attach_probe selftest fails on Debian-based distros with `failed to resolve full path for 'libc.so.6'`. The reason is that these distros embraced multiarch to the point where even for the "main" architecture they store libc in /lib/<triple>. This is configured in /etc/ld.so.conf and in theory it's possible to replicate the loader's parsing and processing logic in libbpf, however a much simpler solution is to just enumerate the known library paths. Signed-off-by: Ilya Leoshkevich <iii@xxxxxxxxxxxxx> --- v1: https://lore.kernel.org/bpf/20220404102908.14688-1-iii@xxxxxxxxxxxxx/ v1 -> v2: Use a single return value (Andrii), get rid of nested #ifs, simplify some of the conditions. tools/lib/bpf/libbpf.c | 41 ++++++++++++++++++++++++++++++++++++++++- 1 file changed, 40 insertions(+), 1 deletion(-) diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 6d2be53e4ba9..648dc8717e8d 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -10707,15 +10707,54 @@ static long elf_find_func_offset(const char *binary_path, const char *name) return ret; } +static const char *arch_specific_lib_paths(void) +{ + /* + * Based on https://packages.debian.org/sid/libc6. + * + * Assume that the traced program is built for the same architecture + * as libbpf, which should cover the vast majority of cases. + */ +#if defined(__x86_64__) + return "/lib/x86_64-linux-gnu"; +#elif defined(__i386__) + return "/lib/i386-linux-gnu"; +#elif defined(__s390x__) + return "/lib/s390x-linux-gnu"; +#elif defined(__s390__) + return "/lib/s390-linux-gnu"; +#elif defined(__arm__) && defined(__SOFTFP__) + return "/lib/arm-linux-gnueabi"; +#elif defined(__arm__) && !defined(__SOFTFP__) + return "/lib/arm-linux-gnueabihf"; +#elif defined(__aarch64__) + return "/lib/aarch64-linux-gnu"; +#elif defined(__mips__) && defined(__MIPSEL__) && _MIPS_SZLONG == 64 + return "/lib/mips64el-linux-gnuabi64"; +#elif defined(__mips__) && defined(__MIPSEL__) && _MIPS_SZLONG == 32 + return "/lib/mipsel-linux-gnu"; +#elif defined(__powerpc64__) && __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__ + return "/lib/powerpc64le-linux-gnu"; +#elif defined(__sparc__) && defined(__arch64__) + return "/lib/sparc64-linux-gnu"; +#elif defined(__riscv) && __riscv_xlen == 64 + return "/lib/riscv64-linux-gnu"; +#else + return NULL; +#endif +} + /* Get full path to program/shared library. */ static int resolve_full_path(const char *file, char *result, size_t result_sz) { - const char *search_paths[2]; + const char *search_paths[3]; int i; + memset(search_paths, 0, sizeof(search_paths)); if (strstr(file, ".so")) { search_paths[0] = getenv("LD_LIBRARY_PATH"); search_paths[1] = "/usr/lib64:/usr/lib"; + search_paths[2] = arch_specific_lib_paths(); } else { search_paths[0] = getenv("PATH"); search_paths[1] = "/usr/bin:/usr/sbin"; -- 2.35.1
