- fix segfaults for linked elfs binaries

PR:		138481
Submitted by:	Luigi Rizzo

4 files changed, 251 insertions, 2 deletions

diff --git a/lang/tcc/Makefile b/lang/tcc/Makefile
index 2d8adbd11a55..48ea5830efaf 100644
--- a/lang/tcc/Makefile
+++ b/lang/tcc/Makefile
@@ -7,6 +7,7 @@
 
 PORTNAME=	tcc
 PORTVERSION=	0.9.25
+PORTREVISION=	1
 CATEGORIES=	lang
 MASTER_SITES=	${MASTER_SITE_SAVANNAH}
 MASTER_SITE_SUBDIR=	tinycc
diff --git a/lang/tcc/files/README.tccelf b/lang/tcc/files/README.tccelf
new file mode 100644
index 000000000000..40a75d8af23a
--- /dev/null
+++ b/lang/tcc/files/README.tccelf
@@ -0,0 +1,43 @@
+
+I think i have managed to solve the problem and produce
+almost valid elf files on FreeBSD. The two patches attached
+should go in ports/tcc/files (patch-libtcc.c replaces
+the existing one with the same name) and bumping PORTREVISION
+should complete the job. I can do the commit myself if the
+maintainer has no time.
+
+The patches address a few problems (trying to explain to the
+best of my knowledge; i am not very familiar with ELF and
+the FreeBSD ELF conventions):
+
+1. ELF file format
+   tcc produces an ELF executable which is good for linux but
+   not for FreeBSD. It misses the PHDR section which is almost
+   mandatory for shared executables, puts in the .dynsym section
+   some relocation info that FreeBSD expects to be in .got,
+   and expect the relocation sections to be contiguous.
+
+   patch-tccelf.c tries to address the above problem using
+   conditional sections (so hopefully can be imported upstream)
+   and also adds the ability to override the name of the dynamic
+   loader through an environment variable (this is important to
+   debug tcc).
+
+2. predefined macros
+
+   patch-libtcc.c adds/fixes some predefined macros when compiling
+   on FreeBSD: these are __FreeBSD__ and the usual set of
+   __i386__ and __unix__ variants.
+   It also sets __INTEL_COMPILER so we can grab the __aligned
+   macro from cdefs.h , otherwise many programs would fail
+
+The resulting elf file is still not 100% correct -- if you strip it,
+the program will not run (presumably there is some dangling reference).
+Other than that, program do seem to run correctly.
+
+I am going to submit the patch upstream to see if the maintainers
+want to integrate it
+
+	cheers
+	luigi
+
diff --git a/lang/tcc/files/patch-libtcc.c b/lang/tcc/files/patch-libtcc.c
index 9c514b3dcfc7..2fd6d59ee674 100644
--- a/lang/tcc/files/patch-libtcc.c
+++ b/lang/tcc/files/patch-libtcc.c
@@ -1,5 +1,6 @@
---- libtcc.c.orig	2009-05-18 16:27:06.000000000 +0200
-+++ libtcc.c	2009-07-03 07:51:05.000000000 +0200
+diff -ubwr ./libtcc.c ../../work.2/tcc-0.9.25/libtcc.c
+--- ./libtcc.c	2009-05-18 16:27:06.000000000 +0200
++++ ../../work.2/tcc-0.9.25/libtcc.c	2009-11-29 02:25:14.000000000 +0100
 @@ -1509,10 +1509,18 @@
  
      if (level == 0) {
@@ -19,3 +20,32 @@
          for(i=1;i<level;i++) {
              /* XXX: check address validity with program info */
              if (fp <= 0x1000)
+@@ -1784,7 +1792,9 @@
+     tcc_define_symbol(s, "__STDC__", NULL);
+     tcc_define_symbol(s, "__STDC_VERSION__", "199901L");
+ #if defined(TCC_TARGET_I386)
+-    tcc_define_symbol(s, "__i386__", NULL);
++    tcc_define_symbol(s, "__i386__", "1");
++    tcc_define_symbol(s, "__i386", "1");
++    tcc_define_symbol(s, "i386", "1");
+ #endif
+ #if defined(TCC_TARGET_X86_64)
+     tcc_define_symbol(s, "__x86_64__", NULL);
+@@ -1802,8 +1812,15 @@
+ #ifdef TCC_TARGET_PE
+     tcc_define_symbol(s, "_WIN32", NULL);
+ #else
+-    tcc_define_symbol(s, "__unix__", NULL);
+-    tcc_define_symbol(s, "__unix", NULL);
++    tcc_define_symbol(s, "__unix__", "1");
++    tcc_define_symbol(s, "__unix", "1");
++    tcc_define_symbol(s, "unix", "1");
++#if defined(__FreeBSD__)
++#define str(s) #s
++    tcc_define_symbol(s, "__FreeBSD__", str( __FreeBSD__));
++    tcc_define_symbol(s, "__INTEL_COMPILER", "1");
++#undef str
++#endif
+ #if defined(__linux)
+     tcc_define_symbol(s, "__linux__", NULL);
+     tcc_define_symbol(s, "__linux", NULL);
diff --git a/lang/tcc/files/patch-tccelf.c b/lang/tcc/files/patch-tccelf.c
new file mode 100644
index 000000000000..a8a1d68c4fc4
--- /dev/null
+++ b/lang/tcc/files/patch-tccelf.c
@@ -0,0 +1,175 @@
+diff -ubwr ./tccelf.c ../../work.2/tcc-0.9.25/tccelf.c
+--- ./tccelf.c	2009-05-18 16:27:06.000000000 +0200
++++ ../../work.2/tcc-0.9.25/tccelf.c	2009-11-29 02:12:36.000000000 +0100
+@@ -1273,7 +1273,7 @@
+ 
+ /* name of ELF interpreter */
+ #if defined __FreeBSD__
+-static char elf_interp[] = "/usr/libexec/ld-elf.so.1";
++static char elf_interp[] = "/libexec/ld-elf.so.1";
+ #elif defined TCC_ARM_EABI
+ static char elf_interp[] = "/lib/ld-linux.so.3";
+ #elif defined(TCC_TARGET_X86_64)
+@@ -1306,6 +1306,31 @@
+     }
+ }
+ 
++#if defined(__FreeBSD__)
++#define	HAVE_PHDR	1
++#define	EXTRA_RELITEMS	14
++
++/* move the relocation value from .dynsym to .got */
++void patch_dynsym_undef(TCCState *s1, Section *s)
++{
++    uint32_t *gotd = (void *)s1->got->data;
++    ElfW(Sym) *sym, *sym_end;
++
++    gotd += 3;	// dummy entries in .got
++    /* relocate symbols in .dynsym */
++    sym_end = (ElfW(Sym) *)(s->data + s->data_offset);
++    for (sym = (ElfW(Sym) *)s->data + 1; sym < sym_end; sym++) {
++	if (sym->st_shndx == SHN_UNDEF) {
++	    *gotd++ = sym->st_value + 6; // XXX 6 is magic ?
++	    sym->st_value = 0;
++	}
++    }
++}
++#else
++#define	HAVE_PHDR	0
++#define	EXTRA_RELITEMS	9
++#endif
++
+ /* output an ELF file */
+ /* XXX: suppress unneeded sections */
+ int elf_output_file(TCCState *s1, const char *filename)
+@@ -1324,6 +1349,7 @@
+     ElfW(Sym) *sym;
+     int type, file_type;
+     unsigned long rel_addr, rel_size;
++    unsigned long bss_addr, bss_size;
+     
+     file_type = s1->output_type;
+     s1->nb_errors = 0;
+@@ -1351,11 +1377,15 @@
+             
+             if (file_type == TCC_OUTPUT_EXE) {
+                 char *ptr;
++		/* allow override the dynamic loader */
++		char *elfint = getenv("LD_SO");
++		if (elfint == NULL)
++		    elfint = elf_interp;
+                 /* add interpreter section only if executable */
+                 interp = new_section(s1, ".interp", SHT_PROGBITS, SHF_ALLOC);
+                 interp->sh_addralign = 1;
+-                ptr = section_ptr_add(interp, sizeof(elf_interp));
+-                strcpy(ptr, elf_interp);
++                ptr = section_ptr_add(interp, 1+strlen(elfint));
++                strcpy(ptr, elfint);
+             }
+         
+             /* add dynamic symbol table */
+@@ -1514,7 +1544,7 @@
+ 
+             /* add necessary space for other entries */
+             saved_dynamic_data_offset = dynamic->data_offset;
+-            dynamic->data_offset += sizeof(ElfW(Dyn)) * 9;
++            dynamic->data_offset += sizeof(ElfW(Dyn)) * EXTRA_RELITEMS;
+         } else {
+             /* still need to build got entries in case of static link */
+             build_got_entries(s1);
+@@ -1543,7 +1573,7 @@
+         break;
+     case TCC_OUTPUT_EXE:
+         if (!s1->static_link)
+-            phnum = 4;
++            phnum = 4 + HAVE_PHDR;
+         else
+             phnum = 2;
+         break;
+@@ -1620,10 +1650,11 @@
+         rel_size = 0;
+         rel_addr = 0;
+ 
++ 	bss_addr = bss_size = 0;
+         /* leave one program header for the program interpreter */
+         ph = &phdr[0];
+         if (interp)
+-            ph++;
++            ph += 1 + HAVE_PHDR;
+ 
+         for(j = 0; j < 2; j++) {
+             ph->p_type = PT_LOAD;
+@@ -1685,9 +1716,20 @@
+                     }
+                     /* update dynamic relocation infos */
+                     if (s->sh_type == SHT_RELX) {
++#if defined(__FreeBSD__)
++                        if (!strcmp(strsec->data + s->sh_name, ".rel.got")) { // rel_size == 0) {
++                            rel_addr = addr;
++			    rel_size += s->sh_size;	// XXX only first rel.
++			}
++                        if (!strcmp(strsec->data + s->sh_name, ".rel.bss")) { // rel_size == 0) {
++                            bss_addr = addr;
++			    bss_size = s->sh_size;	// XXX only first rel.
++			}
++#else
+                         if (rel_size == 0)
+                             rel_addr = addr;
+                         rel_size += s->sh_size;
++#endif
+                     }
+                     addr += s->sh_size;
+                     if (s->sh_type != SHT_NOBITS)
+@@ -1715,6 +1757,21 @@
+         if (interp) {
+             ph = &phdr[0];
+             
++#if defined(__FreeBSD__)
++	    {
++		int len = phnum * sizeof(ElfW(Phdr));
++
++		ph->p_type = PT_PHDR;
++		ph->p_offset = sizeof(ElfW(Ehdr));
++		ph->p_vaddr = interp->sh_addr - len;
++		ph->p_paddr = ph->p_vaddr;
++		ph->p_filesz = ph->p_memsz = len;
++		ph->p_flags = PF_R | PF_X;
++		ph->p_align = 4; // interp->sh_addralign;
++		ph++;
++	    }
++#endif
++
+             ph->p_type = PT_INTERP;
+             ph->p_offset = interp->sh_offset;
+             ph->p_vaddr = interp->sh_addr;
+@@ -1815,10 +1872,19 @@
+             put_dt(dynamic, DT_RELASZ, rel_size);
+             put_dt(dynamic, DT_RELAENT, sizeof(ElfW_Rel));
+ #else
++#if defined(__FreeBSD__)
++            put_dt(dynamic, DT_PLTGOT, s1->got->sh_addr);
++            put_dt(dynamic, DT_PLTRELSZ, rel_size);
++            put_dt(dynamic, DT_JMPREL, rel_addr);
++            put_dt(dynamic, DT_PLTREL, DT_REL);
++            put_dt(dynamic, DT_REL, bss_addr);
++            put_dt(dynamic, DT_RELSZ, bss_size);
++#else
+             put_dt(dynamic, DT_REL, rel_addr);
+             put_dt(dynamic, DT_RELSZ, rel_size);
+             put_dt(dynamic, DT_RELENT, sizeof(ElfW_Rel));
+ #endif
++#endif
+             if (s1->do_debug)
+                 put_dt(dynamic, DT_DEBUG, 0);
+             put_dt(dynamic, DT_NULL, 0);
+@@ -1950,6 +2016,10 @@
+         for(i=1;i<s1->nb_sections;i++) {
+             s = s1->sections[section_order[i]];
+             if (s->sh_type != SHT_NOBITS) {
++#if defined(__FreeBSD__)
++		if (s->sh_type == SHT_DYNSYM)
++		    patch_dynsym_undef(s1, s);
++#endif
+                 while (offset < s->sh_offset) {
+                     fputc(0, f);
+                     offset++;