From: Wang Nan <wangnan0@huawei.com>
To: <acme@kernel.org>, <ast@plumgrid.com>,
<brendan.d.gregg@gmail.com>, <daniel@iogearbox.net>,
<namhyung@kernel.org>, <masami.hiramatsu.pt@hitachi.com>,
<paulus@samba.org>, <a.p.zijlstra@chello.nl>, <mingo@redhat.com>,
<jolsa@kernel.org>, <dsahern@gmail.com>
Cc: <linux-kernel@vger.kernel.org>, <lizefan@huawei.com>,
<hekuang@huawei.com>, <xiakaixu@huawei.com>, <pi3orama@163.com>
Subject: [RFC PATCH v6 05/32] bpf tools: Read eBPF object from buffer
Date: Tue, 9 Jun 2015 05:50:09 +0000 [thread overview]
Message-ID: <1433829036-23687-6-git-send-email-wangnan0@huawei.com> (raw)
In-Reply-To: <1433829036-23687-1-git-send-email-wangnan0@huawei.com>
To support dynamic compiling, this patch allows caller to pass a
in-memory buffer to libbpf by bpf_object__open_buffer(). libbpf
calls elf_memory() to open it as ELF object file.
Because __bpf_object__open() collects all required data and won't need
that buffer anymore, libbpf uses that buffer directly instead of clone
a new buffer. Caller of libbpf can free that buffer or use it do other
things after bpf_object__open_buffer() return.
Signed-off-by: Wang Nan <wangnan0@huawei.com>
---
tools/lib/bpf/libbpf.c | 62 ++++++++++++++++++++++++++++++++++++++++----------
tools/lib/bpf/libbpf.h | 2 ++
2 files changed, 52 insertions(+), 12 deletions(-)
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 197ab5e..8ba6ac6 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -84,6 +84,8 @@ struct bpf_object {
*/
struct {
int fd;
+ void *obj_buf;
+ size_t obj_buf_sz;
Elf *elf;
GElf_Ehdr ehdr;
} efile;
@@ -91,7 +93,9 @@ struct bpf_object {
};
#define obj_elf_valid(o) ((o)->efile.elf)
-static struct bpf_object *bpf_object__new(const char *path)
+static struct bpf_object *bpf_object__new(const char *path,
+ void *obj_buf,
+ size_t obj_buf_sz)
{
struct bpf_object *obj;
@@ -103,6 +107,16 @@ static struct bpf_object *bpf_object__new(const char *path)
strcpy(obj->path, path);
obj->efile.fd = -1;
+
+ /*
+ * Caller of this function should also calls
+ * bpf_object__elf_finish() after data collection to return
+ * obj_buf to user. If not, we should duplicate the buffer to
+ * avoid user freeing them before elf finish.
+ */
+ obj->efile.obj_buf = obj_buf;
+ obj->efile.obj_buf_sz = obj_buf_sz;
+
return obj;
}
@@ -116,6 +130,8 @@ static void bpf_object__elf_finish(struct bpf_object *obj)
obj->efile.elf = NULL;
}
zclose(obj->efile.fd);
+ obj->efile.obj_buf = NULL;
+ obj->efile.obj_buf_sz = 0;
}
static int bpf_object__elf_init(struct bpf_object *obj)
@@ -128,16 +144,26 @@ static int bpf_object__elf_init(struct bpf_object *obj)
return -EEXIST;
}
- 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));
- return -errno;
+ if (obj->efile.obj_buf_sz > 0) {
+ /*
+ * obj_buf should have been validated by
+ * bpf_object__open_buffer().
+ */
+ obj->efile.elf = elf_memory(obj->efile.obj_buf,
+ obj->efile.obj_buf_sz);
+ } 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));
+ return -errno;
+ }
+
+ obj->efile.elf = elf_begin(obj->efile.fd,
+ LIBBPF_ELF_C_READ_MMAP,
+ NULL);
}
- obj->efile.elf = elf_begin(obj->efile.fd,
- LIBBPF_ELF_C_READ_MMAP,
- NULL);
if (!obj->efile.elf) {
pr_warning("failed to open %s as ELF file\n",
obj->path);
@@ -167,7 +193,7 @@ errout:
}
static struct bpf_object *
-__bpf_object__open(const char *path)
+__bpf_object__open(const char *path, void *obj_buf, size_t obj_buf_sz)
{
struct bpf_object *obj;
@@ -176,7 +202,7 @@ __bpf_object__open(const char *path)
return NULL;
}
- obj = bpf_object__new(path);
+ obj = bpf_object__new(path, obj_buf, obj_buf_sz);
if (!obj)
return NULL;
@@ -198,7 +224,19 @@ struct bpf_object *bpf_object__open(const char *path)
pr_debug("loading %s\n", path);
- return __bpf_object__open(path);
+ return __bpf_object__open(path, NULL, 0);
+}
+
+struct bpf_object *bpf_object__open_buffer(void *obj_buf,
+ size_t obj_buf_sz)
+{
+ /* param validation */
+ if (!obj_buf || obj_buf_sz <= 0)
+ return NULL;
+
+ pr_debug("loading object from buffer\n");
+
+ return __bpf_object__open("[buffer]", obj_buf, obj_buf_sz);
}
void bpf_object__close(struct bpf_object *obj)
diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
index ec3301c..dc966dd 100644
--- a/tools/lib/bpf/libbpf.h
+++ b/tools/lib/bpf/libbpf.h
@@ -26,6 +26,8 @@ void libbpf_set_print(libbpf_print_fn_t warn,
struct bpf_object;
struct bpf_object *bpf_object__open(const char *path);
+struct bpf_object *bpf_object__open_buffer(void *obj_buf,
+ size_t obj_buf_sz);
void bpf_object__close(struct bpf_object *object);
#endif
--
1.8.3.4
next prev parent reply other threads:[~2015-06-09 5:59 UTC|newest]
Thread overview: 58+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-06-09 5:50 [RFC PATCH v6 00/32] perf tools: filtering events using eBPF programs Wang Nan
2015-06-09 5:50 ` [RFC PATCH v6 01/32] tools build: Add feature check for eBPF API Wang Nan
2015-06-09 5:50 ` [RFC PATCH v6 02/32] bpf tools: Introduce 'bpf' library to tools Wang Nan
2015-06-09 5:50 ` [RFC PATCH v6 03/32] bpf tools: Allow caller to set printing function Wang Nan
2015-06-09 5:50 ` [RFC PATCH v6 04/32] bpf tools: Open eBPF object file and do basic validation Wang Nan
2015-06-09 5:50 ` Wang Nan [this message]
2015-06-09 5:50 ` [RFC PATCH v6 06/32] bpf tools: Check endianess and make libbpf fail early Wang Nan
2015-06-09 5:50 ` [RFC PATCH v6 07/32] bpf tools: Iterate over ELF sections to collect information Wang Nan
2015-06-09 5:50 ` [RFC PATCH v6 08/32] bpf tools: Collect version and license from ELF sections Wang Nan
2015-06-09 5:50 ` [RFC PATCH v6 09/32] bpf tools: Collect map definitions from 'maps' section Wang Nan
2015-06-09 5:50 ` [RFC PATCH v6 10/32] bpf tools: Collect symbol table from SHT_SYMTAB section Wang Nan
2015-06-09 5:50 ` [RFC PATCH v6 11/32] bpf tools: Collect eBPF programs from their own sections Wang Nan
2015-06-09 5:50 ` [RFC PATCH v6 12/32] bpf tools: Collect relocation sections from SHT_REL sections Wang Nan
2015-06-09 5:50 ` [RFC PATCH v6 13/32] bpf tools: Record map accessing instructions for each program Wang Nan
2015-06-09 5:50 ` [RFC PATCH v6 14/32] bpf tools: Add bpf.c/h for common bpf operations Wang Nan
2015-06-09 5:50 ` [RFC PATCH v6 15/32] bpf tools: Create eBPF maps defined in an object file Wang Nan
2015-06-09 5:50 ` [RFC PATCH v6 16/32] bpf tools: Relocate eBPF programs Wang Nan
2015-06-09 5:50 ` [RFC PATCH v6 17/32] bpf tools: Introduce bpf_load_program() to bpf.c Wang Nan
2015-06-09 5:50 ` [RFC PATCH v6 18/32] bpf tools: Load eBPF programs in object files into kernel Wang Nan
2015-06-09 5:50 ` [RFC PATCH v6 19/32] bpf tools: Introduce accessors for struct bpf_program Wang Nan
2015-06-09 5:50 ` [RFC PATCH v6 20/32] bpf tools: Introduce accessors for struct bpf_object Wang Nan
2015-06-09 5:50 ` [RFC PATCH v6 21/32] bpf tools: Link all bpf objects onto a list Wang Nan
2015-06-09 5:50 ` [RFC PATCH v6 22/32] perf tools: Make perf depend on libbpf Wang Nan
2015-06-09 10:29 ` Wangnan (F)
2015-06-09 5:50 ` [RFC PATCH v6 23/32] perf record: Enable passing bpf object file to --event Wang Nan
2015-06-09 5:50 ` [RFC PATCH v6 24/32] perf record: Compile scriptlets if pass '.c' " Wang Nan
2015-06-09 21:48 ` Alexei Starovoitov
2015-06-10 0:06 ` Wangnan (F)
2015-06-10 0:28 ` Alexei Starovoitov
2015-06-11 7:19 ` Namhyung Kim
2015-06-11 7:35 ` Wangnan (F)
2015-06-11 17:42 ` Alexei Starovoitov
2015-06-09 5:50 ` [RFC PATCH v6 25/32] perf tools: Add 'bpf.' config section to perf default config Wang Nan
2015-06-09 23:43 ` Alexei Starovoitov
2015-06-10 0:47 ` Wangnan (F)
2015-06-10 1:09 ` Alexei Starovoitov
2015-06-10 2:23 ` Wangnan (F)
2015-06-10 3:55 ` Alexei Starovoitov
2015-06-11 7:45 ` Namhyung Kim
2015-06-11 8:09 ` Wangnan (F)
2015-06-11 14:50 ` Namhyung Kim
2015-06-09 5:50 ` [RFC PATCH v6 26/32] perf tools: Parse probe points of eBPF programs during preparation Wang Nan
2015-06-09 5:50 ` [RFC PATCH v6 27/32] perf probe: Attach trace_probe_event with perf_probe_event Wang Nan
2015-06-09 5:50 ` [RFC PATCH v6 28/32] perf record: Probe at kprobe points Wang Nan
2015-06-11 14:32 ` Namhyung Kim
2015-06-09 5:50 ` [RFC PATCH v6 29/32] perf record: Load all eBPF object into kernel Wang Nan
2015-06-09 5:50 ` [RFC PATCH v6 30/32] perf tools: Add bpf_fd field to evsel and config it Wang Nan
2015-06-09 5:50 ` [RFC PATCH v6 31/32] perf tools: Attach eBPF program to perf event Wang Nan
2015-06-09 5:50 ` [RFC PATCH v6 32/32] perf record: Add LLVM options for compiling BPF scripts Wang Nan
2015-06-09 13:32 ` Wangnan (F)
2015-06-10 0:02 ` Alexei Starovoitov
2015-06-10 0:17 ` Wangnan (F)
2015-06-10 1:34 ` Alexei Starovoitov
2015-06-09 13:59 ` [RFC PATCH v6 00/32] perf tools: filtering events using eBPF programs Arnaldo Carvalho de Melo
2015-06-09 23:45 ` Wangnan (F)
2015-06-09 21:30 ` Alexei Starovoitov
2015-06-09 21:44 ` Arnaldo Carvalho de Melo
2015-06-09 23:16 ` Alexei Starovoitov
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