partially done work on total source tree rework, separation of engine context and game context, generalization of renderer for different backends as well as web platform target

src/system/linux/twn_elf.c

@@ -0,0 +1,68 @@
+#include "elf.h"
+
+#include <fcntl.h>
+#include <unistd.h>
+#include <sys/auxv.h>
+#include <elf.h>
+#include <linux/limits.h>
+
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+bool infer_elf_section_bounds(const char *const restrict name,
+                              const char **restrict vm_start,
+                              const char **restrict vm_end)
+{
+    bool result = false;
+    char buf[PATH_MAX];
+    ssize_t l = readlink("/proc/self/exe", buf, PATH_MAX);
+    if (l == -1)
+        goto ERR_CANT_READLINK;
+    buf[l] = 0; /* readlink() doesn't write a terminator */
+
+    int elf = open(buf, O_RDONLY);
+    if (elf == -1)
+        goto ERR_CANT_OPEN_SELF;
+
+    /* elf header */
+    Elf64_Ehdr ehdr;
+    read(elf, &ehdr, sizeof ehdr);
+    if (ehdr.e_ident[EI_MAG0] != ELFMAG0 ||
+            ehdr.e_ident[EI_MAG1] != ELFMAG1 ||
+            ehdr.e_ident[EI_MAG2] != ELFMAG2 ||
+            ehdr.e_ident[EI_MAG3] != ELFMAG3)
+        goto ERR_NOT_ELF;
+
+    /* section header string table */
+    Elf64_Shdr shstrdr;
+    lseek(elf, ehdr.e_shoff + ehdr.e_shstrndx * sizeof (Elf64_Shdr), SEEK_SET);
+    read(elf, &shstrdr, sizeof shstrdr);
+    char *sh = malloc(shstrdr.sh_size);
+    lseek(elf, shstrdr.sh_offset, SEEK_SET);
+    read(elf, sh, shstrdr.sh_size);
+
+    /* walk sections searching for needed name */
+    lseek(elf, ehdr.e_shoff, SEEK_SET);
+    for (size_t s = 0; s < ehdr.e_shnum; ++s) {
+        Elf64_Shdr shdr;
+        read(elf, &shdr, sizeof shdr);
+
+        if (strcmp(&sh[shdr.sh_name], name) == 0) {
+            result = true;
+            *vm_start = getauxval(AT_ENTRY) - ehdr.e_entry + (char *)shdr.sh_addr;
+            *vm_end   = getauxval(AT_ENTRY) - ehdr.e_entry + (char *)shdr.sh_addr + shdr.sh_size;
+            break;
+        }
+    }
+
+    free(sh);
+
+ERR_NOT_ELF:
+    close(elf);
+
+ERR_CANT_OPEN_SELF:
+ERR_CANT_READLINK:
+    return result;
+}

src/system/linux/twn_elf.h

@@ -0,0 +1,10 @@
+#ifndef TWN_ELF_H
+#define TWN_ELF_H
+
+#include <stdbool.h>
+
+bool infer_elf_section_bounds(const char *restrict name,
+                              const char **restrict vm_start,
+                              const char **restrict vm_end);
+
+#endif