/*++ /* NAME /* smtp_stream 3 /* SUMMARY /* smtp stream I/O support /* SYNOPSIS /* #include <smtp_stream.h> /* /* void smtp_timeout_setup(stream, timeout) /* VSTREAM *stream; /* int timeout; /* /* void smtp_printf(stream, format, ...) /* VSTREAM *stream; /* const char *format; /* /* void smtp_flush(stream) /* VSTREAM *stream; /* /* int smtp_fgetc(stream) /* VSTREAM *stream; /* /* int smtp_get(vp, stream, maxlen) /* VSTRING *vp; /* VSTREAM *stream; /* ssize_t maxlen; /* /* void smtp_fputs(str, len, stream) /* const char *str; /* ssize_t len; /* VSTREAM *stream; /* /* void smtp_fwrite(str, len, stream) /* const char *str; /* ssize_t len; /* VSTREAM *stream; /* /* void smtp_fputc(ch, stream) /* int ch; /* VSTREAM *stream; /* /* void smtp_vprintf(stream, format, ap) /* VSTREAM *stream; /* char *format; /* va_list ap; /* DESCRIPTION /* This module reads and writes text records delimited by CR LF, /* with error detection: timeouts or unexpected end-of-file. /* A trailing CR LF is added upon writing and removed upon reading. /* /* smtp_timeout_setup() arranges for a time limit on the smtp read /* and write operations described below. /* This routine alters the behavior of streams as follows: /* .IP \(bu /* The read/write timeout is set to the specified value. /* .IP \f(bu /* The stream is configured to use double buffering. /* .IP \f(bu /* The stream is configured to enable exception handling. /* .PP /* smtp_printf() formats its arguments and writes the result to /* the named stream, followed by a CR LF pair. The stream is NOT flushed. /* Long lines of text are not broken. /* /* smtp_flush() flushes the named stream. /* /* smtp_fgetc() reads one character from the named stream. /* /* smtp_get() reads the named stream up to and including /* the next LF character and strips the trailing CR LF. The /* \fImaxlen\fR argument limits the length of a line of text, /* and protects the program against running out of memory. /* Specify a zero bound to turn off bounds checking. /* The result is the last character read, or VSTREAM_EOF. /* /* smtp_fputs() writes its string argument to the named stream. /* Long strings are not broken. Each string is followed by a /* CR LF pair. The stream is not flushed. /* /* smtp_fwrite() writes its string argument to the named stream. /* Long strings are not broken. No CR LF is appended. The stream /* is not flushed. /* /* smtp_fputc() writes one character to the named stream. /* The stream is not flushed. /* /* smtp_vprintf() is the machine underneath smtp_printf(). /* DIAGNOSTICS /* .fi /* .ad /* In case of error, a vstream_longjmp() call is performed to the /* context specified with vstream_setjmp(). /* Error codes passed along with vstream_longjmp() are: /* .IP SMTP_ERR_EOF /* An I/O error happened, or the peer has disconnected unexpectedly. /* .IP SMTP_ERR_TIME /* The time limit specified to smtp_timeout_setup() was exceeded. /* .PP /* Additional error codes that may be used by applications: /* .IP SMTP_ERR_QUIET /* Perform silent cleanup; the error was already reported by /* the application. /* This error is never generated by the smtp_stream(3) module, but /* is defined for application-specific use. /* .IP SMTP_ERR_NONE /* A non-error code that makes setjmp()/longjmp() convenient /* to use. /* BUGS /* The timeout deadline affects all I/O on the named stream, not /* just the I/O done on behalf of this module. /* /* The timeout deadline overwrites any previously set up state on /* the named stream. /* LICENSE /* .ad /* .fi /* The Secure Mailer license must be distributed with this software. /* AUTHOR(S) /* Wietse Venema /* IBM T.J. Watson Research /* P.O. Box 704 /* Yorktown Heights, NY 10598, USA /*--*/ /* System library. */ #include <sys_defs.h> #include <sys/socket.h> #include <sys/time.h> #include <setjmp.h> #include <stdlib.h> #include <stdarg.h> #include <unistd.h> #include <string.h> /* FD_ZERO() needs bzero() prototype */ #include <errno.h> /* Utility library. */ #include <vstring.h> #include <vstream.h> #include <vstring_vstream.h> #include <msg.h> #include <iostuff.h> /* Application-specific. */ #include "smtp_stream.h" /* smtp_timeout_reset - reset per-stream timeout flag */ static void smtp_timeout_reset(VSTREAM *stream) { vstream_clearerr(stream); } /* smtp_timeout_detect - test the per-stream timeout flag */ static void smtp_timeout_detect(VSTREAM *stream) { if (vstream_ftimeout(stream)) vstream_longjmp(stream, SMTP_ERR_TIME); } /* smtp_timeout_setup - configure timeout trap */ void smtp_timeout_setup(VSTREAM *stream, int maxtime) { vstream_control(stream, VSTREAM_CTL_DOUBLE, VSTREAM_CTL_TIMEOUT, maxtime, VSTREAM_CTL_EXCEPT, VSTREAM_CTL_END); } /* smtp_flush - flush stream */ void smtp_flush(VSTREAM *stream) { int err; /* * Do the I/O, protected against timeout. */ smtp_timeout_reset(stream); err = vstream_fflush(stream); smtp_timeout_detect(stream); /* * See if there was a problem. */ if (err != 0) { if (msg_verbose) msg_info("smtp_flush: EOF"); vstream_longjmp(stream, SMTP_ERR_EOF); } } /* smtp_vprintf - write one line to SMTP peer */ void smtp_vprintf(VSTREAM *stream, const char *fmt, va_list ap) { int err; /* * Do the I/O, protected against timeout. */ smtp_timeout_reset(stream); vstream_vfprintf(stream, fmt, ap); vstream_fputs("\r\n", stream); err = vstream_ferror(stream); smtp_timeout_detect(stream); /* * See if there was a problem. */ if (err != 0) { if (msg_verbose) msg_info("smtp_vprintf: EOF"); vstream_longjmp(stream, SMTP_ERR_EOF); } } /* smtp_printf - write one line to SMTP peer */ void smtp_printf(VSTREAM *stream, const char *fmt,...) { va_list ap; va_start(ap, fmt); smtp_vprintf(stream, fmt, ap); va_end(ap); } /* smtp_fgetc - read one character from SMTP peer */ int smtp_fgetc(VSTREAM *stream) { int ch; /* * Do the I/O, protected against timeout. */ smtp_timeout_reset(stream); ch = VSTREAM_GETC(stream); smtp_timeout_detect(stream); /* * See if there was a problem. */ if (vstream_feof(stream) || vstream_ferror(stream)) { if (msg_verbose) msg_info("smtp_fgetc: EOF"); vstream_longjmp(stream, SMTP_ERR_EOF); } return (ch); } /* APPLE - RFC 3030 */ static int smtp_get_full(VSTRING *vp, VSTREAM *stream, ssize_t bound, int binary, int expect_eof) { int last_char; int next_char; /* * It's painful to do I/O with records that may span multiple buffers. * Allow for partial long lines (we will read the remainder later) and * allow for lines ending in bare LF. The idea is to be liberal in what * we accept, strict in what we send. * * XXX 2821: Section 4.1.1.4 says that an SMTP server must not recognize * bare LF as record terminator. */ smtp_timeout_reset(stream); last_char = (bound == 0 ? vstring_get(vp, stream) : vstring_get_bound(vp, stream, bound)); switch (last_char) { /* * Do some repair in the rare case that we stopped reading in the * middle of the CRLF record terminator. */ case '\r': if ((next_char = VSTREAM_GETC(stream)) == '\n') { VSTRING_ADDCH(vp, '\n'); last_char = '\n'; /* FALLTRHOUGH */ } else { if (next_char != VSTREAM_EOF) vstream_ungetc(stream, next_char); break; } /* * Strip off the record terminator: either CRLF or just bare LF. * * XXX RFC 2821 disallows sending bare CR everywhere. We remove bare CR * if received before CRLF, and leave it alone otherwise. */ case '\n': /* APPLE - RFC 3030 */ if (binary) { /* do not strip extra CRs. strip and return LF if and only if CRLF. */ if (VSTRING_LEN(vp) > 1 && vstring_end(vp)[-2] == '\r') vstring_truncate(vp, VSTRING_LEN(vp) - 2); else last_char = 0; VSTRING_TERMINATE(vp); break; } vstring_truncate(vp, VSTRING_LEN(vp) - 1); while (VSTRING_LEN(vp) > 0 && vstring_end(vp)[-1] == '\r') vstring_truncate(vp, VSTRING_LEN(vp) - 1); VSTRING_TERMINATE(vp); /* * Partial line: just read the remainder later. If we ran into EOF, * the next test will deal with it. */ default: break; } smtp_timeout_detect(stream); /* APPLE - RFC 3030 */ if (expect_eof && vstream_feof(stream)) return last_char; /* * EOF is bad, whether or not it happens in the middle of a record. Don't * allow data that was truncated because of EOF. */ if (vstream_feof(stream) || vstream_ferror(stream)) { if (msg_verbose) msg_info("smtp_get: EOF"); vstream_longjmp(stream, SMTP_ERR_EOF); } return (last_char); } /* smtp_get - read one line from SMTP peer */ int smtp_get(VSTRING *vp, VSTREAM *stream, ssize_t bound) { return smtp_get_full(vp, stream, bound, 0, 0); } /* APPLE - RFC 3030 */ int smtp_get_to_eof(VSTRING *vp, VSTREAM *stream, ssize_t bound) { return smtp_get_full(vp, stream, bound, 0, 1); } int smtp_get_binary_to_eof(VSTRING *vp, VSTREAM *stream, ssize_t bound) { return smtp_get_full(vp, stream, bound, 1, 1); } /* APPLE - RFC 3030 */ void smtp_discard(VSTREAM *stream, off_t size) { if (size <= 0) return; smtp_timeout_reset(stream); while (VSTREAM_GETC(stream) != VSTREAM_EOF && --size > 0) ; smtp_timeout_detect(stream); if (vstream_feof(stream) || vstream_ferror(stream)) vstream_longjmp(stream, SMTP_ERR_EOF); } /* smtp_fputs - write one line to SMTP peer */ void smtp_fputs(const char *cp, ssize_t todo, VSTREAM *stream) { ssize_t err; if (todo < 0) msg_panic("smtp_fputs: negative todo %ld", (long) todo); /* * Do the I/O, protected against timeout. */ smtp_timeout_reset(stream); err = (vstream_fwrite(stream, cp, todo) != todo || vstream_fputs("\r\n", stream) == VSTREAM_EOF); smtp_timeout_detect(stream); /* * See if there was a problem. */ if (err != 0) { if (msg_verbose) msg_info("smtp_fputs: EOF"); vstream_longjmp(stream, SMTP_ERR_EOF); } } /* smtp_fwrite - write one string to SMTP peer */ void smtp_fwrite(const char *cp, ssize_t todo, VSTREAM *stream) { ssize_t err; if (todo < 0) msg_panic("smtp_fwrite: negative todo %ld", (long) todo); /* * Do the I/O, protected against timeout. */ smtp_timeout_reset(stream); err = (vstream_fwrite(stream, cp, todo) != todo); smtp_timeout_detect(stream); /* * See if there was a problem. */ if (err != 0) { if (msg_verbose) msg_info("smtp_fwrite: EOF"); vstream_longjmp(stream, SMTP_ERR_EOF); } } /* smtp_fputc - write to SMTP peer */ void smtp_fputc(int ch, VSTREAM *stream) { int stat; /* * Do the I/O, protected against timeout. */ smtp_timeout_reset(stream); stat = VSTREAM_PUTC(ch, stream); smtp_timeout_detect(stream); /* * See if there was a problem. */ if (stat == VSTREAM_EOF) { if (msg_verbose) msg_info("smtp_fputc: EOF"); vstream_longjmp(stream, SMTP_ERR_EOF); } }