OpenBSD-4.6/bin/ksh/main.c
/* $OpenBSD: main.c,v 1.45 2009/01/29 23:27:26 jaredy Exp $ */
/*
* startup, main loop, environments and error handling
*/
#define EXTERN /* define EXTERNs in sh.h */
#include "sh.h"
#include <sys/stat.h>
#include <pwd.h>
extern char **environ;
/*
* global data
*/
static void reclaim(void);
static void remove_temps(struct temp *tp);
static int is_restricted(char *name);
static void init_username(void);
/*
* shell initialization
*/
static const char initifs[] = "IFS= \t\n";
static const char initsubs[] = "${PS2=> } ${PS3=#? } ${PS4=+ }";
static const char *initcoms [] = {
"typeset", "-r", "KSH_VERSION", NULL,
"typeset", "-x", "SHELL", "PATH", "HOME", NULL,
"typeset", "-i", "PPID", NULL,
"typeset", "-i", "OPTIND=1", NULL,
"eval", "typeset -i RANDOM MAILCHECK=\"${MAILCHECK-600}\" SECONDS=\"${SECONDS-0}\" TMOUT=\"${TMOUT-0}\"", NULL,
"alias",
/* Standard ksh aliases */
"hash=alias -t", /* not "alias -t --": hash -r needs to work */
"type=whence -v",
#ifdef JOBS
"stop=kill -STOP",
"suspend=kill -STOP $$",
#endif
"autoload=typeset -fu",
"functions=typeset -f",
#ifdef HISTORY
"history=fc -l",
#endif /* HISTORY */
"integer=typeset -i",
"nohup=nohup ",
"local=typeset",
"r=fc -e -",
/* Aliases that are builtin commands in at&t */
"login=exec login",
NULL,
/* this is what at&t ksh seems to track, with the addition of emacs */
"alias", "-tU",
"cat", "cc", "chmod", "cp", "date", "ed", "emacs", "grep", "ls",
"mail", "make", "mv", "pr", "rm", "sed", "sh", "vi", "who",
NULL,
NULL
};
char username[_PW_NAME_LEN + 1];
#define version_param (initcoms[2])
int
main(int argc, char *argv[])
{
int i;
int argi;
Source *s;
struct block *l;
int restricted, errexit;
char **wp;
struct env env;
pid_t ppid;
/* make sure argv[] is sane */
if (!*argv) {
static const char *empty_argv[] = {
"ksh", (char *) 0
};
argv = (char **) empty_argv;
argc = 1;
}
kshname = *argv;
ainit(&aperm); /* initialize permanent Area */
/* set up base environment */
memset(&env, 0, sizeof(env));
env.type = E_NONE;
ainit(&env.area);
e = &env;
newblock(); /* set up global l->vars and l->funs */
/* Do this first so output routines (eg, errorf, shellf) can work */
initio();
initvar();
initctypes();
inittraps();
coproc_init();
/* set up variable and command dictionaries */
ktinit(&taliases, APERM, 0);
ktinit(&aliases, APERM, 0);
ktinit(&homedirs, APERM, 0);
/* define shell keywords */
initkeywords();
/* define built-in commands */
ktinit(&builtins, APERM, 64); /* must be 2^n (currently 40 builtins) */
for (i = 0; shbuiltins[i].name != NULL; i++)
builtin(shbuiltins[i].name, shbuiltins[i].func);
for (i = 0; kshbuiltins[i].name != NULL; i++)
builtin(kshbuiltins[i].name, kshbuiltins[i].func);
init_histvec();
def_path = _PATH_DEFPATH;
{
size_t len = confstr(_CS_PATH, (char *) 0, 0);
char *new;
if (len > 0) {
confstr(_CS_PATH, new = alloc(len + 1, APERM), len + 1);
def_path = new;
}
}
/* Set PATH to def_path (will set the path global variable).
* (import of environment below will probably change this setting).
*/
{
struct tbl *vp = global("PATH");
/* setstr can't fail here */
setstr(vp, def_path, KSH_RETURN_ERROR);
}
/* Turn on nohup by default for now - will change to off
* by default once people are aware of its existence
* (at&t ksh does not have a nohup option - it always sends
* the hup).
*/
Flag(FNOHUP) = 1;
/* Turn on brace expansion by default. At&t ksh's that have
* alternation always have it on. BUT, posix doesn't have
* brace expansion, so set this before setting up FPOSIX
* (change_flag() clears FBRACEEXPAND when FPOSIX is set).
*/
#ifdef BRACE_EXPAND
Flag(FBRACEEXPAND) = 1;
#endif /* BRACE_EXPAND */
/* set posix flag just before environment so that it will have
* exactly the same effect as the POSIXLY_CORRECT environment
* variable. If this needs to be done sooner to ensure correct posix
* operation, an initial scan of the environment will also have
* done sooner.
*/
#ifdef POSIXLY_CORRECT
change_flag(FPOSIX, OF_SPECIAL, 1);
#endif /* POSIXLY_CORRECT */
/* Check to see if we're /bin/sh. */
if (!strcmp(kshname, "sh") || !strcmp(kshname, "-sh") ||
(strlen(kshname) >= 3 &&
!strcmp(&kshname[strlen(kshname) - 3], "/sh"))) {
Flag(FSH) = 1;
version_param = "SH_VERSION";
}
/* Set edit mode to emacs by default, may be overridden
* by the environment or the user. Also, we want tab completion
* on in vi by default. */
#if defined(EDIT) && defined(EMACS)
change_flag(FEMACS, OF_SPECIAL, 1);
#endif /* EDIT && EMACS */
#if defined(EDIT) && defined(VI)
Flag(FVITABCOMPLETE) = 1;
#endif /* EDIT && VI */
/* import environment */
if (environ != NULL)
for (wp = environ; *wp != NULL; wp++)
typeset(*wp, IMPORT|EXPORT, 0, 0, 0);
kshpid = procpid = getpid();
typeset(initifs, 0, 0, 0, 0); /* for security */
/* assign default shell variable values */
substitute(initsubs, 0);
/* Figure out the current working directory and set $PWD */
{
struct stat s_pwd, s_dot;
struct tbl *pwd_v = global("PWD");
char *pwd = str_val(pwd_v);
char *pwdx = pwd;
/* Try to use existing $PWD if it is valid */
if (pwd[0] != '/' ||
stat(pwd, &s_pwd) < 0 || stat(".", &s_dot) < 0 ||
s_pwd.st_dev != s_dot.st_dev ||
s_pwd.st_ino != s_dot.st_ino)
pwdx = (char *) 0;
set_current_wd(pwdx);
if (current_wd[0])
simplify_path(current_wd);
/* Only set pwd if we know where we are or if it had a
* bogus value
*/
if (current_wd[0] || pwd != null)
/* setstr can't fail here */
setstr(pwd_v, current_wd, KSH_RETURN_ERROR);
}
ppid = getppid();
setint(global("PPID"), (long) ppid);
/* setstr can't fail here */
setstr(global(version_param), ksh_version, KSH_RETURN_ERROR);
/* execute initialization statements */
for (wp = (char**) initcoms; *wp != NULL; wp++) {
shcomexec(wp);
for (; *wp != NULL; wp++)
;
}
ksheuid = geteuid();
init_username();
safe_prompt = ksheuid ? "$ " : "# ";
{
struct tbl *vp = global("PS1");
/* Set PS1 if it isn't set, or we are root and prompt doesn't
* contain a # or \$ (only in ksh mode).
*/
if (!(vp->flag & ISSET) ||
(!ksheuid && !strchr(str_val(vp), '#') &&
(Flag(FSH) || !strstr(str_val(vp), "\\$"))))
/* setstr can't fail here */
setstr(vp, safe_prompt, KSH_RETURN_ERROR);
}
/* Set this before parsing arguments */
Flag(FPRIVILEGED) = getuid() != ksheuid || getgid() != getegid();
/* this to note if monitor is set on command line (see below) */
Flag(FMONITOR) = 127;
argi = parse_args(argv, OF_CMDLINE, (int *) 0);
if (argi < 0)
exit(1);
if (Flag(FCOMMAND)) {
s = pushs(SSTRING, ATEMP);
if (!(s->start = s->str = argv[argi++]))
errorf("-c requires an argument");
if (argv[argi])
kshname = argv[argi++];
} else if (argi < argc && !Flag(FSTDIN)) {
s = pushs(SFILE, ATEMP);
s->file = argv[argi++];
s->u.shf = shf_open(s->file, O_RDONLY, 0, SHF_MAPHI|SHF_CLEXEC);
if (s->u.shf == NULL) {
exstat = 127; /* POSIX */
errorf("%s: %s", s->file, strerror(errno));
}
kshname = s->file;
} else {
Flag(FSTDIN) = 1;
s = pushs(SSTDIN, ATEMP);
s->file = "<stdin>";
s->u.shf = shf_fdopen(0, SHF_RD | can_seek(0),
(struct shf *) 0);
if (isatty(0) && isatty(2)) {
Flag(FTALKING) = Flag(FTALKING_I) = 1;
/* The following only if isatty(0) */
s->flags |= SF_TTY;
s->u.shf->flags |= SHF_INTERRUPT;
s->file = (char *) 0;
}
}
/* This bizarreness is mandated by POSIX */
{
struct stat s_stdin;
if (fstat(0, &s_stdin) >= 0 && S_ISCHR(s_stdin.st_mode) &&
Flag(FTALKING))
reset_nonblock(0);
}
/* initialize job control */
i = Flag(FMONITOR) != 127;
Flag(FMONITOR) = 0;
j_init(i);
#ifdef EDIT
/* Do this after j_init(), as tty_fd is not initialized 'til then */
if (Flag(FTALKING))
x_init();
#endif
l = e->loc;
l->argv = &argv[argi - 1];
l->argc = argc - argi;
l->argv[0] = (char *) kshname;
getopts_reset(1);
/* Disable during .profile/ENV reading */
restricted = Flag(FRESTRICTED);
Flag(FRESTRICTED) = 0;
errexit = Flag(FERREXIT);
Flag(FERREXIT) = 0;
/* Do this before profile/$ENV so that if it causes problems in them,
* user will know why things broke.
*/
if (!current_wd[0] && Flag(FTALKING))
warningf(false, "Cannot determine current working directory");
if (Flag(FLOGIN)) {
include(KSH_SYSTEM_PROFILE, 0, (char **) 0, 1);
if (!Flag(FPRIVILEGED))
include(substitute("$HOME/.profile", 0), 0,
(char **) 0, 1);
}
if (Flag(FPRIVILEGED))
include("/etc/suid_profile", 0, (char **) 0, 1);
else if (Flag(FTALKING)) {
char *env_file;
/* include $ENV */
env_file = str_val(global("ENV"));
#ifdef DEFAULT_ENV
/* If env isn't set, include default environment */
if (env_file == null)
env_file = DEFAULT_ENV;
#endif /* DEFAULT_ENV */
env_file = substitute(env_file, DOTILDE);
if (*env_file != '\0')
include(env_file, 0, (char **) 0, 1);
}
if (is_restricted(argv[0]) || is_restricted(str_val(global("SHELL"))))
restricted = 1;
if (restricted) {
static const char *const restr_com[] = {
"typeset", "-r", "PATH",
"ENV", "SHELL",
(char *) 0
};
shcomexec((char **) restr_com);
/* After typeset command... */
Flag(FRESTRICTED) = 1;
}
if (errexit)
Flag(FERREXIT) = 1;
if (Flag(FTALKING)) {
hist_init(s);
alarm_init();
} else
Flag(FTRACKALL) = 1; /* set after ENV */
shell(s, true); /* doesn't return */
return 0;
}
static void
init_username(void)
{
char *p;
struct tbl *vp = global("USER");
if (vp->flag & ISSET)
p = ksheuid == 0 ? "root" : str_val(vp);
else
p = getlogin();
strlcpy(username, p != NULL ? p : "?", sizeof username);
}
int
include(const char *name, int argc, char **argv, int intr_ok)
{
Source *volatile s = NULL;
struct shf *shf;
char **volatile old_argv;
volatile int old_argc;
int i;
shf = shf_open(name, O_RDONLY, 0, SHF_MAPHI|SHF_CLEXEC);
if (shf == NULL)
return -1;
if (argv) {
old_argv = e->loc->argv;
old_argc = e->loc->argc;
} else {
old_argv = (char **) 0;
old_argc = 0;
}
newenv(E_INCL);
i = sigsetjmp(e->jbuf, 0);
if (i) {
quitenv(s ? s->u.shf : NULL);
if (old_argv) {
e->loc->argv = old_argv;
e->loc->argc = old_argc;
}
switch (i) {
case LRETURN:
case LERROR:
return exstat & 0xff; /* see below */
case LINTR:
/* intr_ok is set if we are including .profile or $ENV.
* If user ^C's out, we don't want to kill the shell...
*/
if (intr_ok && (exstat - 128) != SIGTERM)
return 1;
/* FALLTHROUGH */
case LEXIT:
case LLEAVE:
case LSHELL:
unwind(i);
/* NOTREACHED */
default:
internal_errorf(1, "include: %d", i);
/* NOTREACHED */
}
}
if (argv) {
e->loc->argv = argv;
e->loc->argc = argc;
}
s = pushs(SFILE, ATEMP);
s->u.shf = shf;
s->file = str_save(name, ATEMP);
i = shell(s, false);
quitenv(s->u.shf);
if (old_argv) {
e->loc->argv = old_argv;
e->loc->argc = old_argc;
}
return i & 0xff; /* & 0xff to ensure value not -1 */
}
int
command(const char *comm)
{
Source *s;
s = pushs(SSTRING, ATEMP);
s->start = s->str = comm;
return shell(s, false);
}
/*
* run the commands from the input source, returning status.
*/
int
shell(Source *volatile s, volatile int toplevel)
{
struct op *t;
volatile int wastty = s->flags & SF_TTY;
volatile int attempts = 13;
volatile int interactive = Flag(FTALKING) && toplevel;
Source *volatile old_source = source;
int i;
newenv(E_PARSE);
if (interactive)
really_exit = 0;
i = sigsetjmp(e->jbuf, 0);
if (i) {
switch (i) {
case LINTR: /* we get here if SIGINT not caught or ignored */
case LERROR:
case LSHELL:
if (interactive) {
if (i == LINTR)
shellf(newline);
/* Reset any eof that was read as part of a
* multiline command.
*/
if (Flag(FIGNOREEOF) && s->type == SEOF &&
wastty)
s->type = SSTDIN;
/* Used by exit command to get back to
* top level shell. Kind of strange since
* interactive is set if we are reading from
* a tty, but to have stopped jobs, one only
* needs FMONITOR set (not FTALKING/SF_TTY)...
*/
/* toss any input we have so far */
s->start = s->str = null;
break;
}
/* FALLTHROUGH */
case LEXIT:
case LLEAVE:
case LRETURN:
source = old_source;
quitenv(NULL);
unwind(i); /* keep on going */
/* NOTREACHED */
default:
source = old_source;
quitenv(NULL);
internal_errorf(1, "shell: %d", i);
/* NOTREACHED */
}
}
while (1) {
if (trap)
runtraps(0);
if (s->next == NULL) {
if (Flag(FVERBOSE))
s->flags |= SF_ECHO;
else
s->flags &= ~SF_ECHO;
}
if (interactive) {
j_notify();
mcheck();
set_prompt(PS1, s);
}
t = compile(s);
if (t != NULL && t->type == TEOF) {
if (wastty && Flag(FIGNOREEOF) && --attempts > 0) {
shellf("Use `exit' to leave ksh\n");
s->type = SSTDIN;
} else if (wastty && !really_exit &&
j_stopped_running()) {
really_exit = 1;
s->type = SSTDIN;
} else {
/* this for POSIX, which says EXIT traps
* shall be taken in the environment
* immediately after the last command
* executed.
*/
if (toplevel)
unwind(LEXIT);
break;
}
}
if (t && (!Flag(FNOEXEC) || (s->flags & SF_TTY)))
exstat = execute(t, 0, NULL);
if (t != NULL && t->type != TEOF && interactive && really_exit)
really_exit = 0;
reclaim();
}
quitenv(NULL);
source = old_source;
return exstat;
}
/* return to closest error handler or shell(), exit if none found */
void
unwind(int i)
{
/* ordering for EXIT vs ERR is a bit odd (this is what at&t ksh does) */
if (i == LEXIT || (Flag(FERREXIT) && (i == LERROR || i == LINTR) &&
sigtraps[SIGEXIT_].trap)) {
runtrap(&sigtraps[SIGEXIT_]);
i = LLEAVE;
} else if (Flag(FERREXIT) && (i == LERROR || i == LINTR)) {
runtrap(&sigtraps[SIGERR_]);
i = LLEAVE;
}
while (1) {
switch (e->type) {
case E_PARSE:
case E_FUNC:
case E_INCL:
case E_LOOP:
case E_ERRH:
siglongjmp(e->jbuf, i);
/* NOTREACHED */
case E_NONE:
if (i == LINTR)
e->flags |= EF_FAKE_SIGDIE;
/* FALLTHROUGH */
default:
quitenv(NULL);
}
}
}
void
newenv(int type)
{
struct env *ep;
ep = (struct env *) alloc(sizeof(*ep), ATEMP);
ep->type = type;
ep->flags = 0;
ainit(&ep->area);
ep->loc = e->loc;
ep->savefd = NULL;
ep->oenv = e;
ep->temps = NULL;
e = ep;
}
void
quitenv(struct shf *shf)
{
struct env *ep = e;
int fd;
if (ep->oenv && ep->oenv->loc != ep->loc)
popblock();
if (ep->savefd != NULL) {
for (fd = 0; fd < NUFILE; fd++)
/* if ep->savefd[fd] < 0, means fd was closed */
if (ep->savefd[fd])
restfd(fd, ep->savefd[fd]);
if (ep->savefd[2]) /* Clear any write errors */
shf_reopen(2, SHF_WR, shl_out);
}
/* Bottom of the stack.
* Either main shell is exiting or cleanup_parents_env() was called.
*/
if (ep->oenv == NULL) {
if (ep->type == E_NONE) { /* Main shell exiting? */
if (Flag(FTALKING))
hist_finish();
j_exit();
if (ep->flags & EF_FAKE_SIGDIE) {
int sig = exstat - 128;
/* ham up our death a bit (at&t ksh
* only seems to do this for SIGTERM)
* Don't do it for SIGQUIT, since we'd
* dump a core..
*/
if ((sig == SIGINT || sig == SIGTERM) &&
getpgrp() == kshpid) {
setsig(&sigtraps[sig], SIG_DFL,
SS_RESTORE_CURR|SS_FORCE);
kill(0, sig);
}
}
}
if (shf)
shf_close(shf);
reclaim();
exit(exstat);
}
if (shf)
shf_close(shf);
reclaim();
e = e->oenv;
afree(ep, ATEMP);
}
/* Called after a fork to cleanup stuff left over from parents environment */
void
cleanup_parents_env(void)
{
struct env *ep;
int fd;
/* Don't clean up temporary files - parent will probably need them.
* Also, can't easily reclaim memory since variables, etc. could be
* anywhere.
*/
/* close all file descriptors hiding in savefd */
for (ep = e; ep; ep = ep->oenv) {
if (ep->savefd) {
for (fd = 0; fd < NUFILE; fd++)
if (ep->savefd[fd] > 0)
close(ep->savefd[fd]);
afree(ep->savefd, &ep->area);
ep->savefd = (short *) 0;
}
}
e->oenv = (struct env *) 0;
}
/* Called just before an execve cleanup stuff temporary files */
void
cleanup_proc_env(void)
{
struct env *ep;
for (ep = e; ep; ep = ep->oenv)
remove_temps(ep->temps);
}
/* remove temp files and free ATEMP Area */
static void
reclaim(void)
{
remove_temps(e->temps);
e->temps = NULL;
afreeall(&e->area);
}
static void
remove_temps(struct temp *tp)
{
for (; tp != NULL; tp = tp->next)
if (tp->pid == procpid) {
unlink(tp->name);
}
}
/* Returns true if name refers to a restricted shell */
static int
is_restricted(char *name)
{
char *p;
if ((p = strrchr(name, '/')))
name = p;
/* accepts rsh, rksh, rpdksh, pdrksh, etc. */
return (p = strchr(name, 'r')) && strstr(p, "sh");
}