10 files changed, 146 insertions, 18 deletions

diff --git a/include/unistd.h b/include/unistd.h
index 5a4991ef9fe1d..02df2515eaaa6 100644
--- a/include/unistd.h
+++ b/include/unistd.h
@@ -494,6 +494,7 @@ struct crypt_data {
 int	 acct(const char *);
 int	 async_daemon(void);
 int	 check_utility_compat(const char *);
+int	 close_range(unsigned int, unsigned int, int);
 ssize_t	 copy_file_range(int, off_t *, int, off_t *, size_t, unsigned int);
 const char *
 	 crypt_get_format(void);
diff --git a/lib/libc/sys/Makefile.inc b/lib/libc/sys/Makefile.inc
index cc882e21a607a..913fe56eefbec 100644
--- a/lib/libc/sys/Makefile.inc
+++ b/lib/libc/sys/Makefile.inc
@@ -371,6 +371,7 @@ MLINKS+=chown.2 fchown.2 \
 	chown.2 lchown.2
 MLINKS+=clock_gettime.2 clock_getres.2 \
 	clock_gettime.2 clock_settime.2
+MLINKS+=closefrom.2 close_range.2
 MLINKS+=nanosleep.2 clock_nanosleep.2
 MLINKS+=cpuset.2 cpuset_getid.2 \
 	cpuset.2 cpuset_setid.2
diff --git a/lib/libc/sys/Symbol.map b/lib/libc/sys/Symbol.map
index aa60da2a67899..4d3bd5115af3a 100644
--- a/lib/libc/sys/Symbol.map
+++ b/lib/libc/sys/Symbol.map
@@ -403,6 +403,7 @@ FBSD_1.5 {
 
 FBSD_1.6 {
 	__sysctlbyname;
+	close_range;
 	copy_file_range;
 	fhlink;
 	fhlinkat;
diff --git a/lib/libc/sys/closefrom.2 b/lib/libc/sys/closefrom.2
index a0b5fc218666c..db41c617dc7f4 100644
--- a/lib/libc/sys/closefrom.2
+++ b/lib/libc/sys/closefrom.2
@@ -25,11 +25,12 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd June 12, 2009
+.Dd April 12, 2020
 .Dt CLOSEFROM 2
 .Os
 .Sh NAME
-.Nm closefrom
+.Nm closefrom ,
+.Nm close_range
 .Nd delete open file descriptors
 .Sh LIBRARY
 .Lb libc
@@ -37,6 +38,8 @@
 .In unistd.h
 .Ft void
 .Fn closefrom "int lowfd"
+.Ft int
+.Fn close_range "u_int lowfd" "u_int highfd" "int flags"
 .Sh DESCRIPTION
 The
 .Fn closefrom
@@ -44,6 +47,40 @@ system call deletes all open file descriptors greater than or equal to
 .Fa lowfd
 from the per-process object reference table.
 Any errors encountered while closing file descriptors are ignored.
+.Pp
+The
+.Fn close_range
+system call deletes all open file descriptors between
+.Fa lowfd
+and
+.Fa highfd
+inclusive, clamped to the range of open file descriptors.
+Any errors encountered while closing file descriptors are ignored.
+There are currently no defined
+.Fa flags .
+.Sh RETURN VALUES
+Upon successful completion,
+.Fn close_range
+returns a value
+of 0.
+Otherwise, a value of -1 is returned and the global variable
+.Va errno
+is set to indicate the error.
+.Sh ERRORS
+The
+.Fn close_range
+system call
+will fail if:
+.Bl -tag -width Er
+.It Bq Er EINVAL
+The
+.Fa highfd
+argument is lower than the
+.Fa lowfd
+argument.
+.It Bq Er EINVAL
+An invalid flag was set.
+.El
 .Sh SEE ALSO
 .Xr close 2
 .Sh HISTORY
diff --git a/sys/compat/freebsd32/syscalls.master b/sys/compat/freebsd32/syscalls.master
index 049e0b78500c2..0f735faca8e11 100644
--- a/sys/compat/freebsd32/syscalls.master
+++ b/sys/compat/freebsd32/syscalls.master
@@ -1162,5 +1162,7 @@
 573	AUE_NULL	NOPROTO	{ int sigfastblock(int cmd, uint32_t *ptr); }
 574	AUE_REALPATHAT	NOPROTO { int __realpathat(int fd, const char *path, \
 				    char *buf, size_t size, int flags); }
+575	AUE_NULL	NOPROTO	{ int close_range(u_int lowfd, u_int highfd, \
+				    int flags); }
 
 ; vim: syntax=off
diff --git a/sys/kern/capabilities.conf b/sys/kern/capabilities.conf
index 555a0232bde38..c465eca0bc6d9 100644
--- a/sys/kern/capabilities.conf
+++ b/sys/kern/capabilities.conf
@@ -131,6 +131,7 @@ clock_gettime
 ## Always allow file descriptor close(2).
 ##
 close
+close_range
 closefrom
 
 ##
diff --git a/sys/kern/kern_descrip.c b/sys/kern/kern_descrip.c
index 5357189936311..580956c5a0e31 100644
--- a/sys/kern/kern_descrip.c
+++ b/sys/kern/kern_descrip.c
@@ -1313,6 +1313,57 @@ kern_close(struct thread *td, int fd)
 	return (closefp(fdp, fd, fp, td, 1));
 }
 
+int
+kern_close_range(struct thread *td, u_int lowfd, u_int highfd)
+{
+	struct filedesc *fdp;
+	int fd, ret;
+
+	ret = 0;
+	fdp = td->td_proc->p_fd;
+	FILEDESC_SLOCK(fdp);
+
+	/*
+	 * Check this prior to clamping; closefrom(3) with only fd 0, 1, and 2
+	 * open should not be a usage error.  From a close_range() perspective,
+	 * close_range(3, ~0U, 0) in the same scenario should also likely not
+	 * be a usage error as all fd above 3 are in-fact already closed.
+	 */
+	if (highfd < lowfd) {
+		ret = EINVAL;
+		goto out;
+	}
+	/* Clamped to [lowfd, fd_lastfile] */
+	highfd = MIN(highfd, fdp->fd_lastfile);
+	for (fd = lowfd; fd <= highfd; fd++) {
+		if (fdp->fd_ofiles[fd].fde_file != NULL) {
+			FILEDESC_SUNLOCK(fdp);
+			(void)kern_close(td, fd);
+			FILEDESC_SLOCK(fdp);
+		}
+	}
+out:
+	FILEDESC_SUNLOCK(fdp);
+	return (ret);
+}
+
+#ifndef _SYS_SYSPROTO_H_
+struct close_range_args {
+	u_int	lowfd;
+	u_int	highfd;
+	int	flags;
+};
+#endif
+int
+sys_close_range(struct thread *td, struct close_range_args *uap)
+{
+
+	/* No flags currently defined */
+	if (uap->flags != 0)
+		return (EINVAL);
+	return (kern_close_range(td, uap->lowfd, uap->highfd));
+}
+
 /*
  * Close open file descriptors.
  */
@@ -1325,28 +1376,16 @@ struct closefrom_args {
 int
 sys_closefrom(struct thread *td, struct closefrom_args *uap)
 {
-	struct filedesc *fdp;
-	int fd;
+	u_int lowfd;
 
-	fdp = td->td_proc->p_fd;
 	AUDIT_ARG_FD(uap->lowfd);
 
 	/*
 	 * Treat negative starting file descriptor values identical to
 	 * closefrom(0) which closes all files.
 	 */
-	if (uap->lowfd < 0)
-		uap->lowfd = 0;
-	FILEDESC_SLOCK(fdp);
-	for (fd = uap->lowfd; fd <= fdp->fd_lastfile; fd++) {
-		if (fdp->fd_ofiles[fd].fde_file != NULL) {
-			FILEDESC_SUNLOCK(fdp);
-			(void)kern_close(td, fd);
-			FILEDESC_SLOCK(fdp);
-		}
-	}
-	FILEDESC_SUNLOCK(fdp);
-	return (0);
+	lowfd = MAX(0, uap->lowfd);
+	return (kern_close_range(td, lowfd, ~0U));
 }
 
 #if defined(COMPAT_43)
diff --git a/sys/kern/syscalls.master b/sys/kern/syscalls.master
index 8a61610daf067..ec8e03b65ee98 100644
--- a/sys/kern/syscalls.master
+++ b/sys/kern/syscalls.master
@@ -3227,6 +3227,13 @@
 		    int flags
 		);
 	}
+575	AUE_NULL	STD {
+		int close_range(
+		    u_int lowfd,
+		    u_int highfd,
+		    int flags
+		);
+	}
 
 ; Please copy any additions and changes to the following compatability tables:
 ; sys/compat/freebsd32/syscalls.master
diff --git a/sys/sys/syscallsubr.h b/sys/sys/syscallsubr.h
index 5a7f2169e74d1..1593ef2c49415 100644
--- a/sys/sys/syscallsubr.h
+++ b/sys/sys/syscallsubr.h
@@ -105,6 +105,7 @@ int	kern_clock_settime(struct thread *td, clockid_t clock_id,
 	    struct timespec *ats);
 void	kern_thread_cputime(struct thread *targettd, struct timespec *ats);
 void	kern_process_cputime(struct proc *targetp, struct timespec *ats);
+int	kern_close_range(struct thread *td, u_int lowfd, u_int highfd);
 int	kern_close(struct thread *td, int fd);
 int	kern_connectat(struct thread *td, int dirfd, int fd,
 	    struct sockaddr *sa);
diff --git a/tests/sys/file/closefrom_test.c b/tests/sys/file/closefrom_test.c
index 78cfeecae0261..7ce93415519e7 100644
--- a/tests/sys/file/closefrom_test.c
+++ b/tests/sys/file/closefrom_test.c
@@ -146,7 +146,7 @@ main(void)
 	pid_t pid;
 	int fd, i, start;
 
-	printf("1..15\n");
+	printf("1..19\n");
 
 	/* We better start up with fd's 0, 1, and 2 open. */
 	start = devnull();
@@ -271,5 +271,43 @@ main(void)
 		fail("closefrom", "highest fd %d", fd);
 	ok("closefrom");
 
+	/* Chew up another 8 fd */
+	for (i = 0; i < 8; i++)
+		(void)devnull();
+	fd = highest_fd();
+	start = fd - 7;
+
+	/* close_range() a hole in the middle */
+	close_range(start + 3, start + 5, 0);
+	for (i = start + 3; i < start + 6; ++i) {
+		if (close(i) == 0 || errno != EBADF) {
+			--i;
+			break;
+		}
+	}
+	if (i != start + 6)
+		fail("close_range", "failed to close at %d in %d - %d", i + 1,
+		    start + 3, start + 6);
+	ok("close_range");
+
+	/* close_range from the middle of the hole */
+	close_range(start + 4, start + 6, 0);
+	if ((i = highest_fd()) != fd)
+		fail("close_range", "highest fd %d", i);
+	ok("close_range");
+
+	/* close_range to the end; effectively closefrom(2) */
+	close_range(start + 3, ~0L, 0);
+	if ((i = highest_fd()) != start + 2)
+		fail("close_range", "highest fd %d", i);
+	ok("close_range");
+
+	/* Now close the rest */
+	close_range(start, start + 4, 0);
+	fd = highest_fd();
+	if (fd != 3)
+		fail("close_range", "highest fd %d", fd);
+	ok("close_range");
+
 	return (0);
 }