[src/trunk]: src/bin/sh Implement:

[kre <kre%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/652463a9c34c
branches:  trunk
changeset: 995225:652463a9c34c
user:      kre <kre%NetBSD.org@localhost>
date:      Wed Dec 12 11:51:33 2018 +0000

description:
Implement:
        readonly -q VAR...
        readonly -p VAR...
        export -q [-x] VAR...
        export -p [-x] VAR...

all available only in !SMALL shells - and while here, limit
"export -x" to full sized shells as well.

Also, do a better job of arg checking and validating of the
export and readonly commands (which is really just one built-in)
and of issuing error messages when something bogus is detected.

Since these commands are special builtin commands, any error
causes shell exit (for non-interactive shells).

diffstat:

 bin/sh/sh.1  |  123 ++++++++++++++++++++++++++++++++++-----
 bin/sh/var.c |  179 +++++++++++++++++++++++++++++++++++++++++++++-------------
 2 files changed, 242 insertions(+), 60 deletions(-)

diffs (truncated from 619 to 300 lines):

diff -r 9f21d292c8bc -r 652463a9c34c bin/sh/sh.1
--- a/bin/sh/sh.1       Wed Dec 12 11:40:08 2018 +0000
+++ b/bin/sh/sh.1       Wed Dec 12 11:51:33 2018 +0000
@@ -1,4 +1,4 @@
-.\"    $NetBSD: sh.1,v 1.212 2018/12/11 13:31:20 kre Exp $
+.\"    $NetBSD: sh.1,v 1.213 2018/12/12 11:51:33 kre Exp $
 .\" Copyright (c) 1991, 1993
 .\"    The Regents of the University of California.  All rights reserved.
 .\"
@@ -31,7 +31,7 @@
 .\"
 .\"    @(#)sh.1        8.6 (Berkeley) 5/4/95
 .\"
-.Dd December 11, 2018
+.Dd December 12, 2018
 .Dt SH 1
 .\" everything except c o and s (keep them ordered)
 .ds flags abCEeFfhIiLmnpquVvXx
@@ -2274,6 +2274,7 @@
 .It Ic \&: Op Ar arg ...
 A null command that returns a 0 (true) exit value.
 Any arguments or redirects are evaluated, then ignored.
+.\"
 .It Ic \&. Ar file
 The dot command reads and executes the commands from the specified
 .Ar file
@@ -2293,6 +2294,7 @@
 This implementation allows them to control loops surrounding the dot command,
 but obviously such behavior should not be relied on.
 It is now permitted by the standard, but not required.
+.\"
 .It Ic alias Op Ar name Ns Op Li = Ns Ar string ...
 If
 .Ar name Ns Li = Ns Ar string
@@ -2310,9 +2312,11 @@
 built-in prints the
 names and values of all defined aliases (see
 .Ic unalias ) .
+.\"
 .It Ic bg Op Ar job ...
 Continue the specified jobs (or the current job if no
 jobs are given) in the background.
+.\"
 .It Ic command Oo Fl pVv Oc Ar command Op Ar arg ...
 Execute the specified command but ignore shell functions when searching
 for it.
@@ -2335,6 +2339,7 @@
 search for the command and print the absolute pathname
 of utilities, the name for built-ins or the expansion of aliases.
 .El
+.\"
 .It Ic cd Oo Fl P Oc Op Ar directory Op Ar replace
 Switch to the specified directory (default
 .Ev $HOME ) .
@@ -2402,9 +2407,11 @@
 or if the
 .Ar replace
 argument was used.
+.\"
 .It Ic eval Ar string ...
 Concatenate all the arguments with spaces.
 Then re-parse and execute the command.
+.\"
 .It Ic exec Op Ar command Op Ar arg ...
 Unless
 .Ar command
@@ -2447,14 +2454,17 @@
 .Ic fdflags
 command below, which can set, or clear, this, and other,
 file descriptor flags.
+.\"
 .It Ic exit Op Ar exitstatus
 Terminate the shell process.
 If
 .Ar exitstatus
 is given it is used as the exit status of the shell; otherwise the
 exit status of the preceding command (the current value of $?) is used.
-.It Ic export Oo Fl npx Oc Ar name ...
-.It Ic export Fl p Op Fl x
+.\"
+.It Ic export Oo Fl nx Oc Ar name Ns Oo =value Oc ...
+.It Ic export Oo Fl x Oc Oo Fl p Oo Ar name ... Oc Oc
+.It Ic export Fl q Oo Fl x Oc Ar name ...
 With no options,
 but one or more names,
 the specified names are exported so that they will appear in the
@@ -2477,6 +2487,7 @@
 That is
 .Bd -literal -offset indent
 export -x FOO # FOO will now not be exported by default
+export FOO    # this command will fail (non-fatally)
 FOO=some_value my_command
 .Ed
 .Pp
@@ -2487,30 +2498,57 @@
 through the environment.
 .Pp
 The shell allows the value of a variable to be set at the
-same time it is exported by writing
+same time it is exported (or unexported, etc) by writing
 .Pp
-.Dl export name=value
+.Dl export [-nx] name=value
 .Pp
-With no arguments the export command lists the names of all exported variables,
+With no arguments the export command lists the names of all
+set exported variables,
 or if
 .Fl x
-was given, all variables marked not for export.
+was given, all set variables marked not for export.
 With the
 .Fl p
-option specified the output will be formatted suitably for non-interactive use.
+option specified, the output will be formatted suitably for
+non-interactive use, and unset variables are included.
+When
+.Fl p
+is given, variable names, but not values, may also be
+given, in which case output is limited to the variables named.
 .Pp
-The
+With
+.Fl q
+and a list of variable names, the
+.Ic export
+command will exit with status 0 if all the named
+variables have been marked for export, or 1 if
+any are not so marked.
+If
+.Fl x
+is also given,
+the test is instead for variables marked not to be exported.
+.Pp
+Other than with
+.Fl q ,
+the
 .Ic export
 built-in exits with status 0,
-unless an invalid option, or option combination, is given,
-or unless an attempt is made to export a variable which has
+unless an attempt is made to export a variable which has
 been marked as unavailable for export,
 in which cases it exits with status 1.
+In all cases if
+an invalid option, or option combination, is given,
+or an invalid variable name is present,
+.Ic export
+will write a message to the standard error output,
+and exit with a non-zero status.
+A non-interactive shell will terminate.
 .Pp
 Note that there is no restriction upon exporting,
 or un-exporting, read-only variables.
 The no-export flag can be reset by unsetting the variable
-and creating it again \(en provided it is not also read-only.
+and creating it again \(en provided the variable is not also read-only.
+.\"
 .It Ic fc Oo Fl e Ar editor Oc Op Ar first Op Ar last
 .It Ic fc Fl l Oo Fl nr Oc Op Ar first Op Ar last
 .It Ic fc Fl s Oo Ar old=new Oc Op Ar first
@@ -2602,10 +2640,12 @@
 .It Ev HISTSIZE
 The number of previous commands that are accessible.
 .El
+.\"
 .It Ic fg Op Ar job
 Move the specified job or the current job to the foreground.
 A foreground job can interact with the user via standard input,
 and receive signals from the terminal.
+.\"
 .It Ic fdflags Oo Fl v Oc Op Ar fd ...
 .It Ic fdflags Oo Fl v Oc Fl s Ar flags fd Op ...
 Get or set file descriptor flags.
@@ -2642,6 +2682,7 @@
 and
 .Xr open 2
 for more information.
+.\"
 .It Ic getopts Ar optstring var
 The POSIX
 .Ic getopts
@@ -2742,6 +2783,7 @@
 cmd \-carg -a file file
 cmd \-a \-carg \-\- file file
 .Ed
+.\"
 .It Ic hash Oo Fl rv Oc Op Ar command ...
 The shell maintains a hash table which remembers the
 locations of commands.
@@ -2765,11 +2807,13 @@
 .Fl r
 option causes the hash command to delete all the entries in the hash table
 except for functions.
+.\"
 .It Ic inputrc Ar file
 Read the
 .Ar file
 to set key bindings as defined by
 .Xr editrc 5 .
+.\"
 .It Ic jobid Oo Fl g Ns \&| Ns Fl j Ns \&| Ns Fl p Oc  Op Ar job
 With no flags, print the process identifiers of the processes in the job.
 If the
@@ -2815,6 +2859,7 @@
 .Fl p
 there is no process group leader (should not happen),
 and otherwise exits with status 0.
+.\"
 .It Ic jobs Oo Fl l Ns \&| Ns Fl p Oc Op Ar job ...
 Without
 .Ar job
@@ -2856,6 +2901,7 @@
 Non-interactive shells need to execute
 .Ic wait
 commands to clean up terminated background jobs.
+.\"
 .It Ic local Oo Fl INx Oc Oo Ar variable | \- Oc ...
 Define local variables for a function.
 Local variables have their attributes, and values,
@@ -3050,6 +3096,7 @@
 below for details of the effects of making the variable
 .Dv LINENO
 local.
+.\"
 .It Ic pwd Op Fl \&LP
 Print the current directory.
 If
@@ -3090,6 +3137,7 @@
 the program will use
 .Ev PWD
 and the built-in uses a separately cached value.
+.\"
 .It Ic read Oo Fl p Ar prompt Oc Oo Fl r Oc Ar variable Op Ar ...
 The
 .Ar prompt
@@ -3120,9 +3168,12 @@
 literally.
 If a backslash is followed by a newline, the backslash and the
 newline will be deleted.
-.It Ic readonly Ar name ...
-.It Ic readonly Op Fl p
-The specified names are marked as read only, so that they cannot be
+.\"
+.It Ic readonly Ar name Ns Oo =value Oc Ns ...
+.It Ic readonly Oo Fl p Op name... Oc
+.It Ic readonly Oo Fl q Oc name...
+With no options,
+the specified names are marked as read only, so that they cannot be
 subsequently modified or unset.
 The shell allows the value of a variable
 to be set at the same time it is marked read only by writing
@@ -3131,10 +3182,38 @@
 .Pp
 With no arguments the
 .Ic readonly
-command lists the names of all read only variables.
+command lists the names of all set read only variables.
 With the
 .Fl p
-option specified the output will be formatted suitably for non-interactive use.
+option specified,
+the output will be formatted suitably for non-interactive use,
+and unset variables are included.
+When the
+.Fl p
+option is given,
+a list of variable names (without values) may also be specified,
+in which case output is limited to the named variables.
+.Pp
+With the
+.Fl q
+option, the
+.Ic readonly
+command tests the read-only status of the variables listed
+and exits with status 0 if all named variables are read-only,
+or with status 1 if any are not read-only.
+.Pp
+Other than as specified for
+.Fl q
+the
+.Ic readonly
+command normally exits with status 0.
+In all cases, if an unknown option, or an invalid option combination,
+or an invalid variable name, is given;
+or a variable which was already read-only is attempted to be set;
+the exit status will not be zero, a diagnostic
+message will be written to the standard error output,
+and a non-interactive shell will terminate.
+.\"
 .It Ic return Op Ar n
 Stop executing the current function or a dot command with return value of
 .Ar n
@@ -3152,6 +3231,7 @@
 .Ic exit
 command instead, if you want to return from a script or exit
 your shell.
+.\"
 .It Ic set Oo { Fl options | Cm +options | Cm \-- } Oc Ar arg ...
 The