Author: pjd
Date: Sun Mar 3 23:39:30 2013
New Revision: 247740
URL: http://svnweb.freebsd.org/changeset/base/247740
Log:
For some reason when I started to pass filedescent structures instead of
pointers to the file structure receiving descriptors stopped to work when also
at least few kilobytes of data is being send. In the kernel the
soreceive_generic() function doesn't see control mbuf as the first mbuf and
unp_externalize() is never called, first 6(?) kilobytes of data is missing as
well on receiving end.
This breaks for example tmux.
I don't know yet why going from 8 bytes to sizeof(struct filedescent) per
descriptor (or even to 16 bytes per descriptor) breaks things, but to
work-around it for now use 8 bytes per file descriptor at the cost of memory
allocation.
Reported by: flo, Diane Bruce, Jan Beich <jbe...@tormail.org>
Simple testcase provided by: mjg
Modified:
head/sys/kern/uipc_usrreq.c
Modified: head/sys/kern/uipc_usrreq.c
==============================================================================
--- head/sys/kern/uipc_usrreq.c Sun Mar 3 23:27:21 2013 (r247739)
+++ head/sys/kern/uipc_usrreq.c Sun Mar 3 23:39:30 2013 (r247740)
@@ -102,6 +102,8 @@ __FBSDID("$FreeBSD$");
#include <vm/uma.h>
+MALLOC_DECLARE(M_FILECAPS);
+
/*
* Locking key:
* (l) Locked using list lock
@@ -282,7 +284,7 @@ static void unp_drop(struct unpcb *, int
static void unp_gc(__unused void *, int);
static void unp_scan(struct mbuf *, void (*)(struct file *));
static void unp_discard(struct file *);
-static void unp_freerights(struct filedescent *, int);
+static void unp_freerights(struct filedescent **, int);
static void unp_init(void);
static int unp_internalize(struct mbuf **, struct thread *);
static void unp_internalize_fp(struct file *);
@@ -1679,17 +1681,17 @@ unp_drop(struct unpcb *unp, int errno)
}
static void
-unp_freerights(struct filedescent *fde, int fdcount)
+unp_freerights(struct filedescent **fdep, int fdcount)
{
struct file *fp;
int i;
- for (i = 0; i < fdcount; i++, fde++) {
- fp = fde->fde_file;
- filecaps_free(&fdep->fde_caps);
- bzero(fde, sizeof(*fde));
+ for (i = 0; i < fdcount; i++) {
+ fp = fdep[i]->fde_file;
+ filecaps_free(&fdep[i]->fde_caps);
unp_discard(fp);
}
+ free(fdep[0], M_FILECAPS);
}
static int
@@ -1700,7 +1702,7 @@ unp_externalize(struct mbuf *control, st
int i;
int *fdp;
struct filedesc *fdesc = td->td_proc->p_fd;
- struct filedescent *fde, *fdep;
+ struct filedescent *fde, **fdep;
void *data;
socklen_t clen = control->m_len, datalen;
int error, newfds;
@@ -1756,16 +1758,18 @@ unp_externalize(struct mbuf *control, st
fdp = (int *)
CMSG_DATA(mtod(*controlp, struct cmsghdr *));
- for (i = 0; i < newfds; i++, fdep++, fdp++) {
+ for (i = 0; i < newfds; i++, fdp++) {
if (fdalloc(td, 0, &f))
panic("unp_externalize fdalloc failed");
fde = &fdesc->fd_ofiles[f];
- fde->fde_file = fdep->fde_file;
- filecaps_move(&fdep->fde_caps, &fde->fde_caps);
+ fde->fde_file = fdep[0]->fde_file;
+ filecaps_move(&fdep[0]->fde_caps,
+ &fde->fde_caps);
unp_externalize_fp(fde->fde_file);
*fdp = f;
}
FILEDESC_XUNLOCK(fdesc);
+ free(fdep[0], M_FILECAPS);
} else {
/* We can just copy anything else across. */
if (error || controlp == NULL)
@@ -1840,7 +1844,7 @@ unp_internalize(struct mbuf **controlp,
struct bintime *bt;
struct cmsghdr *cm = mtod(control, struct cmsghdr *);
struct cmsgcred *cmcred;
- struct filedescent *fde, *fdep;
+ struct filedescent *fde, **fdep, *fdev;
struct file *fp;
struct timeval *tv;
int i, fd, *fdp;
@@ -1914,7 +1918,7 @@ unp_internalize(struct mbuf **controlp,
* Now replace the integer FDs with pointers to the
* file structure and capability rights.
*/
- newlen = oldfds * sizeof(*fdep);
+ newlen = oldfds * sizeof(fdep[0]);
*controlp = sbcreatecontrol(NULL, newlen,
SCM_RIGHTS, SOL_SOCKET);
if (*controlp == NULL) {
@@ -1923,13 +1927,17 @@ unp_internalize(struct mbuf **controlp,
goto out;
}
fdp = data;
- fdep = (struct filedescent *)
+ fdep = (struct filedescent **)
CMSG_DATA(mtod(*controlp, struct cmsghdr *));
- for (i = 0; i < oldfds; i++, fdep++, fdp++) {
+ fdev = malloc(sizeof(*fdev) * oldfds, M_FILECAPS,
+ M_WAITOK);
+ for (i = 0; i < oldfds; i++, fdev++, fdp++) {
fde = &fdesc->fd_ofiles[*fdp];
- fdep->fde_file = fde->fde_file;
- filecaps_copy(&fde->fde_caps, &fdep->fde_caps);
- unp_internalize_fp(fdep->fde_file);
+ fdep[i] = fdev;
+ fdep[i]->fde_file = fde->fde_file;
+ filecaps_copy(&fde->fde_caps,
+ &fdep[i]->fde_caps);
+ unp_internalize_fp(fdep[i]->fde_file);
}
FILEDESC_SUNLOCK(fdesc);
break;
@@ -2291,7 +2299,7 @@ static void
unp_scan(struct mbuf *m0, void (*op)(struct file *))
{
struct mbuf *m;
- struct filedescent *fdep;
+ struct filedescent **fdep;
struct cmsghdr *cm;
void *data;
int i;
@@ -2318,8 +2326,8 @@ unp_scan(struct mbuf *m0, void (*op)(str
cm->cmsg_type == SCM_RIGHTS) {
qfds = datalen / sizeof(*fdep);
fdep = data;
- for (i = 0; i < qfds; i++, fdep++)
- (*op)(fdep->fde_file);
+ for (i = 0; i < qfds; i++)
+ (*op)(fdep[i]->fde_file);
}
if (CMSG_SPACE(datalen) < clen) {
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