/* * QEMU buffered QEMUFile * * Copyright IBM, Corp. 2008 * * Authors: * Anthony Liguori <aliguori@us.ibm.com> * * This work is licensed under the terms of the GNU GPL, version 2. See * the COPYING file in the top-level directory. * */ #include "qemu-common.h" #include "hw/hw.h" #include "qemu-timer.h" #include "sysemu.h" #include "qemu-char.h" #include "buffered_file.h" //#define DEBUG_BUFFERED_FILE typedef struct QEMUFileBuffered { BufferedPutFunc *put_buffer; BufferedPutReadyFunc *put_ready; BufferedWaitForUnfreezeFunc *wait_for_unfreeze; BufferedCloseFunc *close; void *opaque; QEMUFile *file; int has_error; int freeze_output; size_t bytes_xfer; size_t xfer_limit; uint8_t *buffer; size_t buffer_size; size_t buffer_capacity; QEMUTimer *timer; } QEMUFileBuffered; #ifdef DEBUG_BUFFERED_FILE #define DPRINTF(fmt, ...) \ do { printf("buffered-file: " fmt, ## __VA_ARGS__); } while (0) #else #define DPRINTF(fmt, ...) \ do { } while (0) #endif static void buffered_append(QEMUFileBuffered *s, const uint8_t *buf, size_t size) { if (size > (s->buffer_capacity - s->buffer_size)) { void *tmp; DPRINTF("increasing buffer capacity from %zu by %zu\n", s->buffer_capacity, size + 1024); s->buffer_capacity += size + 1024; tmp = qemu_realloc(s->buffer, s->buffer_capacity); if (tmp == NULL) { fprintf(stderr, "qemu file buffer expansion failed\n"); exit(1); } s->buffer = tmp; } memcpy(s->buffer + s->buffer_size, buf, size); s->buffer_size += size; } static void buffered_flush(QEMUFileBuffered *s) { size_t offset = 0; if (s->has_error) { DPRINTF("flush when error, bailing\n"); return; } DPRINTF("flushing %zu byte(s) of data\n", s->buffer_size); while (offset < s->buffer_size) { ssize_t ret; ret = s->put_buffer(s->opaque, s->buffer + offset, s->buffer_size - offset); if (ret == -EAGAIN) { DPRINTF("backend not ready, freezing\n"); s->freeze_output = 1; break; } if (ret <= 0) { DPRINTF("error flushing data, %zd\n", ret); s->has_error = 1; break; } else { DPRINTF("flushed %zd byte(s)\n", ret); offset += ret; } } DPRINTF("flushed %zu of %zu byte(s)\n", offset, s->buffer_size); memmove(s->buffer, s->buffer + offset, s->buffer_size - offset); s->buffer_size -= offset; } static int buffered_put_buffer(void *opaque, const uint8_t *buf, int64_t pos, int size) { QEMUFileBuffered *s = opaque; int offset = 0; ssize_t ret; DPRINTF("putting %d bytes at %" PRId64 "\n", size, pos); if (s->has_error) { DPRINTF("flush when error, bailing\n"); return -EINVAL; } DPRINTF("unfreezing output\n"); s->freeze_output = 0; buffered_flush(s); while (!s->freeze_output && offset < size) { if (s->bytes_xfer > s->xfer_limit) { DPRINTF("transfer limit exceeded when putting\n"); break; } ret = s->put_buffer(s->opaque, buf + offset, size - offset); if (ret == -EAGAIN) { DPRINTF("backend not ready, freezing\n"); s->freeze_output = 1; break; } if (ret <= 0) { DPRINTF("error putting\n"); s->has_error = 1; offset = -EINVAL; break; } DPRINTF("put %zd byte(s)\n", ret); offset += ret; s->bytes_xfer += ret; } if (offset >= 0) { DPRINTF("buffering %d bytes\n", size - offset); buffered_append(s, buf + offset, size - offset); offset = size; } if (pos == 0 && size == 0) { DPRINTF("file is ready\n"); if (s->bytes_xfer <= s->xfer_limit) { DPRINTF("notifying client\n"); s->put_ready(s->opaque); } } return offset; } static int buffered_close(void *opaque) { QEMUFileBuffered *s = opaque; int ret; DPRINTF("closing\n"); while (!s->has_error && s->buffer_size) { buffered_flush(s); if (s->freeze_output) s->wait_for_unfreeze(s); } ret = s->close(s->opaque); qemu_del_timer(s->timer); qemu_free_timer(s->timer); qemu_free(s->buffer); qemu_free(s); return ret; } static int buffered_rate_limit(void *opaque) { QEMUFileBuffered *s = opaque; if (s->has_error) return 0; if (s->freeze_output) return 1; if (s->bytes_xfer > s->xfer_limit) return 1; return 0; } static int64_t buffered_set_rate_limit(void *opaque, int64_t new_rate) { QEMUFileBuffered *s = opaque; if (s->has_error) goto out; if (new_rate > SIZE_MAX) { new_rate = SIZE_MAX; } s->xfer_limit = new_rate / 10; out: return s->xfer_limit; } static int64_t buffered_get_rate_limit(void *opaque) { QEMUFileBuffered *s = opaque; return s->xfer_limit; } static void buffered_rate_tick(void *opaque) { QEMUFileBuffered *s = opaque; if (s->has_error) { buffered_close(s); return; } qemu_mod_timer(s->timer, qemu_get_clock_ms(rt_clock) + 100); if (s->freeze_output) return; s->bytes_xfer = 0; buffered_flush(s); /* Add some checks around this */ s->put_ready(s->opaque); } QEMUFile *qemu_fopen_ops_buffered(void *opaque, size_t bytes_per_sec, BufferedPutFunc *put_buffer, BufferedPutReadyFunc *put_ready, BufferedWaitForUnfreezeFunc *wait_for_unfreeze, BufferedCloseFunc *close) { QEMUFileBuffered *s; s = qemu_mallocz(sizeof(*s)); s->opaque = opaque; s->xfer_limit = bytes_per_sec / 10; s->put_buffer = put_buffer; s->put_ready = put_ready; s->wait_for_unfreeze = wait_for_unfreeze; s->close = close; s->file = qemu_fopen_ops(s, buffered_put_buffer, NULL, buffered_close, buffered_rate_limit, buffered_set_rate_limit, buffered_get_rate_limit); s->timer = qemu_new_timer_ms(rt_clock, buffered_rate_tick, s); qemu_mod_timer(s->timer, qemu_get_clock_ms(rt_clock) + 100); return s->file; }