Split common headers in header/src files.

13 files changed, 205 insertions, 97 deletions

diff --git a/02_process_init/Makefile b/02_process_init/Makefile
index db04941..0b51903 100644
--- a/02_process_init/Makefile
+++ b/02_process_init/Makefile
@@ -3,14 +3,17 @@
 show: entry
 	./entry 1 2 3 4
 
-entry: entry.S entry.c
-	gcc -o $@         \
-	    -g -O0        \
-	    -Wall -Wextra \
-	    -I ../include \
-	    -nostdlib     \
-	    -static       \
+entry: entry.S entry.c ../lib/libcommon.a
+	gcc -o $@              \
+	    -g -O0             \
+	    -Wall -Wextra      \
+	    -I../lib/include   \
+	    -nostdlib          \
+	    -static            \
 	    $^
 
+../lib/libcommon.a:
+	make -C ../lib
+
 clean:
 	rm -f entry
diff --git a/02_process_init/entry.c b/02_process_init/entry.c
index 37d5fc8..ca24f77 100644
--- a/02_process_init/entry.c
+++ b/02_process_init/entry.c
@@ -2,7 +2,6 @@
 
 #include <auxv.h>
 #include <elf.h>
-#define MAX_PRINTF_LEN 128
 #include <io.h>
 
 #if !defined(__linux__) || !defined(__x86_64__)
diff --git a/include/elf.h b/include/elf.h
deleted file mode 100644
index 7e279fe..0000000
--- a/include/elf.h
+++ /dev/null
@@ -1,26 +0,0 @@
-// Copyright (c) 2020 Johannes Stoelp
-
-#pragma once
-
-#include <bits/stdint-uintn.h>
-#include <stdint.h>
-
-enum eAuxvTag {
-    AT_NULL   =  0, /* ignored */
-    AT_IGNORE =  1, /* ignored */
-    AT_EXECFD =  2, /* val */
-    AT_PHDR   =  3, /* ptr */
-    AT_PHENT  =  4, /* val */
-    AT_PHNUM  =  5, /* val */
-    AT_PAGESZ =  6, /* val */
-    AT_BASE   =  7, /* ptr */
-    AT_FLAGS  =  8, /* val */
-    AT_ENTRY  =  9, /* ptr */
-    AT_NOTELF = 10, /* val */
-    AT_UID    = 11, /* val */
-    AT_EUID   = 12, /* val */
-    AT_GID    = 13, /* val */
-    AT_EGID   = 14, /* val */
-
-    AT_MAX_CNT,
-};
diff --git a/lib/Makefile b/lib/Makefile
new file mode 100644
index 0000000..29c103a
--- /dev/null
+++ b/lib/Makefile
@@ -0,0 +1,25 @@
+# Copyright (c) 2020 Johannes Stoelp
+
+HDR+=include/auxv.h
+HDR+=include/elf.h
+HDR+=include/fmt.h
+HDR+=include/io.h
+HDR+=include/syscall.h
+
+DEP+=src/io.o
+DEP+=src/fmt.o
+
+libcommon.a: $(HDR) $(DEP)
+	ar -crs $@ $(filter %.o, $^)
+
+src/%.o: src/%.c
+	gcc -c -o $@            \
+	    -g -O0              \
+	    -Wall -Wextra       \
+	    -I$(CURDIR)/include \
+	    -nostdlib           \
+	    $<
+
+clean:
+	rm -f $(DEP)
+	rm -f libcommon.a
diff --git a/lib/include/auxv.h b/lib/include/auxv.h
new file mode 100644
index 0000000..42dac38
--- /dev/null
+++ b/lib/include/auxv.h
@@ -0,0 +1,36 @@
+// Copyright (c) 2020 Johannes Stoelp
+
+#pragma once
+
+#include <stdint.h>
+
+/// ----------------
+/// Auxiliary Vector
+/// ----------------
+
+// NOTE: [x86-64] Either AT_EXECFD or AT_PHDR must be supplied by the Kernel.
+
+#define AT_NULL    0  /* [ignored] Mark end of auxiliary vetcor */
+#define AT_IGNORE  1  /* [ignored] */
+#define AT_EXECFD  2  /* [val] File descriptor of user program (in case Linux Kernel didn't mapped) */
+#define AT_PHDR    3  /* [ptr] Address of Phdr of use program (in case Kernel mapped user program) */
+#define AT_PHENT   4  /* [val] Size in bytes of one Phdr entry */
+#define AT_PHNUM   5  /* [val] Number of Phread entries */
+#define AT_PAGESZ  6  /* [val] System page size */
+#define AT_BASE    7  /* [ptr] `base address` interpreter was loaded to */
+#define AT_FLAGS   8  /* [val] */
+#define AT_ENTRY   9  /* [ptr] Entry point of user program */
+#define AT_NOTELF  10 /* [val] >0 if not an ELF file */
+#define AT_UID     11 /* [val] Real user id of process */
+#define AT_EUID    12 /* [val] Effective user id of process */
+#define AT_GID     13 /* [val] Real group id of process */
+#define AT_EGID    14 /* [val] Effective user id of process */
+#define AT_MAX_CNT 15
+
+typedef struct {
+    uint64_t tag;
+    union {
+        uint64_t val;
+        void* ptr;
+    };
+} Auxv64Entry;
diff --git a/lib/include/elf.h b/lib/include/elf.h
new file mode 100644
index 0000000..a0fe6f7
--- /dev/null
+++ b/lib/include/elf.h
@@ -0,0 +1,75 @@
+// Copyright (c) 2020 Johannes Stoelp
+
+#pragma once
+
+#include <stdint.h>
+
+/// --------------
+/// Program Header
+/// --------------
+
+#define PT_NULL    0 /* ignored */
+#define PT_LOAD    1 /* Mark loadable segment (allowed p_memsz > p_filesz). */
+#define PT_DYNAMIC 2 /* Location of .dynamic section */
+#define PT_INTERP  3 /* Location of .interp section */
+#define PT_NOTE    4 /* Location of auxiliary information */
+#define PT_SHLIB   5 /* Reserved, but unspecified semantic */
+#define PT_PHDR    6 /* Location & size of program headers itself */
+
+#define PT_GNU_EH_FRAME 0x6474e550 /* [x86-64] stack unwinding tables */
+#define PT_LOPROC       0x70000000
+#define PT_HIPROC       0x7fffffff
+
+#define PF_X 0x1 /* Phdr flag eXecute flag bitmask */
+#define PF_W 0x2 /* Phdr flag Write flag bitmask */
+#define PF_R 0x4 /* Phdr flag Read flag bitmask */
+
+typedef struct {
+    uint32_t type;    // Segment kind.
+    uint32_t flags;   // Flags describing Segment attributes like R, W, X.
+    uint64_t offset;  // Offset into the file where the Segment starts.
+    uint64_t vaddr;   // Virtual address of first byte of Segment in memory.
+    uint64_t paddr;   // Physical address, ignored in our case.
+    uint64_t filesz;  // Number of bytes of the Segment in the file image.
+    uint64_t memsz;   // Number of bytes of the segement in memory.
+    uint64_t align;
+} Elf64Phdr;
+
+/// ---------------
+/// Dynamic Section
+/// ---------------
+
+#define DT_NULL     0 /* [ignored] Marks end of dynamic section */
+#define DT_NEEDED   1 /* [val] Name of needed library */
+#define DT_PLTRELSZ 2 /* [val] Size in bytes of PLT relocs */
+#define DT_PLTGOT   3 /* [ptr] Processor defined value */
+#define DT_HASH     4 /* [ptr] Address of symbol hash table */
+#define DT_STRTAB   5 /* [ptr] Address of string table */
+#define DT_SYMTAB   6 /* [ptr] Address of symbol table */
+#define DT_RELA     7 /* [ptr] Address of Rela relocs */
+#define DT_RELASZ   8 /* [val] Total size of Rela relocs */
+#define DT_RELAENT  9 /* [val] Size of one Rela reloc */
+#define DT_STRSZ    10 /* [val] Size of string table */
+#define DT_SYMENT   11 /* [val] Size of one symbol table entry */
+#define DT_INIT     12 /* [ptr] Address of init function */
+#define DT_FINI     13 /* [ptr] Address of termination function */
+#define DT_SONAME   14 /* [val] Name of shared object */
+#define DT_RPATH    15 /* [val] Library search path (deprecated) */
+#define DT_SYMBOLIC 16 /* [ignored] Start symbol search here */
+#define DT_REL      17 /* [ptr] Address of Rel relocs */
+#define DT_RELSZ    18 /* [val] Total size of Rel relocs */
+#define DT_RELENT   19 /* [val] Size of one Rel reloc */
+#define DT_PLTREL   20 /* [val] Type of reloc in PLT */
+#define DT_DEBUG    21 /* [ptr] For debugging; unspecified */
+#define DT_TEXTREL  22 /* [ignored] Reloc might modify .text */
+#define DT_JMPREL   23 /* [ptr] Address of PLT relocs */
+#define DT_BIND_NOW 24 /* [ignored] Process relocations of object */
+#define DT_MAX_CNT  25
+
+typedef struct {
+    uint64_t tag;
+    union {
+        uint64_t val;
+        void* ptr;
+    };
+} Elf64Dyn;
diff --git a/lib/include/fmt.h b/lib/include/fmt.h
new file mode 100644
index 0000000..61215bc
--- /dev/null
+++ b/lib/include/fmt.h
@@ -0,0 +1,8 @@
+// Copyright (c) 2020 Johannes Stoelp
+
+#pragma once
+
+#include <stdarg.h>
+
+int vfmt(char* buf, unsigned long len, const char* fmt, va_list ap);
+int fmt(char* buf, unsigned long len, const char* fmt, ...);
diff --git a/lib/include/io.h b/lib/include/io.h
new file mode 100644
index 0000000..5ca78a3
--- /dev/null
+++ b/lib/include/io.h
@@ -0,0 +1,5 @@
+// Copyright (c) 2020 Johannes Stoelp
+
+#pragma once
+
+int pfmt(const char* fmt, ...);
diff --git a/include/syscall.h b/lib/include/syscall.h
index 0508b38..4947155 100644
--- a/include/syscall.h
+++ b/lib/include/syscall.h
@@ -28,7 +28,7 @@
 //    machine specific constraint.
 //    ```c
 //    register long r12 asm ("r12") = 42;
-//    asm("nop" : : "r"(r10));
+//    asm("nop" : : "r"(r12));
 //    ```
 //
 // Reference:
diff --git a/include/fmt.h b/lib/src/fmt.c
index f4be0b1..be1ca3a 100644
--- a/include/fmt.h
+++ b/lib/src/fmt.c
@@ -1,16 +1,40 @@
 // Copyright (c) 2020 Johannes Stoelp
 
-#pragma once
+#include <fmt.h>
 
-#include <stdarg.h>
+static const char* num2dec(char* buf, unsigned long len, unsigned long long num) {
+    char* pbuf = buf + len - 1;
+    *pbuf = '\0';
 
-#define ALLOW_UNUSED __attribute__((unused))
+    if (num == 0) {
+        *(--pbuf) = '0';
+    }
 
-static const char* num2dec(char* buf, unsigned long len, unsigned long long num);
-static const char* num2hex(char* buf, unsigned long len, unsigned long long num);
+    while (num > 0 && pbuf != buf) {
+        char d = (num % 10) + '0';
+        *(--pbuf) = d;
+        num /= 10;
+    }
+    return pbuf;
+}
 
-ALLOW_UNUSED
-static int vfmt(char* buf, unsigned long len, const char* fmt, va_list ap) {
+static const char* num2hex(char* buf, unsigned long len, unsigned long long num) {
+    char* pbuf = buf + len - 1;
+    *pbuf = '\0';
+
+    if (num == 0) {
+        *(--pbuf) = '0';
+    }
+
+    while (num > 0 && pbuf != buf) {
+        char d = (num & 0xf);
+        *(--pbuf) = d + (d > 9 ? 'a' - 10 : '0');
+        num >>= 4;
+    }
+    return pbuf;
+}
+
+int vfmt(char* buf, unsigned long len, const char* fmt, va_list ap) {
     unsigned i = 0;
 
 #define put(c)           \
@@ -84,47 +108,10 @@ static int vfmt(char* buf, unsigned long len, const char* fmt, va_list ap) {
     return i;
 }
 
-ALLOW_UNUSED
-static int fmt(char* buf, unsigned long len, const char* fmt, ...) {
+int fmt(char* buf, unsigned long len, const char* fmt, ...) {
     va_list ap;
     va_start(ap, fmt);
     int ret = vfmt(buf, len, fmt, ap);
     va_end(ap);
     return ret;
 }
-
-/// Internal Helper
-
-ALLOW_UNUSED
-static const char* num2dec(char* buf, unsigned long len, unsigned long long num) {
-    char* pbuf = buf + len - 1;
-    *pbuf = '\0';
-
-    if (num == 0) {
-        *(--pbuf) = '0';
-    }
-
-    while (num > 0 && pbuf != buf) {
-        char d = (num % 10) + '0';
-        *(--pbuf) = d;
-        num /= 10;
-    }
-    return pbuf;
-}
-
-ALLOW_UNUSED
-static const char* num2hex(char* buf, unsigned long len, unsigned long long num) {
-    char* pbuf = buf + len - 1;
-    *pbuf = '\0';
-
-    if (num == 0) {
-        *(--pbuf) = '0';
-    }
-
-    while (num > 0 && pbuf != buf) {
-        char d = (num & 0xf);
-        *(--pbuf) = d + (d > 9 ? 'a' - 10 : '0');
-        num >>= 4;
-    }
-    return pbuf;
-}
diff --git a/include/io.h b/lib/src/io.c
index 4f61cbf..efe938b 100644
--- a/include/io.h
+++ b/lib/src/io.c
@@ -1,30 +1,22 @@
 // Copyright (c) 2020 Johannes Stoelp
 
-#pragma once
-
-#include "fmt.h"
-#include "syscall.h"
+#include <io.h>
+#include <fmt.h>
+#include <syscall.h>
 
 #include <asm/unistd.h>
 
 // `pfmt` uses fixed-size buffer on the stack for formating the message
 // (for simplicity and since we don't impl buffered I/O).
 //
-// Size can be re-configured by defining `MAX_PRINTF_LEN` before including
-// `io.h`.
-//
 // NOTE: This allows to specify a large buffer on the stack, but for
 // the purpose of this study that's fine, we are cautious.
-#if !defined(MAX_PRINTF_LEN)
-#    define MAX_PRINTF_LEN 128
-#elif MAX_PRINTF_LEN > 512
-#    error MAX_PRINTF_LEN is limited by 512!
-#endif
+#define MAX_PRINTF_LEN 128
 
 #define FD_STDOUT 1
 #define FD_STDERR 2
 
-static int pfmt(const char* fmt, ...) {
+int pfmt(const char* fmt, ...) {
     char buf[MAX_PRINTF_LEN];
 
     va_list ap;
diff --git a/test/Makefile b/test/Makefile
index 3e6fd74..398ebc1 100644
--- a/test/Makefile
+++ b/test/Makefile
@@ -3,8 +3,11 @@
 check: build
 	./checker
 
-build: checker.cc
-	g++ -o checker -g -O2 -I ../include -Wall -Wextra $^
+build: checker.cc ../lib/libcommon.a
+	g++ -o checker -g -O2 -I ../lib/include -Wall -Wextra $^
+
+../lib/libcommon.a:
+	make -C ../lib
 
 clean:
 	rm -f checker
diff --git a/test/checker.cc b/test/checker.cc
index d5afa87..2707929 100644
--- a/test/checker.cc
+++ b/test/checker.cc
@@ -2,8 +2,9 @@
 
 #include "test_helper.h"
 
-#include <cstdio>
-#include <fmt.h>
+extern "C" {
+    #include <fmt.h>
+}
 
 void check_dec() {
     char have[16];