[PATCH v3 3/4] kvm tool: Provides the basic Gitish framework

[Prasad Joshi <prasadjoshi124@gmail.com>]

- kvm-cmd.h: Adds a new structure cmd_struct to create a table of commands
  and callback function. The structure was copied from tools/perf

- kvm-cmd.c: implements two main functions for command processing.
  kvm_get_command(): searches table for specific command.
  handle_command(): invokes the callback function for a given command.

- kvm-help.[ch] Implements the kvm help command. The function
  list_common_cmds_help() is a copy of similar function in tools/perf.

Signed-off-by: Prasad Joshi <prasadjoshi124@gmail.com>
---
 tools/kvm/include/kvm/kvm-cmd.h  |   12 ++++++++
 tools/kvm/include/kvm/kvm-help.h |    6 ++++
 tools/kvm/kvm-cmd.c              |   55 ++++++++++++++++++++++++++++++++++++++
 tools/kvm/kvm-help.c             |   43 +++++++++++++++++++++++++++++
 4 files changed, 116 insertions(+), 0 deletions(-)
 create mode 100644 tools/kvm/include/kvm/kvm-cmd.h
 create mode 100644 tools/kvm/include/kvm/kvm-help.h
 create mode 100644 tools/kvm/kvm-cmd.c
 create mode 100644 tools/kvm/kvm-help.c

diff --git a/tools/kvm/include/kvm/kvm-cmd.h b/tools/kvm/include/kvm/kvm-cmd.h
new file mode 100644
index 0000000..8d5fca5
--- /dev/null
+++ b/tools/kvm/include/kvm/kvm-cmd.h
@@ -0,0 +1,12 @@
+#ifndef __KVM_CMD_H__
+#define __KVM_CMD_H__
+
+struct cmd_struct {
+	const char *cmd;
+	int (*fn)(int, const char **, const char *);
+	int option;
+};
+
+int handle_command(struct cmd_struct *command, int argc, const char **argv);
+
+#endif
diff --git a/tools/kvm/include/kvm/kvm-help.h b/tools/kvm/include/kvm/kvm-help.h
new file mode 100644
index 0000000..2946743
--- /dev/null
+++ b/tools/kvm/include/kvm/kvm-help.h
@@ -0,0 +1,6 @@
+#ifndef __KVM_HELP_H__
+#define __KVM_HELP_H__
+
+int kvm_cmd_help(int argc, const char **argv, const char *prefix);
+
+#endif
diff --git a/tools/kvm/kvm-cmd.c b/tools/kvm/kvm-cmd.c
new file mode 100644
index 0000000..3c15006
--- /dev/null
+++ b/tools/kvm/kvm-cmd.c
@@ -0,0 +1,55 @@
+#include <stdio.h>
+#include <string.h>
+#include <errno.h>
+
+#include <assert.h>
+
+/* user defined header files */
+#include <kvm/kvm-cmd.h>
+
+/* kvm_get_command: Searches the command in an array of the commands and
+   returns a pointer to cmd_struct if a match is found.
+
+   Input parameters:
+   command: Array of possible commands. The last entry in the array must be
+            NULL.
+   cmd: A string command to search in the array
+
+   Return Value:
+   NULL: If the cmd is not matched with any of the command in the command array
+   p: Pointer to cmd_struct of the matching command
+ */
+static struct cmd_struct *kvm_get_command(struct cmd_struct *command,
+		const char *cmd)
+{
+	struct cmd_struct *p = command;
+
+	while (p->cmd) {
+		if (!strcmp(p->cmd, cmd))
+			return p;
+		p++;
+	}
+	return NULL;
+}
+
+int handle_command(struct cmd_struct *command, int argc, const char **argv)
+{
+	struct cmd_struct *p;
+	const char *prefix = NULL;
+
+	if (!argv || !*argv) {
+		p = kvm_get_command(command, "help");
+		assert(p);
+		return p->fn(argc, argv, prefix);
+	}
+
+	p = kvm_get_command(command, argv[0]);
+	if (!p) {
+		p = kvm_get_command(command, "help");
+		assert(p);
+		p->fn(0, NULL, prefix);
+		return EINVAL;
+	}
+
+	return p->fn(argc - 1, &argv[1], prefix);
+}
diff --git a/tools/kvm/kvm-help.c b/tools/kvm/kvm-help.c
new file mode 100644
index 0000000..5506807
--- /dev/null
+++ b/tools/kvm/kvm-help.c
@@ -0,0 +1,43 @@
+#include <stdio.h>
+#include <string.h>
+
+/* user defined headers */
+#include <common-cmds.h>
+
+#include <kvm/util.h>
+#include <kvm/kvm-help.h>
+
+
+const char kvm_usage_string[] =
+	"kvm [--version] [--help] COMMAND [ARGS]";
+
+const char kvm_more_info_string[] =
+	"See 'kvm help COMMAND' for more information on a specific command.";
+
+
+static void list_common_cmds_help(void)
+{
+	unsigned int i, longest = 0;
+
+	for (i = 0; i < ARRAY_SIZE(common_cmds); i++) {
+		if (longest < strlen(common_cmds[i].name))
+			longest = strlen(common_cmds[i].name);
+	}
+
+	puts(" The most commonly used kvm commands are:");
+	for (i = 0; i < ARRAY_SIZE(common_cmds); i++) {
+		printf("   %-*s   ", longest, common_cmds[i].name);
+		puts(common_cmds[i].help);
+	}
+}
+
+int kvm_cmd_help(int argc, const char **argv, const char *prefix)
+{
+	if (!argv || !*argv) {
+		printf("\n usage: %s\n\n", kvm_usage_string);
+		list_common_cmds_help();
+		printf("\n %s\n\n", kvm_more_info_string);
+		return 0;
+	}
+	return 0;
+}
-- 
1.7.1