Adding the option to select the group by name

src/includes.h

@@ -47,6 +47,7 @@
 #include <sys/stat.h>
 #include <sys/statvfs.h>
 #include <ctype.h>
+#include <grp.h>
 
 #define OFF_FMT "%lu"
 #define INO_FMT "%lu"
@@ -106,6 +107,7 @@ struct fs_config {
 
   uid_t uid;
   gid_t gid;
+  char* group_name;
   time_t mounted_at;
   int direct_io;
 

src/main.c

@@ -41,6 +41,7 @@ static void usage(struct fuse_args *args)
 "    -o dotdot              Shows '.' and '..' directories [default: ignored]\n"
 "    -o user_id=N           user id of the mount point [default: caller's uid]\n"
 "    -o group_id=N          group id of the mount point [default: caller's gid]\n"
+"    -o group_name=S        group name of the mount point [overwrites group_id]\n"
 "\n"
 "Crypt4GH Options (if enabled):\n"
 "    -o seckey=<path>       Absolute path to the Crypt4GH secret key\n"
@@ -76,6 +77,7 @@ static struct fuse_opt fs_opts[] = {
 	/* Mount group id */
 	CRYPT4GH_SQLITE_OPT("user_id=%u", uid, 0), // chill... it's not root
 	CRYPT4GH_SQLITE_OPT("group_id=%u", gid, 0),
+	CRYPT4GH_SQLITE_OPT("group_name=%s", group_name, 0),
 
 	/* in case Crypt4GH is enabled */
 	CRYPT4GH_SQLITE_OPT("seckey=%s"             , seckeypath         , 0),
@@ -140,7 +142,6 @@ fs_opt_proc(void *data, const char *arg, int key, struct fuse_args *outargs)
 	}
 }
 
-
 static int
 read_passphrase(const char* prompt)
 {
@@ -335,6 +336,21 @@ int main(int argc, char *argv[])
       exit(1);
     }
 
+  if ( config.group_name )
+    {
+      //errno = 0;
+      struct group *gr = getgrnam(config.group_name);
+      if (gr == NULL){
+	//if( errno != 0){
+	  fprintf(stderr, "Invalid group name: %s\n", strerror(errno));
+	  fprintf(stderr, "see `%s -h' for usage\n", argv[0]);
+	  exit(1);
+	//}
+      } else {
+	config.gid = gr->gr_gid;
+      }
+    }
+
   /* File and Dir permissions */
   mode_t mask = umask(0);
   umask(mask); /* restore */