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shared/capability: go frugal on space for caps

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This commit is contained in:
Zbigniew Jędrzejewski-Szmek
2015-02-01 15:26:46 -05:00
parent 51ddf61540
commit 7d328b5446
2 changed files with 14 additions and 3 deletions
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5
src/shared/capability.c
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@@ -269,11 +269,12 @@ int drop_privileges(uid_t uid, gid_t gid, uint64_t keep_capabilities) {
return log_oom(); return log_oom();
if (keep_capabilities) { if (keep_capabilities) {
cap_value_t bits[sizeof(keep_capabilities)*8]; cap_value_t bits[log2u64(keep_capabilities)];
for (i = 0; i < sizeof(keep_capabilities)*8; i++) for (i = 0; i < ELEMENTSOF(bits); i++)
if (keep_capabilities & (1ULL << i)) if (keep_capabilities & (1ULL << i))
bits[j++] = i; bits[j++] = i;
assert((keep_capabilities & (~1ULL << i)) == 0);
if (cap_set_flag(d, CAP_EFFECTIVE, j, bits, CAP_SET) < 0 || if (cap_set_flag(d, CAP_EFFECTIVE, j, bits, CAP_SET) < 0 ||
cap_set_flag(d, CAP_PERMITTED, j, bits, CAP_SET) < 0) { cap_set_flag(d, CAP_PERMITTED, j, bits, CAP_SET) < 0) {

12
src/shared/util.h
View File

@@ -860,7 +860,7 @@ static inline unsigned u32ctz(uint32_t n) {
#endif #endif
} }
static inline int log2i(int x) { static inline unsigned log2i(int x) {
assert(x > 0); assert(x > 0);
return __SIZEOF_INT__ * 8 - __builtin_clz(x) - 1; return __SIZEOF_INT__ * 8 - __builtin_clz(x) - 1;
@@ -872,6 +872,16 @@ static inline unsigned log2u(unsigned x) {
return sizeof(unsigned) * 8 - __builtin_clz(x) - 1; return sizeof(unsigned) * 8 - __builtin_clz(x) - 1;
} }
static inline unsigned log2u64(uint64_t x) {
assert(x > 0);
#if __SIZEOF_LONG_LONG__ == 8
return 64 - __builtin_clzll(x) - 1;
#else
#error "Wut?"
#endif
}
static inline unsigned log2u_round_up(unsigned x) { static inline unsigned log2u_round_up(unsigned x) {
assert(x > 0); assert(x > 0);