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authorIngo Schwarze <schwarze@openbsd.org>2022-05-19 15:37:47 +0000
committerIngo Schwarze <schwarze@openbsd.org>2022-05-19 15:37:47 +0000
commitd824ca436a24afd9d96f4c85ac1e813d559bc063 (patch)
tree1a84149865a4bea364b417b930e8dc47c262c168 /mandoc.c
parent357a222c192066a0a66051f7ab345481049d8907 (diff)
downloadmandoc-d824ca436a24afd9d96f4c85ac1e813d559bc063.tar.gz
Make roff_expand() parse left-to-right rather than right-to-left.
Some escape sequences have side effects on global state, implying that the order of evaluation matters. For example, this fixes the long-standing bug that "\n+x\n+x\n+x" after ".nr x 0 1" used to print "321"; now it correctly prints "123". Right-to-left parsing was convenient because it implicitly handled nested escape sequences. With correct left-to-right parsing, nesting now requires an explicit implementation, here solved as follows: 1. Handle nested expanding escape sequences iteratively. When finding one, expand it, then retry parsing the enclosing escape sequence from the beginning, which will ultimately succeed as soon as it no longer contains any nested expanding escape sequences. 2. Handle nested non-expanding escape sequences recursively. When finding one, the escape sequence parser calls itself to find the end of the inner sequence, then continues parsing the outer sequence after that point. This requires the mandoc_escape() function to operate in two different modes. The roff(7) parser uses it in a mode where it generates diagnostics and may return an expansion request instead of a parse result. All other callers, in particular the formatters, use it in a simpler mode that never generates diagnostics and always returns a definite parsing result, but that requires all expanding escape sequences to already have been expanded earlier. The bulk of the code is the same for both modes. Since this required a major rewrite of the function anyway, move it into its own new file roff_escape.c and out of the file mandoc.c, which was misnamed in the first place and lacks a clear focus. As a side benefit, this also fixes a number of assertion failures that tb@ found with afl(1), for example "\n\\\\*0", "\v\-\\*0", and "\w\-\\\\\$0*0". As another side benefit, it also resolves some code duplication between mandoc_escape() and roff_expand() and centralizes all handling of escape sequences (except for expansion) in roff_escape.c, hopefully easing maintenance and feature improvements in the future. While here, also move end-of-input handling out of the complicated function roff_expand() and into the simpler function roff_parse_comment(), making the logic easier to understand. Since this is a major reorganization of a central component of mandoc(1), stability of the program might slightly suffer for a few weeks, but i believe that's not a problem at this point of the release cycle. The new code already satisfies the regression suite, but more tweaking and regression testing to further improve the handling of various escape sequences will likely follow in the near future.
Diffstat (limited to 'mandoc.c')
-rw-r--r--mandoc.c392
1 files changed, 8 insertions, 384 deletions
diff --git a/mandoc.c b/mandoc.c
index 2abbbd56..a1ddc72b 100644
--- a/mandoc.c
+++ b/mandoc.c
@@ -1,7 +1,8 @@
/* $Id$ */
/*
- * Copyright (c) 2011-2015, 2017-2022 Ingo Schwarze <schwarze@openbsd.org>
- * Copyright (c) 2008-2011, 2014 Kristaps Dzonsons <kristaps@bsd.lv>
+ * Copyright (c) 2010, 2011, 2015, 2017, 2018, 2019, 2020, 2021
+ * Ingo Schwarze <schwarze@openbsd.org>
+ * Copyright (c) 2009, 2010 Kristaps Dzonsons <kristaps@bsd.lv>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
@@ -14,6 +15,11 @@
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ * Utility functions to handle end of sentence punctuation
+ * and dates and times, for use by mdoc(7) and man(7) parsers.
+ * Utility functions to handle fonts and numbers,
+ * for use by mandoc(1) parsers and formatters.
*/
#include "config.h"
@@ -91,388 +97,6 @@ mandoc_font(const char *cp, int sz)
}
}
-enum mandoc_esc
-mandoc_escape(const char **end, const char **start, int *sz)
-{
- const char *local_start;
- int local_sz, c, i;
- char term;
- enum mandoc_esc gly;
-
- /*
- * When the caller doesn't provide return storage,
- * use local storage.
- */
-
- if (NULL == start)
- start = &local_start;
- if (NULL == sz)
- sz = &local_sz;
-
- /*
- * Treat "\E" just like "\";
- * it only makes a difference in copy mode.
- */
-
- while (**end == 'E')
- ++*end;
-
- /*
- * Beyond the backslash, at least one input character
- * is part of the escape sequence. With one exception
- * (see below), that character won't be returned.
- */
-
- gly = ESCAPE_ERROR;
- *start = ++*end;
- *sz = 0;
- term = '\0';
-
- switch ((*start)[-1]) {
- /*
- * First the glyphs. There are several different forms of
- * these, but each eventually returns a substring of the glyph
- * name.
- */
- case '(':
- gly = ESCAPE_SPECIAL;
- *sz = 2;
- break;
- case '[':
- if (**start == ' ') {
- ++*end;
- return ESCAPE_ERROR;
- }
- gly = ESCAPE_SPECIAL;
- term = ']';
- break;
- case 'C':
- if ('\'' != **start)
- return ESCAPE_ERROR;
- *start = ++*end;
- gly = ESCAPE_SPECIAL;
- term = '\'';
- break;
-
- /*
- * Escapes taking no arguments at all.
- */
- case '!':
- case '?':
- return ESCAPE_UNSUPP;
- case '%':
- case '&':
- case ')':
- case ',':
- case '/':
- case '^':
- case 'a':
- case 'd':
- case 'r':
- case 't':
- case 'u':
- case '{':
- case '|':
- case '}':
- return ESCAPE_IGNORE;
- case 'c':
- return ESCAPE_NOSPACE;
- case 'p':
- return ESCAPE_BREAK;
-
- /*
- * The \z escape is supposed to output the following
- * character without advancing the cursor position.
- * Since we are mostly dealing with terminal mode,
- * let us just skip the next character.
- */
- case 'z':
- return ESCAPE_SKIPCHAR;
-
- /*
- * Handle all triggers matching \X(xy, \Xx, and \X[xxxx], where
- * 'X' is the trigger. These have opaque sub-strings.
- */
- case 'F':
- case 'f':
- case 'g':
- case 'k':
- case 'M':
- case 'm':
- case 'n':
- case 'O':
- case 'V':
- case 'Y':
- case '*':
- switch ((*start)[-1]) {
- case 'f':
- gly = ESCAPE_FONT;
- break;
- case '*':
- gly = ESCAPE_DEVICE;
- break;
- default:
- gly = ESCAPE_IGNORE;
- break;
- }
- switch (**start) {
- case '(':
- if ((*start)[-1] == 'O')
- gly = ESCAPE_ERROR;
- *start = ++*end;
- *sz = 2;
- break;
- case '[':
- if ((*start)[-1] == 'O')
- gly = (*start)[1] == '5' ?
- ESCAPE_UNSUPP : ESCAPE_ERROR;
- *start = ++*end;
- term = ']';
- break;
- default:
- if ((*start)[-1] == 'O') {
- switch (**start) {
- case '0':
- gly = ESCAPE_UNSUPP;
- break;
- case '1':
- case '2':
- case '3':
- case '4':
- break;
- default:
- gly = ESCAPE_ERROR;
- break;
- }
- }
- *sz = 1;
- break;
- }
- break;
-
- /*
- * These escapes are of the form \X'Y', where 'X' is the trigger
- * and 'Y' is any string. These have opaque sub-strings.
- * The \B and \w escapes are handled in roff.c, roff_res().
- */
- case 'A':
- case 'b':
- case 'D':
- case 'R':
- case 'X':
- case 'Z':
- gly = ESCAPE_IGNORE;
- /* FALLTHROUGH */
- case 'o':
- if (**start == '\0')
- return ESCAPE_ERROR;
- if (gly == ESCAPE_ERROR)
- gly = ESCAPE_OVERSTRIKE;
- term = **start;
- *start = ++*end;
- break;
-
- /*
- * These escapes are of the form \X'N', where 'X' is the trigger
- * and 'N' resolves to a numerical expression.
- */
- case 'h':
- case 'H':
- case 'L':
- case 'l':
- case 'S':
- case 'v':
- case 'x':
- if (strchr(" %&()*+-./0123456789:<=>", **start)) {
- if ('\0' != **start)
- ++*end;
- return ESCAPE_ERROR;
- }
- switch ((*start)[-1]) {
- case 'h':
- gly = ESCAPE_HORIZ;
- break;
- case 'l':
- gly = ESCAPE_HLINE;
- break;
- default:
- gly = ESCAPE_IGNORE;
- break;
- }
- term = **start;
- *start = ++*end;
- break;
-
- /*
- * Special handling for the numbered character escape.
- * XXX Do any other escapes need similar handling?
- */
- case 'N':
- if ('\0' == **start)
- return ESCAPE_ERROR;
- (*end)++;
- if (isdigit((unsigned char)**start)) {
- *sz = 1;
- return ESCAPE_IGNORE;
- }
- (*start)++;
- while (isdigit((unsigned char)**end))
- (*end)++;
- *sz = *end - *start;
- if ('\0' != **end)
- (*end)++;
- return ESCAPE_NUMBERED;
-
- /*
- * Sizes get a special category of their own.
- */
- case 's':
- gly = ESCAPE_IGNORE;
-
- /* See +/- counts as a sign. */
- if ('+' == **end || '-' == **end || ASCII_HYPH == **end)
- *start = ++*end;
-
- switch (**end) {
- case '(':
- *start = ++*end;
- *sz = 2;
- break;
- case '[':
- *start = ++*end;
- term = ']';
- break;
- case '\'':
- *start = ++*end;
- term = '\'';
- break;
- case '3':
- case '2':
- case '1':
- *sz = (*end)[-1] == 's' &&
- isdigit((unsigned char)(*end)[1]) ? 2 : 1;
- break;
- default:
- *sz = 1;
- break;
- }
-
- break;
-
- /*
- * Several special characters can be encoded as
- * one-byte escape sequences without using \[].
- */
- case ' ':
- case '\'':
- case '-':
- case '.':
- case '0':
- case ':':
- case '_':
- case '`':
- case 'e':
- case '~':
- gly = ESCAPE_SPECIAL;
- /* FALLTHROUGH */
- default:
- if (gly == ESCAPE_ERROR)
- gly = ESCAPE_UNDEF;
- *start = --*end;
- *sz = 1;
- break;
- }
-
- /*
- * Read up to the terminating character,
- * paying attention to nested escapes.
- */
-
- if ('\0' != term) {
- while (**end != term) {
- switch (**end) {
- case '\0':
- return ESCAPE_ERROR;
- case '\\':
- (*end)++;
- if (ESCAPE_ERROR ==
- mandoc_escape(end, NULL, NULL))
- return ESCAPE_ERROR;
- break;
- default:
- (*end)++;
- break;
- }
- }
- *sz = (*end)++ - *start;
-
- /*
- * The file chars.c only provides one common list
- * of character names, but \[-] == \- is the only
- * one of the characters with one-byte names that
- * allows enclosing the name in brackets.
- */
- if (gly == ESCAPE_SPECIAL && *sz == 1 && **start != '-')
- return ESCAPE_ERROR;
- } else {
- assert(*sz > 0);
- if ((size_t)*sz > strlen(*start))
- return ESCAPE_ERROR;
- *end += *sz;
- }
-
- /* Run post-processors. */
-
- switch (gly) {
- case ESCAPE_FONT:
- gly = mandoc_font(*start, *sz);
- break;
- case ESCAPE_SPECIAL:
- if (**start == 'c') {
- if (*sz < 6 || *sz > 7 ||
- strncmp(*start, "char", 4) != 0 ||
- (int)strspn(*start + 4, "0123456789") + 4 < *sz)
- break;
- c = 0;
- for (i = 4; i < *sz; i++)
- c = 10 * c + ((*start)[i] - '0');
- if (c < 0x21 || (c > 0x7e && c < 0xa0) || c > 0xff)
- break;
- *start += 4;
- *sz -= 4;
- gly = ESCAPE_NUMBERED;
- break;
- }
-
- /*
- * Unicode escapes are defined in groff as \[u0000]
- * to \[u10FFFF], where the contained value must be
- * a valid Unicode codepoint. Here, however, only
- * check the length and range.
- */
- if (**start != 'u' || *sz < 5 || *sz > 7)
- break;
- if (*sz == 7 && ((*start)[1] != '1' || (*start)[2] != '0'))
- break;
- if (*sz == 6 && (*start)[1] == '0')
- break;
- if (*sz == 5 && (*start)[1] == 'D' &&
- strchr("89ABCDEF", (*start)[2]) != NULL)
- break;
- if ((int)strspn(*start + 1, "0123456789ABCDEFabcdef")
- + 1 == *sz)
- gly = ESCAPE_UNICODE;
- break;
- case ESCAPE_DEVICE:
- assert(*sz == 2 && (*start)[0] == '.' && (*start)[1] == 'T');
- break;
- default:
- break;
- }
-
- return gly;
-}
-
static int
a2time(time_t *t, const char *fmt, const char *p)
{