shell: Display errors from improperly-formatted command lines

diff --git a/shell.c b/shell.c
index 5b5e10501d58d5413e1673df2f1fd5a3ba948b3a..dea4cfdd2c230af6afd6233cacfa5c776a9962f9 100644 (file)
--- a/shell.c
+++ b/shell.c
@@ -2,8 +2,10 @@
 #include "quote.h"
 #include "exec_cmd.h"
 #include "strbuf.h"
+#include "run-command.h"
 
 #define COMMAND_DIR "git-shell-commands"
+#define HELP_COMMAND COMMAND_DIR "/help"
 
 static int do_generic_cmd(const char *me, char *arg)
 {
@@ -59,6 +61,63 @@ static void cd_to_homedir(void)
                die("could not chdir to user's home directory");
 }
 
+static void run_shell(void)
+{
+       int done = 0;
+       static const char *help_argv[] = { HELP_COMMAND, NULL };
+       /* Print help if enabled */
+       run_command_v_opt(help_argv, RUN_SILENT_EXEC_FAILURE);
+
+       do {
+               struct strbuf line = STRBUF_INIT;
+               const char *prog;
+               char *full_cmd;
+               char *rawargs;
+               char *split_args;
+               const char **argv;
+               int code;
+               int count;
+
+               fprintf(stderr, "git> ");
+               if (strbuf_getline(&line, stdin, '\n') == EOF) {
+                       fprintf(stderr, "\n");
+                       strbuf_release(&line);
+                       break;
+               }
+               strbuf_trim(&line);
+               rawargs = strbuf_detach(&line, NULL);
+               split_args = xstrdup(rawargs);
+               count = split_cmdline(split_args, &argv);
+               if (count < 0) {
+                       fprintf(stderr, "invalid command format '%s': %s\n", rawargs,
+                               split_cmdline_strerror(count));
+                       free(split_args);
+                       free(rawargs);
+                       continue;
+               }
+
+               prog = argv[0];
+               if (!strcmp(prog, "")) {
+               } else if (!strcmp(prog, "quit") || !strcmp(prog, "logout") ||
+                          !strcmp(prog, "exit") || !strcmp(prog, "bye")) {
+                       done = 1;
+               } else if (is_valid_cmd_name(prog)) {
+                       full_cmd = make_cmd(prog);
+                       argv[0] = full_cmd;
+                       code = run_command_v_opt(argv, RUN_SILENT_EXEC_FAILURE);
+                       if (code == -1 && errno == ENOENT) {
+                               fprintf(stderr, "unrecognized command '%s'\n", prog);
+                       }
+                       free(full_cmd);
+               } else {
+                       fprintf(stderr, "invalid command format '%s'\n", prog);
+               }
+
+               free(argv);
+               free(rawargs);
+       } while (!done);
+}
+
 static struct commands {
        const char *name;
        int (*exec)(const char *me, char *arg);
@@ -76,6 +135,7 @@ int main(int argc, char **argv)
        const char **user_argv;
        struct commands *cmd;
        int devnull_fd;
+       int count;
 
        /*
         * Always open file descriptors 0/1/2 to avoid clobbering files
@@ -92,15 +152,26 @@ int main(int argc, char **argv)
        /*
         * Special hack to pretend to be a CVS server
         */
-       if (argc == 2 && !strcmp(argv[1], "cvs server"))
+       if (argc == 2 && !strcmp(argv[1], "cvs server")) {
                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 == 1) {
+               /* Allow the user to run an interactive shell */
+               cd_to_homedir();
+               if (access(COMMAND_DIR, R_OK | X_OK) == -1) {
+                       die("Interactive git shell is not enabled.\n"
+                           "hint: ~/" COMMAND_DIR " should exist "
+                           "and have read and execute access.");
+               }
+               run_shell();
+               exit(0);
+       } else if (argc != 3 || strcmp(argv[1], "-c")) {
+               /*
+                * We do not accept any other modes except "-c" followed by
+                * "cmd arg", where "cmd" is a very limited subset of git
+                * commands or a command in the COMMAND_DIR
+                */
+               die("Run with no arguments or with -c cmd");
+       }
 
        prog = xstrdup(argv[2]);
        if (!strncmp(prog, "git", 3) && isspace(prog[3]))
@@ -127,7 +198,8 @@ int main(int argc, char **argv)
        }
 
        cd_to_homedir();
-       if (split_cmdline(prog, &user_argv) != -1) {
+       count = split_cmdline(prog, &user_argv);
+       if (count >= 0) {
                if (is_valid_cmd_name(user_argv[0])) {
                        prog = make_cmd(user_argv[0]);
                        user_argv[0] = prog;
@@ -138,6 +210,7 @@ int main(int argc, char **argv)
                die("unrecognized command '%s'", argv[2]);
        } else {
                free(prog);
-               die("invalid command format '%s'", argv[2]);
+               die("invalid command format '%s': %s", argv[2],
+                   split_cmdline_strerror(count));
        }
 }