+/*
+ * QEMU System Emulator
+ *
+ * Copyright (c) 2003-2008 Fabrice Bellard
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
#include "qemu-common.h"
#include "qemu/iov.h"
#include "qemu/sockets.h"
#include "block/coroutine.h"
#include "migration/migration.h"
#include "migration/qemu-file.h"
+#include "trace.h"
#define IO_BUF_SIZE 32768
#define MAX_IOV_SIZE MIN(IOV_MAX, 64)
int last_error;
};
-typedef struct QEMUFileStdio {
- FILE *stdio_file;
- QEMUFile *file;
-} QEMUFileStdio;
-
-typedef struct QEMUFileSocket {
- int fd;
- QEMUFile *file;
-} QEMUFileSocket;
-
-static ssize_t socket_writev_buffer(void *opaque, struct iovec *iov, int iovcnt,
- int64_t pos)
-{
- QEMUFileSocket *s = opaque;
- ssize_t len;
- ssize_t size = iov_size(iov, iovcnt);
-
- len = iov_send(s->fd, iov, iovcnt, 0, size);
- if (len < size) {
- len = -socket_error();
- }
- return len;
-}
-
-static int socket_get_fd(void *opaque)
-{
- QEMUFileSocket *s = opaque;
-
- return s->fd;
-}
-
-static int socket_get_buffer(void *opaque, uint8_t *buf, int64_t pos, int size)
-{
- QEMUFileSocket *s = opaque;
- ssize_t len;
-
- for (;;) {
- len = qemu_recv(s->fd, buf, size, 0);
- if (len != -1) {
- break;
- }
- if (socket_error() == EAGAIN) {
- yield_until_fd_readable(s->fd);
- } else if (socket_error() != EINTR) {
- break;
- }
- }
-
- if (len == -1) {
- len = -socket_error();
- }
- return len;
-}
-
-static int socket_close(void *opaque)
-{
- QEMUFileSocket *s = opaque;
- closesocket(s->fd);
- g_free(s);
- return 0;
-}
-
-static int stdio_get_fd(void *opaque)
-{
- QEMUFileStdio *s = opaque;
-
- return fileno(s->stdio_file);
-}
-
-static int stdio_put_buffer(void *opaque, const uint8_t *buf, int64_t pos,
- int size)
-{
- QEMUFileStdio *s = opaque;
- return fwrite(buf, 1, size, s->stdio_file);
-}
-
-static int stdio_get_buffer(void *opaque, uint8_t *buf, int64_t pos, int size)
-{
- QEMUFileStdio *s = opaque;
- FILE *fp = s->stdio_file;
- int bytes;
-
- for (;;) {
- clearerr(fp);
- bytes = fread(buf, 1, size, fp);
- if (bytes != 0 || !ferror(fp)) {
- break;
- }
- if (errno == EAGAIN) {
- yield_until_fd_readable(fileno(fp));
- } else if (errno != EINTR) {
- break;
- }
- }
- return bytes;
-}
-
-static int stdio_pclose(void *opaque)
-{
- QEMUFileStdio *s = opaque;
- int ret;
- ret = pclose(s->stdio_file);
- if (ret == -1) {
- ret = -errno;
- } else if (!WIFEXITED(ret) || WEXITSTATUS(ret) != 0) {
- /* close succeeded, but non-zero exit code: */
- ret = -EIO; /* fake errno value */
- }
- g_free(s);
- return ret;
-}
-
-static int stdio_fclose(void *opaque)
-{
- QEMUFileStdio *s = opaque;
- int ret = 0;
-
- if (s->file->ops->put_buffer || s->file->ops->writev_buffer) {
- int fd = fileno(s->stdio_file);
- struct stat st;
-
- ret = fstat(fd, &st);
- if (ret == 0 && S_ISREG(st.st_mode)) {
- /*
- * If the file handle is a regular file make sure the
- * data is flushed to disk before signaling success.
- */
- ret = fsync(fd);
- if (ret != 0) {
- ret = -errno;
- return ret;
- }
- }
- }
- if (fclose(s->stdio_file) == EOF) {
- ret = -errno;
- }
- g_free(s);
- return ret;
-}
-
-static const QEMUFileOps stdio_pipe_read_ops = {
- .get_fd = stdio_get_fd,
- .get_buffer = stdio_get_buffer,
- .close = stdio_pclose
-};
-
-static const QEMUFileOps stdio_pipe_write_ops = {
- .get_fd = stdio_get_fd,
- .put_buffer = stdio_put_buffer,
- .close = stdio_pclose
-};
-
-QEMUFile *qemu_popen_cmd(const char *command, const char *mode)
-{
- FILE *stdio_file;
- QEMUFileStdio *s;
-
- if (mode == NULL || (mode[0] != 'r' && mode[0] != 'w') || mode[1] != 0) {
- fprintf(stderr, "qemu_popen: Argument validity check failed\n");
- return NULL;
- }
-
- stdio_file = popen(command, mode);
- if (stdio_file == NULL) {
- return NULL;
- }
-
- s = g_malloc0(sizeof(QEMUFileStdio));
-
- s->stdio_file = stdio_file;
-
- if (mode[0] == 'r') {
- s->file = qemu_fopen_ops(s, &stdio_pipe_read_ops);
- } else {
- s->file = qemu_fopen_ops(s, &stdio_pipe_write_ops);
- }
- return s->file;
-}
-
-static const QEMUFileOps stdio_file_read_ops = {
- .get_fd = stdio_get_fd,
- .get_buffer = stdio_get_buffer,
- .close = stdio_fclose
-};
-
-static const QEMUFileOps stdio_file_write_ops = {
- .get_fd = stdio_get_fd,
- .put_buffer = stdio_put_buffer,
- .close = stdio_fclose
-};
-
-static ssize_t unix_writev_buffer(void *opaque, struct iovec *iov, int iovcnt,
- int64_t pos)
-{
- QEMUFileSocket *s = opaque;
- ssize_t len, offset;
- ssize_t size = iov_size(iov, iovcnt);
- ssize_t total = 0;
-
- assert(iovcnt > 0);
- offset = 0;
- while (size > 0) {
- /* Find the next start position; skip all full-sized vector elements */
- while (offset >= iov[0].iov_len) {
- offset -= iov[0].iov_len;
- iov++, iovcnt--;
- }
-
- /* skip `offset' bytes from the (now) first element, undo it on exit */
- assert(iovcnt > 0);
- iov[0].iov_base += offset;
- iov[0].iov_len -= offset;
-
- do {
- len = writev(s->fd, iov, iovcnt);
- } while (len == -1 && errno == EINTR);
- if (len == -1) {
- return -errno;
- }
-
- /* Undo the changes above */
- iov[0].iov_base -= offset;
- iov[0].iov_len += offset;
-
- /* Prepare for the next iteration */
- offset += len;
- total += len;
- size -= len;
- }
-
- return total;
-}
-
-static int unix_get_buffer(void *opaque, uint8_t *buf, int64_t pos, int size)
-{
- QEMUFileSocket *s = opaque;
- ssize_t len;
-
- for (;;) {
- len = read(s->fd, buf, size);
- if (len != -1) {
- break;
- }
- if (errno == EAGAIN) {
- yield_until_fd_readable(s->fd);
- } else if (errno != EINTR) {
- break;
- }
- }
-
- if (len == -1) {
- len = -errno;
- }
- return len;
-}
-
-static int unix_close(void *opaque)
-{
- QEMUFileSocket *s = opaque;
- close(s->fd);
- g_free(s);
- return 0;
-}
-
-static const QEMUFileOps unix_read_ops = {
- .get_fd = socket_get_fd,
- .get_buffer = unix_get_buffer,
- .close = unix_close
-};
-
-static const QEMUFileOps unix_write_ops = {
- .get_fd = socket_get_fd,
- .writev_buffer = unix_writev_buffer,
- .close = unix_close
-};
-
-QEMUFile *qemu_fdopen(int fd, const char *mode)
-{
- QEMUFileSocket *s;
-
- if (mode == NULL ||
- (mode[0] != 'r' && mode[0] != 'w') ||
- mode[1] != 'b' || mode[2] != 0) {
- fprintf(stderr, "qemu_fdopen: Argument validity check failed\n");
- return NULL;
- }
-
- s = g_malloc0(sizeof(QEMUFileSocket));
- s->fd = fd;
-
- if (mode[0] == 'r') {
- s->file = qemu_fopen_ops(s, &unix_read_ops);
- } else {
- s->file = qemu_fopen_ops(s, &unix_write_ops);
- }
- return s->file;
-}
-
-static const QEMUFileOps socket_read_ops = {
- .get_fd = socket_get_fd,
- .get_buffer = socket_get_buffer,
- .close = socket_close
-};
-
-static const QEMUFileOps socket_write_ops = {
- .get_fd = socket_get_fd,
- .writev_buffer = socket_writev_buffer,
- .close = socket_close
-};
-
bool qemu_file_mode_is_not_valid(const char *mode)
{
if (mode == NULL ||
return false;
}
-QEMUFile *qemu_fopen_socket(int fd, const char *mode)
-{
- QEMUFileSocket *s;
-
- if (qemu_file_mode_is_not_valid(mode)) {
- return NULL;
- }
-
- s = g_malloc0(sizeof(QEMUFileSocket));
- s->fd = fd;
- if (mode[0] == 'w') {
- qemu_set_block(s->fd);
- s->file = qemu_fopen_ops(s, &socket_write_ops);
- } else {
- s->file = qemu_fopen_ops(s, &socket_read_ops);
- }
- return s->file;
-}
-
-QEMUFile *qemu_fopen(const char *filename, const char *mode)
-{
- QEMUFileStdio *s;
-
- if (qemu_file_mode_is_not_valid(mode)) {
- return NULL;
- }
-
- s = g_malloc0(sizeof(QEMUFileStdio));
-
- s->stdio_file = fopen(filename, mode);
- if (!s->stdio_file) {
- goto fail;
- }
-
- if (mode[0] == 'w') {
- s->file = qemu_fopen_ops(s, &stdio_file_write_ops);
- } else {
- s->file = qemu_fopen_ops(s, &stdio_file_read_ops);
- }
- return s->file;
-fail:
- g_free(s);
- return NULL;
-}
-
QEMUFile *qemu_fopen_ops(void *opaque, const QEMUFileOps *ops)
{
QEMUFile *f;
}
}
-static inline bool qemu_file_is_writable(QEMUFile *f)
+bool qemu_file_is_writable(QEMUFile *f)
{
return f->ops->writev_buffer || f->ops->put_buffer;
}
return RAM_SAVE_CONTROL_NOT_SUPP;
}
-static void qemu_fill_buffer(QEMUFile *f)
+/*
+ * Attempt to fill the buffer from the underlying file
+ * Returns the number of bytes read, or negative value for an error.
+ *
+ * Note that it can return a partially full buffer even in a not error/not EOF
+ * case if the underlying file descriptor gives a short read, and that can
+ * happen even on a blocking fd.
+ */
+static ssize_t qemu_fill_buffer(QEMUFile *f)
{
int len;
int pending;
} else if (len != -EAGAIN) {
qemu_file_set_error(f, len);
}
+
+ return len;
}
int qemu_get_fd(QEMUFile *f)
ret = f->last_error;
}
g_free(f);
+ trace_qemu_file_fclose();
return ret;
}
}
}
+/*
+ * Read 'size' bytes from file (at 'offset') into buf without moving the
+ * pointer.
+ *
+ * It will return size bytes unless there was an error, in which case it will
+ * return as many as it managed to read (assuming blocking fd's which
+ * all current QEMUFile are)
+ */
int qemu_peek_buffer(QEMUFile *f, uint8_t *buf, int size, size_t offset)
{
int pending;
int index;
assert(!qemu_file_is_writable(f));
+ assert(offset < IO_BUF_SIZE);
+ assert(size <= IO_BUF_SIZE - offset);
+ /* The 1st byte to read from */
index = f->buf_index + offset;
+ /* The number of available bytes starting at index */
pending = f->buf_size - index;
- if (pending < size) {
- qemu_fill_buffer(f);
+
+ /*
+ * qemu_fill_buffer might return just a few bytes, even when there isn't
+ * an error, so loop collecting them until we get enough.
+ */
+ while (pending < size) {
+ int received = qemu_fill_buffer(f);
+
+ if (received <= 0) {
+ break;
+ }
+
index = f->buf_index + offset;
pending = f->buf_size - index;
}
return size;
}
+/*
+ * Read 'size' bytes of data from the file into buf.
+ * 'size' can be larger than the internal buffer.
+ *
+ * It will return size bytes unless there was an error, in which case it will
+ * return as many as it managed to read (assuming blocking fd's which
+ * all current QEMUFile are)
+ */
int qemu_get_buffer(QEMUFile *f, uint8_t *buf, int size)
{
int pending = size;
while (pending > 0) {
int res;
- res = qemu_peek_buffer(f, buf, pending, 0);
+ res = qemu_peek_buffer(f, buf, MIN(pending, IO_BUF_SIZE), 0);
if (res == 0) {
return done;
}
return done;
}
+/*
+ * Peeks a single byte from the buffer; this isn't guaranteed to work if
+ * offset leaves a gap after the previous read/peeked data.
+ */
int qemu_peek_byte(QEMUFile *f, int offset)
{
int index = f->buf_index + offset;
assert(!qemu_file_is_writable(f));
+ assert(offset < IO_BUF_SIZE);
if (index >= f->buf_size) {
qemu_fill_buffer(f);
v |= qemu_get_be32(f);
return v;
}
+
+#define QSB_CHUNK_SIZE (1 << 10)
+#define QSB_MAX_CHUNK_SIZE (16 * QSB_CHUNK_SIZE)
+
+/**
+ * Create a QEMUSizedBuffer
+ * This type of buffer uses scatter-gather lists internally and
+ * can grow to any size. Any data array in the scatter-gather list
+ * can hold different amount of bytes.
+ *
+ * @buffer: Optional buffer to copy into the QSB
+ * @len: size of initial buffer; if @buffer is given, buffer must
+ * hold at least len bytes
+ *
+ * Returns a pointer to a QEMUSizedBuffer or NULL on allocation failure
+ */
+QEMUSizedBuffer *qsb_create(const uint8_t *buffer, size_t len)
+{
+ QEMUSizedBuffer *qsb;
+ size_t alloc_len, num_chunks, i, to_copy;
+ size_t chunk_size = (len > QSB_MAX_CHUNK_SIZE)
+ ? QSB_MAX_CHUNK_SIZE
+ : QSB_CHUNK_SIZE;
+
+ num_chunks = DIV_ROUND_UP(len ? len : QSB_CHUNK_SIZE, chunk_size);
+ alloc_len = num_chunks * chunk_size;
+
+ qsb = g_try_new0(QEMUSizedBuffer, 1);
+ if (!qsb) {
+ return NULL;
+ }
+
+ qsb->iov = g_try_new0(struct iovec, num_chunks);
+ if (!qsb->iov) {
+ g_free(qsb);
+ return NULL;
+ }
+
+ qsb->n_iov = num_chunks;
+
+ for (i = 0; i < num_chunks; i++) {
+ qsb->iov[i].iov_base = g_try_malloc0(chunk_size);
+ if (!qsb->iov[i].iov_base) {
+ /* qsb_free is safe since g_free can cope with NULL */
+ qsb_free(qsb);
+ return NULL;
+ }
+
+ qsb->iov[i].iov_len = chunk_size;
+ if (buffer) {
+ to_copy = (len - qsb->used) > chunk_size
+ ? chunk_size : (len - qsb->used);
+ memcpy(qsb->iov[i].iov_base, &buffer[qsb->used], to_copy);
+ qsb->used += to_copy;
+ }
+ }
+
+ qsb->size = alloc_len;
+
+ return qsb;
+}
+
+/**
+ * Free the QEMUSizedBuffer
+ *
+ * @qsb: The QEMUSizedBuffer to free
+ */
+void qsb_free(QEMUSizedBuffer *qsb)
+{
+ size_t i;
+
+ if (!qsb) {
+ return;
+ }
+
+ for (i = 0; i < qsb->n_iov; i++) {
+ g_free(qsb->iov[i].iov_base);
+ }
+ g_free(qsb->iov);
+ g_free(qsb);
+}
+
+/**
+ * Get the number of used bytes in the QEMUSizedBuffer
+ *
+ * @qsb: A QEMUSizedBuffer
+ *
+ * Returns the number of bytes currently used in this buffer
+ */
+size_t qsb_get_length(const QEMUSizedBuffer *qsb)
+{
+ return qsb->used;
+}
+
+/**
+ * Set the length of the buffer; the primary usage of this
+ * function is to truncate the number of used bytes in the buffer.
+ * The size will not be extended beyond the current number of
+ * allocated bytes in the QEMUSizedBuffer.
+ *
+ * @qsb: A QEMUSizedBuffer
+ * @new_len: The new length of bytes in the buffer
+ *
+ * Returns the number of bytes the buffer was truncated or extended
+ * to.
+ */
+size_t qsb_set_length(QEMUSizedBuffer *qsb, size_t new_len)
+{
+ if (new_len <= qsb->size) {
+ qsb->used = new_len;
+ } else {
+ qsb->used = qsb->size;
+ }
+ return qsb->used;
+}
+
+/**
+ * Get the iovec that holds the data for a given position @pos.
+ *
+ * @qsb: A QEMUSizedBuffer
+ * @pos: The index of a byte in the buffer
+ * @d_off: Pointer to an offset that this function will indicate
+ * at what position within the returned iovec the byte
+ * is to be found
+ *
+ * Returns the index of the iovec that holds the byte at the given
+ * index @pos in the byte stream; a negative number if the iovec
+ * for the given position @pos does not exist.
+ */
+static ssize_t qsb_get_iovec(const QEMUSizedBuffer *qsb,
+ off_t pos, off_t *d_off)
+{
+ ssize_t i;
+ off_t curr = 0;
+
+ if (pos > qsb->used) {
+ return -1;
+ }
+
+ for (i = 0; i < qsb->n_iov; i++) {
+ if (curr + qsb->iov[i].iov_len > pos) {
+ *d_off = pos - curr;
+ return i;
+ }
+ curr += qsb->iov[i].iov_len;
+ }
+ return -1;
+}
+
+/*
+ * Convert the QEMUSizedBuffer into a flat buffer.
+ *
+ * Note: If at all possible, try to avoid this function since it
+ * may unnecessarily copy memory around.
+ *
+ * @qsb: pointer to QEMUSizedBuffer
+ * @start: offset to start at
+ * @count: number of bytes to copy
+ * @buf: a pointer to a buffer to write into (at least @count bytes)
+ *
+ * Returns the number of bytes copied into the output buffer
+ */
+ssize_t qsb_get_buffer(const QEMUSizedBuffer *qsb, off_t start,
+ size_t count, uint8_t *buffer)
+{
+ const struct iovec *iov;
+ size_t to_copy, all_copy;
+ ssize_t index;
+ off_t s_off;
+ off_t d_off = 0;
+ char *s;
+
+ if (start > qsb->used) {
+ return 0;
+ }
+
+ all_copy = qsb->used - start;
+ if (all_copy > count) {
+ all_copy = count;
+ } else {
+ count = all_copy;
+ }
+
+ index = qsb_get_iovec(qsb, start, &s_off);
+ if (index < 0) {
+ return 0;
+ }
+
+ while (all_copy > 0) {
+ iov = &qsb->iov[index];
+
+ s = iov->iov_base;
+
+ to_copy = iov->iov_len - s_off;
+ if (to_copy > all_copy) {
+ to_copy = all_copy;
+ }
+ memcpy(&buffer[d_off], &s[s_off], to_copy);
+
+ d_off += to_copy;
+ all_copy -= to_copy;
+
+ s_off = 0;
+ index++;
+ }
+
+ return count;
+}
+
+/**
+ * Grow the QEMUSizedBuffer to the given size and allocate
+ * memory for it.
+ *
+ * @qsb: A QEMUSizedBuffer
+ * @new_size: The new size of the buffer
+ *
+ * Return:
+ * a negative error code in case of memory allocation failure
+ * or
+ * the new size of the buffer. The returned size may be greater or equal
+ * to @new_size.
+ */
+static ssize_t qsb_grow(QEMUSizedBuffer *qsb, size_t new_size)
+{
+ size_t needed_chunks, i;
+
+ if (qsb->size < new_size) {
+ struct iovec *new_iov;
+ size_t size_diff = new_size - qsb->size;
+ size_t chunk_size = (size_diff > QSB_MAX_CHUNK_SIZE)
+ ? QSB_MAX_CHUNK_SIZE : QSB_CHUNK_SIZE;
+
+ needed_chunks = DIV_ROUND_UP(size_diff, chunk_size);
+
+ new_iov = g_try_new(struct iovec, qsb->n_iov + needed_chunks);
+ if (new_iov == NULL) {
+ return -ENOMEM;
+ }
+
+ /* Allocate new chunks as needed into new_iov */
+ for (i = qsb->n_iov; i < qsb->n_iov + needed_chunks; i++) {
+ new_iov[i].iov_base = g_try_malloc0(chunk_size);
+ new_iov[i].iov_len = chunk_size;
+ if (!new_iov[i].iov_base) {
+ size_t j;
+
+ /* Free previously allocated new chunks */
+ for (j = qsb->n_iov; j < i; j++) {
+ g_free(new_iov[j].iov_base);
+ }
+ g_free(new_iov);
+
+ return -ENOMEM;
+ }
+ }
+
+ /*
+ * Now we can't get any allocation errors, copy over to new iov
+ * and switch.
+ */
+ for (i = 0; i < qsb->n_iov; i++) {
+ new_iov[i] = qsb->iov[i];
+ }
+
+ qsb->n_iov += needed_chunks;
+ g_free(qsb->iov);
+ qsb->iov = new_iov;
+ qsb->size += (needed_chunks * chunk_size);
+ }
+
+ return qsb->size;
+}
+
+/**
+ * Write into the QEMUSizedBuffer at a given position and a given
+ * number of bytes. This function will automatically grow the
+ * QEMUSizedBuffer.
+ *
+ * @qsb: A QEMUSizedBuffer
+ * @source: A byte array to copy data from
+ * @pos: The position within the @qsb to write data to
+ * @size: The number of bytes to copy into the @qsb
+ *
+ * Returns @size or a negative error code in case of memory allocation failure,
+ * or with an invalid 'pos'
+ */
+ssize_t qsb_write_at(QEMUSizedBuffer *qsb, const uint8_t *source,
+ off_t pos, size_t count)
+{
+ ssize_t rc = qsb_grow(qsb, pos + count);
+ size_t to_copy;
+ size_t all_copy = count;
+ const struct iovec *iov;
+ ssize_t index;
+ char *dest;
+ off_t d_off, s_off = 0;
+
+ if (rc < 0) {
+ return rc;
+ }
+
+ if (pos + count > qsb->used) {
+ qsb->used = pos + count;
+ }
+
+ index = qsb_get_iovec(qsb, pos, &d_off);
+ if (index < 0) {
+ return -EINVAL;
+ }
+
+ while (all_copy > 0) {
+ iov = &qsb->iov[index];
+
+ dest = iov->iov_base;
+
+ to_copy = iov->iov_len - d_off;
+ if (to_copy > all_copy) {
+ to_copy = all_copy;
+ }
+
+ memcpy(&dest[d_off], &source[s_off], to_copy);
+
+ s_off += to_copy;
+ all_copy -= to_copy;
+
+ d_off = 0;
+ index++;
+ }
+
+ return count;
+}
+
+/**
+ * Create a deep copy of the given QEMUSizedBuffer.
+ *
+ * @qsb: A QEMUSizedBuffer
+ *
+ * Returns a clone of @qsb or NULL on allocation failure
+ */
+QEMUSizedBuffer *qsb_clone(const QEMUSizedBuffer *qsb)
+{
+ QEMUSizedBuffer *out = qsb_create(NULL, qsb_get_length(qsb));
+ size_t i;
+ ssize_t res;
+ off_t pos = 0;
+
+ if (!out) {
+ return NULL;
+ }
+
+ for (i = 0; i < qsb->n_iov; i++) {
+ res = qsb_write_at(out, qsb->iov[i].iov_base,
+ pos, qsb->iov[i].iov_len);
+ if (res < 0) {
+ qsb_free(out);
+ return NULL;
+ }
+ pos += res;
+ }
+
+ return out;
+}
+
+typedef struct QEMUBuffer {
+ QEMUSizedBuffer *qsb;
+ QEMUFile *file;
+} QEMUBuffer;
+
+static int buf_get_buffer(void *opaque, uint8_t *buf, int64_t pos, int size)
+{
+ QEMUBuffer *s = opaque;
+ ssize_t len = qsb_get_length(s->qsb) - pos;
+
+ if (len <= 0) {
+ return 0;
+ }
+
+ if (len > size) {
+ len = size;
+ }
+ return qsb_get_buffer(s->qsb, pos, len, buf);
+}
+
+static int buf_put_buffer(void *opaque, const uint8_t *buf,
+ int64_t pos, int size)
+{
+ QEMUBuffer *s = opaque;
+
+ return qsb_write_at(s->qsb, buf, pos, size);
+}
+
+static int buf_close(void *opaque)
+{
+ QEMUBuffer *s = opaque;
+
+ qsb_free(s->qsb);
+
+ g_free(s);
+
+ return 0;
+}
+
+const QEMUSizedBuffer *qemu_buf_get(QEMUFile *f)
+{
+ QEMUBuffer *p;
+
+ qemu_fflush(f);
+
+ p = f->opaque;
+
+ return p->qsb;
+}
+
+static const QEMUFileOps buf_read_ops = {
+ .get_buffer = buf_get_buffer,
+ .close = buf_close,
+};
+
+static const QEMUFileOps buf_write_ops = {
+ .put_buffer = buf_put_buffer,
+ .close = buf_close,
+};
+
+QEMUFile *qemu_bufopen(const char *mode, QEMUSizedBuffer *input)
+{
+ QEMUBuffer *s;
+
+ if (mode == NULL || (mode[0] != 'r' && mode[0] != 'w') ||
+ mode[1] != '\0') {
+ error_report("qemu_bufopen: Argument validity check failed");
+ return NULL;
+ }
+
+ s = g_malloc0(sizeof(QEMUBuffer));
+ if (mode[0] == 'r') {
+ s->qsb = input;
+ }
+
+ if (s->qsb == NULL) {
+ s->qsb = qsb_create(NULL, 0);
+ }
+ if (!s->qsb) {
+ g_free(s);
+ error_report("qemu_bufopen: qsb_create failed");
+ return NULL;
+ }
+
+
+ if (mode[0] == 'r') {
+ s->file = qemu_fopen_ops(s, &buf_read_ops);
+ } else {
+ s->file = qemu_fopen_ops(s, &buf_write_ops);
+ }
+ return s->file;
+}
projects / qemu.git / blobdiff