From 2c7cac91ed6e7db0f6937923d2b57f97dbdbc337 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 28 Apr 2024 11:53:30 +0200 Subject: Adding upstream version 8.4.4. Signed-off-by: Daniel Baumann --- lib/buffer.c | 498 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 498 insertions(+) create mode 100644 lib/buffer.c (limited to 'lib/buffer.c') diff --git a/lib/buffer.c b/lib/buffer.c new file mode 100644 index 0000000..e976fec --- /dev/null +++ b/lib/buffer.c @@ -0,0 +1,498 @@ +/* + * 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 this program; see the file COPYING; if not, write to the Free Software + * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA + */ + +#include + +#include "memory.h" +#include "buffer.h" +#include "log.h" +#include "network.h" +#include "lib_errors.h" + +#include + +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 , 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; +} -- cgit v1.2.3