include, libctf: add cth_parent_strlen CTFv4 header field

The first format difference between v3 and v4 is a cth_parent_strlen header
field.  This field (obviously not present in BTF) is populated from the
string table length of the parent at serialization time (protection against
being serialized before the parent is will be added in a later commit in
this series), and will be used at open time to prohibit opening of dicts
with a different strlen (which would corrupt the child's string table
if it was shared with the parent).

For now, just add the field, populate it at serialization time when linking
(when not linking, no deduplication is done and the correct value remains
unchanged), and dump it.

include/
	* ctf.h (ctf_header) [cth_parent_strlen]: New.

libctf/
	* ctf-dump.c (ctf_dump_header_sizefield): New.
	(ctf_dump_header): Use to dump the cth_parent_strlen.
	* ctf-open.c (upgrade_header_v2): Populate cth_parent_strlen.
	(upgrade_header_v3): Likewise.
	(ctf_flip_header): Flip it.
	(ctf_bufopen): Drop unnecessary initialization.
	* ctf-serialize.c (ctf_serialize): Write it out when linking.

ld/
	* testsuite/ld-ctf/data-func-conflicted-vars.d: Skip the nwe dump output.
	* testsuite/ld-ctf/data-func-conflicted.d: Likewise.

diff --git a/include/ctf.h b/include/ctf.h
index 93926f1c8d4bc97b1a027557ada5b19f8df9d902..c6c74e456200a825d67a8584f7f7f85d978f63a3 100644 (file)
--- a/include/ctf.h
+++ b/include/ctf.h
@@ -190,6 +190,7 @@ typedef struct ctf_header
   uint32_t cth_parlabel;       /* Ref to name of parent lbl uniq'd against.  */
   uint32_t cth_parname;                /* Ref to basename of parent.  */
   uint32_t cth_cuname;         /* Ref to CU name (may be 0).  */
+  uint32_t cth_parent_strlen;  /* cth_strlen of parent (may be 0).  */
   uint32_t cth_lbloff;         /* Offset of label section.  */
   uint32_t cth_objtoff;                /* Offset of object section.  */
   uint32_t cth_funcoff;                /* Offset of function section.  */

diff --git a/ld/testsuite/ld-ctf/data-func-conflicted-vars.d b/ld/testsuite/ld-ctf/data-func-conflicted-vars.d
index f10fa982f70b0ab984ac7ba8e1ab7e052346e12c..e9e798e9205126ae4cc9eb54aae3307b27c380e4 100644 (file)
--- a/ld/testsuite/ld-ctf/data-func-conflicted-vars.d
+++ b/ld/testsuite/ld-ctf/data-func-conflicted-vars.d
@@ -45,6 +45,7 @@ CTF archive member: .*/data-func-1\.c:
 #...
     Parent name: \.ctf
     Compilation unit name: .*/data-func-1\.c
+#...
     Data object section:       .* \(0x[1-9a-f][0-9a-f]* bytes\)
     Type section:      .* \(0xc bytes\)
     String section:    .*

diff --git a/ld/testsuite/ld-ctf/data-func-conflicted.d b/ld/testsuite/ld-ctf/data-func-conflicted.d
index 71f6edb04f79929962b5c747a2bd7d32e8baa34a..e9543d2572ccd0df6bfaac2fb7dffc843d53eeec 100644 (file)
--- a/ld/testsuite/ld-ctf/data-func-conflicted.d
+++ b/ld/testsuite/ld-ctf/data-func-conflicted.d
@@ -40,6 +40,7 @@ CTF archive member: .*/data-func-1\.c:
 #...
     Parent name: \.ctf
     Compilation unit name: .*/data-func-1\.c
+#...
     Data object section:       .* \(0x[1-9a-f][0-9a-f]* bytes\)
     Type section:      .* \(0xc bytes\)
     String section:    .*

diff --git a/libctf/ctf-dump.c b/libctf/ctf-dump.c
index be615deb66a7c53af126fbfc47344efc841c98a6..514fa3d6b7506e1f952971882b98db320a682828 100644 (file)
--- a/libctf/ctf-dump.c
+++ b/libctf/ctf-dump.c
@@ -265,6 +265,24 @@ ctf_dump_header_strfield (ctf_dict_t *fp, ctf_dump_state_t *state,
   return (ctf_set_errno (fp, errno));
 }
 
+/* Dump one size field from the file header into the cds_items.  */
+static int
+ctf_dump_header_sizefield (ctf_dict_t *fp, ctf_dump_state_t *state,
+                         const char *name, uint32_t value)
+{
+  char *str;
+  if (value)
+    {
+      if (asprintf (&str, "%s: %x\n", name, value) < 0)
+       goto err;
+      ctf_dump_append (state, str);
+    }
+  return 0;
+
+ err:
+  return (ctf_set_errno (fp, errno));
+}
+
 /* Dump one section-offset field from the file header into the cds_items.  */
 static int
 ctf_dump_header_sectfield (ctf_dict_t *fp, ctf_dump_state_t *state,
@@ -366,6 +384,9 @@ ctf_dump_header (ctf_dict_t *fp, ctf_dump_state_t *state)
                                hp->cth_cuname) < 0)
     goto err;
 
+  if (ctf_dump_header_sizefield (fp, state, "Parent strlen", hp->cth_parent_strlen) < 0)
+    goto err;
+
   if (ctf_dump_header_sectfield (fp, state, "Label section", hp->cth_lbloff,
                                 hp->cth_objtoff) < 0)
     goto err;

diff --git a/libctf/ctf-open.c b/libctf/ctf-open.c
index 0d2a956f4a8716af2e700fdc93c7cf21e90f12ce..9423ad462bce775b647b724fff0a8b9b30918439 100644 (file)
--- a/libctf/ctf-open.c
+++ b/libctf/ctf-open.c
@@ -412,6 +412,7 @@ upgrade_header_v2 (ctf_header_t *hp)
   hp->cth_funcoff = oldhp->cth_funcoff;
   hp->cth_objtoff = oldhp->cth_objtoff;
   hp->cth_lbloff = oldhp->cth_lbloff;
+  hp->cth_parent_strlen = 0;                   /* Strings start at offset 0.  */
   hp->cth_cuname = 0;                          /* No CU name.  */
 }
 
@@ -430,6 +431,7 @@ upgrade_header_v3 (ctf_header_t *hp)
   hp->cth_funcoff = oldhp->cth_funcoff;
   hp->cth_objtoff = oldhp->cth_objtoff;
   hp->cth_lbloff = oldhp->cth_lbloff;
+  hp->cth_parent_strlen = 0;                   /* Strings start at offset 0.  */
   hp->cth_cuname = oldhp->cth_cuname;
   hp->cth_parname = oldhp->cth_parname;
   hp->cth_parlabel = oldhp->cth_parlabel;
@@ -1115,6 +1117,7 @@ ctf_flip_header (ctf_header_t *cth)
   swap_thing (cth->cth_parlabel);
   swap_thing (cth->cth_parname);
   swap_thing (cth->cth_cuname);
+  swap_thing (cth->cth_parent_strlen);
   swap_thing (cth->cth_objtoff);
   swap_thing (cth->cth_funcoff);
   swap_thing (cth->cth_objtidxoff);
@@ -1446,7 +1449,7 @@ ctf_bufopen (const ctf_sect_t *ctfsect, const ctf_sect_t *symsect,
             const ctf_sect_t *strsect, int *errp)
 {
   const ctf_preamble_t *pp;
-  size_t hdrsz = sizeof (ctf_header_t);
+  size_t hdrsz;
   ctf_header_t *hp;
   ctf_dict_t *fp;
   int foreign_endian = 0;
@@ -1623,6 +1626,18 @@ ctf_bufopen (const ctf_sect_t *ctfsect, const ctf_sect_t *symsect,
       return (ctf_set_open_errno (errp, ECTF_CORRUPT));
     }
 
+  if ((hp->cth_parname != 0 && hp->cth_parname < hp->cth_parent_strlen)
+      || (hp->cth_cuname != 0 && hp->cth_cuname < hp->cth_parent_strlen))
+    {
+      ctf_err_warn (NULL, 0, ECTF_CORRUPT,
+                   _("Parent dict or CU name string offsets "
+                     "(at %x and %x, respectively) are themselves "
+                     "within the parent (upper bound: %x), thus "
+                     "unreachable.\n"), hp->cth_parname, hp->cth_cuname,
+                     hp->cth_parent_strlen);
+      return (ctf_set_open_errno (errp, ECTF_CORRUPT));
+    }
+
   /* Once everything is determined to be valid, attempt to decompress the CTF
      data buffer if it is compressed, or copy it into new storage if it is not
      compressed but needs endian-flipping.  Otherwise we just put the data

diff --git a/libctf/ctf-serialize.c b/libctf/ctf-serialize.c
index 5c7190ec8f3a0005f4c613e80cc9204f67839e78..ebd61457ccb02cb2f0a3d09f4fced06d721503f8 100644 (file)
--- a/libctf/ctf-serialize.c
+++ b/libctf/ctf-serialize.c
@@ -1104,7 +1104,14 @@ ctf_serialize (ctf_dict_t *fp, size_t *bufsiz)
   assert (t == (unsigned char *) buf + sizeof (ctf_header_t) + hdr.cth_stroff);
 
   /* Construct the final string table and fill out all the string refs with the
-     final offsets.  */
+     final offsets.  At link time, before the strtab can be constructed, child
+     dicts also need their cth_parent_strlen header field updated to match the
+     parent's.  (These are always newly-created dicts, so we don't need to worry
+     about the upgraded-from-v3 case, which must always retain a
+     cth_parent_strlen value of 0.)  */
+
+  if ((fp->ctf_flags & LCTF_LINKING) && fp->ctf_parent)
+    fp->ctf_header->cth_parent_strlen = fp->ctf_parent->ctf_str[CTF_STRTAB_0].cts_len;
 
   strtab = ctf_str_write_strtab (fp);
 
@@ -1126,6 +1133,7 @@ ctf_serialize (ctf_dict_t *fp, size_t *bufsiz)
   hdrp->cth_strlen = strtab->cts_len;
   buf_size += hdrp->cth_strlen;
   *bufsiz = buf_size;
+  hdrp->cth_parent_strlen = fp->ctf_header->cth_parent_strlen;
 
   return buf;