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vendorBpfLoader: error handling simplifications

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We continue to have:
  $ adb shell ls -lZ /sys/fs/bpf/vendor
  total 0
  -r--r----- 1 root system u:object_r:fs_bpf_vendor:s0  0 2025-07-16 09:37 prog_filterPowerSupplyEvents_skfilter_power_supply

Test: TreeHugger
Flag: EXEMPT no-op
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Change-Id: I2be675467688cf5f9c651b8311dceb68744100a8
This commit is contained in:
Maciej Żenczykowski 2025-07-16 09:35:03 -07:00
commit b073360177
1 changed files with 14 additions and 35 deletions
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49
loader/Loader.cpp
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@ -101,10 +101,8 @@ static int readElfHeader(ifstream& elfFile, Elf64_Ehdr* eh) {
// Reads all section header tables into an Shdr array
static int readSectionHeadersAll(ifstream& elfFile, vector<Elf64_Shdr>& shTable) {
Elf64_Ehdr eh;
int ret = 0;
ret = readElfHeader(elfFile, &eh);
if (ret) return ret;
if (readElfHeader(elfFile, &eh)) return -1;
elfFile.seekg(eh.e_shoff);
if (elfFile.fail()) return -1;
@ -112,7 +110,7 @@ static int readSectionHeadersAll(ifstream& elfFile, vector<Elf64_Shdr>& shTable)
// Read shdr table entries
shTable.resize(eh.e_shnum);
if (!elfFile.read((char*)shTable.data(), (eh.e_shnum * eh.e_shentsize))) return -ENOMEM;
if (!elfFile.read((char*)shTable.data(), eh.e_shnum * eh.e_shentsize)) return -1;
return 0;
}
@ -120,8 +118,7 @@ static int readSectionHeadersAll(ifstream& elfFile, vector<Elf64_Shdr>& shTable)
// Read a section by its index - for ex to get sec hdr strtab blob
static int readSectionByIdx(ifstream& elfFile, int id, vector<char>& sec) {
vector<Elf64_Shdr> shTable;
int ret = readSectionHeadersAll(elfFile, shTable);
if (ret) return ret;
if (readSectionHeadersAll(elfFile, shTable)) return -1;
elfFile.seekg(shTable[id].sh_offset);
if (elfFile.fail()) return -1;
@ -135,45 +132,33 @@ static int readSectionByIdx(ifstream& elfFile, int id, vector<char>& sec) {
// Read whole section header string table
static int readSectionHeaderStrtab(ifstream& elfFile, vector<char>& strtab) {
Elf64_Ehdr eh;
int ret = readElfHeader(elfFile, &eh);
if (ret) return ret;
ret = readSectionByIdx(elfFile, eh.e_shstrndx, strtab);
if (ret) return ret;
if (readElfHeader(elfFile, &eh)) return -1;
if (readSectionByIdx(elfFile, eh.e_shstrndx, strtab)) return -1;
return 0;
}
// Get name from offset in strtab
static int getSymName(ifstream& elfFile, int nameOff, string& name) {
int ret;
vector<char> secStrTab;
ret = readSectionHeaderStrtab(elfFile, secStrTab);
if (ret) return ret;
if (readSectionHeaderStrtab(elfFile, secStrTab)) return -1;
if (nameOff >= (int)secStrTab.size()) return -1;
name = string((char*)secStrTab.data() + nameOff);
name = string(secStrTab.data() + nameOff);
return 0;
}
// Reads a full section by name - example to get the GPL license
template <typename T>
static int readSectionByName(const char* name, ifstream& elfFile, vector<T>& data) {
vector<char> secStrTab;
vector<Elf64_Shdr> shTable;
int ret;
if (readSectionHeadersAll(elfFile, shTable)) return -1;
ret = readSectionHeadersAll(elfFile, shTable);
if (ret) return ret;
ret = readSectionHeaderStrtab(elfFile, secStrTab);
if (ret) return ret;
vector<char> secStrTab;
if (readSectionHeaderStrtab(elfFile, secStrTab)) return -1;
for (int i = 0; i < (int)shTable.size(); i++) {
char* secname = secStrTab.data() + shTable[i].sh_name;
if (!secname) continue;
if (!strcmp(secname, name)) {
elfFile.seekg(shTable[i].sh_offset);
@ -191,11 +176,8 @@ static int readSectionByName(const char* name, ifstream& elfFile, vector<T>& dat
}
static int readSectionByType(ifstream& elfFile, int type, vector<char>& data) {
int ret;
vector<Elf64_Shdr> shTable;
ret = readSectionHeadersAll(elfFile, shTable);
if (ret) return ret;
if (readSectionHeadersAll(elfFile, shTable)) return -1;
for (int i = 0; i < (int)shTable.size(); i++) {
if ((int)shTable[i].sh_type != type) continue;
@ -216,15 +198,12 @@ static bool symCompare(Elf64_Sym a, Elf64_Sym b) {
}
static int readSymTab(ifstream& elfFile, int sort, vector<Elf64_Sym>& data) {
int ret, numElems;
Elf64_Sym* buf;
vector<char> secData;
ret = readSectionByType(elfFile, SHT_SYMTAB, secData);
int ret = readSectionByType(elfFile, SHT_SYMTAB, secData);
if (ret) return ret;
buf = (Elf64_Sym*)secData.data();
numElems = (secData.size() / sizeof(Elf64_Sym));
Elf64_Sym* buf = (Elf64_Sym*)secData.data();
int numElems = secData.size() / sizeof(Elf64_Sym);
data.assign(buf, buf + numElems);
if (sort) std::sort(data.begin(), data.end(), symCompare);