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freebsd-dev/sys/kern/init_main.c
Ed Schouten 814629dd64 Don't let cpu_set_syscall_retval() clobber exec_setregs(). 
Upon successful completion, the execve() system call invokes
exec_setregs() to initialize the registers of the initial thread of the
newly executed process. What is weird is that when execve() returns, it
still goes through the normal system call return path, clobbering the
registers with the system call's return value (td->td_retval).

Though this doesn't seem to be problematic for x86 most of the times (as
the value of eax/rax doesn't matter upon startup), this can be pretty
frustrating for architectures where function argument and return
registers overlap (e.g., ARM). On these systems, exec_setregs() also
needs to initialize td_retval.

Even worse are architectures where cpu_set_syscall_retval() sets
registers to values not derived from td_retval. On these architectures,
there is no way cpu_set_syscall_retval() can set registers to the way it
wants them to be upon the start of execution.

To get rid of this madness, let sys_execve() return EJUSTRETURN. This
will cause cpu_set_syscall_retval() to leave registers intact. This
makes process execution easier to understand. It also eliminates the
difference between execution of the initial process and successive ones.
The initial call to sys_execve() is not performed through a system call
context.

Reviewed by:	kib, jhibbits
Differential Revision:	https://reviews.freebsd.org/D13180
2017-11-24 07:35:08 +00:00

876 lines
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/*-
* SPDX-License-Identifier: BSD-4-Clause
*
* Copyright (c) 1995 Terrence R. Lambert
* All rights reserved.
*
* Copyright (c) 1982, 1986, 1989, 1991, 1992, 1993
* The Regents of the University of California. All rights reserved.
* (c) UNIX System Laboratories, Inc.
* All or some portions of this file are derived from material licensed
* to the University of California by American Telephone and Telegraph
* Co. or Unix System Laboratories, Inc. and are reproduced herein with
* the permission of UNIX System Laboratories, Inc.
*
* 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. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. 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.
*
* @(#)init_main.c 8.9 (Berkeley) 1/21/94
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_ddb.h"
#include "opt_init_path.h"
#include "opt_verbose_sysinit.h"
#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/exec.h>
#include <sys/file.h>
#include <sys/filedesc.h>
#include <sys/jail.h>
#include <sys/ktr.h>
#include <sys/lock.h>
#include <sys/loginclass.h>
#include <sys/mount.h>
#include <sys/mutex.h>
#include <sys/syscallsubr.h>
#include <sys/sysctl.h>
#include <sys/proc.h>
#include <sys/racct.h>
#include <sys/resourcevar.h>
#include <sys/systm.h>
#include <sys/signalvar.h>
#include <sys/vnode.h>
#include <sys/sysent.h>
#include <sys/reboot.h>
#include <sys/sched.h>
#include <sys/sx.h>
#include <sys/sysproto.h>
#include <sys/vmmeter.h>
#include <sys/unistd.h>
#include <sys/malloc.h>
#include <sys/conf.h>
#include <sys/cpuset.h>
#include <machine/cpu.h>
#include <security/audit/audit.h>
#include <security/mac/mac_framework.h>
#include <vm/vm.h>
#include <vm/vm_param.h>
#include <vm/pmap.h>
#include <vm/vm_map.h>
#include <vm/vm_domain.h>
#include <sys/copyright.h>
#include <ddb/ddb.h>
#include <ddb/db_sym.h>
void mi_startup(void); /* Should be elsewhere */
/* Components of the first process -- never freed. */
static struct session session0;
static struct pgrp pgrp0;
struct proc proc0;
struct thread0_storage thread0_st __aligned(32);
struct vmspace vmspace0;
struct proc *initproc;
#ifndef BOOTHOWTO
#define BOOTHOWTO 0
#endif
int boothowto = BOOTHOWTO; /* initialized so that it can be patched */
SYSCTL_INT(_debug, OID_AUTO, boothowto, CTLFLAG_RD, &boothowto, 0,
"Boot control flags, passed from loader");
#ifndef BOOTVERBOSE
#define BOOTVERBOSE 0
#endif
int bootverbose = BOOTVERBOSE;
SYSCTL_INT(_debug, OID_AUTO, bootverbose, CTLFLAG_RW, &bootverbose, 0,
"Control the output of verbose kernel messages");
#ifdef INVARIANTS
FEATURE(invariants, "Kernel compiled with INVARIANTS, may affect performance");
#endif
/*
* This ensures that there is at least one entry so that the sysinit_set
* symbol is not undefined. A sybsystem ID of SI_SUB_DUMMY is never
* executed.
*/
SYSINIT(placeholder, SI_SUB_DUMMY, SI_ORDER_ANY, NULL, NULL);
/*
* The sysinit table itself. Items are checked off as the are run.
* If we want to register new sysinit types, add them to newsysinit.
*/
SET_DECLARE(sysinit_set, struct sysinit);
struct sysinit **sysinit, **sysinit_end;
struct sysinit **newsysinit, **newsysinit_end;
EVENTHANDLER_LIST_DECLARE(process_init);
EVENTHANDLER_LIST_DECLARE(thread_init);
EVENTHANDLER_LIST_DECLARE(process_ctor);
EVENTHANDLER_LIST_DECLARE(thread_ctor);
/*
* Merge a new sysinit set into the current set, reallocating it if
* necessary. This can only be called after malloc is running.
*/
void
sysinit_add(struct sysinit **set, struct sysinit **set_end)
{
struct sysinit **newset;
struct sysinit **sipp;
struct sysinit **xipp;
int count;
count = set_end - set;
if (newsysinit)
count += newsysinit_end - newsysinit;
else
count += sysinit_end - sysinit;
newset = malloc(count * sizeof(*sipp), M_TEMP, M_NOWAIT);
if (newset == NULL)
panic("cannot malloc for sysinit");
xipp = newset;
if (newsysinit)
for (sipp = newsysinit; sipp < newsysinit_end; sipp++)
*xipp++ = *sipp;
else
for (sipp = sysinit; sipp < sysinit_end; sipp++)
*xipp++ = *sipp;
for (sipp = set; sipp < set_end; sipp++)
*xipp++ = *sipp;
if (newsysinit)
free(newsysinit, M_TEMP);
newsysinit = newset;
newsysinit_end = newset + count;
}
#if defined (DDB) && defined(VERBOSE_SYSINIT)
static const char *
symbol_name(vm_offset_t va, db_strategy_t strategy)
{
const char *name;
c_db_sym_t sym;
db_expr_t offset;
if (va == 0)
return (NULL);
sym = db_search_symbol(va, strategy, &offset);
if (offset != 0)
return (NULL);
db_symbol_values(sym, &name, NULL);
return (name);
}
#endif
/*
* System startup; initialize the world, create process 0, mount root
* filesystem, and fork to create init and pagedaemon. Most of the
* hard work is done in the lower-level initialization routines including
* startup(), which does memory initialization and autoconfiguration.
*
* This allows simple addition of new kernel subsystems that require
* boot time initialization. It also allows substitution of subsystem
* (for instance, a scheduler, kernel profiler, or VM system) by object
* module. Finally, it allows for optional "kernel threads".
*/
void
mi_startup(void)
{
struct sysinit **sipp; /* system initialization*/
struct sysinit **xipp; /* interior loop of sort*/
struct sysinit *save; /* bubble*/
#if defined(VERBOSE_SYSINIT)
int last;
int verbose;
#endif
if (boothowto & RB_VERBOSE)
bootverbose++;
if (sysinit == NULL) {
sysinit = SET_BEGIN(sysinit_set);
sysinit_end = SET_LIMIT(sysinit_set);
}
restart:
/*
* Perform a bubble sort of the system initialization objects by
* their subsystem (primary key) and order (secondary key).
*/
for (sipp = sysinit; sipp < sysinit_end; sipp++) {
for (xipp = sipp + 1; xipp < sysinit_end; xipp++) {
if ((*sipp)->subsystem < (*xipp)->subsystem ||
((*sipp)->subsystem == (*xipp)->subsystem &&
(*sipp)->order <= (*xipp)->order))
continue; /* skip*/
save = *sipp;
*sipp = *xipp;
*xipp = save;
}
}
#if defined(VERBOSE_SYSINIT)
last = SI_SUB_COPYRIGHT;
verbose = 0;
#if !defined(DDB)
printf("VERBOSE_SYSINIT: DDB not enabled, symbol lookups disabled.\n");
#endif
#endif
/*
* Traverse the (now) ordered list of system initialization tasks.
* Perform each task, and continue on to the next task.
*/
for (sipp = sysinit; sipp < sysinit_end; sipp++) {
if ((*sipp)->subsystem == SI_SUB_DUMMY)
continue; /* skip dummy task(s)*/
if ((*sipp)->subsystem == SI_SUB_DONE)
continue;
#if defined(VERBOSE_SYSINIT)
if ((*sipp)->subsystem > last) {
verbose = 1;
last = (*sipp)->subsystem;
printf("subsystem %x\n", last);
}
if (verbose) {
#if defined(DDB)
const char *func, *data;
func = symbol_name((vm_offset_t)(*sipp)->func,
DB_STGY_PROC);
data = symbol_name((vm_offset_t)(*sipp)->udata,
DB_STGY_ANY);
if (func != NULL && data != NULL)
printf(" %s(&%s)... ", func, data);
else if (func != NULL)
printf(" %s(%p)... ", func, (*sipp)->udata);
else
#endif
printf(" %p(%p)... ", (*sipp)->func,
(*sipp)->udata);
}
#endif
/* Call function */
(*((*sipp)->func))((*sipp)->udata);
#if defined(VERBOSE_SYSINIT)
if (verbose)
printf("done.\n");
#endif
/* Check off the one we're just done */
(*sipp)->subsystem = SI_SUB_DONE;
/* Check if we've installed more sysinit items via KLD */
if (newsysinit != NULL) {
if (sysinit != SET_BEGIN(sysinit_set))
free(sysinit, M_TEMP);
sysinit = newsysinit;
sysinit_end = newsysinit_end;
newsysinit = NULL;
newsysinit_end = NULL;
goto restart;
}
}
mtx_assert(&Giant, MA_OWNED | MA_NOTRECURSED);
mtx_unlock(&Giant);
/*
* Now hand over this thread to swapper.
*/
swapper();
/* NOTREACHED*/
}
static void
print_caddr_t(void *data)
{
printf("%s", (char *)data);
}
static void
print_version(void *data __unused)
{
int len;
/* Strip a trailing newline from version. */
len = strlen(version);
while (len > 0 && version[len - 1] == '\n')
len--;
printf("%.*s %s\n", len, version, machine);
printf("%s\n", compiler_version);
}
SYSINIT(announce, SI_SUB_COPYRIGHT, SI_ORDER_FIRST, print_caddr_t,
copyright);
SYSINIT(trademark, SI_SUB_COPYRIGHT, SI_ORDER_SECOND, print_caddr_t,
trademark);
SYSINIT(version, SI_SUB_COPYRIGHT, SI_ORDER_THIRD, print_version, NULL);
#ifdef WITNESS
static char wit_warn[] =
"WARNING: WITNESS option enabled, expect reduced performance.\n";
SYSINIT(witwarn, SI_SUB_COPYRIGHT, SI_ORDER_THIRD + 1,
print_caddr_t, wit_warn);
SYSINIT(witwarn2, SI_SUB_LAST, SI_ORDER_THIRD + 1,
print_caddr_t, wit_warn);
#endif
#ifdef DIAGNOSTIC
static char diag_warn[] =
"WARNING: DIAGNOSTIC option enabled, expect reduced performance.\n";
SYSINIT(diagwarn, SI_SUB_COPYRIGHT, SI_ORDER_THIRD + 2,
print_caddr_t, diag_warn);
SYSINIT(diagwarn2, SI_SUB_LAST, SI_ORDER_THIRD + 2,
print_caddr_t, diag_warn);
#endif
static int
null_fetch_syscall_args(struct thread *td __unused)
{
panic("null_fetch_syscall_args");
}
static void
null_set_syscall_retval(struct thread *td __unused, int error __unused)
{
panic("null_set_syscall_retval");
}
struct sysentvec null_sysvec = {
.sv_size = 0,
.sv_table = NULL,
.sv_mask = 0,
.sv_errsize = 0,
.sv_errtbl = NULL,
.sv_transtrap = NULL,
.sv_fixup = NULL,
.sv_sendsig = NULL,
.sv_sigcode = NULL,
.sv_szsigcode = NULL,
.sv_name = "null",
.sv_coredump = NULL,
.sv_imgact_try = NULL,
.sv_minsigstksz = 0,
.sv_pagesize = PAGE_SIZE,
.sv_minuser = VM_MIN_ADDRESS,
.sv_maxuser = VM_MAXUSER_ADDRESS,
.sv_usrstack = USRSTACK,
.sv_psstrings = PS_STRINGS,
.sv_stackprot = VM_PROT_ALL,
.sv_copyout_strings = NULL,
.sv_setregs = NULL,
.sv_fixlimit = NULL,
.sv_maxssiz = NULL,
.sv_flags = 0,
.sv_set_syscall_retval = null_set_syscall_retval,
.sv_fetch_syscall_args = null_fetch_syscall_args,
.sv_syscallnames = NULL,
.sv_schedtail = NULL,
.sv_thread_detach = NULL,
.sv_trap = NULL,
};
/*
* The two following SYSINIT's are proc0 specific glue code. I am not
* convinced that they can not be safely combined, but their order of
* operation has been maintained as the same as the original init_main.c
* for right now.
*/
/* ARGSUSED*/
static void
proc0_init(void *dummy __unused)
{
struct proc *p;
struct thread *td;
struct ucred *newcred;
struct uidinfo tmpuinfo;
struct loginclass tmplc = {
.lc_name = "",
};
vm_paddr_t pageablemem;
int i;
GIANT_REQUIRED;
p = &proc0;
td = &thread0;
/*
* Initialize magic number and osrel.
*/
p->p_magic = P_MAGIC;
p->p_osrel = osreldate;
/*
* Initialize thread and process structures.
*/
procinit(); /* set up proc zone */
threadinit(); /* set up UMA zones */
/*
* Initialise scheduler resources.
* Add scheduler specific parts to proc, thread as needed.
*/
schedinit(); /* scheduler gets its house in order */
/*
* Create process 0 (the swapper).
*/
LIST_INSERT_HEAD(&allproc, p, p_list);
LIST_INSERT_HEAD(PIDHASH(0), p, p_hash);
mtx_init(&pgrp0.pg_mtx, "process group", NULL, MTX_DEF | MTX_DUPOK);
p->p_pgrp = &pgrp0;
LIST_INSERT_HEAD(PGRPHASH(0), &pgrp0, pg_hash);
LIST_INIT(&pgrp0.pg_members);
LIST_INSERT_HEAD(&pgrp0.pg_members, p, p_pglist);
pgrp0.pg_session = &session0;
mtx_init(&session0.s_mtx, "session", NULL, MTX_DEF);
refcount_init(&session0.s_count, 1);
session0.s_leader = p;
p->p_sysent = &null_sysvec;
p->p_flag = P_SYSTEM | P_INMEM | P_KPROC;
p->p_flag2 = 0;
p->p_state = PRS_NORMAL;
p->p_klist = knlist_alloc(&p->p_mtx);
STAILQ_INIT(&p->p_ktr);
p->p_nice = NZERO;
/* pid_max cannot be greater than PID_MAX */
td->td_tid = PID_MAX + 1;
LIST_INSERT_HEAD(TIDHASH(td->td_tid), td, td_hash);
td->td_state = TDS_RUNNING;
td->td_pri_class = PRI_TIMESHARE;
td->td_user_pri = PUSER;
td->td_base_user_pri = PUSER;
td->td_lend_user_pri = PRI_MAX;
td->td_priority = PVM;
td->td_base_pri = PVM;
td->td_oncpu = curcpu;
td->td_flags = TDF_INMEM;
td->td_pflags = TDP_KTHREAD;
td->td_cpuset = cpuset_thread0();
vm_domain_policy_init(&td->td_vm_dom_policy);
vm_domain_policy_set(&td->td_vm_dom_policy, VM_POLICY_NONE, -1);
vm_domain_policy_init(&p->p_vm_dom_policy);
vm_domain_policy_set(&p->p_vm_dom_policy, VM_POLICY_NONE, -1);
prison0_init();
p->p_peers = 0;
p->p_leader = p;
p->p_reaper = p;
LIST_INIT(&p->p_reaplist);
strncpy(p->p_comm, "kernel", sizeof (p->p_comm));
strncpy(td->td_name, "swapper", sizeof (td->td_name));
callout_init_mtx(&p->p_itcallout, &p->p_mtx, 0);
callout_init_mtx(&p->p_limco, &p->p_mtx, 0);
callout_init(&td->td_slpcallout, 1);
/* Create credentials. */
newcred = crget();
newcred->cr_ngroups = 1; /* group 0 */
/* A hack to prevent uifind from tripping over NULL pointers. */
curthread->td_ucred = newcred;
tmpuinfo.ui_uid = 1;
newcred->cr_uidinfo = newcred->cr_ruidinfo = &tmpuinfo;
newcred->cr_uidinfo = uifind(0);
newcred->cr_ruidinfo = uifind(0);
newcred->cr_loginclass = &tmplc;
newcred->cr_loginclass = loginclass_find("default");
/* End hack. creds get properly set later with thread_cow_get_proc */
curthread->td_ucred = NULL;
newcred->cr_prison = &prison0;
proc_set_cred_init(p, newcred);
#ifdef AUDIT
audit_cred_kproc0(newcred);
#endif
#ifdef MAC
mac_cred_create_swapper(newcred);
#endif
/* Create sigacts. */
p->p_sigacts = sigacts_alloc();
/* Initialize signal state for process 0. */
siginit(&proc0);
/* Create the file descriptor table. */
p->p_fd = fdinit(NULL, false);
p->p_fdtol = NULL;
/* Create the limits structures. */
p->p_limit = lim_alloc();
for (i = 0; i < RLIM_NLIMITS; i++)
p->p_limit->pl_rlimit[i].rlim_cur =
p->p_limit->pl_rlimit[i].rlim_max = RLIM_INFINITY;
p->p_limit->pl_rlimit[RLIMIT_NOFILE].rlim_cur =
p->p_limit->pl_rlimit[RLIMIT_NOFILE].rlim_max = maxfiles;
p->p_limit->pl_rlimit[RLIMIT_NPROC].rlim_cur =
p->p_limit->pl_rlimit[RLIMIT_NPROC].rlim_max = maxproc;
p->p_limit->pl_rlimit[RLIMIT_DATA].rlim_cur = dfldsiz;
p->p_limit->pl_rlimit[RLIMIT_DATA].rlim_max = maxdsiz;
p->p_limit->pl_rlimit[RLIMIT_STACK].rlim_cur = dflssiz;
p->p_limit->pl_rlimit[RLIMIT_STACK].rlim_max = maxssiz;
/* Cast to avoid overflow on i386/PAE. */
pageablemem = ptoa((vm_paddr_t)vm_cnt.v_free_count);
p->p_limit->pl_rlimit[RLIMIT_RSS].rlim_cur =
p->p_limit->pl_rlimit[RLIMIT_RSS].rlim_max = pageablemem;
p->p_limit->pl_rlimit[RLIMIT_MEMLOCK].rlim_cur = pageablemem / 3;
p->p_limit->pl_rlimit[RLIMIT_MEMLOCK].rlim_max = pageablemem;
p->p_cpulimit = RLIM_INFINITY;
PROC_LOCK(p);
thread_cow_get_proc(td, p);
PROC_UNLOCK(p);
/* Initialize resource accounting structures. */
racct_create(&p->p_racct);
p->p_stats = pstats_alloc();
/* Allocate a prototype map so we have something to fork. */
p->p_vmspace = &vmspace0;
vmspace0.vm_refcnt = 1;
pmap_pinit0(vmspace_pmap(&vmspace0));
/*
* proc0 is not expected to enter usermode, so there is no special
* handling for sv_minuser here, like is done for exec_new_vmspace().
*/
vm_map_init(&vmspace0.vm_map, vmspace_pmap(&vmspace0),
p->p_sysent->sv_minuser, p->p_sysent->sv_maxuser);
/*
* Call the init and ctor for the new thread and proc. We wait
* to do this until all other structures are fairly sane.
*/
EVENTHANDLER_DIRECT_INVOKE(process_init, p);
EVENTHANDLER_DIRECT_INVOKE(thread_init, td);
EVENTHANDLER_DIRECT_INVOKE(process_ctor, p);
EVENTHANDLER_DIRECT_INVOKE(thread_ctor, td);
/*
* Charge root for one process.
*/
(void)chgproccnt(p->p_ucred->cr_ruidinfo, 1, 0);
PROC_LOCK(p);
racct_add_force(p, RACCT_NPROC, 1);
PROC_UNLOCK(p);
}
SYSINIT(p0init, SI_SUB_INTRINSIC, SI_ORDER_FIRST, proc0_init, NULL);
/* ARGSUSED*/
static void
proc0_post(void *dummy __unused)
{
struct timespec ts;
struct proc *p;
struct rusage ru;
struct thread *td;
/*
* Now we can look at the time, having had a chance to verify the
* time from the filesystem. Pretend that proc0 started now.
*/
sx_slock(&allproc_lock);
FOREACH_PROC_IN_SYSTEM(p) {
microuptime(&p->p_stats->p_start);
PROC_STATLOCK(p);
rufetch(p, &ru); /* Clears thread stats */
PROC_STATUNLOCK(p);
p->p_rux.rux_runtime = 0;
p->p_rux.rux_uticks = 0;
p->p_rux.rux_sticks = 0;
p->p_rux.rux_iticks = 0;
FOREACH_THREAD_IN_PROC(p, td) {
td->td_runtime = 0;
}
}
sx_sunlock(&allproc_lock);
PCPU_SET(switchtime, cpu_ticks());
PCPU_SET(switchticks, ticks);
/*
* Give the ``random'' number generator a thump.
*/
nanotime(&ts);
srandom(ts.tv_sec ^ ts.tv_nsec);
}
SYSINIT(p0post, SI_SUB_INTRINSIC_POST, SI_ORDER_FIRST, proc0_post, NULL);
static void
random_init(void *dummy __unused)
{
/*
* After CPU has been started we have some randomness on most
* platforms via get_cyclecount(). For platforms that don't
* we will reseed random(9) in proc0_post() as well.
*/
srandom(get_cyclecount());
}
SYSINIT(random, SI_SUB_RANDOM, SI_ORDER_FIRST, random_init, NULL);
/*
***************************************************************************
****
**** The following SYSINIT's and glue code should be moved to the
**** respective files on a per subsystem basis.
****
***************************************************************************
*/
/*
* List of paths to try when searching for "init".
*/
static char init_path[MAXPATHLEN] =
#ifdef INIT_PATH
__XSTRING(INIT_PATH);
#else
"/sbin/init:/sbin/oinit:/sbin/init.bak:/rescue/init";
#endif
SYSCTL_STRING(_kern, OID_AUTO, init_path, CTLFLAG_RD, init_path, 0,
"Path used to search the init process");
/*
* Shutdown timeout of init(8).
* Unused within kernel, but used to control init(8), hence do not remove.
*/
#ifndef INIT_SHUTDOWN_TIMEOUT
#define INIT_SHUTDOWN_TIMEOUT 120
#endif
static int init_shutdown_timeout = INIT_SHUTDOWN_TIMEOUT;
SYSCTL_INT(_kern, OID_AUTO, init_shutdown_timeout,
CTLFLAG_RW, &init_shutdown_timeout, 0, "Shutdown timeout of init(8). "
"Unused within kernel, but used to control init(8)");
/*
* Start the initial user process; try exec'ing each pathname in init_path.
* The program is invoked with one argument containing the boot flags.
*/
static void
start_init(void *dummy)
{
vm_offset_t addr;
struct execve_args args;
int options, error;
char *var, *path, *next, *s;
char *ucp, **uap, *arg0, *arg1;
struct thread *td;
struct proc *p;
mtx_lock(&Giant);
GIANT_REQUIRED;
td = curthread;
p = td->td_proc;
vfs_mountroot();
/* Wipe GELI passphrase from the environment. */
kern_unsetenv("kern.geom.eli.passphrase");
/*
* Need just enough stack to hold the faked-up "execve()" arguments.
*/
addr = p->p_sysent->sv_usrstack - PAGE_SIZE;
if (vm_map_find(&p->p_vmspace->vm_map, NULL, 0, &addr, PAGE_SIZE, 0,
VMFS_NO_SPACE, VM_PROT_ALL, VM_PROT_ALL, 0) != 0)
panic("init: couldn't allocate argument space");
p->p_vmspace->vm_maxsaddr = (caddr_t)addr;
p->p_vmspace->vm_ssize = 1;
if ((var = kern_getenv("init_path")) != NULL) {
strlcpy(init_path, var, sizeof(init_path));
freeenv(var);
}
for (path = init_path; *path != '\0'; path = next) {
while (*path == ':')
path++;
if (*path == '\0')
break;
for (next = path; *next != '\0' && *next != ':'; next++)
/* nothing */ ;
if (bootverbose)
printf("start_init: trying %.*s\n", (int)(next - path),
path);
/*
* Move out the boot flag argument.
*/
options = 0;
ucp = (char *)p->p_sysent->sv_usrstack;
(void)subyte(--ucp, 0); /* trailing zero */
if (boothowto & RB_SINGLE) {
(void)subyte(--ucp, 's');
options = 1;
}
#ifdef notyet
if (boothowto & RB_FASTBOOT) {
(void)subyte(--ucp, 'f');
options = 1;
}
#endif
#ifdef BOOTCDROM
(void)subyte(--ucp, 'C');
options = 1;
#endif
if (options == 0)
(void)subyte(--ucp, '-');
(void)subyte(--ucp, '-'); /* leading hyphen */
arg1 = ucp;
/*
* Move out the file name (also arg 0).
*/
(void)subyte(--ucp, 0);
for (s = next - 1; s >= path; s--)
(void)subyte(--ucp, *s);
arg0 = ucp;
/*
* Move out the arg pointers.
*/
uap = (char **)rounddown2((intptr_t)ucp, sizeof(intptr_t));
(void)suword((caddr_t)--uap, (long)0); /* terminator */
(void)suword((caddr_t)--uap, (long)(intptr_t)arg1);
(void)suword((caddr_t)--uap, (long)(intptr_t)arg0);
/*
* Point at the arguments.
*/
args.fname = arg0;
args.argv = uap;
args.envv = NULL;
/*
* Now try to exec the program. If can't for any reason
* other than it doesn't exist, complain.
*
* Otherwise, return via fork_trampoline() all the way
* to user mode as init!
*/
if ((error = sys_execve(td, &args)) == EJUSTRETURN) {
mtx_unlock(&Giant);
return;
}
if (error != ENOENT)
printf("exec %.*s: error %d\n", (int)(next - path),
path, error);
}
printf("init: not found in path %s\n", init_path);
panic("no init");
}
/*
* Like kproc_create(), but runs in its own address space.
* We do this early to reserve pid 1.
*
* Note special case - do not make it runnable yet. Other work
* in progress will change this more.
*/
static void
create_init(const void *udata __unused)
{
struct fork_req fr;
struct ucred *newcred, *oldcred;
struct thread *td;
int error;
bzero(&fr, sizeof(fr));
fr.fr_flags = RFFDG | RFPROC | RFSTOPPED;
fr.fr_procp = &initproc;
error = fork1(&thread0, &fr);
if (error)
panic("cannot fork init: %d\n", error);
KASSERT(initproc->p_pid == 1, ("create_init: initproc->p_pid != 1"));
/* divorce init's credentials from the kernel's */
newcred = crget();
sx_xlock(&proctree_lock);
PROC_LOCK(initproc);
initproc->p_flag |= P_SYSTEM | P_INMEM;
initproc->p_treeflag |= P_TREE_REAPER;
LIST_INSERT_HEAD(&initproc->p_reaplist, &proc0, p_reapsibling);
oldcred = initproc->p_ucred;
crcopy(newcred, oldcred);
#ifdef MAC
mac_cred_create_init(newcred);
#endif
#ifdef AUDIT
audit_cred_proc1(newcred);
#endif
proc_set_cred(initproc, newcred);
td = FIRST_THREAD_IN_PROC(initproc);
crfree(td->td_ucred);
td->td_ucred = crhold(initproc->p_ucred);
PROC_UNLOCK(initproc);
sx_xunlock(&proctree_lock);
crfree(oldcred);
cpu_fork_kthread_handler(FIRST_THREAD_IN_PROC(initproc),
start_init, NULL);
}
SYSINIT(init, SI_SUB_CREATE_INIT, SI_ORDER_FIRST, create_init, NULL);
/*
* Make it runnable now.
*/
static void
kick_init(const void *udata __unused)
{
struct thread *td;
td = FIRST_THREAD_IN_PROC(initproc);
thread_lock(td);
TD_SET_CAN_RUN(td);
sched_add(td, SRQ_BORING);
thread_unlock(td);
}
SYSINIT(kickinit, SI_SUB_KTHREAD_INIT, SI_ORDER_MIDDLE, kick_init, NULL);
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