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bpf: switch map 'pin_prefix' to 'pin_location'

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easy to do for maps now, but harder for programs

Test: TreeHugger
Flag: EXEMPT mainline
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Change-Id: I0aedef7a8f28d8cc60ca4912f2666f920b9dbeb5
This commit is contained in:
Maciej Żenczykowski 2025-07-30 18:21:48 -07:00
commit 47e2ba05ed
3 changed files with 17 additions and 19 deletions
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32
bpf/loader/NetBpfLoad.cpp
View file

@ -772,7 +772,7 @@ static bool isBtfSupported(enum bpf_map_type type) {
return type != BPF_MAP_TYPE_DEVMAP_HASH && type != BPF_MAP_TYPE_RINGBUF;
}
static int pinMap(const borrowed_fd& fd, const struct bpf_map_def& mapDef, const string& mapPinLoc) {
static int pinMap(const borrowed_fd& fd, const struct bpf_map_def& mapDef) {
int ret;
if (mapDef.create_location[0]) {
ret = bpfFdPin(fd, mapDef.create_location);
@ -782,32 +782,32 @@ static int pinMap(const borrowed_fd& fd, const struct bpf_map_def& mapDef, const
return -err;
}
ret = renameat2(AT_FDCWD, mapDef.create_location,
AT_FDCWD, mapPinLoc.c_str(), RENAME_NOREPLACE);
AT_FDCWD, mapDef.pin_location, RENAME_NOREPLACE);
if (ret) {
const int err = errno;
ALOGE("rename %s %s -> %d [%d:%s]", mapDef.create_location, mapPinLoc.c_str(), ret,
ALOGE("rename %s %s -> %d [%d:%s]", mapDef.create_location, mapDef.pin_location, ret,
err, strerror(err));
return -err;
}
} else {
ret = bpfFdPin(fd, mapPinLoc.c_str());
ret = bpfFdPin(fd, mapDef.pin_location);
if (ret) {
const int err = errno;
ALOGE("pin %s -> %d [%d:%s]", mapPinLoc.c_str(), ret, err, strerror(err));
ALOGE("pin %s -> %d [%d:%s]", mapDef.pin_location, ret, err, strerror(err));
return -err;
}
}
ret = chmod(mapPinLoc.c_str(), mapDef.mode);
ret = chmod(mapDef.pin_location, mapDef.mode);
if (ret) {
const int err = errno;
ALOGE("chmod(%s, 0%o) = %d [%d:%s]", mapPinLoc.c_str(), mapDef.mode, ret, err,
ALOGE("chmod(%s, 0%o) = %d [%d:%s]", mapDef.pin_location, mapDef.mode, ret, err,
strerror(err));
return -err;
}
ret = chown(mapPinLoc.c_str(), (uid_t)mapDef.uid, (gid_t)mapDef.gid);
ret = chown(mapDef.pin_location, (uid_t)mapDef.uid, (gid_t)mapDef.gid);
if (ret) {
const int err = errno;
ALOGE("chown(%s, %u, %u) = %d [%d:%s]", mapPinLoc.c_str(), mapDef.uid, mapDef.gid,
ALOGE("chown(%s, %u, %u) = %d [%d:%s]", mapDef.pin_location, mapDef.uid, mapDef.gid,
ret, err, strerror(err));
return -err;
}
@ -819,7 +819,7 @@ static int pinMap(const borrowed_fd& fd, const struct bpf_map_def& mapDef, const
ALOGE("bpfGetFdMapId failed, errno: %d", err);
return -err;
}
ALOGI("map %s id %d", mapPinLoc.c_str(), mapId);
ALOGI("map %s id %d", mapDef.pin_location, mapId);
}
return 0;
}
@ -952,12 +952,11 @@ static int createMaps(ifstream& elfFile, vector<unique_fd>& mapFds,
if (max_entries < page_size) max_entries = page_size;
}
string mapPinLoc = string(md[i].pin_prefix) + mapNames[i];
unique_fd fd;
int saved_errno;
if (access(mapPinLoc.c_str(), F_OK) == 0) {
fd.reset(mapRetrieveRO(mapPinLoc.c_str()));
if (access(md[i].pin_location, F_OK) == 0) {
fd.reset(mapRetrieveRO(md[i].pin_location));
saved_errno = errno;
ALOGD("bpf_create_map reusing map %s, ret: %d", mapNames[i].c_str(), fd.get());
abort();
@ -1001,7 +1000,7 @@ static int createMaps(ifstream& elfFile, vector<unique_fd>& mapFds,
// We assume failure is due to pinned map mismatch, hence the 'NOT UNIQUE' return code.
if (!mapMatchesExpectations(fd, mapNames[i], md[i], type)) return -ENOTUNIQ;
ret = pinMap(fd, md[i], mapPinLoc);
ret = pinMap(fd, md[i]);
if (ret) return ret;
mapFds.push_back(std::move(fd));
@ -1344,13 +1343,12 @@ static int pinMaps(const struct bpf_object* obj,
// This map was skipped
if (!bpf_map__autocreate(m)) continue;
string mapPinLoc = string(md[i].pin_prefix) + mapNames[i];
if (access(mapPinLoc.c_str(), F_OK) == 0) {
if (access(md[i].pin_location, F_OK) == 0) {
ALOGE("Reusing map is not supported: %s", mapNames[i].c_str());
return -1;
}
ret = pinMap(bpf_map__fd(m), md[i], mapPinLoc);
ret = pinMap(bpf_map__fd(m), md[i]);
if (ret) return ret;
}
return 0;

2
bpf/progs/include/bpf_helpers.h
View file

@ -260,7 +260,7 @@ static int (*bpf_sk_storage_delete_unsafe) (const void* sk_storage,
.min_kver = (minkver).kver, \
.max_kver = (maxkver).kver, \
.create_location = CREATE_LOCATION(selinux), \
.pin_prefix = "/sys/fs/bpf/" pindir "/map_" BPF_OBJ_NAME "_", \
.pin_location = "/sys/fs/bpf/" pindir "/map_" BPF_OBJ_NAME "_" #the_map, \
};
#define __uint(name, val) int (*name)[val]

2
bpf/progs/include/bpf_map_def.h
View file

@ -143,7 +143,7 @@ struct bpf_map_def {
// These are fixed length ASCIIZ strings, padded with null bytes
char create_location[BPF_DEF_CHAR_ARRAY_SIZE];
char pin_prefix[BPF_DEF_CHAR_ARRAY_SIZE];
char pin_location[BPF_DEF_CHAR_ARRAY_SIZE];
};
// This needs to be updated whenever the above structure definition is expanded.