/* $NetBSD: exec.c,v 1.30 2016/03/16 22:25:05 christos Exp $ */ /*- * Copyright (c) 1980, 1991, 1993 * The Regents of the University of California. All rights reserved. * * 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 #if 0 static char sccsid[] = "@(#)exec.c 8.3 (Berkeley) 5/23/95"; #else __RCSID("$NetBSD: exec.c,v 1.30 2016/03/16 22:25:05 christos Exp $"); #endif #endif /* not lint */ #include #include #include #include #include #include #include #include #include #include #include "csh.h" #include "extern.h" /* * System level search and execute of a command. We look in each directory * for the specified command name. If the name contains a '/' then we * execute only the full path name. If there is no search path then we * execute only full path names. */ extern char **environ; /* * As we search for the command we note the first non-trivial error * message for presentation to the user. This allows us often * to show that a file has the wrong mode/no access when the file * is not in the last component of the search path, so we must * go on after first detecting the error. */ static const char *exerr; /* Execution error message */ static Char *expath; /* Path for exerr */ /* * Xhash is an array of HSHSIZ bits (HSHSIZ / 8 chars), which are used * to hash execs. If it is allocated (havhash true), then to tell * whether ``name'' is (possibly) present in the i'th component * of the variable path, you look at the bit in xhash indexed by * hash(hashname("name"), i). This is setup automatically * after .login is executed, and recomputed whenever ``path'' is * changed. * The two part hash function is designed to let texec() call the * more expensive hashname() only once and the simple hash() several * times (once for each path component checked). * Byte size is assumed to be 8. */ #define HSHSIZ 8192 /* 1k bytes */ #define HSHMASK (HSHSIZ - 1) #define HSHMUL 243 static unsigned char xhash[HSHSIZ / 8]; #define hash(a, b) (((a) * HSHMUL + (b)) & HSHMASK) #define bit(h, b) ((h)[(b) >> 3] & 1 << ((b) & 7)) /* bit test */ #define bis(h, b) ((h)[(b) >> 3] = \ (unsigned char)((1 << ((b) & 7)) | (h)[(b) >> 3]))/* bit set */ static int hits, misses; /* Dummy search path for just absolute search when no path */ static Char *justabs[] = {STRNULL, 0}; static void pexerr(void) __dead; static void texec(Char *, Char **); static int hashname(Char *); static int tellmewhat(struct wordent *, Char *); static int executable(Char *, Char *, int); static int iscommand(Char *); void /*ARGSUSED*/ doexec(Char **v, struct command *t) { struct varent *pathv; Char *blk[2], **av, *dp, **pv, *sav; int i, hashval, hashval1; sigset_t nsigset; int slash; hashval = 0; /* * Glob the command name. We will search $path even if this does something, * as in sh but not in csh. One special case: if there is no PATH, then we * execute only commands which start with '/'. */ blk[0] = t->t_dcom[0]; blk[1] = 0; gflag = 0, tglob(blk); if (gflag) { pv = globall(blk); if (pv == 0) { setname(vis_str(blk[0])); stderror(ERR_NAME | ERR_NOMATCH); } gargv = 0; } else pv = saveblk(blk); trim(pv); exerr = 0; expath = Strsave(pv[0]); Vexpath = expath; pathv = adrof(STRpath); if (pathv == 0 && expath[0] != '/') { blkfree(pv); pexerr(); } slash = any(short2str(expath), '/'); /* * Glob the argument list, if necessary. Otherwise trim off the quote bits. */ gflag = 0; av = &t->t_dcom[1]; tglob(av); if (gflag) { av = globall(av); if (av == 0) { blkfree(pv); setname(vis_str(expath)); stderror(ERR_NAME | ERR_NOMATCH); } gargv = 0; } else av = saveblk(av); blkfree(t->t_dcom); t->t_dcom = blkspl(pv, av); xfree((ptr_t) pv); xfree((ptr_t) av); av = t->t_dcom; trim(av); if (*av == NULL || **av == '\0') pexerr(); xechoit(av); /* Echo command if -x */ /* * Since all internal file descriptors are set to close on exec, we don't * need to close them explicitly here. Just reorient ourselves for error * messages. */ SHIN = 0; SHOUT = 1; SHERR = 2; OLDSTD = 0; /* * We must do this AFTER any possible forking (like `foo` in glob) so that * this shell can still do subprocesses. */ sigemptyset(&nsigset); (void)sigprocmask(SIG_SETMASK, &nsigset, NULL); /* * If no path, no words in path, or a / in the filename then restrict the * command search. */ if (pathv == 0 || pathv->vec[0] == 0 || slash) pv = justabs; else pv = pathv->vec; sav = Strspl(STRslash, *av); /* / command name for postpending */ Vsav = sav; if (havhash) hashval = hashname(*av); i = 0; hits++; do { /* * Try to save time by looking at the hash table for where this command * could be. If we are doing delayed hashing, then we put the names in * one at a time, as the user enters them. This is kinda like Korn * Shell's "tracked aliases". */ if (!slash && pv[0][0] == '/' && havhash) { hashval1 = hash(hashval, i); if (!bit(xhash, hashval1)) goto cont; } if (pv[0][0] == 0 || eq(pv[0], STRdot)) /* don't make ./xxx */ texec(*av, av); else { dp = Strspl(*pv, sav); Vdp = dp; texec(dp, av); Vdp = 0; xfree((ptr_t)dp); } misses++; cont: pv++; i++; } while (*pv); hits--; Vsav = 0; xfree((ptr_t)sav); pexerr(); /* NOTREACHED */ } static void pexerr(void) { /* Couldn't find the damn thing */ if (expath) { setname(vis_str(expath)); Vexpath = 0; xfree((ptr_t)expath); expath = 0; } else setname(""); if (exerr) stderror(ERR_NAME | ERR_STRING, exerr); else stderror(ERR_NAME | ERR_COMMAND); /* NOTREACHED */ } /* * Execute command f, arg list t. * Record error message if not found. * Also do shell scripts here. */ static void texec(Char *sf, Char **st) { struct varent *v; Char *lastsh[2], **vp, *st0, **ost; char *f, **t; int fd; unsigned char c = '\0'; /* The order for the conversions is significant */ t = short2blk(st); f = short2str(sf); Vt = t; errno = 0; /* don't use a previous error */ (void)execve(f, t, environ); Vt = 0; blkfree((Char **)t); switch (errno) { case ENOEXEC: /* * From: casper@fwi.uva.nl (Casper H.S. Dik) If we could not execute * it, don't feed it to the shell if it looks like a binary! */ if ((fd = open(f, O_RDONLY)) != -1) { if (read(fd, (char *)&c, 1) == 1) { if (!Isprint(c) && (c != '\n' && c != '\t')) { (void)close(fd); /* * We *know* what ENOEXEC means. */ stderror(ERR_ARCH, f, strerror(errno)); } } #ifdef _PATH_BSHELL else c = '#'; #endif (void)close(fd); } /* * If there is an alias for shell, then put the words of the alias in * front of the argument list replacing the command name. Note no * interpretation of the words at this point. */ v = adrof1(STRshell, &aliases); if (v == 0) { vp = lastsh; vp[0] = adrof(STRshell) ? value(STRshell) : STR_SHELLPATH; vp[1] = NULL; #ifdef _PATH_BSHELL if (fd != -1 && c != '#') vp[0] = STR_BSHELL; #endif } else vp = v->vec; st0 = st[0]; st[0] = sf; ost = st; st = blkspl(vp, st); /* Splice up the new arglst */ ost[0] = st0; sf = *st; /* The order for the conversions is significant */ t = short2blk(st); f = short2str(sf); xfree((ptr_t) st); Vt = t; (void)execve(f, t, environ); Vt = 0; blkfree((Char **) t); /* FALLTHROUGH */ case ENOMEM: stderror(ERR_SYSTEM, f, strerror(errno)); /* NOTREACHED */ case ENOENT: break; default: if (exerr == 0) { exerr = strerror(errno); if (expath) xfree((ptr_t) expath); expath = Strsave(sf); Vexpath = expath; } } } /*ARGSUSED*/ void execash(Char **t, struct command *kp) { jmp_buf osetexit; sig_t osigint, osigquit, osigterm; int my_reenter, odidfds, oOLDSTD, oSHERR, oSHIN, oSHOUT; int saveDIAG, saveIN, saveOUT, saveSTD; if (chkstop == 0 && setintr) panystop(0); /* * Hmm, we don't really want to do that now because we might * fail, but what is the choice */ rechist(); osigint = signal(SIGINT, parintr); osigquit = signal(SIGQUIT, parintr); osigterm = signal(SIGTERM, parterm); odidfds = didfds; oSHIN = SHIN; oSHOUT = SHOUT; oSHERR = SHERR; oOLDSTD = OLDSTD; saveIN = dcopy(SHIN, -1); saveOUT = dcopy(SHOUT, -1); saveDIAG = dcopy(SHERR, -1); saveSTD = dcopy(OLDSTD, -1); lshift(kp->t_dcom, 1); getexit(osetexit); if ((my_reenter = setexit()) == 0) { SHIN = dcopy(0, -1); SHOUT = dcopy(1, -1); SHERR = dcopy(2, -1); didfds = 0; doexec(t, kp); } (void)signal(SIGINT, osigint); (void)signal(SIGQUIT, osigquit); (void)signal(SIGTERM, osigterm); doneinp = 0; didfds = odidfds; (void)close(SHIN); (void)close(SHOUT); (void)close(SHERR); (void)close(OLDSTD); SHIN = dmove(saveIN, oSHIN); SHOUT = dmove(saveOUT, oSHOUT); SHERR = dmove(saveDIAG, oSHERR); OLDSTD = dmove(saveSTD, oOLDSTD); resexit(osetexit); if (my_reenter) stderror(ERR_SILENT); } void xechoit(Char **t) { if (adrof(STRecho)) { int odidfds = didfds; (void)fflush(csherr); odidfds = didfds; didfds = 0; blkpr(csherr, t); (void)fputc('\n', csherr); (void)fflush(csherr); didfds = odidfds; } } void /*ARGSUSED*/ dohash(Char **v, struct command *t) { struct dirent *dp; struct varent *pathv; DIR *dirp; Char **pv; size_t cnt; int hashval, i; i = 0; havhash = 1; pathv = adrof(STRpath); for (cnt = 0; cnt < sizeof xhash; cnt++) xhash[cnt] = 0; if (pathv == 0) return; for (pv = pathv->vec; *pv; pv++, i++) { if (pv[0][0] != '/') continue; dirp = opendir(short2str(*pv)); if (dirp == NULL) continue; while ((dp = readdir(dirp)) != NULL) { if (dp->d_ino == 0) continue; if (dp->d_name[0] == '.' && (dp->d_name[1] == '\0' || (dp->d_name[1] == '.' && dp->d_name[2] == '\0'))) continue; hashval = hash(hashname(str2short(dp->d_name)), i); bis(xhash, hashval); /* tw_add_comm_name (dp->d_name); */ } (void) closedir(dirp); } } void /*ARGSUSED*/ dounhash(Char **v, struct command *t) { havhash = 0; } void /*ARGSUSED*/ hashstat(Char **v, struct command *t) { if (hits + misses) (void)fprintf(cshout, "%d hits, %d misses, %d%%\n", hits, misses, 100 * hits / (hits + misses)); } /* * Hash a command name. */ static int hashname(Char *cp) { long h = 0; while (*cp) h = hash(h, *cp++); return ((int) h); } static int iscommand(Char *name) { struct varent *v; Char **pv, *sav; int hashval, hashval1, i; int slash; hashval = 0; slash = any(short2str(name), '/'); v = adrof(STRpath); if (v == 0 || v->vec[0] == 0 || slash) pv = justabs; else pv = v->vec; sav = Strspl(STRslash, name); /* / command name for postpending */ if (havhash) hashval = hashname(name); i = 0; do { if (!slash && pv[0][0] == '/' && havhash) { hashval1 = hash(hashval, i); if (!bit(xhash, hashval1)) goto cont; } if (pv[0][0] == 0 || eq(pv[0], STRdot)) { /* don't make ./xxx */ if (executable(NULL, name, 0)) { xfree((ptr_t) sav); return i + 1; } } else { if (executable(*pv, sav, 0)) { xfree((ptr_t) sav); return i + 1; } } cont: pv++; i++; } while (*pv); xfree((ptr_t) sav); return 0; } /* Also by: * Andreas Luik * I S A GmbH - Informationssysteme fuer computerintegrierte Automatisierung * Azenberstr. 35 * D-7000 Stuttgart 1 * West-Germany * is the executable() routine below and changes to iscommand(). * Thanks again!! */ /* * executable() examines the pathname obtained by concatenating dir and name * (dir may be NULL), and returns 1 either if it is executable by us, or * if dir_ok is set and the pathname refers to a directory. * This is a bit kludgy, but in the name of optimization... */ static int executable(Char *dir, Char *name, int dir_ok) { struct stat stbuf; Char path[MAXPATHLEN + 1], *dp, *sp; char *strname; if (dir && *dir) { for (dp = path, sp = dir; *sp; *dp++ = *sp++) if (dp == &path[MAXPATHLEN + 1]) { *--dp = '\0'; break; } for (sp = name; *sp; *dp++ = *sp++) if (dp == &path[MAXPATHLEN + 1]) { *--dp = '\0'; break; } *dp = '\0'; strname = short2str(path); } else strname = short2str(name); return (stat(strname, &stbuf) != -1 && ((S_ISREG(stbuf.st_mode) && /* save time by not calling access() in the hopeless case */ (stbuf.st_mode & (S_IXOTH | S_IXGRP | S_IXUSR)) && access(strname, X_OK) == 0) || (dir_ok && S_ISDIR(stbuf.st_mode)))); } /* The dowhich() is by: * Andreas Luik * I S A GmbH - Informationssysteme fuer computerintegrierte Automatisierung * Azenberstr. 35 * D-7000 Stuttgart 1 * West-Germany * Thanks!! */ /*ARGSUSED*/ void dowhich(Char **v, struct command *c) { struct wordent lexw[3]; struct varent *vp; lexw[0].next = &lexw[1]; lexw[1].next = &lexw[2]; lexw[2].next = &lexw[0]; lexw[0].prev = &lexw[2]; lexw[1].prev = &lexw[0]; lexw[2].prev = &lexw[1]; lexw[0].word = STRNULL; lexw[2].word = STRret; while (*++v) { if ((vp = adrof1(*v, &aliases)) != NULL) { (void)fprintf(cshout, "%s: \t aliased to ", vis_str(*v)); blkpr(cshout, vp->vec); (void)fputc('\n', cshout); set(STRstatus, Strsave(STR0)); } else { lexw[1].word = *v; set(STRstatus, Strsave(tellmewhat(lexw, NULL) ? STR0 : STR1)); } } } static int tellmewhat(struct wordent *lexp, Char *str) { struct biltins *bptr; struct wordent *sp; Char *cmd, *s0, *s1, *s2; int i; int aliased, found; Char qc; aliased = 0; sp = lexp->next; if (adrof1(sp->word, &aliases)) { alias(lexp); sp = lexp->next; aliased = 1; } s0 = sp->word; /* to get the memory freeing right... */ /* handle quoted alias hack */ if ((*(sp->word) & (QUOTE | TRIM)) == QUOTE) (sp->word)++; /* do quoting, if it hasn't been done */ s1 = s2 = sp->word; while (*s2) switch (*s2) { case '\'': case '"': qc = *s2++; while (*s2 && *s2 != qc) *s1++ = (Char)(*s2++ | QUOTE); if (*s2) s2++; break; case '\\': if (*++s2) *s1++ = (Char)(*s2++ | QUOTE); break; default: *s1++ = *s2++; } *s1 = '\0'; for (bptr = bfunc; bptr < &bfunc[nbfunc]; bptr++) { if (eq(sp->word, str2short(bptr->bname))) { if (str == NULL) { if (aliased) prlex(cshout, lexp); (void)fprintf(cshout, "%s: shell built-in command.\n", vis_str(sp->word)); } else (void)Strcpy(str, sp->word); sp->word = s0; /* we save and then restore this */ return 1; } } sp->word = cmd = globone(sp->word, G_IGNORE); if ((i = iscommand(sp->word)) != 0) { Char **pv; struct varent *v; int slash = any(short2str(sp->word), '/'); v = adrof(STRpath); if (v == 0 || v->vec[0] == 0 || slash) pv = justabs; else pv = v->vec; while (--i) pv++; if (pv[0][0] == 0 || eq(pv[0], STRdot)) { if (!slash) { sp->word = Strspl(STRdotsl, sp->word); prlex(cshout, lexp); xfree((ptr_t) sp->word); } else prlex(cshout, lexp); } else { s1 = Strspl(*pv, STRslash); sp->word = Strspl(s1, sp->word); xfree((ptr_t) s1); if (str == NULL) prlex(cshout, lexp); else (void)Strcpy(str, sp->word); xfree((ptr_t) sp->word); } found = 1; } else { if (str == NULL) { if (aliased) prlex(cshout, lexp); (void)fprintf(csherr, "%s: Command not found.\n", vis_str(sp->word)); } else (void)Strcpy(str, sp->word); found = 0; } sp->word = s0; /* we save and then restore this */ xfree((ptr_t) cmd); return found; }