/* $NetBSD: unifdef.c,v 1.17 2010/01/20 19:02:42 ginsbach Exp $ */ /* * Copyright (c) 1985, 1993 * The Regents of the University of California. All rights reserved. * * This code is derived from software contributed to Berkeley by * Dave Yost. It was rewritten to support ANSI C by Tony Finch. * * 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. */ /* * Copyright (c) 2002, 2003 Tony Finch * * This code is derived from software contributed to Berkeley by * Dave Yost. It was rewritten to support ANSI C by Tony Finch. * * 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. */ #include #ifndef lint #if 0 static const char copyright[] = "@(#) Copyright (c) 1985, 1993\n\ The Regents of the University of California. All rights reserved.\n"; #endif #ifdef __IDSTRING __IDSTRING(Berkeley, "@(#)unifdef.c 8.1 (Berkeley) 6/6/93"); __IDSTRING(NetBSD, "$NetBSD: unifdef.c,v 1.17 2010/01/20 19:02:42 ginsbach Exp $"); __IDSTRING(dotat, "$dotat: things/unifdef.c,v 1.161 2003/07/01 15:32:48 fanf2 Exp $"); #endif #endif /* not lint */ #ifdef __FBSDID __FBSDID("$FreeBSD: src/usr.bin/unifdef/unifdef.c,v 1.18 2003/07/01 15:30:43 fanf Exp $"); #endif /* * unifdef - remove ifdef'ed lines * * Wishlist: * provide an option which will append the name of the * appropriate symbol after #else's and #endif's * provide an option which will check symbols after * #else's and #endif's to see that they match their * corresponding #ifdef or #ifndef * generate #line directives in place of deleted code * * The first two items above require better buffer handling, which would * also make it possible to handle all "dodgy" directives correctly. */ #include #include #include #include #include #include #include #include #include #include #include "stdbool.h" /* types of input lines: */ typedef enum { LT_TRUEI, /* a true #if with ignore flag */ LT_FALSEI, /* a false #if with ignore flag */ LT_IF, /* an unknown #if */ LT_TRUE, /* a true #if */ LT_FALSE, /* a false #if */ LT_ELIF, /* an unknown #elif */ LT_ELTRUE, /* a true #elif */ LT_ELFALSE, /* a false #elif */ LT_ELSE, /* #else */ LT_ENDIF, /* #endif */ LT_DODGY, /* flag: directive is not on one line */ LT_DODGY_LAST = LT_DODGY + LT_ENDIF, LT_PLAIN, /* ordinary line */ LT_EOF, /* end of file */ LT_COUNT } Linetype; static char const * const linetype_name[] = { "TRUEI", "FALSEI", "IF", "TRUE", "FALSE", "ELIF", "ELTRUE", "ELFALSE", "ELSE", "ENDIF", "DODGY TRUEI", "DODGY FALSEI", "DODGY IF", "DODGY TRUE", "DODGY FALSE", "DODGY ELIF", "DODGY ELTRUE", "DODGY ELFALSE", "DODGY ELSE", "DODGY ENDIF", "PLAIN", "EOF" }; /* state of #if processing */ typedef enum { IS_OUTSIDE, IS_FALSE_PREFIX, /* false #if followed by false #elifs */ IS_TRUE_PREFIX, /* first non-false #(el)if is true */ IS_PASS_MIDDLE, /* first non-false #(el)if is unknown */ IS_FALSE_MIDDLE, /* a false #elif after a pass state */ IS_TRUE_MIDDLE, /* a true #elif after a pass state */ IS_PASS_ELSE, /* an else after a pass state */ IS_FALSE_ELSE, /* an else after a true state */ IS_TRUE_ELSE, /* an else after only false states */ IS_FALSE_TRAILER, /* #elifs after a true are false */ IS_COUNT } Ifstate; static char const * const ifstate_name[] = { "OUTSIDE", "FALSE_PREFIX", "TRUE_PREFIX", "PASS_MIDDLE", "FALSE_MIDDLE", "TRUE_MIDDLE", "PASS_ELSE", "FALSE_ELSE", "TRUE_ELSE", "FALSE_TRAILER" }; /* state of comment parser */ typedef enum { NO_COMMENT = false, /* outside a comment */ C_COMMENT, /* in a comment like this one */ CXX_COMMENT, /* between // and end of line */ STARTING_COMMENT, /* just after slash-backslash-newline */ FINISHING_COMMENT /* star-backslash-newline in a C comment */ } Comment_state; static char const * const comment_name[] = { "NO", "C", "CXX", "STARTING", "FINISHING" }; /* state of preprocessor line parser */ typedef enum { LS_START, /* only space and comments on this line */ LS_HASH, /* only space, comments, and a hash */ LS_DIRTY /* this line can't be a preprocessor line */ } Line_state; static char const * const linestate_name[] = { "START", "HASH", "DIRTY" }; /* * Minimum translation limits from ISO/IEC 9899:1999 5.2.4.1 */ #define MAXDEPTH 64 /* maximum #if nesting */ #define MAXLINE 4096 /* maximum length of line */ #define MAXSYMS 4096 /* maximum number of symbols */ /* * Sometimes when editing a keyword the replacement text is longer, so * we leave some space at the end of the tline buffer to accommodate this. */ #define EDITSLOP 10 /* * Globals. */ static bool complement; /* -c: do the complement */ static bool debugging; /* -d: debugging reports */ static bool iocccok; /* -e: fewer IOCCC errors */ static bool killconsts; /* -k: eval constant #ifs */ static bool lnblank; /* -l: blank deleted lines */ static bool symlist; /* -s: output symbol list */ static bool text; /* -t: this is a text file */ static const char *symname[MAXSYMS]; /* symbol name */ static const char *value[MAXSYMS]; /* -Dsym=value */ static bool ignore[MAXSYMS]; /* -iDsym or -iUsym */ static int nsyms; /* number of symbols */ static FILE *input; /* input file pointer */ static FILE *output; /* output file pointer */ static const char *filename; /* input file name */ static char *ofilename; /* output file name */ static char tmpname[MAXPATHLEN]; /* used when overwriting */ static int linenum; /* current line number */ static int overwriting; /* output overwrites input */ static char tline[MAXLINE+EDITSLOP];/* input buffer plus space */ static char *keyword; /* used for editing #elif's */ static Comment_state incomment; /* comment parser state */ static Line_state linestate; /* #if line parser state */ static Ifstate ifstate[MAXDEPTH]; /* #if processor state */ static bool ignoring[MAXDEPTH]; /* ignore comments state */ static int stifline[MAXDEPTH]; /* start of current #if */ static int depth; /* current #if nesting */ static bool keepthis; /* don't delete constant #if */ static int exitstat; /* program exit status */ static void addsym(bool, bool, char *); static void debug(const char *, ...); static void done(void); static void error(const char *); static int findsym(const char *); static void flushline(bool); static Linetype get_line(void); static Linetype ifeval(const char **); static void ignoreoff(void); static void ignoreon(void); static void keywordedit(const char *); static void nest(void); static void process(void); static const char *skipcomment(const char *); static const char *skipsym(const char *); static void state(Ifstate); static int strlcmp(const char *, const char *, size_t); static void usage(void); #define endsym(c) (!isalpha((unsigned char)c) && !isdigit((unsigned char)c) && c != '_') /* * The main program. */ int main(int argc, char *argv[]) { int opt; struct stat isb, osb; while ((opt = getopt(argc, argv, "i:D:U:I:o:cdeklst")) != -1) switch (opt) { case 'i': /* treat stuff controlled by these symbols as text */ /* * For strict backwards-compatibility the U or D * should be immediately after the -i but it doesn't * matter much if we relax that requirement. */ opt = *optarg++; if (opt == 'D') addsym(true, true, optarg); else if (opt == 'U') addsym(true, false, optarg); else usage(); break; case 'D': /* define a symbol */ addsym(false, true, optarg); break; case 'U': /* undef a symbol */ addsym(false, false, optarg); break; case 'I': /* no-op for compatibility with cpp */ break; case 'c': /* treat -D as -U and vice versa */ complement = true; break; case 'd': debugging = true; break; case 'e': /* fewer errors from dodgy lines */ iocccok = true; break; case 'k': /* process constant #ifs */ killconsts = true; break; case 'l': /* blank deleted lines instead of omitting them */ lnblank = true; break; case 'o': /* output to a file */ ofilename = optarg; break; case 's': /* only output list of symbols that control #ifs */ symlist = true; break; case 't': /* don't parse C comments */ text = true; break; default: usage(); } argc -= optind; argv += optind; if (nsyms == 0 && !symlist) { warnx("must -D or -U at least one symbol"); usage(); } if (argc > 1) { errx(2, "can only do one file"); } else if (argc == 1 && strcmp(*argv, "-") != 0) { filename = *argv; input = fopen(filename, "r"); if (input == NULL) err(2, "can't open %s", filename); } else { filename = "[stdin]"; input = stdin; } if (ofilename == NULL) { output = stdout; } else { if (stat(ofilename, &osb) == 0) { if (fstat(fileno(input), &isb) != 0) err(2, "can't fstat %s", filename); overwriting = (osb.st_dev == isb.st_dev && osb.st_ino == osb.st_ino); } if (overwriting) { int ofd; snprintf(tmpname, sizeof(tmpname), "%s/unifdef.XXXXXX", dirname(ofilename)); if ((ofd = mkstemp(tmpname)) != -1) output = fdopen(ofd, "w+"); if (output == NULL) err(2, "can't create temporary file"); fchmod(ofd, isb.st_mode & ACCESSPERMS); } else { output = fopen(ofilename, "w"); if (output == NULL) err(2, "can't open %s", ofilename); } } process(); abort(); /* bug */ } static void usage(void) { fprintf(stderr, "usage: unifdef [-cdeklst] [-o output]" " [-Dsym[=val]] [-Usym] [-iDsym[=val]] [-iUsym] ... [file]\n"); exit(2); } /* * A state transition function alters the global #if processing state * in a particular way. The table below is indexed by the current * processing state and the type of the current line. * * Nesting is handled by keeping a stack of states; some transition * functions increase or decrease the depth. They also maintain the * ignore state on a stack. In some complicated cases they have to * alter the preprocessor directive, as follows. * * When we have processed a group that starts off with a known-false * #if/#elif sequence (which has therefore been deleted) followed by a * #elif that we don't understand and therefore must keep, we edit the * latter into a #if to keep the nesting correct. * * When we find a true #elif in a group, the following block will * always be kept and the rest of the sequence after the next #elif or * #else will be discarded. We edit the #elif into a #else and the * following directive to #endif since this has the desired behaviour. * * "Dodgy" directives are split across multiple lines, the most common * example being a multi-line comment hanging off the right of the * directive. We can handle them correctly only if there is no change * from printing to dropping (or vice versa) caused by that directive. * If the directive is the first of a group we have a choice between * failing with an error, or passing it through unchanged instead of * evaluating it. The latter is not the default to avoid questions from * users about unifdef unexpectedly leaving behind preprocessor directives. */ typedef void state_fn(void); /* report an error */ static void Eelif (void) { error("Inappropriate #elif"); } static void Eelse (void) { error("Inappropriate #else"); } static void Eendif(void) { error("Inappropriate #endif"); } static void Eeof (void) { error("Premature EOF"); } static void Eioccc(void) { error("Obfuscated preprocessor control line"); } /* plain line handling */ static void print (void) { flushline(true); } static void drop (void) { flushline(false); } /* output lacks group's start line */ static void Strue (void) { drop(); ignoreoff(); state(IS_TRUE_PREFIX); } static void Sfalse(void) { drop(); ignoreoff(); state(IS_FALSE_PREFIX); } static void Selse (void) { drop(); state(IS_TRUE_ELSE); } /* print/pass this block */ static void Pelif (void) { print(); ignoreoff(); state(IS_PASS_MIDDLE); } static void Pelse (void) { print(); state(IS_PASS_ELSE); } static void Pendif(void) { print(); --depth; } /* discard this block */ static void Dfalse(void) { drop(); ignoreoff(); state(IS_FALSE_TRAILER); } static void Delif (void) { drop(); ignoreoff(); state(IS_FALSE_MIDDLE); } static void Delse (void) { drop(); state(IS_FALSE_ELSE); } static void Dendif(void) { drop(); --depth; } /* first line of group */ static void Fdrop (void) { nest(); Dfalse(); } static void Fpass (void) { nest(); Pelif(); } static void Ftrue (void) { nest(); Strue(); } static void Ffalse(void) { nest(); Sfalse(); } /* variable pedantry for obfuscated lines */ static void Oiffy (void) { if (iocccok) Fpass(); else Eioccc(); ignoreon(); } static void Oif (void) { if (iocccok) Fpass(); else Eioccc(); } static void Oelif (void) { if (iocccok) Pelif(); else Eioccc(); } /* ignore comments in this block */ static void Idrop (void) { Fdrop(); ignoreon(); } static void Itrue (void) { Ftrue(); ignoreon(); } static void Ifalse(void) { Ffalse(); ignoreon(); } /* edit this line */ static void Mpass (void) { strncpy(keyword, "if ", 4); Pelif(); } static void Mtrue (void) { keywordedit("else\n"); state(IS_TRUE_MIDDLE); } static void Melif (void) { keywordedit("endif\n"); state(IS_FALSE_TRAILER); } static void Melse (void) { keywordedit("endif\n"); state(IS_FALSE_ELSE); } static state_fn * const trans_table[IS_COUNT][LT_COUNT] = { /* IS_OUTSIDE */ { Itrue, Ifalse,Fpass, Ftrue, Ffalse,Eelif, Eelif, Eelif, Eelse, Eendif, Oiffy, Oiffy, Fpass, Oif, Oif, Eelif, Eelif, Eelif, Eelse, Eendif, print, done }, /* IS_FALSE_PREFIX */ { Idrop, Idrop, Fdrop, Fdrop, Fdrop, Mpass, Strue, Sfalse,Selse, Dendif, Idrop, Idrop, Fdrop, Fdrop, Fdrop, Mpass, Eioccc,Eioccc,Eioccc,Eioccc, drop, Eeof }, /* IS_TRUE_PREFIX */ { Itrue, Ifalse,Fpass, Ftrue, Ffalse,Dfalse,Dfalse,Dfalse,Delse, Dendif, Oiffy, Oiffy, Fpass, Oif, Oif, Eioccc,Eioccc,Eioccc,Eioccc,Eioccc, print, Eeof }, /* IS_PASS_MIDDLE */ { Itrue, Ifalse,Fpass, Ftrue, Ffalse,Pelif, Mtrue, Delif, Pelse, Pendif, Oiffy, Oiffy, Fpass, Oif, Oif, Pelif, Oelif, Oelif, Pelse, Pendif, print, Eeof }, /* IS_FALSE_MIDDLE */ { Idrop, Idrop, Fdrop, Fdrop, Fdrop, Pelif, Mtrue, Delif, Pelse, Pendif, Idrop, Idrop, Fdrop, Fdrop, Fdrop, Eioccc,Eioccc,Eioccc,Eioccc,Eioccc, drop, Eeof }, /* IS_TRUE_MIDDLE */ { Itrue, Ifalse,Fpass, Ftrue, Ffalse,Melif, Melif, Melif, Melse, Pendif, Oiffy, Oiffy, Fpass, Oif, Oif, Eioccc,Eioccc,Eioccc,Eioccc,Pendif, print, Eeof }, /* IS_PASS_ELSE */ { Itrue, Ifalse,Fpass, Ftrue, Ffalse,Eelif, Eelif, Eelif, Eelse, Pendif, Oiffy, Oiffy, Fpass, Oif, Oif, Eelif, Eelif, Eelif, Eelse, Pendif, print, Eeof }, /* IS_FALSE_ELSE */ { Idrop, Idrop, Fdrop, Fdrop, Fdrop, Eelif, Eelif, Eelif, Eelse, Dendif, Idrop, Idrop, Fdrop, Fdrop, Fdrop, Eelif, Eelif, Eelif, Eelse, Eioccc, drop, Eeof }, /* IS_TRUE_ELSE */ { Itrue, Ifalse,Fpass, Ftrue, Ffalse,Eelif, Eelif, Eelif, Eelse, Dendif, Oiffy, Oiffy, Fpass, Oif, Oif, Eelif, Eelif, Eelif, Eelse, Eioccc, print, Eeof }, /* IS_FALSE_TRAILER */ { Idrop, Idrop, Fdrop, Fdrop, Fdrop, Dfalse,Dfalse,Dfalse,Delse, Dendif, Idrop, Idrop, Fdrop, Fdrop, Fdrop, Dfalse,Dfalse,Dfalse,Delse, Eioccc, drop, Eeof } /*TRUEI FALSEI IF TRUE FALSE ELIF ELTRUE ELFALSE ELSE ENDIF TRUEI FALSEI IF TRUE FALSE ELIF ELTRUE ELFALSE ELSE ENDIF (DODGY) PLAIN EOF */ }; /* * State machine utility functions */ static void done(void) { if (incomment) error("EOF in comment"); if (fclose(output)) { if (overwriting) { unlink(tmpname); errx(2, "%s unchanged", filename); } } if (overwriting && rename(tmpname, filename)) { unlink(tmpname); errx(2, "%s unchanged", filename); } exit(exitstat); } static void ignoreoff(void) { ignoring[depth] = ignoring[depth-1]; } static void ignoreon(void) { ignoring[depth] = true; } static void keywordedit(const char *replacement) { strlcpy(keyword, replacement, tline + sizeof(tline) - keyword); print(); } static void nest(void) { depth += 1; if (depth >= MAXDEPTH) error("Too many levels of nesting"); stifline[depth] = linenum; } static void state(Ifstate is) { ifstate[depth] = is; } /* * Write a line to the output or not, according to command line options. */ static void flushline(bool keep) { if (symlist) return; if (keep ^ complement) fputs(tline, output); else { if (lnblank) putc('\n', output); exitstat = 1; } } /* * The driver for the state machine. */ static void process(void) { Linetype lineval; for (;;) { linenum++; lineval = get_line(); trans_table[ifstate[depth]][lineval](); debug("process %s -> %s depth %d", linetype_name[lineval], ifstate_name[ifstate[depth]], depth); } } /* * Parse a line and determine its type. We keep the preprocessor line * parser state between calls in the global variable linestate, with * help from skipcomment(). */ static Linetype get_line(void) { const char *cp; int cursym; int kwlen; Linetype retval; Comment_state wascomment; if (fgets(tline, MAXLINE, input) == NULL) return (LT_EOF); retval = LT_PLAIN; wascomment = incomment; cp = skipcomment(tline); if (linestate == LS_START) { if (*cp == '#') { linestate = LS_HASH; cp = skipcomment(cp + 1); } else if (*cp != '\0') linestate = LS_DIRTY; } if (!incomment && linestate == LS_HASH) { keyword = tline + (cp - tline); cp = skipsym(cp); kwlen = cp - keyword; /* no way can we deal with a continuation inside a keyword */ if (strncmp(cp, "\\\n", 2) == 0) Eioccc(); if (strlcmp("ifdef", keyword, kwlen) == 0 || strlcmp("ifndef", keyword, kwlen) == 0) { cp = skipcomment(cp); if ((cursym = findsym(cp)) < 0) retval = LT_IF; else { retval = (keyword[2] == 'n') ? LT_FALSE : LT_TRUE; if (value[cursym] == NULL) retval = (retval == LT_TRUE) ? LT_FALSE : LT_TRUE; if (ignore[cursym]) retval = (retval == LT_TRUE) ? LT_TRUEI : LT_FALSEI; } cp = skipsym(cp); } else if (strlcmp("if", keyword, kwlen) == 0) retval = ifeval(&cp); else if (strlcmp("elif", keyword, kwlen) == 0) retval = ifeval(&cp) - LT_IF + LT_ELIF; else if (strlcmp("else", keyword, kwlen) == 0) retval = LT_ELSE; else if (strlcmp("endif", keyword, kwlen) == 0) retval = LT_ENDIF; else { linestate = LS_DIRTY; retval = LT_PLAIN; } cp = skipcomment(cp); if (*cp != '\0') { linestate = LS_DIRTY; if (retval == LT_TRUE || retval == LT_FALSE || retval == LT_TRUEI || retval == LT_FALSEI) retval = LT_IF; if (retval == LT_ELTRUE || retval == LT_ELFALSE) retval = LT_ELIF; } if (retval != LT_PLAIN && (wascomment || incomment)) { retval += LT_DODGY; if (incomment) linestate = LS_DIRTY; } /* skipcomment should have changed the state */ if (linestate == LS_HASH) abort(); /* bug */ } if (linestate == LS_DIRTY) { while (*cp != '\0') cp = skipcomment(cp + 1); } debug("parser %s comment %s line", comment_name[incomment], linestate_name[linestate]); return (retval); } /* * These are the binary operators that are supported by the expression * evaluator. Note that if support for division is added then we also * need short-circuiting booleans because of divide-by-zero. */ static int op_lt(int a, int b) { return (a < b); } static int op_gt(int a, int b) { return (a > b); } static int op_le(int a, int b) { return (a <= b); } static int op_ge(int a, int b) { return (a >= b); } static int op_eq(int a, int b) { return (a == b); } static int op_ne(int a, int b) { return (a != b); } static int op_or(int a, int b) { return (a || b); } static int op_and(int a, int b) { return (a && b); } /* * An evaluation function takes three arguments, as follows: (1) a pointer to * an element of the precedence table which lists the operators at the current * level of precedence; (2) a pointer to an integer which will receive the * value of the expression; and (3) a pointer to a char* that points to the * expression to be evaluated and that is updated to the end of the expression * when evaluation is complete. The function returns LT_FALSE if the value of * the expression is zero, LT_TRUE if it is non-zero, or LT_IF if the * expression could not be evaluated. */ struct ops; typedef Linetype eval_fn(const struct ops *, int *, const char **); static eval_fn eval_table, eval_unary; /* * The precedence table. Expressions involving binary operators are evaluated * in a table-driven way by eval_table. When it evaluates a subexpression it * calls the inner function with its first argument pointing to the next * element of the table. Innermost expressions have special non-table-driven * handling. */ static const struct ops { eval_fn *inner; struct op { const char *str; int (*fn)(int, int); } op[5]; } eval_ops[] = { { eval_table, { { "||", op_or } } }, { eval_table, { { "&&", op_and } } }, { eval_table, { { "==", op_eq }, { "!=", op_ne } } }, { eval_unary, { { "<=", op_le }, { ">=", op_ge }, { "<", op_lt }, { ">", op_gt } } } }; /* * Function for evaluating the innermost parts of expressions, * viz. !expr (expr) defined(symbol) symbol number * We reset the keepthis flag when we find a non-constant subexpression. */ static Linetype eval_unary(const struct ops *ops, int *valp, const char **cpp) { const char *cp; char *ep; int sym; cp = skipcomment(*cpp); if (*cp == '!') { debug("eval%d !", ops - eval_ops); cp++; if (eval_unary(ops, valp, &cp) == LT_IF) return (LT_IF); *valp = !*valp; } else if (*cp == '(') { cp++; debug("eval%d (", ops - eval_ops); if (eval_table(eval_ops, valp, &cp) == LT_IF) return (LT_IF); cp = skipcomment(cp); if (*cp++ != ')') return (LT_IF); } else if (isdigit((unsigned char)*cp)) { debug("eval%d number", ops - eval_ops); *valp = strtol(cp, &ep, 0); cp = skipsym(cp); } else if (strncmp(cp, "defined", 7) == 0 && endsym(cp[7])) { cp = skipcomment(cp+7); debug("eval%d defined", ops - eval_ops); if (*cp++ != '(') return (LT_IF); cp = skipcomment(cp); sym = findsym(cp); if (sym < 0 || symlist) return (LT_IF); *valp = (value[sym] != NULL); cp = skipsym(cp); cp = skipcomment(cp); if (*cp++ != ')') return (LT_IF); keepthis = false; } else if (!endsym(*cp)) { debug("eval%d symbol", ops - eval_ops); sym = findsym(cp); if (sym < 0 || symlist) return (LT_IF); if (value[sym] == NULL) *valp = 0; else { *valp = strtol(value[sym], &ep, 0); if (*ep != '\0' || ep == value[sym]) return (LT_IF); } cp = skipsym(cp); keepthis = false; } else { debug("eval%d bad expr", ops - eval_ops); return (LT_IF); } *cpp = cp; debug("eval%d = %d", ops - eval_ops, *valp); return (*valp ? LT_TRUE : LT_FALSE); } /* * Table-driven evaluation of binary operators. */ static Linetype eval_table(const struct ops *ops, int *valp, const char **cpp) { const struct op *op; const char *cp; int val; debug("eval%d", ops - eval_ops); cp = *cpp; if (ops->inner(ops+1, valp, &cp) == LT_IF) return (LT_IF); for (;;) { cp = skipcomment(cp); for (op = ops->op; op->str != NULL; op++) if (strncmp(cp, op->str, strlen(op->str)) == 0) break; if (op->str == NULL) break; cp += strlen(op->str); debug("eval%d %s", ops - eval_ops, op->str); if (ops->inner(ops+1, &val, &cp) == LT_IF) return (LT_IF); *valp = op->fn(*valp, val); } *cpp = cp; debug("eval%d = %d", ops - eval_ops, *valp); return (*valp ? LT_TRUE : LT_FALSE); } /* * Evaluate the expression on a #if or #elif line. If we can work out * the result we return LT_TRUE or LT_FALSE accordingly, otherwise we * return just a generic LT_IF. */ static Linetype ifeval(const char **cpp) { int ret; int val; debug("eval %s", *cpp); keepthis = killconsts ? false : true; ret = eval_table(eval_ops, &val, cpp); debug("eval = %d", val); return (keepthis ? LT_IF : ret); } /* * Skip over comments and stop at the next character position that is * not whitespace. Between calls we keep the comment state in the * global variable incomment, and we also adjust the global variable * linestate when we see a newline. * XXX: doesn't cope with the buffer splitting inside a state transition. */ static const char * skipcomment(const char *cp) { if (text || ignoring[depth]) { for (; isspace((unsigned char)*cp); cp++) if (*cp == '\n') linestate = LS_START; return (cp); } while (*cp != '\0') /* don't reset to LS_START after a line continuation */ if (strncmp(cp, "\\\n", 2) == 0) cp += 2; else switch (incomment) { case NO_COMMENT: if (strncmp(cp, "/\\\n", 3) == 0) { incomment = STARTING_COMMENT; cp += 3; } else if (strncmp(cp, "/*", 2) == 0) { incomment = C_COMMENT; cp += 2; } else if (strncmp(cp, "//", 2) == 0) { incomment = CXX_COMMENT; cp += 2; } else if (strncmp(cp, "\n", 1) == 0) { linestate = LS_START; cp += 1; } else if (strchr(" \t", *cp) != NULL) { cp += 1; } else return (cp); continue; case CXX_COMMENT: if (strncmp(cp, "\n", 1) == 0) { incomment = NO_COMMENT; linestate = LS_START; } cp += 1; continue; case C_COMMENT: if (strncmp(cp, "*\\\n", 3) == 0) { incomment = FINISHING_COMMENT; cp += 3; } else if (strncmp(cp, "*/", 2) == 0) { incomment = NO_COMMENT; cp += 2; } else cp += 1; continue; case STARTING_COMMENT: if (*cp == '*') { incomment = C_COMMENT; cp += 1; } else if (*cp == '/') { incomment = CXX_COMMENT; cp += 1; } else { incomment = NO_COMMENT; linestate = LS_DIRTY; } continue; case FINISHING_COMMENT: if (*cp == '/') { incomment = NO_COMMENT; cp += 1; } else incomment = C_COMMENT; continue; default: abort(); /* bug */ } return (cp); } /* * Skip over an identifier. */ static const char * skipsym(const char *cp) { while (!endsym(*cp)) ++cp; return (cp); } /* * Look for the symbol in the symbol table. If is is found, we return * the symbol table index, else we return -1. */ static int findsym(const char *str) { const char *cp; int symind; cp = skipsym(str); if (cp == str) return (-1); if (symlist) printf("%.*s\n", (int)(cp-str), str); for (symind = 0; symind < nsyms; ++symind) { if (strlcmp(symname[symind], str, cp-str) == 0) { debug("findsym %s %s", symname[symind], value[symind] ? value[symind] : ""); return (symind); } } return (-1); } /* * Add a symbol to the symbol table. */ static void addsym(bool ignorethis, bool definethis, char *sym) { int symind; char *val; symind = findsym(sym); if (symind < 0) { if (nsyms >= MAXSYMS) errx(2, "too many symbols"); symind = nsyms++; } symname[symind] = sym; ignore[symind] = ignorethis; val = sym + (skipsym(sym) - sym); if (definethis) { if (*val == '=') { value[symind] = val+1; *val = '\0'; } else if (*val == '\0') value[symind] = ""; else usage(); } else { if (*val != '\0') usage(); value[symind] = NULL; } } /* * Compare s with n characters of t. * The same as strncmp() except that it checks that s[n] == '\0'. */ static int strlcmp(const char *s, const char *t, size_t n) { while (n-- && *t != '\0') if (*s != *t) return ((unsigned char)*s - (unsigned char)*t); else ++s, ++t; return ((unsigned char)*s); } /* * Diagnostics. */ static void debug(const char *msg, ...) { va_list ap; if (debugging) { va_start(ap, msg); vwarnx(msg, ap); va_end(ap); } } static void error(const char *msg) { if (depth == 0) warnx("%s: %d: %s", filename, linenum, msg); else warnx("%s: %d: %s (#if line %d depth %d)", filename, linenum, msg, stifline[depth], depth); fclose(output); if (overwriting) { unlink(tmpname); errx(2, "%s unchanged", filename); } errx(2, "output may be truncated"); }