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Code Issues Releases Activity

For some reason when I started to pass filedescent structures instead of

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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 <jbeich@tormail.org>
Simple testcase provided by:	mjg
This commit is contained in:
Pawel Jakub Dawidek 2013-03-03 23:39:30 +00:00
parent 5f39e56581
commit 8cb539f18f
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=247740
1 changed files with 28 additions and 20 deletions
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48
sys/kern/uipc_usrreq.c
View File

@ -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, struct mbuf **controlp)
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, struct mbuf **controlp)
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 thread *td)
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, struct thread *td)
* 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, struct thread *td)
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)(struct file *))
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) {