mirror of
https://github.com/clearlinux/kvmtool.git
synced 2026-06-16 02:15:47 +00:00
kvm tools: Introduce 'kvm setup' command
This patch implements 'kvm setup' command that can be used to setup a guest filesystem that shares system libraries and binaries from host filesystem in read-only mode. You can setup a new shared rootfs guest with: ./kvm setup -n default and launch it with: ./kvm run --9p /,hostfs -p "init=virt/init" -d ~/.kvm-tools/default/ We want to teach 'kvm run' to be able to launch guest filesystems by name in the future. Furthermore, 'kvm run' should setup a 'default' filesystem and use it by default unless the user specifies otherwise. Cc: Asias He <asias.hejun@gmail.com> Cc: Cyrill Gorcunov <gorcunov@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Sasha Levin <levinsasha928@gmail.com> Signed-off-by: Pekka Enberg <penberg@kernel.org>
This commit is contained in:
Pekka Enberg
committed by
Will Deacon
Will Deacon
parent
06f4810348
commit
282113fd51
@@ -6,4 +6,5 @@ tags
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include/common-cmds.h
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tests/boot/boot_test.iso
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tests/boot/rootfs/
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guest/init
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KVMTOOLS-VERSION-FILE
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@@ -0,0 +1,15 @@
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kvm-setup(1)
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================
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NAME
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----
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kvm-setup - Setup a new virtual machine
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SYNOPSIS
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--------
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[verse]
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'kvm setup <name>'
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DESCRIPTION
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-----------
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The command setups a virtual machine.
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@@ -20,6 +20,8 @@ TAGS := ctags
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PROGRAM := kvm
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GUEST_INIT := guest/init
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OBJS += builtin-balloon.o
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OBJS += builtin-debug.o
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OBJS += builtin-help.o
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@@ -28,6 +30,7 @@ OBJS += builtin-stat.o
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OBJS += builtin-pause.o
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OBJS += builtin-resume.o
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OBJS += builtin-run.o
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OBJS += builtin-setup.o
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OBJS += builtin-stop.o
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OBJS += builtin-version.o
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OBJS += cpuid.o
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@@ -159,7 +162,7 @@ WARNINGS += -Wunused-result
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CFLAGS += $(WARNINGS)
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all: $(PROGRAM)
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all: $(PROGRAM) $(GUEST_INIT)
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KVMTOOLS-VERSION-FILE:
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@$(SHELL_PATH) util/KVMTOOLS-VERSION-GEN $(OUTPUT)
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@@ -169,6 +172,10 @@ $(PROGRAM): $(DEPS) $(OBJS)
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$(E) " LINK " $@
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$(Q) $(CC) $(OBJS) $(LIBS) -o $@
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$(GUEST_INIT): guest/init.c
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$(E) " LINK " $@
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$(Q) $(CC) -static guest/init.c -o $@
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$(DEPS):
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%.d: %.c
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@@ -240,7 +247,7 @@ clean:
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$(Q) rm -f bios/bios-rom.h
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$(Q) rm -f tests/boot/boot_test.iso
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$(Q) rm -rf tests/boot/rootfs/
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$(Q) rm -f $(DEPS) $(OBJS) $(PROGRAM)
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$(Q) rm -f $(DEPS) $(OBJS) $(PROGRAM) $(GUEST_INIT)
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$(Q) rm -f cscope.*
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$(Q) rm -f $(KVM_INCLUDE)/common-cmds.h
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$(Q) rm -f KVMTOOLS-VERSION-FILE
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+185
@@ -0,0 +1,185 @@
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#include <kvm/util.h>
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#include <kvm/kvm-cmd.h>
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#include <kvm/builtin-setup.h>
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#include <kvm/kvm.h>
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#include <kvm/parse-options.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <limits.h>
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#include <signal.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include <stdio.h>
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#include <sys/types.h>
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#include <sys/mman.h>
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#include <sys/stat.h>
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#include <string.h>
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#include <unistd.h>
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#include <fcntl.h>
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#define KVM_PID_FILE_PATH "/.kvm-tools/"
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#define HOME_DIR getenv("HOME")
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static const char *instance_name;
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static const char * const setup_usage[] = {
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"kvm setup [-n name]",
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NULL
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};
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static const struct option setup_options[] = {
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OPT_GROUP("General options:"),
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OPT_STRING('n', "name", &instance_name, "name", "Instance name"),
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OPT_END()
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};
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static void parse_setup_options(int argc, const char **argv)
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{
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while (argc != 0) {
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argc = parse_options(argc, argv, setup_options, setup_usage,
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PARSE_OPT_STOP_AT_NON_OPTION);
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if (argc != 0)
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kvm_setup_help();
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}
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}
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void kvm_setup_help(void)
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{
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usage_with_options(setup_usage, setup_options);
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}
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static int copy_file(const char *from, const char *to)
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{
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int in_fd, out_fd;
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void *src, *dst;
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struct stat st;
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int err = -1;
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in_fd = open(from, O_RDONLY);
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if (in_fd < 0)
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return err;
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if (fstat(in_fd, &st) < 0)
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goto error_close_in;
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out_fd = open(to, O_RDWR | O_CREAT | O_TRUNC, st.st_mode & (S_IRWXU|S_IRWXG|S_IRWXO));
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if (out_fd < 0)
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goto error_close_in;
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src = mmap(NULL, st.st_size, PROT_READ, MAP_SHARED, in_fd, 0);
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if (src == MAP_FAILED)
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goto error_close_out;
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if (ftruncate(out_fd, st.st_size) < 0)
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goto error_munmap_src;
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dst = mmap(NULL, st.st_size, PROT_READ|PROT_WRITE, MAP_SHARED, out_fd, 0);
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if (dst == MAP_FAILED)
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goto error_munmap_src;
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memcpy(dst, src, st.st_size);
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if (fsync(out_fd) < 0)
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goto error_munmap_dst;
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err = 0;
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error_munmap_dst:
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munmap(dst, st.st_size);
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error_munmap_src:
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munmap(src, st.st_size);
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error_close_out:
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close(out_fd);
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error_close_in:
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close(in_fd);
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return err;
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}
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static const char *guestfs_dirs[] = {
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"/dev",
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"/etc",
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"/home",
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"/host",
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"/proc",
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"/root",
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"/sys",
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"/var",
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"/var/lib",
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"/virt",
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};
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static const char *guestfs_symlinks[] = {
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"/bin",
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"/lib",
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"/lib64",
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"/sbin",
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"/usr",
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};
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static int copy_init(const char *guestfs_name)
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{
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char path[PATH_MAX];
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snprintf(path, PATH_MAX, "%s%s%s/virt/init", HOME_DIR, KVM_PID_FILE_PATH, guestfs_name);
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return copy_file("guest/init", path);
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}
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static int make_guestfs_symlink(const char *guestfs_name, const char *path)
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{
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char target[PATH_MAX];
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char name[PATH_MAX];
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snprintf(name, PATH_MAX, "%s%s%s%s", HOME_DIR, KVM_PID_FILE_PATH, guestfs_name, path);
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snprintf(target, PATH_MAX, "/host%s", path);
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return symlink(target, name);
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}
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static void make_dir(const char *dir)
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{
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char name[PATH_MAX];
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snprintf(name, PATH_MAX, "%s%s%s", HOME_DIR, KVM_PID_FILE_PATH, dir);
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mkdir(name, 0777);
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}
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static void make_guestfs_dir(const char *guestfs_name, const char *dir)
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{
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char name[PATH_MAX];
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snprintf(name, PATH_MAX, "%s%s", guestfs_name, dir);
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make_dir(name);
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}
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static int do_setup(const char *guestfs_name)
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{
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unsigned int i;
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make_dir(guestfs_name);
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for (i = 0; i < ARRAY_SIZE(guestfs_dirs); i++)
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make_guestfs_dir(guestfs_name, guestfs_dirs[i]);
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for (i = 0; i < ARRAY_SIZE(guestfs_symlinks); i++) {
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make_guestfs_symlink(guestfs_name, guestfs_symlinks[i]);
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}
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return copy_init(guestfs_name);
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}
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int kvm_cmd_setup(int argc, const char **argv, const char *prefix)
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{
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parse_setup_options(argc, argv);
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if (instance_name == NULL)
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kvm_setup_help();
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return do_setup(instance_name);
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}
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@@ -3,6 +3,7 @@
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# command name category [deprecated] [common]
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#
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kvm-run mainporcelain common
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kvm-setup mainporcelain common
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kvm-pause common
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kvm-resume common
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kvm-version common
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@@ -0,0 +1,40 @@
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/*
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* This is a simple init for shared rootfs guests. It brings up critical
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* mountpoints and then launches /bin/sh.
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*/
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#include <sys/mount.h>
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#include <string.h>
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#include <unistd.h>
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#include <stdio.h>
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#include <errno.h>
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static int run_process(char *filename)
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{
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char *new_argv[] = { filename, NULL };
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char *new_env[] = { NULL };
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return execve(filename, new_argv, new_env);
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}
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static void do_mounts(void)
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{
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mount("hostfs", "/host", "9p", MS_RDONLY, "trans=virtio,version=9p2000.L");
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mount("", "/sys", "sysfs", 0, NULL);
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mount("proc", "/proc", "proc", 0, NULL);
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mount("devtmpfs", "/dev", "devtmpfs", 0, NULL);
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}
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int main(int argc, char *argv[])
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{
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puts("Mounting...");
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do_mounts();
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puts("Starting '/bin/sh'...");
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run_process("/bin/sh");
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printf("Init failed: %s\n", strerror(errno));
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return 0;
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}
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@@ -0,0 +1,7 @@
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#ifndef KVM__SETUP_H
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#define KVM__SETUP_H
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int kvm_cmd_setup(int argc, const char **argv, const char *prefix);
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void kvm_setup_help(void);
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#endif
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@@ -11,6 +11,7 @@
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#include "kvm/builtin-balloon.h"
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#include "kvm/builtin-list.h"
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#include "kvm/builtin-version.h"
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#include "kvm/builtin-setup.h"
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#include "kvm/builtin-stop.h"
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#include "kvm/builtin-stat.h"
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#include "kvm/builtin-help.h"
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@@ -29,6 +30,7 @@ struct cmd_struct kvm_commands[] = {
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{ "stop", kvm_cmd_stop, kvm_stop_help, 0 },
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{ "stat", kvm_cmd_stat, kvm_stat_help, 0 },
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{ "help", kvm_cmd_help, NULL, 0 },
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{ "setup", kvm_cmd_setup, kvm_setup_help, 0 },
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{ "run", kvm_cmd_run, kvm_run_help, 0 },
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{ NULL, NULL, NULL, 0 },
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};
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