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authorAndrii Nakryiko <andriin@fb.com>2019-12-13 17:47:09 -0800
committerAlexei Starovoitov <ast@kernel.org>2019-12-15 16:41:12 -0800
commit2ad97d473db57ab866f0756806bb94515f7f2551 (patch)
tree6823aff4884341d6aa088f33cc1504375a6d2504 /tools/lib/bpf/libbpf.c
parentlibbpf: Support libbpf-provided extern variables (diff)
downloadlinux-dev-2ad97d473db57ab866f0756806bb94515f7f2551.tar.xz
linux-dev-2ad97d473db57ab866f0756806bb94515f7f2551.zip
bpftool: Generate externs datasec in BPF skeleton
Add support for generation of mmap()-ed read-only view of libbpf-provided extern variables. As externs are not supposed to be provided by user code (that's what .data, .bss, and .rodata is for), don't mmap() it initially. Only after skeleton load is performed, map .extern contents as read-only memory. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20191214014710.3449601-4-andriin@fb.com
Diffstat (limited to '')
-rw-r--r--tools/lib/bpf/libbpf.c10
1 files changed, 5 insertions, 5 deletions
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 26144706ba0b..c9f90bfd2f0d 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -7472,7 +7472,8 @@ int bpf_object__open_skeleton(struct bpf_object_skeleton *s,
return -ESRCH;
}
- if (mmaped)
+ /* externs shouldn't be pre-setup from user code */
+ if (mmaped && (*map)->libbpf_type != LIBBPF_MAP_EXTERN)
*mmaped = (*map)->mmaped;
}
@@ -7505,7 +7506,6 @@ int bpf_object__load_skeleton(struct bpf_object_skeleton *s)
size_t mmap_sz = bpf_map_mmap_sz(map);
int prot, map_fd = bpf_map__fd(map);
void **mmaped = s->maps[i].mmaped;
- void *remapped;
if (!mmaped)
continue;
@@ -7530,9 +7530,9 @@ int bpf_object__load_skeleton(struct bpf_object_skeleton *s)
* as per normal clean up procedure, so we don't need to worry
* about it from skeleton's clean up perspective.
*/
- remapped = mmap(*mmaped, mmap_sz, prot, MAP_SHARED | MAP_FIXED,
- map_fd, 0);
- if (remapped == MAP_FAILED) {
+ *mmaped = mmap(map->mmaped, mmap_sz, prot,
+ MAP_SHARED | MAP_FIXED, map_fd, 0);
+ if (*mmaped == MAP_FAILED) {
err = -errno;
*mmaped = NULL;
pr_warn("failed to re-mmap() map '%s': %d\n",