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vendorBpfLoader: no need for locations array

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Afterwards we still have:
  I BpfLoader: Platform BpfLoader loading critical for healthd ELF object /vendor/etc/bpf/filterPowerSupplyEvents.o with license Apache 2.0
  W BpfLoader: No maps section could be found in elf object
  D BpfLoader: prog /sys/fs/bpf/vendor/prog_filterPowerSupplyEvents_skfilter_power_supply id 82

  $ adbz shell ls -lZ /sys/fs/bpf /sys/fs/bpf/vendor
  /sys/fs/bpf:
  total 0
  ...
  drwxrwxrwt 2 root root     u:object_r:fs_bpf_vendor:s0          0 2025-07-15 23:53 vendor

  /sys/fs/bpf/vendor:
  total 0
  -r--r----- 1 root system u:object_r:fs_bpf_vendor:s0  0 2025-07-15 23:53 prog_filterPowerSupplyEvents_skfilter_power_supply

Test: TreeHugger
Flag: EXEMPT no-op
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Change-Id: I66a6fc3abf8f5c4c52f6a47476c251e97f1f6e14
This commit is contained in:
Maciej Żenczykowski 2025-07-15 23:37:11 -07:00
commit c30b4f8bee
1 changed files with 30 additions and 59 deletions
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89
loader/Loader.cpp
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@ -51,8 +51,6 @@
#include <android-base/strings.h>
#include <android-base/unique_fd.h>
#define BPF_FS_PATH "/sys/fs/bpf/"
// Size of the BPF log buffer for verifier logging
#define BPF_LOAD_LOG_SZ 0xfffff
@ -481,8 +479,7 @@ static bool mapMatchesExpectations(const unique_fd& fd, const string& mapName,
return false;
}
static int createMaps(const char* elfPath, ifstream& elfFile, vector<unique_fd>& mapFds,
const char* prefix) {
static int createMaps(const char* elfPath, ifstream& elfFile, vector<unique_fd>& mapFds) {
int ret;
vector<char> mdData;
vector<struct bpf_map_def> md;
@ -546,7 +543,7 @@ static int createMaps(const char* elfPath, ifstream& elfFile, vector<unique_fd>&
// Format of pin location is /sys/fs/bpf/<prefix>map_<objName>_<mapName>
// except that maps shared across .o's have empty <objName>
// Note: <objName> refers to the extension-less basename of the .o file (without @ suffix).
string mapPinLoc = string(BPF_FS_PATH) + prefix + "map_" +
string mapPinLoc = string("/sys/fs/bpf/vendor/map_") +
(md[i].shared ? "" : objName) + "_" + mapNames[i];
bool reuse = false;
unique_fd fd;
@ -667,8 +664,7 @@ static void applyMapRelo(ifstream& elfFile, vector<unique_fd> &mapFds, vector<co
}
}
static int loadCodeSections(const char* elfPath, vector<codeSection>& cs, const string& license,
const char* prefix) {
static int loadCodeSections(const char* elfPath, vector<codeSection>& cs, const string& license) {
unsigned kvers = kernelVersion();
if (!kvers) {
@ -704,8 +700,7 @@ static int loadCodeSections(const char* elfPath, vector<codeSection>& cs, const
bool reuse = false;
// Format of pin location is
// /sys/fs/bpf/<prefix>prog_<objName>_<progName>
string progPinLoc = string(BPF_FS_PATH) + prefix + "prog_" +
objName + '_' + string(name);
string progPinLoc = string("/sys/fs/bpf/vendor/prog_") + objName + '_' + name;
if (access(progPinLoc.c_str(), F_OK) == 0) {
fd.reset(retrieveProgram(progPinLoc.c_str()));
ALOGV("New bpf prog load reusing prog %s, ret: %d (%s)", progPinLoc.c_str(), fd.get(),
@ -779,12 +774,7 @@ static int loadCodeSections(const char* elfPath, vector<codeSection>& cs, const
return 0;
}
struct Location {
const char* const dir = "";
const char* const prefix = "";
};
int loadProg(const char* elfPath, bool* isCritical, const Location& location) {
int loadProg(const char* elfPath, bool* isCritical) {
vector<char> license;
vector<char> critical;
vector<codeSection> cs;
@ -816,7 +806,7 @@ int loadProg(const char* elfPath, bool* isCritical, const Location& location) {
return ret;
}
ret = createMaps(elfPath, elfFile, mapFds, location.prefix);
ret = createMaps(elfPath, elfFile, mapFds);
if (ret) {
ALOGE("Failed to create maps: (ret=%d) in %s", ret, elfPath);
return ret;
@ -827,35 +817,27 @@ int loadProg(const char* elfPath, bool* isCritical, const Location& location) {
applyMapRelo(elfFile, mapFds, cs);
ret = loadCodeSections(elfPath, cs, string(license.data()), location.prefix);
ret = loadCodeSections(elfPath, cs, string(license.data()));
if (ret) ALOGE("Failed to load programs, loadCodeSections ret=%d", ret);
return ret;
}
const Location locations[] = {
// Vendor operating system
{
.dir = "/vendor/etc/bpf/",
.prefix = "vendor/",
},
};
int loadAllElfObjects(const Location& location) {
int loadAllElfObjects() {
int retVal = 0;
DIR* dir;
struct dirent* ent;
if ((dir = opendir(location.dir)) != NULL) {
if ((dir = opendir("/vendor/etc/bpf/")) != NULL) {
while ((ent = readdir(dir)) != NULL) {
string s = ent->d_name;
if (!EndsWith(s, ".o")) continue;
string progPath(location.dir);
string progPath("/vendor/etc/bpf/");
progPath += s;
bool critical;
int ret = loadProg(progPath.c_str(), &critical, location);
int ret = loadProg(progPath.c_str(), &critical);
if (ret) {
if (critical) retVal = ret;
ALOGE("Failed to load object: %s, ret: %s", progPath.c_str(), strerror(-ret));
@ -868,23 +850,18 @@ int loadAllElfObjects(const Location& location) {
return retVal;
}
int createSysFsBpfSubDir(const char* const prefix) {
if (*prefix) {
mode_t prevUmask = umask(0);
int createSysFsBpfVendor() {
mode_t prevUmask = umask(0);
string s = "/sys/fs/bpf/";
s += prefix;
errno = 0;
int ret = mkdir(s.c_str(), S_ISVTX | S_IRWXU | S_IRWXG | S_IRWXO);
if (ret && errno != EEXIST) {
const int err = errno;
ALOGE("Failed to create directory: %s, ret: %s", s.c_str(), strerror(err));
return -err;
}
umask(prevUmask);
errno = 0;
int ret = mkdir("/sys/fs/bpf/vendor", S_ISVTX | S_IRWXU | S_IRWXG | S_IRWXO);
if (ret && errno != EEXIST) {
const int err = errno;
ALOGE("Failed to create directory: /sys/fs/bpf/vendor, ret: %s", strerror(err));
return -err;
}
umask(prevUmask);
return 0;
}
@ -900,23 +877,17 @@ void vendorBpfLoader() {
const char* argv[] = {"/system/bin/bpfloader", NULL};
android::base::InitLogging(const_cast<char**>(argv), &android::base::KernelLogger);
for (const auto& location : android::bpf::locations) {
if (android::bpf::createSysFsBpfSubDir(location.prefix)) {
exit(120);
}
}
if (android::bpf::createSysFsBpfVendor()) exit(120);
// Load all ELF objects, create programs and maps, and pin them
for (const auto& location : android::bpf::locations) {
if (android::bpf::loadAllElfObjects(location)) {
ALOGE("=== CRITICAL FAILURE LOADING BPF PROGRAMS FROM %s ===", location.dir);
ALOGE("If this triggers reliably, you're probably missing kernel options or patches.");
ALOGE("If this triggers randomly, you might be hitting some memory allocation "
"problems or startup script race.");
ALOGE("--- DO NOT EXPECT SYSTEM TO BOOT SUCCESSFULLY ---");
sleep(20);
exit(121);
}
if (android::bpf::loadAllElfObjects()) {
ALOGE("=== CRITICAL FAILURE LOADING BPF PROGRAMS FROM /vendor/etc/bpf ===");
ALOGE("If this triggers reliably, you're probably missing kernel options or patches.");
ALOGE("If this triggers randomly, you might be hitting some memory allocation "
"problems or startup script race.");
ALOGE("--- DO NOT EXPECT SYSTEM TO BOOT SUCCESSFULLY ---");
sleep(20);
exit(121);
}
const char* args[] = {"/apex/com.android.tethering/bin/netbpfload", "done", NULL};