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-rw-r--r--lib/buffer.c483
1 files changed, 483 insertions, 0 deletions
diff --git a/lib/buffer.c b/lib/buffer.c
new file mode 100644
index 0000000..63df56a
--- /dev/null
+++ b/lib/buffer.c
@@ -0,0 +1,483 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Buffering of output and input.
+ * Copyright (C) 1998 Kunihiro Ishiguro
+ */
+
+#include <zebra.h>
+
+#include "memory.h"
+#include "buffer.h"
+#include "log.h"
+#include "network.h"
+#include "lib_errors.h"
+
+#include <stddef.h>
+
+DEFINE_MTYPE_STATIC(LIB, BUFFER, "Buffer");
+DEFINE_MTYPE_STATIC(LIB, BUFFER_DATA, "Buffer data");
+
+/* 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[]; /* 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 boundary. */
+#define BUFFER_SIZE_DEFAULT 4096
+
+#define BUFFER_DATA_FREE(D) XFREE(MTYPE_BUFFER_DATA, (D))
+
+/* Make new buffer. */
+struct buffer *buffer_new(size_t size)
+{
+ struct buffer *b;
+
+ b = XCALLOC(MTYPE_BUFFER, 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);
+ XFREE(MTYPE_BUFFER, 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 = XMALLOC(MTYPE_TMP, 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;
+}
+
+/* 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 = XMALLOC(MTYPE_BUFFER_DATA,
+ offsetof(struct buffer_data, data) + b->size);
+ 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, uint8_t 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));
+}
+
+/* Expand \n to \r\n */
+void buffer_put_crlf(struct buffer *b, const void *origp, size_t origsize)
+{
+ struct buffer_data *data = b->tail;
+ const char *p = origp, *end = p + origsize, *lf;
+ size_t size;
+
+ lf = memchr(p, '\n', end - p);
+
+ /* We use even last one byte of data buffer. */
+ while (p < end) {
+ size_t avail, chunk;
+
+ /* If there is no data buffer add it. */
+ if (data == NULL || data->cp == b->size)
+ data = buffer_add(b);
+
+ size = (lf ? lf : end) - p;
+ avail = b->size - data->cp;
+
+ chunk = (size <= avail) ? size : avail;
+ memcpy(data->data + data->cp, p, chunk);
+
+ p += chunk;
+ data->cp += chunk;
+
+ if (lf && size <= avail) {
+ /* we just copied up to (including) a '\n' */
+ if (data->cp == b->size)
+ data = buffer_add(b);
+ data->data[data->cp++] = '\r';
+ if (data->cp == b->size)
+ data = buffer_add(b);
+ data->data[data->cp++] = '\n';
+
+ p++;
+ lf = memchr(p, '\n', end - p);
+ }
+ }
+}
+
+/* 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;
+}
+
+/* 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)
+ height = 1;
+ else if (height >= 2)
+ height--;
+ if (width < 1)
+ width = 1;
+
+ /* For erase and more data add two to b's buffer_data count.*/
+ if (b->head->next == NULL) {
+ iov_alloc = array_size(small_iov);
+ 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) {
+ iov = XREALLOC(MTYPE_TMP, iov,
+ iov_alloc * sizeof(*iov));
+ } else {
+ /* This should absolutely never occur. */
+ flog_err_sys(
+ EC_LIB_SYSTEM_CALL,
+ "%s: corruption detected: iov_small overflowed; head %p, tail %p, head->next %p",
+ __func__, (void *)b->head,
+ (void *)b->tail, (void *)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);
+ nbytes = writev(fd, c_iov, iov_size);
+ if (nbytes < 0) {
+ flog_err(EC_LIB_SOCKET,
+ "%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 */
+ nbytes = writev(fd, iov, iov_index);
+ if (nbytes < 0)
+ flog_err(EC_LIB_SOCKET, "%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);
+}
+
+/* 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;
+
+ if (fd < 0)
+ return BUFFER_ERROR;
+
+ 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;
+ flog_err(EC_LIB_SOCKET, "%s: write error on fd %d: %s",
+ __func__, fd, safe_strerror(errno));
+ return BUFFER_ERROR;
+ }
+
+ /* Free printed buffer data. */
+ while (written > 0) {
+ if (!(d = b->head)) {
+ flog_err(
+ EC_LIB_DEVELOPMENT,
+ "%s: corruption detected: buffer queue empty, but written is %lu",
+ __func__, (unsigned long)written);
+ 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 (b->head)
+ /* Buffer is not empty, so do not attempt to write the new data.
+ */
+ nbytes = 0;
+ else {
+ nbytes = write(fd, p, size);
+ if (nbytes < 0) {
+ if (ERRNO_IO_RETRY(errno))
+ nbytes = 0;
+ else {
+ flog_err(EC_LIB_SOCKET,
+ "%s: write error on fd %d: %s",
+ __func__, fd, safe_strerror(errno));
+ 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;
+}
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