/* $NetBSD: input.c,v 1.71.2.1 2021/04/06 17:52:03 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 #if 0 static char sccsid[] = "@(#)input.c 8.3 (Berkeley) 6/9/95"; #else __RCSID("$NetBSD: input.c,v 1.71.2.1 2021/04/06 17:52:03 martin Exp $"); #endif #endif /* not lint */ #include /* defines BUFSIZ */ #include #include #include #include #include #include #include /* * This file implements the input routines used by the parser. */ #include "shell.h" #include "redir.h" #include "syntax.h" #include "input.h" #include "output.h" #include "options.h" #include "memalloc.h" #include "error.h" #include "alias.h" #include "parser.h" #include "myhistedit.h" #include "show.h" #define EOF_NLEFT -99 /* value of parsenleft when EOF pushed back */ MKINIT struct strpush { struct strpush *prev; /* preceding string on stack */ const char *prevstring; int prevnleft; int prevlleft; struct alias *ap; /* if push was associated with an alias */ }; /* * The parsefile structure pointed to by the global variable parsefile * contains information about the current file being read. */ MKINIT struct parsefile { struct parsefile *prev; /* preceding file on stack */ int linno; /* current line */ int fd; /* file descriptor (or -1 if string) */ int nleft; /* number of chars left in this line */ int lleft; /* number of chars left in this buffer */ int nskip; /* number of \0's dropped in previous line */ const char *nextc; /* next char in buffer */ char *buf; /* input buffer */ struct strpush *strpush; /* for pushing strings at this level */ struct strpush basestrpush; /* so pushing one is fast */ }; int plinno = 1; /* input line number */ int parsenleft; /* copy of parsefile->nleft */ MKINIT int parselleft; /* copy of parsefile->lleft */ const char *parsenextc; /* copy of parsefile->nextc */ MKINIT struct parsefile basepf; /* top level input file */ MKINIT char basebuf[BUFSIZ]; /* buffer for top level input file */ struct parsefile *parsefile = &basepf; /* current input file */ int init_editline = 0; /* editline library initialized? */ int whichprompt; /* 1 == PS1, 2 == PS2 */ STATIC void pushfile(void); static int preadfd(void); #ifdef mkinit INCLUDE INCLUDE "input.h" INCLUDE "error.h" INIT { basepf.nextc = basepf.buf = basebuf; } RESET { if (exception != EXSHELLPROC) parselleft = parsenleft = 0; /* clear input buffer */ popallfiles(); } SHELLPROC { popallfiles(); } #endif #if 0 /* this is unused */ /* * Read a line from the script. */ char * pfgets(char *line, int len) { char *p = line; int nleft = len; int c; while (--nleft > 0) { c = pgetc_macro(); if (c == PFAKE) /* consecutive PFAKEs is impossible */ c = pgetc_macro(); if (c == PEOF) { if (p == line) return NULL; break; } *p++ = c; if (c == '\n') { plinno++; break; } } *p = '\0'; return line; } #endif /* * Read a character from the script, returning PEOF on end of file. * Nul characters in the input are silently discarded. */ int pgetc(void) { int c; c = pgetc_macro(); if (c == PFAKE) c = pgetc_macro(); return c; } static int preadfd(void) { int nr; char *buf = parsefile->buf; parsenextc = buf; retry: #ifndef SMALL if (parsefile->fd == 0 && el) { static const char *rl_cp; static int el_len; if (rl_cp == NULL) rl_cp = el_gets(el, &el_len); if (rl_cp == NULL) nr = el_len == 0 ? 0 : -1; else { nr = el_len; if (nr > BUFSIZ - 8) nr = BUFSIZ - 8; memcpy(buf, rl_cp, nr); if (nr != el_len) { el_len -= nr; rl_cp += nr; } else rl_cp = 0; } } else #endif nr = read(parsefile->fd, buf, BUFSIZ - 8); if (nr <= 0) { if (nr < 0) { if (errno == EINTR) goto retry; if (parsefile->fd == 0 && errno == EWOULDBLOCK) { int flags = fcntl(0, F_GETFL, 0); if (flags >= 0 && flags & O_NONBLOCK) { flags &=~ O_NONBLOCK; if (fcntl(0, F_SETFL, flags) >= 0) { out2str("sh: turning off NDELAY mode\n"); goto retry; } } } } nr = -1; } return nr; } /* * Refill the input buffer and return the next input character: * * 1) If a string was pushed back on the input, pop it; * 2) If an EOF was pushed back (parsenleft == EOF_NLEFT) or we are reading * from a string so we can't refill the buffer, return EOF. * 3) If there is more stuff in this buffer, use it else call read to fill it. * 4) Process input up to the next newline, deleting nul characters. */ int preadbuffer(void) { char *p, *q; int more; #ifndef SMALL int something; #endif char savec; while (parsefile->strpush) { if (parsenleft == -1 && parsefile->strpush->ap != NULL) return PFAKE; popstring(); if (--parsenleft >= 0) return (*parsenextc++); } if (parsenleft == EOF_NLEFT || parsefile->buf == NULL) return PEOF; flushout(&output); flushout(&errout); again: if (parselleft <= 0) { if ((parselleft = preadfd()) == -1) { parselleft = parsenleft = EOF_NLEFT; return PEOF; } parsefile->nskip = 0; } /* jump over slots for any \0 chars that were dropped */ parsenextc += parsefile->nskip; parsefile->nskip = 0; /* p = (not const char *)parsenextc; */ p = parsefile->buf + (parsenextc - parsefile->buf); q = p; /* delete nul characters */ #ifndef SMALL something = 0; #endif for (more = 1; more;) { switch (*p) { case '\0': p++; /* Skip nul */ parsefile->nskip++; goto check; case '\t': case ' ': break; case '\n': parsenleft = q - parsenextc; more = 0; /* Stop processing here */ break; default: #ifndef SMALL something = 1; #endif break; } if (parsefile->nskip) *q++ = *p++; else q = ++p; check: if (--parselleft <= 0) { parsenleft = q - parsenextc - 1; if (parsenleft < 0) goto again; *q = '\0'; more = 0; } } savec = *q; *q = '\0'; #ifndef SMALL if (parsefile->fd == 0 && hist && (something || whichprompt == 2)) { HistEvent he; INTOFF; history(hist, &he, whichprompt != 2 ? H_ENTER : H_APPEND, parsenextc); INTON; } #endif if (vflag) { out2str(parsenextc); flushout(out2); } *q = savec; return *parsenextc++; } /* * Test whether we have reached EOF on input stream. * Return true only if certain (without attempting a read). * * Note the similarity to the opening section of preadbuffer() */ int at_eof(void) { struct strpush *sp = parsefile->strpush; if (parsenleft > 0) /* more chars are in the buffer */ return 0; while (sp != NULL) { /* * If any pushed string has any remaining data, * then we are not at EOF (simulating popstring()) */ if (sp->prevnleft > 0) return 0; sp = sp->prev; } /* * If we reached real EOF and pushed it back, * or if we are just processing a string (not reading a file) * then there is no more. Note that if a file pushes a * string, the file's ->buf remains present. */ if (parsenleft == EOF_NLEFT || parsefile->buf == NULL) return 1; /* * In other cases, there might be more */ return 0; } /* * Undo the last call to pgetc. Only one character may be pushed back. * PEOF may be pushed back. */ void pungetc(void) { parsenleft++; parsenextc--; } /* * Push a string back onto the input at this current parsefile level. * We handle aliases this way. */ void pushstring(const char *s, int len, struct alias *ap) { struct strpush *sp; VTRACE(DBG_INPUT, ("pushstring(\"%.*s\", %d)%s%s%s had: nl=%d ll=%d \"%.*s\"\n", len, s, len, ap ? " for alias:'" : "", ap ? ap->name : "", ap ? "'" : "", parsenleft, parselleft, parsenleft, parsenextc)); INTOFF; if (parsefile->strpush) { sp = ckmalloc(sizeof (struct strpush)); sp->prev = parsefile->strpush; parsefile->strpush = sp; } else sp = parsefile->strpush = &(parsefile->basestrpush); sp->prevstring = parsenextc; sp->prevnleft = parsenleft; sp->prevlleft = parselleft; sp->ap = ap; if (ap) ap->flag |= ALIASINUSE; parsenextc = s; parsenleft = len; INTON; } void popstring(void) { struct strpush *sp = parsefile->strpush; INTOFF; if (sp->ap) { int alen; if ((alen = strlen(sp->ap->val)) > 0 && (sp->ap->val[alen - 1] == ' ' || sp->ap->val[alen - 1] == '\t')) checkkwd |= CHKALIAS; sp->ap->flag &= ~ALIASINUSE; } parsenextc = sp->prevstring; parsenleft = sp->prevnleft; parselleft = sp->prevlleft; VTRACE(DBG_INPUT, ("popstring()%s%s%s nl=%d ll=%d \"%.*s\"\n", sp->ap ? " from alias:'" : "", sp->ap ? sp->ap->name : "", sp->ap ? "'" : "", parsenleft, parselleft, parsenleft, parsenextc)); parsefile->strpush = sp->prev; if (sp != &(parsefile->basestrpush)) ckfree(sp); INTON; } /* * Set the input to take input from a file. If push is set, push the * old input onto the stack first. */ void setinputfile(const char *fname, int push) { unsigned char magic[4]; int fd; int fd2; struct stat sb; CTRACE(DBG_INPUT,("setinputfile(\"%s\", %spush)\n",fname,push?"":"no")); INTOFF; if ((fd = open(fname, O_RDONLY)) < 0) error("Can't open %s", fname); /* Since the message "Syntax error: "(" unexpected" is not very * helpful, we check if the file starts with the ELF magic to * avoid that message. The first lseek tries to make sure that * we can later rewind the file. */ if (fstat(fd, &sb) == 0 && S_ISREG(sb.st_mode) && lseek(fd, 0, SEEK_SET) == 0) { if (read(fd, magic, 4) == 4) { if (memcmp(magic, "\177ELF", 4) == 0) { (void)close(fd); error("Cannot execute ELF binary %s", fname); } } if (lseek(fd, 0, SEEK_SET) != 0) { (void)close(fd); error("Cannot rewind the file %s", fname); } } fd2 = to_upper_fd(fd); /* closes fd, returns higher equiv */ if (fd2 == fd) { (void) close(fd); error("Out of file descriptors"); } setinputfd(fd2, push); INTON; } /* * When a shell fd needs to be altered (when the user wants to use * the same fd - rare, but happens - we need to locate the ref to * the fd, and update it. This happens via a callback. * This is the callback func for fd's used for shell input */ static void input_fd_swap(int from, int to) { struct parsefile *pf; pf = parsefile; while (pf != NULL) { /* don't need to stop at basepf */ if (pf->fd == from) pf->fd = to; pf = pf->prev; } } /* * Like setinputfile, but takes an open file descriptor. Call this with * interrupts off. */ void setinputfd(int fd, int push) { VTRACE(DBG_INPUT, ("setinputfd(%d, %spush)\n", fd, push?"":"no")); INTOFF; register_sh_fd(fd, input_fd_swap); (void) fcntl(fd, F_SETFD, FD_CLOEXEC); if (push) pushfile(); if (parsefile->fd > 0) sh_close(parsefile->fd); parsefile->fd = fd; if (parsefile->buf == NULL) parsefile->buf = ckmalloc(BUFSIZ); parselleft = parsenleft = 0; plinno = 1; INTON; CTRACE(DBG_INPUT, ("setinputfd(%d, %spush) done; plinno=1\n", fd, push ? "" : "no")); } /* * Like setinputfile, but takes input from a string. */ void setinputstring(char *string, int push, int line1) { INTOFF; if (push) /* XXX: always, as it happens */ pushfile(); parsenextc = string; parselleft = parsenleft = strlen(string); plinno = line1; INTON; CTRACE(DBG_INPUT, ("setinputstring(\"%.20s%s\" (%d), %spush, @ %d)\n", string, (parsenleft > 20 ? "..." : ""), parsenleft, push?"":"no", line1)); } /* * To handle the "." command, a stack of input files is used. Pushfile * adds a new entry to the stack and popfile restores the previous level. */ STATIC void pushfile(void) { struct parsefile *pf; VTRACE(DBG_INPUT, ("pushfile(): fd=%d buf=%p nl=%d ll=%d \"%.*s\" plinno=%d\n", parsefile->fd, parsefile->buf, parsenleft, parselleft, parsenleft, parsenextc, plinno)); parsefile->nleft = parsenleft; parsefile->lleft = parselleft; parsefile->nextc = parsenextc; parsefile->linno = plinno; pf = (struct parsefile *)ckmalloc(sizeof (struct parsefile)); pf->prev = parsefile; pf->fd = -1; pf->strpush = NULL; pf->basestrpush.prev = NULL; pf->buf = NULL; parsefile = pf; } void popfile(void) { struct parsefile *pf = parsefile; INTOFF; if (pf->fd >= 0) sh_close(pf->fd); if (pf->buf) ckfree(pf->buf); while (pf->strpush) popstring(); parsefile = pf->prev; ckfree(pf); parsenleft = parsefile->nleft; parselleft = parsefile->lleft; parsenextc = parsefile->nextc; VTRACE(DBG_INPUT, ("popfile(): fd=%d buf=%p nl=%d ll=%d \"%.*s\" plinno:%d->%d\n", parsefile->fd, parsefile->buf, parsenleft, parselleft, parsenleft, parsenextc, plinno, parsefile->linno)); plinno = parsefile->linno; INTON; } /* * Return current file (to go back to it later using popfilesupto()). */ struct parsefile * getcurrentfile(void) { return parsefile; } /* * Pop files until the given file is on top again. Useful for regular * builtins that read shell commands from files or strings. * If the given file is not an active file, an error is raised. */ void popfilesupto(struct parsefile *file) { while (parsefile != file && parsefile != &basepf) popfile(); if (parsefile != file) error("popfilesupto() misused"); } /* * Return to top level. */ void popallfiles(void) { while (parsefile != &basepf) popfile(); } /* * Close the file(s) that the shell is reading commands from. Called * after a fork is done. * * Takes one arg, vfork, which tells it to not modify its global vars * as it is still running in the parent. * * This code is (probably) unnecessary as the 'close on exec' flag is * set and should be enough. In the vfork case it is definitely wrong * to close the fds as another fork() may be done later to feed data * from a 'here' document into a pipe and we don't want to close the * pipe! */ void closescript(int vforked) { if (vforked) return; popallfiles(); if (parsefile->fd > 0) { sh_close(parsefile->fd); parsefile->fd = 0; } }