Kernel: Make "relist" able to dynamically resize

6 files changed, 86 insertions, 24 deletions

diff --git a/kernel/fs/vfs.c b/kernel/fs/vfs.c
index 16f9186..9312c2a 100644
--- a/kernel/fs/vfs.c
+++ b/kernel/fs/vfs.c
@@ -18,7 +18,7 @@ vfs_fd_t *get_vfs_fd(int fd, process_t *p) {
   }
 
   vfs_fd_t *r;
-  if (!relist_get(&p->file_descriptors, fd, (void **)&r)) {
+  if (!relist_get(&p->file_descriptors, fd, (void **)&r, NULL)) {
     return NULL;
   }
   return r;
@@ -411,7 +411,8 @@ vfs_vm_object_t *vfs_get_vm_object(int fd, u64 length, u64 offset) {
 
 int vfs_dup2(int org_fd, int new_fd) {
   vfs_fd_t *orig;
-  if (!relist_get(&current_task->file_descriptors, org_fd, (void **)&orig)) {
+  if (!relist_get(&current_task->file_descriptors, org_fd, (void **)&orig,
+                  NULL)) {
     assert(0);
     return -1;
   }
diff --git a/kernel/kmalloc.c b/kernel/kmalloc.c
index 12e8232..ce96d54 100644
--- a/kernel/kmalloc.c
+++ b/kernel/kmalloc.c
@@ -236,6 +236,27 @@ void *kallocarray(size_t nmemb, size_t size) {
   return kreallocarray(NULL, nmemb, size);
 }
 
+void *krecalloc(void *ptr, size_t nelem, size_t elsize) {
+  if ((nelem >= MUL_NO_OVERFLOW || elsize >= MUL_NO_OVERFLOW) && nelem > 0 &&
+      SIZE_MAX / nelem < elsize) {
+    return NULL;
+  }
+  if (!ptr) {
+    return kcalloc(nelem, elsize);
+  }
+  size_t new_size = nelem * elsize;
+  void *rc = int_kmalloc(new_size);
+  if (!rc) {
+    return NULL;
+  }
+  size_t l = get_mem_size(ptr);
+  size_t to_copy = min(l, new_size);
+  memset(rc, 0, new_size);
+  memcpy(rc, ptr, to_copy);
+  kfree(ptr);
+  return rc;
+}
+
 void *kcalloc(size_t nelem, size_t elsize) {
   if ((nelem >= MUL_NO_OVERFLOW || elsize >= MUL_NO_OVERFLOW) && nelem > 0 &&
       SIZE_MAX / nelem < elsize) {
diff --git a/kernel/kmalloc.h b/kernel/kmalloc.h
index 8b9d59d..9ea67d7 100644
--- a/kernel/kmalloc.h
+++ b/kernel/kmalloc.h
@@ -14,5 +14,6 @@ void *krealloc(void *ptr, size_t size);
 void *kreallocarray(void *ptr, size_t nmemb, size_t size);
 void *kallocarray(size_t nmemb, size_t size);
 void *kcalloc(size_t nelem, size_t elsize);
+void *krecalloc(void *ptr, size_t nelem, size_t elsize);
 void kfree(void *p);
 int init_heap(void);
diff --git a/kernel/lib/relist.c b/kernel/lib/relist.c
index 6ad30d2..a2f9ce5 100644
--- a/kernel/lib/relist.c
+++ b/kernel/lib/relist.c
@@ -1,15 +1,18 @@
 #include <assert.h>
 #include <kmalloc.h>
 #include <lib/relist.h>
+#include <math.h>
 
 void relist_init(struct relist *list) {
-  list->bitmap_capacity = 100;
+  list->bitmap_capacity = 1;
   list->bitmap = kcalloc(sizeof(u64), list->bitmap_capacity);
   if (!list->bitmap) {
     goto relist_init_error;
   }
-  list->entries = kallocarray(sizeof(void *), (sizeof(u64) * 8));
+  list->entries =
+      kallocarray(sizeof(void *) * sizeof(u64) * 8, list->bitmap_capacity);
   if (!list->entries) {
+    kfree(list->bitmap);
     goto relist_init_error;
   }
   return;
@@ -28,18 +31,27 @@ void relist_reset(struct relist *list) {
 }
 
 int relist_clone(struct relist *in, struct relist *out) {
-  relist_init(out);
-  for (int i = 0;; i++) {
-    void *output;
-    if (!relist_get(in, i, &output)) {
-      break;
-    }
-    if (!relist_add(out, output, NULL)) {
-      relist_free(out);
-      return 0;
-    }
+  out->bitmap_capacity = in->bitmap_capacity;
+  out->bitmap = kcalloc(sizeof(u64), out->bitmap_capacity);
+  if (!out->bitmap) {
+    goto relist_clone_error;
+  }
+  out->entries =
+      kallocarray(sizeof(void *) * sizeof(u64) * 8, out->bitmap_capacity);
+  if (!out->entries) {
+    kfree(out->bitmap);
+    goto relist_clone_error;
   }
+  memcpy(out->bitmap, in->bitmap, sizeof(u64) * out->bitmap_capacity);
+  memcpy(out->entries, in->entries,
+         sizeof(void *) * sizeof(u64) * 8 * out->bitmap_capacity);
   return 1;
+
+relist_clone_error:
+  out->bitmap_capacity = 0;
+  out->entries = NULL;
+  out->bitmap = NULL;
+  return 0;
 }
 
 static int relist_find_free_entry(struct relist *list, u32 *entry) {
@@ -62,7 +74,26 @@ static int relist_find_free_entry(struct relist *list, u32 *entry) {
 int relist_add(struct relist *list, void *value, u32 *index) {
   u32 entry;
   if (!relist_find_free_entry(list, &entry)) {
-    assert(0);
+    u32 new_capacity = list->bitmap_capacity + 1;
+    u64 *new_allocation = kcalloc(sizeof(u64), new_capacity);
+    if (!new_allocation) {
+      return 0;
+    }
+    void *new_entry = krecalloc(list->entries, sizeof(void *) * sizeof(u64) * 8,
+                                new_capacity);
+    if (!new_entry) {
+      kfree(new_allocation);
+      return 0;
+    }
+    if (list->bitmap) {
+      size_t to_copy = min(list->bitmap_capacity, new_capacity) * sizeof(u64);
+      memcpy(new_allocation, list->bitmap, to_copy);
+      kfree(list->bitmap);
+    }
+    list->bitmap = new_allocation;
+    list->bitmap_capacity = new_capacity;
+    list->entries = new_entry;
+    assert(relist_find_free_entry(list, &entry));
   }
   list->entries[entry] = value;
   if (index) {
@@ -73,7 +104,7 @@ int relist_add(struct relist *list, void *value, u32 *index) {
 }
 
 int relist_remove(struct relist *list, u32 index) {
-  if ((index / 64) > list->bitmap_capacity) {
+  if (index >= list->bitmap_capacity * 64) {
     assert(0);
     return 0;
   }
@@ -87,8 +118,7 @@ int relist_remove(struct relist *list, u32 index) {
 }
 
 int relist_set(struct relist *list, u32 index, void *value) {
-  assert(value);
-  if ((index / 64) > list->bitmap_capacity) {
+  if (index >= list->bitmap_capacity * 64) {
     assert(0);
     return 0;
   }
@@ -98,9 +128,14 @@ int relist_set(struct relist *list, u32 index, void *value) {
   return 1;
 }
 
-int relist_get(const struct relist *list, u32 index, void **out) {
-  if ((index / 64) > list->bitmap_capacity) {
-    assert(0);
+int relist_get(const struct relist *list, u32 index, void **out, int *end) {
+  if (end) {
+    *end = 0;
+  }
+  if (index >= list->bitmap_capacity * 64) {
+    if (end) {
+      *end = 1;
+    }
     return 0;
   }
   int is_used = (list->bitmap[index / 64] & ((u64)1 << (index % 64)));
diff --git a/kernel/lib/relist.h b/kernel/lib/relist.h
index 96625ba..734e5dc 100644
--- a/kernel/lib/relist.h
+++ b/kernel/lib/relist.h
@@ -14,6 +14,6 @@ void relist_free(struct relist *list);
 int relist_clone(struct relist *in, struct relist *out);
 int relist_add(struct relist *list, void *value, u32 *index);
 int relist_set(struct relist *list, u32 index, void *value);
-int relist_get(const struct relist *list, u32 index, void **out);
+int relist_get(const struct relist *list, u32 index, void **out, int *end);
 int relist_remove(struct relist *list, u32 index);
 #endif
diff --git a/kernel/sched/scheduler.c b/kernel/sched/scheduler.c
index 42d4dc7..639dd05 100644
--- a/kernel/sched/scheduler.c
+++ b/kernel/sched/scheduler.c
@@ -127,8 +127,12 @@ process_t *create_process(process_t *p, u32 esp, u32 eip) {
     }
     for (int i = 0;; i++) {
       vfs_fd_t *out;
-      if (!relist_get(&r->file_descriptors, i, (void **)&out)) {
-        break;
+      int empty;
+      if (!relist_get(&r->file_descriptors, i, (void **)&out, &empty)) {
+        if (empty) {
+          break;
+        }
+        continue;
       }
       if (out) {
         out->reference_count++;