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Remove cc_file.c global lookup table
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The FILE ccache type maintains a global reference-counted table of
handles, which is perhaps an imperfect workaround for POSIX
per-process file locks.  Remove this table, since we plan to maintain
read fds in cursors and use O_APPEND writes to render locking less
important.
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@greghudson
greghudson committed Nov 3, 2014
1 parent ec3a2e9 commit 21c6d59
Showing 1 changed file with 34 additions and 122 deletions.
156 changes: 34 additions & 122 deletions src/lib/krb5/ccache/cc_file.c
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Original file line number Diff line number Diff line change
Expand Up @@ -163,14 +163,7 @@ fcc_lseek(fcc_data *data, off_t offset, int whence)
return lseek(data->fd, offset, whence);
}

struct fcc_set {
struct fcc_set *next;
fcc_data *data;
unsigned int refcount;
};

k5_cc_mutex krb5int_cc_file_mutex = K5_CC_MUTEX_PARTIAL_INITIALIZER;
static struct fcc_set *fccs = NULL;

/* Iterator over file caches. */
struct krb5_fcc_ptcursor_data {
Expand Down Expand Up @@ -769,47 +762,27 @@ fcc_initialize(krb5_context context, krb5_ccache id, krb5_principal princ)
return ret;
}

/* Drop the ref count. If it hits zero, remove the entry from the fcc_set list
* and free it. */
static krb5_error_code dereference(krb5_context context, fcc_data *data)
/* Release an fcc_data object. */
static void
free_fccdata(krb5_context context, fcc_data *data)
{
struct fcc_set **fccsp, *temp;

k5_cc_mutex_lock(context, &krb5int_cc_file_mutex);
for (fccsp = &fccs; *fccsp != NULL; fccsp = &(*fccsp)->next) {
if ((*fccsp)->data == data)
break;
}
assert(*fccsp != NULL);
assert((*fccsp)->data == data);
(*fccsp)->refcount--;
if ((*fccsp)->refcount == 0) {
data = (*fccsp)->data;
temp = *fccsp;
*fccsp = (*fccsp)->next;
free(temp);
k5_cc_mutex_unlock(context, &krb5int_cc_file_mutex);
k5_cc_mutex_assert_unlocked(context, &data->lock);
free(data->filename);
zap(data->buf, sizeof(data->buf));
if (data->fd >= 0) {
k5_cc_mutex_lock(context, &data->lock);
close_cache_file(context, data);
k5_cc_mutex_unlock(context, &data->lock);
}
k5_cc_mutex_destroy(&data->lock);
free(data);
} else {
k5_cc_mutex_unlock(context, &krb5int_cc_file_mutex);
k5_cc_mutex_assert_unlocked(context, &data->lock);
free(data->filename);
zap(data->buf, sizeof(data->buf));
if (data->fd >= 0) {
k5_cc_mutex_lock(context, &data->lock);
close_cache_file(context, data);
k5_cc_mutex_unlock(context, &data->lock);
}
return 0;
k5_cc_mutex_destroy(&data->lock);
free(data);
}

/* Release the ccache handle. */
static krb5_error_code KRB5_CALLCONV
fcc_close(krb5_context context, krb5_ccache id)
{
dereference(context, id->data);
free_fccdata(context, id->data);
free(id);
return 0;
}
Expand Down Expand Up @@ -922,7 +895,7 @@ fcc_destroy(krb5_context context, krb5_ccache id)

cleanup:
k5_cc_mutex_unlock(context, &data->lock);
dereference(context, data);
free_fccdata(context, data);
free(id);

krb5_change_cache();
Expand All @@ -938,65 +911,30 @@ fcc_resolve(krb5_context context, krb5_ccache *id, const char *residual)
krb5_ccache lid;
krb5_error_code ret;
fcc_data *data;
struct fcc_set *setptr;

k5_cc_mutex_lock(context, &krb5int_cc_file_mutex);
for (setptr = fccs; setptr; setptr = setptr->next) {
if (!strcmp(setptr->data->filename, residual))
break;
data = malloc(sizeof(fcc_data));
if (data == NULL)
return KRB5_CC_NOMEM;
data->filename = strdup(residual);
if (data->filename == NULL) {
free(data);
return KRB5_CC_NOMEM;
}
if (setptr) {
data = setptr->data;
assert(setptr->refcount != 0);
setptr->refcount++;
assert(setptr->refcount != 0);
k5_cc_mutex_lock(context, &data->lock);
k5_cc_mutex_unlock(context, &krb5int_cc_file_mutex);
} else {
data = malloc(sizeof(fcc_data));
if (data == NULL) {
k5_cc_mutex_unlock(context, &krb5int_cc_file_mutex);
return KRB5_CC_NOMEM;
}
data->filename = strdup(residual);
if (data->filename == NULL) {
k5_cc_mutex_unlock(context, &krb5int_cc_file_mutex);
free(data);
return KRB5_CC_NOMEM;
}
ret = k5_cc_mutex_init(&data->lock);
if (ret) {
k5_cc_mutex_unlock(context, &krb5int_cc_file_mutex);
free(data->filename);
free(data);
return ret;
}
k5_cc_mutex_lock(context, &data->lock);
/* data->version,mode filled in for real later */
data->version = data->mode = 0;
data->fd = -1;
data->valid_bytes = 0;
setptr = malloc(sizeof(struct fcc_set));
if (setptr == NULL) {
k5_cc_mutex_unlock(context, &krb5int_cc_file_mutex);
k5_cc_mutex_unlock(context, &data->lock);
k5_cc_mutex_destroy(&data->lock);
free(data->filename);
free(data);
return KRB5_CC_NOMEM;
}
setptr->refcount = 1;
setptr->data = data;
setptr->next = fccs;
fccs = setptr;
k5_cc_mutex_unlock(context, &krb5int_cc_file_mutex);
ret = k5_cc_mutex_init(&data->lock);
if (ret) {
free(data->filename);
free(data);
return ret;
}

k5_cc_mutex_assert_locked(context, &data->lock);
k5_cc_mutex_unlock(context, &data->lock);
/* data->version,mode filled in for real later */
data->version = data->mode = 0;
data->fd = -1;
data->valid_bytes = 0;

lid = malloc(sizeof(struct _krb5_ccache));
if (lid == NULL) {
dereference(context, data);
free_fccdata(context, data);
return KRB5_CC_NOMEM;
}

Expand Down Expand Up @@ -1118,30 +1056,22 @@ krb5int_fcc_new_unique(krb5_context context, char *template, krb5_ccache *id)
char fcc_fvno[2];
int16_t fcc_flen = 0;
int errsave, cnt;
struct fcc_set *setptr;

/* Set master lock */
k5_cc_mutex_lock(context, &krb5int_cc_file_mutex);

fd = mkstemp(template);
if (fd == -1) {
k5_cc_mutex_unlock(context, &krb5int_cc_file_mutex);
if (fd == -1)
return interpret_errno(context, errno);
}
set_cloexec_fd(fd);

/* Allocate memory */
data = malloc(sizeof(fcc_data));
if (data == NULL) {
k5_cc_mutex_unlock(context, &krb5int_cc_file_mutex);
close(fd);
unlink(template);
return KRB5_CC_NOMEM;
}

data->filename = strdup(template);
if (data->filename == NULL) {
k5_cc_mutex_unlock(context, &krb5int_cc_file_mutex);
free(data);
close(fd);
unlink(template);
Expand All @@ -1150,7 +1080,6 @@ krb5int_fcc_new_unique(krb5_context context, char *template, krb5_ccache *id)

ret = k5_cc_mutex_init(&data->lock);
if (ret) {
k5_cc_mutex_unlock(context, &krb5int_cc_file_mutex);
free(data->filename);
free(data);
close(fd);
Expand Down Expand Up @@ -1202,27 +1131,11 @@ krb5int_fcc_new_unique(krb5_context context, char *template, krb5_ccache *id)
goto err_out;
}

setptr = malloc(sizeof(struct fcc_set));
if (setptr == NULL) {
k5_cc_mutex_unlock(context, &krb5int_cc_file_mutex);
k5_cc_mutex_unlock(context, &data->lock);
k5_cc_mutex_destroy(&data->lock);
free(data->filename);
free(data);
(void)unlink(template);
return KRB5_CC_NOMEM;
}
setptr->refcount = 1;
setptr->data = data;
setptr->next = fccs;
fccs = setptr;
k5_cc_mutex_unlock(context, &krb5int_cc_file_mutex);

k5_cc_mutex_assert_locked(context, &data->lock);
k5_cc_mutex_unlock(context, &data->lock);
lid = malloc(sizeof(*lid));
if (lid == NULL) {
dereference(context, data);
free_fccdata(context, data);
return KRB5_CC_NOMEM;
}

Expand All @@ -1236,7 +1149,6 @@ krb5int_fcc_new_unique(krb5_context context, char *template, krb5_ccache *id)
return 0;

err_out:
k5_cc_mutex_unlock(context, &krb5int_cc_file_mutex);
k5_cc_mutex_unlock(context, &data->lock);
k5_cc_mutex_destroy(&data->lock);
free(data->filename);
Expand Down

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