unpack_object_header_buffer(): clear the size field upon error
[gitweb.git] / shell.c
diff --git a/shell.c b/shell.c
index e4864e04da3b0e237342c2ca0548c0ec0082c171..abb862246ef01743424e4a447ee169f3fdbb9f51 100644 (file)
--- a/shell.c
+++ b/shell.c
@@ -2,6 +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)
 {
@@ -33,6 +37,86 @@ static int do_cvs_cmd(const char *me, char *arg)
        return execv_git_cmd(cvsserver_argv);
 }
 
+static int is_valid_cmd_name(const char *cmd)
+{
+       /* Test command contains no . or / characters */
+       return cmd[strcspn(cmd, "./")] == '\0';
+}
+
+static char *make_cmd(const char *prog)
+{
+       char *prefix = xmalloc((strlen(prog) + strlen(COMMAND_DIR) + 2));
+       strcpy(prefix, COMMAND_DIR);
+       strcat(prefix, "/");
+       strcat(prefix, prog);
+       return prefix;
+}
+
+static void cd_to_homedir(void)
+{
+       const char *home = getenv("HOME");
+       if (!home)
+               die("could not determine user's home directory; HOME is unset");
+       if (chdir(home) == -1)
+               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;
@@ -48,8 +132,12 @@ static struct commands {
 int main(int argc, char **argv)
 {
        char *prog;
+       const char **user_argv;
        struct commands *cmd;
        int devnull_fd;
+       int count;
+
+       git_extract_argv0_path(argv[0]);
 
        /*
         * Always open file descriptors 0/1/2 to avoid clobbering files
@@ -66,17 +154,28 @@ 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--;
+       } 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");
+       }
 
-       /*
-        * 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?");
-
-       prog = argv[2];
+       prog = xstrdup(argv[2]);
        if (!strncmp(prog, "git", 3) && isspace(prog[3]))
                /* Accept "git foo" as if the caller said "git-foo". */
                prog[3] = '-';
@@ -99,5 +198,21 @@ int main(int argc, char **argv)
                }
                exit(cmd->exec(cmd->name, arg));
        }
-       die("unrecognized command '%s'", prog);
+
+       cd_to_homedir();
+       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;
+                       execv(user_argv[0], (char *const *) user_argv);
+               }
+               free(prog);
+               free(user_argv);
+               die("unrecognized command '%s'", argv[2]);
+       } else {
+               free(prog);
+               die("invalid command format '%s': %s", argv[2],
+                   split_cmdline_strerror(count));
+       }
 }