/*++ /* NAME /* vstream 3 /* SUMMARY /* light-weight buffered I/O package /* SYNOPSIS /* #include /* /* VSTREAM *vstream_fopen(path, flags, mode) /* char *path; /* int flags; /* int mode; /* /* VSTREAM *vstream_fdopen(fd, flags) /* int fd; /* int flags; /* /* int vstream_fclose(stream) /* VSTREAM *stream; /* /* VSTREAM *vstream_printf(format, ...) /* char *format; /* /* VSTREAM *vstream_fprintf(stream, format, ...) /* VSTREAM *stream; /* char *format; /* /* int VSTREAM_GETC(stream) /* VSTREAM *stream; /* /* int VSTREAM_PUTC(ch, stream) /* int ch; /* /* int VSTREAM_GETCHAR(void) /* /* int VSTREAM_PUTCHAR(ch) /* int ch; /* /* int vstream_ungetc(stream, ch) /* VSTREAM *stream; /* int ch; /* /* int vstream_fputs(str, stream) /* char *str; /* VSTREAM *stream; /* /* long vstream_ftell(stream) /* VSTREAM *stream; /* /* long vstream_fseek(stream, offset, whence) /* VSTREAM *stream; /* long offset; /* int whence; /* /* int vstream_fflush(stream) /* VSTREAM *stream; /* /* int vstream_fread(stream, buf, len) /* VSTREAM *stream; /* char *buf; /* int len; /* /* int vstream_fwrite(stream, buf, len) /* VSTREAM *stream; /* char *buf; /* int len; /* /* void vstream_control(stream, name, ...) /* VSTREAM *stream; /* int name; /* /* int vstream_fileno(stream) /* VSTREAM *stream; /* /* int vstream_ferror(stream) /* VSTREAM *stream; /* /* int vstream_feof(stream) /* VSTREAM *stream; /* /* int vstream_clearerr(stream) /* VSTREAM *stream; /* /* char *VSTREAM_PATH(stream) /* VSTREAM *stream; /* /* char *vstream_vfprintf(vp, format, ap) /* char *format; /* va_list *ap; /* /* int vstream_peek(stream) /* VSTREAM *stream; /* DESCRIPTION /* The \fIvstream\fR module implements light-weight buffered I/O /* similar to the standard I/O routines. /* /* The interface is implemented in terms of VSTREAM structure /* pointers, also called streams. For convenience, three streams /* are predefined: VSTREAM_IN, VSTREAM_OUT, and VSTREAM_ERR. These /* streams are connected to the standard input, output and error /* file descriptors, respectively. /* /* Although the interface is patterned after the standard I/O /* library, there are some major differences: /* .IP \(bu /* File descriptors are not limited to the range 0..255. This /* was reason #1 to write these routines in the first place. /* .IP \(bu /* The application can switch between reading and writing on /* the same stream without having to perform a flush or seek /* operation, and can change write position without having to /* flush. This was reason #2. Upon position or direction change, /* unread input is discarded, and unwritten output is flushed /* automatically. Exception: with double-buffered streams, unread /* input is not discarded upon change of I/O direction, and /* output flushing is delayed until the read buffer must be refilled. /* .IP \(bu /* A bidirectional stream can read and write with the same buffer /* and file descriptor, or it can have separate read/write /* buffers and/or file descriptors. /* .IP \(bu /* No automatic flushing of VSTREAM_OUT upon program exit, or of /* VSTREAM_ERR at any time. No unbuffered or line buffered modes. /* This functionality may be added when it is really needed. /* .PP /* vstream_fopen() opens the named file and associates a buffered /* stream with it. The \fIpath\fR, \fIflags\fR and \fImode\fR /* arguments are passed on to the open(2) routine. The result is /* a null pointer in case of problems. The \fIpath\fR argument is /* copied and can be looked up with VSTREAM_PATH(). /* /* vstream_fdopen() takes an open file and associates a buffered /* stream with it. The \fIflags\fR argument specifies how the file /* was opened. vstream_fdopen() either succeeds or never returns. /* /* vstream_fclose() closes the named buffered stream. The result /* is 0 in case of success, VSTREAM_EOF in case of problems. /* /* vstream_fprintf() formats its arguments according to the /* \fIformat\fR argument and writes the result to the named stream. /* The result is the stream argument. It understands the s, c, d, u, /* o, x, X, e, f and g format types, the l modifier, field width and /* precision, sign, and padding with zeros or spaces. In addition, /* vstream_fprintf() recognizes the %m format specifier and expands /* it to the error message corresponding to the current value of the /* global \fIerrno\fR variable. /* /* vstream_printf() performs formatted output to the standard output /* stream. /* /* VSTREAM_GETC() reads the next character from the named stream. /* The result is VSTREAM_EOF when end-of-file is reached or if a read /* error was detected. VSTREAM_GETC() is an unsafe macro that /* evaluates some arguments more than once. /* /* VSTREAM_GETCHAR() is an alias for VSTREAM_GETC(VSTREAM_IN). /* /* VSTREAM_PUTC() appends the specified character to the specified /* stream. The result is the stored character, or VSTREAM_EOF in /* case of problems. VSTREAM_PUTC() is an unsafe macro that /* evaluates some arguments more than once. /* /* VSTREAM_PUTCHAR(c) is an alias for VSTREAM_PUTC(c, VSTREAM_OUT). /* /* vstream_unget() pushes back a character onto the specified stream /* and returns the character, or VSTREAM_EOF in case of problems. /* It is an error to push back before reading (or immediately after /* changing the stream offset via vstream_fseek()). Upon successful /* return, vstream_unget() clears the end-of-file stream flag. /* /* vstream_fputs() appends the given null-terminated string to the /* specified buffered stream. The result is 0 in case of success, /* VSTREAM_EOF in case of problems. /* /* vstream_ftell() returns the file offset for the specified stream, /* -1 if the stream is connected to a non-seekable file. /* /* vstream_fseek() changes the file position for the next read or write /* operation. Unwritten output is flushed. With unidirectional streams, /* unread input is discarded. The \fIoffset\fR argument specifies the file /* position from the beginning of the file (\fIwhence\fR is SEEK_SET), /* from the current file position (\fIwhence\fR is SEEK_CUR), or from /* the file end (SEEK_END). The result value is the file offset /* from the beginning of the file, -1 in case of problems. /* /* vstream_fflush() flushes unwritten data to a file that was /* opened in read-write or write-only mode. /* vstream_fflush() returns 0 in case of success, VSTREAM_EOF in /* case of problems. It is an error to flush a read-only stream. /* /* vstream_fread() and vstream_fwrite() perform unformatted I/O /* on the named stream. The result value is the number of bytes /* transferred. A short count is returned in case of end-of-file /* or error conditions. /* /* vstream_control() allows the user to fine tune the behavior of /* the specified stream. The arguments are a list of (name, /* value) pairs, terminated with VSTREAM_CTL_END. /* The following lists the names and the types of the corresponding /* value arguments. /* .IP "VSTREAM_CTL_READ_FN (int (*)(int, void *, unsigned))" /* The argument specifies an alternative for the read(2) function, /* for example, a read function that enforces a time limit. /* .IP "VSTREAM_CTL_WRITE_FN (int (*)(int, void *, unsigned))" /* The argument specifies an alternative for the write(2) function, /* for example, a write function that enforces a time limit. /* .IP "VSTREAM_CTL_PATH (char *)" /* Updates the stored pathname of the specified stream. The pathname /* is copied. /* .IP "VSTREAM_CTL_DOUBLE (no value)" /* Use separate buffers for reading and for writing. This prevents /* unread input from being discarded upon change of I/O direction. /* .IP "VSTREAM_CTL_READ_FD (int) /* The argument specifies the file descriptor to be used for reading. /* This feature is limited to double-buffered streams, and makes the /* stream non-seekable. /* .IP "VSTREAM_CTL_WRITE_FD (int) /* The argument specifies the file descriptor to be used for writing. /* This feature is limited to double-buffered streams, and makes the /* stream non-seekable. /* .IP "VSTREAM_CTL_WAITPID_FN (int (*)(pid_t, WAIT_STATUS_T *, int))" /* A pointer to function that behaves like waitpid(). This information /* is used by the vstream_pclose() routine. /* .PP /* vstream_fileno() gives access to the file handle associated with /* a buffered stream. With streams that have separate read/write /* file descriptors, the result is the current descriptor. /* /* VSTREAM_PATH() is an unsafe macro that returns the name stored /* with vstream_fopen() or with vstream_control(). The macro is /* unsafe because it evaluates some arguments more than once. /* /* vstream_ferror() (vstream_feof()) returns non-zero when a previous /* operation on the specified stream caused an error (end-of-file) /* condition. /* /* vstream_clearerr() resets the error and end-of-file indication of /* specified stream, and returns no useful result. /* /* vstream_vfprintf() provides an alternate interface /* for formatting an argument list according to a format string. /* /* vstream_peek() returns the number of characters that can be /* read from the named stream without refilling the read buffer. /* DIAGNOSTICS /* Panics: interface violations. Fatal errors: out of memory. /* SEE ALSO /* vbuf_print(3) formatting engine /* BUGS /* Should use mmap() on reasonable systems. /* 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 #include /* 44BSD stdarg.h uses abort() */ #include #include #include #include #include #include /* Utility library. */ #include "mymalloc.h" #include "msg.h" #include "vbuf_print.h" #include "vstring.h" #include "vstream.h" /* Application-specific. */ /* * Forward declarations. */ static int vstream_buf_get_ready(VBUF *); static int vstream_buf_put_ready(VBUF *); static int vstream_buf_space(VBUF *, int); /* * Initialization of the three pre-defined streams. Pre-allocate a static * I/O buffer for the standard error stream, so that the error handler can * produce a diagnostic even when memory allocation fails. */ static unsigned char vstream_fstd_buf[VSTREAM_BUFSIZE]; VSTREAM vstream_fstd[] = { {{ 0, /* flags */ 0, 0, 0, 0, /* buffer */ vstream_buf_get_ready, vstream_buf_put_ready, vstream_buf_space, }, STDIN_FILENO, (VSTREAM_FN) read, (VSTREAM_FN) write,}, {{ 0, /* flags */ 0, 0, 0, 0, /* buffer */ vstream_buf_get_ready, vstream_buf_put_ready, vstream_buf_space, }, STDOUT_FILENO, (VSTREAM_FN) read, (VSTREAM_FN) write,}, {{ VBUF_FLAG_FIXED | VSTREAM_FLAG_WRITE, vstream_fstd_buf, VSTREAM_BUFSIZE, VSTREAM_BUFSIZE, vstream_fstd_buf, vstream_buf_get_ready, vstream_buf_put_ready, vstream_buf_space, }, STDERR_FILENO, (VSTREAM_FN) read, (VSTREAM_FN) write,}, }; #define VSTREAM_STATIC(v) ((v) >= VSTREAM_IN && (v) <= VSTREAM_ERR) /* * A bunch of macros to make some expressions more readable. XXX We're * assuming that O_RDONLY == 0, O_WRONLY == 1, O_RDWR == 2. */ #define VSTREAM_ACC_MASK(f) ((f) & (O_APPEND | O_WRONLY | O_RDWR)) #define VSTREAM_CAN_READ(f) (VSTREAM_ACC_MASK(f) == O_RDONLY \ || VSTREAM_ACC_MASK(f) == O_RDWR) #define VSTREAM_CAN_WRITE(f) (VSTREAM_ACC_MASK(f) & O_WRONLY \ || VSTREAM_ACC_MASK(f) & O_RDWR \ || VSTREAM_ACC_MASK(f) & O_APPEND) #define VSTREAM_BUF_COUNT(bp, n) \ ((bp)->flags & VSTREAM_FLAG_READ ? -(n) : (n)) #define VSTREAM_BUF_AT_START(bp) { \ (bp)->cnt = VSTREAM_BUF_COUNT((bp), (bp)->len); \ (bp)->ptr = (bp)->data; \ } #define VSTREAM_BUF_AT_OFFSET(bp, offset) { \ (bp)->ptr = (bp)->data + (offset); \ (bp)->cnt = VSTREAM_BUF_COUNT(bp, (bp)->len - (offset)); \ } #define VSTREAM_BUF_AT_END(bp) { \ (bp)->cnt = 0; \ (bp)->ptr = (bp)->data + (bp)->len; \ } #define VSTREAM_BUF_ZERO(bp) { \ (bp)->flags = 0; \ (bp)->data = (bp)->ptr = 0; \ (bp)->len = (bp)->cnt = 0; \ } #define VSTREAM_BUF_ACTIONS(bp, get_action, put_action, space_action) { \ (bp)->get_ready = (get_action); \ (bp)->put_ready = (put_action); \ (bp)->space = (space_action); \ } #define VSTREAM_SAVE_STATE(stream, buffer, filedes) { \ stream->buffer = stream->buf; \ stream->filedes = stream->fd; \ } #define VSTREAM_RESTORE_STATE(stream, buffer, filedes) do { \ stream->buffer.flags = stream->buf.flags; \ stream->buf = stream->buffer; \ stream->fd = stream->filedes; \ } while(0) #define VSTREAM_FORK_STATE(stream, buffer, filedes) { \ stream->buffer = stream->buf; \ stream->filedes = stream->fd; \ stream->buffer.data = stream->buffer.ptr = 0; \ stream->buffer.len = stream->buffer.cnt = 0; \ stream->buffer.flags &= ~VSTREAM_FLAG_FIXED; \ }; #define VSTREAM_FLAG_READ_DOUBLE (VSTREAM_FLAG_READ | VSTREAM_FLAG_DOUBLE) #define VSTREAM_FLAG_WRITE_DOUBLE (VSTREAM_FLAG_WRITE | VSTREAM_FLAG_DOUBLE) #define VSTREAM_FFLUSH_SOME(stream) \ vstream_fflush_some((stream), (stream)->buf.len - (stream)->buf.cnt) /* vstream_buf_init - initialize buffer */ static void vstream_buf_init(VBUF *bp, int flags) { /* * Initialize the buffer such that the first data access triggers a * buffer boundary action. */ VSTREAM_BUF_ZERO(bp); VSTREAM_BUF_ACTIONS(bp, VSTREAM_CAN_READ(flags) ? vstream_buf_get_ready : 0, VSTREAM_CAN_WRITE(flags) ? vstream_buf_put_ready : 0, vstream_buf_space); } /* vstream_buf_alloc - allocate buffer memory */ static void vstream_buf_alloc(VBUF *bp, int len) { int used = bp->ptr - bp->data; const char *myname = "vstream_buf_alloc"; if (len < bp->len) msg_panic("%s: attempt to shrink buffer", myname); if (bp->flags & VSTREAM_FLAG_FIXED) msg_panic("%s: unable to extend fixed-size buffer", myname); /* * Late buffer allocation allows the user to override the default policy. * If a buffer already exists, allow for the presence of (output) data. */ bp->data = (unsigned char *) (bp->data ? myrealloc((char *) bp->data, len) : mymalloc(len)); bp->len = len; if (bp->flags & VSTREAM_FLAG_READ) bp->ptr = bp->data + used; else VSTREAM_BUF_AT_OFFSET(bp, used); } /* vstream_buf_wipe - reset buffer to initial state */ static void vstream_buf_wipe(VBUF *bp) { if ((bp->flags & VBUF_FLAG_FIXED) == 0 && bp->data) myfree((char *) bp->data); VSTREAM_BUF_ZERO(bp); VSTREAM_BUF_ACTIONS(bp, 0, 0, 0); } /* vstream_fflush_some - flush some buffered data */ static int vstream_fflush_some(VSTREAM *stream, int to_flush) { const char *myname = "vstream_fflush_some"; VBUF *bp = &stream->buf; int used; int left_over; char *data; int len; int n; /* * Sanity checks. It is illegal to flush a read-only stream. Otherwise, * if there is buffered input, discard the input. If there is buffered * output, require that the amount to flush is larger than the amount to * keep, so that we can memcpy() the residue. */ if (bp->put_ready == 0) msg_panic("%s: read-only stream", myname); switch (bp->flags & (VSTREAM_FLAG_WRITE | VSTREAM_FLAG_READ)) { case VSTREAM_FLAG_READ: /* discard input */ VSTREAM_BUF_AT_END(bp); /* FALLTHROUGH */ case 0: /* flush after seek? */ return ((bp->flags & VSTREAM_FLAG_ERR) ? VSTREAM_EOF : 0); case VSTREAM_FLAG_WRITE: /* output buffered */ break; case VSTREAM_FLAG_WRITE | VSTREAM_FLAG_READ: msg_panic("%s: read/write stream", myname); } used = bp->len - bp->cnt; left_over = used - to_flush; if (msg_verbose > 2 && stream != VSTREAM_ERR) msg_info("%s: fd %d flush %d", myname, stream->fd, to_flush); if (to_flush < 0 || left_over < 0) msg_panic("%s: bad to_flush %d", myname, to_flush); if (to_flush < left_over) msg_panic("%s: to_flush < left_over", myname); if (to_flush == 0) return ((bp->flags & VSTREAM_FLAG_ERR) ? VSTREAM_EOF : 0); if (bp->flags & VSTREAM_FLAG_ERR) return (VSTREAM_EOF); /* * When flushing a buffer, allow for partial writes. These can happen * while talking to a network. Update the cached file seek position, if * any. */ for (data = (char *) bp->data, len = to_flush; len > 0; len -= n, data += n) { if ((n = stream->write_fn(stream->fd, data, len)) <= 0) { bp->flags |= VSTREAM_FLAG_ERR; return (VSTREAM_EOF); } if (msg_verbose > 2 && stream != VSTREAM_ERR && n != to_flush) msg_info("%s: %d flushed %d/%d", myname, stream->fd, n, to_flush); } if (bp->flags & VSTREAM_FLAG_SEEK) stream->offset += to_flush; /* * Allow for partial buffer flush requests. We use memcpy() for reasons * of portability to pre-ANSI environments (SunOS 4.x or Ultrix 4.x :-). * This is OK because we have already verified that the to_flush count is * larger than the left_over count. */ if (left_over > 0) memcpy(bp->data, bp->data + to_flush, left_over); bp->cnt += to_flush; bp->ptr -= to_flush; return ((bp->flags & VSTREAM_FLAG_ERR) ? VSTREAM_EOF : 0); } /* vstream_fflush_delayed - delayed stream flush for double-buffered stream */ static int vstream_fflush_delayed(VSTREAM *stream) { int status; /* * Sanity check. */ if ((stream->buf.flags & VSTREAM_FLAG_READ_DOUBLE) != VSTREAM_FLAG_READ_DOUBLE) msg_panic("vstream_fflush_delayed: bad flags"); /* * Temporarily swap buffers and flush unwritten data. This may seem like * a lot of work, but it's peanuts compared to the write(2) call that we * already have avoided. For example, delayed flush is never used on a * non-pipelined SMTP connection. */ stream->buf.flags &= ~VSTREAM_FLAG_READ; VSTREAM_SAVE_STATE(stream, read_buf, read_fd); stream->buf.flags |= VSTREAM_FLAG_WRITE; VSTREAM_RESTORE_STATE(stream, write_buf, write_fd); status = VSTREAM_FFLUSH_SOME(stream); stream->buf.flags &= ~VSTREAM_FLAG_WRITE; VSTREAM_SAVE_STATE(stream, write_buf, write_fd); stream->buf.flags |= VSTREAM_FLAG_READ; VSTREAM_RESTORE_STATE(stream, read_buf, read_fd); return (status); } /* vstream_buf_get_ready - vbuf callback to make buffer ready for reading */ static int vstream_buf_get_ready(VBUF *bp) { VSTREAM *stream = VBUF_TO_APPL(bp, VSTREAM, buf); const char *myname = "vstream_buf_get_ready"; int n; /* * Detect a change of I/O direction or position. If so, flush any * unwritten output immediately when the stream is single-buffered, or * when the stream is double-buffered and the read buffer is empty. */ switch (bp->flags & (VSTREAM_FLAG_WRITE | VSTREAM_FLAG_READ)) { case VSTREAM_FLAG_WRITE: /* change direction */ if (bp->ptr > bp->data) if ((bp->flags & VSTREAM_FLAG_DOUBLE) == 0 || stream->read_buf.cnt >= 0) if (VSTREAM_FFLUSH_SOME(stream)) return (VSTREAM_EOF); bp->flags &= ~VSTREAM_FLAG_WRITE; if (bp->flags & VSTREAM_FLAG_DOUBLE) VSTREAM_SAVE_STATE(stream, write_buf, write_fd); /* FALLTHROUGH */ case 0: /* change position */ bp->flags |= VSTREAM_FLAG_READ; if (bp->flags & VSTREAM_FLAG_DOUBLE) { VSTREAM_RESTORE_STATE(stream, read_buf, read_fd); if (bp->cnt < 0) return (0); } /* FALLTHROUGH */ case VSTREAM_FLAG_READ: /* no change */ break; case VSTREAM_FLAG_WRITE | VSTREAM_FLAG_READ: msg_panic("%s: read/write stream", myname); } /* * If this is the first GET operation, allocate a buffer. Late buffer * allocation gives the application a chance to override the default * buffering policy. */ if (bp->data == 0) vstream_buf_alloc(bp, VSTREAM_BUFSIZE); /* * If the stream is double-buffered and the write buffer is not empty, * this is the time to flush the write buffer. Delayed flushes reduce * system call overhead, and on TCP sockets, avoid triggering Nagle's * algorithm. */ if ((bp->flags & VSTREAM_FLAG_DOUBLE) && stream->write_buf.len > stream->write_buf.cnt) if (vstream_fflush_delayed(stream)) return (VSTREAM_EOF); /* * Did we receive an EOF indication? */ if (bp->flags & VSTREAM_FLAG_EOF) return (VSTREAM_EOF); /* * Fill the buffer with as much data as we can handle, or with as much * data as is available right now, whichever is less. Update the cached * file seek position, if any. */ switch (n = stream->read_fn(stream->fd, bp->data, bp->len)) { case -1: bp->flags |= VSTREAM_FLAG_ERR; return (VSTREAM_EOF); case 0: bp->flags |= VSTREAM_FLAG_EOF; return (VSTREAM_EOF); default: if (msg_verbose > 2) msg_info("%s: fd %d got %d", myname, stream->fd, n); bp->cnt = -n; bp->ptr = bp->data; if (bp->flags & VSTREAM_FLAG_SEEK) stream->offset += n; return (0); } } /* vstream_buf_put_ready - vbuf callback to make buffer ready for writing */ static int vstream_buf_put_ready(VBUF *bp) { VSTREAM *stream = VBUF_TO_APPL(bp, VSTREAM, buf); const char *myname = "vstream_buf_put_ready"; /* * Sanity checks. Detect a change of I/O direction or position. If so, * discard unread input, and reset the buffer to the beginning. */ switch (bp->flags & (VSTREAM_FLAG_WRITE | VSTREAM_FLAG_READ)) { case VSTREAM_FLAG_READ: /* change direction */ bp->flags &= ~VSTREAM_FLAG_READ; if (bp->flags & VSTREAM_FLAG_DOUBLE) VSTREAM_SAVE_STATE(stream, read_buf, read_fd); /* FALLTHROUGH */ case 0: /* change position */ bp->flags |= VSTREAM_FLAG_WRITE; if (bp->flags & VSTREAM_FLAG_DOUBLE) VSTREAM_RESTORE_STATE(stream, write_buf, write_fd); else VSTREAM_BUF_AT_START(bp); /* FALLTHROUGH */ case VSTREAM_FLAG_WRITE: /* no change */ break; case VSTREAM_FLAG_WRITE | VSTREAM_FLAG_READ: msg_panic("%s: read/write stream", myname); } /* * Remember the direction. If this is the first PUT operation for this * stream, allocate a new buffer; obviously there is no data to be * flushed yet. Otherwise, flush the buffer if it is full. */ if (bp->data == 0) { vstream_buf_alloc(bp, VSTREAM_BUFSIZE); } else if (bp->cnt <= 0) { if (VSTREAM_FFLUSH_SOME(stream)) return (VSTREAM_EOF); } return (0); } /* vstream_buf_space - reserve space ahead of time */ static int vstream_buf_space(VBUF *bp, int want) { VSTREAM *stream = VBUF_TO_APPL(bp, VSTREAM, buf); int used; int incr; int shortage; const char *myname = "vstream_buf_space"; /* * Sanity checks. Reserving space implies writing. It is illegal to write * to a read-only stream. Detect a change of I/O direction or position. * If so, reset the buffer to the beginning. */ if (bp->put_ready == 0) msg_panic("%s: read-only stream", myname); switch (bp->flags & (VSTREAM_FLAG_READ | VSTREAM_FLAG_WRITE)) { case VSTREAM_FLAG_READ: /* change direction */ bp->flags &= ~VSTREAM_FLAG_READ; if (bp->flags & VSTREAM_FLAG_DOUBLE) VSTREAM_SAVE_STATE(stream, read_buf, read_fd); /* FALLTHROUGH */ case 0: /* change position */ bp->flags |= VSTREAM_FLAG_WRITE; if (bp->flags & VSTREAM_FLAG_DOUBLE) VSTREAM_RESTORE_STATE(stream, write_buf, write_fd); else VSTREAM_BUF_AT_START(bp); /* FALLTHROUGH */ case VSTREAM_FLAG_WRITE: /* no change */ break; case VSTREAM_FLAG_READ | VSTREAM_FLAG_WRITE: msg_panic("%s: read/write stream", myname); } /* * See if enough space is available. If not, flush a multiple of * VSTREAM_BUFSIZE bytes and resize the buffer to a multiple of * VSTREAM_BUFSIZE. We flush multiples of VSTREAM_BUFSIZE in an attempt * to keep file updates block-aligned for better performance. */ #define VSTREAM_TRUNCATE(count, base) (((count) / (base)) * (base)) #define VSTREAM_ROUNDUP(count, base) VSTREAM_TRUNCATE(count + base - 1, base) if (want > bp->cnt) { if ((used = bp->len - bp->cnt) > VSTREAM_BUFSIZE) if (vstream_fflush_some(stream, VSTREAM_TRUNCATE(used, VSTREAM_BUFSIZE))) return (VSTREAM_EOF); if ((shortage = (want - bp->cnt)) > 0) { incr = VSTREAM_ROUNDUP(shortage, VSTREAM_BUFSIZE); vstream_buf_alloc(bp, bp->len + incr); } } return (vstream_ferror(stream) ? VSTREAM_EOF : 0); /* mmap() may fail */ } /* vstream_fseek - change I/O position */ long vstream_fseek(VSTREAM *stream, long offset, int whence) { const char *myname = "vstream_fseek"; VBUF *bp = &stream->buf; /* * Flush any unwritten output. Discard any unread input. Position the * buffer at the end, so that the next GET or PUT operation triggers a * buffer boundary action. */ switch (bp->flags & (VSTREAM_FLAG_READ | VSTREAM_FLAG_WRITE)) { case VSTREAM_FLAG_WRITE: if (bp->ptr > bp->data) if (VSTREAM_FFLUSH_SOME(stream)) return (-1); /* FALLTHROUGH */ case VSTREAM_FLAG_READ: case 0: VSTREAM_BUF_AT_END(bp); break; case VSTREAM_FLAG_READ | VSTREAM_FLAG_WRITE: msg_panic("%s: read/write stream", myname); } /* * Clear the read/write flags to inform the buffer boundary action * routines that we may have changed I/O position. */ bp->flags &= ~(VSTREAM_FLAG_READ | VSTREAM_FLAG_WRITE); /* * Shave an unnecessary system call. */ if (bp->flags & VSTREAM_FLAG_NSEEK) { errno = ESPIPE; return (-1); } /* * Update the cached file seek position. */ if ((stream->offset = lseek(stream->fd, offset, whence)) < 0) { bp->flags |= VSTREAM_FLAG_NSEEK; } else { bp->flags |= VSTREAM_FLAG_SEEK; } bp->flags &= ~VSTREAM_FLAG_EOF; return (stream->offset); } /* vstream_ftell - return file offset */ long vstream_ftell(VSTREAM *stream) { VBUF *bp = &stream->buf; /* * Shave an unnecessary syscall. */ if (bp->flags & VSTREAM_FLAG_NSEEK) { errno = ESPIPE; return (-1); } /* * Use the cached file offset when available. This is the offset after * the last read, write or seek operation. */ if ((bp->flags & VSTREAM_FLAG_SEEK) == 0) { if ((stream->offset = lseek(stream->fd, 0L, SEEK_CUR)) < 0) { bp->flags |= VSTREAM_FLAG_NSEEK; return (-1); } bp->flags |= VSTREAM_FLAG_SEEK; } /* * If this is a read buffer, subtract the number of unread bytes from the * cached offset. Remember that read counts are negative. */ if (bp->flags & VSTREAM_FLAG_READ) return (stream->offset + bp->cnt); /* * If this is a write buffer, add the number of unwritten bytes to the * cached offset. */ if (bp->flags & VSTREAM_FLAG_WRITE) return (stream->offset + (bp->ptr - bp->data)); /* * Apparently, this is a new buffer, or a buffer after seek, so there is * no need to account for unread or unwritten data. */ return (stream->offset); } /* vstream_fdopen - add buffering to pre-opened stream */ VSTREAM *vstream_fdopen(int fd, int flags) { VSTREAM *stream; /* * Sanity check. */ if (fd < 0) msg_panic("vstream_fdopen: bad file %d", fd); /* * Initialize buffers etc. but do as little as possible. Late buffer * allocation etc. gives the application a chance to override default * policies. Either this, or the vstream*open() routines would have to * have a really ugly interface with lots of mostly-unused arguments (can * you say VMS?). */ stream = (VSTREAM *) mymalloc(sizeof(*stream)); stream->fd = fd; stream->read_fn = VSTREAM_CAN_READ(flags) ? (VSTREAM_FN) read : 0; stream->write_fn = VSTREAM_CAN_WRITE(flags) ? (VSTREAM_FN) write : 0; vstream_buf_init(&stream->buf, flags); stream->offset = 0; stream->path = 0; stream->pid = 0; stream->waitpid_fn = 0; return (stream); } /* vstream_fopen - open buffered file stream */ VSTREAM *vstream_fopen(const char *path, int flags, int mode) { VSTREAM *stream; int fd; if ((fd = open(path, flags, mode)) < 0) { return (0); } else { stream = vstream_fdopen(fd, flags); stream->path = mystrdup(path); return (stream); } } /* vstream_fflush - flush write buffer */ int vstream_fflush(VSTREAM *stream) { if ((stream->buf.flags & VSTREAM_FLAG_READ_DOUBLE) == VSTREAM_FLAG_READ_DOUBLE && stream->write_buf.len > stream->write_buf.cnt) vstream_fflush_delayed(stream); return (VSTREAM_FFLUSH_SOME(stream)); } /* vstream_fclose - close buffered stream */ int vstream_fclose(VSTREAM *stream) { int err; if (stream->pid != 0) msg_panic("vstream_fclose: stream has process"); if ((stream->buf.flags & VSTREAM_FLAG_WRITE_DOUBLE) != 0) vstream_fflush(stream); err = vstream_ferror(stream); if (stream->buf.flags & VSTREAM_FLAG_DOUBLE) { err |= close(stream->read_fd); if (stream->write_fd != stream->read_fd) err |= close(stream->write_fd); vstream_buf_wipe(&stream->read_buf); vstream_buf_wipe(&stream->write_buf); stream->buf = stream->read_buf; } else { err |= close(stream->fd); vstream_buf_wipe(&stream->buf); } if (stream->path) myfree(stream->path); if (!VSTREAM_STATIC(stream)) myfree((char *) stream); return (err ? VSTREAM_EOF : 0); } /* vstream_printf - formatted print to stdout */ VSTREAM *vstream_printf(const char *fmt,...) { VSTREAM *stream = VSTREAM_OUT; va_list ap; va_start(ap, fmt); vbuf_print(&stream->buf, fmt, ap); va_end(ap); return (stream); } /* vstream_fprintf - formatted print to buffered stream */ VSTREAM *vstream_fprintf(VSTREAM *stream, const char *fmt,...) { va_list ap; va_start(ap, fmt); vbuf_print(&stream->buf, fmt, ap); va_end(ap); return (stream); } /* vstream_fputs - write string to stream */ int vstream_fputs(const char *str, VSTREAM *stream) { int ch; while ((ch = *str++) != 0) if (VSTREAM_PUTC(ch, stream) == VSTREAM_EOF) return (VSTREAM_EOF); return (0); } /* vstream_control - fine control */ void vstream_control(VSTREAM *stream, int name,...) { const char *myname = "vstream_control"; va_list ap; for (va_start(ap, name); name != VSTREAM_CTL_END; name = va_arg(ap, int)) { switch (name) { case VSTREAM_CTL_READ_FN: stream->read_fn = va_arg(ap, VSTREAM_FN); break; case VSTREAM_CTL_WRITE_FN: stream->write_fn = va_arg(ap, VSTREAM_FN); break; case VSTREAM_CTL_PATH: if (stream->path) myfree(stream->path); stream->path = mystrdup(va_arg(ap, char *)); break; case VSTREAM_CTL_DOUBLE: if ((stream->buf.flags & VSTREAM_FLAG_DOUBLE) == 0) { stream->buf.flags |= VSTREAM_FLAG_DOUBLE; if (stream->buf.flags & VSTREAM_FLAG_READ) { VSTREAM_SAVE_STATE(stream, read_buf, read_fd); VSTREAM_FORK_STATE(stream, write_buf, write_fd); } else { VSTREAM_SAVE_STATE(stream, write_buf, write_fd); VSTREAM_FORK_STATE(stream, read_buf, read_fd); } } break; case VSTREAM_CTL_READ_FD: if ((stream->buf.flags & VSTREAM_FLAG_DOUBLE) == 0) msg_panic("VSTREAM_CTL_READ_FD requires double buffering"); stream->read_fd = va_arg(ap, int); stream->buf.flags |= VSTREAM_FLAG_NSEEK; break; case VSTREAM_CTL_WRITE_FD: if ((stream->buf.flags & VSTREAM_FLAG_DOUBLE) == 0) msg_panic("VSTREAM_CTL_WRITE_FD requires double buffering"); stream->write_fd = va_arg(ap, int); stream->buf.flags |= VSTREAM_FLAG_NSEEK; break; case VSTREAM_CTL_WAITPID_FN: stream->waitpid_fn = va_arg(ap, VSTREAM_WAITPID_FN); break; default: msg_panic("%s: bad name %d", myname, name); } } } /* vstream_vfprintf - formatted print engine */ VSTREAM *vstream_vfprintf(VSTREAM *vp, const char *format, va_list ap) { vbuf_print(&vp->buf, format, ap); return (vp); } /* vstream_peek - peek at a stream */ int vstream_peek(VSTREAM *vp) { if (vp->buf.flags & VSTREAM_FLAG_READ) { return (-vp->buf.cnt); } else if (vp->buf.flags & VSTREAM_FLAG_DOUBLE) { return (-vp->read_buf.cnt); } else { return (0); } }