>Synopsis: mg editor: endless loop using replace-regexp
>Category: system
>Environment:
System : OpenBSD 7.4
Details : OpenBSD 7.4 (GENERIC.MP) #2: Fri Dec 8 15:39:04 MST 2023
[email protected]:/usr/src/sys/arch/amd64/compile/GENERIC.MP
Architecture: OpenBSD.amd64
Machine : amd64
>Description:
The command 'regexp-replace "^.*$" ""' enters an endless loop (until
memory exhausted). This behaviour also applies to query-replace-regexp
with the "!" option.
This is due to a change I suggested to re_forwsrch, that is, not moving
dot when the line is empty (re_search.c 1.35). The reason for this
change was to ensure the replacement took effect on the starting line of
a replace-regexp, even if the line was empty.
>How-To-Repeat:
As above.
>Fix:
Here's an alternative method for achieving this end, without the
unpleasant consquence. It's rather more intrusive than I'd like.
--- re_search_orig.c 2024-03-02 13:00:43.734949005 +0000
+++ re_search.c 2024-03-04 14:33:09.659288168 +0000
@@ -34,12 +34,15 @@
#define RE_NMATCH 10 /* max number of matches */
#define REPLEN 256 /* max length of replacement string */
+#define MOVEDOT 1 /* for use with re_forwsrch
*/
+#define NO_MOVEDOT 0
+
char re_pat[NPAT]; /* regex pattern */
int re_srch_lastdir = SRCH_NOPR; /* last search flags */
int casefoldsearch = TRUE; /* does search ignore case? */
static int re_doreplace(RSIZE, char *);
-static int re_forwsrch(void);
+static int re_forwsrch(int);
static int re_backsrch(void);
static int re_readpattern(char *);
static int killmatches(int);
@@ -58,7 +61,7 @@
if ((s = re_readpattern("RE Search")) != TRUE)
return (s);
- if (re_forwsrch() == FALSE) {
+ if (re_forwsrch(MOVEDOT) == FALSE) {
dobeep();
ewprintf("Search failed: \"%s\"", re_pat);
return (FALSE);
@@ -107,7 +110,7 @@
return (FALSE);
}
if (re_srch_lastdir == SRCH_FORW) {
- if (re_forwsrch() == FALSE) {
+ if (re_forwsrch(MOVEDOT) == FALSE) {
dobeep();
ewprintf("Search failed: \"%s\"", re_pat);
return (FALSE);
@@ -138,6 +141,8 @@
int rcnt = 0; /* replacements made so far */
int plen, s; /* length of found string */
char news[NPAT]; /* replacement string */
+ int movedot = NO_MOVEDOT; /* no dot move on first call to */
+ /* forwsrch */
if ((s = re_readpattern("RE Query replace")) != TRUE)
return (s);
@@ -151,7 +156,8 @@
* or not. The "!" case makes the check always true, so it gets put
* into a tighter loop for efficiency.
*/
- while (re_forwsrch() == TRUE) {
+ while (re_forwsrch(movedot) == TRUE) {
+ movedot = MOVEDOT;
retry:
update(CMODE);
switch (getkey(FALSE)) {
@@ -181,7 +187,7 @@
if (re_doreplace((RSIZE)plen, news) == FALSE)
return (FALSE);
rcnt++;
- } while (re_forwsrch() == TRUE);
+ } while (re_forwsrch(MOVEDOT) == TRUE);
goto stopsearch;
case CCHR('?'): /* To not replace */
@@ -220,7 +226,7 @@
EFNUL | EFNEW | EFCR, re_pat) == NULL)
return (ABORT);
- while (re_forwsrch() == TRUE) {
+ while (re_forwsrch(rcnt) == TRUE) {
plen = regex_match[0].rm_eo - regex_match[0].rm_so;
if (re_doreplace((RSIZE)plen, news) == FALSE)
return (FALSE);
@@ -327,10 +333,14 @@
* This routine does the real work of a forward search. The pattern is
* sitting in the external variable "pat". If found, dot is updated, the
* window system is notified of the change, and TRUE is returned. If the
- * string isn't found, FALSE is returned.
+ * string isn't found, FALSE is returned.
+ *
+ * If movedot is non-zero, dot at end of line is shifted to next line.
+ * If zero, dot is left unchanged, which allows matching anchors in
+ * an empty starting line.
*/
static int
-re_forwsrch(void)
+re_forwsrch(int movedot)
{
int re_flags, tbo, tdotline, error;
struct line *clp;
@@ -339,13 +349,12 @@
tbo = curwp->w_doto;
tdotline = curwp->w_dotline;
- if (tbo == clp->l_used)
+ if (tbo == clp->l_used && movedot)
/*
- * Don't start matching past end of line -- must move to
- * beginning of next line, unless line is empty or at
- * end of file.
+ * Don't start matching past end of line if movedot is true
+ * - must move to beginning of next line, unless at end of file.
*/
- if (clp != curbp->b_headp && llength(clp) != 0) {
+ if (clp != curbp->b_headp) {
clp = lforw(clp);
tdotline++;
tbo = 0;
dmesg:
OpenBSD 7.4 (GENERIC.MP) #2: Fri Dec 8 15:39:04 MST 2023
[email protected]:/usr/src/sys/arch/amd64/compile/GENERIC.MP
real mem = 8523141120 (8128MB)
avail mem = 8245096448 (7863MB)
random: good seed from bootblocks
mpath0 at root
scsibus0 at mpath0: 256 targets
mainbus0 at root
bios0 at mainbus0: SMBIOS rev. 2.4 @ 0xf6540 (57 entries)
bios0: vendor Dell Inc. version "A19" date 12/21/2009
bios0: Dell Inc. Latitude E6500
acpi0 at bios0: ACPI 4.0
acpi0: sleep states S0 S3 S4 S5
acpi0: tables DSDT FACP HPET DMAR APIC ASF! MCFG TCPA SLIC SSDT
acpi0: wakeup devices PCI0(S4) PCIE(S4) USB1(S0) USB2(S0) USB3(S0) USB4(S0)
USB5(S0) USB6(S0) EHC2(S0) EHCI(S0) AZAL(S3) RP01(S4) RP02(S4) RP03(S4)
RP04(S3) RP05(S3) [...]
acpitimer0 at acpi0: 3579545 Hz, 24 bits
acpihpet0 at acpi0: 14318179 Hz
acpimadt0 at acpi0 addr 0xfee00000: PC-AT compat
cpu0 at mainbus0: apid 0 (boot processor)
cpu0: Intel(R) Core(TM)2 Duo CPU P8800 @ 2.66GHz, 2660.05 MHz, 06-17-0a, patch
00000a0b
cpu0:
FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,CFLUSH,DS,ACPI,MMX,FXSR,SSE,SSE2,SS,HTT,TM,PBE,SSE3,DTES64,MWAIT,DS-CPL,VMX,SMX,EST,TM2,SSSE3,CX16,xTPR,PDCM,SSE4.1,XSAVE,NXE,LONG,LAHF,PERF,SENSOR,MELTDOWN
cpu0: 32KB 64b/line 8-way D-cache, 32KB 64b/line 8-way I-cache, 3MB 64b/line
12-way L2 cache
cpu0: smt 0, core 0, package 0
mtrr: Pentium Pro MTRR support, 7 var ranges, 88 fixed ranges
cpu0: apic clock running at 266MHz
cpu0: mwait min=64, max=64, C-substates=0.2.2.2.2.1.3, IBE
cpu1 at mainbus0: apid 1 (application processor)
cpu1: Intel(R) Core(TM)2 Duo CPU P8800 @ 2.66GHz, 2660.05 MHz, 06-17-0a, patch
00000a0b
cpu1:
FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,CFLUSH,DS,ACPI,MMX,FXSR,SSE,SSE2,SS,HTT,TM,PBE,SSE3,DTES64,MWAIT,DS-CPL,VMX,SMX,EST,TM2,SSSE3,CX16,xTPR,PDCM,SSE4.1,XSAVE,NXE,LONG,LAHF,PERF,SENSOR,MELTDOWN
cpu1: 32KB 64b/line 8-way D-cache, 32KB 64b/line 8-way I-cache, 3MB 64b/line
12-way L2 cache
cpu1: smt 0, core 1, package 0
ioapic0 at mainbus0: apid 2 pa 0xfec00000, version 20, 24 pins, remapped
acpimcfg0 at acpi0
acpimcfg0: addr 0xf8000000, bus 0-63
acpimcfg0: addr 0x0, bus 0-0
acpiprt0 at acpi0: bus 0 (PCI0)
acpiprt1 at acpi0: bus 3 (PCIE)
acpiprt2 at acpi0: bus -1 (AGP_)
acpiprt3 at acpi0: bus 11 (RP01)
acpiprt4 at acpi0: bus 12 (RP02)
acpiprt5 at acpi0: bus 13 (RP03)
acpiprt6 at acpi0: bus 14 (RP04)
acpiprt7 at acpi0: bus -1 (RP05)
acpiprt8 at acpi0: bus -1 (RP06)
acpiec0 at acpi0
acpipci0 at acpi0 PCI0
acpicmos0 at acpi0
acpibtn0 at acpi0: LID_(wakeup)
acpibtn1 at acpi0: PBTN(wakeup)
acpibtn2 at acpi0: SBTN
acpiac0 at acpi0: AC unit online
acpibat0 at acpi0: BAT0 model "DELL C207203" serial 5003 type LION oem "Samsung
SDI"
acpibat1 at acpi0: BAT1 not present
"*pnp0c14" at acpi0 not configured
acpicpu0 at acpi0: !C3(100@162 mwait.3@0x50), !C2(500@1 mwait.1@0x10),
C1(1000@1 mwait.1), PSS
acpicpu1 at acpi0: !C3(100@162 mwait.3@0x50), !C2(500@1 mwait.1@0x10),
C1(1000@1 mwait.1), PSS
acpitz0 at acpi0: critical temperature is 107 degC
acpivideo0 at acpi0: VID_
acpivideo1 at acpi0: VID_
acpivout0 at acpivideo1: LCD_
acpivideo2 at acpi0: VID2
cpu0: Enhanced SpeedStep 2660 MHz: speeds: 2668, 2667, 2134, 1600, 800 MHz
pci0 at mainbus0 bus 0
pchb0 at pci0 dev 0 function 0 "Intel GM45 Host" rev 0x07
inteldrm0 at pci0 dev 2 function 0 "Intel GM45 Video" rev 0x07
drm0 at inteldrm0
intagp0 at inteldrm0
agp0 at intagp0: aperture at 0xe0000000, size 0x10000000
inteldrm0: apic 2 int 16, GM45, gen 4
"Intel GM45 Video" rev 0x07 at pci0 dev 2 function 1 not configured
em0 at pci0 dev 25 function 0 "Intel ICH9 IGP M AMT" rev 0x03: msi, address
00:26:b9:bf:2e:70
uhci0 at pci0 dev 26 function 0 "Intel 82801I USB" rev 0x03: apic 2 int 20
uhci1 at pci0 dev 26 function 1 "Intel 82801I USB" rev 0x03: apic 2 int 21
uhci2 at pci0 dev 26 function 2 "Intel 82801I USB" rev 0x03: apic 2 int 22
ehci0 at pci0 dev 26 function 7 "Intel 82801I USB" rev 0x03: apic 2 int 22
usb0 at ehci0: USB revision 2.0
uhub0 at usb0 configuration 1 interface 0 "Intel EHCI root hub" rev 2.00/1.00
addr 1
azalia0 at pci0 dev 27 function 0 "Intel 82801I HD Audio" rev 0x03: msi
azalia0: codecs: IDT 92HD71B7, Intel/0x2802, using IDT 92HD71B7
audio0 at azalia0
ppb0 at pci0 dev 28 function 0 "Intel 82801I PCIE" rev 0x03: msi
pci1 at ppb0 bus 11
ppb1 at pci0 dev 28 function 1 "Intel 82801I PCIE" rev 0x03: msi
pci2 at ppb1 bus 12
"Broadcom BCM4315" rev 0x01 at pci2 dev 0 function 0 not configured
ppb2 at pci0 dev 28 function 2 "Intel 82801I PCIE" rev 0x03: msi
pci3 at ppb2 bus 13
ppb3 at pci0 dev 28 function 3 "Intel 82801I PCIE" rev 0x03: msi
pci4 at ppb3 bus 14
uhci3 at pci0 dev 29 function 0 "Intel 82801I USB" rev 0x03: apic 2 int 20
uhci4 at pci0 dev 29 function 1 "Intel 82801I USB" rev 0x03: apic 2 int 21
uhci5 at pci0 dev 29 function 2 "Intel 82801I USB" rev 0x03: apic 2 int 22
ehci1 at pci0 dev 29 function 7 "Intel 82801I USB" rev 0x03: apic 2 int 20
usb1 at ehci1: USB revision 2.0
uhub1 at usb1 configuration 1 interface 0 "Intel EHCI root hub" rev 2.00/1.00
addr 1
ppb4 at pci0 dev 30 function 0 "Intel 82801BAM Hub-to-PCI" rev 0x93
pci5 at ppb4 bus 3
cbb0 at pci5 dev 1 function 0 "Ricoh 5C476 CardBus" rev 0xba: apic 2 int 19
"Ricoh 5C832 Firewire" rev 0x04 at pci5 dev 1 function 1 not configured
sdhc0 at pci5 dev 1 function 2 "Ricoh 5C822 SD/MMC" rev 0x21: apic 2 int 18
sdhc0: SDHC 1.00, 33 MHz base clock
sdmmc0 at sdhc0: 4-bit, sd high-speed, mmc high-speed
"Ricoh 5C843 MMC" rev 0x11 at pci5 dev 1 function 3 not configured
cardslot0 at cbb0 slot 0 flags 0
cardbus0 at cardslot0: bus 4 device 0 cacheline 0x10, lattimer 0x20
pcmcia0 at cardslot0
pcib0 at pci0 dev 31 function 0 "Intel 82801IEM LPC" rev 0x03
ahci0 at pci0 dev 31 function 2 "Intel 82801I AHCI" rev 0x03: msi, AHCI 1.2
ahci0: port 0: 3.0Gb/s
ahci0: port 1: 1.5Gb/s
scsibus1 at ahci0: 32 targets
sd0 at scsibus1 targ 0 lun 0: <ATA, KINGSTON SV300S3, 603A> naa.50026b775605cd58
sd0: 228936MB, 512 bytes/sector, 468862128 sectors, thin
cd0 at scsibus1 targ 1 lun 0: <TSSTcorp, DVD+-RW TS-U633F, D500> removable
ichiic0 at pci0 dev 31 function 3 "Intel 82801I SMBus" rev 0x03: apic 2 int 17
iic0 at ichiic0
spdmem0 at iic0 addr 0x50: 4GB DDR2 SDRAM non-parity PC2-6400CL6 SO-DIMM
spdmem1 at iic0 addr 0x52: 4GB DDR2 SDRAM non-parity PC2-6400CL6 SO-DIMM
usb2 at uhci0: USB revision 1.0
uhub2 at usb2 configuration 1 interface 0 "Intel UHCI root hub" rev 1.00/1.00
addr 1
usb3 at uhci1: USB revision 1.0
uhub3 at usb3 configuration 1 interface 0 "Intel UHCI root hub" rev 1.00/1.00
addr 1
usb4 at uhci2: USB revision 1.0
uhub4 at usb4 configuration 1 interface 0 "Intel UHCI root hub" rev 1.00/1.00
addr 1
usb5 at uhci3: USB revision 1.0
uhub5 at usb5 configuration 1 interface 0 "Intel UHCI root hub" rev 1.00/1.00
addr 1
usb6 at uhci4: USB revision 1.0
uhub6 at usb6 configuration 1 interface 0 "Intel UHCI root hub" rev 1.00/1.00
addr 1
usb7 at uhci5: USB revision 1.0
uhub7 at usb7 configuration 1 interface 0 "Intel UHCI root hub" rev 1.00/1.00
addr 1
isa0 at pcib0
isadma0 at isa0
pckbc0 at isa0 port 0x60/5 irq 1 irq 12
pckbd0 at pckbc0 (kbd slot)
wskbd0 at pckbd0: console keyboard
pms0 at pckbc0 (aux slot)
wsmouse0 at pms0 mux 0
pms0: ALPS Dualpoint, version 0x6222
wsmouse1 at pms0 mux 0
pcppi0 at isa0 port 0x61
spkr0 at pcppi0
vmm0 at mainbus0: unknown
ugen0 at uhub4 port 1 "Broadcom Corp 5880" rev 1.10/1.01 addr 2
uhidev0 at uhub6 port 2 configuration 1 interface 0 "vendor 0x13ba Barcode
Reader" rev 1.10/0.01 addr 2
uhidev0: iclass 3/1
ukbd0 at uhidev0: 8 variable keys, 6 key codes
wskbd1 at ukbd0 mux 1
uhidev1 at uhub6 port 2 configuration 1 interface 1 "vendor 0x13ba Barcode
Reader" rev 1.10/0.01 addr 2
uhidev1: iclass 3/1, 3 report ids
ums0 at uhidev1 reportid 1: 5 buttons, Z dir
wsmouse2 at ums0 mux 0
uhid0 at uhidev1 reportid 2: input=1, output=0, feature=0
ucc0 at uhidev1 reportid 3: 573 usages, 20 keys, array
wskbd2 at ucc0 mux 1
vscsi0 at root
scsibus2 at vscsi0: 256 targets
softraid0 at root
scsibus3 at softraid0: 256 targets
root on sd0a (660795fa2a3e9604.a) swap on sd0b dump on sd0b
inteldrm0: 1024x768, 32bpp
wsdisplay0 at inteldrm0 mux 1: console (std, vt100 emulation), using wskbd0
wskbd1: connecting to wsdisplay0
wskbd2: connecting to wsdisplay0
wsdisplay0: screen 1-5 added (std, vt100 emulation)
usbdevs:
Controller /dev/usb0:
addr 01: 8086:0000 Intel, EHCI root hub
high speed, self powered, config 1, rev 1.00
driver: uhub0
Controller /dev/usb1:
addr 01: 8086:0000 Intel, EHCI root hub
high speed, self powered, config 1, rev 1.00
driver: uhub1
Controller /dev/usb2:
addr 01: 8086:0000 Intel, UHCI root hub
full speed, self powered, config 1, rev 1.00
driver: uhub2
Controller /dev/usb3:
addr 01: 8086:0000 Intel, UHCI root hub
full speed, self powered, config 1, rev 1.00
driver: uhub3
Controller /dev/usb4:
addr 01: 8086:0000 Intel, UHCI root hub
full speed, self powered, config 1, rev 1.00
driver: uhub4
addr 02: 0a5c:5800 Broadcom Corp, 5880
full speed, power 100 mA, unconfigured, rev 1.01, iSerial
0123456789ABCD
driver: ugen0
Controller /dev/usb5:
addr 01: 8086:0000 Intel, UHCI root hub
full speed, self powered, config 1, rev 1.00
driver: uhub5
Controller /dev/usb6:
addr 01: 8086:0000 Intel, UHCI root hub
full speed, self powered, config 1, rev 1.00
driver: uhub6
addr 02: 13ba:0018 vendor 0x13ba, Barcode Reader
low speed, power 400 mA, config 1, rev 0.01
driver: uhidev0
driver: uhidev1
Controller /dev/usb7:
addr 01: 8086:0000 Intel, UHCI root hub
full speed, self powered, config 1, rev 1.00
driver: uhub7
