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It appears that POSIX intends to add a -d X option to the read command 

in its next version, so it can be used as -d '' (to specify a \0 end
character for the record read, rather than the default \n) to accompany
find -print0 and xargs -0 options (also likely to be added).

Add support for -d now.   While here fix a bug where escaped nul
chars (\ \0) in non-raw mode were not being dropped, as they are
when not escaped (if not dropped, they're still not used in any
useful way, they just ended the value at that point).
This commit is contained in:
kre 2022-12-11 08:23:10 +00:00
parent eec672a55c
commit e2731928b1
2 changed files with 63 additions and 23 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

31
bin/sh/miscbltin.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: miscbltin.c,v 1.52 2022/08/19 12:52:31 kre Exp $ */
/* $NetBSD: miscbltin.c,v 1.53 2022/12/11 08:23:10 kre Exp $ */
/*-
* Copyright (c) 1991, 1993
@ -37,7 +37,7 @@
#if 0
static char sccsid[] = "@(#)miscbltin.c 8.4 (Berkeley) 5/4/95";
#else
__RCSID("$NetBSD: miscbltin.c,v 1.52 2022/08/19 12:52:31 kre Exp $");
__RCSID("$NetBSD: miscbltin.c,v 1.53 2022/12/11 08:23:10 kre Exp $");
#endif
#endif /* not lint */
@ -91,6 +91,7 @@ readcmd(int argc, char **argv)
{
char **ap;
char c;
char end;
int rflag;
char *prompt;
const char *ifs;
@ -102,13 +103,21 @@ readcmd(int argc, char **argv)
int saveall = 0;
ptrdiff_t wordlen = 0;
end = '\n'; /* record delimiter */
rflag = 0;
prompt = NULL;
while ((i = nextopt("p:r")) != '\0') {
if (i == 'p')
while ((i = nextopt("d:p:r")) != '\0') {
switch (i) {
case 'd':
end = *optionarg; /* even if '\0' */
break;
case 'p':
prompt = optionarg;
else
break;
case 'r':
rflag = 1;
break;
}
}
if (*(ap = argptr) == NULL)
@ -131,19 +140,19 @@ readcmd(int argc, char **argv)
status = 1;
break;
}
if (c == '\0')
continue;
if (c == '\\' && !rflag) {
if (c == '\\' && c != end && !rflag) {
if (read(0, &c, 1) != 1) {
status = 1;
break;
}
if (c != '\n')
if (c != '\n') /* \ \n is always just removed */
goto wdch;
continue;
}
if (c == '\n')
if (c == end)
break;
if (c == '\0')
continue;
if (strchr(ifs, c))
is_ifs = strchr(" \t\n", c) ? 1 : 2;
else
@ -167,6 +176,8 @@ readcmd(int argc, char **argv)
if (is_ifs == 0) {
wdch:;
if (c == '\0') /* always ignore attempts to input \0 */
continue;
/* append this character to the current variable */
startword = 0;
if (saveall)

55
bin/sh/sh.1
View File

@ -1,4 +1,4 @@
.\" $NetBSD: sh.1,v 1.251 2022/10/30 01:19:08 kre Exp $
.\" $NetBSD: sh.1,v 1.252 2022/12/11 08:23:10 kre Exp $
.\" Copyright (c) 1991, 1993
.\" The Regents of the University of California. All rights reserved.
.\"
@ -31,8 +31,7 @@
.\"
.\" @(#)sh.1 8.6 (Berkeley) 5/4/95
.\"
.\" RIP Noi, October 6, 1959 --
.Dd August 26, 2022
.Dd December 9, 2022
.Dt SH 1
.\" everything except c o and s (keep them ordered)
.ds flags abCEeFfhIiLlmnpquVvXx
@ -3583,15 +3582,21 @@ the program will use
and the built-in uses a separately cached value.
.\"
.Pp
.It Ic read Oo Fl p Ar prompt Oc Oo Fl r Oc Ar variable Op Ar ...
.It Ic read Oo Fl d Ar delim Oc Oo Fl p Ar prompt Oc Oo Fl r Oc Ar variable Op Ar ...
The
.Ar prompt
is printed on standard error if the
.Fl p
option is specified and the standard input is a terminal.
Then a line is read from the standard input.
The trailing newline is deleted from the
line and the line is split as described in the field splitting section of the
Then a record, terminated by the
first character of
.Ar delim
if the
.Fl d
option was given, or a newline character otherwise,
is read from the standard input.
The ending delimiter is deleted from the
record which is then split as described in the field splitting section of the
.Sx Word Expansions
section above.
The pieces are assigned to the
@ -3614,17 +3619,41 @@ which case failure is returned.
By default, unless the
.Fl r
option is specified, the backslash
.Dq \e
acts as an escape character, causing the following character to be treated
literally.
.Pq Ql \e
acts as an escape character,
causing the following character,
when that character is the escape character, or end delimiter character,
to be treated literally when reading the record.
This is the only form of quoting that applies.
If an unescaped backslash is followed by a newline,
the backslash and the newline will be deleted,
and replaced by the contents of the following line,
and replaced by the contents from the following line,
which is processed as if it had been part of the original line.
This includes reading yet more input if necessary,
until a line is read that is not terminated by
an unescaped backslash immediately before the newline.
until a line is read that contains or ends with an unescaped
copy of the delimiter character.
If the end delimiter (when it is not a newline) is escaoed,
it is treated as a normal character, and
.Ic read
continues looking for an unescaped end delimiter character.
No other escape sequences are meaningful, the escape character
is simply ignored.
This happens as the record is read,
before field splitting occurs.
When
.Fl r
is used,
no escaping occurs,
no line joining happens,
any input backslash is simply an input character.
.Pp
Note that if
.Ar delim
is given as an empty string, the nul character
.Pq Ql \e0
is used as the delimiter.
Other than this use, any nul characters in the input
stream are silently deleted.
.\"
.Pp
.It Ic readonly Ar name Ns Oo =value Oc ...