Refactored and unit-tested filter_special_opts. Shaved a bunch of yak…

…s on the way.

configure.ac

@@ -28,8 +28,14 @@ fi
 
 AM_CONDITIONAL(BUILD_OS_IS_DARWIN, [test x"$build_os" = darwin])
 
-my_CPPFLAGS="-D_REENTRANT -D_FILE_OFFSET_BITS=64"
-my_CFLAGS="-Wall -fno-common"
+# _XOPEN_SOURCE is >= 500 for pread/pwrite; >= 700 for utimensat.
+# __BSD_VISIBLE is for flock() on FreeBSD. It otherwise gets hidden by _XOPEN_SOURCE.
+# _BSD_SOURCE is for stat() nanosecond precision and lutimes().
+# _DEFAULT_SOURCE is the new non-deprecated version of _BSD_SOURCE.
+# _DARWIN_BETTER_REALPATH fixes MacOS realpath() broken around Catalina (#83).
+my_CPPFLAGS="-D_REENTRANT -D_FILE_OFFSET_BITS=64 -D_XOPEN_SOURCE=700 -D__BSD_VISIBLE=1 -D_BSD_SOURCE -D_DEFAULT_SOURCE -D_DARWIN_BETTER_REALPATH"
+
+my_CFLAGS="-Wall -fno-common -std=c99"
 my_LDFLAGS="-pthread"
 AC_SUBST([my_CPPFLAGS])
 AC_SUBST([my_CFLAGS])

src/Makefile.am

@@ -2,8 +2,8 @@
 
 bin_PROGRAMS = bindfs
 
-noinst_HEADERS = debug.h permchain.h userinfo.h misc.h usermap.h rate_limiter.h
-bindfs_SOURCES = bindfs.c debug.c permchain.c userinfo.c misc.c usermap.c rate_limiter.c
+noinst_HEADERS = debug.h permchain.h userinfo.h arena.h misc.h usermap.h rate_limiter.h
+bindfs_SOURCES = bindfs.c debug.c permchain.c userinfo.c arena.c misc.c usermap.c rate_limiter.c
 
 AM_CPPFLAGS = ${my_CPPFLAGS} ${fuse_CFLAGS} ${fuse3_CFLAGS}
 AM_CFLAGS = ${my_CFLAGS}

src/arena.c

@@ -0,0 +1,50 @@
+#include "arena.h"
+
+struct block {
+    size_t size;
+    size_t used;
+    struct block *next;
+    char data_start[];
+};
+
+static const size_t min_block_room = 16 * 1024 - sizeof(struct block);
+
+static void add_block(struct arena* a, size_t room_wanted)
+{
+    if (room_wanted < min_block_room) {
+        room_wanted = min_block_room;
+    }
+    struct block *new_block = malloc(sizeof(struct block) + room_wanted);
+    new_block->size = room_wanted;
+    new_block->used = 0;
+    new_block->next = a->cur_block;
+    a->cur_block = new_block;
+}
+
+void arena_init(struct arena *a)
+{
+    a->cur_block = NULL;
+}
+
+void* arena_malloc(struct arena *a, size_t amount)
+{
+    struct block* b = a->cur_block;
+    if (b == NULL || b->size - b->used < amount) {
+        add_block(a, amount);
+        b = a->cur_block;
+    }
+    void* result = &b->data_start[b->used];
+    b->used += amount;
+    return result;
+}
+
+void arena_free(struct arena *a)
+{
+    struct block* b = a->cur_block;
+    while (b != NULL) {
+        struct block* next = b->next;
+        free(b);
+        b = next;
+    }
+    a->cur_block = NULL;
+}

src/arena.h

@@ -0,0 +1,15 @@
+#ifndef INC_BINDFS_ARENA_H
+#define INC_BINDFS_ARENA_H
+
+#include <stdlib.h>
+
+struct block;
+struct arena {
+    struct block *cur_block;
+};
+
+void arena_init(struct arena *a);
+void* arena_malloc(struct arena *a, size_t amount);
+void arena_free(struct arena *a);
+
+#endif

src/bindfs.c

@@ -31,20 +31,6 @@
 
 #include <config.h>
 
-/* For >= 500 for pread/pwrite; >= 700 for utimensat */
-#define _XOPEN_SOURCE 700
-
-/* For flock() on FreeBSD. It otherwise gets hidden by _XOPEN_SOURCE  */
-#define __BSD_VISIBLE 1
-
-/* For stat() nanosecond precision and lutimes() */
-#define _BSD_SOURCE
-/* The new non-deprecated version of _BSD_SOURCE */
-#define _DEFAULT_SOURCE
-
-/* Fix MacOS realpath() broken around Catalina (#83) */
-#define _DARWIN_BETTER_REALPATH
-
 #include <stdlib.h>
 #include <stddef.h>
 #include <stdio.h>
@@ -97,6 +83,7 @@
 #include <fuse.h>
 #include <fuse_opt.h>
 
+#include "arena.h"
 #include "debug.h"
 #include "misc.h"
 #include "permchain.h"
@@ -367,6 +354,7 @@ Why? Because some of those options like "nofail"
 are special ones interpreted by systemd in /etc/fstab
 */
 struct fuse_args filter_special_opts(struct fuse_args *args);
+static bool keep_option(const char* opt);
 
 static int is_mirroring_enabled()
 {
@@ -2085,8 +2073,8 @@ static int parse_map_file(UserMap *map, UserMap *reverse_map, char *file, int as
     UsermapStatus status;
 
     // Toggle between UID (passwd) and GID (group)
-    const int (*value_to_id)(const char *username, uid_t *ret);
-    const UsermapStatus (*usermap_add)(UserMap *map, uid_t from, uid_t to);
+    int (*value_to_id)(const char *username, uid_t *ret);
+    UsermapStatus (*usermap_add)(UserMap *map, uid_t from, uid_t to);
     const char *label_name, *label_id;
     if (as_gid) {
         value_to_id = &group_gid;
@@ -2336,11 +2324,27 @@ static void atexit_func()
 
 struct fuse_args filter_special_opts(struct fuse_args *args)
 {
-    bool ignore;
+    struct arena arena;
+    arena_init(&arena);
+    int tmp_argc = args->argc;
+    char **tmp_argv;
+
+    filter_o_opts(&keep_option, args->argc, (const char * const *)args->argv, &tmp_argc, &tmp_argv, &arena);
+
     struct fuse_args new_args = FUSE_ARGS_INIT(0, (void*)0);
+    for (int i = 0; i < tmp_argc; i++) {
+        fuse_opt_add_arg(&new_args, tmp_argv[i]);
+    }
+
+    arena_free(&arena);
+    fuse_opt_free_args(args);
+    return new_args;
+}
 
+static bool keep_option(const char* opt)
+{
     // Copied from "libfuse/util/mount.fuse.c" (fuse-3.10.1)
-    const char *ignore_opts[] = {
+    static const char * const ignored_opts[] = {
         "",
         "user",
         "nofail",
@@ -2352,114 +2356,12 @@ struct fuse_args filter_special_opts(struct fuse_args *args)
         NULL
     };
 
-    for (int i = 0; i < args->argc; i++) {
-        ignore = false;
-
-        /* If current element is exactly "-o" modify/check the following element */
-        if (strcmp(args->argv[i], "-o") == 0 && (i+1) < args->argc) {
-
-            /* remove ignored option from a comma separated list */
-            if (strchr(args->argv[i+1], ',') != NULL) {
-                char *tmpStr = (char*) calloc(strlen(args->argv[i+1]) + 1, sizeof(char));
-                char *ptr = strtok(args->argv[i+1], ",");
-                while (ptr != NULL) {
-                    ignore = false;
-                    for (int j = 0; ignore_opts[j]; j++) {
-                        if (strcmp(ptr, ignore_opts[j]) == 0) {
-                            ignore = true;
-                            break;
-                        }
-                    }
-                    if (!ignore) {
-                        if (strlen(tmpStr) > 0) strcat(tmpStr, ",");
-                        strcat(tmpStr, ptr);
-                    }
-                    ptr = strtok(NULL, ",");
-                }
-                if (strlen(tmpStr) > 0) {
-                    args->argv[i+1] = (char*) calloc(strlen(tmpStr) + 1, sizeof(char));
-                    strcpy(args->argv[i+1], tmpStr);
-                    free(tmpStr);
-                    ignore = false;
-                }
-                else {
-                    ignore = true;
-                    ++i;
-                }
-            }
-
-            /* ignore this and the following element if it has exactly the ignored option */
-            else {
-                for (int j = 0; ignore_opts[j]; j++) {
-                    if (strcmp(args->argv[i+1], ignore_opts[j]) == 0) {
-                        ignore = true;
-                        ++i;
-                        break;
-                    }
-                }
-            }
-        }
-
-        /* else if element starts with "-o" */
-        else if (strncmp(args->argv[i], "-o", 2) == 0) {
-
-            /* remove ignored option from a comma seperated list */
-            if (strchr(args->argv[i], ',') != NULL) {
-                char *tmpStr = (char*) calloc(strlen(args->argv[i]) + 1, sizeof(char));
-                char *tmpStr2 = (char*) calloc(strlen(args->argv[i]) + 1 - 2, sizeof(char));
-                // remove first 2 chars from args->argv[i] and save this to tmpStr2
-                memcpy(tmpStr2, args->argv[i] + 2, strlen(args->argv[i]) - 2);
-                char *ptr = strtok(tmpStr2, ",");
-                while (ptr != NULL) {
-                    ignore = false;
-                    for (int j = 0; ignore_opts[j]; j++) {
-                        if (strcmp(ptr, ignore_opts[j]) == 0) {
-                            ignore = true;
-                            break;
-                        }
-                    }
-                    if (!ignore) {
-                        if (strlen(tmpStr) > 0) strcat(tmpStr, ",");
-                        strcat(tmpStr, ptr);
-                    }
-                    ptr = strtok(NULL, ",");
-                }
-                if (strlen(tmpStr) > 0) {
-                    args->argv[i] = (char*) calloc(2 + strlen(tmpStr) + 1, sizeof(char));
-                    strcat(args->argv[i], "-o");
-                    strcat(args->argv[i], tmpStr);
-                    free(tmpStr);
-                    free(tmpStr2);
-                    ignore = false;
-                }
-                else {
-                    ignore = true;
-                }
-            }
-
-            /* ignore this element if it has exactly the ignored option */
-            else {
-                for (int j = 0; ignore_opts[j]; j++) {
-                    char* tmpStr = (char*) calloc(2 + strlen(ignore_opts[j]) + 1, sizeof(char));
-                    strcat(tmpStr, "-o");
-                    strcat(tmpStr, ignore_opts[j]);
-                    if (strcmp(args->argv[i], tmpStr) == 0) {
-                        ignore = true;
-                        free(tmpStr);
-                        break;
-                    }
-                    free(tmpStr);
-                }
-            }
-        }
-        if (!ignore) {
-            fuse_opt_add_arg(&new_args, strdup(args->argv[i]));
+    for (int i = 0; ignored_opts[i] != NULL; ++i) {
+        if (strcmp(ignored_opts[i], opt) == 0) {
+            return false;
         }
     }
-
-    fuse_opt_free_args(args);
-
-    return new_args;
+    return true;
 }
 
 int main(int argc, char *argv[])