@@ -1043,18 +1043,27 @@ void bpf_gen__map_update_elem(struct bpf_gen *gen, int map_idx, void *pvalue,
value = add_data(gen, pvalue, value_size);
key = add_data(gen, &zero, sizeof(zero));
- /* if (map_desc[map_idx].initial_value)
- * copy_from_user(value, initial_value, value_size);
+ /* if (map_desc[map_idx].initial_value) {
+ * if (ctx->flags & BPF_SKEL_KERNEL)
+ * bpf_probe_read_kernel(value, value_size, initial_value);
+ * else
+ * bpf_copy_from_user(value, value_size, initial_value);
+ * }
*/
emit(gen, BPF_LDX_MEM(BPF_DW, BPF_REG_3, BPF_REG_6,
sizeof(struct bpf_loader_ctx) +
sizeof(struct bpf_map_desc) * map_idx +
offsetof(struct bpf_map_desc, initial_value)));
- emit(gen, BPF_JMP_IMM(BPF_JEQ, BPF_REG_3, 0, 4));
+ emit(gen, BPF_JMP_IMM(BPF_JEQ, BPF_REG_3, 0, 8));
emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_1, BPF_PSEUDO_MAP_IDX_VALUE,
0, 0, 0, value));
emit(gen, BPF_MOV64_IMM(BPF_REG_2, value_size));
+ emit(gen, BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_6,
+ offsetof(struct bpf_loader_ctx, flags)));
+ emit(gen, BPF_JMP_IMM(BPF_JSET, BPF_REG_0, BPF_SKEL_KERNEL, 2));
emit(gen, BPF_EMIT_CALL(BPF_FUNC_copy_from_user));
+ emit(gen, BPF_JMP_IMM(BPF_JA, 0, 0, 1));
+ emit(gen, BPF_EMIT_CALL(BPF_FUNC_probe_read_kernel));
map_update_attr = add_data(gen, &attr, attr_size);
move_blob2blob(gen, attr_field(map_update_attr, map_fd), 4,
@@ -3,9 +3,19 @@
#ifndef __SKEL_INTERNAL_H
#define __SKEL_INTERNAL_H
+#ifdef __KERNEL__
+#include <linux/fdtable.h>
+#include <linux/mm.h>
+#include <linux/mman.h>
+#include <linux/slab.h>
+#include <linux/bpf.h>
+#else
#include <unistd.h>
#include <sys/syscall.h>
#include <sys/mman.h>
+#include <stdlib.h>
+#include "bpf.h"
+#endif
#ifndef __NR_bpf
# if defined(__mips__) && defined(_ABIO32)
@@ -25,24 +35,23 @@
* requested during loader program generation.
*/
struct bpf_map_desc {
- union {
- /* input for the loader prog */
- struct {
- __aligned_u64 initial_value;
- __u32 max_entries;
- };
- /* output of the loader prog */
- struct {
- int map_fd;
- };
- };
+ /* output of the loader prog */
+ int map_fd;
+ /* input for the loader prog */
+ __u32 max_entries;
+ __aligned_u64 initial_value;
};
struct bpf_prog_desc {
int prog_fd;
};
+enum {
+ BPF_SKEL_KERNEL = (1ULL << 0),
+};
+
struct bpf_loader_ctx {
- size_t sz;
+ __u32 sz;
+ __u32 flags;
__u32 log_level;
__u32 log_size;
__u64 log_buf;
@@ -57,12 +66,144 @@ struct bpf_load_and_run_opts {
const char *errstr;
};
+long bpf_sys_bpf(__u32 cmd, void *attr, __u32 attr_size);
+
static inline int skel_sys_bpf(enum bpf_cmd cmd, union bpf_attr *attr,
unsigned int size)
{
+#ifdef __KERNEL__
+ return bpf_sys_bpf(cmd, attr, size);
+#else
return syscall(__NR_bpf, cmd, attr, size);
+#endif
+}
+
+#ifdef __KERNEL__
+static inline int close(int fd)
+{
+ return close_fd(fd);
+}
+
+static inline void *skel_alloc(size_t size)
+{
+ struct bpf_loader_ctx *ctx = kzalloc(size, GFP_KERNEL);
+
+ if (!ctx)
+ return NULL;
+ ctx->flags |= BPF_SKEL_KERNEL;
+ return ctx;
+}
+
+static inline void skel_free(const void *p)
+{
+ kfree(p);
+}
+
+/* skel->bss/rodata maps are populated the following way:
+ *
+ * For kernel use:
+ * skel_prep_map_data() allocates kernel memory that kernel module can directly access.
+ * Generated lskel stores the pointer in skel->rodata and in skel->maps.rodata.initial_value.
+ * The loader program will perform probe_read_kernel() from maps.rodata.initial_value.
+ * skel_finalize_map_data() sets skel->rodata to point to actual value in a bpf map and
+ * does maps.rodata.initial_value = ~0ULL to signal skel_free_map_data() that kvfree
+ * is not nessary.
+ *
+ * For user space:
+ * skel_prep_map_data() mmaps anon memory into skel->rodata that can be accessed directly.
+ * Generated lskel stores the pointer in skel->rodata and in skel->maps.rodata.initial_value.
+ * The loader program will perform copy_from_user() from maps.rodata.initial_value.
+ * skel_finalize_map_data() remaps bpf array map value from the kernel memory into
+ * skel->rodata address.
+ *
+ * The "bpftool gen skeleton -L" command generates lskel.h that is suitable for
+ * both kernel and user space. The generated loader program does
+ * either bpf_probe_read_kernel() or bpf_copy_from_user() from initial_value
+ * depending on bpf_loader_ctx->flags.
+ */
+static inline void skel_free_map_data(void *p, __u64 addr, size_t sz)
+{
+ if (addr != ~0ULL)
+ kvfree(p);
+ /* When addr == ~0ULL the 'p' points to
+ * ((struct bpf_array *)map)->value. See skel_finalize_map_data.
+ */
}
+static inline void *skel_prep_map_data(const void *val, size_t mmap_sz, size_t val_sz)
+{
+ void *addr;
+
+ addr = kvmalloc(val_sz, GFP_KERNEL);
+ if (!addr)
+ return NULL;
+ memcpy(addr, val, val_sz);
+ return addr;
+}
+
+static inline void *skel_finalize_map_data(__u64 *init_val, size_t mmap_sz, int flags, int fd)
+{
+ struct bpf_map *map;
+ void *addr = NULL;
+
+ kvfree((void *) (long) *init_val);
+ *init_val = ~0ULL;
+
+ /* At this point bpf_load_and_run() finished without error and
+ * 'fd' is a valid bpf map FD. All sanity checks below should succeed.
+ */
+ map = bpf_map_get(fd);
+ if (IS_ERR(map))
+ return NULL;
+ if (map->map_type != BPF_MAP_TYPE_ARRAY)
+ goto out;
+ addr = ((struct bpf_array *)map)->value;
+ /* the addr stays valid, since FD is not closed */
+out:
+ bpf_map_put(map);
+ return addr;
+}
+
+#else
+
+static inline void *skel_alloc(size_t size)
+{
+ return calloc(1, size);
+}
+
+static inline void skel_free(void *p)
+{
+ free(p);
+}
+
+static inline void skel_free_map_data(void *p, __u64 addr, size_t sz)
+{
+ munmap(p, sz);
+}
+
+static inline void *skel_prep_map_data(const void *val, size_t mmap_sz, size_t val_sz)
+{
+ void *addr;
+
+ addr = mmap(NULL, mmap_sz, PROT_READ | PROT_WRITE,
+ MAP_SHARED | MAP_ANONYMOUS, -1, 0);
+ if (addr == (void *) -1)
+ return NULL;
+ memcpy(addr, val, val_sz);
+ return addr;
+}
+
+static inline void *skel_finalize_map_data(__u64 *init_val, size_t mmap_sz, int flags, int fd)
+{
+ void *addr;
+
+ addr = mmap((void *) (long) *init_val, mmap_sz, flags, MAP_SHARED | MAP_FIXED, fd, 0);
+ if (addr == (void *) -1)
+ return NULL;
+ return addr;
+}
+#endif
+
static inline int skel_closenz(int fd)
{
if (fd > 0)
@@ -136,22 +277,28 @@ static inline int skel_link_create(int prog_fd, int target_fd,
return skel_sys_bpf(BPF_LINK_CREATE, &attr, attr_sz);
}
+#ifdef __KERNEL__
+#define set_err
+#else
+#define set_err err = -errno
+#endif
+
static inline int bpf_load_and_run(struct bpf_load_and_run_opts *opts)
{
int map_fd = -1, prog_fd = -1, key = 0, err;
union bpf_attr attr;
- map_fd = skel_map_create(BPF_MAP_TYPE_ARRAY, "__loader.map", 4, opts->data_sz, 1);
+ err = map_fd = skel_map_create(BPF_MAP_TYPE_ARRAY, "__loader.map", 4, opts->data_sz, 1);
if (map_fd < 0) {
opts->errstr = "failed to create loader map";
- err = -errno;
+ set_err;
goto out;
}
err = skel_map_update_elem(map_fd, &key, opts->data, 0);
if (err < 0) {
opts->errstr = "failed to update loader map";
- err = -errno;
+ set_err;
goto out;
}
@@ -166,10 +313,10 @@ static inline int bpf_load_and_run(struct bpf_load_and_run_opts *opts)
attr.log_size = opts->ctx->log_size;
attr.log_buf = opts->ctx->log_buf;
attr.prog_flags = BPF_F_SLEEPABLE;
- prog_fd = skel_sys_bpf(BPF_PROG_LOAD, &attr, sizeof(attr));
+ err = prog_fd = skel_sys_bpf(BPF_PROG_LOAD, &attr, sizeof(attr));
if (prog_fd < 0) {
opts->errstr = "failed to load loader prog";
- err = -errno;
+ set_err;
goto out;
}
@@ -181,10 +328,12 @@ static inline int bpf_load_and_run(struct bpf_load_and_run_opts *opts)
if (err < 0 || (int)attr.test.retval < 0) {
opts->errstr = "failed to execute loader prog";
if (err < 0) {
- err = -errno;
+ set_err;
} else {
err = (int)attr.test.retval;
+#ifndef __KERNEL__
errno = -err;
+#endif
}
goto out;
}