From 1ce6a9fc154935d9db771173ecde03fa9b42df4a Mon Sep 17 00:00:00 2001 From: Thomas Richter Date: Mon, 30 Jul 2018 10:53:23 +0200 Subject: [PATCH] bpf: fix build error in libbpf with EXTRA_CFLAGS="-Wp, -D_FORTIFY_SOURCE=2 -O2" MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Commit 531b014e7a2f ("tools: bpf: make use of reallocarray") causes a compiler error when building the perf tool in the linux-next tree. Compile file tools/lib/bpf/libbpf.c on a FEDORA 28 installation with gcc compiler version: gcc (GCC) 8.0.1 20180324 (Red Hat 8.0.1-0.20) shows this error message: [root@p23lp27] # make V=1 EXTRA_CFLAGS="-Wp,-D_FORTIFY_SOURCE=2 -O2" [...] make -f /home6/tmricht/linux-next/tools/build/Makefile.build dir=./util/scripting-engines obj=libperf libbpf.c: In function ‘bpf_object__elf_collect’: libbpf.c:811:15: error: ignoring return value of ‘strerror_r’, declared with attribute warn_unused_result [-Werror=unused-result] strerror_r(-err, errmsg, sizeof(errmsg)); ^ cc1: all warnings being treated as errors mv: cannot stat './.libbpf.o.tmp': No such file or directory /home6/tmricht/linux-next/tools/build/Makefile.build:96: recipe for target 'libbpf.o' failed Replace all occurrences of strerror() by calls to strerror_r(). To keep the compiler quiet also use the return value from strerror_r() otherwise a 'variable set but not use' warning which is treated as error terminates the compile. Fixes: 531b014e7a2f ("tools: bpf: make use of reallocarray") Suggested-by: Jakub Kicinski Suggested-by: Daniel Borkmann Signed-off-by: Thomas Richter Reviewed-by: Hendrik Brueckner Reviewed-by: Jakub Kicinski Signed-off-by: Daniel Borkmann --- tools/lib/bpf/libbpf.c | 42 +++++++++++++++++++++++++++++------------- 1 file changed, 29 insertions(+), 13 deletions(-) diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 857d3d16968e..79fc7ed6995a 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -467,8 +467,10 @@ static int bpf_object__elf_init(struct bpf_object *obj) } else { obj->efile.fd = open(obj->path, O_RDONLY); if (obj->efile.fd < 0) { - pr_warning("failed to open %s: %s\n", obj->path, - strerror(errno)); + char errmsg[STRERR_BUFSIZE]; + char *cp = strerror_r(errno, errmsg, sizeof(errmsg)); + + pr_warning("failed to open %s: %s\n", obj->path, cp); return -errno; } @@ -807,10 +809,11 @@ static int bpf_object__elf_collect(struct bpf_object *obj) data->d_size, name, idx); if (err) { char errmsg[STRERR_BUFSIZE]; + char *cp = strerror_r(-err, errmsg, + sizeof(errmsg)); - strerror_r(-err, errmsg, sizeof(errmsg)); pr_warning("failed to alloc program %s (%s): %s", - name, obj->path, errmsg); + name, obj->path, cp); } } else if (sh.sh_type == SHT_REL) { void *reloc = obj->efile.reloc; @@ -1104,6 +1107,7 @@ bpf_object__create_maps(struct bpf_object *obj) for (i = 0; i < obj->nr_maps; i++) { struct bpf_map *map = &obj->maps[i]; struct bpf_map_def *def = &map->def; + char *cp, errmsg[STRERR_BUFSIZE]; int *pfd = &map->fd; if (map->fd >= 0) { @@ -1131,8 +1135,9 @@ bpf_object__create_maps(struct bpf_object *obj) *pfd = bpf_create_map_xattr(&create_attr); if (*pfd < 0 && create_attr.btf_key_type_id) { + cp = strerror_r(errno, errmsg, sizeof(errmsg)); pr_warning("Error in bpf_create_map_xattr(%s):%s(%d). Retrying without BTF.\n", - map->name, strerror(errno), errno); + map->name, cp, errno); create_attr.btf_fd = 0; create_attr.btf_key_type_id = 0; create_attr.btf_value_type_id = 0; @@ -1145,9 +1150,9 @@ bpf_object__create_maps(struct bpf_object *obj) size_t j; err = *pfd; + cp = strerror_r(errno, errmsg, sizeof(errmsg)); pr_warning("failed to create map (name: '%s'): %s\n", - map->name, - strerror(errno)); + map->name, cp); for (j = 0; j < i; j++) zclose(obj->maps[j].fd); return err; @@ -1299,6 +1304,7 @@ load_program(enum bpf_prog_type type, enum bpf_attach_type expected_attach_type, char *license, u32 kern_version, int *pfd, int prog_ifindex) { struct bpf_load_program_attr load_attr; + char *cp, errmsg[STRERR_BUFSIZE]; char *log_buf; int ret; @@ -1328,7 +1334,8 @@ load_program(enum bpf_prog_type type, enum bpf_attach_type expected_attach_type, } ret = -LIBBPF_ERRNO__LOAD; - pr_warning("load bpf program failed: %s\n", strerror(errno)); + cp = strerror_r(errno, errmsg, sizeof(errmsg)); + pr_warning("load bpf program failed: %s\n", cp); if (log_buf && log_buf[0] != '\0') { ret = -LIBBPF_ERRNO__VERIFY; @@ -1627,6 +1634,7 @@ int bpf_object__load(struct bpf_object *obj) static int check_path(const char *path) { + char *cp, errmsg[STRERR_BUFSIZE]; struct statfs st_fs; char *dname, *dir; int err = 0; @@ -1640,7 +1648,8 @@ static int check_path(const char *path) dir = dirname(dname); if (statfs(dir, &st_fs)) { - pr_warning("failed to statfs %s: %s\n", dir, strerror(errno)); + cp = strerror_r(errno, errmsg, sizeof(errmsg)); + pr_warning("failed to statfs %s: %s\n", dir, cp); err = -errno; } free(dname); @@ -1656,6 +1665,7 @@ static int check_path(const char *path) int bpf_program__pin_instance(struct bpf_program *prog, const char *path, int instance) { + char *cp, errmsg[STRERR_BUFSIZE]; int err; err = check_path(path); @@ -1674,7 +1684,8 @@ int bpf_program__pin_instance(struct bpf_program *prog, const char *path, } if (bpf_obj_pin(prog->instances.fds[instance], path)) { - pr_warning("failed to pin program: %s\n", strerror(errno)); + cp = strerror_r(errno, errmsg, sizeof(errmsg)); + pr_warning("failed to pin program: %s\n", cp); return -errno; } pr_debug("pinned program '%s'\n", path); @@ -1684,13 +1695,16 @@ int bpf_program__pin_instance(struct bpf_program *prog, const char *path, static int make_dir(const char *path) { + char *cp, errmsg[STRERR_BUFSIZE]; int err = 0; if (mkdir(path, 0700) && errno != EEXIST) err = -errno; - if (err) - pr_warning("failed to mkdir %s: %s\n", path, strerror(-err)); + if (err) { + cp = strerror_r(-err, errmsg, sizeof(errmsg)); + pr_warning("failed to mkdir %s: %s\n", path, cp); + } return err; } @@ -1737,6 +1751,7 @@ int bpf_program__pin(struct bpf_program *prog, const char *path) int bpf_map__pin(struct bpf_map *map, const char *path) { + char *cp, errmsg[STRERR_BUFSIZE]; int err; err = check_path(path); @@ -1749,7 +1764,8 @@ int bpf_map__pin(struct bpf_map *map, const char *path) } if (bpf_obj_pin(map->fd, path)) { - pr_warning("failed to pin map: %s\n", strerror(errno)); + cp = strerror_r(errno, errmsg, sizeof(errmsg)); + pr_warning("failed to pin map: %s\n", cp); return -errno; } -- 2.45.2