From 36f17d24955ce912c79bf587c37de3da2cbe7667 Mon Sep 17 00:00:00 2001
From: Alessandro Strada <alessandro.strada@gmail.com>
Date: Sun, 11 Feb 2024 22:12:21 +0100
Subject: [PATCH] Better command line parsing

---
 lib/Fuse_main.c | 102 +++++++++++++++++++++++++++++++++++-------------
 1 file changed, 74 insertions(+), 28 deletions(-)

diff --git a/lib/Fuse_main.c b/lib/Fuse_main.c
index 3616274..d0c67be 100644
--- a/lib/Fuse_main.c
+++ b/lib/Fuse_main.c
@@ -28,8 +28,8 @@
 #endif
 
 #include <caml/callback.h>
-#include <caml/mlvalues.h>
 
+#include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -40,54 +40,100 @@
 
 char **insert_foreground_option(int argc, char **argv);
 void free_fuse_argv(int n, char **fuse_argv);
+void start_program(int argc, char **argv, char *mountpoint, int foreground);
+void parse_fuse_args(int argc, char **argv, struct fuse_args *args);
+bool is_fuse_arg(char *arg, char *prev);
 
 /* https://v2.ocaml.org/releases/5.1/htmlman/intfc.html#ss:main-c */
 int main(int argc, char **argv) {
-  int c;
-  int foreground = 0;
-  int res;
-  char **fuse_argv = argv;
+  struct fuse_args args = FUSE_ARGS_INIT(0, NULL);
+  char *mountpoint;
+  int foreground;
 
-  opterr = 0;
-  while ((c = getopt(argc, argv, "f")) != -1) {
-    switch (c) {
-    case 'f':
-      foreground = 1;
-      break;
-    default:
-      break;
+  parse_fuse_args(argc, argv, &args);
+  if (fuse_parse_cmdline(&args, &mountpoint, NULL, &foreground) != -1) {
+    start_program(argc, argv, mountpoint, foreground);
+
+    fuse_opt_free_args(&args);
+    return 0;
+  }
+
+  fuse_opt_free_args(&args);
+  return 1;
+}
+
+void parse_fuse_args(int argc, char **argv, struct fuse_args *args) {
+  int i = 1;
+
+  fuse_opt_add_arg(args, argv[0]);
+  while (i < argc) {
+    if (is_fuse_arg(argv[i], argv[i - 1])) {
+      fuse_opt_add_arg(args, argv[i]);
     }
+    ++i;
   }
+}
 
-  /* https://github.com/libfuse/libfuse/blob/d04687923194d906fe5ad82dcd546c9807bf15b6/include/fuse_common.h#L246
-   */
-  if (fuse_daemonize(foreground) == -1) {
-    perror("fuse_daemonize");
-    return 1;
+bool is_fuse_arg(char *arg, char *prev) {
+  if (strcmp(arg, "--help") == 0) {
+    return true;
   }
+  if (strcmp(arg, "--version") == 0) {
+    return true;
+  }
+  if (arg[0] == '-') {
+    switch (arg[1]) {
+    case 'o':
+    case 'h':
+    case 'V':
+    case 'd':
+    case 'f':
+    case 's':
+      return true;
+    }
+  } else {
+    if (prev != NULL && strcmp(prev, "-o") == 0) {
+      return true;
+    } else {
+      if (access(arg, F_OK) == 0) {
+        return true;
+      }
+    }
+  }
+  return false;
+}
+
+void start_program(int argc, char **argv, char *mountpoint, int foreground) {
+  char **fuse_argv = argv;
+
+  if (mountpoint != NULL) {
+    /* https://github.com/libfuse/libfuse/blob/d04687923194d906fe5ad82dcd546c9807bf15b6/include/fuse_common.h#L246
+     */
+    if (fuse_daemonize(foreground) == -1) {
+      perror("fuse_daemonize");
+      exit(1);
+    }
 
-  if (foreground == 0) {
-    fuse_argv = insert_foreground_option(argc, argv);
+    if (!foreground) {
+      fuse_argv = insert_foreground_option(argc, argv);
+    }
   }
 
   caml_main(fuse_argv);
 
-  if (foreground == 0) {
+  if (fuse_argv != argv) {
     free_fuse_argv(argc + 1, fuse_argv);
   }
-
-  return 0;
 }
 
 char **insert_foreground_option(int argc, char **argv) {
-  char *mountpoint = argv[argc - 1];
   char **new_argv = malloc((argc + 2) * sizeof(*new_argv));
 
-  for (int i = 0; i < argc - 1; ++i) {
-    new_argv[i] = strdup(argv[i]);
+  new_argv[0] = strdup(argv[0]);
+  new_argv[1] = strdup("-f");
+  for (int i = 1; i < argc; ++i) {
+    new_argv[i + 1] = strdup(argv[i]);
   }
-  new_argv[argc - 1] = strdup("-f");
-  new_argv[argc] = strdup(mountpoint);
   return new_argv;
 }