* Re: [Qemu-devel] [patch] Remove requirement for -hda with -kernel
2005-04-28 19:53 ` Fabrice Bellard
@ 2005-04-29 0:47 ` Ross Kendall Axe
2005-04-29 21:56 ` Ross Kendall Axe
1 sibling, 0 replies; 4+ messages in thread
From: Ross Kendall Axe @ 2005-04-29 0:47 UTC (permalink / raw)
To: qemu-devel
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Fabrice Bellard wrote:
>
> Ross Kendall Axe wrote:
>
>> The requirement to provide an -hda argument when doing a direct boot of
>> a linux kernel has irritated me for some time. This patch removes that
>> requirement by creating a temporary 1 sector hda as needed.
>>
>> Ross
>
> I like the idea, but your patch may not compile for win32. Maybe
> creating a generic "dummy:[size]" block device would be interesting
> instead ?
>
> Fabrice.
Good point. It wouldn't compile, and, even if it did, it wouldn't run
correctly. Attached is a patch that *should* work.
The dummy block device idea is interesting. I'll see if I can implement
that; hopefully it won't be too difficult. However, IHMO a better,
albeit more ambitious solution would be to load the Linux boot code into
an emulated boot PROM.
Ross
[-- Attachment #1.2: qemu-linux-nohda-v2.patch --]
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Index: hw/pc.c
===================================================================
RCS file: /cvsroot/qemu/qemu/hw/pc.c,v
retrieving revision 1.35
diff -u -p -r1.35 pc.c
--- hw/pc.c 15 Jan 2005 12:02:56 -0000 1.35
+++ hw/pc.c 28 Apr 2005 23:36:13 -0000
@@ -446,8 +446,40 @@ void pc_init(int ram_size, int vga_ram_s
uint8_t old_bootsect[512];
if (bs_table[0] == NULL) {
- fprintf(stderr, "A disk image must be given for 'hda' when booting a Linux kernel\n");
- exit(1);
+#ifdef WIN32
+ char tmpfilename[L_tmpnam];
+#else
+ char tmpfilename[] = "/tmp/qemu.XXXXXX";
+ int tmpfilefd;
+#endif
+ FILE *tmpfile;
+
+ fprintf(stderr, "qemu: Disk image not given for 'hda' when booting"
+ " a Linux kernel; inventing one\n");
+#ifdef WIN32
+ tmpnam(tmpfilename);
+ tmpfile = fopen(tmpfilename, "wb");
+#else
+ tmpfilefd = mkstemp(tmpfilename);
+ tmpfile = (tmpfilefd == -1) ? NULL : fdopen(tmpfilefd, "wb");
+#endif
+ if(!tmpfile) {
+ fprintf(stderr, "qemu: couldn't create temporary diskimage\n");
+ exit(1);
+ }
+ fseek(tmpfile, 511, SEEK_SET);
+ fputc('0', tmpfile);
+ fclose(tmpfile);
+ bs_table[0] = bdrv_new("hda");
+ if (bdrv_open(bs_table[0], tmpfilename, 0) < 0) {
+ fprintf(stderr, "qemu: could not load temporary diskimage '%s'\n",
+ tmpfilename);
+ exit(1);
+ }
+#ifndef WIN32
+ unlink(tmpfilename);
+#endif
+ boot_device = 'c';
}
snprintf(buf, sizeof(buf), "%s/%s", bios_dir, LINUX_BOOT_FILENAME);
ret = load_image(buf, bootsect);
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^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [Qemu-devel] [patch] Remove requirement for -hda with -kernel
2005-04-28 19:53 ` Fabrice Bellard
2005-04-29 0:47 ` Ross Kendall Axe
@ 2005-04-29 21:56 ` Ross Kendall Axe
1 sibling, 0 replies; 4+ messages in thread
From: Ross Kendall Axe @ 2005-04-29 21:56 UTC (permalink / raw)
To: qemu-devel
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Fabrice Bellard wrote:
>
> I like the idea, but your patch may not compile for win32. Maybe
> creating a generic "dummy:[size]" block device would be interesting
> instead ?
>
> Fabrice.
>
How about this? With this patch you can specify e.g. '-hda dummy:256M'
to create a 256 Mb hard disc on the fly, backed by a file in the temp
directory which is deleted on exit. This patch uses this general
mechanism to create the bogus 1-sector hard disc needed for booting a
Linux kernel. This patch works on Linux and has been compile-tested on
Mingw.
Ross
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[-- Attachment #2: qemu-block-dummy.patch --]
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Index: Makefile
===================================================================
RCS file: /cvsroot/qemu/qemu/Makefile,v
retrieving revision 1.87
diff -u -p -r1.87 Makefile
--- Makefile 28 Apr 2005 21:15:08 -0000 1.87
+++ Makefile 29 Apr 2005 21:22:02 -0000
@@ -25,7 +25,7 @@ else
endif
endif
-qemu-img$(EXESUF): qemu-img.c block.c block-cow.c block-qcow.c aes.c block-vmdk.c block-cloop.c block-dmg.c block-bochs.c block-vpc.c block-vvfat.c
+qemu-img$(EXESUF): qemu-img.c block.c block-cow.c block-qcow.c aes.c block-vmdk.c block-cloop.c block-dmg.c block-bochs.c block-vpc.c block-vvfat.c block-dummy.c
$(CC) -DQEMU_TOOL $(CFLAGS) $(LDFLAGS) $(DEFINES) -o $@ $^ -lz $(LIBS)
dyngen$(EXESUF): dyngen.c
Index: Makefile.target
===================================================================
RCS file: /cvsroot/qemu/qemu/Makefile.target,v
retrieving revision 1.69
diff -u -p -r1.69 Makefile.target
--- Makefile.target 28 Apr 2005 21:15:08 -0000 1.69
+++ Makefile.target 29 Apr 2005 21:22:03 -0000
@@ -314,7 +314,7 @@ endif
# must use static linking to avoid leaving stuff in virtual address space
VL_OBJS=vl.o osdep.o block.o readline.o monitor.o pci.o console.o
-VL_OBJS+=block-cow.o block-qcow.o aes.o block-vmdk.o block-cloop.o block-dmg.o block-bochs.o block-vpc.o block-vvfat.o
+VL_OBJS+=block-cow.o block-qcow.o aes.o block-vmdk.o block-cloop.o block-dmg.o block-bochs.o block-vpc.o block-vvfat.o block-dummy.o
SOUND_HW = sb16.o
AUDIODRV = audio.o noaudio.o wavaudio.o
Index: block.c
===================================================================
RCS file: /cvsroot/qemu/qemu/block.c,v
retrieving revision 1.22
diff -u -p -r1.22 block.c
--- block.c 28 Apr 2005 21:09:32 -0000 1.22
+++ block.c 29 Apr 2005 21:22:05 -0000
@@ -657,4 +657,5 @@ void bdrv_init(void)
bdrv_register(&bdrv_bochs);
bdrv_register(&bdrv_vpc);
bdrv_register(&bdrv_vvfat);
+ bdrv_register(&bdrv_dummy);
}
Index: vl.h
===================================================================
RCS file: /cvsroot/qemu/qemu/vl.h,v
retrieving revision 1.73
diff -u -p -r1.73 vl.h
--- vl.h 28 Apr 2005 21:15:08 -0000 1.73
+++ vl.h 29 Apr 2005 21:22:08 -0000
@@ -385,6 +385,7 @@ extern BlockDriver bdrv_dmg;
extern BlockDriver bdrv_bochs;
extern BlockDriver bdrv_vpc;
extern BlockDriver bdrv_vvfat;
+extern BlockDriver bdrv_dummy;
void bdrv_init(void);
BlockDriver *bdrv_find_format(const char *format_name);
Index: hw/pc.c
===================================================================
RCS file: /cvsroot/qemu/qemu/hw/pc.c,v
retrieving revision 1.35
diff -u -p -r1.35 pc.c
--- hw/pc.c 15 Jan 2005 12:02:56 -0000 1.35
+++ hw/pc.c 29 Apr 2005 21:22:08 -0000
@@ -446,8 +446,14 @@ void pc_init(int ram_size, int vga_ram_s
uint8_t old_bootsect[512];
if (bs_table[0] == NULL) {
- fprintf(stderr, "A disk image must be given for 'hda' when booting a Linux kernel\n");
- exit(1);
+ fprintf(stderr, "qemu: Disk image not given for 'hda' when booting"
+ " a Linux kernel; inventing one\n");
+ bs_table[0] = bdrv_new("hda");
+ if (bdrv_open(bs_table[0], "dummy:512", 0) < 0) {
+ fprintf(stderr, "qemu: could not create temporary diskimage\n");
+ exit(1);
+ }
+ boot_device = 'c';
}
snprintf(buf, sizeof(buf), "%s/%s", bios_dir, LINUX_BOOT_FILENAME);
ret = load_image(buf, bootsect);
--- /dev/null 2005-04-29 15:39:30.000000000 +0100
+++ block-dummy.c 2005-04-29 21:48:18.000000000 +0100
@@ -0,0 +1,148 @@
+/*
+ * QEMU dummy block device driver
+ *
+ * Copyright (C) 2005 Ross Kendall Axe <ross.axe@blueyonder.co.uk>
+ * Portions copyright (c) 2003 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 "vl.h"
+#include "block_int.h"
+
+#define eprintf(...) fprintf(stderr, __VA_ARGS__)
+
+struct bdrv_dummy_state {
+ int fd;
+ char filename[PATH_MAX];
+};
+
+
+static int dummy_probe(const uint8_t *buf, int buf_size, const char *filename)
+{
+ return (0 == strncmp("dummy:", filename, 6)) ? 2 : 0;
+}
+
+static int dummy_open(BlockDriverState *bs, const char *filename)
+{
+ struct bdrv_dummy_state *s = bs->opaque;
+ off_t size;
+#ifdef WIN32
+ char tmpname[L_tmpnam];
+#else
+ char tmpname[] = "/tmp/qemu-dummy.XXXXXX";
+#endif
+ char *ptr;
+
+ size = strtoull(filename + 6, &ptr, 10);
+ if(ptr == (filename + 6)) {
+ eprintf("Size not given for dummy disc\n");
+ return -1;
+ }
+ switch(*ptr) {
+ case 't':
+ case 'T':
+ size *= 1024;
+ case 'g':
+ case 'G':
+ size *= 1024;
+ case 'm':
+ case 'M':
+ size *= 1024;
+ case 'k':
+ case 'K':
+ size *= 1024;
+ case 'b':
+ case 'B':
+ case '\0':
+ break;
+ default:
+ eprintf("Unknown multiplicative suffix '%s'\n", ptr);
+ return -1;
+ }
+
+#ifdef WIN32
+ if(tmpnam(tmpname))
+ s->fd = open(tmpname, O_RDWR | O_BINARY | O_LARGEFILE);
+ else
+ s->fd = -1;
+#else
+ s->fd = mkstemp(tmpname);
+#endif
+ if(s->fd < 0) {
+ perror("Couldn't create dummy disc image");
+ return -1;
+ }
+ s->filename[0] = '\0';
+ strncat(s->filename, tmpname, sizeof s->filename);
+
+ if(0 > ftruncate(s->fd, size)) {
+ perror("Couldn't size dummy disc image");
+ close(s->fd);
+ unlink(s->filename);
+ return -1;
+ }
+ bs->total_sectors = size / 512;
+ return 0;
+}
+
+static int dummy_read(BlockDriverState *bs, int64_t sector_num,
+ uint8_t *buf, int nb_sectors)
+{
+ struct bdrv_dummy_state *s = bs->opaque;
+ int ret;
+
+ lseek(s->fd, sector_num * 512, SEEK_SET);
+ ret = read(s->fd, buf, nb_sectors * 512);
+ if (ret != nb_sectors * 512)
+ return -1;
+ return 0;
+}
+
+static int dummy_write(BlockDriverState *bs, int64_t sector_num,
+ const uint8_t *buf, int nb_sectors)
+{
+ struct bdrv_dummy_state *s = bs->opaque;
+ int ret;
+
+ lseek(s->fd, sector_num * 512, SEEK_SET);
+ ret = write(s->fd, buf, nb_sectors * 512);
+ if (ret != nb_sectors * 512)
+ return -1;
+ return 0;
+}
+
+static void dummy_close(BlockDriverState *bs)
+{
+ struct bdrv_dummy_state *s = bs->opaque;
+
+ close(s->fd);
+ unlink(s->filename);
+}
+
+BlockDriver bdrv_dummy = {
+ "dummy",
+ sizeof (struct bdrv_dummy_state),
+ dummy_probe,
+ dummy_open,
+ dummy_read,
+ dummy_write,
+ dummy_close,
+ NULL,
+};
^ permalink raw reply [flat|nested] 4+ messages in thread