Date: Sun, 12 Apr 2020 21:23:20 +0000 (UTC) From: Kyle Evans <kevans@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r359836 - in head: include lib/libc/sys sys/compat/freebsd32 sys/kern sys/sys tests/sys/file Message-ID: <202004122123.03CLNK82073001@repo.freebsd.org>
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Author: kevans Date: Sun Apr 12 21:23:19 2020 New Revision: 359836 URL: https://svnweb.freebsd.org/changeset/base/359836 Log: Implement a close_range(2) syscall close_range(min, max, flags) allows for a range of descriptors to be closed. The Python folk have indicated that they would much prefer this interface to closefrom(2), as the case may be that they/someone have special fds dup'd to higher in the range and they can't necessarily closefrom(min) because they don't want to hit the upper range, but relocating them to lower isn't necessarily feasible. sys_closefrom has been rewritten to use kern_close_range() using ~0U to indicate closing to the end of the range. This was chosen rather than requiring callers of kern_close_range() to hold FILEDESC_SLOCK across the call to kern_close_range for simplicity. The flags argument of close_range(2) is currently unused, so any flags set is currently EINVAL. It was added to the interface in Linux so that future flags could be added for, e.g., "halt on first error" and things of this nature. This patch is based on a syscall of the same design that is expected to be merged into Linux. Reviewed by: kib, markj, vangyzen (all slightly earlier revisions) Differential Revision: https://reviews.freebsd.org/D21627 Modified: head/include/unistd.h head/lib/libc/sys/Makefile.inc head/lib/libc/sys/Symbol.map head/lib/libc/sys/closefrom.2 head/sys/compat/freebsd32/syscalls.master head/sys/kern/capabilities.conf head/sys/kern/kern_descrip.c head/sys/kern/syscalls.master head/sys/sys/syscallsubr.h head/tests/sys/file/closefrom_test.c Modified: head/include/unistd.h ============================================================================== --- head/include/unistd.h Sun Apr 12 20:54:35 2020 (r359835) +++ head/include/unistd.h Sun Apr 12 21:23:19 2020 (r359836) @@ -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); Modified: head/lib/libc/sys/Makefile.inc ============================================================================== --- head/lib/libc/sys/Makefile.inc Sun Apr 12 20:54:35 2020 (r359835) +++ head/lib/libc/sys/Makefile.inc Sun Apr 12 21:23:19 2020 (r359836) @@ -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 Modified: head/lib/libc/sys/Symbol.map ============================================================================== --- head/lib/libc/sys/Symbol.map Sun Apr 12 20:54:35 2020 (r359835) +++ head/lib/libc/sys/Symbol.map Sun Apr 12 21:23:19 2020 (r359836) @@ -403,6 +403,7 @@ FBSD_1.5 { FBSD_1.6 { __sysctlbyname; + close_range; copy_file_range; fhlink; fhlinkat; Modified: head/lib/libc/sys/closefrom.2 ============================================================================== --- head/lib/libc/sys/closefrom.2 Sun Apr 12 20:54:35 2020 (r359835) +++ head/lib/libc/sys/closefrom.2 Sun Apr 12 21:23:19 2020 (r359836) @@ -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 .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 Modified: head/sys/compat/freebsd32/syscalls.master ============================================================================== --- head/sys/compat/freebsd32/syscalls.master Sun Apr 12 20:54:35 2020 (r359835) +++ head/sys/compat/freebsd32/syscalls.master Sun Apr 12 21:23:19 2020 (r359836) @@ -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 Modified: head/sys/kern/capabilities.conf ============================================================================== --- head/sys/kern/capabilities.conf Sun Apr 12 20:54:35 2020 (r359835) +++ head/sys/kern/capabilities.conf Sun Apr 12 21:23:19 2020 (r359836) @@ -131,6 +131,7 @@ clock_gettime ## Always allow file descriptor close(2). ## close +close_range closefrom ## Modified: head/sys/kern/kern_descrip.c ============================================================================== --- head/sys/kern/kern_descrip.c Sun Apr 12 20:54:35 2020 (r359835) +++ head/sys/kern/kern_descrip.c Sun Apr 12 21:23:19 2020 (r359836) @@ -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) Modified: head/sys/kern/syscalls.master ============================================================================== --- head/sys/kern/syscalls.master Sun Apr 12 20:54:35 2020 (r359835) +++ head/sys/kern/syscalls.master Sun Apr 12 21:23:19 2020 (r359836) @@ -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 Modified: head/sys/sys/syscallsubr.h ============================================================================== --- head/sys/sys/syscallsubr.h Sun Apr 12 20:54:35 2020 (r359835) +++ head/sys/sys/syscallsubr.h Sun Apr 12 21:23:19 2020 (r359836) @@ -105,6 +105,7 @@ int kern_clock_settime(struct thread *td, clockid_t cl 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); Modified: head/tests/sys/file/closefrom_test.c ============================================================================== --- head/tests/sys/file/closefrom_test.c Sun Apr 12 20:54:35 2020 (r359835) +++ head/tests/sys/file/closefrom_test.c Sun Apr 12 21:23:19 2020 (r359836) @@ -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(); @@ -270,6 +270,44 @@ main(void) if (fd != 3) 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); }
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