        /* send signal */
        const char      *sv_sigcode;    /* start of sigtramp code */
        int             *sv_szsigcode;  /* size of sigtramp code */
        int             sv_sigcodeoff;
        char            *sv_name;       /* name of binary type */
        int             (*sv_coredump)(struct thread *, struct coredump_writer *,
                            off_t, int);
                                        /* function to dump core, or NULL */
        int             sv_elf_core_osabi;
        const char      *sv_elf_core_abi_vendor;
        void            (*sv_elf_core_prepare_notes)(struct thread *,
                            struct note_info_list *, size_t *);
        int             (*sv_copyout_auxargs)(struct image_params *,
                            uintptr_t);
        int             sv_minsigstksz; /* minimum signal stack size */
        vm_offset_t     sv_minuser;     /* VM_MIN_ADDRESS */
        vm_offset_t     sv_maxuser;     /* VM_MAXUSER_ADDRESS */
        vm_offset_t     sv_usrstack;    /* USRSTACK */
        vm_offset_t     sv_psstrings;   /* PS_STRINGS */
        size_t          sv_psstringssz; /* PS_STRINGS size */
        int             sv_stackprot;   /* vm protection for stack */
        int             (*sv_copyout_strings)(struct image_params *,
                            uintptr_t *);
        void            (*sv_setregs)(struct thread *, struct image_params *,
                            uintptr_t);
        void            (*sv_fixlimit)(struct rlimit *, int);
        u_long          *sv_maxssiz;
        u_int           sv_flags;
        void            (*sv_set_syscall_retval)(struct thread *, int);
        int             (*sv_fetch_syscall_args)(struct thread *);
        const char      **sv_syscallnames;
        vm_offset_t     sv_timekeep_offset;
        vm_offset_t     sv_shared_page_base;
        vm_offset_t     sv_shared_page_len;
        vm_offset_t     sv_sigcode_offset;
        void            *sv_shared_page_obj;
        vm_offset_t     sv_vdso_offset;
        void            (*sv_schedtail)(struct thread *);
        void            (*sv_thread_detach)(struct thread *);
        int             (*sv_trap)(struct thread *);
        u_long          *sv_hwcap;      /* Value passed in AT_HWCAP. */
        u_long          *sv_hwcap2;     /* Value passed in AT_HWCAP2. */
        u_long          *sv_hwcap3;     /* Value passed in AT_HWCAP3. */
        u_long          *sv_hwcap4;     /* Value passed in AT_HWCAP4. */
        const char      *(*sv_machine_arch)(struct proc *);
        vm_offset_t     sv_fxrng_gen_offset;
        void            (*sv_onexec_old)(struct thread *td);
        int             (*sv_onexec)(struct proc *, struct image_params *);
        void            (*sv_protect)(struct image_params *, int);
        void            (*sv_onexit)(struct proc *);
        void            (*sv_ontdexit)(struct thread *td);
        int             (*sv_setid_allowed)(struct thread *td,
                            struct image_params *imgp);
        void            (*sv_set_fork_retval)(struct thread *);
                                        /* Only used on x86 */
        struct regset   **sv_regset_begin;
        struct regset   **sv_regset_end;
};

#define SV_ILP32        0x000100        /* 32-bit executable. */
#define SV_LP64         0x000200        /* 64-bit executable. */
#define SV_RESERVED0    0x004000        /* Formerly SV_IA32 */
#define SV_AOUT         0x008000        /* a.out executable. */
#define SV_SHP          0x010000        /* Shared page. */
#define SV_SIGSYS       0x020000        /* SIGSYS for non-existing syscall */
#define SV_TIMEKEEP     0x040000        /* Shared page timehands. */
#define SV_ASLR         0x080000        /* ASLR allowed. */
#define SV_RNG_SEED_VER 0x100000        /* random(4) reseed generation. */
#define SV_SIG_DISCIGN  0x200000        /* Do not discard ignored signals */
#define SV_SIG_WAITNDQ  0x400000        /* Wait does not dequeue SIGCHLD */
#define SV_DSO_SIG      0x800000        /* Signal trampoline packed in dso */

#define SV_ABI_MASK     0xff
#define SV_PROC_FLAG(p, x)      ((p)->p_sysent->sv_flags & (x))
#define SV_PROC_ABI(p)          ((p)->p_sysent->sv_flags & SV_ABI_MASK)
#define SV_CURPROC_FLAG(x)      SV_PROC_FLAG(curproc, x)
#define SV_CURPROC_ABI()        SV_PROC_ABI(curproc)
/* same as ELFOSABI_XXX, to prevent header pollution */
#define SV_ABI_LINUX    3
#define SV_ABI_FREEBSD  9
#define SV_ABI_UNDEF    255

/* sv_coredump flags */
#define SVC_PT_COREDUMP 0x00000001      /* dump requested by ptrace(2) */
#define SVC_NOCOMPRESS  0x00000002      /* disable compression. */
#define SVC_ALL         0x00000004      /* dump everything */

/* sv_protect flags */
#define SVP_IMAGE       0x00000001
#define SVP_INTERP      0x00000002

#ifdef _KERNEL
extern struct sysentvec aout_sysvec;
extern struct sysent sysent[];
extern const char *syscallnames[];
extern struct sysent nosys_sysent;

struct nosys_args {
        register_t dummy;
};

int     nosys(struct thread *, struct nosys_args *);

#define NO_SYSCALL (-1)

struct module;

struct syscall_module_data {
        int     (*chainevh)(struct module *, int, void *); /* next handler */
        void    *chainarg;              /* arg for next event handler */
        int     *offset;                /* offset into sysent */
        struct sysent *new_sysent;      /* new sysent */
        struct sysent old_sysent;       /* old sysent */
        int     flags;                  /* flags for syscall_register */
};

/* separate initialization vector so it can be used in a substructure */
#define SYSENT_INIT_VALS(_syscallname) {                        \
        .sy_narg = (sizeof(struct _syscallname ## _args )       \
            / sizeof(register_t)),                              \
        .sy_call = (sy_call_t *)&sys_##_syscallname,            \
        .sy_auevent = SYS_AUE_##_syscallname,                   \
        .sy_systrace_args_func = NULL,                          \
        .sy_entry = 0,                                          \
        .sy_return = 0,                                         \
        .sy_flags = 0,                                          \
        .sy_thrcnt = 0                                          \
}

#define MAKE_SYSENT(syscallname)                                \
static struct sysent syscallname##_sysent = SYSENT_INIT_VALS(syscallname);

#define MAKE_SYSENT_COMPAT(syscallname)                         \
static struct sysent syscallname##_sysent = {                   \
        (sizeof(struct syscallname ## _args )                   \
            / sizeof(register_t)),                              \
        (sy_call_t *)& syscallname,                             \
        SYS_AUE_##syscallname                                   \
}

#define SYSCALL_MODULE(name, offset, new_sysent, evh, arg)      \
static struct syscall_module_data name##_syscall_mod = {        \
        evh, arg, offset, new_sysent, { 0, NULL, AUE_NULL }     \
};                                                              \
                                                                \
static moduledata_t name##_mod = {                              \
        "sys/" #name,                                           \
        syscall_module_handler,                                 \
        &name##_syscall_mod                                     \
};                                                              \
DECLARE_MODULE(name, name##_mod, SI_SUB_SYSCALLS, SI_ORDER_MIDDLE)

#define SYSCALL_MODULE_HELPER(syscallname)                      \
static int syscallname##_syscall = SYS_##syscallname;           \
MAKE_SYSENT(syscallname);                                       \
SYSCALL_MODULE(syscallname,                                     \
    & syscallname##_syscall, & syscallname##_sysent,            \
    NULL, NULL)

#define SYSCALL_MODULE_PRESENT(syscallname)                             \
        (sysent[SYS_##syscallname].sy_call != (sy_call_t *)lkmnosys &&  \
        sysent[SYS_##syscallname].sy_call != (sy_call_t *)lkmressys)

/*
 * Syscall registration helpers with resource allocation handling.
 */
struct syscall_helper_data {
        struct sysent new_sysent;
        struct sysent old_sysent;
        int syscall_no;
        int registered;
};
#define SYSCALL_INIT_HELPER_F(syscallname, flags) {             \
    .new_sysent = {                                             \
        .sy_narg = (sizeof(struct syscallname ## _args )        \
            / sizeof(register_t)),                              \
        .sy_call = (sy_call_t *)& sys_ ## syscallname,          \
        .sy_auevent = SYS_AUE_##syscallname,                    \
        .sy_flags = (flags)                                     \
    },                                                          \
    .syscall_no = SYS_##syscallname                             \
}
#define SYSCALL_INIT_HELPER_COMPAT_F(syscallname, flags) {      \
    .new_sysent = {                                             \
        .sy_narg = (sizeof(struct syscallname ## _args )        \
            / sizeof(register_t)),                              \
        .sy_call = (sy_call_t *)& syscallname,                  \
        .sy_auevent = SYS_AUE_##syscallname,                    \
        .sy_flags = (flags)                                     \
    },                                                          \
    .syscall_no = SYS_##syscallname                             \
}
#define SYSCALL_INIT_HELPER(syscallname)                        \
    SYSCALL_INIT_HELPER_F(syscallname, 0)
#define SYSCALL_INIT_HELPER_COMPAT(syscallname)                 \
    SYSCALL_INIT_HELPER_COMPAT_F(syscallname, 0)
#define SYSCALL_INIT_LAST {                                     \
    .syscall_no = NO_SYSCALL                                    \
}

int     syscall_module_handler(struct module *mod, int what, void *arg);
int     syscall_helper_register(struct syscall_helper_data *sd, int flags);
int     syscall_helper_unregister(struct syscall_helper_data *sd);
/* Implementation, exposed for COMPAT code */
int     kern_syscall_register(struct sysent *sysents, int *offset,
            struct sysent *new_sysent, struct sysent *old_sysent, int flags);
int     kern_syscall_deregister(struct sysent *sysents, int offset,
            const struct sysent *old_sysent);
int     kern_syscall_module_handler(struct sysent *sysents,
            struct module *mod, int what, void *arg);
int     kern_syscall_helper_register(struct sysent *sysents,
            struct syscall_helper_data *sd, int flags);
int     kern_syscall_helper_unregister(struct sysent *sysents,
            struct syscall_helper_data *sd);

struct proc;
const char *syscallname(struct proc *p, u_int code);

/* Special purpose system call functions. */
struct nosys_args;

int     lkmnosys(struct thread *, struct nosys_args *);
int     lkmressys(struct thread *, struct nosys_args *);

int     syscall_thread_enter(struct thread *td, struct sysent **se);
void    syscall_thread_exit(struct thread *td, struct sysent *se);

int shared_page_alloc(int size, int align);
int shared_page_fill(int size, int align, const void *data);
void shared_page_write(int base, int size, const void *data);
void exec_sysvec_init(void *param);
void exec_sysvec_init_secondary(struct sysentvec *sv, struct sysentvec *sv2);
void exec_inittk(void);

void exit_onexit(struct proc *p);
void exec_free_abi_mappings(struct proc *p);
void exec_onexec_old(struct thread *td);

#define INIT_SYSENTVEC(name, sv)                                        \
    SYSINIT(name, SI_SUB_EXEC, SI_ORDER_ANY, exec_sysvec_init, sv)

#endif /* _KERNEL */

#endif /* !_SYS_SYSENT_H_ */