X-Git-Url: https://diplodocus.org/git/nmh/blobdiff_plain/d3e11c5e949fe00326e16f29191cf5d13fad0404..c576ad2674c37a1c63f004c71049998f38854c64:/sbr/m_getfld.c diff --git a/sbr/m_getfld.c b/sbr/m_getfld.c index 683db175..f5fa9a4e 100644 --- a/sbr/m_getfld.c +++ b/sbr/m_getfld.c @@ -8,6 +8,7 @@ #include #include #include +#include /* Purpose @@ -59,10 +60,13 @@ Usage ===== - m_getfld_state_t gstate = 0; - ... - int state = m_getfld (&gstate, ...); - ... + m_getfld_state_t gstate; + + gstate = m_getfld_state_init(mailfp); + Perhaps m_getfld_track_filepos2(&gstate); + ... + state = m_getfld2(&gstate, ...); + ...Repeat until finished with mailfp. m_getfld_state_destroy (&gstate); The state is retained internally by gstate. To reset its state to FLD: @@ -90,7 +94,7 @@ To speed things up considerably, the routine Eom() was made an auxiliary 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 + the eom() macro returns false saying we aren't at the end of the message. The next thing to do is to read the mts.conf file and initialize @@ -200,11 +204,20 @@ /* * static prototypes */ +static void Ungetc(m_getfld_state_t s); static int m_Eom (m_getfld_state_t); #define eom(c,s) (s->msg_style != MS_DEFAULT && \ ((c) == *s->msg_delim && m_Eom(s))) +/* + * Maildrop styles + */ +#define MS_DEFAULT 0 /* default (one msg per file) */ +#define MS_UNKNOWN 1 /* type not known yet */ +#define MS_MBOX 2 /* Unix-style "from" lines */ +#define MS_MMDF 3 /* string MMDF_DELIM */ + /* This replaces the old approach, with its direct access to stdio * internals. It uses one fread() to load a buffer that we manage. * @@ -219,53 +232,88 @@ static int m_Eom (m_getfld_state_t); #define MAX_DELIMITER_SIZE 5 struct m_getfld_state { + /* The file to read from; I/O block. Caller keeps passing it after + * initialisation due to historic interface so it keeps getting + * updated, presumably to the same value. */ + FILE *iob; + + /* Holds content of iob. */ char msg_buf[2 * MSG_INPUT_SIZE + MAX_DELIMITER_SIZE]; + /* Points to the next byte to read from msg_buf. */ char *readpos; - char *end; /* One past the last character read in. */ - /* The following support tracking of the read position in the - input file stream so that callers can interleave m_getfld() - calls with ftell() and fseek(). bytes_read replaces the old - m_getfld() msg_count global. last_caller_pos is stored when - leaving m_getfld()/m_unknown(), then checked on the next entry. - last_internal_pos is used to remember the position used - internally by m_getfld() (read_more(), actually). */ + /* Points to just after the last valid byte in msg_buf. If readpos + * equals end then msg_buf is empty. */ + char *end; + + /* Whether the caller intends to ftell(3)/fseek(3) iob's position, + * and thus whether m_getfld() needs to detect that and compensate. */ + int track_filepos; + /* Position in iob given what's been consumed ready for returning to + * the caller. Further than this may have been read into msg_buf. */ + off_t total_bytes_read; + /* Bytes of iob consumed during this call. */ off_t bytes_read; - off_t total_bytes_read; /* by caller, not necessarily from input file */ + /* What fseeko(3) tells us iob's position is having just explicitly + * set it to total_bytes_read. Surely always the same? */ off_t last_caller_pos; + /* Saved position in iob from filling msg_buf, prior to returning. */ off_t last_internal_pos; - FILE *iob; - char **pat_map; + /* One of the MS_* macros tracking the type of iob's content and + * thus if it's a single email, or several with delimeters. Default + * is MS_DEFAULT. */ int msg_style; - /* - * 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. - */ + + /* The message delimeter if iob has multiple emails, else NULL. For + * MS_MBOX it's the string that separates two emails, "\nFrom ", + * i.e. the terminating blank line of the previous email, and the + * starting From_ line of the next, but for MS_MMDF it's + * "\001\001\001\001\n" that may start or terminate an email. */ char *msg_delim; - char *fdelim; + /* The last non-NUL char of msg_delim. */ char *delimend; + /* When searching for msg_delim after an email, it's only of + * interest at the start of the line, i.e. when preceded by a + * linefeed. fdelim points to msg_delim[-1] that contains '\n' so + * it can be used as the needle. */ + char *fdelim; + /* strlen(fdelim). */ int fdelimlen; + /* The second char of msg_delim. Used when the first char has + * already been matched to test the rest. */ char *edelim; + /* strlen(edelim). */ int edelimlen; + /* The relationship between all of these pointers and lengths for + * the two possible msg_delim values. + * + * "\0\n\nFrom \0" 9 "\0\n\001\001\001\001\n\0" 8 + * | || | | | | | + * | || s->delimend | | | s->delimend + * | || | | | + * | |s->edelim s->edelimlen=5 | | s->edelim s->edelimlen=4 + * | | | | + * | s->msg_delim | s->msg_delim + * | | + * s->fdelim s->fdelimlen=7 s->fdelim s->fdelimlen=6 + */ + + /* Maps all the bytes of msg_delim, apart from the last two, + * including the NUL, onto the last position in msg_delim where they + * occur. Bytes not present are NULL. */ + char **pat_map; + + /* The parser's current state. Also returned to the caller, amongst + * other possible values, to indicate the token consumed. One of + * FLD, FLDPLUS, BODY, or FILEEOF. */ int state; - int track_filepos; }; -static -void -m_getfld_state_init (m_getfld_state_t *gstate, FILE *iob) { +m_getfld_state_t m_getfld_state_init(FILE *iob) +{ m_getfld_state_t s; NEW(s); - *gstate = s; s->readpos = s->end = s->msg_buf; s->bytes_read = s->total_bytes_read = 0; s->last_caller_pos = s->last_internal_pos = 0; @@ -277,9 +325,11 @@ m_getfld_state_init (m_getfld_state_t *gstate, FILE *iob) { s->fdelimlen = s->edelimlen = 0; s->state = FLD; s->track_filepos = 0; + + return s; } -/* scan() needs to force a state an initial state of FLD for each message. */ +/* scan() needs to force an initial state of FLD for each message. */ void m_getfld_state_reset (m_getfld_state_t *gstate) { if (*gstate) { @@ -293,12 +343,21 @@ m_getfld_state_reset (m_getfld_state_t *gstate) { void m_getfld_track_filepos (m_getfld_state_t *gstate, FILE *iob) { if (! *gstate) { - m_getfld_state_init (gstate, iob); + *gstate = m_getfld_state_init(iob); } (*gstate)->track_filepos = 1; } +/* m_getfld_track_filepos() with the existing iob. */ +void m_getfld_track_filepos2(m_getfld_state_t *gstate) +{ + if (!*gstate) + adios(NULL, "m_getfld_track_filepos2 without gstate"); + + m_getfld_track_filepos(gstate, (*gstate)->iob); +} + void m_getfld_state_destroy (m_getfld_state_t *gstate) { m_getfld_state_t s = *gstate; @@ -348,7 +407,7 @@ enter_getfld (m_getfld_state_t *gstate, FILE *iob) { off_t pos_movement; if (! *gstate) { - m_getfld_state_init (gstate, iob); + *gstate = m_getfld_state_init(iob); } s = *gstate; s->bytes_read = 0; @@ -364,7 +423,8 @@ enter_getfld (m_getfld_state_t *gstate, FILE *iob) { if (!s->track_filepos) return; - pos = ftello(iob); + if ((pos = ftello(iob)) == -1) + adios("getfld's iob", "failed to get offset on entry"); if (pos == 0 && s->last_internal_pos == 0) return; @@ -393,11 +453,15 @@ enter_getfld (m_getfld_state_t *gstate, FILE *iob) { s->total_bytes_read += pos_movement; pos = s->last_internal_pos; } else { + off_t off; size_t num_read; /* This seek skips past an integral number of chunks of size MSG_INPUT_SIZE. */ - fseeko (iob, pos/MSG_INPUT_SIZE * MSG_INPUT_SIZE, SEEK_SET); + off = pos / MSG_INPUT_SIZE * MSG_INPUT_SIZE; + if (fseeko(iob, off, SEEK_SET) == -1) + adios("getfld's iob", "failed to set offset to skip: " + "%" PRIdMAX, (intmax_t)off); num_read = fread (s->msg_buf, 1, MSG_INPUT_SIZE, iob); s->readpos = s->msg_buf + pos % MSG_INPUT_SIZE; s->end = s->msg_buf + num_read; @@ -405,7 +469,9 @@ enter_getfld (m_getfld_state_t *gstate, FILE *iob) { } } - fseeko (iob, pos, SEEK_SET); + if (fseeko(iob, pos, SEEK_SET) == -1) + adios("getfld's iob", "failed to set offset on entry: %" PRIdMAX, + (intmax_t)pos); } static void @@ -414,27 +480,34 @@ leave_getfld (m_getfld_state_t s) { if (s->track_filepos) { /* Save the internal file position that we use for the input buffer. */ - s->last_internal_pos = ftello (s->iob); + if ((s->last_internal_pos = ftello(s->iob)) == -1) + adios("getfld's iob", "failed to get offset before seek"); /* Set file stream position so that callers can use ftell(). */ - fseeko (s->iob, s->total_bytes_read, SEEK_SET); - s->last_caller_pos = ftello (s->iob); + if (fseeko(s->iob, s->total_bytes_read, SEEK_SET) == -1) + adios("getfld's iob", "failed to set offset: %" PRIdMAX, + (intmax_t)s->total_bytes_read); + + s->last_caller_pos = s->total_bytes_read; } } static size_t read_more (m_getfld_state_t s) { - /* Retain at least edelimlen characters that have already been - read so that we can back up to them in m_Eom(). */ - ssize_t retain = s->edelimlen; + /* Retain at least edelimlen characters that have already been read, + if at least edelimlen have been read, so that we can back up to them + in m_Eom(). */ + ssize_t retain = s->end - s->msg_buf < s->edelimlen ? 0 : s->edelimlen; size_t num_read; - if (retain < s->end - s->readpos) - retain = s->end - s->readpos; - assert (retain <= s->readpos - s->msg_buf); + if (retain > 0) { + if (retain < s->end - s->readpos) + retain = s->end - s->readpos; + assert (retain <= s->readpos - s->msg_buf); - /* Move what we want to retain at end of the buffer to the beginning. */ - memmove (s->msg_buf, s->readpos - retain, retain); + /* Move what we want to retain at end of the buffer to the beginning. */ + memmove (s->msg_buf, s->readpos - retain, retain); + } s->readpos = s->msg_buf + retain; num_read = fread (s->readpos, 1, MSG_INPUT_SIZE, s->iob); @@ -443,9 +516,8 @@ read_more (m_getfld_state_t s) { return num_read; } -/* The return values of the following functions are a bit - subtle. They can return 0x00 - 0xff as a valid character, - but EOF is typically 0xffffffff. */ +/* Return the next character consumed from the input, fetching more of + * the input for the buffer if required, or EOF on end of file. */ static int Getc (m_getfld_state_t s) { if ((s->end - s->readpos < 1 && read_more (s) == 0) || @@ -456,21 +528,29 @@ Getc (m_getfld_state_t s) { return (unsigned char)*s->readpos++; } +/* Return the next character that Getc() would return, which may be EOF. */ static int -Peek (m_getfld_state_t s) { - if (s->end - s->readpos < 1 && read_more (s) == 0) { - return EOF; - } - return s->readpos < s->end ? (unsigned char) *s->readpos : EOF; +Peek (m_getfld_state_t s) +{ + int c; + + c = Getc(s); + if (c != EOF) + Ungetc(s); + + return c; } -static int -Ungetc (int c, m_getfld_state_t s) { - if (s->readpos == s->msg_buf) { - return EOF; - } - --s->bytes_read; - return *--s->readpos = (unsigned char) c; +/* If there's room, undo the consumption of one character from msg_buf, + * rewinding so it's read next, else die. */ +static void +Ungetc(m_getfld_state_t s) +{ + if (s->readpos == s->msg_buf) + adios(NULL, "Ungetc() at start of message buffer."); + + s->readpos--; + s->bytes_read--; } @@ -496,7 +576,7 @@ m_getfld (m_getfld_state_t *gstate, char name[NAMESZ], char *buf, int *bufsz, ; if (c != EOF) - Ungetc(c, s); + Ungetc(s); *bufsz = *buf = 0; leave_getfld (s); return s->state = FILEEOF; @@ -514,7 +594,7 @@ m_getfld (m_getfld_state_t *gstate, char name[NAMESZ], char *buf, int *bufsz, while ((c = Getc(s)) != EOF && eom (c, s)) ; if (c != EOF) - Ungetc(c, s); + Ungetc(s); *bufsz = *buf = 0; leave_getfld (s); return s->state = FILEEOF; @@ -681,6 +761,9 @@ m_getfld (m_getfld_state_t *gstate, char name[NAMESZ], char *buf, int *bufsz, char *ep; if ((ep = memmem(bp, c, s->fdelim, s->fdelimlen))) + /* Plus one to nab the '\n' that starts fdelim as + * that ends the previous line; it isn't part of + * msg_delim. */ c = ep - bp + 1; else { /* @@ -698,7 +781,7 @@ m_getfld (m_getfld_state_t *gstate, char name[NAMESZ], char *buf, int *bufsz, */ char *sp; - ep = bp + c - 1; + ep = bp + c - 1; /* The last byte. */ if ((sp = s->pat_map[(unsigned char) *ep])) { do { /* This if() is true unless (a) the buffer is too @@ -760,6 +843,16 @@ m_getfld (m_getfld_state_t *gstate, char name[NAMESZ], char *buf, int *bufsz, } +/* m_getfld() with the existing iob. */ +int m_getfld2(m_getfld_state_t *gstate, char name[NAMESZ], char *buf, int *bufsz) +{ + if (!*gstate) + adios(NULL, "m_getfld2 without gstate"); + + return m_getfld(gstate, name, buf, bufsz, (*gstate)->iob); +} + + void m_unknown(m_getfld_state_t *gstate, FILE *iob) { @@ -810,6 +903,10 @@ m_unknown(m_getfld_state_t *gstate, FILE *iob) s->msg_style = MS_MMDF; } + /* "\nFrom \0" 7 "\001\001\001\001\n\0" 6 + * | | + * delimstr c=6 delimstr c=5 + */ c = strlen (delimstr); s->fdelim = mh_xmalloc (c + 3); /* \0, \n, delimstr, \0 */ *s->fdelim++ = '\0'; @@ -823,24 +920,6 @@ m_unknown(m_getfld_state_t *gstate, FILE *iob) if (s->edelimlen <= 1) adios (NULL, "maildrop delimiter must be at least 2 bytes"); - /* Now malloc'd memory at s->fdelim-1 is referenced several times, - * containing a copy of the string constant from delimstr. - * - * "\nFrom \0" 7 "\001\001\001\001\n\0" 6 - * | | - * delimstr c=6 delimstr c=5 - * - * "\0\n\nFrom \0" 9 "\0\n\001\001\001\001\n\0" 8 - * | || | | | | | - * | || s->delimend | | | s->delimend - * | || | | | - * | |s->edelim s->edelimlen=5 | | s->edelim s->edelimlen=4 - * | | | | - * | s->msg_delim | s->msg_delim - * | | - * s->fdelim s->fdelimlen=7 s->fdelim s->fdelimlen=6 - */ - /* * 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 @@ -857,13 +936,23 @@ m_unknown(m_getfld_state_t *gstate, FILE *iob) while ((c = Getc(s)) != EOF && eom (c, s)) ; if (c != EOF) - Ungetc(c, s); + Ungetc(s); } leave_getfld (s); } +/* m_unknown() with the existing iob. */ +void m_unknown2(m_getfld_state_t *gstate) +{ + if (!*gstate) + adios(NULL, "m_unknown2 without gstate"); + + m_unknown(gstate, (*gstate)->iob); +} + + /* * test for msg delimiter string */ @@ -874,12 +963,16 @@ m_Eom (m_getfld_state_t s) int i; char text[MAX_DELIMITER_SIZE]; char *cp; + int adjust = 1; for (i = 0, cp = text; i < s->edelimlen; ++i, ++cp) { - if ((*cp = Getc (s)) == EOF) { + int c2; + + if ((c2 = Getc (s)) == EOF) { *cp = '\0'; break; } + *cp = c2; } if (i != s->edelimlen || @@ -891,11 +984,19 @@ m_Eom (m_getfld_state_t s) return 1; } + if (i <= 2 && s->msg_style == MS_MBOX && + i != s->edelimlen && ! strncmp(text, s->fdelim, i)) { + /* If all or part of fdelim appeared at the end of the file, + back up even more so that the bytes are included in the + message. */ + adjust = 2; + } + /* Did not find delimiter, so restore the read position. Note that on input, a character had already been read with Getc(). It will be unget by m_getfld () on return. */ - s->readpos -= s->bytes_read - 1; - s->bytes_read = 1; + s->readpos -= s->bytes_read - adjust; + s->bytes_read = adjust; return 0; }