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sd-journal: fix sd_journal_enumerate_unique skipping values

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sd_journal_enumerate_unique will lock its mmap window to prevent it
from being released by calling mmap_cache_get with keep_always=true.
This call may return windows that are wider, but compatible with the
parameters provided to it.

This can result in a mismatch where the window to be released cannot
properly be selected, because we have more than one window matching the
parameters of mmap_cache_release. Therefore, introduce a release_cookie
to be used when releasing the window.

https://bugs.freedesktop.org/show_bug.cgi?id=79380
This commit is contained in:
Jan Janssen 2014-09-06 10:36:34 +02:00 committed by Zbigniew Jędrzejewski-Szmek
parent 853bd5cc72
commit 06cc69d44c
7 changed files with 39 additions and 37 deletions
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2
src/journal/journal-file.c
View File

@ -391,7 +391,7 @@ static int journal_file_move_to(JournalFile *f, int context, bool keep_always, u
return -EADDRNOTAVAIL;
}
return mmap_cache_get(f->mmap, f->fd, f->prot, context, keep_always, offset, size, &f->last_stat, ret);
return mmap_cache_get(f->mmap, f->fd, f->prot, context, keep_always, offset, size, &f->last_stat, ret, NULL);
}
static uint64_t minimum_header_size(Object *o) {

11
src/journal/journal-file.h
View File

@ -212,17 +212,14 @@ static unsigned type_to_context(int type) {
return type > 0 && type < _OBJECT_TYPE_MAX ? type : 0;
}
static inline int journal_file_object_keep(JournalFile *f, Object *o, uint64_t offset) {
static inline int journal_file_object_keep(JournalFile *f, Object *o, uint64_t offset, void **release_cookie) {
unsigned context = type_to_context(o->object.type);
uint64_t s = le64toh(o->object.size);
return mmap_cache_get(f->mmap, f->fd, f->prot, context, true,
offset, s, &f->last_stat, NULL);
offset, s, &f->last_stat, NULL, release_cookie);
}
static inline int journal_file_object_release(JournalFile *f, Object *o, uint64_t offset) {
unsigned context = type_to_context(o->object.type);
uint64_t s = le64toh(o->object.size);
return mmap_cache_release(f->mmap, f->fd, f->prot, context, offset, s);
static inline int journal_file_object_release(JournalFile *f, void *release_cookie) {
return mmap_cache_release(f->mmap, f->fd, release_cookie);
}

2
src/journal/journal-verify.c
View File

@ -368,7 +368,7 @@ static int contains_uint64(MMapCache *m, int fd, uint64_t n, uint64_t p) {
c = (a + b) / 2;
r = mmap_cache_get(m, fd, PROT_READ|PROT_WRITE, 0, false, c * sizeof(uint64_t), sizeof(uint64_t), NULL, (void **) &z);
r = mmap_cache_get(m, fd, PROT_READ|PROT_WRITE, 0, false, c * sizeof(uint64_t), sizeof(uint64_t), NULL, (void **) &z, NULL);
if (r < 0)
return r;

32
src/journal/mmap-cache.c
View File

@ -352,7 +352,8 @@ static int try_context(
bool keep_always,
uint64_t offset,
size_t size,
void **ret) {
void **ret,
void **release_cookie) {
Context *c;
@ -381,6 +382,8 @@ static int try_context(
if (ret)
*ret = (uint8_t*) c->window->ptr + (offset - c->window->offset);
if (keep_always && release_cookie)
*release_cookie = c->window;
return 1;
}
@ -392,7 +395,8 @@ static int find_mmap(
bool keep_always,
uint64_t offset,
size_t size,
void **ret) {
void **ret,
void **release_cookie) {
FileDescriptor *f;
Window *w;
@ -425,6 +429,8 @@ static int find_mmap(
if (ret)
*ret = (uint8_t*) w->ptr + (offset - w->offset);
if (keep_always && release_cookie)
*release_cookie = c->window;
return 1;
}
@ -437,7 +443,8 @@ static int add_mmap(
uint64_t offset,
size_t size,
struct stat *st,
void **ret) {
void **ret,
void **release_cookie) {
uint64_t woffset, wsize;
Context *c;
@ -521,6 +528,8 @@ static int add_mmap(
if (ret)
*ret = (uint8_t*) w->ptr + (offset - w->offset);
if (keep_always && release_cookie)
*release_cookie = c->window;
return 1;
outofmem:
@ -537,7 +546,8 @@ int mmap_cache_get(
uint64_t offset,
size_t size,
struct stat *st,
void **ret) {
void **ret,
void **release_cookie) {
int r;
@ -547,14 +557,14 @@ int mmap_cache_get(
assert(size > 0);
/* Check whether the current context is the right one already */
r = try_context(m, fd, prot, context, keep_always, offset, size, ret);
r = try_context(m, fd, prot, context, keep_always, offset, size, ret, release_cookie);
if (r != 0) {
m->n_hit ++;
return r;
}
/* Search for a matching mmap */
r = find_mmap(m, fd, prot, context, keep_always, offset, size, ret);
r = find_mmap(m, fd, prot, context, keep_always, offset, size, ret, release_cookie);
if (r != 0) {
m->n_hit ++;
return r;
@ -563,16 +573,13 @@ int mmap_cache_get(
m->n_missed++;
/* Create a new mmap */
return add_mmap(m, fd, prot, context, keep_always, offset, size, st, ret);
return add_mmap(m, fd, prot, context, keep_always, offset, size, st, ret, release_cookie);
}
int mmap_cache_release(
MMapCache *m,
int fd,
int prot,
unsigned context,
uint64_t offset,
size_t size) {
void *release_cookie) {
FileDescriptor *f;
Window *w;
@ -580,7 +587,6 @@ int mmap_cache_release(
assert(m);
assert(m->n_ref > 0);
assert(fd >= 0);
assert(size > 0);
f = hashmap_get(m->fds, INT_TO_PTR(fd + 1));
if (!f)
@ -589,7 +595,7 @@ int mmap_cache_release(
assert(f->fd == fd);
LIST_FOREACH(by_fd, w, f->windows)
if (window_matches(w, fd, prot, offset, size))
if (w == release_cookie)
break;
if (!w)

8
src/journal/mmap-cache.h
View File

@ -40,14 +40,12 @@ int mmap_cache_get(
uint64_t offset,
size_t size,
struct stat *st,
void **ret);
void **ret,
void **release_cookie);
int mmap_cache_release(
MMapCache *m,
int fd,
int prot,
unsigned context,
uint64_t offset,
size_t size);
void *release_cookie);
void mmap_cache_close_fd(MMapCache *m, int fd);
void mmap_cache_close_context(MMapCache *m, unsigned context);

11
src/journal/sd-journal.c
View File

@ -2528,6 +2528,7 @@ _public_ int sd_journal_enumerate_unique(sd_journal *j, const void **data, size_
size_t ol;
bool found;
int r;
void *release_cookie;
/* Proceed to next data object in the field's linked list */
if (j->unique_offset == 0) {
@ -2568,7 +2569,7 @@ _public_ int sd_journal_enumerate_unique(sd_journal *j, const void **data, size_
return -EBADMSG;
}
r = journal_file_object_keep(j->unique_file, o, j->unique_offset);
r = journal_file_object_keep(j->unique_file, o, j->unique_offset, &release_cookie);
if (r < 0)
return r;
@ -2616,13 +2617,13 @@ _public_ int sd_journal_enumerate_unique(sd_journal *j, const void **data, size_
found = true;
}
if (found)
continue;
r = journal_file_object_release(j->unique_file, o, j->unique_offset);
r = journal_file_object_release(j->unique_file, release_cookie);
if (r < 0)
return r;
if (found)
continue;
r = return_data(j, j->unique_file, o, data, l);
if (r < 0)
return r;

10
src/journal/test-mmap-cache.c
View File

@ -49,23 +49,23 @@ int main(int argc, char *argv[]) {
assert(z >= 0);
unlink(pz);
r = mmap_cache_get(m, x, PROT_READ, 0, false, 1, 2, NULL, &p);
r = mmap_cache_get(m, x, PROT_READ, 0, false, 1, 2, NULL, &p, NULL);
assert(r >= 0);
r = mmap_cache_get(m, x, PROT_READ, 0, false, 2, 2, NULL, &q);
r = mmap_cache_get(m, x, PROT_READ, 0, false, 2, 2, NULL, &q, NULL);
assert(r >= 0);
assert((uint8_t*) p + 1 == (uint8_t*) q);
r = mmap_cache_get(m, x, PROT_READ, 1, false, 3, 2, NULL, &q);
r = mmap_cache_get(m, x, PROT_READ, 1, false, 3, 2, NULL, &q, NULL);
assert(r >= 0);
assert((uint8_t*) p + 2 == (uint8_t*) q);
r = mmap_cache_get(m, x, PROT_READ, 0, false, 16ULL*1024ULL*1024ULL, 2, NULL, &p);
r = mmap_cache_get(m, x, PROT_READ, 0, false, 16ULL*1024ULL*1024ULL, 2, NULL, &p, NULL);
assert(r >= 0);
r = mmap_cache_get(m, x, PROT_READ, 1, false, 16ULL*1024ULL*1024ULL+1, 2, NULL, &q);
r = mmap_cache_get(m, x, PROT_READ, 1, false, 16ULL*1024ULL*1024ULL+1, 2, NULL, &q, NULL);
assert(r >= 0);
assert((uint8_t*) p + 1 == (uint8_t*) q);