Changes that improve compatibility w/ the Sixth Edition (V6) UNIX Thompson shell are marked w/ a `C:' in the details below. ------------------------------------------------------------------------------- [osh-20081122]: mkconfig: * Added a case for DragonFly BSD (uname -s == DragonFly). osh.c: * Fixed a bug introduced in osh-20081026 where the shell incorrectly prints a process ID w/ an empty termination message upon receipt of the SIGINT signal in certain cases. For example: % sleep 10 | sleep 20 | sleep 30 ; wait ^C 2845: 2846: This example should only print three newlines to the standard error on SIGINT, not one newline and two process IDs w/ empty messages. Now, it behaves as expected. * Fixed a bug introduced in osh-20061230 where the shell incorrectly handles an unescaped terminating backslash (\) character at the end of string when the shell is invoked as `osh -c string'. In this case, the terminating backslash causes the shell to incorrectly read from the standard input at the end of string. For example: % osh -c 'echo Hello\' to\ you! Hello to you! This example should instead do nothing and exit w/ a zero status. For `osh -c string', an unescaped terminating backslash should turn string into a no-op. Now, it behaves as expected. ------------------------------------------------------------------------------- [osh-20081026]: * New files: defs.h, sh.h, util.c, v.c * Moved common definitions for all programs to "defs.h". * Added an osh package comment to the top of all header files. INSTALL, Makefile: * Changed the "oshall" target to only build osh since the utilities are now built into the shell. * Changed the "install-oshall" target to only install osh and its manual pages. This includes the utility manual pages since they are not fully documented elsewhere. mkconfig: * Changed the comment describing _XOPEN_SOURCE and _BSD_SOURCE for compiling the osh package to be more neutral. *.1.in: * Synced the manual pages w/ the code as needed. osh.c: * Include "sh.h" for needed declarations. * See "util.c:" below for integrated shell utilities description. * Renamed cmd_index() to cmd_lookup(), and changed the algorithm from a linear search to a binary search. * Added a base reallocation multiplier to glob()'s gavnew(). This doubles the number of new arguments for which to reallocate memory when the current allocation will not be large enough for the resulting argument vector. This reduces the number of realloc()s required for very large argument vectors while allowing the first malloc() to be a relatively small allocation for up to 126 matching file-name arguments. util.c: * Include "sh.h" for needed declarations. * Integrated the external `if', `goto', and `fd2' shell utilities as special built-in commands to improve shell performance. Also, added `echo' as a special built-in command. Osh executes each of these built-ins in a subshell. Consequently, the I/O for each can be redirected as before, and the argument list for each can be the result of a call to glob() as before. fd2.c: * Added a new `-e' command-line option to fd2. ------------------------------------------------------------------------------- [osh-20080629]: * Replaced all instances of "sdf1" w/ "v6shell" in all files since the osh project website has a new URL, http://v6shell.org/, as of Wednesday, 2008-01-16. * Changed the general contact email address and the bug report email address for the osh project. See the README file for details. * Changed instances of "Unix" to "UNIX" in all files (excluding C*). Though "Unix" is not an acronym, "UNIX" is a registered trademark of The Open Group (http://www.opengroup.org/tm-guidelines.htm). NOTE: The developer is not a lawyer and does not know that this change is necessary in the legal sense. In any case, it seems appropriate and sensible to acknowledge the UNIX trademark. * New files: sasignal.c (from OpenBSD /usr/src/lib/libc/gen/signal.c) and a corresponding sasignal.h LICENSE: * Added a copy of OpenBSD's license to account for sasignal.c . INSTALL, Makefile: * On Mac OS X, changed how compiling universal binaries is handled. Now, only MOXARCH is used to specify the target architecture(s) if and when the default (native) architecture is not desired. For example: % make MOXARCH='-arch i386 -arch ppc' or % make MOXARCH='-arch x86_64' * Made a few changes to the Makefile to allow for more flexibility in the compilation of the osh package. This should help on systems where GCC is not the default compiler and where /usr/bin/install is not a BSD-like or GNU-like install utility. mkconfig: * Add a case to define _XOPEN_SOURCE with a value of 600 on OpenSolaris 2008.05 (uname -s == SunOS), and generate an appropriate "config.h" file. Specifying "CC=/usr/bin/gcc" and "INSTALL=/usr/bin/ginstall" on the make command line allows osh to compile and install. osh.c: * Added support for 3 new command-line options (see osh(1)): `-i' == interactive shell `-l' == login shell `-v' == verbose shell * Added support for SYSCONFDIR/osh.oshrc (system-wide rc init file for interactive shells), SYSCONFDIR/osh.logout (system-wide rc logout file for login shells), and $h/.osh.logout (user rc logout file for login shells). * Added code to handle the SIGHUP signal. Cause the shell to execute its rc logout files (if any) upon receipt of this signal. * Changed the way that the shell deals w/ the SIGTERM signal so that it only sets SIGTERM to its default action for child processes if it was set to its default action when the shell started. Doing a `sigign + 15' causes the shell's child processes to ignore SIGTERM in all cases. * Changed the code to use sasignal() instead of signal(3). * Added a "Broken pipe" termination message for the SIGPIPE signal. Notice that the original shell did not print a termination message for this signal, but it can be quite useful in some cases. osh.1.in: * Updated the documentation as needed to reflect changes to the code. ------------------------------------------------------------------------------- [osh-20080109]: * New file: mkconfig (see Build/Install Changes) * Moved files: Moved manual pages from *.1 to *.1.in to make their generation and installation simpler in the Makefile. Build/Install Changes: * Stopped defining _XOPEN_SOURCE when compiling on Mac OS X, FreeBSD, NetBSD, and OpenBSD. It is simply not necessary. However, both _XOPEN_SOURCE and _BSD_SOURCE are necessary on GNU/Linux systems. * Added a simple configure script, mkconfig. It is automatically invoked from the Makefile to write out an appropriate "config.h" file according to the osh package's needs on the given system. It simply sets PATH_LOGIN, PATH_NEWGRP, _XOPEN_SOURCE, and _BSD_SOURCE as needed so that the user does not need to bother w/ doing it manually at build time. osh.c: * Patched the code to fix a "$0" parameter-substitution problem w/ the `source' command in the following interactive context: % cat >file echo \$0 == \"$0\" echo \$1 == \"$1\" ^D % source file ; : ... gives correct value for "$0". $0 == "" $1 == "" % source file arg ; : ... gives incorrect value for "$0". $0 == "0" $1 == "arg" getdolp() indirectly caused the problem by returning a NULL pointer when the intended result was a pointer to the empty string. This problem was not fatal, as the shell handles NULL pointers from getdolp() anyway. However, NULL is supposed to indicate an error where the specified parameter means nothing to the shell... For example: % echo \$Z == \"$Z\" $Z == "Z" * Changed the source command's parameter-substitution behavior so that $0 always results in the name of the sourced command file, not the name inherited from the main shell context. This makes the parameter-substitution behavior of sourced command files just like that of any other osh command file. Plus, this is the documented behavior. osh.1.in, sh6.1.in: * Revised some wording to remove some cases of possible ambiguity. ------------------------------------------------------------------------------- [osh-20070707]: * Added a new file, INSTALL, which contains build and install instructions. Made reference to INSTALL in Makefile and README. Makefile: * Added 3 new variables, MOXARCH, MOXSHELLARCH, and MOXUTILSARCH, to simplify building universal binaries for Mac OS X. These are unset by default. See INSTALL for more info. * Changed the default value for SYSCONFDIR from /etc to $(PREFIX)/etc. osh.c: * Changed the reserved file descriptors from (7 - 9) to (10 - 12) in order to avoid fd conflict w/ rxvt-unicode (version 8.2). This conflict prevented `chdir -' from functioning correctly, but this problem is now fixed. The problem was clearly visible when running an interactive instance of osh under the rxvt-unicode daemon (urxvtd) on Mac OS X. However, I never saw this type of conflict when running under any other type of terminal emulator on any OS. Thus, I do not know if this was only an osh problem, a urxvtd problem, a Mac OS X problem, or some combination of the 3... ------------------------------------------------------------------------------- [osh-20070324]: osh.c: * In main(), changed when fdfree() is called so that it is in a more ideal sequence with other operations according to how the shell is invoked (e.g., interactive shell vs. non-interactive shell). ------------------------------------------------------------------------------- [osh-20070321]: * Imported the project into a local subversion repository. * Changed the all of the code to "#include " and to use the "bool" data-type macro where appropriate. Makefile: * Added SYSCONFDIR and a new `man' target. osh.c: * Defined _PATH_SYSTEM_LOGIN as `SYSCONFDIR/**/"/osh.login"' instead of "/etc/osh.login" so that the user can use SYSCONFDIR (/etc by default) at build-time to specify the directory where the shell shall search for its system-wide initialization file. * Added a new special parameter, $v, which makes the version of the osh package available as a read-only string. The format is `osh-YYYYMMDD' for official releases and `osh-current (YYYYMMDD)' (interpreted as one word) for development snapshots. * Fixed a bug where interactive shells were no longer ignoring SIGTERM when invoked, as they are supposed to. Now, SIGTERM is being ignored again upon invocation of all interactive shells. * Fixed the output from doing a `sigign' so that it matches its documentation in osh.1: "..., a list is printed of those signals which are ignored by sigign in the current shell." Previously, the output from a `sigign' could be a little confusing. Now, its output only indicates those cases where a given signal is being ignored w/ the possibility that it can then be unignored (reset) in the current shell context. if.c: * Added 3 new primaries: -ef (equal files - same device, same inode), -nt (newer than), -ot (older than). See the if(1) manual page for full details. ------------------------------------------------------------------------------- [osh-20070131]: osh.1: * Made a few minimal changes to synchronize the manual w/ the code. osh.c 1.2 (jneitzel) 2007/01/14: * Changed the `chdir: No old directory' diagnostic to `chdir: No previous directory' to match the manual. ------------------------------------------------------------------------------- [osh-20061230]: The following files have been removed in this release: examples/*: These files are now available at: http://jneitzel.sdf1.org/osh/initialization_files/ tests/*: ... until I have a chance to rewrite them ... *.1: * Changed all instances of "UNIX" to "Unix" since the name of the "Unix" operating system is not an acronym. pexec.c: * Fixed a possible, but very unlikely, memory leak. osh.c: C: Rewrote the shell! It is now a combination of the ports of the original source code from sh6.c and glob6.c (see CHANGES-sh_to_sh6) w/ the prior enhancements which were found in osh-060124/osh*.[ch] . fd2.c: * Removed the call to lseek(2) to end-of-file for errors. The shell determines when this is necessary. * Changed the `: no shell' diagnostic to `: No shell!' in the spirit of sh6(1). goto.c: * Fixed a bug which interfered w/ finding a requested label when its first character had the high-order bit set. The value of the first character is now passed to getlabel() as an unsigned char converted to an int to allow correct comparison in such a case. if.c: * Removed the call to lseek(2) to end-of-file for errors. The shell determines when this is necessary. * Changed the method used to build the argument list for all commands executed by this utility, and removed the `Too many args' diagnostic. The maximum length of the argument list for a command is now limited only by the maximum length that the invoker can pass and by any system-imposed limit for execve(2) (see E2BIG in errno(2)). * Changed the `: no shell' diagnostic to `: No shell!' in the spirit of sh6(1). * Changed the diagnostic used for `!', `-a', `-o', and `(' operator errors from `: argument expected' to `: expression expected'. ------------------------------------------------------------------------------- [osh-060124]: Makefile: * Added targets for building/installing sh6(1) and glob6(1). Refer to the README file for further details. * Removed the `check-sh6' target since the tests were originally written for osh(1) and sh6(1) as Thompson-shell reimplementations, not ports. sh6: * Changed sh6(1) from being a reimplementation which is compiled from the same sources as osh(1) to being a port of the original Thompson shell from Sixth Edition UNIX. Refer to the CHANGES-sh_to_sh6 file for further details. osh: C: Treat both `( ; )' and `( & )' as syntax errors. C: Print the process ID for each command of an asynchronous pipeline, not just the last command. C: Added the `newgrp' special command. It is similar to `login' except that the newgrp(1) utility replaces the current interactive shell rather than the login(1) utility. * When opening `/dev/null' is needed for an asynchronous command, call open(2) w/ the O_RDONLY flag instead of O_RDWR. ------------------------------------------------------------------------------- [osh-051120]: This release fixes some problems introduced in osh-051030. [fios]*.1: * Made a few minimal changes for the sake of clarity. osh and sh6: * Fixed a file (pipe) descriptor leak in pipeline execution when the shell is interactive. This also includes those cases where the shell is executing an initialization file or sourcing a file from an interactive shell. Specifically, when the shell detected an error during execution of a pipeline, it did not close(2) all of the appropriate pipe descriptors which had been allocated by pipe(2) for the next command in the pipeline. * Reverted the unconventional execution error behavior introduced in the previous release since this change was out of character w/ the Thompson shell, and other common UNIX shells as well. osh only: * Fixed a bug in the `exec' special command where a pipeline such as `( cat /dev/zero ) | exec sleep 1' would not replace the current shell with an instance of sleep(1). ------------------------------------------------------------------------------- [osh-051030]: This release includes the following new files: fd2.[1c]: This is the fd2 utility from fd2-050215. pexec.[ch]: The pexec() function is used instead of execvp(3). See below for details. LICENSE: * Added an entry for pexec.c which mentions its being derived from the NetBSD project's /usr/src/lib/libc/gen/execvp.c and includes a copy of its original license. Of course, the pexec.c file also includes the pertinent license information. Makefile: * Added appropriate targets for building/installing the fd2 utility. The default is to build/install osh, if, goto, and fd2. examples: * Updated the example initialization files and command files. tests: * Made changes to the tests in accordance w/ changes to the software. *.1: * Made revisions in accordance w/ changes to the software. osh and sh6: * Did some more generic code cleanup and simplification. This was largely inspired by the fact that the developer was seeking workarounds for a few system bugs present in Mac OS X (Panther and Tiger). The system and library calls with some incorrect behavior include: lseek(2) - Panther only, fstat(2) and glob(3) - Tiger only. Since the bugs present in Panther differ from those in Tiger, the workarounds were removed for the sake of simplicity. However, the generic code cleanups remain. The observed problems for the shell in Mac OS X are very minor and do not interfere w/ using the shell in the normal case. The results from `make check' demonstrate the exceptional cases where Mac OS X impedes operation of the shell. * If the shell is invoked w/ an invalid argument list (argc == 0), exit w/ error and print the diagnostic `Invalid argument list'. * After the shell is invoked and initializes itself but before it begins reading/executing commands, close any open descriptors in the range 3 - 19 (inclusive) that the shell did not set up for itself. Note that doing so does not break x-only scripts if such scripts are supported on a particular UNIX system. * Increased some key buffer sizes... The size of the command-line buffer now allows for 2047 characters in each command line instead of 1023. The size of the argument list array now allows for 511 arguments in each command instead of 255. * Set the SIGCHLD signal to its default action when the shell starts. This is necessary on some systems because the shell's parent process might try to ignore SIGCHLD, and correct operation of the shell requires that zombies be created for its terminated children. Otherwise, the shell may not be able to properly waitpid(2) for, and report the termination status of, its children when they terminate. * The asynchronous and sequential process lists are no longer dynamically allocated. Now, these process lists are statically allocated, each allowing up to 64 process IDs. This is more than adequate in the normal case. Also, it has the benefit of a simpler implementation. A diagnostic is printed if the limits are exceeded. * The shell no longer uses execvp(3). Instead, it uses pexec() which is simply a derivation of NetBSD's execvp(3). This change allows the shell to deal with ENOEXEC errors in a way which is to similar to how the Thompson shell handled it. In addition, it allows the user to disable the searching of PATH for external commands. This is done by unsetting PATH or setting it to the empty string. * Instead of exiting with a status of 1 for some errors and a status of 2 for others, simply use a status of 2 to indicate that the shell has detected an error. See the `EXIT STATUS' section of the shell manual pages for the final word on the exit status of the shell. * Fixed a problem in how the shell exits on error when invoked w/ the `-c' option. The problem can be observed in ssh(1) by doing a `ssh user@host "syntax error >"' which requires the user to type an EOT (^D) (assuming input is a terminal) in order to cause the shell to exit. Now, the shell exits as it should. * A cleanup of the logic and code for shell termination on errors was also done. This is related to the problem mentioned above. Now, for the `-c' and `-t' options the shell does not affect the offset of the standard input when an error occurs. That is, it no longer calls lseek(2), simply calling exit(3) in such cases. * The shell now aborts execution of a command line when it detects an execution error that happens before calling fork(2). This can help in an interactive shell in particular. For example: 1) % wc -l data 66 data % chdir bad_dir; ( : ) >data chdir: bad directory % wc -l data 0 data 2) % wc -l data 66 data % chdir bad_dir; ( : ) >data chdir: bad directory % wc -l data 66 data In the first case, this obviously clobbers the file `data' which might be very undesirable if `data' is important. In the second case however, `data' is never clobbered since the failed `chdir' aborts execution of the command line. * If command-line overflow occurs on a terminal device, the shell no longer uses tcflush(3) to discard the overflowed characters. Instead, it simply reads and discards the remaining overflowed characters which have been received from the terminal for the overflowed line. * Changed when the shell generates termination reports for asynchronous processes. Instead of being generated after a command line is read and parsed, but before it is executed... They are now generated after a command line is executed. This prevents the possibility that the user might miss an important process termination if it is reported just before a screen-oriented text editor (like vi(1)) is invoked. Now, the process termination will be reported after the user quits the editor. osh only: * Eliminated all of the code for the run-time compatibility toggles. Trying to have 2 shells in one is simply not worth the increase in code size and complexity. If the user wants compatible only, the simple solution is to compile and run the shell as sh6(1). Otherwise, compile and run it as osh(1). * Eliminated the globbing behavior for failed matches which was like that found in the Bourne shell. Osh(1) now uses only the behavior found in the Thompson shell for failed matches. See the manual page for details, but in short the user may see a `No match' diagnostic. * Changed the effect of command-line overflow when it occurs in an initialization file. Previously, the shell would treat it as an error and lseek(2) to the end of the file. Now, the shell shall continue to read and execute commands from the file as if no error had occurred. Though, the `Command line overflow' diagnostic is still printed, and the exit status is set accordingly. * Added 2 new environment variables and 2 new special parameters. OSHDIR corresponds w/ `$d', and EXECSHELL corresponds w/ `$e'. See the osh(1) manual page for full details. * Made the shell to be more picky about correct usage for the `setenv', `unsetenv', and `umask' special commands. * The `source' special command can now substitute positional parameters. goto: * Reduced LABELSIZE from 1024 to 64. This allows a maximum label length of 63 characters, which is more than adequate. Assuming the user limits each possible label character to be one of [0-9A-Za-z], a label length limit of 63 characters still allows 8.33060e+112 possible unique labels. * Changed the way `label too long' is handled. Rather than giving a `label too long' error if a possible label found in a command file is too long, simply give this error when the user-requested label is longer than 63 characters. In such a case, no label search shall be performed at all. ------------------------------------------------------------------------------- [osh-050219]: examples: * Updated the example initialization files. * Added a few command files to give users a head start in scripting the shell. osh.1 and sh6.1: * Made a few more minimal revisions. osh and sh6: * Did some more code cleanup. ------------------------------------------------------------------------------- [osh-050131]: *.1: * Made some revisions and added some new content. osh and sh6: * Did some code cleanup for the sake of clarity and simplicity. Basically, this just removes some redundant operations. ------------------------------------------------------------------------------- [osh-041231]: LICENSE: * Removed clauses 3 and 4 from the license under which I release this software. This only affects my license. Do not worry; this software is still free! Read LICENSE for further info. Each file on which I explicitly claim copyright also contains a copy of this license. tests: * Added 2 more tests to be run by `make check' and `make check-sh6'. * Did some reorganization as well. osh and sh6: * Fixed a typo in the execute() function that can cause a memory fault in sh6, and in osh when running in compatible mode. This error was only possible when using the `chdir' special command preceded by a redirection such as `> file' (e.g., `> /dev/null chdir foo'). * Made several changes to how the shell reads input into the command-line buffer. Generally, this is not a user-visible change but is noteworthy nonetheless. * Made a few improvements to the parser. It now catches a few errors that could have previously caused some confusion. Before: `echo \<<', `echo \>>', `echo foo>bar', etc... None of these would have been considered a syntax error. Now, all of them are. The unquoted `<' and `>' characters in the above commands are not considered to be redirection arguments. In this implementation of the shell, a redirection argument must be separated from other command-line arguments by one or more blanks. This is unlike other shells. However, since this is the documented behavior of the Thompson shell, this implementation of the shell adheres to the documented behavior for the sake of simplicity. * Fixed incorrect globbing results for quoted glob characters. Now, the shell correctly handles quoted glob characters in an argument when the same argument also contains *unquoted* glob characters. Note that the correct behavior of globbing in the shell relies on a POSIX-compliant glob(3) being available on the system where the shell is built and/or used. osh only: * Fixed a small problem with the `source' special command. Doing a `source /path/to/nonexistent_file' in an initialization file should not cause the shell to cease execution of that file. Now, execution of the initialization file continues as normal. Of course, user can test for error and have the shell act accordingly in such a case. * Renamed the `trap' special command to `sigign' since it is really nothing like the trap command found in other shells. Thus, I thought calling it `trap' could be misleading to the user. On the other hand, `sigign' makes sense given what the command does, which is to ignore or unignore signals. if: * Did another rewrite of the if(1) utility. Started with a fresh copy of if.c from Sixth Edition UNIX. User-visible changes? None. goto: * Did another rewrite of the goto(1) utility. Started with a fresh copy of goto.c from Sixth Edition UNIX. User-visible changes? Yes, it is no longer an error for a NUL character to appear in the input. Also, it now prints an explicit `cannot seek' diagnostic if the input file is not seekable. ------------------------------------------------------------------------------- [osh-041028]: *.1: * Fixed a few typos in osh.1 and sh6.1. * Did a little fine tuning of osh.1 and sh6.1 to hopefully eliminate some incomplete and/or unclear explanations. * Did the same for both if.1 and goto.1. osh and sh6: * Fixed an annoying bug introduced in the previous release... The way error messages were printed in error() was not accounting for the fact that the standard error stream is quite often (if not always) unbuffered by default. This could make some error messages difficult to read when a pipeline was involved. A little example: Before (unfixed): % foo|bar|baz foo: not foundbar: not foundbaz: not found After (fixed): % foo|bar|baz foo: not found bar: not found baz: not found ------------------------------------------------------------------------------- [osh-041018]: This release includes sh6 in addition to osh, if, and goto. Sh6 is simply osh without the enhancements. It is built from the same sources as osh, but it is not built or installed by default. Makefile: * Added targets for sh6 so that it can optionally be built, tested, and installed if desired. osh and sh6: * Split the code into modules. This is primarily for developer sanity... ;) The new files are osh.h, main.c, parse.c, and exec.c. * If (geteuid() != getuid() || getegid() != getgid()) is true, print a nice error message and exit with a status of 2. * Strip all NUL characters from the shell's standard input as it is being read into the command line buffer. Input to the shell is expected to be text. * Changed the way the shell handles non-seekable files. This is for both initialization files (osh only) and command files. Do not block on open(2); open it and determine if it is a regular file (or seekable). If it is not a regular file or is not seekable, exit with an error. If seekable, reset the file for blocking I/O and continue as normal. Note that you can still read commands from FIFOs if you want. Instead of doing `osh myfifo', you can either do `osh for exit(3) so that Mac OS X doesn't complain. In fact, should be included for exit(3) on all systems as a simple matter of correctness. * Rename exp() to expr() to avoid conflicts w/ exp(3) on Mac OS X. Strange, as is not included there should not have been any conflict. Oh well, it is fixed now. * Enable this utility to return a meaningful exit status to the user. In short, `if foo = foo' returns an exit status of 0; `if foo = bar' returns an exit status of 1. Previously, exit status was always 0. * Made the usage less ambiguous; corrected the documentation to reflect the actual behavior. In short, usage is (and always has been) as follows: if expr [command [arg ...]] * Added some useful conditional primaries for constructing expressions. See the manual pages for details. * Use the stdio(3) functions instead of write(2) for printing the error messages. * In addition, added some useful diagnostic messages which were inspired by the test(1) utility from Seventh Edition UNIX. goto.c: * Give an error message when standard input is not seekable. Previously, a label not found error would be produced instead. fd2.c: * A new utility and manual page... It is an adaptation of the PWB/UNIX (roughly PWB/1.0 ?) redirect diagnostic output command. The original source came from the file `spencer_pwb.tar.gz' which can be found at: http://www.tuhs.org/Archive/PDP-11/Distributions/usdl/ ------------------------------------------------------------------------------- [osh-040421]: osh*.1: * Made various changes to hopefully improve the clarity. Added COMPATIBILITY, HISTORY, and NOTES sections. osh.c: C: Made changes to how the shell handles terminating `\' characters w/ the `-c' and `-t' flags. This is a simple extension of the same behavior exhibited when the shell is interactive or when it executes a command file, the only difference being that where a terminating `\' character causes the shell to read the next line of input in an interactive shell or command file, w/ the `-c' and `-t' flags the shell terminates w/o executing the command line. C: Allow parameter substitution w/ the `-c' and `-t' flags. This feature is not documented. For example, invoking the shell as follows allows parameter substitution to take place: % osh -t one two three echo $0 $1 $2 $3 -t one two three C: The shell now ignores SIGINT and SIGQUIT when the `-c' or `-t' flag is used. Thus, asynchronous commands invoked in this way ignore interrupts as they should. C: Ignore SIGINT and SIGQUIT for all commands started from asynchronous subshells. For example, `( sleep 300; some_command ) >outfile&' now ignores `^C' and `^\' as it should. C: Don't ignore SIGINT and SIGQUIT for asynchronous commands started in command files. If a command file is terminated by one of these signals, the asynchronous commands should also terminate. * Reverted a change made to termination reporting in osh-040216 that was not actually compatible w/ the V6 shell. * Always terminate the shell when read(2) fails. This fixes a possible infinite loop. * Fixed a bug in the parser that caused syntactically incorrect subshell commands not to be detected as such when preceded by redirection arguments (e.g., `outfile ( | )'). This bug was introduced in osh-040216. * Fixed possible buffer overflows in substparm(); added a new error message, "Too many characters", and made other changes necessary to properly deal w/ the new error condition. This problem had been present since at least osh-020214. * Made some changes to how globbing is handled by the shell. Specifically, glob(3) should only be called when an argument contains unquoted occurrences of any of the glob characters `*', `?', or `['. Previously, it was being called for every argument of an external command. This change improves run-time performance slightly as judged by time(1) and information returned by getrusage(2). * The above-mentioned change also allows the following compatibility feature. Added globbing compatibility when the shell is compiled w/ -DCLONE so that when no matches are found a diagnostic, "No match", is printed. ------------------------------------------------------------------------------- [osh-040216]: Makefile: * Use 'PREFIX?=' to allow passing PREFIX to make from the build environment. This is a BSD extension, but it appears that GNU make supports it as well. * Added a 'check' target to run a minimal test suite. osh.c: * Security fix: Always revoke set-id privileges. C: Redesigned and rewrote the parser. Now, parsing and execution are completely separate. This was the primary difference between the original implementation by Ken Thompson and this one. All remaining incompatibilities are quite minor by comparison. C: Don't perform globbing on the argument given to 'chdir'. It can be useful to glob in this case, but the V6 shell did not do this. So, this feature has been removed. C: Fixed the way that built-in commands are handled in pipelines. Built-in commands do not participate as elements of a pipeline the same way that external commands do. They neither read input from, nor write output to, a pipe. Data passed down the pipeline is lost. For example, `echo hello | chdir / | cat' still changes to /; it simply does not say hello. This same command line would have previously caused a file descriptor leak. C: Allow redirection arguments to appear before the command. Hence, the following examples are all identical to the shell: % cat outfile % outfile cat % outfile C: Allow parameter substitution for redirection arguments (e.g., 'command <$1', 'command >$1', and 'command >>$1'). C: Fixed annoying behavior when user types EOF not at the beginning of a line. Doing so previously was effectively the same as hitting 'return' in that unread input before the EOF would be read, parsed, and executed. It now matches the behavior of the V6 shell (mostly) and ignores the first EOF not at the beginning of a line. Three sequential EOFs (two in the V6 shell) will terminate the shell. Of course, typing EOF once at the beginning of a line immediately terminates the shell as it always has. C: Fixed incorrect handling of '\' at the end of an input line. One or any other 'odd' number of '\' characters at the end of an input line will continue the input onto the next line, while two or any other 'even' number of '\' characters will not. * Fixed handling of command line overflow when shell is interactive. The previous behavior could potentially be quite dangerous. At the least, it was very undesirable! Now, when overflow happens only one error message is printed, all unread data is flushed w/ tcflush(3), and a new prompt is printed. At this point, the shell will continue w/ its normal read/parse/execute loop as if nothing had happened. * Fixed some problems w/ termination reporting of async processes. For example, a `foo | bar | baz &' would mistaken try to report termination status for all three commands. Obviously, only the last command should be reported. * When a child process of the shell or a command file receives the SIGINT signal (e.g., user types '^C'), do not set termination status to zero. This matches the behavior of osh on V7, but it appears the V6 shell may have not have done this..? Non-zero termination status is certainly more desirable in this case. * Fixed a file descriptor leak that happened when redirection failed. For example, doing a `cat outfile' did not close 'infile' when 'outfile' could not be created. * Fixed incorrect behavior of the 'shift' special built-in command. '$0' was also being shifted. Now, '$0' remains constant during the life of a command file run. * Fixed some quoting abnormalities. The behavior did not match the V6 shell. This was caused primarily because of calling glob(3) w/o the GLOB_NOESCAPE flag. So, a backslash was lost when globargs() was called. Also, I accidently broke nested quoting in a previous release (e.g., '"word"' and/or "'word'"). All correct now! =) * Replaced the execv(3)/execvp(3) combo used when CLONE was defined in the Makefile. Simply use execvp(3) and document that the V6 shell always used '.:/bin:/usr/bin', not PATH. User can opt to set PATH appropriately if more clone-like behavior is desired. if.c: * Security fix: Always revoke set-id privileges. * Replaced the execv(3)/execvp(3) combo used when CLONE was defined in the Makefile. Simply use execvp(3) and document it as described above for osh.c. goto.c: * Use strcmp(3) to compare strings instead of reimplementing the same function internally. * Use the stdio(3) functions instead of write(2) for printing the error messages. * Changed how 'label too long' errors are handled. Now, when a label is encountered that happens to be too long print the line number w/ the error message and terminate the command file. ------------------------------------------------------------------------------- [osh-031112]: Makefile: * Added a test to ensure that destination directories exist. If a directory is missing, create it before trying to install the files. osh.c: C: Reverted some previous changes to abnormal termination messages. Specifically, the original on V6 used signal numbers instead of the "Alarm clock" and "Terminated" messages. C: When printing termination reports for asynchronous commands also print the process ID w/ the message. * Made changes/improvements to the detection of syntax errors for malformed pipelines. These syntax checks are done before actually creating any pipes; otherwise, there would be file descriptor leakage and possibly bad behavior when command lines have bad syntax. This is part one of a multipart fix. The most critical parsing problems are fixed now, but the problem of internal commands and pipelines still needs attention. * Fixed a file descriptor leak caused when user hits, or would exceed, the limit for maximum number of processes. * Added a missing newline to the 'Cannot pipe' error message. * Changed the prototype for xchdir() and made associated changes; only pass args[1] to this function, not the entire argument vector. * Avoid possible difficulties caused when commands begin w/ blanks (spaces, tabs) by stripping them away first. This has the benefit of simplifying some parts of the code, in addition to avoiding needless function calls when command lines contains only blanks. * Added code to make command files terminate when any of the commands cannot be executed, cannot be found, or terminate w/ a signal. ------------------------------------------------------------------------------- [osh-031014+]: The only noteworthy changes in this release are to the commentary in Makefile, NOTES, README, etc. ------------------------------------------------------------------------------- [osh-031014]: LICENSE: * Added additional license for code that I've written. osh.c: * Added an additional copyright notice. * Changed a char *pointer to a const char *pointer since it is only used for string constants. ------------------------------------------------------------------------------- [osh-031012]: A lot of the changes in this release are related to compatibility w/ the behavior of the original implementations from V6 and V7. In addition, the manual pages for "if" and "goto" have been changed to use man macros instead of escape sequences wherever possible as well as improving the appearance of the formatted output for the if(1) manual page. osh.c: C: Write the prompt to stderr instead of stdout. C: Added an exit command to terminate command files. C: Make the 'login' command only work in interactive shells and give an error message if not interactive. C: Changed the '>' and '>>' error message to 'cannot create' instead of 'cannot open'. C: Make '>>' create the file if it does not already exist. C: Added a 'shift: no args' error message for the 'shift' command when there is nothing to shift. C: Added "Hangup", "Alarm clock", and "Terminated" to the abnormal termination messages that osh reports. This matches osh on V7. C: Added code to properly report the abnormal termination status of asynchronous commands (&) upon receipt of the next command. This was documented in the V6 sh(1) manual page. * Fixed a problem where terminated children (zombies) could get in the way and render the shell unusable when the user reached hard or soft process limit. The shell's 'wait' command was, and still is, an effective way to exorcise these zombies. Although, this should be less necessary now that the above feature is implemented. * Avoid an infinite loop and give an error when the shell loses its input. An easy way to reproduce this is to close standard input from another shell w/ redirection. * Merged in code I use that makes 'chdir' more like 'cd' in modern shells by allowing 'chdir' to HOME, 'chdir -' to previous, and 'chdir dir' to any other directory. You can always define CLONE in the Makefile to compile w/ the original behavior if you wish. * Ignore '#!' at the beginning of command files. This is just for convenience. The original did not do this, but it makes sense since this implementation differs from the original by not taking any extra steps to feed executable text files to osh directly. Let the kernel do this for us. if.c: C: Added an exit command. * Added a 'cannot fork' error message. * Error messages are now written to stderr, not stdout. * Changed the '-r' and '-w' tests to use access(2) instead of open(2). This makes the '-w' test give correct results for directories where it previously failed to do so. * Match the documentation and give an error when the command in '{ command }' is another 'if'. * Temporarily removed the '-c' primitive from the code since it is undocumented and does not appear to do anything useful. goto.c: * Fixed a buffer overflow caused when the label was too long. It looks like this bug has been there since goto was written back in the 1970s. Also, reduced the maximum size of the buffer to 128 characters instead of LINE_MAX characters. * Added a 'label too long' error message to go w/ the above fix. * Error messages are now written to stderr, not stdout. * Replaced all of the gotos w/ while loops for the sake of clarity. ------------------------------------------------------------------------------- [osh-030811]: osh.c: * Fixed bug introduced in previous release by declaring array w/ incorrect size. This array is now dynamically allocated. if.c: * Added code to check and enforce maximum number of arguments. goto.c: * Completely fixed detection of EOF in command files. The reason for these EOF problems was because getchar(3) in V6 UNIX indicated end-of-file w/ '\0', and of course this is no longer the case today. ------------------------------------------------------------------------------- [osh-030730]: * This is the initial maintenance release by Jeffrey Allen Neitzel. osh.c: * Added '#ifdef CLONE' so the desired command search behavior can be chosen at build time. * Fixed segfault when command line contains only whitespace. We simply ignore this situation now. * Fixed segfault when redirections are used w/o a command. This will now result in a syntax error. * Fixed segfault when redirecting a command w/o a filename. This will now result in a syntax error. * Fixed a small memory leak when using redirection arguments. * Made osh correctly detect when a command line contains too many arguments. This allows command lines to have a maximum of 255 arguments. if.c: * Added '#ifdef CLONE' to make if(1) search for external commands the same way osh(1) does. goto.c: * Fixed a bug where goto should produce a 'label not found' error but would instead go into an infinite loop at the end of the command file. We now correctly detect EOF and successfully report 'label not found' errors. ------------------------------------------------------------------------------- [osh-020214]: * All releases of osh prior to and including 020214 were authored and maintained by Gunnar Ritter. Jeffrey Allen Neitzel 2008/11/16 @(#)$Id: CHANGES 559 2008-11-16 13:16:25Z jneitzel $