>Number: 146916
>Category: bin
>Synopsis: [patch] sh(1) uses dumb terminal in single-user mode
>Confidential: no
>Severity: non-critical
>Priority: low
>Responsible: freebsd-bugs
>State: open
>Quarter:
>Keywords:
>Date-Required:
>Class: sw-bug
>Submitter-Id: current-users
>Arrival-Date: Mon May 24 11:50:01 UTC 2010
>Closed-Date:
>Last-Modified:
>Originator: Guy Yur
>Release: 8.0-RELEASE-p2
>Organization:
>Environment:
FreeBSD samwise.localdomain 8.0-RELEASE-p2 FreeBSD 8.0-RELEASE-p2 #0: Sat Mar
27 00:32:42 IDT 2010 r...@samwise.localdomain:/usr/obj/usr/src/sys/SAMWISE
i386
>Description:
1. sh doesn't call setenv() for "TERM" so getenv("TERM") will return NULL
in single-user mode when used as the first shell.
libedit el_init() passes "dumb" to ncurses if getenv("TERM") returns NULL.
"dumb" isn't in /usr/src/etc/termcap.small
2. sh doesn't call el_set(el, EL_TERMINAL, term) when TERM changes.
so libedit will keep thinking it has a "dumb" terminal.
3. rev 206182 changed 'bin/sh/options.c' to set -o emacs if interactive shell.
this is done before /.profile can set TERM= in single-user mode
so el_init() is called without TERM env var
>How-To-Repeat:
create /etc/termcap.small.db taken from /usr/src/etc/termcap.small
it should have cons25 (or xterm on CURRENT)
it should not have a "dumb" entry
in /.profile have
export TERM=${TERM:-cons25} # xterm on CURRENT
or any terminal found in /etc/termcap.small.db
boot into single-user mode and use the default /bin/sh
/usr shouldn't be not mounted
or have /usr/share/misc/termcap.db not accessible.
run `set -o emacs`
see
Cannot read termcap database;
using dumb terminal settings.
even though /etc/termcap.small.db is readable and cons25/xterm entry exists
>Fix:
looking in NetBSD, /bin/sh calls setenv/unsetenv for "TERM" before el_init()
and calls el_set(el, EL_TERMINAL, term) when TERM changes.
I have made patches using the changes against bin/sh in NetBSD.
Only the TERM support changes are included in the patches.
The patches are against head, svn revision 208452
cd /usr/src/bin/sh
patch < /patch/to/sh.patch
possible fixes to revision 206182 'bin/sh/options.c'
1. add the "dumb" entry to etc/termcap.small to silence el_init()
2. instead of enabling -o emacs in 'bin/sh/options.c',
create /usr/src/etc/root/dot.shrc with
set -o emacs
add to /usr/src/etc/root/dot.profile
ENV=$HOME/.shrc
export ENV
this way -o emacs will be called after /.profile has set a valid TERM
Patch attached with submission follows:
--- histedit.c.orig 2010-05-24 02:43:10.000000000 +0300
+++ histedit.c 2010-05-24 11:55:22.000000000 +0300
@@ -98,6 +98,8 @@
/*
* turn editing on
*/
+ char *term;
+
INTOFF;
if (el_in == NULL)
el_in = fdopen(0, "r");
@@ -107,6 +109,11 @@
el_out = fdopen(2, "w");
if (el_in == NULL || el_err == NULL || el_out == NULL)
goto bad;
+ term = lookupvar("TERM");
+ if (term)
+ setenv("TERM", term, 1);
+ else
+ unsetenv("TERM");
el = el_init(arg0, el_in, el_out, el_err);
if (el != NULL) {
if (hist)
@@ -160,6 +167,13 @@
}
}
+void
+setterm(const char *term)
+{
+ if (el != NULL && term != NULL)
+ el_set(el, EL_TERMINAL, term);
+}
+
int
histcmd(int argc, char **argv)
{
--- myhistedit.h.orig 2010-05-24 02:43:10.000000000 +0300
+++ myhistedit.h 2010-05-24 11:55:45.000000000 +0300
@@ -38,6 +38,7 @@
void histedit(void);
void sethistsize(const char *);
+void setterm(const char *);
int histcmd(int, char **);
int not_fcnumber(const char *);
int str_to_event(const char *, int);
--- var.c.orig 2010-05-24 02:43:10.000000000 +0300
+++ var.c 2010-05-24 12:03:07.000000000 +0300
@@ -80,6 +80,7 @@
#ifndef NO_HISTORY
struct var vhistsize;
+struct var vterm;
#endif
struct var vifs;
struct var vmail;
@@ -114,6 +115,10 @@
NULL },
{ &vps4, 0, "PS4=+ ",
NULL },
+#ifndef NO_HISTORY
+ { &vterm, VUNSET, "TERM=",
+ setterm },
+#endif
{ &voptind, 0, "OPTIND=1",
getoptsreset },
{ NULL, 0, NULL,
--- var.h.orig 2010-05-24 02:43:10.000000000 +0300
+++ var.h 2010-05-24 11:57:07.000000000 +0300
@@ -77,6 +77,7 @@
extern struct var vps4;
#ifndef NO_HISTORY
extern struct var vhistsize;
+extern struct var vterm;
#endif
/*
@@ -96,6 +97,7 @@
#define optindval() (voptind.text + 7)
#ifndef NO_HISTORY
#define histsizeval() (vhistsize.text + 9)
+#define termval() (vterm.text + 5)
#endif
#define mpathset() ((vmpath.flags & VUNSET) == 0)
>Release-Note:
>Audit-Trail:
>Unformatted:
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