[PATCH/RFC 4/4] Add interactive mode to git-shell for user-friendliness

@@ -1,8 +1,11 @@
+#include <stdio.h>
+
 #include "cache.h"
 #include "quote.h"
 #include "exec_cmd.h"
 #include "strbuf.h"
 
+#define MAX_LINE_LEN 128
 #define COMMAND_DIR "git-shell-commands"
 
 static int do_generic_cmd(const char *me, char *arg)

@@ -41,6 +44,26 @@ static int is_valid_cmd_name(const char *cmd)
 	return cmd[strcspn(cmd, "./")] == '\0';
 }
 
+static int run(const char *prog)
+{
+	pid_t pid, res;
+	int w;
+	pid = fork();
+	if (pid == -1) {
+		perror("fork");
+		exit(-1);
+	} else if ( pid == 0 ) {
+		execl(prog, prog, (char *) NULL);
+		if (prog[0] != '\0')
+			fprintf(stderr, "unrecognized command '%s'\n", prog);
+		exit(127);
+	} else {
+		do {
+			res = waitpid (pid, &w, 0);
+		} while (res == -1 && errno == EINTR);
+	}
+}
+
 
 static struct commands {
 	const char *name;

@@ -56,6 +79,7 @@ static struct commands {
 int main(int argc, char **argv)
 {
 	char *prog;
+	char line[MAX_LINE_LEN];
 	struct commands *cmd;
 	int devnull_fd;
 

@@ -81,8 +105,30 @@ int main(int argc, char **argv)
 	 * We do not accept anything but "-c" followed by "cmd arg",
 	 * where "cmd" is a very limited subset of git commands.
 	 */
-	else if (argc != 3 || strcmp(argv[1], "-c"))
-		die("What do you think I am? A shell?");
+	else if (argc != 3 || strcmp(argv[1], "-c")) {
+		if (chdir(COMMAND_DIR))
+			die("Sorry, the interactive git-shell is not enabled");
+		for (;;) {
+			printf("git> ");
+			if (fgets(line, MAX_LINE_LEN, stdin) == NULL) {
+				printf("\n");
+				exit(0);
+			}
+
+			if (line[strlen(line) - 1] == '\n')
+				line[strlen(line) - 1] = '\0';
+
+			if (!strcmp(line, "quit") || !strcmp(line, "logout") ||
+				   !strcmp(line, "exit")) {
+				exit(0);
+			} else if (!strcmp(line, "")) {
+			} else if (is_valid_cmd_name(line)) {
+				run(line);
+			} else {
+				fprintf(stderr, "invalid command format '%s'\n", line);
+			}
+		};
+	}
 
 	prog = argv[2];
 	if (!strncmp(prog, "git", 3) && isspace(prog[3]))