OpenSolaris_b135/uts/common/os/core.c
/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright 2008 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
/* Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
/* All Rights Reserved */
#include <sys/param.h>
#include <sys/types.h>
#include <sys/time.h>
#include <sys/sysmacros.h>
#include <sys/proc.h>
#include <sys/systm.h>
#include <sys/cred.h>
#include <sys/user.h>
#include <sys/utsname.h>
#include <sys/errno.h>
#include <sys/signal.h>
#include <sys/siginfo.h>
#include <sys/fault.h>
#include <sys/syscall.h>
#include <sys/ucontext.h>
#include <sys/prsystm.h>
#include <sys/vnode.h>
#include <sys/var.h>
#include <sys/file.h>
#include <sys/pathname.h>
#include <sys/vfs.h>
#include <sys/exec.h>
#include <sys/debug.h>
#include <sys/stack.h>
#include <sys/kmem.h>
#include <sys/schedctl.h>
#include <sys/core.h>
#include <sys/corectl.h>
#include <sys/cmn_err.h>
#include <vm/as.h>
#include <sys/rctl.h>
#include <sys/nbmlock.h>
#include <sys/stat.h>
#include <sys/zone.h>
#include <sys/contract/process_impl.h>
#include <sys/ddi.h>
/*
* Processes running within a zone potentially dump core in 3 locations,
* based on the per-process, per-zone, and the global zone's core settings.
*
* Per-zone and global zone settings are often referred to as "global"
* settings since they apply to the system (or zone) as a whole, as
* opposed to a particular process.
*/
enum core_types {
CORE_PROC, /* Use per-process settings */
CORE_ZONE, /* Use per-zone settings */
CORE_GLOBAL /* Use global zone settings */
};
/*
* Log information about "global" core dumps to syslog.
*/
static void
core_log(struct core_globals *cg, int error, const char *why, const char *path,
zoneid_t zoneid)
{
proc_t *p = curproc;
pid_t pid = p->p_pid;
char *fn = PTOU(p)->u_comm;
if (!(cg->core_options & CC_GLOBAL_LOG))
return;
if (path == NULL)
zcmn_err(zoneid, CE_NOTE, "core_log: %s[%d] %s", fn, pid, why);
else if (error == 0)
zcmn_err(zoneid, CE_NOTE, "core_log: %s[%d] %s: %s", fn, pid,
why, path);
else
zcmn_err(zoneid, CE_NOTE, "core_log: %s[%d] %s, errno=%d: %s",
fn, pid, why, error, path);
}
/*
* Private version of vn_remove().
* Refuse to unlink a directory or an unwritable file.
* Also allow the process to access files normally inaccessible due to
* chroot(2) or Zone limitations.
*/
static int
remove_core_file(char *fp, enum core_types core_type)
{
vnode_t *vp = NULL; /* entry vnode */
vnode_t *dvp; /* ptr to parent dir vnode */
vfs_t *dvfsp;
int error;
int in_crit = 0;
pathname_t pn; /* name of entry */
vnode_t *startvp, *rootvp;
if ((error = pn_get(fp, UIO_SYSSPACE, &pn)) != 0)
return (error);
/*
* Determine what rootvp to use.
*/
if (core_type == CORE_PROC) {
rootvp = (PTOU(curproc)->u_rdir == NULL ?
curproc->p_zone->zone_rootvp : PTOU(curproc)->u_rdir);
startvp = (fp[0] == '/' ? rootvp : PTOU(curproc)->u_cdir);
} else if (core_type == CORE_ZONE) {
startvp = curproc->p_zone->zone_rootvp;
rootvp = curproc->p_zone->zone_rootvp;
} else {
ASSERT(core_type == CORE_GLOBAL);
startvp = rootdir;
rootvp = rootdir;
}
VN_HOLD(startvp);
if (rootvp != rootdir)
VN_HOLD(rootvp);
if ((error = lookuppnvp(&pn, NULL, NO_FOLLOW, &dvp, &vp, rootvp,
startvp, CRED())) != 0) {
pn_free(&pn);
return (error);
}
/*
* Succeed if there is no file.
* Fail if the file is not a regular file.
* Fail if the filesystem is mounted read-only.
* Fail if the file is not writeable.
* Fail if the file has NBMAND share reservations.
*/
if (vp == NULL)
error = 0;
else if (vp->v_type != VREG)
error = EACCES;
else if ((dvfsp = dvp->v_vfsp) != NULL &&
(dvfsp->vfs_flag & VFS_RDONLY))
error = EROFS;
else if ((error = VOP_ACCESS(vp, VWRITE, 0, CRED(), NULL)) == 0) {
if (nbl_need_check(vp)) {
nbl_start_crit(vp, RW_READER);
in_crit = 1;
if (nbl_share_conflict(vp, NBL_REMOVE, NULL)) {
error = EACCES;
}
}
if (!error) {
error = VOP_REMOVE(dvp, pn.pn_path, CRED(), NULL, 0);
}
}
pn_free(&pn);
if (vp != NULL) {
if (in_crit)
nbl_end_crit(vp);
VN_RELE(vp);
}
VN_RELE(dvp);
return (error);
}
/*
* Create the core file in a location that may be normally inaccessible due
* to chroot(2) or Zone limitations.
*/
static int
create_core_file(char *fp, enum core_types core_type, vnode_t **vpp)
{
int error;
mode_t perms = (S_IRUSR | S_IWUSR);
pathname_t pn;
char *file;
vnode_t *vp;
vnode_t *dvp;
vattr_t vattr;
cred_t *credp = CRED();
if (core_type == CORE_PROC) {
file = fp;
dvp = NULL; /* regular lookup */
} else {
vnode_t *startvp, *rootvp;
ASSERT(core_type == CORE_ZONE || core_type == CORE_GLOBAL);
/*
* This is tricky because we want to dump the core in
* a location which may normally be inaccessible
* to us (due to chroot(2) limitations, or zone
* membership), and hence need to overcome u_rdir
* restrictions. The basic idea is to separate
* the path from the filename, lookup the
* pathname separately (starting from the global
* zone's root directory), and then open the
* file starting at the directory vnode.
*/
if (error = pn_get(fp, UIO_SYSSPACE, &pn))
return (error);
if (core_type == CORE_ZONE) {
startvp = rootvp = curproc->p_zone->zone_rootvp;
} else {
startvp = rootvp = rootdir;
}
/*
* rootvp and startvp will be VN_RELE()'d by lookuppnvp() if
* necessary.
*/
VN_HOLD(startvp);
if (rootvp != rootdir)
VN_HOLD(rootvp);
/*
* Do a lookup on the full path, ignoring the actual file, but
* finding the vnode for the directory. It's OK if the file
* doesn't exist -- it most likely won't since we just removed
* it.
*/
error = lookuppnvp(&pn, NULL, FOLLOW, &dvp, NULLVPP,
rootvp, startvp, credp);
pn_free(&pn);
if (error != 0)
return (error);
ASSERT(dvp != NULL);
/*
* Now find the final component in the path (ie, the name of
* the core file).
*/
if (error = pn_get(fp, UIO_SYSSPACE, &pn)) {
VN_RELE(dvp);
return (error);
}
pn_setlast(&pn);
file = pn.pn_path;
}
error = vn_openat(file, UIO_SYSSPACE,
FWRITE | FTRUNC | FEXCL | FCREAT | FOFFMAX,
perms, &vp, CRCREAT, PTOU(curproc)->u_cmask, dvp, -1);
if (core_type != CORE_PROC) {
VN_RELE(dvp);
pn_free(&pn);
}
/*
* Don't dump a core file owned by "nobody".
*/
vattr.va_mask = AT_UID;
if (error == 0 &&
(VOP_GETATTR(vp, &vattr, 0, credp, NULL) != 0 ||
vattr.va_uid != crgetuid(credp))) {
(void) VOP_CLOSE(vp, FWRITE, 1, (offset_t)0,
credp, NULL);
VN_RELE(vp);
(void) remove_core_file(fp, core_type);
error = EACCES;
}
*vpp = vp;
return (error);
}
/*
* Install the specified held cred into the process, and return a pointer to
* the held cred which was previously the value of p->p_cred.
*/
static cred_t *
set_cred(proc_t *p, cred_t *newcr)
{
cred_t *oldcr;
uid_t olduid, newuid;
/*
* Place a hold on the existing cred, and then install the new
* cred into the proc structure.
*/
mutex_enter(&p->p_crlock);
oldcr = p->p_cred;
crhold(oldcr);
p->p_cred = newcr;
mutex_exit(&p->p_crlock);
ASSERT(crgetzoneid(oldcr) == crgetzoneid(newcr));
/*
* If the real uid is changing, keep the per-user process
* counts accurate.
*/
olduid = crgetruid(oldcr);
newuid = crgetruid(newcr);
if (olduid != newuid) {
zoneid_t zoneid = crgetzoneid(newcr);
mutex_enter(&pidlock);
upcount_dec(olduid, zoneid);
upcount_inc(newuid, zoneid);
mutex_exit(&pidlock);
}
/*
* Broadcast the new cred to all the other threads. The old
* cred can be safely returned because we have a hold on it.
*/
crset(p, newcr);
return (oldcr);
}
static int
do_core(char *fp, int sig, enum core_types core_type, struct core_globals *cg)
{
proc_t *p = curproc;
cred_t *credp = CRED();
rlim64_t rlimit;
vnode_t *vp;
int error = 0;
struct execsw *eswp;
cred_t *ocredp = NULL;
int is_setid = 0;
core_content_t content;
uid_t uid;
gid_t gid;
if (core_type == CORE_GLOBAL || core_type == CORE_ZONE) {
mutex_enter(&cg->core_lock);
content = cg->core_content;
mutex_exit(&cg->core_lock);
rlimit = cg->core_rlimit;
} else {
mutex_enter(&p->p_lock);
rlimit = rctl_enforced_value(rctlproc_legacy[RLIMIT_CORE],
p->p_rctls, p);
content = corectl_content_value(p->p_content);
mutex_exit(&p->p_lock);
}
if (rlimit == 0)
return (EFBIG);
/*
* If SNOCD is set, or if the effective, real, and saved ids do
* not match up, no one but a privileged user is allowed to view
* this core file. Set the credentials and the owner to root.
*/
if ((p->p_flag & SNOCD) ||
(uid = crgetuid(credp)) != crgetruid(credp) ||
uid != crgetsuid(credp) ||
(gid = crgetgid(credp)) != crgetrgid(credp) ||
gid != crgetsgid(credp)) {
/*
* Because this is insecure against certain forms of file
* system attack, do it only if set-id core files have been
* enabled via corectl(CC_GLOBAL_SETID | CC_PROCESS_SETID).
*/
if (((core_type == CORE_GLOBAL || core_type == CORE_ZONE) &&
!(cg->core_options & CC_GLOBAL_SETID)) ||
(core_type == CORE_PROC &&
!(cg->core_options & CC_PROCESS_SETID)))
return (ENOTSUP);
is_setid = 1;
}
/*
* If we are doing a "global" core dump or a set-id core dump,
* use kcred to do the dumping.
*/
if (core_type == CORE_GLOBAL || core_type == CORE_ZONE || is_setid) {
/*
* Use the zone's "kcred" to prevent privilege
* escalation.
*/
credp = zone_get_kcred(getzoneid());
ASSERT(credp != NULL);
ocredp = set_cred(p, credp);
}
/*
* First remove any existing core file, then
* open the new core file with (O_EXCL|O_CREAT).
*
* The reasons for doing this are manifold:
*
* For security reasons, we don't want root processes
* to dump core through a symlink because that would
* allow a malicious user to clobber any file on
* the system if s/he could convince a root process,
* perhaps a set-uid root process that s/he started,
* to dump core in a directory writable by that user.
* Similar security reasons apply to hard links.
* For symmetry we do this unconditionally, not
* just for root processes.
*
* If the process has the core file mmap()d into the
* address space, we would be modifying the address
* space that we are trying to dump if we did not first
* remove the core file. (The command "file core"
* is the canonical example of this possibility.)
*
* Opening the core file with O_EXCL|O_CREAT ensures than
* two concurrent core dumps don't clobber each other.
* One is bound to lose; we don't want to make both lose.
*/
if ((error = remove_core_file(fp, core_type)) == 0) {
error = create_core_file(fp, core_type, &vp);
}
/*
* Now that vn_open is complete, reset the process's credentials if
* we changed them, and make 'credp' point to kcred used
* above. We use 'credp' to do i/o on the core file below, but leave
* p->p_cred set to the original credential to allow the core file
* to record this information.
*/
if (ocredp != NULL)
credp = set_cred(p, ocredp);
if (error == 0) {
int closerr;
#if defined(__sparc)
(void) flush_user_windows_to_stack(NULL);
#endif
#ifdef SUN_SRC_COMPAT
PTOU(curproc)->u_acflag |= ACORE;
#endif
if ((eswp = PTOU(curproc)->u_execsw) == NULL ||
(eswp = findexec_by_magic(eswp->exec_magic)) == NULL) {
error = ENOSYS;
} else {
error = eswp->exec_core(vp, p, credp, rlimit, sig,
content);
rw_exit(eswp->exec_lock);
}
closerr = VOP_CLOSE(vp, FWRITE, 1, (offset_t)0, credp, NULL);
VN_RELE(vp);
if (error == 0)
error = closerr;
}
if (ocredp != NULL)
crfree(credp);
return (error);
}
/*
* Convert a core name pattern to a pathname.
*/
static int
expand_string(const char *pat, char *fp, int size, cred_t *cr)
{
proc_t *p = curproc;
char buf[24];
int len, i;
char *s;
char c;
while ((c = *pat++) != '\0') {
if (size < 2)
return (ENAMETOOLONG);
if (c != '%') {
size--;
*fp++ = c;
continue;
}
if ((c = *pat++) == '\0') {
size--;
*fp++ = '%';
break;
}
switch (c) {
case 'p': /* pid */
(void) sprintf((s = buf), "%d", p->p_pid);
break;
case 'u': /* effective uid */
(void) sprintf((s = buf), "%u", crgetuid(p->p_cred));
break;
case 'g': /* effective gid */
(void) sprintf((s = buf), "%u", crgetgid(p->p_cred));
break;
case 'f': /* exec'd filename */
s = PTOU(p)->u_comm;
break;
case 'd': /* exec'd dirname */
/*
* Even if pathname caching is disabled, we should
* be able to lookup the pathname for a directory.
*/
if (p->p_execdir != NULL && vnodetopath(NULL,
p->p_execdir, fp, size, cr) == 0) {
len = (int)strlen(fp);
ASSERT(len < size);
ASSERT(len >= 1);
ASSERT(fp[0] == '/');
/*
* Strip off the leading slash.
*/
for (i = 0; i < len; i++) {
fp[i] = fp[i + 1];
}
len--;
size -= len;
fp += len;
} else {
*fp = '\0';
}
continue;
case 'n': /* system nodename */
s = uts_nodename();
break;
case 'm': /* machine (sun4u, etc) */
s = utsname.machine;
break;
case 't': /* decimal value of time(2) */
(void) sprintf((s = buf), "%ld", gethrestime_sec());
break;
case 'z':
s = p->p_zone->zone_name;
break;
case '%':
(void) strcpy((s = buf), "%");
break;
default:
s = buf;
buf[0] = '%';
buf[1] = c;
buf[2] = '\0';
break;
}
len = (int)strlen(s);
if ((size -= len) <= 0)
return (ENAMETOOLONG);
(void) strcpy(fp, s);
fp += len;
}
*fp = '\0';
return (0);
}
static int
dump_one_core(int sig, rlim64_t rlimit, enum core_types core_type,
struct core_globals *cg, char **name)
{
refstr_t *rp;
proc_t *p = curproc;
zoneid_t zoneid;
int error;
char *fp;
cred_t *cr;
ASSERT(core_type == CORE_ZONE || core_type == CORE_GLOBAL);
zoneid = (core_type == CORE_ZONE ? getzoneid() : GLOBAL_ZONEID);
mutex_enter(&cg->core_lock);
if ((rp = cg->core_file) != NULL)
refstr_hold(rp);
mutex_exit(&cg->core_lock);
if (rp == NULL) {
core_log(cg, 0, "no global core file pattern exists", NULL,
zoneid);
return (1); /* core file not generated */
}
fp = kmem_alloc(MAXPATHLEN, KM_SLEEP);
cr = zone_get_kcred(getzoneid());
error = expand_string(refstr_value(rp), fp, MAXPATHLEN, cr);
crfree(cr);
if (error != 0) {
core_log(cg, 0, "global core file pattern too long",
refstr_value(rp), zoneid);
} else if ((error = do_core(fp, sig, core_type, cg)) == 0) {
core_log(cg, 0, "core dumped", fp, zoneid);
} else if (error == ENOTSUP) {
core_log(cg, 0, "setid process, core not dumped", fp, zoneid);
} else if (error == ENOSPC) {
core_log(cg, 0, "no space left on device, core truncated",
fp, zoneid);
} else if (error == EFBIG) {
if (rlimit == 0)
core_log(cg, 0, "core rlimit is zero, core not dumped",
fp, zoneid);
else
core_log(cg, 0, "core rlimit exceeded, core truncated",
fp, zoneid);
/*
* In addition to the core result logging, we
* may also have explicit actions defined on
* core file size violations via the resource
* control framework.
*/
mutex_enter(&p->p_lock);
(void) rctl_action(rctlproc_legacy[RLIMIT_CORE],
p->p_rctls, p, RCA_SAFE);
mutex_exit(&p->p_lock);
} else {
core_log(cg, error, "core dump failed", fp, zoneid);
}
refstr_rele(rp);
if (name != NULL)
*name = fp;
else
kmem_free(fp, MAXPATHLEN);
return (error);
}
int
core(int sig, int ext)
{
proc_t *p = curproc;
klwp_t *lwp = ttolwp(curthread);
refstr_t *rp;
char *fp_process = NULL, *fp_global = NULL, *fp_zone = NULL;
int error1 = 1;
int error2 = 1;
int error3 = 1;
k_sigset_t sigmask;
k_sigset_t sighold;
rlim64_t rlimit;
struct core_globals *my_cg, *global_cg;
global_cg = zone_getspecific(core_zone_key, global_zone);
ASSERT(global_cg != NULL);
my_cg = zone_getspecific(core_zone_key, curproc->p_zone);
ASSERT(my_cg != NULL);
/* core files suppressed? */
if (!(my_cg->core_options & (CC_PROCESS_PATH|CC_GLOBAL_PATH)) &&
!(global_cg->core_options & CC_GLOBAL_PATH)) {
if (!ext && p->p_ct_process != NULL)
contract_process_core(p->p_ct_process, p, sig,
NULL, NULL, NULL);
return (1);
}
/*
* Block all signals except SIGHUP, SIGINT, SIGKILL, and SIGTERM.
* These signals are allowed to interrupt the core dump.
* SIGQUIT is not allowed because it is supposed to make a core.
* Additionally, get current limit on core file size for handling later
* error reporting.
*/
mutex_enter(&p->p_lock);
p->p_flag |= SDOCORE;
schedctl_finish_sigblock(curthread);
sigmask = curthread->t_hold; /* remember for later */
sigfillset(&sighold);
if (!sigismember(&sigmask, SIGHUP))
sigdelset(&sighold, SIGHUP);
if (!sigismember(&sigmask, SIGINT))
sigdelset(&sighold, SIGINT);
if (!sigismember(&sigmask, SIGKILL))
sigdelset(&sighold, SIGKILL);
if (!sigismember(&sigmask, SIGTERM))
sigdelset(&sighold, SIGTERM);
curthread->t_hold = sighold;
rlimit = rctl_enforced_value(rctlproc_legacy[RLIMIT_CORE], p->p_rctls,
p);
mutex_exit(&p->p_lock);
/*
* Undo any watchpoints.
*/
pr_free_watched_pages(p);
/*
* The presence of a current signal prevents file i/o
* from succeeding over a network. We copy the current
* signal information to the side and cancel the current
* signal so that the core dump will succeed.
*/
ASSERT(lwp->lwp_cursig == sig);
lwp->lwp_cursig = 0;
lwp->lwp_extsig = 0;
if (lwp->lwp_curinfo == NULL) {
bzero(&lwp->lwp_siginfo, sizeof (k_siginfo_t));
lwp->lwp_siginfo.si_signo = sig;
lwp->lwp_siginfo.si_code = SI_NOINFO;
} else {
bcopy(&lwp->lwp_curinfo->sq_info,
&lwp->lwp_siginfo, sizeof (k_siginfo_t));
siginfofree(lwp->lwp_curinfo);
lwp->lwp_curinfo = NULL;
}
/*
* Convert the core file name patterns into path names
* and call do_core() to write the core files.
*/
if (my_cg->core_options & CC_PROCESS_PATH) {
mutex_enter(&p->p_lock);
if (p->p_corefile != NULL)
rp = corectl_path_value(p->p_corefile);
else
rp = NULL;
mutex_exit(&p->p_lock);
if (rp != NULL) {
fp_process = kmem_alloc(MAXPATHLEN, KM_SLEEP);
error1 = expand_string(refstr_value(rp),
fp_process, MAXPATHLEN, p->p_cred);
if (error1 == 0)
error1 = do_core(fp_process, sig, CORE_PROC,
my_cg);
refstr_rele(rp);
}
}
if (my_cg->core_options & CC_GLOBAL_PATH)
error2 = dump_one_core(sig, rlimit, CORE_ZONE, my_cg,
&fp_global);
if (global_cg != my_cg && (global_cg->core_options & CC_GLOBAL_PATH))
error3 = dump_one_core(sig, rlimit, CORE_GLOBAL, global_cg,
&fp_zone);
/*
* Restore the signal hold mask.
*/
mutex_enter(&p->p_lock);
curthread->t_hold = sigmask;
mutex_exit(&p->p_lock);
if (!ext && p->p_ct_process != NULL)
contract_process_core(p->p_ct_process, p, sig,
error1 == 0 ? fp_process : NULL,
error2 == 0 ? fp_global : NULL,
error3 == 0 ? fp_zone : NULL);
if (fp_process != NULL)
kmem_free(fp_process, MAXPATHLEN);
if (fp_global != NULL)
kmem_free(fp_global, MAXPATHLEN);
if (fp_zone != NULL)
kmem_free(fp_zone, MAXPATHLEN);
/*
* Return non-zero if no core file was created.
*/
return (error1 != 0 && error2 != 0 && error3 != 0);
}
/*
* Maximum chunk size for dumping core files,
* size in pages, patchable in /etc/system
*/
uint_t core_chunk = 32;
/*
* The delay between core_write() calls, in microseconds. The default
* matches one "normal" clock tick, or 10 milliseconds.
*/
clock_t core_delay_usec = 10000;
/*
* Common code to core dump process memory. The core_seg routine does i/o
* using core_write() below, and so it has the same failure semantics.
*/
int
core_seg(proc_t *p, vnode_t *vp, offset_t offset, caddr_t addr, size_t size,
rlim64_t rlimit, cred_t *credp)
{
caddr_t eaddr;
caddr_t base;
size_t len;
int err = 0;
eaddr = addr + size;
for (base = addr; base < eaddr; base += len) {
len = eaddr - base;
if (as_memory(p->p_as, &base, &len) != 0)
return (0);
/*
* Reduce len to a reasonable value so that we don't
* overwhelm the VM system with a monstrously large
* single write and cause pageout to stop running.
*/
if (len > (size_t)core_chunk * PAGESIZE)
len = (size_t)core_chunk * PAGESIZE;
err = core_write(vp, UIO_USERSPACE,
offset + (size_t)(base - addr), base, len, rlimit, credp);
if (err == 0) {
/*
* Give pageout a chance to run.
* Also allow core dumping to be interruptible.
*/
err = delay_sig(drv_usectohz(core_delay_usec));
}
if (err)
return (err);
}
return (0);
}
/*
* Wrapper around vn_rdwr to perform writes to a core file. For core files,
* we always want to write as much as we possibly can, and then make sure to
* return either 0 to the caller (for success), or the actual errno value.
* By using this function, the caller can omit additional code for handling
* retries and errors for partial writes returned by vn_rdwr. If vn_rdwr
* unexpectedly returns zero but no progress has been made, we return ENOSPC.
*/
int
core_write(vnode_t *vp, enum uio_seg segflg, offset_t offset,
const void *buf, size_t len, rlim64_t rlimit, cred_t *credp)
{
ssize_t resid = len;
int error = 0;
while (len != 0) {
error = vn_rdwr(UIO_WRITE, vp, (caddr_t)buf, len, offset,
segflg, 0, rlimit, credp, &resid);
if (error != 0)
break;
if (resid >= len)
return (ENOSPC);
buf = (const char *)buf + len - resid;
offset += len - resid;
len = resid;
}
return (error);
}