+++ /dev/null
-/*
-** m_getfld.c -- read/parse a message
-**
-** This code is Copyright (c) 2002, by the authors of nmh. See the
-** COPYRIGHT file in the root directory of the nmh distribution for
-** complete copyright information.
-*/
-
-#include <h/mh.h>
-#include <h/utils.h>
-#include <ctype.h>
-#include <sysexits.h>
-
-/*
-** This module has a long and checkered history.
-**
-** [ Here had been some history of delimiter problems in MMDF maildrops ... ]
-**
-** Unfortunately the speed issue finally caught up with us since this
-** routine is at the very heart of MH. To speed things up considerably, the
-** routine Eom() was made an auxilary function called by the macro eom().
-** Unless we are bursting a maildrop, the eom() macro returns FALSE saying
-** we aren't at the end of the message.
-**
-** [ ... and here had been some more of it. ]
-**
-**
-** ------------------------
-** (Written by Van Jacobson for the mh6 m_getfld, January, 1986):
-**
-** This routine was accounting for 60% of the cpu time used by most mh
-** programs. I spent a bit of time tuning and it now accounts for <10%
-** of the time used. Like any heavily tuned routine, it's a bit
-** complex and you want to be sure you understand everything that it's
-** doing before you start hacking on it. Let me try to emphasize
-** that: every line in this atrocity depends on every other line,
-** sometimes in subtle ways. You should understand it all, in detail,
-** before trying to change any part. If you do change it, test the
-** result thoroughly (I use a hand-constructed test file that exercises
-** all the ways a header name, header body, header continuation,
-** header-body separator, body line and body eom can align themselves
-** with respect to a buffer boundary). "Minor" bugs in this routine
-** result in garbaged or lost mail.
-**
-** If you hack on this and slow it down, I, my children and my
-** children's children will curse you.
-**
-** This routine gets used on two different types of files: normal,
-** single msg files and "packed" unix mailboxs (when used by inc).
-** The biggest impact of different file types is in "eom" testing. The
-** code has been carefully organized to test for eom at appropriate
-** times and at no other times (since the check is quite expensive).
-** I have tried to arrange things so that the eom check need only be
-** done on entry to this routine. Since an eom can only occur after a
-** newline, this is easy to manage for header fields. For the msg
-** body, we try to efficiently search the input buffer to see if
-** contains the eom delimiter. If it does, we take up to the
-** delimiter, otherwise we take everything in the buffer. (The change
-** to the body eom/copy processing produced the most noticeable
-** performance difference, particularly for "inc" and "show".)
-**
-** There are three qualitatively different things this routine busts
-** out of a message: field names, field text and msg bodies. Field
-** names are typically short (~8 char) and the loop that extracts them
-** might terminate on a colon, newline or max width. I considered
-** using a Vax "scanc" to locate the end of the field followed by a
-** "bcopy" but the routine call overhead on a Vax is too large for this
-** to work on short names. If Berkeley ever makes "inline" part of the
-** C optimiser (so things like "scanc" turn into inline instructions) a
-** change here would be worthwhile.
-**
-** Field text is typically 60 - 100 characters so there's (barely)
-** a win in doing a routine call to something that does a "locc"
-** followed by a "bmove". About 30% of the fields have continuations
-** (usually the 822 "received:" lines) and each continuation generates
-** another routine call. "Inline" would be a big win here, as well.
-**
-** Messages, as of this writing, seem to come in two flavors: small
-** (~1K) and long (>2K). Most messages have 400 - 600 bytes of headers
-** so message bodies average at least a few hundred characters.
-** Assuming your system uses reasonably sized stdio buffers (1K or
-** more), this routine should be able to remove the body in large
-** (>500 byte) chunks. The makes the cost of a call to "bcopy"
-** small but there is a premium on checking for the eom in packed
-** maildrops. The eom pattern is always a simple string so we can
-** construct an efficient pattern matcher for it (e.g., a Vax "matchc"
-** instruction). Some thought went into recognizing the start of
-** an eom that has been split across two buffers.
-**
-** This routine wants to deal with large chunks of data so, rather
-** than "getc" into a local buffer, it uses stdio's buffer. If
-** you try to use it on a non-buffered file, you'll get what you
-** deserve. This routine "knows" that struct FILEs have a _ptr
-** and a _cnt to describe the current state of the buffer and
-** it knows that _filbuf ignores the _ptr & _cnt and simply fills
-** the buffer. If stdio on your system doesn't work this way, you
-** may have to make small changes in this routine.
-**
-** This routine also "knows" that an EOF indication on a stream is
-** "sticky" (i.e., you will keep getting EOF until you reposition the
-** stream). If your system doesn't work this way it is broken and you
-** should complain to the vendor. As a consequence of the sticky
-** EOF, this routine will never return any kind of EOF status when
-** there is data in "name" or "buf").
-*/
-
-
-/*
-** static prototypes
-*/
-static int m_Eom(int, FILE *);
-static unsigned char *matchc(int, char *, int, char *);
-static unsigned char *locc(int, unsigned char *, unsigned char);
-
-#define eom(c,iob) (ismbox && \
- (((c) == *msg_delim && m_Eom(c,iob)) ||\
- (eom_action && (*eom_action)(c))))
-
-static unsigned char **pat_map;
-
-/*
-** This is a disgusting hack for "inc" so it can know how many
-** characters were stuffed in the buffer on the last call
-** (see comments in uip/scansbr.c).
-*/
-int msg_count = 0;
-
-int ismbox = FALSE;
-
-/*
-** The "full" delimiter string for a packed maildrop consists
-** of a newline followed by the actual delimiter. E.g., the
-** full string for a Unix maildrop would be: "\n\nFrom ".
-** "Fdelim" points to the start of the full string and is used
-** in the BODY case of the main routine to search the buffer for
-** a possible eom. Msg_delim points to the first character of
-** the actual delim. string (i.e., fdelim+1). Edelim
-** points to the 2nd character of actual delimiter string. It
-** is used in m_Eom because the first character of the string
-** has been read and matched before m_Eom is called.
-*/
-static char *msg_delim = "";
-
-static unsigned char *fdelim;
-static unsigned char *delimend;
-static int fdelimlen;
-static unsigned char *edelim;
-static int edelimlen;
-
-static int (*eom_action)(int) = NULL;
-
-#ifdef _FSTDIO
-# define _ptr _p /* Gag */
-# define _cnt _r /* Retch */
-# define _filbuf __srget /* Puke */
-# define DEFINED__FILBUF_TO_SOMETHING_SPECIFIC
-#endif
-
-#ifndef DEFINED__FILBUF_TO_SOMETHING_SPECIFIC
-extern int _filbuf(FILE*);
-#endif
-
-
-int
-m_getfld(int state, unsigned char *name, unsigned char *buf,
- int bufsz, FILE *iob)
-{
- unsigned char *bp, *cp, *ep, *sp;
- int cnt, c, i, j;
-
- if ((c = getc(iob)) < 0) {
- msg_count = 0;
- *buf = 0;
- return FILEEOF;
- }
- if (eom(c, iob)) {
- if (! eom_action) {
- /* flush null messages */
- while ((c = getc(iob)) >= 0 && eom(c, iob))
- ;
- if (c >= 0)
- ungetc(c, iob);
- }
- msg_count = 0;
- *buf = 0;
- return FILEEOF;
- }
-
- switch (state) {
- case FLD:
- if (c == '\n' || c == '-') {
- /* we hit the header/body separator */
- while (c != '\n' && (c = getc(iob)) >= 0)
- ;
-
- if (c < 0 || (c = getc(iob)) < 0 || eom(c, iob)) {
- if (!eom_action) {
- /* flush null messages */
- while ((c = getc(iob)) >= 0 && eom(c, iob))
- ;
- if (c >= 0)
- ungetc(c, iob);
- }
- msg_count = 0;
- *buf = 0;
- return FILEEOF;
- }
- state = BODY;
- goto body;
- }
- /*
- ** get the name of this component. take characters up
- ** to a ':', a newline or NAMESZ-1 characters,
- ** whichever comes first.
- */
- cp = name;
- i = NAMESZ - 1;
- for (;;) {
-#ifdef LINUX_STDIO
- bp = sp = (unsigned char *) iob->_IO_read_ptr - 1;
- j = (cnt = ((long) iob->_IO_read_end -
- (long) iob->_IO_read_ptr) + 1) < i ? cnt : i;
-#elif defined(__DragonFly__)
- bp = sp = (unsigned char *) ((struct __FILE_public *)iob)->_p - 1;
- j = (cnt = ((struct __FILE_public *)iob)->_r+1) < i ? cnt : i;
-#else
- bp = sp = (unsigned char *) iob->_ptr - 1;
- j = (cnt = iob->_cnt+1) < i ? cnt : i;
-#endif
- while (--j >= 0 && (c = *bp++) != ':' && c != '\n')
- *cp++ = c;
-
- j = bp - sp;
- if ((cnt -= j) <= 0) {
-#ifdef LINUX_STDIO
- iob->_IO_read_ptr = iob->_IO_read_end;
- if (__underflow(iob) == EOF) {
-#elif defined(__DragonFly__)
- if (__srget(iob) == EOF) {
-#else
- if (_filbuf(iob) == EOF) {
-#endif
- *cp = *buf = 0;
- advise(NULL, "eof encountered in field \"%s\"", name);
- return FMTERR;
- }
-#ifdef LINUX_STDIO
- iob->_IO_read_ptr++; /* NOT automatic in __underflow()! */
-#endif
- } else {
-#ifdef LINUX_STDIO
- iob->_IO_read_ptr = bp + 1;
-#elif defined(__DragonFly__)
- ((struct __FILE_public *)iob)->_p = bp + 1;
- ((struct __FILE_public *)iob)->_r = cnt - 1;
-#else
- iob->_ptr = bp + 1;
- iob->_cnt = cnt - 1;
-#endif
- }
- if (c == ':')
- break;
-
- /*
- ** something went wrong. possibilities are:
- ** . hit a newline (error)
- ** . got more than namesz chars. (error)
- ** . hit the end of the buffer. (loop)
- */
- if (c == '\n') {
- /*
- ** We hit the end of the line without
- ** seeing ':' to terminate the field name.
- ** This is usually (always?) spam. But,
- ** blowing up is lame, especially when
- ** scan(1)ing a folder with such messages.
- ** Pretend such lines are the first of
- ** the body (at least mutt also handles
- ** it this way).
- */
-
- /*
- ** See if buf can hold this line, since we
- ** were assuming we had a buffer of NAMESZ,
- ** not bufsz.
- */
- /* + 1 for the newline */
- if (bufsz < j + 1) {
- /*
- ** No, it can't. Oh well,
- ** guess we'll blow up.
- */
- *cp = *buf = 0;
- advise(NULL, "eol encountered in field \"%s\"", name);
- state = FMTERR;
- goto finish;
- }
- memcpy(buf, name, j - 1);
- buf[j - 1] = '\n';
- buf[j] = '\0';
- /*
- ** mhparse.c:get_content wants to find
- ** the position of the body start, but
- ** it thinks there's a blank line between
- ** the header and the body (naturally!),
- ** so seek back so that things line up
- ** even though we don't have that blank
- ** line in this case. Simpler parsers
- ** (e.g. mhl) get extra newlines, but
- ** that should be harmless enough, right?
- ** This is a corrupt message anyway.
- */
- fseek(iob, ftell(iob) - 2, SEEK_SET);
- return BODY;
- }
- if ((i -= j) <= 0) {
- *cp = *buf = 0;
- advise(NULL, "field name \"%s\" exceeds %d bytes", name, NAMESZ - 2);
- state = LENERR;
- goto finish;
- }
- }
-
- while (isspace(*--cp) && cp >= name)
- ;
- *++cp = 0;
- /* fall through */
-
- case FLDPLUS:
- /*
- ** get (more of) the text of a field. take
- ** characters up to the end of this field (newline
- ** followed by non-blank) or bufsz-1 characters.
- */
- cp = buf; i = bufsz-1;
- for (;;) {
-#ifdef LINUX_STDIO
- cnt = (long) iob->_IO_read_end - (long) iob->_IO_read_ptr;
- bp = (unsigned char *) --iob->_IO_read_ptr;
-#elif defined(__DragonFly__)
- cnt = ((struct __FILE_public *)iob)->_r++;
- bp = (unsigned char *) --((struct __FILE_public *)iob)->_p;
-#else
- cnt = iob->_cnt++;
- bp = (unsigned char *) --iob->_ptr;
-#endif
- c = cnt < i ? cnt : i;
- while ((ep = locc( c, bp, '\n' ))) {
- /*
- ** if we hit the end of this field,
- ** return.
- */
- if ((j = *++ep) != ' ' && j != '\t') {
-#ifdef LINUX_STDIO
- j = ep - (unsigned char *) iob->_IO_read_ptr;
- memcpy(cp, iob->_IO_read_ptr, j);
- iob->_IO_read_ptr = ep;
-#elif defined(__DragonFly__)
- j = ep - (unsigned char *) ((struct __FILE_public *)iob)->_p;
- memcpy(cp, ((struct __FILE_public *)iob)->_p, j);
- ((struct __FILE_public *)iob)->_p = ep;
- ((struct __FILE_public *)iob)->_r -= j;
-#else
- j = ep - (unsigned char *) iob->_ptr;
- memcpy(cp, iob->_ptr, j);
- iob->_ptr = ep;
- iob->_cnt -= j;
-#endif
- cp += j;
- state = FLD;
- goto finish;
- }
- c -= ep - bp;
- bp = ep;
- }
- /*
- ** end of input or dest buffer - copy what
- ** we've found.
- */
-#ifdef LINUX_STDIO
- c += bp - (unsigned char *) iob->_IO_read_ptr;
- memcpy(cp, iob->_IO_read_ptr, c);
-#elif defined(__DragonFly__)
- c += bp - (unsigned char *) ((struct __FILE_public *)iob)->_p;
- memcpy(cp, ((struct __FILE_public *)iob)->_p, c);
-#else
- c += bp - (unsigned char *) iob->_ptr;
- memcpy(cp, iob->_ptr, c);
-#endif
- i -= c;
- cp += c;
- if (i <= 0) {
- /* the dest buffer is full */
-#ifdef LINUX_STDIO
- iob->_IO_read_ptr += c;
-#elif defined(__DragonFly__)
- ((struct __FILE_public *)iob)->_r -= c;
- ((struct __FILE_public *)iob)->_p += c;
-#else
- iob->_cnt -= c;
- iob->_ptr += c;
-#endif
- state = FLDPLUS;
- break;
- }
- /*
- ** There's one character left in the input
- ** buffer. Copy it & fill the buffer.
- ** If the last char was a newline and the
- ** next char is not whitespace, this is
- ** the end of the field. Otherwise loop.
- */
- --i;
-#ifdef LINUX_STDIO
- *cp++ = j = *(iob->_IO_read_ptr + c);
- iob->_IO_read_ptr = iob->_IO_read_end;
- c = __underflow(iob);
- iob->_IO_read_ptr++; /* NOT automatic! */
-#elif defined(__DragonFly__)
- *cp++ =j = *(((struct __FILE_public *)iob)->_p + c);
- c = __srget(iob);
-#else
- *cp++ = j = *(iob->_ptr + c);
- c = _filbuf(iob);
-#endif
- if (c == EOF || ((j == '\0' || j == '\n')
- && c != ' ' && c != '\t')) {
- if (c != EOF) {
-#ifdef LINUX_STDIO
- --iob->_IO_read_ptr;
-#elif defined(__DragonFly__)
- --((struct __FILE_public *)iob)->_p;
- ++((struct __FILE_public *)iob)->_r;
-#else
- --iob->_ptr;
- ++iob->_cnt;
-#endif
- }
- state = FLD;
- break;
- }
- }
- break;
-
- case BODY:
- body:
- /*
- ** get the message body up to bufsz characters or
- ** the end of the message. Sleazy hack: if bufsz
- ** is negative we assume that we were called to
- ** copy directly into the output buffer and we
- ** don't add an eos.
- */
- i = (bufsz < 0) ? -bufsz : bufsz-1;
-#ifdef LINUX_STDIO
- bp = (unsigned char *) --iob->_IO_read_ptr;
- cnt = (long) iob->_IO_read_end - (long) iob->_IO_read_ptr;
-#elif defined(__DragonFly__)
- bp = (unsigned char *) --((struct __FILE_public *)iob)->_p;
- cnt = ++((struct __FILE_public *)iob)->_r;
-#else
- bp = (unsigned char *) --iob->_ptr;
- cnt = ++iob->_cnt;
-#endif
- c = (cnt < i ? cnt : i);
- if (ismbox && c > 1) {
- /*
- ** packed maildrop - only take up to the (possible)
- ** start of the next message. This "matchc" should
- ** probably be a Boyer-Moore matcher for non-vaxen,
- ** particularly since we have the alignment table
- ** all built for the end-of-buffer test (next).
- ** But our vax timings indicate that the "matchc"
- ** instruction is 50% faster than a carefully coded
- ** B.M. matcher for most strings. (So much for
- ** elegant algorithms vs. brute force.) Since I
- ** (currently) run MH on a vax, we use the matchc
- ** instruction. --vj
- */
- if ((ep = matchc( fdelimlen, fdelim, c, bp )))
- c = ep - bp + 1;
- else {
- /*
- ** There's no delim in the buffer but
- ** there may be a partial one at the end.
- ** If so, we want to leave it so the "eom"
- ** check on the next call picks it up. Use a
- ** modified Boyer-Moore matcher to make this
- ** check relatively cheap. The first "if"
- ** figures out what position in the pattern
- ** matches the last character in the buffer.
- ** The inner "while" matches the pattern
- ** against the buffer, backwards starting
- ** at that position. Note that unless the
- ** buffer ends with one of the characters
- ** in the pattern (excluding the first
- ** and last), we do only one test.
- */
- ep = bp + c - 1;
- if ((sp = pat_map[*ep])) {
- do {
- /*
- ** This if() is true unless
- ** (a) the buffer is too
- ** small to contain this
- ** delimiter prefix,
- ** or (b) it contains
- ** exactly enough chars for
- ** the delimiter prefix.
- ** For case (a) obviously we
- ** aren't going to match.
- ** For case (b), if the
- ** buffer really contained
- ** exactly a delim prefix,
- ** then the m_eom call
- ** at entry should have
- ** found it. Thus it's
- ** not a delim and we know
- ** we won't get a match.
- */
- if (((sp - fdelim) + 2) <= c) {
- cp = sp;
- /*
- ** Unfortunately although fdelim has a preceding NUL
- ** we can't use this as a sentinel in case the buffer
- ** contains a NUL in exactly the wrong place (this
- ** would cause us to run off the front of fdelim).
- */
- while (*--ep == *--cp)
- if (cp < fdelim)
- break;
- if (cp < fdelim) {
- /* we matched the entire delim prefix,
- ** so only take the buffer up to there.
- ** we know ep >= bp -- check above prevents underrun
- */
- c = (ep - bp) + 2;
- break;
- }
- }
- /* try matching one less char of delim string */
- ep = bp + c - 1;
- } while (--sp > fdelim);
- }
- }
- }
- memcpy( buf, bp, c );
-#ifdef LINUX_STDIO
- iob->_IO_read_ptr += c;
-#elif defined(__DragonFly__)
- ((struct __FILE_public *)iob)->_r -= c;
- ((struct __FILE_public *)iob)->_p += c;
-#else
- iob->_cnt -= c;
- iob->_ptr += c;
-#endif
- if (bufsz < 0) {
- msg_count = c;
- return (state);
- }
- cp = buf + c;
- break;
-
- default:
- adios(EX_SOFTWARE, NULL, "m_getfld() called with bogus state of %d", state);
- }
-finish:
- *cp = 0;
- msg_count = cp - buf;
- return (state);
-}
-
-
-void
-thisisanmbox(FILE *iob)
-{
- int c;
- char text[10];
- char *cp;
- char *delimstr;
-
- c = getc(iob);
- if (feof(iob)) {
- return;
- }
- ungetc(c, iob);
-
- /*
- ** Figure out what the message delimitter string is for this
- ** maildrop. (This used to be part of m_Eom but I didn't like
- ** the idea of an "if" statement that could only succeed on the
- ** first call to m_Eom getting executed on each call, i.e., at
- ** every newline in the message).
- **
- ** If the first line of the maildrop is a Unix "From " line, we
- ** say the style is MBOX and eat the rest of the line. Otherwise
- ** abort.
- */
-
- if (fread(text, sizeof(*text), 5, iob) != 5) {
- adios(EX_IOERR, NULL, "Read error");
- }
- if (strncmp(text, "From ", 5)!=0) {
- adios(EX_USAGE, NULL, "No Unix style (mbox) maildrop.");
- }
- ismbox = TRUE;
- delimstr = "\nFrom ";
- while ((c = getc(iob)) != '\n' && c >= 0) {
- continue;
- }
- c = strlen(delimstr);
- fdelim = (unsigned char *) mh_xmalloc((size_t) (c + 3));
- *fdelim++ = '\0';
- *fdelim = '\n';
- msg_delim = (char *)fdelim+1;
- edelim = (unsigned char *)msg_delim+1;
- fdelimlen = c + 1;
- edelimlen = c - 1;
- strcpy(msg_delim, delimstr);
- delimend = (unsigned char *)msg_delim + edelimlen;
- if (edelimlen <= 1)
- adios(EX_DATAERR, NULL, "maildrop delimiter must be at least 2 bytes");
- /*
- ** build a Boyer-Moore end-position map for the matcher in m_getfld.
- ** N.B. - we don't match just the first char (since it's the newline
- ** separator) or the last char (since the matchc would have found it
- ** if it was a real delim).
- */
- pat_map = (unsigned char **) mh_xcalloc(256, sizeof(unsigned char *));
-
- for (cp = (char *) fdelim + 1; cp < (char *) delimend; cp++ )
- pat_map[(unsigned char)*cp] = (unsigned char *) cp;
-}
-
-
-/*
-** test for msg delimiter string
-*/
-
-static int
-m_Eom(int c, FILE *iob)
-{
- long pos = 0L;
- int i;
- char text[10];
-
- pos = ftell(iob);
- if ((i = fread(text, sizeof *text, edelimlen, iob)) != edelimlen ||
- (strncmp(text, (char *)edelim, edelimlen)!=0)) {
- if (i == 0 && ismbox)
- /*
- ** the final newline in the (brain damaged) unix-format
- ** maildrop is part of the delimitter - delete it.
- */
- return 1;
-
- fseek(iob, (long)(pos-1), SEEK_SET);
- getc(iob); /* should be OK */
- return 0;
- }
-
- if (ismbox) {
- while ((c = getc(iob)) != '\n' && c >= 0) {
- continue;
- }
- }
-
- return 1;
-}
-
-
-static unsigned char *
-matchc(int patln, char *pat, int strln, char *str)
-{
- char *es = str + strln - patln;
- char *sp;
- char *pp;
- char *ep = pat + patln;
- char pc = *pat++;
-
- for(;;) {
- while (pc != *str++)
- if (str > es)
- return 0;
- if (str > es+1)
- return 0;
- sp = str; pp = pat;
- while (pp < ep && *sp++ == *pp)
- pp++;
- if (pp >= ep)
- return ((unsigned char *)--str);
- }
-}
-
-
-/*
-** Locate character "term" in the next "cnt" characters of "src".
-** If found, return its address, otherwise return 0.
-*/
-
-static unsigned char *
-locc(int cnt, unsigned char *src, unsigned char term)
-{
- while (*src++ != term && --cnt > 0)
- ;
-
- return (cnt > 0 ? --src : (unsigned char *)0);
-}
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