X-Git-Url: https://git.distorted.org.uk/~mdw/fwd/blobdiff_plain/e82f7154f65062d9ac8b9677862774498b331058..096c89c34505cadba1fc6e7a5367273d5c5bea47:/conf.c diff --git a/conf.c b/conf.c index 049af46..70b6506 100644 --- a/conf.c +++ b/conf.c @@ -1,69 +1,50 @@ /* -*-c-*- * - * $Id: conf.c,v 1.1 1999/07/01 08:56:23 mdw Exp $ - * * Configuration parsing * - * (c) 1999 Mark Wooding + * (c) 1999 Straylight/Edgeware */ -/*----- Licensing notice --------------------------------------------------* +/*----- Licensing notice --------------------------------------------------* * - * This file is part of the `fw' port forwarder. + * This file is part of the `fwd' port forwarder. * - * `fw' is free software; you can redistribute it and/or modify + * `fwd' is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. - * - * `fw' is distributed in the hope that it will be useful, + * + * `fwd' is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. - * + * * You should have received a copy of the GNU General Public License - * along with `fw'; if not, write to the Free Software Foundation, + * along with `fwd'; if not, write to the Free Software Foundation, * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ -/*----- Revision history --------------------------------------------------* +#include "fwd.h" + +/*----- Main code ---------------------------------------------------------*/ + +/* --- @conf_undelim@ --- * * - * $Log: conf.c,v $ - * Revision 1.1 1999/07/01 08:56:23 mdw - * Initial revision + * Arguments: @scanner *sc@ = pointer to scanner definition + * @const char *d, *dd@ = pointer to characters to escape * + * Returns: --- + * + * Use: Modifies the tokenizer. Characters in the first list will + * always be considered to begin a word. Characters in the + * second list will always be allowed to continue a word. */ -/*----- Header files ------------------------------------------------------*/ - -#include "config.h" - -#include -#include -#include -#include -#include -#include - -#include -#include -#include -#include - -#include -#include -#include - -#include "acl.h" -#include "listener.h" -#include "scan.h" - -/*----- Magic numbers -----------------------------------------------------*/ - -#define CTOK_EOF (-1) -#define CTOK_WORD 256 - -/*----- Main code ---------------------------------------------------------*/ +void conf_undelim(scanner *sc, const char *d, const char *dd) +{ + sc->wbegin = d; + sc->wcont = dd; +} /* --- @token@ --- * * @@ -74,49 +55,120 @@ * Use: Reads the next token from the character scanner. */ -static int token(scanner *sc) +int token(scanner *sc) { -#define SCAN(sc) (sc)->ops->scan((sc)) -#define UNSCAN(sc, x) (sc)->ops->unscan((x), (sc)) +#define SELFDELIM \ + '{': case '}': case '/': case ',': \ + case '=': case ':': case ';': \ + case '.': case '[': case ']' int ch; + DRESET(&sc->d); + + /* --- Main tokenization --- */ + for (;;) { - ch = SCAN(sc); - if (ch == '\n') - sc->line++; - else if (isspace((unsigned char)ch)) + ch = scan(sc); + + /* --- Deal with pushed-back tokens --- */ + + if (sc->head->tok) { + dstr_puts(&sc->d, sc->head->tok); + xfree(sc->head->tok); + sc->head->tok = 0; + sc->t = sc->head->t; + goto done; + } + + else if (isspace(ch)) ; else switch (ch) { + + /* --- End of file --- */ + case EOF: - return (sc->t = CTOK_EOF); + sc->t = CTOK_EOF; + goto done; + + /* --- Comment character --- */ + case '#': - do ch = SCAN(sc); while (ch != EOF && ch != '\n'); - if (ch == '\n') - sc->line++; + do ch = scan(sc); while (ch != EOF && ch != '\n'); break; - case '{': - case '}': - case ':': - case '/': - case ';': - return (sc->t = ch); - default: - DRESET(&sc->d); - do { - DPUTC(&sc->d, ch); - ch = SCAN(sc); - } while (ch != EOF && ch != '{' && ch != ';' && - ch != '}' && ch != ':' && ch != '/' && - !isspace((unsigned char)(ch))); - UNSCAN(sc, ch); + + /* --- Various self-delimiting characters --- */ + + case SELFDELIM: + if (!sc->wbegin || strchr(sc->wbegin, ch) == 0) { + dstr_putc(&sc->d, ch); + dstr_putz(&sc->d); + sc->t = ch; + goto done; + } + + /* --- Bare words --- * + * + * These aren't as bare any more. You can now backslash-escape + * individual characters, and enclose sections in double-quotes. + */ + + default: { + int q = 0; + + for (;;) { + switch (ch) { + case EOF: + goto word; + case '\\': + ch = scan(sc); + if (ch == EOF) + goto word; + DPUTC(&sc->d, ch); + break; + case '\"': + q = !q; + break; + case SELFDELIM: + if (q || (sc->wcont && strchr(sc->wcont, ch))) + goto insert; + goto word; + default: + if (!q && isspace(ch)) + goto word; + insert: + DPUTC(&sc->d, ch); + break; + } + ch = scan(sc); + } + word: + unscan(sc, ch); DPUTZ(&sc->d); - return (sc->t = CTOK_WORD); + sc->t = CTOK_WORD; + goto done; + } } } -#undef SCAN -#undef UNSCAN +done: + return (sc->t); +} + +/* --- @pushback@ --- * + * + * Arguments: @scanner *sc@ = pointer to scanner definition + * + * Returns: --- + * + * Use: Pushes the current token back. This is normally a precursor + * to pushing a new scanner source. + */ + +void pushback(scanner *sc) +{ + sc->head->tok = xstrdup(sc->d.buf); + sc->head->t = sc->t; } /* --- @error@ --- * @@ -130,222 +182,209 @@ static int token(scanner *sc) * Use: Reports an error at the current scanner location. */ -static void error(scanner *sc, const char *msg, ...) +void error(scanner *sc, const char *msg, ...) { va_list ap; va_start(ap, msg); - fprintf(stderr, "%s: %s:%i: ", QUIS, sc->src, sc->line); + fprintf(stderr, "%s: %s:%i: ", QUIS, sc->head->src, sc->head->line); vfprintf(stderr, msg, ap); fputc('\n', stderr); exit(1); } -/* --- @portnum@ --- * +/* --- @conf_enum@ --- * + * + * Arguments: @scanner *sc@ = pointer to a scanner object + * @const char *list@ = comma-separated things to allow + * @unsigned f@ = flags for the search + * @const char *err@ = error message if not found * - * Arguments: @scanner *sc@ = pointer to scanner (for error reporting) - * @const char *p@ = pointer to port name + * Returns: Index into list, zero-based, or @-1@. * - * Returns: Port number (network byte order) + * Use: Checks whether the current token is a string which matches + * one of the comma-separated items given. The return value is + * the index (zero-based) of the matched string in the list. * - * Use: Converts a textual port name or number into a usable thing. + * The flags control the behaviour if no exact match is found. + * If @ENUM_ABBREV@ is set, and the current token is a left + * substring of exactly one of the possibilities, then that one + * is chosen. If @ENUM_NONE@ is set, the value @-1@ is + * returned; otherwise an error is reported and the program is + * terminated. */ -static unsigned short portnum(scanner *sc, const char *p) +int conf_enum(scanner *sc, const char *list, unsigned f, const char *err) { - struct servent *s; - if (isdigit((unsigned char)*p)) - return (htons(atoi(p))); - if ((s = getservbyname(p, "tcp")) == 0) - error(sc, "unknown tcp service `%s'", p); - return (s->s_port); + const char *p, *q; + int chosen = -1; + int ok; + int index; + + /* --- Make sure it's a string --- */ + + if (sc->t != CTOK_WORD) + error(sc, "parse error, expected %s", err); + + /* --- Grind through the list --- */ + + q = sc->d.buf; + ok = 1; + index = 0; + p = list; + for (;;) { + switch (*p) { + case 0: + if (ok && !*q) { + token(sc); + return (index); + } else if (chosen != -1) { + token(sc); + return (chosen); + } + else if (f & ENUM_NONE) + return (-1); + else + error(sc, "unknown %s `%s'", err, sc->d.buf); + break; + case ',': + if (ok && !*q) { + token(sc); + return (index); + } + ok = 1; + q = sc->d.buf; + index++; + break; + default: + if (!ok) + break; + if ((f & ENUM_ABBREV) && !*q) { + if (chosen != -1) + error(sc, "ambiguous %s `%s'", err, sc->d.buf); + chosen = index; + ok = 0; + } + if (*p == *q) + q++; + else + ok = 0; + break; + } + p++; + } } -/* --- @getconf@ --- * +/* --- @conf_prefix@ --- * * - * Arguments: @scanner *sc@ = pointer to scanner to read from - * @listener *l@ = listener to configure (or zero) - * @acl_entry ***a@ = pointer to tail of ACL (or zero) + * Arguments: @scanner *sc@ = pointer to a scanner object + * @const char *p@ = pointer to prefix string to check * - * Returns: --- + * Returns: Nonzero if the prefix matches. + * + * Use: If the current token is a word matching the given prefix + * string, then it and an optional `.' character are removed and + * a nonzero result is returned. Otherwise the current token is + * left as it is, and zero is returned. * - * Use: Reads a local or global configuration statement. + * Typical options parsing code would remove an expected prefix, + * scan an option anyway (since qualifying prefixes are + * optional) and if a match is found, claim the option. If no + * match is found, and a prefix was stripped, then an error + * should be reported. */ -static void getconf(scanner *sc, listener *l, acl_entry ***a) +int conf_prefix(scanner *sc, const char *p) { - unsigned act; - - /* --- Access control limitations --- */ - - if ((strcmp(sc->d.buf, "allow") == 0 && (act = ACL_ALLOW, 1)) || - (strcmp(sc->d.buf, "deny") == 0 && (act = ACL_DENY, 1))) { - struct hostent *h; - struct netent *n; - struct in_addr addr, mask; - - /* --- Find the host or network address --- */ - + if (sc->t == CTOK_WORD && strcmp(p, sc->d.buf) == 0) { token(sc); - if (sc->t == CTOK_WORD && strcmp(sc->d.buf, "from") == 0) - token(sc); - if (sc->t != CTOK_WORD) - error(sc, "parse error, address expected"); - if ((n = getnetbyname(sc->d.buf)) != 0) - addr.s_addr = htonl(n->n_net); - else if ((h = gethostbyname(sc->d.buf)) == 0) - error(sc, "couldn't resolve address `%s'", sc->d.buf); - else - memcpy(&addr, h->h_addr, sizeof(struct in_addr)); - token(sc); - - /* --- Find the netmask, if any --- */ - - if (sc->t != '/') - mask.s_addr = ~0ul; - else { + if (sc->t == '.') token(sc); - if (sc->t != CTOK_WORD) - error(sc, "parse error, netmask expected"); - if (strchr(sc->d.buf, '.') == 0) - mask.s_addr = htonl((~0ul << (32 - atoi(sc->d.buf))) & 0xffffffff); - else { -#ifdef HAVE_INET_ATON - if (!inet_aton(sc->d.buf, &mask)) - error(sc, "bad netmask `%s'", sc->d.buf); -#else - mask.s_addr = inet_addr(sc->d.buf); -#endif - } - token(sc); - } - - /* --- Add the access control entry --- */ - - acl_add(a, act, addr, mask); + return (1); } - - /* --- Anything unrecognized --- */ - - else - error(sc, "parse error, unknown configuration keyword `%s'", sc->d.buf); + return (0); } -/* --- @conf_parse@ --- * +/* --- @conf_name@ --- * * - * Arguments: @void *scp@ = pointer to scanner definition + * Arguments: @scanner *sc@ = pointer to scanner + * @char delim@ = delimiter character to look for + * @dstr *d@ = pointer to dynamic string for output * * Returns: --- * - * Use: Parses a configuration file from the scanner. + * Use: Reads in a compound name consisting of words separated by + * delimiters. Leading and trailing delimiters are permitted, + * although they'll probably cause confusion if used. The name + * may be enclosed in square brackets if that helps at all. + * + * Examples of compound names are filenames (delimited by `/') + * and IP addresses (delimited by `.'). */ -void conf_parse(void *scp) +void conf_name(scanner *sc, char delim, dstr *d) { - scanner *sc = scp; - - token(sc); - - for (;;) { - if (sc->t == CTOK_EOF) - break; - if (sc->t != CTOK_WORD) - error(sc, "parse error, keyword expected"); + unsigned f = 0; - /* --- Handle a forwarding request --- */ +#define f_ok 1u +#define f_bra 2u - if (strcmp(sc->d.buf, "forward") == 0 || - strcmp(sc->d.buf, "fw") == 0) { - unsigned short sp, dp; - struct sockaddr_in sin; - struct hostent *h; - int fd; - listener *l; + /* --- Read an optional opening bracket --- */ - /* --- Read the source port --- */ - - token(sc); - if (sc->t == CTOK_WORD && strcmp(sc->d.buf, "port") == 0) - token(sc); - if (sc->t != CTOK_WORD) - error(sc, "parse error, source port expected"); - sp = portnum(sc, sc->d.buf); + if (sc->t == '[') { + token(sc); + f |= f_bra | f_ok; + } - /* --- Read the destination address --- */ + /* --- Do the main reading sequence --- */ + do { + if (sc->t == delim) { + DPUTC(d, delim); + f |= f_ok; token(sc); - if (sc->t == CTOK_WORD && strcmp(sc->d.buf, "to") == 0) - token(sc); - if (sc->t != CTOK_WORD) - error(sc, "parse error, destination address expected"); - if ((h = gethostbyname(sc->d.buf)) == 0) - error(sc, "couldn't resolve address `%s'", sc->d.buf); - + } + if (sc->t == CTOK_WORD) { + DPUTD(d, &sc->d); + f |= f_ok; token(sc); - if (sc->t == ':') - token(sc); - if (sc->t != CTOK_WORD) - error(sc, "parse error, destination port expected"); - dp = portnum(sc, sc->d.buf); - - /* --- Make the socket --- */ - - if ((fd = socket(PF_INET, SOCK_STREAM, 0)) < 0) - error(sc, "couldn't create socket: %s", strerror(errno)); - - /* --- Set it to allow address reuse --- */ - - { - int opt = 1; - setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt)); - } - - /* --- Bind it to the right port --- */ - - sin.sin_family = AF_INET; - sin.sin_addr.s_addr = htonl(INADDR_ANY); - sin.sin_port = sp; - if (bind(fd, (struct sockaddr *)&sin, sizeof(sin))) { - error(sc, "couldn't bind to port %i: %s", - ntohs(sp), strerror(errno)); - } - - /* --- Set it to listen for connections --- */ - - if (listen(fd, 5)) - error(sc, "couldn't listen on socket: %s", strerror(errno)); + } + } while (sc->t == delim); - /* --- Fill in a new listener --- */ + /* --- Check that the string was OK --- */ - memcpy(&sin.sin_addr, h->h_addr, sizeof(struct in_addr)); - sin.sin_port = dp; - l = listener_add(fd, sp, &sin); + if (!(f & f_ok)) + error(sc, "parse error, name expected"); - /* --- Snarf access controls and other attributes --- */ + /* --- Read a closing bracket --- */ + if (f & f_bra) { + if (sc->t == ']') token(sc); - if (sc->t == '{') { - acl_entry **a = &l->acl; - token(sc); - while (sc->t != '}') { - if (sc->t != CTOK_WORD) - error(sc, "parse error, keyword or `}' expected"); - getconf(sc, l, &a); - if (sc->t == ';') - token(sc); - } - *a = 0; - token(sc); - } - } + else + error(sc, "parse error, missing `]'"); + } + DPUTZ(d); - /* --- Other configuration is handled elsewhere --- */ +#undef f_ok +#undef f_bra +} - else - getconf(sc, 0, 0); +/* --- @conf_fname@ --- * + * + * Arguments: @scanner *sc@ = pointer to scanner + * @dstr *d@ = pointer to dynamic string for output + * + * Returns: --- + * + * Use: Reads a file name from the input and stores it in @d@. + */ - if (sc->t == ';') - token(sc); - } +void conf_fname(scanner *sc, dstr *d) +{ + const char fnchars[] = ".-+"; + conf_undelim(sc, fnchars, fnchars); + conf_name(sc, '/', d); + conf_undelim(sc, 0, 0); } /*----- That's all, folks -------------------------------------------------*/