Thread: [Elftoolchain-developers] [patch] experiment of porting libelf to Debian

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Hi,

I've been trying to port libelf to Debian today, and I managed
make it basically working. There are some issues unclear to me:

(I attached a patch below)

1. elf header files

I found that there are two versions of ELF header files which contain
ELF structures and other definitions. One is provided by GNU libc,
the other one is linux/elf.h(includes asm/elf.h, etc, provided by kernel? ).
I noticed that the one provided by GNU libc has more definitions thus
maybe better for us to use. But asm/elf.h provides arch-dependent defines.

So, in the patch I included asm/elf.h in _libelf_config.h to get
arch-dependent defines (ELF_CLASS, ELF_ARCH, ELF_DATA), and included
elf.h(GNU libc) in libelf.h.

2. strlcat/strlcpy

These two functions are very convenient but unfortunately not inside
GNU libc. I guess there are two solutions for this:

a) Use portable strncpy/strncat, as a result, the code will become
   less elegant.
b) define strlcpy/strlcat.

In the patch I chose b), I added a file called libelf_util.c which
defines these two function. (stolen from FreeBSD libc)

3. STAILQ

Should we just add missing STAILQ defines like we did for NetBSD?

4. pmake compatibility

a) Seems that header files (gelf.h, libelf.h) can not be installed.
After I typed "pmake install", libraries and manual pages got installed,
but not header files.

b) GNU and BSD tsort are probably incompatibible, you can see some
tsort warnings during compiling, but I don't know if that affects the
resulting files.



The patch:

diff -urN elftoolchain/projects/libelf/trunk/_libelf_config.h libelf/_libelf_config.h

--- elftoolchain/projects/libelf/trunk/_libelf_config.h	2008-07-31 12:53:48.000000000 +0200
+++ libelf/_libelf_config.h	2008-07-31 17:37:44.000000000 +0200
@@ -135,6 +135,92 @@
 
 #endif	/* __NetBSD__ */
 
+#ifdef __linux__
+
+#include <asm/elf.h>
+
+#define	LIBELF_CONFIG_ADDR	1
+#define	LIBELF_CONFIG_BYTE	1
+#define	LIBELF_CONFIG_DYN	1
+#define	LIBELF_CONFIG_EHDR	1
+#define	LIBELF_CONFIG_HALF	1
+#define	LIBELF_CONFIG_NOTE	1
+#define	LIBELF_CONFIG_OFF	1
+#define	LIBELF_CONFIG_PHDR	1
+#define	LIBELF_CONFIG_REL	1
+#define	LIBELF_CONFIG_RELA	1
+#define	LIBELF_CONFIG_SHDR	1
+#define	LIBELF_CONFIG_SWORD	1
+#define	LIBELF_CONFIG_SYM	1
+#define	LIBELF_CONFIG_WORD	1
+
+#define	LIBELF_CONFIG_SXWORD	1
+#define	LIBELF_CONFIG_XWORD	1
+
+#define	LIBELF_CONFIG_MOVEP	1
+
+#define	LIBELF_CONFIG_VDEF	1
+#define	LIBELF_CONFIG_VNEED	1
+
+#define	LIBELF_VCSID(ID)
+
+#ifndef	STAILQ_EMPTY
+#define STAILQ_EMPTY(head)      ((head)->stqh_first == NULL)
+#endif
+
+#ifndef	STAILQ_FIRST
+#define STAILQ_FIRST(head)      ((head)->stqh_first)
+#endif
+
+#ifndef	STAILQ_FOREACH
+#define STAILQ_FOREACH(var, head, field)                                \
+        for((var) = STAILQ_FIRST((head));                               \
+           (var);                                                       \
+           (var) = STAILQ_NEXT((var), field))
+#endif
+
+#ifndef	SLIST_FOREACH_SAFE
+#define STAILQ_FOREACH_SAFE(var, head, field, tvar)            \
+       for ((var) = STAILQ_FIRST((head));                      \
+            (var) && ((tvar) = STAILQ_NEXT((var), field), 1);  \
+            (var) = (tvar))
+#endif
+
+#ifndef	STAILQ_INIT
+#define STAILQ_INIT(head) do {                                          \
+        STAILQ_FIRST((head)) = NULL;                                    \
+        (head)->stqh_last = &STAILQ_FIRST((head));                      \
+} while (0)
+#endif
+
+#ifndef	STAILQ_INSERT_TAIL
+#define STAILQ_INSERT_TAIL(head, elm, field) do {                       \
+        STAILQ_NEXT((elm), field) = NULL;                               \
+        *(head)->stqh_last = (elm);                                     \
+        (head)->stqh_last = &STAILQ_NEXT((elm), field);                 \
+} while (0)
+#endif
+
+#ifndef	STAILQ_LAST
+#define STAILQ_LAST(head, type, field)                                  \
+        (STAILQ_EMPTY((head)) ?                                         \
+                NULL :                                                  \
+                ((struct type *)(void *)                                \
+                ((char *)((head)->stqh_last) - offsetof(struct type, field))))
+#endif
+
+#define	LIBELF_ARCH		ELF_ARCH
+#define	LIBELF_BYTEORDER	ELF_DATA
+#define	LIBELF_CLASS		ELF_CLASS
+
+#if	ELF_CLASS == ELFCLASS32
+#define	Elf_Note		Elf32_Nhdr
+#else
+#define	Elf_Note		Elf64_Nhdr
+#endif
+
+#endif	/* __linux__ */
+
 /*
  * Symbols that are sometimes missing in system headers.
  */
diff -urN elftoolchain/projects/libelf/trunk/libelf.h libelf/libelf.h
--- elftoolchain/projects/libelf/trunk/libelf.h	2008-07-31 12:53:48.000000000 +0200
+++ libelf/libelf.h	2008-07-31 17:34:29.000000000 +0200
@@ -38,6 +38,8 @@
 #elif defined(__NetBSD__)
 #include <sys/exec_elf.h>
 #elif defined(__linux__)
+#include <elf.h>
+#include <stdint.h>
 #endif
 
 /* Library private data structures */
diff -urN elftoolchain/projects/libelf/trunk/libelf_util.c libelf/libelf_util.c
--- elftoolchain/projects/libelf/trunk/libelf_util.c	1970-01-01 01:00:00.000000000 +0100
+++ libelf/libelf_util.c	2008-07-31 17:14:37.000000000 +0200
@@ -0,0 +1,65 @@
+#ifdef	__linux__
+
+#include <string.h>
+
+size_t
+strlcat(dst, src, siz)
+        char *dst;
+        const char *src;
+        size_t siz;
+{
+        char *d = dst;
+        const char *s = src;
+        size_t n = siz;
+        size_t dlen;
+
+        /* Find the end of dst and adjust bytes left but don't go past end */
+        while (n-- != 0 && *d != '\0')
+                d++;
+        dlen = d - dst;
+        n = siz - dlen;
+
+        if (n == 0)
+                return(dlen + strlen(s));
+        while (*s != '\0') {
+                if (n != 1) {
+                        *d++ = *s;
+                        n--;
+                }
+                s++;
+        }
+        *d = '\0';
+
+        return(dlen + (s - src));       /* count does not include NUL */
+}
+
+size_t
+strlcpy(dst, src, siz)
+        char *dst;
+        const char *src;
+        size_t siz;
+{
+        char *d = dst;
+        const char *s = src;
+        size_t n = siz;
+
+        /* Copy as many bytes as will fit */
+        if (n != 0 && --n != 0) {
+                do {
+                        if ((*d++ = *s++) == 0)
+                                break;
+                } while (--n != 0);
+        }
+
+        /* Not enough room in dst, add NUL and traverse rest of src */
+        if (n == 0) {
+                if (siz != 0)
+                        *d = '\0';              /* NUL-terminate dst */
+                while (*s++)
+                        ;
+        }
+
+        return(s - src - 1);    /* count does not include NUL */
+}
+
+#endif
diff -urN elftoolchain/projects/libelf/trunk/Makefile libelf/Makefile
--- elftoolchain/projects/libelf/trunk/Makefile	2008-07-31 12:53:48.000000000 +0200
+++ libelf/Makefile	2008-07-31 17:14:57.000000000 +0200
@@ -50,6 +50,7 @@
 	libelf_extended.c					\
 	libelf_phdr.c						\
 	libelf_shdr.c						\
+	libelf_util.c						\
 	libelf_xlate.c						\
 	${GENSRCS}
 INCS=	libelf.h gelf.h




Thread: [Elftoolchain-developers] [patch] experiment of porting libelf to Debian

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