diff mbox

[3/9] kvm tools: Allow giving instance names

Message ID 1309370538-7947-3-git-send-email-levinsasha928@gmail.com (mailing list archive)
State New, archived
Headers show

Commit Message

Sasha Levin June 29, 2011, 6:02 p.m. UTC
This will allow tracking instance names and sending commands
to specific instances if multiple instances are running.

Signed-off-by: Sasha Levin <levinsasha928@gmail.com>
---
 tools/kvm/include/kvm/kvm.h |    5 +++-
 tools/kvm/kvm-run.c         |    5 +++-
 tools/kvm/kvm.c             |   55 ++++++++++++++++++++++++++++++++++++++++++-
 tools/kvm/term.c            |    3 ++
 4 files changed, 65 insertions(+), 3 deletions(-)

Comments

Pekka Enberg June 30, 2011, 7:53 a.m. UTC | #1
On Wed, 29 Jun 2011, Sasha Levin wrote:
> This will allow tracking instance names and sending commands
> to specific instances if multiple instances are running.
>
> Signed-off-by: Sasha Levin <levinsasha928@gmail.com>

I skipped this and related patches because I really would like to hear 
what Ingo thinks about the '/var/run/kvm-tools/' pidfile mechanism.

> ---
> tools/kvm/include/kvm/kvm.h |    5 +++-
> tools/kvm/kvm-run.c         |    5 +++-
> tools/kvm/kvm.c             |   55 ++++++++++++++++++++++++++++++++++++++++++-
> tools/kvm/term.c            |    3 ++
> 4 files changed, 65 insertions(+), 3 deletions(-)
>
> diff --git a/tools/kvm/include/kvm/kvm.h b/tools/kvm/include/kvm/kvm.h
> index 7d90d35..5ad3236 100644
> --- a/tools/kvm/include/kvm/kvm.h
> +++ b/tools/kvm/include/kvm/kvm.h
> @@ -41,9 +41,11 @@ struct kvm {
> 	const char		*vmlinux;
> 	struct disk_image       **disks;
> 	int                     nr_disks;
> +
> +	const char		*name;
> };
>
> -struct kvm *kvm__init(const char *kvm_dev, u64 ram_size);
> +struct kvm *kvm__init(const char *kvm_dev, u64 ram_size, const char *name);
> int kvm__max_cpus(struct kvm *kvm);
> void kvm__init_ram(struct kvm *kvm);
> void kvm__delete(struct kvm *kvm);
> @@ -61,6 +63,7 @@ bool kvm__deregister_mmio(struct kvm *kvm, u64 phys_addr);
> void kvm__pause(void);
> void kvm__continue(void);
> void kvm__notify_paused(void);
> +int kvm__get_pid_by_instance(const char *name);
>
> /*
>  * Debugging
> diff --git a/tools/kvm/kvm-run.c b/tools/kvm/kvm-run.c
> index 0dece2d..a4abf76 100644
> --- a/tools/kvm/kvm-run.c
> +++ b/tools/kvm/kvm-run.c
> @@ -69,6 +69,7 @@ static const char *network;
> static const char *host_ip_addr;
> static const char *guest_mac;
> static const char *script;
> +static const char *guest_name;
> static bool single_step;
> static bool readonly_image[MAX_DISK_IMAGES];
> static bool vnc;
> @@ -132,6 +133,8 @@ static int virtio_9p_rootdir_parser(const struct option *opt, const char *arg, i
>
> static const struct option options[] = {
> 	OPT_GROUP("Basic options:"),
> +	OPT_STRING('\0', "name", &guest_name, "guest name",
> +			"A name for the guest"),
> 	OPT_INTEGER('c', "cpus", &nrcpus, "Number of CPUs"),
> 	OPT_U64('m', "mem", &ram_size, "Virtual machine memory size in MiB."),
> 	OPT_CALLBACK('d', "disk", NULL, "image", "Disk image", img_name_parser),
> @@ -546,7 +549,7 @@ int kvm_cmd_run(int argc, const char **argv, const char *prefix)
>
> 	term_init();
>
> -	kvm = kvm__init(kvm_dev, ram_size);
> +	kvm = kvm__init(kvm_dev, ram_size, guest_name);
>
> 	ioeventfd__init();
>
> diff --git a/tools/kvm/kvm.c b/tools/kvm/kvm.c
> index c400c70..4f723a6 100644
> --- a/tools/kvm/kvm.c
> +++ b/tools/kvm/kvm.c
> @@ -113,11 +113,60 @@ static struct kvm *kvm__new(void)
> 	return kvm;
> }
>
> +static void kvm__create_pidfile(struct kvm *kvm)
> +{
> +	int fd;
> +	char full_name[PATH_MAX], pid[10];
> +
> +	if (!kvm->name)
> +		return;
> +
> +	mkdir("/var/run/kvm-tools", 0777);

mkdir() can fail

> +	sprintf(full_name, "/var/run/kvm-tools/%s.pid", kvm->name);
> +	fd = open(full_name, O_CREAT | O_WRONLY, 0666);
> +	sprintf(pid, "%u\n", getpid());
> +	if (write(fd, pid, strlen(pid)) <= 0)
> +		die("Failed creating PID file");
> +	close(fd);
> +}
> +
> +static void kvm__remove_pidfile(struct kvm *kvm)
> +{
> +	char full_name[PATH_MAX];
> +
> +	if (!kvm->name)
> +		return;
> +
> +	sprintf(full_name, "/var/run/kvm-tools/%s.pid", kvm->name);
> +	unlink(full_name);

unlink() can fail too - dunno if it matters in practice but there 
shouldn't be harm in checking for it?

> +}
> +
> +int kvm__get_pid_by_instance(const char *name)
> +{
> +	int fd, pid;
> +	char pid_str[10], pid_file[PATH_MAX];
> +
> +	sprintf(pid_file, "/var/run/kvm-tools/%s.pid", name);
> +	fd = open(pid_file, O_RDONLY);
> +	if (fd < 0)
> +		return -1;
> +
> +	if (read(fd, pid_str, 10) == 0)
> +		return -1;
> +
> +	pid = atoi(pid_str);
> +	if (pid < 0)
> +		return -1;
> +
> +	return pid;
> +}
> +
> void kvm__delete(struct kvm *kvm)
> {
> 	kvm__stop_timer(kvm);
>
> 	munmap(kvm->ram_start, kvm->ram_size);
> +	kvm__remove_pidfile(kvm);
> 	free(kvm);
> }
>
> @@ -237,7 +286,7 @@ int kvm__max_cpus(struct kvm *kvm)
> 	return ret;
> }
>
> -struct kvm *kvm__init(const char *kvm_dev, u64 ram_size)
> +struct kvm *kvm__init(const char *kvm_dev, u64 ram_size, const char *name)
> {
> 	struct kvm_pit_config pit_config = { .flags = 0, };
> 	struct kvm *kvm;
> @@ -300,6 +349,10 @@ struct kvm *kvm__init(const char *kvm_dev, u64 ram_size)
> 	if (ret < 0)
> 		die_perror("KVM_CREATE_IRQCHIP ioctl");
>
> +	kvm->name = name;
> +
> +	kvm__create_pidfile(kvm);
> +
> 	return kvm;
> }
>
> diff --git a/tools/kvm/term.c b/tools/kvm/term.c
> index 9947223..a0cb03f 100644
> --- a/tools/kvm/term.c
> +++ b/tools/kvm/term.c
> @@ -9,7 +9,9 @@
> #include "kvm/read-write.h"
> #include "kvm/term.h"
> #include "kvm/util.h"
> +#include "kvm/kvm.h"
>
> +extern struct kvm *kvm;
> static struct termios	orig_term;
>
> int term_escape_char	= 0x01; /* ctrl-a is used for escape */
> @@ -32,6 +34,7 @@ int term_getc(int who)
> 	if (term_got_escape) {
> 		term_got_escape = false;
> 		if (c == 'x') {
> +			kvm__delete(kvm);
> 			printf("\n  # KVM session terminated.\n");
> 			exit(1);
> 		}
> -- 
> 1.7.6
>
>
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Sasha Levin June 30, 2011, 3 p.m. UTC | #2
On Thu, 2011-06-30 at 11:30 +0300, Avi Kivity wrote:
> On 06/30/2011 10:53 AM, Pekka Enberg wrote:
> > On Wed, 29 Jun 2011, Sasha Levin wrote:
> >> This will allow tracking instance names and sending commands
> >> to specific instances if multiple instances are running.
> >>
> >> Signed-off-by: Sasha Levin <levinsasha928@gmail.com>
> >
> > I skipped this and related patches because I really would like to hear 
> > what Ingo thinks about the '/var/run/kvm-tools/' pidfile mechanism.
> 
> Isn't it root-only?  I think something like ~/.kvm-tools/ is better.
> 

Yes. I completely forgot about permissions required for /var/run.
Avi Kivity June 30, 2011, 3:03 p.m. UTC | #3
On 06/30/2011 06:00 PM, Sasha Levin wrote:
> On Thu, 2011-06-30 at 11:30 +0300, Avi Kivity wrote:
> >  On 06/30/2011 10:53 AM, Pekka Enberg wrote:
> >  >  On Wed, 29 Jun 2011, Sasha Levin wrote:
> >  >>  This will allow tracking instance names and sending commands
> >  >>  to specific instances if multiple instances are running.
> >  >>
> >  >>  Signed-off-by: Sasha Levin<levinsasha928@gmail.com>
> >  >
> >  >  I skipped this and related patches because I really would like to hear
> >  >  what Ingo thinks about the '/var/run/kvm-tools/' pidfile mechanism.
> >
> >  Isn't it root-only?  I think something like ~/.kvm-tools/ is better.
> >
>
> Yes. I completely forgot about permissions required for /var/run.

It's best to run kvm as an ordinary user, so your users don't get surprised.
diff mbox

Patch

diff --git a/tools/kvm/include/kvm/kvm.h b/tools/kvm/include/kvm/kvm.h
index 7d90d35..5ad3236 100644
--- a/tools/kvm/include/kvm/kvm.h
+++ b/tools/kvm/include/kvm/kvm.h
@@ -41,9 +41,11 @@  struct kvm {
 	const char		*vmlinux;
 	struct disk_image       **disks;
 	int                     nr_disks;
+
+	const char		*name;
 };
 
-struct kvm *kvm__init(const char *kvm_dev, u64 ram_size);
+struct kvm *kvm__init(const char *kvm_dev, u64 ram_size, const char *name);
 int kvm__max_cpus(struct kvm *kvm);
 void kvm__init_ram(struct kvm *kvm);
 void kvm__delete(struct kvm *kvm);
@@ -61,6 +63,7 @@  bool kvm__deregister_mmio(struct kvm *kvm, u64 phys_addr);
 void kvm__pause(void);
 void kvm__continue(void);
 void kvm__notify_paused(void);
+int kvm__get_pid_by_instance(const char *name);
 
 /*
  * Debugging
diff --git a/tools/kvm/kvm-run.c b/tools/kvm/kvm-run.c
index 0dece2d..a4abf76 100644
--- a/tools/kvm/kvm-run.c
+++ b/tools/kvm/kvm-run.c
@@ -69,6 +69,7 @@  static const char *network;
 static const char *host_ip_addr;
 static const char *guest_mac;
 static const char *script;
+static const char *guest_name;
 static bool single_step;
 static bool readonly_image[MAX_DISK_IMAGES];
 static bool vnc;
@@ -132,6 +133,8 @@  static int virtio_9p_rootdir_parser(const struct option *opt, const char *arg, i
 
 static const struct option options[] = {
 	OPT_GROUP("Basic options:"),
+	OPT_STRING('\0', "name", &guest_name, "guest name",
+			"A name for the guest"),
 	OPT_INTEGER('c', "cpus", &nrcpus, "Number of CPUs"),
 	OPT_U64('m', "mem", &ram_size, "Virtual machine memory size in MiB."),
 	OPT_CALLBACK('d', "disk", NULL, "image", "Disk image", img_name_parser),
@@ -546,7 +549,7 @@  int kvm_cmd_run(int argc, const char **argv, const char *prefix)
 
 	term_init();
 
-	kvm = kvm__init(kvm_dev, ram_size);
+	kvm = kvm__init(kvm_dev, ram_size, guest_name);
 
 	ioeventfd__init();
 
diff --git a/tools/kvm/kvm.c b/tools/kvm/kvm.c
index c400c70..4f723a6 100644
--- a/tools/kvm/kvm.c
+++ b/tools/kvm/kvm.c
@@ -113,11 +113,60 @@  static struct kvm *kvm__new(void)
 	return kvm;
 }
 
+static void kvm__create_pidfile(struct kvm *kvm)
+{
+	int fd;
+	char full_name[PATH_MAX], pid[10];
+
+	if (!kvm->name)
+		return;
+
+	mkdir("/var/run/kvm-tools", 0777);
+	sprintf(full_name, "/var/run/kvm-tools/%s.pid", kvm->name);
+	fd = open(full_name, O_CREAT | O_WRONLY, 0666);
+	sprintf(pid, "%u\n", getpid());
+	if (write(fd, pid, strlen(pid)) <= 0)
+		die("Failed creating PID file");
+	close(fd);
+}
+
+static void kvm__remove_pidfile(struct kvm *kvm)
+{
+	char full_name[PATH_MAX];
+
+	if (!kvm->name)
+		return;
+
+	sprintf(full_name, "/var/run/kvm-tools/%s.pid", kvm->name);
+	unlink(full_name);
+}
+
+int kvm__get_pid_by_instance(const char *name)
+{
+	int fd, pid;
+	char pid_str[10], pid_file[PATH_MAX];
+
+	sprintf(pid_file, "/var/run/kvm-tools/%s.pid", name);
+	fd = open(pid_file, O_RDONLY);
+	if (fd < 0)
+		return -1;
+
+	if (read(fd, pid_str, 10) == 0)
+		return -1;
+
+	pid = atoi(pid_str);
+	if (pid < 0)
+		return -1;
+
+	return pid;
+}
+
 void kvm__delete(struct kvm *kvm)
 {
 	kvm__stop_timer(kvm);
 
 	munmap(kvm->ram_start, kvm->ram_size);
+	kvm__remove_pidfile(kvm);
 	free(kvm);
 }
 
@@ -237,7 +286,7 @@  int kvm__max_cpus(struct kvm *kvm)
 	return ret;
 }
 
-struct kvm *kvm__init(const char *kvm_dev, u64 ram_size)
+struct kvm *kvm__init(const char *kvm_dev, u64 ram_size, const char *name)
 {
 	struct kvm_pit_config pit_config = { .flags = 0, };
 	struct kvm *kvm;
@@ -300,6 +349,10 @@  struct kvm *kvm__init(const char *kvm_dev, u64 ram_size)
 	if (ret < 0)
 		die_perror("KVM_CREATE_IRQCHIP ioctl");
 
+	kvm->name = name;
+
+	kvm__create_pidfile(kvm);
+
 	return kvm;
 }
 
diff --git a/tools/kvm/term.c b/tools/kvm/term.c
index 9947223..a0cb03f 100644
--- a/tools/kvm/term.c
+++ b/tools/kvm/term.c
@@ -9,7 +9,9 @@ 
 #include "kvm/read-write.h"
 #include "kvm/term.h"
 #include "kvm/util.h"
+#include "kvm/kvm.h"
 
+extern struct kvm *kvm;
 static struct termios	orig_term;
 
 int term_escape_char	= 0x01; /* ctrl-a is used for escape */
@@ -32,6 +34,7 @@  int term_getc(int who)
 	if (term_got_escape) {
 		term_got_escape = false;
 		if (c == 'x') {
+			kvm__delete(kvm);
 			printf("\n  # KVM session terminated.\n");
 			exit(1);
 		}