add static link

cmd.py

@@ -135,41 +135,77 @@ def build(key):
     make_build_directory()
     gcc_map = {
         KEY_MACHINE : [
-            "/usr/bin/gcc-7", 
-            "-Wall", "-g", "-O0", "-Werror", "-std=gnu99", "-Wno-unused-function",
-            "-I", "./src",
-            "./src/tests/test_machine.c",
-            "./src/common/print.c",
-            "./src/common/convert.c",
-            "./src/common/cleanup.c",
-            "./src/datastruct/trie.c",
-            "./src/datastruct/array.c",
-            "./src/hardware/cpu/isa.c",
-            "./src/hardware/cpu/mmu.c",
-            "./src/hardware/memory/dram.c",
-            "-o", EXE_BIN_MACHINE],
+                [
+                    "/usr/bin/gcc-7", 
+                    "-Wall", "-g", "-O0", "-Werror", "-std=gnu99", "-Wno-unused-function",
+                    "-I", "./src",
+                    "./src/tests/test_machine.c",
+                    "./src/common/print.c",
+                    "./src/common/convert.c",
+                    "./src/common/cleanup.c",
+                    "./src/datastruct/trie.c",
+                    "./src/datastruct/array.c",
+                    "./src/hardware/cpu/isa.c",
+                    "./src/hardware/cpu/mmu.c",
+                    "./src/hardware/memory/dram.c",
+                    "-o", EXE_BIN_MACHINE
+                ]
+            ],
         KEY_LINKER : [
-            "/usr/bin/gcc-7", 
-            "-Wall", "-g", "-O0", "-Werror", "-std=gnu99", "-Wno-unused-function",
-            "-I", "./src",
-            "./src/tests/test_elf.c",
-            "./src/common/print.c",
-            "./src/common/convert.c",
-            "./src/common/tagmalloc.c",
-            "./src/common/cleanup.c",
-            "./src/datastruct/array.c",
-            "./src/datastruct/hashtable.c",
-            "./src/datastruct/linkedlist.c",
-            "./src/linker/parseElf.c",
-            "./src/linker/staticlink.c",
-            "-o", EXE_BIN_LINKER
-        ]
+                [
+                    "/usr/bin/gcc-7", 
+                    "-Wall", "-g", "-O0", "-Werror", "-std=gnu99", "-Wno-unused-function",
+                    "-I", "./src",
+                    "./src/tests/test_elf.c",
+                    "./src/common/print.c",
+                    "./src/common/convert.c",
+                    "./src/common/tagmalloc.c",
+                    "./src/common/cleanup.c",
+                    "./src/datastruct/array.c",
+                    "./src/datastruct/hashtable.c",
+                    "./src/datastruct/linkedlist.c",
+                    "./src/linker/parseElf.c",
+                    "./src/linker/staticlink.c",
+                    "-o", EXE_BIN_LINKER
+                ],
+                [
+                    "/usr/bin/gcc-7", 
+                    "-Wall", "-g", "-O0", "-Werror", "-std=gnu99", "-Wno-unused-function",
+                    "-I", "./src",
+                    "-shared", "-fPIC",
+                    "./src/common/print.c",
+                    "./src/common/convert.c",
+                    "./src/common/tagmalloc.c",
+                    "./src/common/cleanup.c",
+                    "./src/datastruct/array.c",
+                    "./src/datastruct/hashtable.c",
+                    "./src/datastruct/linkedlist.c",
+                    "./src/linker/parseElf.c",
+                    "./src/linker/staticlink.c",
+                    "-o", "./bin/staticlink.so"
+                ],
+                [
+                    "/usr/bin/gcc-7", 
+                    "-Wall", "-g", "-O0", "-Werror", "-std=gnu99", "-Wno-unused-function",
+                    "-I", "./src",
+                    "./src/common/print.c",
+                    "./src/common/convert.c",
+                    "./src/common/tagmalloc.c",
+                    "./src/common/cleanup.c",
+                    "./src/datastruct/array.c",
+                    "./src/datastruct/hashtable.c",
+                    "./src/datastruct/linkedlist.c",
+                    "./src/linker/linker.c", 
+                    "-ldl", "-o", "./bin/link"
+                ],
+            ]
     }
 
     if not key in gcc_map:
         print("input the correct build key:", gcc_map.keys())
         exit()
-    subprocess.run(gcc_map[key])
+    for command in gcc_map[key]:
+        subprocess.run(command)
 
 def run(key):
     assert(os.path.isdir("./bin/"))

src/linker/linker.c

@@ -0,0 +1,106 @@
+/* BCST - Introduction to Computer Systems
+ * Author:      [email protected]
+ * Github:      https://github.com/yangminz/bcst_csapp
+ * Bilibili:    https://space.bilibili.com/4564101
+ * Zhihu:       https://www.zhihu.com/people/zhao-yang-min
+ * This project (code repository and videos) is exclusively owned by yangminz 
+ * and shall not be used for commercial and profitting purpose 
+ * without yangminz's permission.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <assert.h>
+#include <dlfcn.h>
+#include <headers/linker.h>
+#include <headers/common.h>
+
+const char *EXECUTABLE_DIRECTORY = "./files/exe";
+
+// linker front end
+int main(int argc, char **argv)
+{
+    char *elf_fn[64];
+    char *eof_fn;
+    int elf_num = 0;
+
+    // parse the arguments
+    int eof_flag = 0;
+    for (int i = 1; i < argc; ++ i)
+    {
+        char *str = argv[i];
+        if (strcmp(str, "-h") == 0 || strcmp(str, "--help") == 0)
+        {
+            printf("./bin/link <ELF file> ... <ELF file> -o <EOF file>\n");
+            exit(0);
+        }
+        else if (strcmp(argv[i], "-o") == 0)
+        {
+            eof_flag = 1;
+            continue;
+        }
+
+        if (eof_flag == 0)
+        {
+            // elf files
+            elf_fn[elf_num] = str;
+            elf_num ++;
+        }
+        else 
+        {
+            // eof file
+            eof_fn = str;
+        }
+    }
+
+    // parsed the arguments
+
+    // dynamically loading the shared library
+    void *linklib = dlopen("./bin/staticLinker.so", RTLD_LAZY);
+    if (linklib == NULL)
+    {
+        printf("%s\n", dlerror());
+        exit(1);
+    }
+
+    // functions from shared library
+    void (*link_elf)(elf_t **, int, elf_t *);
+    void (*write_eof)(const char *, elf_t *);
+    void (*parse_elf)(const char *, elf_t *);
+    link_elf = dlsym(linklib, "link_elf");
+    write_eof = dlsym(linklib, "write_eof");
+    parse_elf = dlsym(linklib, "parse_elf");
+
+    // do front end logic
+
+    printf("we are DYNAMICALLY LINKING ./bin/linker.so to do STATIC linking:\nlinking ");
+    elf_t **srcs = malloc(elf_num * sizeof(elf_t *));
+    for (int i = 0; i < elf_num; ++ i)
+    {
+        char elf_fullpath[100];
+        sprintf(elf_fullpath, "%s/%s.elf.txt", EXECUTABLE_DIRECTORY, elf_fn[i]);
+        printf("%s ", elf_fullpath);
+
+        srcs[i] = malloc(sizeof(elf_t));
+        parse_elf(elf_fullpath, srcs[i]);
+    }
+
+    elf_t linked;
+    link_elf(srcs, elf_num, &linked);
+
+    char eof_fullpath[100];
+    sprintf(eof_fullpath, "%s/%s.eof.txt", EXECUTABLE_DIRECTORY, eof_fn);
+    printf("into %s\n", eof_fullpath);
+
+    write_eof(eof_fullpath, &linked);
+
+    // releaes elf heap
+    for (int i = 0; i < elf_num; ++ i)
+    {
+        free(srcs[i]);        
+    }
+    free(srcs);
+
+    return 0;
+}

src/linker/parseElf.c

@@ -410,5 +410,9 @@ void free_elf(elf_t *elf)
 {
     assert(elf != NULL);
 
-    tag_sweep("parse_elf");
+    tag_free(elf->sht);
+    tag_free(elf->symt);
+    tag_free(elf->reltext);
+    tag_free(elf->reldata);
+    tag_free(elf);
 }

src/linker/staticlink.c

@@ -753,6 +753,12 @@ static void relocation_processing(elf_t **srcs, int num_srcs, elf_t *dst,
 
 // relocating handlers
 
+static uint64_t get_symbol_runtime_address(elf_t *dst, st_entry_t *sym)
+{
+    // TODO: get the run-time address of symbol
+    return 0;
+}
+
 static void R_X86_64_32_handler(elf_t *dst, sh_entry_t *sh,
     int row_referencing, int col_referencing, int addend,
     st_entry_t *sym_referenced)

src/tests/test_elf.c

@@ -32,5 +32,7 @@ int main()
     free_elf(&src[1]);
     free_elf(&dst);
 
+    finally_cleanup();
+
     return 0;
 }