/*- * Copyright (c) 1991 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. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by the University of * California, Berkeley and its contributors. * 4. 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. */ #ifndef lint static char sccsid[] = "@(#)expand.c 5.1 (Berkeley) 3/7/91"; #endif /* not lint */ /* * Routines to expand arguments to commands. We have to deal with * backquotes, shell variables, and file metacharacters. */ #include "shell.h" #include "main.h" #include "nodes.h" #include "eval.h" #include "expand.h" #include "syntax.h" #include "parser.h" #include "jobs.h" #include "options.h" #include "var.h" #include "input.h" #include "output.h" #include "memalloc.h" #include "error.h" #include "mystring.h" #include #include #include #include #if USEGETPW #include #endif /* * Structure specifying which parts of the string should be searched * for IFS characters. */ struct ifsregion { struct ifsregion *next; /* next region in list */ int begoff; /* offset of start of region */ int endoff; /* offset of end of region */ int nulonly; /* search for nul bytes only */ }; char *expdest; /* output of current string */ struct nodelist *argbackq; /* list of back quote expressions */ struct ifsregion ifsfirst; /* first struct in list of ifs regions */ struct ifsregion *ifslastp; /* last struct in list */ struct arglist exparg; /* holds expanded arg list */ #if UDIR || TILDE /* * Set if the last argument processed had /u/logname or ~logname expanded. * This variable is read by the cd command. */ int didudir; #endif #ifdef __STDC__ STATIC void argstr(char *, int); STATIC void expbackq(union node *, int, int); STATIC char *evalvar(char *, int); STATIC int varisset(int); STATIC void varvalue(int, int, int); STATIC void recordregion(int, int, int); STATIC void ifsbreakup(char *, struct arglist *); STATIC void expandmeta(struct strlist *); STATIC void expmeta(char *, char *); STATIC void addfname(char *); STATIC struct strlist *expsort(struct strlist *); STATIC struct strlist *msort(struct strlist *, int); STATIC int pmatch(char *, char *); #else STATIC void argstr(); STATIC void expbackq(); STATIC char *evalvar(); STATIC int varisset(); STATIC void varvalue(); STATIC void recordregion(); STATIC void ifsbreakup(); STATIC void expandmeta(); STATIC void expmeta(); STATIC void addfname(); STATIC struct strlist *expsort(); STATIC struct strlist *msort(); STATIC int pmatch(); #endif #if UDIR || TILDE #ifdef __STDC__ STATIC char *expudir(char *); #else STATIC char *expudir(); #endif #endif /* UDIR || TILDE */ /* * Expand shell variables and backquotes inside a here document. */ void expandhere(arg, fd) union node *arg; /* the document */ int fd; /* where to write the expanded version */ { herefd = fd; expandarg(arg, (struct arglist *)NULL, 0); xwrite(fd, stackblock(), expdest - stackblock()); } /* * Perform variable substitution and command substitution on an argument, * placing the resulting list of arguments in arglist. If full is true, * perform splitting and file name expansion. When arglist is NULL, perform * here document expansion. */ void expandarg(arg, arglist, full) union node *arg; struct arglist *arglist; { struct strlist *sp; char *p; #if UDIR || TILDE didudir = 0; #endif argbackq = arg->narg.backquote; STARTSTACKSTR(expdest); ifsfirst.next = NULL; ifslastp = NULL; argstr(arg->narg.text, full); if (arglist == NULL) return; /* here document expanded */ STPUTC('\0', expdest); p = grabstackstr(expdest); exparg.lastp = &exparg.list; if (full) { ifsbreakup(p, &exparg); *exparg.lastp = NULL; exparg.lastp = &exparg.list; expandmeta(exparg.list); } else { sp = (struct strlist *)stalloc(sizeof (struct strlist)); sp->text = p; *exparg.lastp = sp; exparg.lastp = &sp->next; } while (ifsfirst.next != NULL) { struct ifsregion *ifsp; INTOFF; ifsp = ifsfirst.next->next; ckfree(ifsfirst.next); ifsfirst.next = ifsp; INTON; } *exparg.lastp = NULL; if (exparg.list) { *arglist->lastp = exparg.list; arglist->lastp = exparg.lastp; } } /* * Perform variable and command substitution. If full is set, output CTLESC * characters to allow for further processing. If full is not set, treat * $@ like $* since no splitting will be performed. */ STATIC void argstr(p, full) register char *p; { char c; for (;;) { switch (c = *p++) { case '\0': case CTLENDVAR: goto breakloop; case CTLESC: if (full) STPUTC(c, expdest); c = *p++; STPUTC(c, expdest); break; case CTLVAR: p = evalvar(p, full); break; case CTLBACKQ: case CTLBACKQ|CTLQUOTE: expbackq(argbackq->n, c & CTLQUOTE, full); argbackq = argbackq->next; break; default: STPUTC(c, expdest); } } breakloop:; } /* * Expand stuff in backwards quotes. */ STATIC void expbackq(cmd, quoted, full) union node *cmd; { struct backcmd in; int i; char buf[128]; char *p; char *dest = expdest; struct ifsregion saveifs, *savelastp; struct nodelist *saveargbackq; char lastc; int startloc = dest - stackblock(); char const *syntax = quoted? DQSYNTAX : BASESYNTAX; int saveherefd; INTOFF; saveifs = ifsfirst; savelastp = ifslastp; saveargbackq = argbackq; saveherefd = herefd; herefd = -1; p = grabstackstr(dest); evalbackcmd(cmd, &in); ungrabstackstr(p, dest); ifsfirst = saveifs; ifslastp = savelastp; argbackq = saveargbackq; herefd = saveherefd; p = in.buf; lastc = '\0'; for (;;) { if (--in.nleft < 0) { if (in.fd < 0) break; while ((i = read(in.fd, buf, sizeof buf)) < 0 && errno == EINTR); TRACE(("expbackq: read returns %d\n", i)); if (i <= 0) break; p = buf; in.nleft = i - 1; } lastc = *p++; if (lastc != '\0') { if (full && syntax[lastc] == CCTL) STPUTC(CTLESC, dest); STPUTC(lastc, dest); } } if (lastc == '\n') { STUNPUTC(dest); } if (in.fd >= 0) close(in.fd); if (in.buf) ckfree(in.buf); if (in.jp) exitstatus = waitforjob(in.jp); if (quoted == 0) recordregion(startloc, dest - stackblock(), 0); TRACE(("evalbackq: size=%d: \"%.*s\"\n", (dest - stackblock()) - startloc, (dest - stackblock()) - startloc, stackblock() + startloc)); expdest = dest; INTON; } /* * Expand a variable, and return a pointer to the next character in the * input string. */ STATIC char * evalvar(p, full) char *p; { int subtype; int flags; char *var; char *val; int c; int set; int special; int startloc; flags = *p++; subtype = flags & VSTYPE; var = p; special = 0; if (! is_name(*p)) special = 1; p = strchr(p, '=') + 1; again: /* jump here after setting a variable with ${var=text} */ if (special) { set = varisset(*var); val = NULL; } else { val = lookupvar(var); if (val == NULL || (flags & VSNUL) && val[0] == '\0') { val = NULL; set = 0; } else set = 1; } startloc = expdest - stackblock(); if (set && subtype != VSPLUS) { /* insert the value of the variable */ if (special) { varvalue(*var, flags & VSQUOTE, full); } else { char const *syntax = (flags & VSQUOTE)? DQSYNTAX : BASESYNTAX; while (*val) { if (full && syntax[*val] == CCTL) STPUTC(CTLESC, expdest); STPUTC(*val++, expdest); } } } if (subtype == VSPLUS) set = ! set; if (((flags & VSQUOTE) == 0 || (*var == '@' && shellparam.nparam != 1)) && (set || subtype == VSNORMAL)) recordregion(startloc, expdest - stackblock(), flags & VSQUOTE); if (! set && subtype != VSNORMAL) { if (subtype == VSPLUS || subtype == VSMINUS) { argstr(p, full); } else { char *startp; int saveherefd = herefd; herefd = -1; argstr(p, 0); STACKSTRNUL(expdest); herefd = saveherefd; startp = stackblock() + startloc; if (subtype == VSASSIGN) { setvar(var, startp, 0); STADJUST(startp - expdest, expdest); flags &=~ VSNUL; goto again; } /* subtype == VSQUESTION */ if (*p != CTLENDVAR) { outfmt(&errout, "%s\n", startp); error((char *)NULL); } error("%.*s: parameter %snot set", p - var - 1, var, (flags & VSNUL)? "null or " : nullstr); } } if (subtype != VSNORMAL) { /* skip to end of alternative */ int nesting = 1; for (;;) { if ((c = *p++) == CTLESC) p++; else if (c == CTLBACKQ || c == (CTLBACKQ|CTLQUOTE)) { if (set) { if (argbackq != NULL) argbackq = argbackq->next; } } else if (c == CTLVAR) { if ((*p++ & VSTYPE) != VSNORMAL) nesting++; } else if (c == CTLENDVAR) { if (--nesting == 0) break; } } } return p; } /* * Test whether a specialized variable is set. */ STATIC int varisset(name) char name; { char **ap; if (name == '!') { if (backgndpid == -1) return 0; } else if (name == '@' || name == '*') { if (*shellparam.p == NULL) return 0; } else if ((unsigned)(name -= '1') <= '9' - '1') { ap = shellparam.p; do { if (*ap++ == NULL) return 0; } while (--name >= 0); } return 1; } /* * Add the value of a specialized variable to the stack string. */ STATIC void varvalue(name, quoted, allow_split) char name; { int num; char temp[32]; char *p; int i; extern int oexitstatus; char sep; char **ap; char const *syntax; switch (name) { case '$': num = rootpid; goto numvar; case '?': num = oexitstatus; goto numvar; case '#': num = shellparam.nparam; goto numvar; case '!': num = backgndpid; numvar: p = temp + 31; temp[31] = '\0'; do { *--p = num % 10 + '0'; } while ((num /= 10) != 0); while (*p) STPUTC(*p++, expdest); break; case '-': for (i = 0 ; optchar[i] ; i++) { if (optval[i]) STPUTC(optchar[i], expdest); } break; case '@': if (allow_split) { sep = '\0'; goto allargs; } /* fall through */ case '*': sep = ' '; allargs: /* Only emit CTLESC if we will do further processing, i.e. if allow_split is set. */ syntax = quoted && allow_split ? DQSYNTAX : BASESYNTAX; for (ap = shellparam.p ; (p = *ap++) != NULL ; ) { /* should insert CTLESC characters */ while (*p) { if (syntax[*p] == CCTL) STPUTC(CTLESC, expdest); STPUTC(*p++, expdest); } if (*ap) STPUTC(sep, expdest); } break; case '0': p = arg0; string: /* Only emit CTLESC if we will do further processing, i.e. if allow_split is set. */ syntax = quoted && allow_split ? DQSYNTAX : BASESYNTAX; while (*p) { if (syntax[*p] == CCTL) STPUTC(CTLESC, expdest); STPUTC(*p++, expdest); } break; default: if ((unsigned)(name -= '1') <= '9' - '1') { p = shellparam.p[name]; goto string; } break; } } /* * Record the the fact that we have to scan this region of the * string for IFS characters. */ STATIC void recordregion(start, end, nulonly) { register struct ifsregion *ifsp; if (ifslastp == NULL) { ifsp = &ifsfirst; } else { ifsp = (struct ifsregion *)ckmalloc(sizeof (struct ifsregion)); ifslastp->next = ifsp; } ifslastp = ifsp; ifslastp->next = NULL; ifslastp->begoff = start; ifslastp->endoff = end; ifslastp->nulonly = nulonly; } /* * Break the argument string into pieces based upon IFS and add the * strings to the argument list. The regions of the string to be * searched for IFS characters have been stored by recordregion. */ STATIC void ifsbreakup(string, arglist) char *string; struct arglist *arglist; { struct ifsregion *ifsp; struct strlist *sp; char *start; register char *p; char *q; char *ifs; start = string; if (ifslastp != NULL) { ifsp = &ifsfirst; do { p = string + ifsp->begoff; ifs = ifsp->nulonly? nullstr : ifsval(); while (p < string + ifsp->endoff) { q = p; if (*p == CTLESC) p++; if (strchr(ifs, *p++)) { if (q > start || *ifs != ' ') { *q = '\0'; sp = (struct strlist *)stalloc(sizeof *sp); sp->text = start; *arglist->lastp = sp; arglist->lastp = &sp->next; } if (*ifs == ' ') { for (;;) { if (p >= string + ifsp->endoff) break; q = p; if (*p == CTLESC) p++; if (strchr(ifs, *p++) == NULL) { p = q; break; } } } start = p; } } } while ((ifsp = ifsp->next) != NULL); if (*start || (*ifs != ' ' && start > string)) { sp = (struct strlist *)stalloc(sizeof *sp); sp->text = start; *arglist->lastp = sp; arglist->lastp = &sp->next; } } else { sp = (struct strlist *)stalloc(sizeof *sp); sp->text = start; *arglist->lastp = sp; arglist->lastp = &sp->next; } } /* * Expand shell metacharacters. At this point, the only control characters * should be escapes. The results are stored in the list exparg. */ char *expdir; STATIC void expandmeta(str) struct strlist *str; { char *p; struct strlist **savelastp; struct strlist *sp; char c; while (str) { if (fflag) goto nometa; p = str->text; #if UDIR if (p[0] == '/' && p[1] == 'u' && p[2] == '/') str->text = p = expudir(p); #endif #if TILDE if (p[0] == '~') str->text = p = expudir(p); #endif for (;;) { /* fast check for meta chars */ if ((c = *p++) == '\0') goto nometa; if (c == '*' || c == '?' || c == '[' || c == '!') break; } savelastp = exparg.lastp; INTOFF; if (expdir == NULL) { int i = strlen(str->text); expdir = ckmalloc(i < 2048 ? 2048 : i); /* XXX */ } expmeta(expdir, str->text); ckfree(expdir); expdir = NULL; INTON; if (exparg.lastp == savelastp) { if (! zflag) { nometa: *exparg.lastp = str; rmescapes(str->text); exparg.lastp = &str->next; } } else { *exparg.lastp = NULL; *savelastp = sp = expsort(*savelastp); while (sp->next != NULL) sp = sp->next; exparg.lastp = &sp->next; } str = str->next; } } #if UDIR || TILDE /* * UDIR: Expand /u/username into the home directory for the specified user. * TILDE: Expand ~username into the home directory for the specified user. * We hope not to use the getpw stuff here, because then we would have to load * in stdio and who knows what else. With networked password files there is * no choice alas. */ #define MAXLOGNAME 32 #define MAXPWLINE 128 char *pfgets(); STATIC char * expudir(path) char *path; { register char *p, *q, *r; char name[MAXLOGNAME]; char line[MAXPWLINE]; int i; #if USEGETPW struct passwd *pw; #endif r = path; /* result on failure */ p = r + (*r == '~' ? 1 : 3); /* the 1 skips "~", 3 skips "/u/" */ q = name; while (*p && *p != '/') { if (q >= name + MAXLOGNAME - 1) return r; /* fail, name too long */ *q++ = *p++; } *q = '\0'; #if TILDE if (*name == 0 && *r == '~') { /* null name, use $HOME */ if ((q = lookupvar("HOME")) == NULL) return r; /* fail, home not set */ i = strlen(q); r = stalloc(i + strlen(p) + 1); scopy(q, r); scopy(p, r + i); TRACE(("expudir converts %s to %s\n", path, r)); didudir = 1; path = r; return r; } #endif #if !USEGETPW /* can do without the bloat */ setinputfile("/etc/passwd", 1); q = line + strlen(name); while (pfgets(line, MAXPWLINE) != NULL) { if (line[0] == name[0] && prefix(name, line) && *q == ':') { /* skip to start of home directory */ i = 4; do { while (*++q && *q != ':'); } while (--i > 0); if (*q == '\0') break; /* fail, corrupted /etc/passwd */ q++; for (r = q ; *r && *r != '\n' && *r != ':' ; r++); *r = '\0'; /* nul terminate home directory */ i = r - q; /* i = strlen(q) */ r = stalloc(i + strlen(p) + 1); scopy(q, r); scopy(p, r + i); TRACE(("expudir converts %s to %s\n", path, r)); didudir = 1; path = r; /* succeed */ break; } } popfile(); #else if ((pw = getpwnam(name)) != NULL) { /* user exists */ q = pw->pw_dir; i = strlen(q); r = stalloc(i + strlen(p) + 1); scopy(q, r); scopy(p, r + i); TRACE(("expudir converts %s to %s\n", path, r)); didudir = 1; path = r; } endpwent(); #endif /* USEGETPW */ return r; } #endif /* * Do metacharacter (i.e. *, ?, [...]) expansion. */ STATIC void expmeta(enddir, name) char *enddir; char *name; { register char *p; char *q; char *start; char *endname; int metaflag; struct stat statb; DIR *dirp; struct dirent *dp; int atend; int matchdot; metaflag = 0; start = name; for (p = name ; ; p++) { if (*p == '*' || *p == '?') metaflag = 1; else if (*p == '[') { q = p + 1; if (*q == '!') q++; for (;;) { if (*q == CTLESC) q++; if (*q == '/' || *q == '\0') break; if (*++q == ']') { metaflag = 1; break; } } } else if (*p == '!' && p[1] == '!' && (p == name || p[-1] == '/')) { metaflag = 1; } else if (*p == '\0') break; else if (*p == CTLESC) p++; if (*p == '/') { if (metaflag) break; start = p + 1; } } if (metaflag == 0) { /* we've reached the end of the file name */ if (enddir != expdir) metaflag++; for (p = name ; ; p++) { if (*p == CTLESC) p++; *enddir++ = *p; if (*p == '\0') break; } if (metaflag == 0 || stat(expdir, &statb) >= 0) addfname(expdir); return; } endname = p; if (start != name) { p = name; while (p < start) { if (*p == CTLESC) p++; *enddir++ = *p++; } } if (enddir == expdir) { p = "."; } else if (enddir == expdir + 1 && *expdir == '/') { p = "/"; } else { p = expdir; enddir[-1] = '\0'; } if ((dirp = opendir(p)) == NULL) return; if (enddir != expdir) enddir[-1] = '/'; if (*endname == 0) { atend = 1; } else { atend = 0; *endname++ = '\0'; } matchdot = 0; if (start[0] == '.' || start[0] == CTLESC && start[1] == '.') matchdot++; while (! int_pending() && (dp = readdir(dirp)) != NULL) { if (dp->d_name[0] == '.' && ! matchdot) continue; if (patmatch(start, dp->d_name)) { if (atend) { scopy(dp->d_name, enddir); addfname(expdir); } else { char *q; for (p = enddir, q = dp->d_name ; *p++ = *q++ ;); p[-1] = '/'; expmeta(p, endname); } } } closedir(dirp); if (! atend) endname[-1] = '/'; } /* * Add a file name to the list. */ STATIC void addfname(name) char *name; { char *p; struct strlist *sp; p = stalloc(strlen(name) + 1); scopy(name, p); sp = (struct strlist *)stalloc(sizeof *sp); sp->text = p; *exparg.lastp = sp; exparg.lastp = &sp->next; } /* * Sort the results of file name expansion. It calculates the number of * strings to sort and then calls msort (short for merge sort) to do the * work. */ STATIC struct strlist * expsort(str) struct strlist *str; { int len; struct strlist *sp; len = 0; for (sp = str ; sp ; sp = sp->next) len++; return msort(str, len); } STATIC struct strlist * msort(list, len) struct strlist *list; { struct strlist *p, *q; struct strlist **lpp; int half; int n; if (len <= 1) return list; half = len >> 1; p = list; for (n = half ; --n >= 0 ; ) { q = p; p = p->next; } q->next = NULL; /* terminate first half of list */ q = msort(list, half); /* sort first half of list */ p = msort(p, len - half); /* sort second half */ lpp = &list; for (;;) { if (strcmp(p->text, q->text) < 0) { *lpp = p; lpp = &p->next; if ((p = *lpp) == NULL) { *lpp = q; break; } } else { *lpp = q; lpp = &q->next; if ((q = *lpp) == NULL) { *lpp = p; break; } } } return list; } /* * Returns true if the pattern matches the string. */ int patmatch(pattern, string) char *pattern; char *string; { if (pattern[0] == '!' && pattern[1] == '!') return 1 - pmatch(pattern + 2, string); else return pmatch(pattern, string); } STATIC int pmatch(pattern, string) char *pattern; char *string; { register char *p, *q; register char c; p = pattern; q = string; for (;;) { switch (c = *p++) { case '\0': goto breakloop; case CTLESC: if (*q++ != *p++) return 0; break; case '?': if (*q++ == '\0') return 0; break; case '*': c = *p; if (c != CTLESC && c != '?' && c != '*' && c != '[') { while (*q != c) { if (*q == '\0') return 0; q++; } } do { if (pmatch(p, q)) return 1; } while (*q++ != '\0'); return 0; case '[': { char *endp; int invert, found; char chr; endp = p; if (*endp == '!') endp++; for (;;) { if (*endp == '\0') goto dft; /* no matching ] */ if (*endp == CTLESC) endp++; if (*++endp == ']') break; } invert = 0; if (*p == '!') { invert++; p++; } found = 0; chr = *q++; c = *p++; do { if (c == CTLESC) c = *p++; if (*p == '-' && p[1] != ']') { p++; if (*p == CTLESC) p++; if (chr >= c && chr <= *p) found = 1; p++; } else { if (chr == c) found = 1; } } while ((c = *p++) != ']'); if (found == invert) return 0; break; } dft: default: if (*q++ != c) return 0; break; } } breakloop: if (*q != '\0') return 0; return 1; } /* * Remove any CTLESC characters from a string. */ void rmescapes(str) char *str; { register char *p, *q; p = str; while (*p != CTLESC) { if (*p++ == '\0') return; } q = p; while (*p) { if (*p == CTLESC) p++; *q++ = *p++; } *q = '\0'; } /* * See if a pattern matches in a case statement. */ int casematch(pattern, val) union node *pattern; char *val; { struct stackmark smark; int result; char *p; setstackmark(&smark); argbackq = pattern->narg.backquote; STARTSTACKSTR(expdest); ifslastp = NULL; /* Preserve any CTLESC characters inserted previously, so that we won't expand reg exps which are inside strings. */ argstr(pattern->narg.text, 1); STPUTC('\0', expdest); p = grabstackstr(expdest); result = patmatch(p, val); popstackmark(&smark); return result; }