summaryrefslogtreecommitdiff
path: root/host/zebvty/buffer.c
diff options
context:
space:
mode:
Diffstat (limited to 'host/zebvty/buffer.c')
-rw-r--r--host/zebvty/buffer.c460
1 files changed, 460 insertions, 0 deletions
diff --git a/host/zebvty/buffer.c b/host/zebvty/buffer.c
new file mode 100644
index 0000000..0610ebb
--- /dev/null
+++ b/host/zebvty/buffer.c
@@ -0,0 +1,460 @@
+/*
+ * Buffering of output and input.
+ * Copyright (C) 1998 Kunihiro Ishiguro
+ *
+ * This file is part of GNU Zebra.
+ *
+ * GNU Zebra is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published
+ * by the Free Software Foundation; either version 2, or (at your
+ * option) any later version.
+ *
+ * GNU Zebra is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with GNU Zebra; see the file COPYING. If not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <errno.h>
+#include <stddef.h>
+#include <sys/uio.h>
+
+#include "buffer.h"
+#include "vty.h"
+
+/* Buffer master. */
+struct buffer {
+ /* Data list. */
+ struct buffer_data *head;
+ struct buffer_data *tail;
+
+ /* Size of each buffer_data chunk. */
+ size_t size;
+};
+
+/* Data container. */
+struct buffer_data {
+ struct buffer_data *next;
+
+ /* Location to add new data. */
+ size_t cp;
+
+ /* Pointer to data not yet flushed. */
+ size_t sp;
+
+ /* Actual data stream (variable length). */
+ unsigned char data[0]; /* real dimension is buffer->size */
+};
+
+/* It should always be true that: 0 <= sp <= cp <= size */
+
+/* Default buffer size (used if none specified). It is rounded up to the
+ next page boundery. */
+#define BUFFER_SIZE_DEFAULT 4096
+
+#define BUFFER_DATA_FREE(D) free((D))
+
+/* Make new buffer. */
+struct buffer *buffer_new(size_t size)
+{
+ struct buffer *b;
+
+ b = calloc(1, sizeof(struct buffer));
+
+ if (size)
+ b->size = size;
+ else {
+ static size_t default_size;
+ if (!default_size) {
+ long pgsz = sysconf(_SC_PAGESIZE);
+ default_size =
+ ((((BUFFER_SIZE_DEFAULT - 1) / pgsz) + 1) * pgsz);
+ }
+ b->size = default_size;
+ }
+
+ return b;
+}
+
+/* Free buffer. */
+void buffer_free(struct buffer *b)
+{
+ buffer_reset(b);
+ free(b);
+}
+
+/* Make string clone. */
+char *buffer_getstr(struct buffer *b)
+{
+ size_t totlen = 0;
+ struct buffer_data *data;
+ char *s;
+ char *p;
+
+ for (data = b->head; data; data = data->next)
+ totlen += data->cp - data->sp;
+ if (!(s = malloc(totlen + 1)))
+ return NULL;
+ p = s;
+ for (data = b->head; data; data = data->next) {
+ memcpy(p, data->data + data->sp, data->cp - data->sp);
+ p += data->cp - data->sp;
+ }
+ *p = '\0';
+ return s;
+}
+
+/* Return 1 if buffer is empty. */
+int buffer_empty(struct buffer *b)
+{
+ return (b->head == NULL);
+}
+
+/* Clear and free all allocated data. */
+void buffer_reset(struct buffer *b)
+{
+ struct buffer_data *data;
+ struct buffer_data *next;
+
+ for (data = b->head; data; data = next) {
+ next = data->next;
+ BUFFER_DATA_FREE(data);
+ }
+ b->head = b->tail = NULL;
+}
+
+/* Add buffer_data to the end of buffer. */
+static struct buffer_data *buffer_add(struct buffer *b)
+{
+ struct buffer_data *d;
+
+ d = malloc(offsetof(struct buffer_data, data[b->size]));
+ if (!d)
+ return NULL;
+ d->cp = d->sp = 0;
+ d->next = NULL;
+
+ if (b->tail)
+ b->tail->next = d;
+ else
+ b->head = d;
+ b->tail = d;
+
+ return d;
+}
+
+/* Write data to buffer. */
+void buffer_put(struct buffer *b, const void *p, size_t size)
+{
+ struct buffer_data *data = b->tail;
+ const char *ptr = p;
+
+ /* We use even last one byte of data buffer. */
+ while (size) {
+ size_t chunk;
+
+ /* If there is no data buffer add it. */
+ if (data == NULL || data->cp == b->size)
+ data = buffer_add(b);
+
+ chunk =
+ ((size <=
+ (b->size - data->cp)) ? size : (b->size - data->cp));
+ memcpy((data->data + data->cp), ptr, chunk);
+ size -= chunk;
+ ptr += chunk;
+ data->cp += chunk;
+ }
+}
+
+/* Insert character into the buffer. */
+void buffer_putc(struct buffer *b, u_char c)
+{
+ buffer_put(b, &c, 1);
+}
+
+/* Put string to the buffer. */
+void buffer_putstr(struct buffer *b, const char *c)
+{
+ buffer_put(b, c, strlen(c));
+}
+
+/* Keep flushing data to the fd until the buffer is empty or an error is
+ encountered or the operation would block. */
+buffer_status_t buffer_flush_all(struct buffer *b, int fd)
+{
+ buffer_status_t ret;
+ struct buffer_data *head;
+ size_t head_sp;
+
+ if (!b->head)
+ return BUFFER_EMPTY;
+ head_sp = (head = b->head)->sp;
+ /* Flush all data. */
+ while ((ret = buffer_flush_available(b, fd)) == BUFFER_PENDING) {
+ if ((b->head == head) && (head_sp == head->sp)
+ && (errno != EINTR))
+ /* No data was flushed, so kernel buffer must be full. */
+ return ret;
+ head_sp = (head = b->head)->sp;
+ }
+
+ return ret;
+}
+
+#if 0
+/* Flush enough data to fill a terminal window of the given scene (used only
+ by vty telnet interface). */
+buffer_status_t
+buffer_flush_window(struct buffer * b, int fd, int width, int height,
+ int erase_flag, int no_more_flag)
+{
+ int nbytes;
+ int iov_alloc;
+ int iov_index;
+ struct iovec *iov;
+ struct iovec small_iov[3];
+ char more[] = " --More-- ";
+ char erase[] =
+ { 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08,
+ ' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ',
+ 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08
+ };
+ struct buffer_data *data;
+ int column;
+
+ if (!b->head)
+ return BUFFER_EMPTY;
+
+ if (height < 1) {
+ zlog_warn
+ ("%s called with non-positive window height %d, forcing to 1",
+ __func__, height);
+ height = 1;
+ } else if (height >= 2)
+ height--;
+ if (width < 1) {
+ zlog_warn
+ ("%s called with non-positive window width %d, forcing to 1",
+ __func__, width);
+ width = 1;
+ }
+
+ /* For erase and more data add two to b's buffer_data count. */
+ if (b->head->next == NULL) {
+ iov_alloc = sizeof(small_iov) / sizeof(small_iov[0]);
+ iov = small_iov;
+ } else {
+ iov_alloc = ((height * (width + 2)) / b->size) + 10;
+ iov = XMALLOC(MTYPE_TMP, iov_alloc * sizeof(*iov));
+ }
+ iov_index = 0;
+
+ /* Previously print out is performed. */
+ if (erase_flag) {
+ iov[iov_index].iov_base = erase;
+ iov[iov_index].iov_len = sizeof erase;
+ iov_index++;
+ }
+
+ /* Output data. */
+ column = 1; /* Column position of next character displayed. */
+ for (data = b->head; data && (height > 0); data = data->next) {
+ size_t cp;
+
+ cp = data->sp;
+ while ((cp < data->cp) && (height > 0)) {
+ /* Calculate lines remaining and column position after displaying
+ this character. */
+ if (data->data[cp] == '\r')
+ column = 1;
+ else if ((data->data[cp] == '\n') || (column == width)) {
+ column = 1;
+ height--;
+ } else
+ column++;
+ cp++;
+ }
+ iov[iov_index].iov_base = (char *)(data->data + data->sp);
+ iov[iov_index++].iov_len = cp - data->sp;
+ data->sp = cp;
+
+ if (iov_index == iov_alloc)
+ /* This should not ordinarily happen. */
+ {
+ iov_alloc *= 2;
+ if (iov != small_iov) {
+ zlog_warn("%s: growing iov array to %d; "
+ "width %d, height %d, size %lu",
+ __func__, iov_alloc, width, height,
+ (u_long) b->size);
+ iov =
+ XREALLOC(MTYPE_TMP, iov,
+ iov_alloc * sizeof(*iov));
+ } else {
+ /* This should absolutely never occur. */
+ zlog_err
+ ("%s: corruption detected: iov_small overflowed; "
+ "head %p, tail %p, head->next %p",
+ __func__, b->head, b->tail, b->head->next);
+ iov =
+ XMALLOC(MTYPE_TMP,
+ iov_alloc * sizeof(*iov));
+ memcpy(iov, small_iov, sizeof(small_iov));
+ }
+ }
+ }
+
+ /* In case of `more' display need. */
+ if (b->tail && (b->tail->sp < b->tail->cp) && !no_more_flag) {
+ iov[iov_index].iov_base = more;
+ iov[iov_index].iov_len = sizeof more;
+ iov_index++;
+ }
+#ifdef IOV_MAX
+ /* IOV_MAX are normally defined in <sys/uio.h> , Posix.1g.
+ example: Solaris2.6 are defined IOV_MAX size at 16. */
+ {
+ struct iovec *c_iov = iov;
+ nbytes = 0; /* Make sure it's initialized. */
+
+ while (iov_index > 0) {
+ int iov_size;
+
+ iov_size =
+ ((iov_index > IOV_MAX) ? IOV_MAX : iov_index);
+ if ((nbytes = writev(fd, c_iov, iov_size)) < 0) {
+ zlog_warn("%s: writev to fd %d failed: %s",
+ __func__, fd, safe_strerror(errno));
+ break;
+ }
+
+ /* move pointer io-vector */
+ c_iov += iov_size;
+ iov_index -= iov_size;
+ }
+ }
+#else /* IOV_MAX */
+ if ((nbytes = writev(fd, iov, iov_index)) < 0)
+ zlog_warn("%s: writev to fd %d failed: %s",
+ __func__, fd, safe_strerror(errno));
+#endif /* IOV_MAX */
+
+ /* Free printed buffer data. */
+ while (b->head && (b->head->sp == b->head->cp)) {
+ struct buffer_data *del;
+ if (!(b->head = (del = b->head)->next))
+ b->tail = NULL;
+ BUFFER_DATA_FREE(del);
+ }
+
+ if (iov != small_iov)
+ XFREE(MTYPE_TMP, iov);
+
+ return (nbytes < 0) ? BUFFER_ERROR :
+ (b->head ? BUFFER_PENDING : BUFFER_EMPTY);
+}
+#endif
+
+/* This function (unlike other buffer_flush* functions above) is designed
+to work with non-blocking sockets. It does not attempt to write out
+all of the queued data, just a "big" chunk. It returns 0 if it was
+able to empty out the buffers completely, 1 if more flushing is
+required later, or -1 on a fatal write error. */
+buffer_status_t buffer_flush_available(struct buffer * b, int fd)
+{
+
+/* These are just reasonable values to make sure a significant amount of
+data is written. There's no need to go crazy and try to write it all
+in one shot. */
+#ifdef IOV_MAX
+#define MAX_CHUNKS ((IOV_MAX >= 16) ? 16 : IOV_MAX)
+#else
+#define MAX_CHUNKS 16
+#endif
+#define MAX_FLUSH 131072
+
+ struct buffer_data *d;
+ size_t written;
+ struct iovec iov[MAX_CHUNKS];
+ size_t iovcnt = 0;
+ size_t nbyte = 0;
+
+ for (d = b->head; d && (iovcnt < MAX_CHUNKS) && (nbyte < MAX_FLUSH);
+ d = d->next, iovcnt++) {
+ iov[iovcnt].iov_base = d->data + d->sp;
+ nbyte += (iov[iovcnt].iov_len = d->cp - d->sp);
+ }
+
+ if (!nbyte)
+ /* No data to flush: should we issue a warning message? */
+ return BUFFER_EMPTY;
+
+ /* only place where written should be sign compared */
+ if ((ssize_t) (written = writev(fd, iov, iovcnt)) < 0) {
+ if (ERRNO_IO_RETRY(errno))
+ /* Calling code should try again later. */
+ return BUFFER_PENDING;
+ return BUFFER_ERROR;
+ }
+
+ /* Free printed buffer data. */
+ while (written > 0) {
+ struct buffer_data *d;
+ if (!(d = b->head))
+ break;
+ if (written < d->cp - d->sp) {
+ d->sp += written;
+ return BUFFER_PENDING;
+ }
+
+ written -= (d->cp - d->sp);
+ if (!(b->head = d->next))
+ b->tail = NULL;
+ BUFFER_DATA_FREE(d);
+ }
+
+ return b->head ? BUFFER_PENDING : BUFFER_EMPTY;
+
+#undef MAX_CHUNKS
+#undef MAX_FLUSH
+}
+
+buffer_status_t
+buffer_write(struct buffer * b, int fd, const void *p, size_t size)
+{
+ ssize_t nbytes;
+
+#if 0
+ /* Should we attempt to drain any previously buffered data? This could help reduce latency in pushing out the data if we are stuck in a long-running thread that is preventing the main select loop from calling the flush thread... */
+
+ if (b->head && (buffer_flush_available(b, fd) == BUFFER_ERROR))
+ return BUFFER_ERROR;
+#endif
+ if (b->head)
+ /* Buffer is not empty, so do not attempt to write the new data. */
+ nbytes = 0;
+ else if ((nbytes = write(fd, p, size)) < 0) {
+ if (ERRNO_IO_RETRY(errno))
+ nbytes = 0;
+ else
+ return BUFFER_ERROR;
+ }
+ /* Add any remaining data to the buffer. */
+ {
+ size_t written = nbytes;
+ if (written < size)
+ buffer_put(b, ((const char *)p) + written,
+ size - written);
+ }
+ return b->head ? BUFFER_PENDING : BUFFER_EMPTY;
+}
personal git repositories of Harald Welte. Your mileage may vary