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qemu/bsd-user/syscall.c
Alex Bennée f7e68c9c99 tcg/plugins: implement a qemu_plugin_user_exit helper 
In user-mode emulation there is a small race between preexit_cleanup
and exit_group() which means we may end up calling instrumented
instructions before the kernel reaps child threads. To solve this we
implement a new helper which ensures the callbacks are flushed along
with any translations before we let the host do it's a thing.

While we are at it make the documentation of
qemu_plugin_register_atexit_cb clearer as to what the user can expect.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Mahmoud Mandour <ma.mandourr@gmail.com>
Acked-by: Warner Losh <imp@bsdimp.com>
Message-Id: <20210720232703.10650-21-alex.bennee@linaro.org>
2021-07-23 17:22:16 +01:00

578 lines
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/*
* BSD syscalls
*
* Copyright (c) 2003 - 2008 Fabrice Bellard
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see <http://www.gnu.org/licenses/>.
*/
#include "qemu/osdep.h"
#include "qemu/cutils.h"
#include "qemu/path.h"
#include <sys/syscall.h>
#include <sys/param.h>
#include <sys/sysctl.h>
#include <utime.h>
#include "qemu.h"
#include "qemu-common.h"
#include "user/syscall-trace.h"
//#define DEBUG
static abi_ulong target_brk;
static abi_ulong target_original_brk;
static inline abi_long get_errno(abi_long ret)
{
if (ret == -1)
/* XXX need to translate host -> target errnos here */
return -(errno);
else
return ret;
}
#define target_to_host_bitmask(x, tbl) (x)
static inline int is_error(abi_long ret)
{
return (abi_ulong)ret >= (abi_ulong)(-4096);
}
void target_set_brk(abi_ulong new_brk)
{
target_original_brk = target_brk = HOST_PAGE_ALIGN(new_brk);
}
/* do_obreak() must return target errnos. */
static abi_long do_obreak(abi_ulong new_brk)
{
abi_ulong brk_page;
abi_long mapped_addr;
int new_alloc_size;
if (!new_brk)
return 0;
if (new_brk < target_original_brk)
return -TARGET_EINVAL;
brk_page = HOST_PAGE_ALIGN(target_brk);
/* If the new brk is less than this, set it and we're done... */
if (new_brk < brk_page) {
target_brk = new_brk;
return 0;
}
/* We need to allocate more memory after the brk... */
new_alloc_size = HOST_PAGE_ALIGN(new_brk - brk_page + 1);
mapped_addr = get_errno(target_mmap(brk_page, new_alloc_size,
PROT_READ|PROT_WRITE,
MAP_ANON|MAP_FIXED|MAP_PRIVATE, -1, 0));
if (!is_error(mapped_addr))
target_brk = new_brk;
else
return mapped_addr;
return 0;
}
#if defined(TARGET_I386)
static abi_long do_freebsd_sysarch(CPUX86State *env, int op, abi_ulong parms)
{
abi_long ret = 0;
abi_ulong val;
int idx;
switch (op) {
#ifdef TARGET_ABI32
case TARGET_FREEBSD_I386_SET_GSBASE:
case TARGET_FREEBSD_I386_SET_FSBASE:
if (op == TARGET_FREEBSD_I386_SET_GSBASE)
#else
case TARGET_FREEBSD_AMD64_SET_GSBASE:
case TARGET_FREEBSD_AMD64_SET_FSBASE:
if (op == TARGET_FREEBSD_AMD64_SET_GSBASE)
#endif
idx = R_GS;
else
idx = R_FS;
if (get_user(val, parms, abi_ulong))
return -TARGET_EFAULT;
cpu_x86_load_seg(env, idx, 0);
env->segs[idx].base = val;
break;
#ifdef TARGET_ABI32
case TARGET_FREEBSD_I386_GET_GSBASE:
case TARGET_FREEBSD_I386_GET_FSBASE:
if (op == TARGET_FREEBSD_I386_GET_GSBASE)
#else
case TARGET_FREEBSD_AMD64_GET_GSBASE:
case TARGET_FREEBSD_AMD64_GET_FSBASE:
if (op == TARGET_FREEBSD_AMD64_GET_GSBASE)
#endif
idx = R_GS;
else
idx = R_FS;
val = env->segs[idx].base;
if (put_user(val, parms, abi_ulong))
return -TARGET_EFAULT;
break;
/* XXX handle the others... */
default:
ret = -TARGET_EINVAL;
break;
}
return ret;
}
#endif
#ifdef TARGET_SPARC
static abi_long do_freebsd_sysarch(void *env, int op, abi_ulong parms)
{
/* XXX handle
* TARGET_FREEBSD_SPARC_UTRAP_INSTALL,
* TARGET_FREEBSD_SPARC_SIGTRAMP_INSTALL
*/
return -TARGET_EINVAL;
}
#endif
#ifdef __FreeBSD__
/*
* XXX this uses the undocumented oidfmt interface to find the kind of
* a requested sysctl, see /sys/kern/kern_sysctl.c:sysctl_sysctl_oidfmt()
* (this is mostly copied from src/sbin/sysctl/sysctl.c)
*/
static int
oidfmt(int *oid, int len, char *fmt, uint32_t *kind)
{
int qoid[CTL_MAXNAME+2];
uint8_t buf[BUFSIZ];
int i;
size_t j;
qoid[0] = 0;
qoid[1] = 4;
memcpy(qoid + 2, oid, len * sizeof(int));
j = sizeof(buf);
i = sysctl(qoid, len + 2, buf, &j, 0, 0);
if (i)
return i;
if (kind)
*kind = *(uint32_t *)buf;
if (fmt)
strcpy(fmt, (char *)(buf + sizeof(uint32_t)));
return (0);
}
/*
* try and convert sysctl return data for the target.
* XXX doesn't handle CTLTYPE_OPAQUE and CTLTYPE_STRUCT.
*/
static int sysctl_oldcvt(void *holdp, size_t holdlen, uint32_t kind)
{
switch (kind & CTLTYPE) {
case CTLTYPE_INT:
case CTLTYPE_UINT:
*(uint32_t *)holdp = tswap32(*(uint32_t *)holdp);
break;
#ifdef TARGET_ABI32
case CTLTYPE_LONG:
case CTLTYPE_ULONG:
*(uint32_t *)holdp = tswap32(*(long *)holdp);
break;
#else
case CTLTYPE_LONG:
*(uint64_t *)holdp = tswap64(*(long *)holdp);
break;
case CTLTYPE_ULONG:
*(uint64_t *)holdp = tswap64(*(unsigned long *)holdp);
break;
#endif
#ifdef CTLTYPE_U64
case CTLTYPE_S64:
case CTLTYPE_U64:
#else
case CTLTYPE_QUAD:
#endif
*(uint64_t *)holdp = tswap64(*(uint64_t *)holdp);
break;
case CTLTYPE_STRING:
break;
default:
/* XXX unhandled */
return -1;
}
return 0;
}
/* XXX this needs to be emulated on non-FreeBSD hosts... */
static abi_long do_freebsd_sysctl(abi_ulong namep, int32_t namelen, abi_ulong oldp,
abi_ulong oldlenp, abi_ulong newp, abi_ulong newlen)
{
abi_long ret;
void *hnamep, *holdp, *hnewp = NULL;
size_t holdlen;
abi_ulong oldlen = 0;
int32_t *snamep = g_malloc(sizeof(int32_t) * namelen), *p, *q, i;
uint32_t kind = 0;
if (oldlenp)
get_user_ual(oldlen, oldlenp);
if (!(hnamep = lock_user(VERIFY_READ, namep, namelen, 1)))
return -TARGET_EFAULT;
if (newp && !(hnewp = lock_user(VERIFY_READ, newp, newlen, 1)))
return -TARGET_EFAULT;
if (!(holdp = lock_user(VERIFY_WRITE, oldp, oldlen, 0)))
return -TARGET_EFAULT;
holdlen = oldlen;
for (p = hnamep, q = snamep, i = 0; i < namelen; p++, i++)
*q++ = tswap32(*p);
oidfmt(snamep, namelen, NULL, &kind);
/* XXX swap hnewp */
ret = get_errno(sysctl(snamep, namelen, holdp, &holdlen, hnewp, newlen));
if (!ret)
sysctl_oldcvt(holdp, holdlen, kind);
put_user_ual(holdlen, oldlenp);
unlock_user(hnamep, namep, 0);
unlock_user(holdp, oldp, holdlen);
if (hnewp)
unlock_user(hnewp, newp, 0);
g_free(snamep);
return ret;
}
#endif
/* FIXME
* lock_iovec()/unlock_iovec() have a return code of 0 for success where
* other lock functions have a return code of 0 for failure.
*/
static abi_long lock_iovec(int type, struct iovec *vec, abi_ulong target_addr,
int count, int copy)
{
struct target_iovec *target_vec;
abi_ulong base;
int i;
target_vec = lock_user(VERIFY_READ, target_addr, count * sizeof(struct target_iovec), 1);
if (!target_vec)
return -TARGET_EFAULT;
for (i = 0;i < count; i++) {
base = tswapl(target_vec[i].iov_base);
vec[i].iov_len = tswapl(target_vec[i].iov_len);
if (vec[i].iov_len != 0) {
vec[i].iov_base = lock_user(type, base, vec[i].iov_len, copy);
/* Don't check lock_user return value. We must call writev even
if a element has invalid base address. */
} else {
/* zero length pointer is ignored */
vec[i].iov_base = NULL;
}
}
unlock_user (target_vec, target_addr, 0);
return 0;
}
static abi_long unlock_iovec(struct iovec *vec, abi_ulong target_addr,
int count, int copy)
{
struct target_iovec *target_vec;
abi_ulong base;
int i;
target_vec = lock_user(VERIFY_READ, target_addr, count * sizeof(struct target_iovec), 1);
if (!target_vec)
return -TARGET_EFAULT;
for (i = 0;i < count; i++) {
if (target_vec[i].iov_base) {
base = tswapl(target_vec[i].iov_base);
unlock_user(vec[i].iov_base, base, copy ? vec[i].iov_len : 0);
}
}
unlock_user (target_vec, target_addr, 0);
return 0;
}
/* do_syscall() should always have a single exit point at the end so
that actions, such as logging of syscall results, can be performed.
All errnos that do_syscall() returns must be -TARGET_<errcode>. */
abi_long do_freebsd_syscall(void *cpu_env, int num, abi_long arg1,
abi_long arg2, abi_long arg3, abi_long arg4,
abi_long arg5, abi_long arg6, abi_long arg7,
abi_long arg8)
{
CPUState *cpu = env_cpu(cpu_env);
abi_long ret;
void *p;
#ifdef DEBUG
gemu_log("freebsd syscall %d\n", num);
#endif
record_syscall_start(cpu, num, arg1, arg2, arg3, arg4, arg5, arg6, 0, 0);
if (do_strace)
print_freebsd_syscall(num, arg1, arg2, arg3, arg4, arg5, arg6);
switch (num) {
case TARGET_FREEBSD_NR_exit:
#ifdef CONFIG_GPROF
_mcleanup();
#endif
gdb_exit(arg1);
qemu_plugin_user_exit();
/* XXX: should free thread stack and CPU env */
_exit(arg1);
ret = 0; /* avoid warning */
break;
case TARGET_FREEBSD_NR_read:
if (!(p = lock_user(VERIFY_WRITE, arg2, arg3, 0)))
goto efault;
ret = get_errno(read(arg1, p, arg3));
unlock_user(p, arg2, ret);
break;
case TARGET_FREEBSD_NR_write:
if (!(p = lock_user(VERIFY_READ, arg2, arg3, 1)))
goto efault;
ret = get_errno(write(arg1, p, arg3));
unlock_user(p, arg2, 0);
break;
case TARGET_FREEBSD_NR_writev:
{
int count = arg3;
struct iovec *vec;
vec = alloca(count * sizeof(struct iovec));
if (lock_iovec(VERIFY_READ, vec, arg2, count, 1) < 0)
goto efault;
ret = get_errno(writev(arg1, vec, count));
unlock_iovec(vec, arg2, count, 0);
}
break;
case TARGET_FREEBSD_NR_open:
if (!(p = lock_user_string(arg1)))
goto efault;
ret = get_errno(open(path(p),
target_to_host_bitmask(arg2, fcntl_flags_tbl),
arg3));
unlock_user(p, arg1, 0);
break;
case TARGET_FREEBSD_NR_mmap:
ret = get_errno(target_mmap(arg1, arg2, arg3,
target_to_host_bitmask(arg4, mmap_flags_tbl),
arg5,
arg6));
break;
case TARGET_FREEBSD_NR_mprotect:
ret = get_errno(target_mprotect(arg1, arg2, arg3));
break;
case TARGET_FREEBSD_NR_break:
ret = do_obreak(arg1);
break;
#ifdef __FreeBSD__
case TARGET_FREEBSD_NR___sysctl:
ret = do_freebsd_sysctl(arg1, arg2, arg3, arg4, arg5, arg6);
break;
#endif
case TARGET_FREEBSD_NR_sysarch:
ret = do_freebsd_sysarch(cpu_env, arg1, arg2);
break;
case TARGET_FREEBSD_NR_syscall:
case TARGET_FREEBSD_NR___syscall:
ret = do_freebsd_syscall(cpu_env,arg1 & 0xffff,arg2,arg3,arg4,arg5,arg6,arg7,arg8,0);
break;
default:
ret = get_errno(syscall(num, arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8));
break;
}
fail:
#ifdef DEBUG
gemu_log(" = %ld\n", ret);
#endif
if (do_strace)
print_freebsd_syscall_ret(num, ret);
record_syscall_return(cpu, num, ret);
return ret;
efault:
ret = -TARGET_EFAULT;
goto fail;
}
abi_long do_netbsd_syscall(void *cpu_env, int num, abi_long arg1,
abi_long arg2, abi_long arg3, abi_long arg4,
abi_long arg5, abi_long arg6)
{
CPUState *cpu = env_cpu(cpu_env);
abi_long ret;
void *p;
#ifdef DEBUG
gemu_log("netbsd syscall %d\n", num);
#endif
record_syscall_start(cpu, num, arg1, arg2, arg3, arg4, arg5, arg6, 0, 0);
if (do_strace)
print_netbsd_syscall(num, arg1, arg2, arg3, arg4, arg5, arg6);
switch (num) {
case TARGET_NETBSD_NR_exit:
#ifdef CONFIG_GPROF
_mcleanup();
#endif
gdb_exit(arg1);
qemu_plugin_user_exit();
/* XXX: should free thread stack and CPU env */
_exit(arg1);
ret = 0; /* avoid warning */
break;
case TARGET_NETBSD_NR_read:
if (!(p = lock_user(VERIFY_WRITE, arg2, arg3, 0)))
goto efault;
ret = get_errno(read(arg1, p, arg3));
unlock_user(p, arg2, ret);
break;
case TARGET_NETBSD_NR_write:
if (!(p = lock_user(VERIFY_READ, arg2, arg3, 1)))
goto efault;
ret = get_errno(write(arg1, p, arg3));
unlock_user(p, arg2, 0);
break;
case TARGET_NETBSD_NR_open:
if (!(p = lock_user_string(arg1)))
goto efault;
ret = get_errno(open(path(p),
target_to_host_bitmask(arg2, fcntl_flags_tbl),
arg3));
unlock_user(p, arg1, 0);
break;
case TARGET_NETBSD_NR_mmap:
ret = get_errno(target_mmap(arg1, arg2, arg3,
target_to_host_bitmask(arg4, mmap_flags_tbl),
arg5,
arg6));
break;
case TARGET_NETBSD_NR_mprotect:
ret = get_errno(target_mprotect(arg1, arg2, arg3));
break;
case TARGET_NETBSD_NR_syscall:
case TARGET_NETBSD_NR___syscall:
ret = do_netbsd_syscall(cpu_env,arg1 & 0xffff,arg2,arg3,arg4,arg5,arg6,0);
break;
default:
ret = syscall(num, arg1, arg2, arg3, arg4, arg5, arg6);
break;
}
fail:
#ifdef DEBUG
gemu_log(" = %ld\n", ret);
#endif
if (do_strace)
print_netbsd_syscall_ret(num, ret);
record_syscall_return(cpu, num, ret);
return ret;
efault:
ret = -TARGET_EFAULT;
goto fail;
}
abi_long do_openbsd_syscall(void *cpu_env, int num, abi_long arg1,
abi_long arg2, abi_long arg3, abi_long arg4,
abi_long arg5, abi_long arg6)
{
CPUState *cpu = env_cpu(cpu_env);
abi_long ret;
void *p;
#ifdef DEBUG
gemu_log("openbsd syscall %d\n", num);
#endif
record_syscall_start(cpu, num, arg1, arg2, arg3, arg4, arg5, arg6, 0, 0);
if (do_strace)
print_openbsd_syscall(num, arg1, arg2, arg3, arg4, arg5, arg6);
switch (num) {
case TARGET_OPENBSD_NR_exit:
#ifdef CONFIG_GPROF
_mcleanup();
#endif
gdb_exit(arg1);
qemu_plugin_user_exit();
/* XXX: should free thread stack and CPU env */
_exit(arg1);
ret = 0; /* avoid warning */
break;
case TARGET_OPENBSD_NR_read:
if (!(p = lock_user(VERIFY_WRITE, arg2, arg3, 0)))
goto efault;
ret = get_errno(read(arg1, p, arg3));
unlock_user(p, arg2, ret);
break;
case TARGET_OPENBSD_NR_write:
if (!(p = lock_user(VERIFY_READ, arg2, arg3, 1)))
goto efault;
ret = get_errno(write(arg1, p, arg3));
unlock_user(p, arg2, 0);
break;
case TARGET_OPENBSD_NR_open:
if (!(p = lock_user_string(arg1)))
goto efault;
ret = get_errno(open(path(p),
target_to_host_bitmask(arg2, fcntl_flags_tbl),
arg3));
unlock_user(p, arg1, 0);
break;
case TARGET_OPENBSD_NR_mmap:
ret = get_errno(target_mmap(arg1, arg2, arg3,
target_to_host_bitmask(arg4, mmap_flags_tbl),
arg5,
arg6));
break;
case TARGET_OPENBSD_NR_mprotect:
ret = get_errno(target_mprotect(arg1, arg2, arg3));
break;
case TARGET_OPENBSD_NR_syscall:
case TARGET_OPENBSD_NR___syscall:
ret = do_openbsd_syscall(cpu_env,arg1 & 0xffff,arg2,arg3,arg4,arg5,arg6,0);
break;
default:
ret = syscall(num, arg1, arg2, arg3, arg4, arg5, arg6);
break;
}
fail:
#ifdef DEBUG
gemu_log(" = %ld\n", ret);
#endif
if (do_strace)
print_openbsd_syscall_ret(num, ret);
record_syscall_return(cpu, num, ret);
return ret;
efault:
ret = -TARGET_EFAULT;
goto fail;
}
void syscall_init(void)
{
}
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