csplit(1) penultimate boundary bug (with patch from FreeBSD?)

[openbsd-26]

>Synopsis: csplit(1) penultimate boundary bug (with patch from FreeBSD?)
>Category: system
>Environment:
        System      : OpenBSD 6.8
        Details     : OpenBSD 6.8 (GENERIC) #5: Mon Feb 22 04:04:49 MST 2021
                         [hidden email]:/usr/src/sys/arch/amd64/compile/GENERIC

        Architecture: OpenBSD.amd64
        Machine     : amd64

(happens on all architectures I've tested on, including i386 and macppc,
not just amd64)

>Description:

csplit(1) adds an extra boundary marker on the penultimate file

>How-To-Repeat:

  $ printf 'boundary\n%i\n' $(jot 5) | csplit -k - /boundary/ '{999}'
  11
  11
  11
  11
  csplit: boundary: no match
  $ ls -lsF
  total 20
  4 -rw-r--r--  1 tim  tim  11 Apr  6 17:49 xx00
  4 -rw-r--r--  1 tim  tim  11 Apr  6 17:49 xx01
  4 -rw-r--r--  1 tim  tim  11 Apr  6 17:49 xx02
  4 -rw-r--r--  1 tim  tim  20 Apr  6 17:49 xx03
  4 -rw-r--r--  1 tim  tim  11 Apr  6 17:49 xx04
  $ cat xx02
  boundary
  3
  $ cat xx03
  boundary
  4
  boundary
  $
 
Note that the next-to-last file emits the matching boundary both at
the beginning and the end (the file also stands out as being 20 bytes
rather than 11 bytes) when it should only emit the first boundary.

>Fix:

It looks like this bug happened in FreeBSD's csplit(1) too

https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=163062

but has been fixed over on the FreeBSD side of things (diff available
at that URL) so you may be able to pull that in.



dmesg:
OpenBSD 6.8 (GENERIC) #5: Mon Feb 22 04:04:49 MST 2021
    [hidden email]:/usr/src/sys/arch/amd64/compile/GENERIC
real mem = 2080227328 (1983MB)
avail mem = 2002292736 (1909MB)
random: good seed from bootblocks
mpath0 at root
scsibus0 at mpath0: 256 targets
mainbus0 at root
bios0 at mainbus0: SMBIOS rev. 2.8 @ 0xf68b0 (9 entries)
bios0: vendor SeaBIOS version "2:1.10.2-58953eb7" date 04/01/2014
bios0: OpenStack Foundation OpenStack Nova
acpi0 at bios0: ACPI 1.0
acpi0: sleep states S3 S4 S5
acpi0: tables DSDT FACP APIC
acpi0: wakeup devices
acpitimer0 at acpi0: 3579545 Hz, 24 bits
acpimadt0 at acpi0 addr 0xfee00000: PC-AT compat
cpu0 at mainbus0: apid 0 (boot processor)
cpu0: Intel Core Processor (Haswell, no TSX, IBRS), 2394.83 MHz, 06-3c-01
cpu0: FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,CFLUSH,MMX,FXSR,SSE,SSE2,SSE3,PCLMUL,VMX,SSSE3,FMA3,CX16,PCID,SSE4.1,SSE4.2,x2APIC,MOVBE,POPCNT,DEADLINE,AES,XSAVE,AVX,F16C,RDRAND,HV,NXE,RDTSCP,LONG,LAHF,ABM,FSGSBASE,BMI1,AVX2,SMEP,BMI2,ERMS,INVPCID,MD_CLEAR,IBRS,IBPB,ARAT,XSAVEOPT,MELTDOWN
cpu0: 64KB 64b/line 2-way I-cache, 64KB 64b/line 2-way D-cache, 512KB 64b/line 16-way L2 cache
cpu0: ITLB 255 4KB entries direct-mapped, 255 4MB entries direct-mapped
cpu0: DTLB 255 4KB entries direct-mapped, 255 4MB entries direct-mapped
cpu0: smt 0, core 0, package 0
mtrr: Pentium Pro MTRR support, 8 var ranges, 88 fixed ranges
cpu0: apic clock running at 1000MHz
ioapic0 at mainbus0: apid 0 pa 0xfec00000, version 11, 24 pins
acpiprt0 at acpi0: bus 0 (PCI0)
"ACPI0006" at acpi0 not configured
acpipci0 at acpi0 PCI0
acpicmos0 at acpi0
"PNP0A06" at acpi0 not configured
"PNP0A06" at acpi0 not configured
"PNP0A06" at acpi0 not configured
"QEMU0002" at acpi0 not configured
"ACPI0010" at acpi0 not configured
acpicpu0 at acpi0: C1(@1 halt!)
cpu0: using VERW MDS workaround
pvbus0 at mainbus0: KVM
pvclock0 at pvbus0
pci0 at mainbus0 bus 0
pchb0 at pci0 dev 0 function 0 "Intel 82441FX" rev 0x02
pcib0 at pci0 dev 1 function 0 "Intel 82371SB ISA" rev 0x00
pciide0 at pci0 dev 1 function 1 "Intel 82371SB IDE" rev 0x00: DMA, channel 0 wired to compatibility, channel 1 wired to compatibility
pciide0: channel 0 disabled (no drives)
pciide0: channel 1 disabled (no drives)
uhci0 at pci0 dev 1 function 2 "Intel 82371SB USB" rev 0x01: apic 0 int 11
piixpm0 at pci0 dev 1 function 3 "Intel 82371AB Power" rev 0x03: apic 0 int 9
iic0 at piixpm0
vga1 at pci0 dev 2 function 0 "Cirrus Logic CL-GD5446" rev 0x00
wsdisplay0 at vga1 mux 1: console (80x25, vt100 emulation)
wsdisplay0: screen 1-5 added (80x25, vt100 emulation)
virtio0 at pci0 dev 3 function 0 "Qumranet Virtio Network" rev 0x00
vio0 at virtio0: address fa:16:3e:30:f3:22
virtio0: msix shared
virtio1 at pci0 dev 4 function 0 "Qumranet Virtio SCSI" rev 0x00
vioscsi0 at virtio1: qsize 128
scsibus1 at vioscsi0: 255 targets
sd0 at scsibus1 targ 0 lun 0: <QEMU, QEMU HARDDISK, 2.5+>
sd0: 20480MB, 512 bytes/sector, 41943040 sectors, thin
virtio1: msix shared
virtio2 at pci0 dev 5 function 0 "Qumranet Virtio Console" rev 0x00
virtio2: no matching child driver; not configured
virtio3 at pci0 dev 6 function 0 "Qumranet Virtio Memory Balloon" rev 0x00
viomb0 at virtio3
virtio3: apic 0 int 10
isa0 at pcib0
isadma0 at isa0
fdc0 at isa0 port 0x3f0/6 irq 6 drq 2
com0 at isa0 port 0x3f8/8 irq 4: ns16550a, 16 byte fifo
com1 at isa0 port 0x2f8/8 irq 3: ns16550a, 16 byte fifo
pckbc0 at isa0 port 0x60/5 irq 1 irq 12
pckbd0 at pckbc0 (kbd slot)
wskbd0 at pckbd0: console keyboard, using wsdisplay0
pms0 at pckbc0 (aux slot)
wsmouse0 at pms0 mux 0
pcppi0 at isa0 port 0x61
spkr0 at pcppi0
usb0 at uhci0: USB revision 1.0
uhub0 at usb0 configuration 1 interface 0 "Intel UHCI root hub" rev 1.00/1.00 addr 1
vmm0 at mainbus0: VMX/EPT (using slow L1TF mitigation)
uhidev0 at uhub0 port 1 configuration 1 interface 0 "QEMU QEMU USB Tablet" rev 2.00/0.00 addr 2
uhidev0: iclass 3/0
ums0 at uhidev0: 3 buttons, Z dir
wsmouse1 at ums0 mux 0
vscsi0 at root
scsibus2 at vscsi0: 256 targets
softraid0 at root
scsibus3 at softraid0: 256 targets
sd1 at scsibus3 targ 1 lun 0: <OPENBSD, SR CRYPTO, 006>
sd1: 20478MB, 512 bytes/sector, 41939696 sectors
root on sd1a (c1397fd0e257fe21.a) swap on sd1b dump on sd1b
fd0 at fdc0 drive 1: density unknown

usbdevs:
usbdevs: no USB controllers found