np: symbol: Introduce symbol table + symbol cache

This commit introduces a way to allocate and store symbols as structures
consiting of a name and an address. We also provide a way to cache
lookups to provide faster access.

Signed-off-by: Ian Moffett <ian@osmora.org>

1 files changed, 149 insertions, 0 deletions

diff --git a/src/sys/np/core/np_symbol.c b/src/sys/np/core/np_symbol.c
new file mode 100644
index 0000000..7c9349a
--- /dev/null
+++ b/src/sys/np/core/np_symbol.c
@@ -0,0 +1,149 @@
+/*
+ * Copyright (c) 2025 Ian Marco Moffett and L5 engineers
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the project nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <sys/types.h>
+#include <sys/errno.h>
+#include <sys/queue.h>
+#include <sys/syslog.h>
+#include <lib/ptrbox.h>
+#include <os/np.h>
+#include <np/symbol.h>
+#include <string.h>
+
+#define pr_trace(fmt, ...) printf("pirho.sym: " fmt, ##__VA_ARGS__)
+#define pr_error(fmt, ...) printf("pirho.sym: error: " fmt, ##__VA_ARGS__)
+
+/*
+ * Cache a symbol so that future lookups will
+ * be faster
+ *
+ * @slp: Symbol list
+ * @s: Symbol to cache
+ */
+static void
+symbol_cache(struct symlist *slp, struct symbol *s)
+{
+    if (slp == NULL || s == NULL) {
+        return;
+    }
+
+    /* Wrap if needed */
+    if (slp->cache_i >= SYMCACHE_LEN) {
+        slp->cache_i = 0;
+    }
+
+    slp->cache[slp->cache_i++] = s;
+}
+
+int
+symbol_lookup(struct symlist *slp, char *name, struct symbol **res_p)
+{
+    struct symbol *sym = NULL;
+
+    if (slp == NULL || name == NULL) {
+        return -EINVAL;
+    }
+
+    if (res_p == NULL) {
+        return -EINVAL;
+    }
+
+    /* Is what we are looking for in the cache? */
+    for (uint16_t i = 0; i < slp->cache_i; ++i) {
+        sym = slp->cache[i];
+        if (strcmp(sym->name, name) == 0) {
+            *res_p = sym;
+            return 0;
+        }
+    }
+
+    TAILQ_FOREACH(sym, &slp->symq, link) {
+        if (sym == NULL)
+            continue;
+        if (sym->name == NULL)
+            continue;
+
+        if (strcmp(sym->name, name) == 0) {
+            symbol_cache(slp, sym);
+            break;
+        }
+    }
+
+    *res_p = sym;
+    return (sym == NULL) ? -1 : 0;
+}
+
+struct symbol *
+symbol_alloc(struct symlist *slp, char *name, void *addr)
+{
+    struct symbol *sym;
+    struct np_work *work;
+
+    if (slp == NULL || name == NULL) {
+        return NULL;
+    }
+
+    if (addr == NULL) {
+        return NULL;
+    }
+
+    /* Grab the work for this symbol list */
+    if ((work = slp->work) == NULL) {
+        pr_error("bad work pointer");
+        return NULL;
+    }
+
+    sym = ptrbox_alloc(sizeof(*sym), work->work_mem);
+    if (sym == NULL) {
+        pr_error("could not allocated symbol");
+        return NULL;
+    }
+
+    /* Initialize the symbol */
+    sym->name = ptrbox_strdup(name, work->work_mem);
+    sym->addr = addr;
+
+    TAILQ_INSERT_TAIL(&slp->symq, sym, link);
+    ++slp->nsym;
+    return sym;
+}
+
+int
+symlist_init(struct np_work *work, struct symlist *symlist)
+{
+    if (symlist == NULL) {
+        return -EINVAL;
+    }
+
+    TAILQ_INIT(&symlist->symq);
+    symlist->nsym = 0;
+    symlist->cache_i = 0;
+    symlist->work = work;
+    return 0;
+}