From c499eb6896cd803d26da8c719bfac9c03e596c08 Mon Sep 17 00:00:00 2001 From: Nick Alcock Date: Wed, 24 Apr 2019 11:22:03 +0100 Subject: [PATCH] libctf: type copying ctf_add_type() allows you to copy types, and all the types they depend on, from one container to another (writable) container. This lets a program maintaining multiple distinct containers (not in a parent-child relationship) introduce types that depend on types in one container in another writable one, by copying the necessary types. libctf/ * ctf-create.c (enumcmp): New. (enumadd): Likewise. (membcmp): Likewise. (membadd): Likewise. (ctf_add_type): Likewise. --- libctf/ChangeLog | 8 + libctf/ctf-create.c | 485 ++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 493 insertions(+) diff --git a/libctf/ChangeLog b/libctf/ChangeLog index 93209d0b409..c0c98d2f43f 100644 --- a/libctf/ChangeLog +++ b/libctf/ChangeLog @@ -1,3 +1,11 @@ +2019-05-28 Nick Alcock + + * ctf-create.c (enumcmp): New. + (enumadd): Likewise. + (membcmp): Likewise. + (membadd): Likewise. + (ctf_add_type): Likewise. + 2019-05-28 Nick Alcock * ctf-lookup.c (isqualifier): New. diff --git a/libctf/ctf-create.c b/libctf/ctf-create.c index 1035c5ab16d..5409ca4bb4d 100644 --- a/libctf/ctf-create.c +++ b/libctf/ctf-create.c @@ -1446,6 +1446,491 @@ ctf_add_variable (ctf_file_t *fp, const char *name, ctf_id_t ref) return 0; } +static int +enumcmp (const char *name, int value, void *arg) +{ + ctf_bundle_t *ctb = arg; + int bvalue; + + if (ctf_enum_value (ctb->ctb_file, ctb->ctb_type, name, &bvalue) == CTF_ERR) + { + ctf_dprintf ("Conflict due to member %s iteration error.\n", name); + return 1; + } + if (value != bvalue) + { + ctf_dprintf ("Conflict due to value change: %i versus %i\n", + value, bvalue); + return 1; + } + return 0; +} + +static int +enumadd (const char *name, int value, void *arg) +{ + ctf_bundle_t *ctb = arg; + + return (ctf_add_enumerator (ctb->ctb_file, ctb->ctb_type, + name, value) == CTF_ERR); +} + +static int +membcmp (const char *name, ctf_id_t type _libctf_unused_, unsigned long offset, + void *arg) +{ + ctf_bundle_t *ctb = arg; + ctf_membinfo_t ctm; + + if (ctf_member_info (ctb->ctb_file, ctb->ctb_type, name, &ctm) == CTF_ERR) + { + ctf_dprintf ("Conflict due to member %s iteration error.\n", name); + return 1; + } + if (ctm.ctm_offset != offset) + { + ctf_dprintf ("Conflict due to member %s offset change: " + "%lx versus %lx\n", name, ctm.ctm_offset, offset); + return 1; + } + return 0; +} + +static int +membadd (const char *name, ctf_id_t type, unsigned long offset, void *arg) +{ + ctf_bundle_t *ctb = arg; + ctf_dmdef_t *dmd; + char *s = NULL; + + if ((dmd = ctf_alloc (sizeof (ctf_dmdef_t))) == NULL) + return (ctf_set_errno (ctb->ctb_file, EAGAIN)); + + if (name != NULL && (s = ctf_strdup (name)) == NULL) + { + ctf_free (dmd); + return (ctf_set_errno (ctb->ctb_file, EAGAIN)); + } + + /* For now, dmd_type is copied as the src_fp's type; it is reset to an + equivalent dst_fp type by a final loop in ctf_add_type(), below. */ + dmd->dmd_name = s; + dmd->dmd_type = type; + dmd->dmd_offset = offset; + dmd->dmd_value = -1; + + ctf_list_append (&ctb->ctb_dtd->dtd_u.dtu_members, dmd); + + if (s != NULL) + ctb->ctb_file->ctf_dtvstrlen += strlen (s) + 1; + + ctb->ctb_file->ctf_flags |= LCTF_DIRTY; + return 0; +} + +/* The ctf_add_type routine is used to copy a type from a source CTF container + to a dynamic destination container. This routine operates recursively by + following the source type's links and embedded member types. If the + destination container already contains a named type which has the same + attributes, then we succeed and return this type but no changes occur. */ +ctf_id_t +ctf_add_type (ctf_file_t *dst_fp, ctf_file_t *src_fp, ctf_id_t src_type) +{ + ctf_id_t dst_type = CTF_ERR; + uint32_t dst_kind = CTF_K_UNKNOWN; + ctf_id_t tmp; + + const char *name; + uint32_t kind, flag, vlen; + + const ctf_type_t *src_tp, *dst_tp; + ctf_bundle_t src, dst; + ctf_encoding_t src_en, dst_en; + ctf_arinfo_t src_ar, dst_ar; + + ctf_dtdef_t *dtd; + ctf_funcinfo_t ctc; + ssize_t size; + + ctf_hash_t *hp; + + if (!(dst_fp->ctf_flags & LCTF_RDWR)) + return (ctf_set_errno (dst_fp, ECTF_RDONLY)); + + if ((src_tp = ctf_lookup_by_id (&src_fp, src_type)) == NULL) + return (ctf_set_errno (dst_fp, ctf_errno (src_fp))); + + name = ctf_strptr (src_fp, src_tp->ctt_name); + kind = LCTF_INFO_KIND (src_fp, src_tp->ctt_info); + flag = LCTF_INFO_ISROOT (src_fp, src_tp->ctt_info); + vlen = LCTF_INFO_VLEN (src_fp, src_tp->ctt_info); + + switch (kind) + { + case CTF_K_STRUCT: + hp = dst_fp->ctf_structs; + break; + case CTF_K_UNION: + hp = dst_fp->ctf_unions; + break; + case CTF_K_ENUM: + hp = dst_fp->ctf_enums; + break; + default: + hp = dst_fp->ctf_names; + break; + } + + /* If the source type has a name and is a root type (visible at the + top-level scope), lookup the name in the destination container and + verify that it is of the same kind before we do anything else. */ + + if ((flag & CTF_ADD_ROOT) && name[0] != '\0' + && (tmp = ctf_hash_lookup_type (hp, dst_fp, name)) != 0) + { + dst_type = tmp; + dst_kind = ctf_type_kind_unsliced (dst_fp, dst_type); + } + + /* If an identically named dst_type exists, fail with ECTF_CONFLICT + unless dst_type is a forward declaration and src_type is a struct, + union, or enum (i.e. the definition of the previous forward decl). */ + + if (dst_type != CTF_ERR && dst_kind != kind + && (dst_kind != CTF_K_FORWARD + || (kind != CTF_K_ENUM && kind != CTF_K_STRUCT + && kind != CTF_K_UNION))) + { + ctf_dprintf ("Conflict for type %s: kinds differ, new: %i; " + "old (ID %lx): %i\n", name, kind, dst_type, dst_kind); + return (ctf_set_errno (dst_fp, ECTF_CONFLICT)); + } + + /* We take special action for an integer, float, or slice since it is + described not only by its name but also its encoding. For integers, + bit-fields exploit this degeneracy. */ + + if (kind == CTF_K_INTEGER || kind == CTF_K_FLOAT || kind == CTF_K_SLICE) + { + if (ctf_type_encoding (src_fp, src_type, &src_en) != 0) + return (ctf_set_errno (dst_fp, ctf_errno (src_fp))); + + if (dst_type != CTF_ERR) + { + ctf_file_t *fp = dst_fp; + + if ((dst_tp = ctf_lookup_by_id (&fp, dst_type)) == NULL) + return CTF_ERR; + + if (LCTF_INFO_ISROOT (fp, dst_tp->ctt_info) & CTF_ADD_ROOT) + { + /* The type that we found in the hash is also root-visible. If + the two types match then use the existing one; otherwise, + declare a conflict. Note: slices are not certain to match + even if there is no conflict: we must check the contained type + too. */ + + if (ctf_type_encoding (dst_fp, dst_type, &dst_en) != 0) + return CTF_ERR; /* errno set for us. */ + + if (memcmp (&src_en, &dst_en, sizeof (ctf_encoding_t)) == 0) + { + if (kind != CTF_K_SLICE) + return dst_type; + } + else + { + return (ctf_set_errno (dst_fp, ECTF_CONFLICT)); + } + } + else + { + /* We found a non-root-visible type in the hash. We reset + dst_type to ensure that we continue to look for a possible + conflict in the pending list. */ + + dst_type = CTF_ERR; + } + } + } + + /* If the non-empty name was not found in the appropriate hash, search + the list of pending dynamic definitions that are not yet committed. + If a matching name and kind are found, assume this is the type that + we are looking for. This is necessary to permit ctf_add_type() to + operate recursively on entities such as a struct that contains a + pointer member that refers to the same struct type. */ + + if (dst_type == CTF_ERR && name[0] != '\0') + { + for (dtd = ctf_list_prev (&dst_fp->ctf_dtdefs); dtd != NULL + && LCTF_TYPE_TO_INDEX (src_fp, dtd->dtd_type) > dst_fp->ctf_dtoldid; + dtd = ctf_list_prev (dtd)) + { + if (LCTF_INFO_KIND (src_fp, dtd->dtd_data.ctt_info) == kind + && dtd->dtd_name != NULL && strcmp (dtd->dtd_name, name) == 0) + { + int sroot; /* Is the src root-visible? */ + int droot; /* Is the dst root-visible? */ + int match; /* Do the encodings match? */ + + if (kind != CTF_K_INTEGER && kind != CTF_K_FLOAT && kind != CTF_K_SLICE) + return dtd->dtd_type; + + sroot = (flag & CTF_ADD_ROOT); + droot = (LCTF_INFO_ISROOT (dst_fp, + dtd->dtd_data. + ctt_info) & CTF_ADD_ROOT); + + match = (memcmp (&src_en, &dtd->dtd_u.dtu_enc, + sizeof (ctf_encoding_t)) == 0); + + /* If the types share the same encoding then return the id of the + first unless one type is root-visible and the other is not; in + that case the new type must get a new id if a match is never + found. Note: slices are not certain to match even if there is + no conflict: we must check the contained type too. */ + + if (match && sroot == droot) + { + if (kind != CTF_K_SLICE) + return dtd->dtd_type; + } + else if (!match && sroot && droot) + { + return (ctf_set_errno (dst_fp, ECTF_CONFLICT)); + } + } + } + } + + src.ctb_file = src_fp; + src.ctb_type = src_type; + src.ctb_dtd = NULL; + + dst.ctb_file = dst_fp; + dst.ctb_type = dst_type; + dst.ctb_dtd = NULL; + + /* Now perform kind-specific processing. If dst_type is CTF_ERR, then + we add a new type with the same properties as src_type to dst_fp. + If dst_type is not CTF_ERR, then we verify that dst_type has the + same attributes as src_type. We recurse for embedded references. */ + switch (kind) + { + case CTF_K_INTEGER: + /* If we found a match we will have either returned it or declared a + conflict. */ + dst_type = ctf_add_integer (dst_fp, flag, name, &src_en); + break; + + case CTF_K_FLOAT: + /* If we found a match we will have either returned it or declared a + conflict. */ + dst_type = ctf_add_float (dst_fp, flag, name, &src_en); + break; + + case CTF_K_SLICE: + /* We have checked for conflicting encodings: now try to add the + contained type. */ + src_type = ctf_type_reference (src_fp, src_type); + dst_type = ctf_add_type (dst_fp, src_fp, src_type); + + if (src_type == CTF_ERR) + return CTF_ERR; /* errno is set for us. */ + + dst_type = ctf_add_slice (dst_fp, flag, src_type, &src_en); + break; + + case CTF_K_POINTER: + case CTF_K_VOLATILE: + case CTF_K_CONST: + case CTF_K_RESTRICT: + src_type = ctf_type_reference (src_fp, src_type); + src_type = ctf_add_type (dst_fp, src_fp, src_type); + + if (src_type == CTF_ERR) + return CTF_ERR; /* errno is set for us. */ + + dst_type = ctf_add_reftype (dst_fp, flag, src_type, kind); + break; + + case CTF_K_ARRAY: + if (ctf_array_info (src_fp, src_type, &src_ar) == CTF_ERR) + return (ctf_set_errno (dst_fp, ctf_errno (src_fp))); + + src_ar.ctr_contents = + ctf_add_type (dst_fp, src_fp, src_ar.ctr_contents); + src_ar.ctr_index = ctf_add_type (dst_fp, src_fp, src_ar.ctr_index); + src_ar.ctr_nelems = src_ar.ctr_nelems; + + if (src_ar.ctr_contents == CTF_ERR || src_ar.ctr_index == CTF_ERR) + return CTF_ERR; /* errno is set for us. */ + + if (dst_type != CTF_ERR) + { + if (ctf_array_info (dst_fp, dst_type, &dst_ar) != 0) + return CTF_ERR; /* errno is set for us. */ + + if (memcmp (&src_ar, &dst_ar, sizeof (ctf_arinfo_t))) + { + ctf_dprintf ("Conflict for type %s against ID %lx: " + "array info differs, old %lx/%lx/%x; " + "new: %lx/%lx/%x\n", name, dst_type, + src_ar.ctr_contents, src_ar.ctr_index, + src_ar.ctr_nelems, dst_ar.ctr_contents, + dst_ar.ctr_index, dst_ar.ctr_nelems); + return (ctf_set_errno (dst_fp, ECTF_CONFLICT)); + } + } + else + dst_type = ctf_add_array (dst_fp, flag, &src_ar); + break; + + case CTF_K_FUNCTION: + ctc.ctc_return = ctf_add_type (dst_fp, src_fp, src_tp->ctt_type); + ctc.ctc_argc = 0; + ctc.ctc_flags = 0; + + if (ctc.ctc_return == CTF_ERR) + return CTF_ERR; /* errno is set for us. */ + + dst_type = ctf_add_function (dst_fp, flag, &ctc, NULL); + break; + + case CTF_K_STRUCT: + case CTF_K_UNION: + { + ctf_dmdef_t *dmd; + int errs = 0; + + /* Technically to match a struct or union we need to check both + ways (src members vs. dst, dst members vs. src) but we make + this more optimal by only checking src vs. dst and comparing + the total size of the structure (which we must do anyway) + which covers the possibility of dst members not in src. + This optimization can be defeated for unions, but is so + pathological as to render it irrelevant for our purposes. */ + + if (dst_type != CTF_ERR && dst_kind != CTF_K_FORWARD) + { + if (ctf_type_size (src_fp, src_type) != + ctf_type_size (dst_fp, dst_type)) + { + ctf_dprintf ("Conflict for type %s against ID %lx: " + "union size differs, old %li, new %li\n", + name, dst_type, ctf_type_size (src_fp, src_type), + ctf_type_size (dst_fp, dst_type)); + return (ctf_set_errno (dst_fp, ECTF_CONFLICT)); + } + + if (ctf_member_iter (src_fp, src_type, membcmp, &dst)) + { + ctf_dprintf ("Conflict for type %s against ID %lx: " + "members differ, see above\n", name, dst_type); + return (ctf_set_errno (dst_fp, ECTF_CONFLICT)); + } + + break; + } + + /* Unlike the other cases, copying structs and unions is done + manually so as to avoid repeated lookups in ctf_add_member + and to ensure the exact same member offsets as in src_type. */ + + dst_type = ctf_add_generic (dst_fp, flag, name, &dtd); + if (dst_type == CTF_ERR) + return CTF_ERR; /* errno is set for us. */ + + dst.ctb_type = dst_type; + dst.ctb_dtd = dtd; + + if (ctf_member_iter (src_fp, src_type, membadd, &dst) != 0) + errs++; /* Increment errs and fail at bottom of case. */ + + if ((size = ctf_type_size (src_fp, src_type)) > CTF_MAX_SIZE) + { + dtd->dtd_data.ctt_size = CTF_LSIZE_SENT; + dtd->dtd_data.ctt_lsizehi = CTF_SIZE_TO_LSIZE_HI (size); + dtd->dtd_data.ctt_lsizelo = CTF_SIZE_TO_LSIZE_LO (size); + } + else + dtd->dtd_data.ctt_size = (uint32_t) size; + + dtd->dtd_data.ctt_info = CTF_TYPE_INFO (kind, flag, vlen); + + /* Make a final pass through the members changing each dmd_type (a + src_fp type) to an equivalent type in dst_fp. We pass through all + members, leaving any that fail set to CTF_ERR. */ + for (dmd = ctf_list_next (&dtd->dtd_u.dtu_members); + dmd != NULL; dmd = ctf_list_next (dmd)) + { + if ((dmd->dmd_type = ctf_add_type (dst_fp, src_fp, + dmd->dmd_type)) == CTF_ERR) + errs++; + } + + if (errs) + return CTF_ERR; /* errno is set for us. */ + break; + } + + case CTF_K_ENUM: + if (dst_type != CTF_ERR && dst_kind != CTF_K_FORWARD) + { + if (ctf_enum_iter (src_fp, src_type, enumcmp, &dst) + || ctf_enum_iter (dst_fp, dst_type, enumcmp, &src)) + { + ctf_dprintf ("Conflict for enum %s against ID %lx: " + "members differ, see above\n", name, dst_type); + return (ctf_set_errno (dst_fp, ECTF_CONFLICT)); + } + } + else + { + dst_type = ctf_add_enum (dst_fp, flag, name); + if ((dst.ctb_type = dst_type) == CTF_ERR + || ctf_enum_iter (src_fp, src_type, enumadd, &dst)) + return CTF_ERR; /* errno is set for us */ + } + break; + + case CTF_K_FORWARD: + if (dst_type == CTF_ERR) + { + dst_type = ctf_add_forward (dst_fp, flag, + name, CTF_K_STRUCT); /* Assume STRUCT. */ + } + break; + + case CTF_K_TYPEDEF: + src_type = ctf_type_reference (src_fp, src_type); + src_type = ctf_add_type (dst_fp, src_fp, src_type); + + if (src_type == CTF_ERR) + return CTF_ERR; /* errno is set for us. */ + + /* If dst_type is not CTF_ERR at this point, we should check if + ctf_type_reference(dst_fp, dst_type) != src_type and if so fail with + ECTF_CONFLICT. However, this causes problems with bitness typedefs + that vary based on things like if 32-bit then pid_t is int otherwise + long. We therefore omit this check and assume that if the identically + named typedef already exists in dst_fp, it is correct or + equivalent. */ + + if (dst_type == CTF_ERR) + { + dst_type = ctf_add_typedef (dst_fp, flag, name, src_type); + } + break; + + default: + return (ctf_set_errno (dst_fp, ECTF_CORRUPT)); + } + + return dst_type; +} + /* Write the compressed CTF data stream to the specified gzFile descriptor. This is useful for saving the results of dynamic CTF containers. */ int -- 2.30.2