/* $NetBSD: main.c,v 1.82.2.2 2021/11/06 13:35:43 martin Exp $ */ /*- * Copyright (c) 1991, 1993 * The Regents of the University of California. All rights reserved. * * This code is derived from software contributed to Berkeley by * Kenneth Almquist. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ #include #ifndef lint __COPYRIGHT("@(#) Copyright (c) 1991, 1993\ The Regents of the University of California. All rights reserved."); #endif /* not lint */ #ifndef lint #if 0 static char sccsid[] = "@(#)main.c 8.7 (Berkeley) 7/19/95"; #else __RCSID("$NetBSD: main.c,v 1.82.2.2 2021/11/06 13:35:43 martin Exp $"); #endif #endif /* not lint */ #include #include #include #include #include #include #include #include #include #include "shell.h" #include "main.h" #include "mail.h" #include "options.h" #include "builtins.h" #include "output.h" #include "parser.h" #include "nodes.h" #include "expand.h" #include "eval.h" #include "jobs.h" #include "input.h" #include "trap.h" #include "var.h" #include "show.h" #include "memalloc.h" #include "error.h" #include "init.h" #include "mystring.h" #include "exec.h" #include "cd.h" #include "redir.h" #define PROFILE 0 int rootpid; int rootshell; struct jmploc main_handler; int max_user_fd; bool privileged; #if PROFILE short profile_buf[16384]; extern int etext(); #endif STATIC void read_profile(const char *); /* * Main routine. We initialize things, parse the arguments, execute * profiles if we're a login shell, and then call cmdloop to execute * commands. The setjmp call sets up the location to jump to when an * exception occurs. When an exception occurs the variable "state" * is used to figure out how far we had gotten. */ int main(int argc, char **argv) { struct stackmark smark; volatile int state; char *shinit; uid_t uid; gid_t gid; sigset_t mask; bool waspriv; /* * If we happen to be invoked with SIGCHLD ignored, we cannot * successfully do almost anything. Perhaps we should remember * its state and pass it on ignored to children if it was ignored * on entry, but that seems like just leaving the shit on the * footpath for someone else to fall into... */ (void)signal(SIGCHLD, SIG_DFL); /* * Similarly, SIGCHLD must not be blocked */ sigemptyset(&mask); sigaddset(&mask, SIGCHLD); sigprocmask(SIG_UNBLOCK, &mask, NULL); uid = getuid(); gid = getgid(); waspriv = privileged = (uid != geteuid()) || (gid != getegid()); max_user_fd = fcntl(0, F_MAXFD); if (max_user_fd < 2) max_user_fd = 2; setlocale(LC_ALL, ""); posix = getenv("POSIXLY_CORRECT") != NULL; #if PROFILE monitor(4, etext, profile_buf, sizeof profile_buf, 50); #endif state = 0; if (setjmp(main_handler.loc)) { /* * When a shell procedure is executed, we raise the * exception EXSHELLPROC to clean up before executing * the shell procedure. */ switch (exception) { case EXSHELLPROC: rootpid = getpid(); rootshell = 1; minusc = NULL; state = 3; break; case EXEXEC: exitstatus = exerrno; break; case EXERROR: exitstatus = 2; break; default: break; } if (exception != EXSHELLPROC) { if (state == 0 || iflag == 0 || ! rootshell || exception == EXEXIT) exitshell(exitstatus); } reset(); if (exception == EXINT) { out2c('\n'); flushout(&errout); } popstackmark(&smark); FORCEINTON; /* enable interrupts */ if (state == 1) goto state1; else if (state == 2) goto state2; else if (state == 3) goto state3; else goto state4; } handler = &main_handler; #ifdef DEBUG #if DEBUG >= 2 debug = 1; /* this may be reset by procargs() later */ #endif opentrace(); if (privileged) trputs("Privileged "); trputs("Shell args: "); trargs(argv); #if DEBUG >= 3 set_debug(((DEBUG)==3 ? "_@" : "++"), 1); #endif #endif rootpid = getpid(); rootshell = 1; init(); initpwd(); setstackmark(&smark); procargs(argc, argv); #if 0 /* This now happens (indirectly) in the procargs() just above */ /* * Limit bogus system(3) or popen(3) calls in setuid binaries, * by requiring the -p flag */ if (!pflag && (uid != geteuid() || gid != getegid())) { setuid(uid); setgid(gid); /* PS1 might need to be changed accordingly. */ choose_ps1(); } #else /* except for this one little bit */ if (waspriv && !privileged) choose_ps1(); #endif if (argv[0] && argv[0][0] == '-') { state = 1; read_profile("/etc/profile"); state1: state = 2; if (!privileged) { char *profile; const char *home; home = lookupvar("HOME"); if (home == NULL) home = nullstr; profile = ststrcat(NULL, home, "/.profile", STSTRC_END); read_profile(profile); stunalloc(profile); } #if 0 /* FreeBSD does (effectively) ...*/ else read_profile("/etc/suid_profile"); #endif } state2: state = 3; if ((iflag || !posix) && !privileged) { struct stackmark env_smark; setstackmark(&env_smark); if ((shinit = lookupvar("ENV")) != NULL && *shinit != '\0') { state = 3; read_profile(expandenv(shinit)); } popstackmark(&env_smark); } state3: state = 4; line_number = 1; /* undo anything from profile files */ if (sflag == 0 || minusc) { static int sigs[] = { SIGINT, SIGQUIT, SIGHUP, #ifdef SIGTSTP SIGTSTP, #endif SIGPIPE }; #define SIGSSIZE (sizeof(sigs)/sizeof(sigs[0])) size_t i; for (i = 0; i < SIGSSIZE; i++) setsignal(sigs[i], 0); } rststackmark(&smark); /* this one is never popped */ if (minusc) evalstring(minusc, sflag ? 0 : EV_EXIT); if (sflag || minusc == NULL) { state4: /* XXX ??? - why isn't this before the "if" statement */ cmdloop(1); if (iflag) { out2str("\n"); flushout(&errout); } } #if PROFILE monitor(0); #endif line_number = plinno; exitshell(exitstatus); /* NOTREACHED */ } /* * Read and execute commands. "Top" is nonzero for the top level command * loop; it turns on prompting if the shell is interactive. */ void cmdloop(int top) { union node *n; struct stackmark smark; int inter; int numeof = 0; enum skipstate skip; CTRACE(DBG_ALWAYS, ("cmdloop(%d) called\n", top)); setstackmark(&smark); for (;;) { if (pendingsigs) dotrap(); inter = 0; if (iflag == 1 && top) { inter = 1; showjobs(out2, SHOW_CHANGED); chkmail(0); flushout(&errout); nflag = 0; } n = parsecmd(inter); VXTRACE(DBG_PARSE|DBG_EVAL|DBG_CMDS,("cmdloop: "),showtree(n)); if (n == NEOF) { if (!top || numeof >= 50) break; if (nflag) break; if (!stoppedjobs()) { if (!iflag || !Iflag) break; out2str("\nUse \"exit\" to leave shell.\n"); } numeof++; } else if (n != NULL && nflag == 0) { job_warning = (job_warning == 2) ? 1 : 0; numeof = 0; evaltree(n, 0); } rststackmark(&smark); /* * Any SKIP* can occur here! SKIP(FUNC|BREAK|CONT) occur when * a dotcmd is in a loop or a function body and appropriate * built-ins occurs in file scope in the sourced file. Values * other than SKIPFILE are reset by the appropriate eval*() * that contained the dotcmd() call. */ skip = current_skipstate(); if (skip != SKIPNONE) { if (skip == SKIPFILE) stop_skipping(); break; } } popstackmark(&smark); } /* * Read /etc/profile or .profile. Return on error. */ STATIC void read_profile(const char *name) { int fd; int xflag_set = 0; int vflag_set = 0; if (*name == '\0') return; INTOFF; if ((fd = open(name, O_RDONLY)) >= 0) setinputfd(fd, 1); INTON; if (fd < 0) return; /* -q turns off -x and -v just when executing init files */ if (qflag) { if (xflag) xflag = 0, xflag_set = 1; if (vflag) vflag = 0, vflag_set = 1; } (void)set_dot_funcnest(1); /* allow profile to "return" */ cmdloop(0); (void)set_dot_funcnest(0); if (qflag) { if (xflag_set) xflag = 1; if (vflag_set) vflag = 1; } popfile(); } /* * Read a file containing shell functions. */ void readcmdfile(char *name) { int fd; INTOFF; if ((fd = open(name, O_RDONLY)) >= 0) setinputfd(fd, 1); else error("Can't open %s", name); INTON; cmdloop(0); popfile(); } int exitcmd(int argc, char **argv) { if (stoppedjobs()) return 0; if (argc > 1) exitshell(number(argv[1])); else exitshell_savedstatus(); /* NOTREACHED */ }