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-rw-r--r--elf/Makefile14
-rw-r--r--elf/check-textrel.c159
2 files changed, 173 insertions, 0 deletions
diff --git a/elf/Makefile b/elf/Makefile
index 16c947e9b4..5d9dabde9c 100644
--- a/elf/Makefile
+++ b/elf/Makefile
@@ -568,3 +568,17 @@ $(objpfx)tst-array3.out: $(objpfx)tst-array3
--library-path $(rpath-link)$(patsubst %,:%,$(sysdep-library-path)) \
$(objpfx)tst-array3 > $@
cmp $@ tst-array1.exp > /dev/null
+
+
+check-textrel-CFLAGS = -O
+$(objpfx)check-textrel: check-textrel.c
+ $(native-compile)
+
+ifeq (yes,$(build-shared))
+tests: $(objpfx)check-textrel.out
+
+$(objpfx)check-textrel.out: $(objpfx)check-textrel
+ $(dir $<)$(notdir $<) $(common-objpfx)libc.so \
+ $(wildcard $(common-objpfx)/*/lib*.so) > $@
+generated += check-textrel check-textrel.out
+endif
diff --git a/elf/check-textrel.c b/elf/check-textrel.c
new file mode 100644
index 0000000000..43e0206ab8
--- /dev/null
+++ b/elf/check-textrel.c
@@ -0,0 +1,159 @@
+#include <byteswap.h>
+#include <elf.h>
+#include <endian.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+
+#ifdef BITS
+
+# define AB(name) _AB (name, BITS)
+# define _AB(name, bits) __AB (name, bits)
+# define __AB(name, bits) name##bits
+# define E(name) _E (name, BITS)
+# define _E(name, bits) __E (name, bits)
+# define __E(name, bits) Elf##bits##_##name
+# define SWAP(val) \
+ ({ __typeof (val) __res; \
+ if ((ehdr.e_ident[EI_DATA] == ELFDATA2MSB && BYTE_ORDER == LITTLE_ENDIAN \
+ || ehdr.e_ident[EI_DATA] == ELFDATA2LSB && BYTE_ORDER == BIG_ENDIAN)\
+ && sizeof (val) != 1) \
+ { \
+ if (sizeof (val) == 2) \
+ __res = bswap_16 (val); \
+ else if (sizeof (val) == 4) \
+ __res = bswap_32 (val); \
+ else \
+ __res = bswap_64 (val); \
+ } \
+ else \
+ __res = (val); \
+ __res; })
+
+
+static int
+AB(handle_file) (const char *fname, int fd)
+{
+ E(Ehdr) ehdr;
+
+ if (pread (fd, &ehdr, sizeof (ehdr), 0) != sizeof (ehdr))
+ {
+ read_error:
+ printf ("%s: read error: %m\n", fname);
+ return 1;
+ }
+
+ const size_t phnum = SWAP (ehdr.e_phnum);
+ const size_t phentsize = SWAP (ehdr.e_phentsize);
+
+ /* Read the program header. */
+ E(Phdr) *phdr = alloca (phentsize * phnum);
+ if (pread (fd, phdr, phentsize * phnum, SWAP (ehdr.e_phoff))
+ != phentsize * phnum)
+ goto read_error;
+
+ /* Search for the PT_DYNAMIC entry. */
+ size_t cnt;
+ for (cnt = 0; cnt < phnum; ++cnt)
+ if (phdr[cnt].p_type == PT_DYNAMIC)
+ break;
+
+ if (cnt == phnum)
+ {
+ printf ("%s: no DYNAMIC segment found\n", fname);
+ return 1;
+ }
+
+ /* Read the dynamic segment. */
+ size_t pmemsz = SWAP(phdr[cnt].p_memsz);
+ E(Dyn) *dyn = alloca (pmemsz);
+ if (pread (fd, dyn, pmemsz, SWAP(phdr[cnt].p_offset)) != pmemsz)
+ goto read_error;
+
+ /* Search for an DT_TEXTREL entry of DT_FLAGS with the DF_TEXTREL
+ bit set. */
+ for (cnt = 0; (cnt + 1) * sizeof (E(Dyn)) - 1 < pmemsz; ++cnt)
+ {
+ if (dyn[cnt].d_tag == DT_NULL)
+ /* We reached the end. */
+ break;
+
+ if (dyn[cnt].d_tag == DT_TEXTREL
+ || (dyn[cnt].d_tag == DT_FLAGS
+ && (dyn[cnt].d_un.d_val & DF_TEXTREL) != 0))
+ {
+ /* Urgh! The DSO has text relocations. */
+ printf ("%s: text relocations used\n", fname);
+ return 1;
+ }
+ }
+
+ printf ("%s: OK\n", fname);
+
+ return 0;
+}
+
+# undef BITS
+#else
+
+# define BITS 32
+# include "check-textrel.c"
+
+# define BITS 64
+# include "check-textrel.c"
+
+
+static int
+handle_file (const char *fname)
+{
+ int fd = open (fname, O_RDONLY);
+ if (fd == -1)
+ {
+ printf ("cannot open %s: %m\n", fname);
+ return 1;
+ }
+
+ /* Read was is supposed to be the ELF header. Read the initial
+ bytes to determine whether this is a 32 or 64 bit file. */
+ char ident[EI_NIDENT];
+ if (read (fd, ident, EI_NIDENT) != EI_NIDENT)
+ {
+ printf ("%s: read error: %m\n", fname);
+ close (fd);
+ return 1;
+ }
+
+ if (memcmp (&ident[EI_MAG0], ELFMAG, SELFMAG) != 0)
+ {
+ printf ("%s: not an ELF file\n", fname);
+ close (fd);
+ return 1;
+ }
+
+ int result;
+ if (ident[EI_CLASS] == ELFCLASS64)
+ result = handle_file64 (fname, fd);
+ else
+ result = handle_file32 (fname, fd);
+
+ close (fd);
+
+ return result;
+}
+
+
+int
+main (int argc, char *argv[])
+{
+ int cnt;
+ int result = 0;
+
+ for (cnt = 1; cnt < argc; ++cnt)
+ result |= handle_file (argv[cnt]);
+
+ return result;
+}
+#endif