qemu-char: Add new char backend CirMemCharDriver (51767e7c) · Commits · SUMMER2020 / students / proj-2021291

qemu-char.c

+114 −0

Original line number	Diff line number	Diff line
		@@ -98,6 +98,7 @@
		#include "ui/qemu-spice.h"

		#define READ_BUF_LEN 4096
		#define CBUFF_SIZE 65536

		/***********************************************************/
		/* character device */
		@@ -2643,6 +2644,110 @@ size_t qemu_chr_mem_osize(const CharDriverState *chr)
		return d->outbuf_size;
		}

		/*********************************************************/
		/CircularMemory chardev/

		typedef struct {
		size_t size;
		size_t prod;
		size_t cons;
		uint8_t *cbuf;
		} CirMemCharDriver;

		static bool cirmem_chr_is_empty(const CharDriverState *chr)
		{
		const CirMemCharDriver *d = chr->opaque;

		return d->cons == d->prod;
		}

		static size_t qemu_chr_cirmem_count(const CharDriverState *chr)
		{
		const CirMemCharDriver *d = chr->opaque;

		return (d->prod - d->cons);
		}

		static int cirmem_chr_write(CharDriverState chr, const uint8_t buf, int len)
		{
		CirMemCharDriver *d = chr->opaque;
		int i;

		if (!buf \|\| (len < 0)) {
		return -1;
		}

		for (i = 0; i < len; i++ ) {
		/* Avoid writing the IAC information to the queue. */
		if ((unsigned char)buf[i] == IAC) {
		continue;
		}

		d->cbuf[d->prod++ % d->size] = buf[i];
		if ((d->prod - d->cons) > d->size) {
		d->cons = d->prod - d->size;
		}
		}

		return 0;
		}

		static int cirmem_chr_read(CharDriverState chr, uint8_t buf, int len)
		{
		CirMemCharDriver *d = chr->opaque;
		int i;

		for (i = 0; i < len && !cirmem_chr_is_empty(chr); i++) {
		buf[i] = d->cbuf[d->cons++ % d->size];
		}

		return i;
		}

		static void cirmem_chr_close(struct CharDriverState *chr)
		{
		CirMemCharDriver *d = chr->opaque;

		g_free(d->cbuf);
		g_free(d);
		chr->opaque = NULL;
		}

		static CharDriverState qemu_chr_open_cirmemchr(QemuOpts opts)
		{
		CharDriverState *chr;
		CirMemCharDriver *d;

		chr = g_malloc0(sizeof(CharDriverState));
		d = g_malloc(sizeof(*d));

		d->size = qemu_opt_get_number(opts, "maxcapacity", 0);
		if (d->size == 0) {
		d->size = CBUFF_SIZE;
		}

		/* The size must be power of 2 */
		if (d->size & (d->size - 1)) {
		fprintf(stderr, "chardev: size of memory device must be power of 2\n");
		goto fail;
		}

		d->prod = 0;
		d->cons = 0;
		d->cbuf = g_malloc0(d->size);

		chr->opaque = d;
		chr->chr_write = cirmem_chr_write;
		chr->chr_close = cirmem_chr_close;

		return chr;

		fail:
		g_free(d);
		g_free(chr);
		return NULL;
		}

		QemuOpts qemu_chr_parse_compat(const char label, const char *filename)
		{
		char host[65], port[33], width[8], height[8];
		@@ -2697,6 +2802,11 @@ QemuOpts qemu_chr_parse_compat(const char label, const char *filename)
		qemu_opt_set(opts, "path", filename);
		return opts;
		}
		if (strstart(filename, "memory", &p)) {
		qemu_opt_set(opts, "backend", "memory");
		qemu_opt_set(opts, "maxcapacity", p);
		return opts;
		}
		if (strstart(filename, "file:", &p)) {
		qemu_opt_set(opts, "backend", "file");
		qemu_opt_set(opts, "path", p);
		@@ -2796,6 +2906,7 @@ static const struct {
		{ .name = "udp", .open = qemu_chr_open_udp },
		{ .name = "msmouse", .open = qemu_chr_open_msmouse },
		{ .name = "vc", .open = text_console_init },
		{ .name = "memory", .open = qemu_chr_open_cirmemchr },
		#ifdef _WIN32
		{ .name = "file", .open = qemu_chr_open_win_file_out },
		{ .name = "pipe", .open = qemu_chr_open_win_pipe },
		@@ -3055,6 +3166,9 @@ QemuOptsList qemu_chardev_opts = {
		},{
		.name = "debug",
		.type = QEMU_OPT_NUMBER,
		},{
		.name = "maxcapacity",
		.type = QEMU_OPT_NUMBER,
		},
		{ /* end of list */ }
		},

qemu-options.hx

+10 −0

Original line number	Diff line number	Diff line
		@@ -1736,6 +1736,7 @@ DEF("chardev", HAS_ARG, QEMU_OPTION_chardev,
		"-chardev msmouse,id=id[,mux=on\|off]\n"
		"-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]\n"
		" [,mux=on\|off]\n"
		"-chardev memory,id=id,maxcapacity=maxcapacity\n"
		"-chardev file,id=id,path=path[,mux=on\|off]\n"
		"-chardev pipe,id=id,path=path[,mux=on\|off]\n"
		#ifdef _WIN32
		@@ -1777,6 +1778,7 @@ Backend is one of:
		@option{udp},
		@option{msmouse},
		@option{vc},
		@option{memory},
		@option{file},
		@option{pipe},
		@option{console},
		@@ -1885,6 +1887,14 @@ the console, in pixels.
		@option{cols} and @option{rows} specify that the console be sized to fit a text
		console with the given dimensions.

		@item -chardev memory ,id=@var{id} ,maxcapacity=@var{maxcapacity}

		Create a circular buffer with fixed size indicated by optionally @option{maxcapacity}
		which will be default 64K if it is not given.

		@option{maxcapacity} specifies the max capacity of the size of circular buffer
		to create. Should be power of 2.

		@item -chardev file ,id=@var{id} ,path=@var{path}

		Log all traffic received from the guest to a file.