From 7c1e52ba6f3994dc127118f491258ce84d0beb52 Mon Sep 17 00:00:00 2001 From: "Dr. David Alan Gilbert" Date: Thu, 21 May 2015 13:24:15 +0100 Subject: Move copy out of qemu_peek_buffer qemu_peek_buffer currently copies the data it reads into a buffer, however a future patch wants access to the buffer without the copy, hence rework to remove the copy to the layer above. Signed-off-by: Dr. David Alan Gilbert Reviewed-by: Amit Shah Reviewed-by: Juan Quintela Signed-off-by: Juan Quintela --- include/migration/qemu-file.h | 2 +- migration/qemu-file.c | 12 +++++++----- migration/vmstate.c | 5 +++-- 3 files changed, 11 insertions(+), 8 deletions(-) diff --git a/include/migration/qemu-file.h b/include/migration/qemu-file.h index 318aa1e..4f67d79 100644 --- a/include/migration/qemu-file.h +++ b/include/migration/qemu-file.h @@ -157,7 +157,7 @@ static inline void qemu_put_ubyte(QEMUFile *f, unsigned int v) void qemu_put_be16(QEMUFile *f, unsigned int v); void qemu_put_be32(QEMUFile *f, unsigned int v); void qemu_put_be64(QEMUFile *f, uint64_t v); -int qemu_peek_buffer(QEMUFile *f, uint8_t *buf, int size, size_t offset); +int qemu_peek_buffer(QEMUFile *f, uint8_t **buf, int size, size_t offset); int qemu_get_buffer(QEMUFile *f, uint8_t *buf, int size); ssize_t qemu_put_compression_data(QEMUFile *f, const uint8_t *p, size_t size, int level); diff --git a/migration/qemu-file.c b/migration/qemu-file.c index 0ef543a..965a757 100644 --- a/migration/qemu-file.c +++ b/migration/qemu-file.c @@ -349,14 +349,14 @@ void qemu_file_skip(QEMUFile *f, int size) } /* - * Read 'size' bytes from file (at 'offset') into buf without moving the - * pointer. + * Read 'size' bytes from file (at 'offset') without moving the + * pointer and set 'buf' to point to that data. * * 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 qemu_peek_buffer(QEMUFile *f, uint8_t **buf, int size, size_t offset) { int pending; int index; @@ -392,7 +392,7 @@ int qemu_peek_buffer(QEMUFile *f, uint8_t *buf, int size, size_t offset) size = pending; } - memcpy(buf, f->buf + index, size); + *buf = f->buf + index; return size; } @@ -411,11 +411,13 @@ int qemu_get_buffer(QEMUFile *f, uint8_t *buf, int size) while (pending > 0) { int res; + uint8_t *src; - res = qemu_peek_buffer(f, buf, MIN(pending, IO_BUF_SIZE), 0); + res = qemu_peek_buffer(f, &src, MIN(pending, IO_BUF_SIZE), 0); if (res == 0) { return done; } + memcpy(buf, src, res); qemu_file_skip(f, res); buf += res; pending -= res; diff --git a/migration/vmstate.c b/migration/vmstate.c index 108995e..6138d1a 100644 --- a/migration/vmstate.c +++ b/migration/vmstate.c @@ -358,7 +358,7 @@ static int vmstate_subsection_load(QEMUFile *f, const VMStateDescription *vmsd, trace_vmstate_subsection_load(vmsd->name); while (qemu_peek_byte(f, 0) == QEMU_VM_SUBSECTION) { - char idstr[256]; + char idstr[256], *idstr_ret; int ret; uint8_t version_id, len, size; const VMStateDescription *sub_vmsd; @@ -369,11 +369,12 @@ static int vmstate_subsection_load(QEMUFile *f, const VMStateDescription *vmsd, trace_vmstate_subsection_load_bad(vmsd->name, "(short)"); return 0; } - size = qemu_peek_buffer(f, (uint8_t *)idstr, len, 2); + size = qemu_peek_buffer(f, (uint8_t **)&idstr_ret, len, 2); if (size != len) { trace_vmstate_subsection_load_bad(vmsd->name, "(peek fail)"); return 0; } + memcpy(idstr, idstr_ret, size); idstr[size] = 0; if (strncmp(vmsd->name, idstr, strlen(vmsd->name)) != 0) { -- cgit v1.1