/* CTF string table management.
- Copyright (C) 2019 Free Software Foundation, Inc.
+ Copyright (C) 2019-2020 Free Software Foundation, Inc.
This file is part of libctf.
#include <ctf-impl.h>
#include <string.h>
-/* Convert an encoded CTF string name into a pointer to a C string by looking
- up the appropriate string table buffer and then adding the offset. */
+/* Convert an encoded CTF string name into a pointer to a C string, using an
+ explicit internal strtab rather than the fp-based one. */
const char *
-ctf_strraw (ctf_file_t *fp, uint32_t name)
+ctf_strraw_explicit (ctf_file_t *fp, uint32_t name, ctf_strs_t *strtab)
{
ctf_strs_t *ctsp = &fp->ctf_str[CTF_NAME_STID (name)];
+ if ((CTF_NAME_STID (name) == CTF_STRTAB_0) && (strtab != NULL))
+ ctsp = strtab;
+
+ /* If this name is in the external strtab, and there is a synthetic strtab,
+ use it in preference. */
+
+ if (CTF_NAME_STID (name) == CTF_STRTAB_1
+ && fp->ctf_syn_ext_strtab != NULL)
+ return ctf_dynhash_lookup (fp->ctf_syn_ext_strtab,
+ (void *) (uintptr_t) name);
+
+ /* If the name is in the internal strtab, and the offset is beyond the end of
+ the ctsp->cts_len but below the ctf_str_prov_offset, this is a provisional
+ string added by ctf_str_add*() but not yet built into a real strtab: get
+ the value out of the ctf_prov_strtab. */
+
+ if (CTF_NAME_STID (name) == CTF_STRTAB_0
+ && name >= ctsp->cts_len && name < fp->ctf_str_prov_offset)
+ return ctf_dynhash_lookup (fp->ctf_prov_strtab,
+ (void *) (uintptr_t) name);
+
if (ctsp->cts_strs != NULL && CTF_NAME_OFFSET (name) < ctsp->cts_len)
return (ctsp->cts_strs + CTF_NAME_OFFSET (name));
return NULL;
}
+/* Convert an encoded CTF string name into a pointer to a C string by looking
+ up the appropriate string table buffer and then adding the offset. */
+const char *
+ctf_strraw (ctf_file_t *fp, uint32_t name)
+{
+ return ctf_strraw_explicit (fp, name, NULL);
+}
+
/* Return a guaranteed-non-NULL pointer to the string with the given CTF
name. */
const char *
{
next = ctf_list_next (ref);
ctf_list_delete (&atom->csa_refs, ref);
- ctf_free (ref);
+ free (ref);
}
}
ctf_str_atom_t *atom = a;
ctf_str_purge_atom_refs (atom);
- ctf_free (atom);
+ free (atom);
}
/* Create the atoms table. There is always at least one atom in it, the null
ctf_str_create_atoms (ctf_file_t *fp)
{
fp->ctf_str_atoms = ctf_dynhash_create (ctf_hash_string, ctf_hash_eq_string,
- ctf_free, ctf_str_free_atom);
+ free, ctf_str_free_atom);
if (fp->ctf_str_atoms == NULL)
return -ENOMEM;
+ if (!fp->ctf_prov_strtab)
+ fp->ctf_prov_strtab = ctf_dynhash_create (ctf_hash_integer,
+ ctf_hash_eq_integer,
+ NULL, NULL);
+ if (!fp->ctf_prov_strtab)
+ goto oom_prov_strtab;
+
+ errno = 0;
ctf_str_add (fp, "");
+ if (errno == ENOMEM)
+ goto oom_str_add;
+
return 0;
+
+ oom_str_add:
+ ctf_dynhash_destroy (fp->ctf_prov_strtab);
+ fp->ctf_prov_strtab = NULL;
+ oom_prov_strtab:
+ ctf_dynhash_destroy (fp->ctf_str_atoms);
+ fp->ctf_str_atoms = NULL;
+ return -ENOMEM;
}
/* Destroy the atoms table. */
void
ctf_str_free_atoms (ctf_file_t *fp)
{
+ ctf_dynhash_destroy (fp->ctf_prov_strtab);
ctf_dynhash_destroy (fp->ctf_str_atoms);
}
-/* Add a string to the atoms table and return it, or return an existing string
- if present, copying the passed-in string. Returns NULL only when out of
- memory (and do not touch the passed-in string in that case). Possibly
- augment the ref list with the passed-in ref. */
-static const char *
+/* Add a string to the atoms table, copying the passed-in string. Return the
+ atom added. Return NULL only when out of memory (and do not touch the
+ passed-in string in that case). Possibly augment the ref list with the
+ passed-in ref. Possibly add a provisional entry for this string to the
+ provisional strtab. */
+static ctf_str_atom_t *
ctf_str_add_ref_internal (ctf_file_t *fp, const char *str,
- int add_ref, uint32_t *ref)
+ int add_ref, int make_provisional, uint32_t *ref)
{
char *newstr = NULL;
ctf_str_atom_t *atom = NULL;
if (add_ref)
{
- if ((aref = ctf_alloc (sizeof (struct ctf_str_atom_ref))) == NULL)
+ if ((aref = malloc (sizeof (struct ctf_str_atom_ref))) == NULL)
return NULL;
aref->caf_ref = ref;
}
ctf_list_append (&atom->csa_refs, aref);
fp->ctf_str_num_refs++;
}
- return atom->csa_str;
+ return atom;
}
- if ((atom = ctf_alloc (sizeof (struct ctf_str_atom))) == NULL)
+ if ((atom = malloc (sizeof (struct ctf_str_atom))) == NULL)
goto oom;
memset (atom, 0, sizeof (struct ctf_str_atom));
- if ((newstr = ctf_strdup (str)) == NULL)
+ if ((newstr = strdup (str)) == NULL)
goto oom;
if (ctf_dynhash_insert (fp->ctf_str_atoms, newstr, atom) < 0)
atom->csa_str = newstr;
atom->csa_snapshot_id = fp->ctf_snapshots;
+
+ if (make_provisional)
+ {
+ atom->csa_offset = fp->ctf_str_prov_offset;
+
+ if (ctf_dynhash_insert (fp->ctf_prov_strtab, (void *) (uintptr_t)
+ atom->csa_offset, (void *) atom->csa_str) < 0)
+ goto oom;
+
+ fp->ctf_str_prov_offset += strlen (atom->csa_str) + 1;
+ }
+
if (add_ref)
{
ctf_list_append (&atom->csa_refs, aref);
fp->ctf_str_num_refs++;
}
- return newstr;
+ return atom;
oom:
- ctf_free (atom);
- ctf_free (aref);
- ctf_free (newstr);
+ if (newstr)
+ ctf_dynhash_remove (fp->ctf_str_atoms, newstr);
+ free (atom);
+ free (aref);
+ free (newstr);
return NULL;
}
-/* Add a string to the atoms table and return it, without augmenting the ref
- list for this string. */
-const char *
+/* Add a string to the atoms table, without augmenting the ref list for this
+ string: return a 'provisional offset' which can be used to return this string
+ until ctf_str_write_strtab is called, or 0 on failure. (Everywhere the
+ provisional offset is assigned to should be added as a ref using
+ ctf_str_add_ref() as well.) */
+uint32_t
ctf_str_add (ctf_file_t *fp, const char *str)
{
- if (str)
- return ctf_str_add_ref_internal (fp, str, FALSE, 0);
- return NULL;
+ ctf_str_atom_t *atom;
+ if (!str)
+ return 0;
+
+ atom = ctf_str_add_ref_internal (fp, str, FALSE, TRUE, 0);
+ if (!atom)
+ return 0;
+
+ return atom->csa_offset;
+}
+
+/* Like ctf_str_add(), but additionally augment the atom's refs list with the
+ passed-in ref, whether or not the string is already present. There is no
+ attempt to deduplicate the refs list (but duplicates are harmless). */
+uint32_t
+ctf_str_add_ref (ctf_file_t *fp, const char *str, uint32_t *ref)
+{
+ ctf_str_atom_t *atom;
+ if (!str)
+ return 0;
+
+ atom = ctf_str_add_ref_internal (fp, str, TRUE, TRUE, ref);
+ if (!atom)
+ return 0;
+
+ return atom->csa_offset;
+}
+
+/* Add an external strtab reference at OFFSET. Returns zero if the addition
+ failed, nonzero otherwise. */
+int
+ctf_str_add_external (ctf_file_t *fp, const char *str, uint32_t offset)
+{
+ ctf_str_atom_t *atom;
+ if (!str)
+ return 0;
+
+ atom = ctf_str_add_ref_internal (fp, str, FALSE, FALSE, 0);
+ if (!atom)
+ return 0;
+
+ atom->csa_external_offset = CTF_SET_STID (offset, CTF_STRTAB_1);
+ return 1;
+}
+
+/* Remove a single ref. */
+void
+ctf_str_remove_ref (ctf_file_t *fp, const char *str, uint32_t *ref)
+{
+ ctf_str_atom_ref_t *aref, *anext;
+ ctf_str_atom_t *atom = NULL;
+
+ atom = ctf_dynhash_lookup (fp->ctf_str_atoms, str);
+ if (!atom)
+ return;
+
+ for (aref = ctf_list_next (&atom->csa_refs); aref != NULL; aref = anext)
+ {
+ anext = ctf_list_next (aref);
+ if (aref->caf_ref == ref)
+ {
+ ctf_list_delete (&atom->csa_refs, aref);
+ free (aref);
+ }
+ }
}
/* A ctf_dynhash_iter_remove() callback that removes atoms later than a given
ctf_dynhash_iter_remove (fp->ctf_str_atoms, ctf_str_rollback_atom, &id);
}
-/* Like ctf_str_add(), but additionally augment the atom's refs list with the
- passed-in ref, whether or not the string is already present. There is no
- attempt to deduplicate the refs list (but duplicates are harmless). */
-const char *
-ctf_str_add_ref (ctf_file_t *fp, const char *str, uint32_t *ref)
-{
- if (str)
- return ctf_str_add_ref_internal (fp, str, TRUE, ref);
- return NULL;
-}
-
/* An adaptor around ctf_purge_atom_refs. */
static void
ctf_str_purge_one_atom_refs (void *key _libctf_unused_, void *value,
ctf_str_atom_t *atom = (ctf_str_atom_t *) value;
ctf_strtab_write_state_t *s = (ctf_strtab_write_state_t *) arg;
- s->strtab->cts_len += strlen (atom->csa_str) + 1;
- s->strtab_count++;
+ /* We only factor in the length of items that have no offset and have refs:
+ other items are in the external strtab, or will simply not be written out
+ at all. They still contribute to the total count, though, because we still
+ have to sort them. We add in the null string's length explicitly, outside
+ this function, since it is explicitly written out even if it has no refs at
+ all. */
+
+ if (s->nullstr == atom)
+ {
+ s->strtab_count++;
+ return;
+ }
+
+ if (!ctf_list_empty_p (&atom->csa_refs))
+ {
+ if (!atom->csa_external_offset)
+ s->strtab->cts_len += strlen (atom->csa_str) + 1;
+ s->strtab_count++;
+ }
}
/* Populate the sorttab with pointers to the strtab atoms. */
if (s->nullstr == atom)
return;
- s->sorttab[s->i++] = atom;
+ /* Skip atoms with no refs. */
+ if (!ctf_list_empty_p (&atom->csa_refs))
+ s->sorttab[s->i++] = atom;
}
/* Sort the strtab. */
}
/* Write out and return a strtab containing all strings with recorded refs,
- adjusting the refs to refer to the corresponding string. The returned
- strtab may be NULL on error. */
+ adjusting the refs to refer to the corresponding string. The returned strtab
+ may be NULL on error. Also populate the synthetic strtab with mappings from
+ external strtab offsets to names, so we can look them up with ctf_strptr().
+ Only external strtab offsets with references are added. */
ctf_strs_writable_t
ctf_str_write_strtab (ctf_file_t *fp)
{
ctf_strtab_write_state_t s;
ctf_str_atom_t **sorttab;
size_t i;
+ int any_external = 0;
memset (&strtab, 0, sizeof (struct ctf_strs_writable));
memset (&s, 0, sizeof (struct ctf_strtab_write_state));
return strtab;
}
+ s.nullstr = nullstr;
ctf_dynhash_iter (fp->ctf_str_atoms, ctf_str_count_strtab, &s);
+ strtab.cts_len++; /* For the null string. */
ctf_dprintf ("%lu bytes of strings in strtab.\n",
(unsigned long) strtab.cts_len);
/* Sort the strtab. Force the null string to be first. */
sorttab = calloc (s.strtab_count, sizeof (ctf_str_atom_t *));
if (!sorttab)
- return strtab;
+ goto oom;
sorttab[0] = nullstr;
s.i = 1;
s.sorttab = sorttab;
- s.nullstr = nullstr;
ctf_dynhash_iter (fp->ctf_str_atoms, ctf_str_populate_sorttab, &s);
qsort (&sorttab[1], s.strtab_count - 1, sizeof (ctf_str_atom_t *),
ctf_str_sort_strtab);
- if ((strtab.cts_strs = ctf_alloc (strtab.cts_len)) == NULL)
- {
- free (sorttab);
- return strtab;
- }
+ if ((strtab.cts_strs = malloc (strtab.cts_len)) == NULL)
+ goto oom_sorttab;
- /* Update the strtab, and all refs. */
+ if (!fp->ctf_syn_ext_strtab)
+ fp->ctf_syn_ext_strtab = ctf_dynhash_create (ctf_hash_integer,
+ ctf_hash_eq_integer,
+ NULL, NULL);
+ if (!fp->ctf_syn_ext_strtab)
+ goto oom_strtab;
+
+ /* Update all refs: also update the strtab appropriately. */
for (i = 0; i < s.strtab_count; i++)
{
- strcpy (&strtab.cts_strs[cur_stroff], sorttab[i]->csa_str);
- ctf_str_update_refs (sorttab[i], cur_stroff);
- cur_stroff += strlen (sorttab[i]->csa_str) + 1;
+ if (sorttab[i]->csa_external_offset)
+ {
+ /* External strtab entry: populate the synthetic external strtab.
+
+ This is safe because you cannot ctf_rollback to before the point
+ when a ctf_update is done, and the strtab is written at ctf_update
+ time. So any atoms we reference here are sure to stick around
+ until ctf_file_close. */
+
+ any_external = 1;
+ ctf_str_update_refs (sorttab[i], sorttab[i]->csa_external_offset);
+ if (ctf_dynhash_insert (fp->ctf_syn_ext_strtab,
+ (void *) (uintptr_t)
+ sorttab[i]->csa_external_offset,
+ (void *) sorttab[i]->csa_str) < 0)
+ goto oom_strtab;
+ sorttab[i]->csa_offset = sorttab[i]->csa_external_offset;
+ }
+ else
+ {
+ /* Internal strtab entry with refs: actually add to the string
+ table. */
+
+ ctf_str_update_refs (sorttab[i], cur_stroff);
+ sorttab[i]->csa_offset = cur_stroff;
+ strcpy (&strtab.cts_strs[cur_stroff], sorttab[i]->csa_str);
+ cur_stroff += strlen (sorttab[i]->csa_str) + 1;
+ }
}
free (sorttab);
+ if (!any_external)
+ {
+ ctf_dynhash_destroy (fp->ctf_syn_ext_strtab);
+ fp->ctf_syn_ext_strtab = NULL;
+ }
+
+ /* All the provisional strtab entries are now real strtab entries, and
+ ctf_strptr() will find them there. The provisional offset now starts right
+ beyond the new end of the strtab. */
+
+ ctf_dynhash_empty (fp->ctf_prov_strtab);
+ fp->ctf_str_prov_offset = strtab.cts_len + 1;
+ return strtab;
+
+ oom_strtab:
+ free (strtab.cts_strs);
+ strtab.cts_strs = NULL;
+ oom_sorttab:
+ free (sorttab);
+ oom:
return strtab;
}