d/freebsd-nq
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Introduce a new F_DUP2FD command to fcntl(2), for compatibility with

Browse Source 
Solaris and AIX.
fcntl(fd, F_DUP2FD, arg) and dup2(fd, arg) are functionnaly equivalent.
Document it.
Add some regression tests (identical to the dup2(2) regression tests).

PR:		120233
Submitted by:	Jukka Ukkonen
Approved by:	rwaston (mentor)
MFC after:	1 month
This commit is contained in:
Antoine Brodin 2008-03-08 22:02:21 +00:00
parent 40f9a23605
commit e3ad7f6626
4 changed files with 115 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

38
lib/libc/sys/fcntl.2
View File

@ -28,7 +28,7 @@
.\" @(#)fcntl.2 8.2 (Berkeley) 1/12/94
.\" $FreeBSD$
.\"
.Dd January 12, 1994
.Dd March 8, 2008
.Dt FCNTL 2
.Os
.Sh NAME
@ -78,6 +78,18 @@ is set to remain open across
.Xr execve 2
system calls.
.El
.It Dv F_DUP2FD
It is functionally equivalent to
.Bd -literal -offset indent
dup2(fd, arg)
.Ed
.Pp
The
.Dv F_DUP2FD
constant is not portable, so it should not be used if portability is needed.
Use
.Fn dup2
instead.
.It Dv F_GETFD
Get the close-on-exec flag associated with the file descriptor
.Fa fd
@ -389,6 +401,9 @@ as follows:
.Bl -tag -width F_GETOWNX -offset indent
.It Dv F_DUPFD
A new file descriptor.
.It Dv F_DUP2FD
A file descriptor equal to
.Fa arg .
.It Dv F_GETFD
Value of flag (only the low-order bit is defined).
.It Dv F_GETFL
@ -432,6 +447,14 @@ is not a valid open file descriptor.
The argument
.Fa cmd
is
.Dv F_DUP2FD ,
and
.Fa arg
is not a valid file descriptor.
.Pp
The argument
.Fa cmd
is
.Dv F_SETLK
or
.Dv F_SETLKW ,
@ -495,6 +518,8 @@ The argument
.Fa cmd
is
.Dv F_DUPFD
or
.Dv F_DUP2FD
and the maximum number of file descriptors permitted for the
process are already in use,
or no file descriptors greater than or equal to
@ -567,6 +592,7 @@ for the reasons as stated in
.Xr tcgetpgrp 3 .
.Sh SEE ALSO
.Xr close 2 ,
.Xr dup2 2 ,
.Xr execve 2 ,
.Xr flock 2 ,
.Xr getdtablesize 2 ,
@ -575,8 +601,18 @@ for the reasons as stated in
.Xr lockf 3 ,
.Xr tcgetpgrp 3 ,
.Xr tcsetpgrp 3
.Sh STANDARDS
The
.Dv F_DUP2FD
constant is non portable.
It is provided for compatibility with AIX and Solaris.
.Sh HISTORY
The
.Fn fcntl
system call appeared in
.Bx 4.2 .
.Pp
The
.Dv F_DUP2FD
constant first appeared in
.Fx 7.1 .

7
sys/kern/kern_descrip.c
View File

@ -397,6 +397,11 @@ kern_fcntl(struct thread *td, int fd, int cmd, intptr_t arg)
error = do_dup(td, DUP_VARIABLE, fd, newmin, td->td_retval);
break;
case F_DUP2FD:
tmp = arg;
error = do_dup(td, DUP_FIXED, fd, tmp, td->td_retval);
break;
case F_GETFD:
FILEDESC_SLOCK(fdp);
if ((fp = fdtofp(fd, fdp)) == NULL) {
@ -633,7 +638,7 @@ kern_fcntl(struct thread *td, int fd, int cmd, intptr_t arg)
}
/*
* Common code for dup, dup2, and fcntl(F_DUPFD).
* Common code for dup, dup2, fcntl(F_DUPFD) and fcntl(F_DUP2FD).
*/
static int
do_dup(struct thread *td, enum dup_type type, int old, int new,

1
sys/sys/fcntl.h
View File

@ -181,6 +181,7 @@ typedef __pid_t pid_t;
#define F_GETLK 7 /* get record locking information */
#define F_SETLK 8 /* set record locking information */
#define F_SETLKW 9 /* F_SETLK; wait if blocked */
#define F_DUP2FD 10 /* duplicate file descriptor to arg */
/* file descriptor flags (F_GETFD, F_SETFD) */
#define FD_CLOEXEC 1 /* close-on-exec flag */

73
tools/regression/file/dup/dup.c
View File

@ -20,6 +20,15 @@
* Test #9: check if fcntl(F_DUPFD) cleared close-on-exec flag for duped fd.
* Test #10: check if dup2() to a fd > current maximum number of open files
* limit work.
* Test #11: check if fcntl(F_DUP2FD) works.
* Test #12: check if fcntl(F_DUP2FD) returned a fd we asked for.
* Test #13: check if fcntl(F_DUP2FD) cleared close-on-exec flag for duped fd.
* Test #14: check if fcntl(F_DUP2FD) allows to dup fd to itself.
* Test #15: check if fcntl(F_DUP2FD) returned a fd we asked for.
* Test #16: check if fcntl(F_DUP2FD) did not clear close-on-exec flag for
* duped fd.
* Test #17: check if fcntl(F_DUP2FD) to a fd > current maximum number of open
* files limit work.
*/
#include <sys/types.h>
@ -56,7 +65,7 @@ main(int __unused argc, char __unused *argv[])
orgfd = getafile();
printf("1..10\n");
printf("1..17\n");
/* If dup(2) ever work? */
if ((fd1 = dup(orgfd)) < 0)
@ -151,10 +160,70 @@ main(int __unused argc, char __unused *argv[])
++test;
if (getrlimit(RLIMIT_NOFILE, &rlp) < 0)
err(1, "getrlimit");
if ((fd2 = dup2(fd1, rlp.rlim_cur + 1)) == 0)
if ((fd2 = dup2(fd1, rlp.rlim_cur + 1)) >= 0)
printf("not ok %d - dup2(2) bypassed NOFILE limit\n", test);
else
printf("ok %d - dup2(2) didn't bypass NOFILE limit\n", test);
/* If fcntl(F_DUP2FD) ever work? */
if ((fd2 = fcntl(fd1, F_DUP2FD, fd1 + 1)) < 0)
err(1, "fcntl(F_DUP2FD)");
printf("ok %d - fcntl(F_DUP2FD) works\n", ++test);
/* Do we get the right fd? */
++test;
if (fd2 != fd1 + 1)
printf(
"no ok %d - fcntl(F_DUP2FD) didn't give us the right fd\n",
test);
else
printf("ok %d - fcntl(F_DUP2FD) returned a correct fd\n",
test);
/* Was close-on-exec cleared? */
++test;
if (fcntl(fd2, F_GETFD) != 0)
printf(
"not ok %d - fcntl(F_DUP2FD) didn't clear close-on-exec\n",
test);
else
printf("ok %d - fcntl(F_DUP2FD) cleared close-on-exec\n",
test);
/* Dup to itself */
if ((fd2 = fcntl(fd1, F_DUP2FD, fd1)) < 0)
err(1, "fcntl(F_DUP2FD)");
printf("ok %d - fcntl(F_DUP2FD) to itself works\n", ++test);
/* Do we get the right fd? */
++test;
if (fd2 != fd1)
printf(
"not ok %d - fcntl(F_DUP2FD) didn't give us the right fd\n",
test);
else
printf(
"ok %d - fcntl(F_DUP2FD) to itself returned a correct fd\n",
test);
/* Was close-on-exec cleared? */
++test;
if (fcntl(fd2, F_GETFD) == 0)
printf("not ok %d - fcntl(F_DUP2FD) cleared close-on-exec\n",
test);
else
printf("ok %d - fcntl(F_DUP2FD) didn't clear close-on-exec\n",
test);
++test;
if (getrlimit(RLIMIT_NOFILE, &rlp) < 0)
err(1, "getrlimit");
if ((fd2 = fcntl(fd1, F_DUP2FD, rlp.rlim_cur + 1)) >= 0)
printf("not ok %d - fcntl(F_DUP2FD) bypassed NOFILE limit\n",
test);
else
printf("ok %d - fcntl(F_DUP2FD) didn't bypass NOFILE limit\n",
test);
return (0);
}