From: Andrii Nakryiko <andriin@fb.com>
To: <andrii.nakryiko@gmail.com>, <ast@fb.com>, <daniel@iogearbox.net>,
<netdev@vger.kernel.org>, <bpf@vger.kernel.org>,
<kernel-team@fb.com>
Cc: Andrii Nakryiko <andriin@fb.com>
Subject: [PATCH v2 bpf-next 03/11] libbpf: streamline ELF parsing error-handling
Date: Mon, 17 Jun 2019 12:26:52 -0700 [thread overview]
Message-ID: <20190617192700.2313445-4-andriin@fb.com> (raw)
In-Reply-To: <20190617192700.2313445-1-andriin@fb.com>
Simplify ELF parsing logic by exiting early, as there is no common clean
up path to execute. That makes it unnecessary to track when err was set
and when it was cleared. It also reduces nesting in some places.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
---
tools/lib/bpf/libbpf.c | 44 +++++++++++++++++++-----------------------
1 file changed, 20 insertions(+), 24 deletions(-)
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 49d3a808e754..7ee44d8877c5 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -1154,24 +1154,21 @@ static int bpf_object__elf_collect(struct bpf_object *obj, int flags)
if (gelf_getshdr(scn, &sh) != &sh) {
pr_warning("failed to get section(%d) header from %s\n",
idx, obj->path);
- err = -LIBBPF_ERRNO__FORMAT;
- goto out;
+ return -LIBBPF_ERRNO__FORMAT;
}
name = elf_strptr(elf, ep->e_shstrndx, sh.sh_name);
if (!name) {
pr_warning("failed to get section(%d) name from %s\n",
idx, obj->path);
- err = -LIBBPF_ERRNO__FORMAT;
- goto out;
+ return -LIBBPF_ERRNO__FORMAT;
}
data = elf_getdata(scn, 0);
if (!data) {
pr_warning("failed to get section(%d) data from %s(%s)\n",
idx, name, obj->path);
- err = -LIBBPF_ERRNO__FORMAT;
- goto out;
+ return -LIBBPF_ERRNO__FORMAT;
}
pr_debug("section(%d) %s, size %ld, link %d, flags %lx, type=%d\n",
idx, name, (unsigned long)data->d_size,
@@ -1182,10 +1179,14 @@ static int bpf_object__elf_collect(struct bpf_object *obj, int flags)
err = bpf_object__init_license(obj,
data->d_buf,
data->d_size);
+ if (err)
+ return err;
} else if (strcmp(name, "version") == 0) {
err = bpf_object__init_kversion(obj,
data->d_buf,
data->d_size);
+ if (err)
+ return err;
} else if (strcmp(name, "maps") == 0) {
obj->efile.maps_shndx = idx;
} else if (strcmp(name, BTF_ELF_SEC) == 0) {
@@ -1196,11 +1197,10 @@ static int bpf_object__elf_collect(struct bpf_object *obj, int flags)
if (obj->efile.symbols) {
pr_warning("bpf: multiple SYMTAB in %s\n",
obj->path);
- err = -LIBBPF_ERRNO__FORMAT;
- } else {
- obj->efile.symbols = data;
- obj->efile.strtabidx = sh.sh_link;
+ return -LIBBPF_ERRNO__FORMAT;
}
+ obj->efile.symbols = data;
+ obj->efile.strtabidx = sh.sh_link;
} else if (sh.sh_type == SHT_PROGBITS && data->d_size > 0) {
if (sh.sh_flags & SHF_EXECINSTR) {
if (strcmp(name, ".text") == 0)
@@ -1214,6 +1214,7 @@ static int bpf_object__elf_collect(struct bpf_object *obj, int flags)
pr_warning("failed to alloc program %s (%s): %s",
name, obj->path, cp);
+ return err;
}
} else if (strcmp(name, ".data") == 0) {
obj->efile.data = data;
@@ -1225,8 +1226,8 @@ static int bpf_object__elf_collect(struct bpf_object *obj, int flags)
pr_debug("skip section(%d) %s\n", idx, name);
}
} else if (sh.sh_type == SHT_REL) {
+ int nr_reloc = obj->efile.nr_reloc;
void *reloc = obj->efile.reloc;
- int nr_reloc = obj->efile.nr_reloc + 1;
int sec = sh.sh_info; /* points to other section */
/* Only do relo for section with exec instructions */
@@ -1236,28 +1237,24 @@ static int bpf_object__elf_collect(struct bpf_object *obj, int flags)
continue;
}
- reloc = reallocarray(reloc, nr_reloc,
+ reloc = reallocarray(reloc, nr_reloc + 1,
sizeof(*obj->efile.reloc));
if (!reloc) {
pr_warning("realloc failed\n");
- err = -ENOMEM;
- } else {
- int n = nr_reloc - 1;
+ return -ENOMEM;
+ }
- obj->efile.reloc = reloc;
- obj->efile.nr_reloc = nr_reloc;
+ obj->efile.reloc = reloc;
+ obj->efile.nr_reloc++;
- obj->efile.reloc[n].shdr = sh;
- obj->efile.reloc[n].data = data;
- }
+ obj->efile.reloc[nr_reloc].shdr = sh;
+ obj->efile.reloc[nr_reloc].data = data;
} else if (sh.sh_type == SHT_NOBITS && strcmp(name, ".bss") == 0) {
obj->efile.bss = data;
obj->efile.bss_shndx = idx;
} else {
pr_debug("skip section(%d) %s\n", idx, name);
}
- if (err)
- goto out;
}
if (!obj->efile.strtabidx || obj->efile.strtabidx >= idx) {
@@ -1270,10 +1267,9 @@ static int bpf_object__elf_collect(struct bpf_object *obj, int flags)
if (bpf_object__has_maps(obj)) {
err = bpf_object__init_maps(obj, flags);
if (err)
- goto out;
+ return err;
}
err = bpf_object__init_prog_names(obj);
-out:
return err;
}
--
2.17.1
next prev parent reply other threads:[~2019-06-17 19:27 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-17 19:26 [PATCH v2 bpf-next 00/11] BTF-defined BPF map definitions Andrii Nakryiko
2019-06-17 19:26 ` [PATCH v2 bpf-next 01/11] libbpf: add common min/max macro to libbpf_internal.h Andrii Nakryiko
2019-06-17 19:26 ` [PATCH v2 bpf-next 02/11] libbpf: extract BTF loading logic Andrii Nakryiko
2019-06-17 19:40 ` Song Liu
2019-06-17 19:26 ` Andrii Nakryiko [this message]
2019-06-17 19:46 ` [PATCH v2 bpf-next 03/11] libbpf: streamline ELF parsing error-handling Song Liu
2019-06-17 19:26 ` [PATCH v2 bpf-next 04/11] libbpf: refactor map initialization Andrii Nakryiko
2019-06-17 19:39 ` Song Liu
2019-06-26 14:48 ` Matt Hart
2019-06-26 18:28 ` Andrii Nakryiko
2019-06-27 15:11 ` Matt Hart
2019-06-17 19:26 ` [PATCH v2 bpf-next 05/11] libbpf: identify maps by section index in addition to offset Andrii Nakryiko
2019-06-17 19:26 ` [PATCH v2 bpf-next 06/11] libbpf: split initialization and loading of BTF Andrii Nakryiko
2019-06-17 19:26 ` [PATCH v2 bpf-next 07/11] libbpf: allow specifying map definitions using BTF Andrii Nakryiko
2019-06-17 19:43 ` Song Liu
2019-06-17 19:26 ` [PATCH v2 bpf-next 08/11] selftests/bpf: add test for BTF-defined maps Andrii Nakryiko
2019-06-17 19:26 ` [PATCH v2 bpf-next 09/11] selftests/bpf: switch BPF_ANNOTATE_KV_PAIR tests to " Andrii Nakryiko
2019-06-17 21:41 ` Song Liu
2019-06-17 22:20 ` Daniel Borkmann
2019-06-17 19:26 ` [PATCH v2 bpf-next 10/11] selftests/bpf: convert tests w/ custom values " Andrii Nakryiko
2019-06-17 19:27 ` [PATCH v2 bpf-next 11/11] selftests/bpf: convert remaining selftests " Andrii Nakryiko
2019-06-17 21:17 ` [PATCH v2 bpf-next 00/11] BTF-defined BPF map definitions Daniel Borkmann
2019-06-17 22:17 ` Daniel Borkmann
2019-06-18 21:37 ` Andrii Nakryiko
2019-06-20 14:49 ` Lorenz Bauer
2019-06-21 4:19 ` Andrii Nakryiko
2019-06-21 10:29 ` Lorenz Bauer
2019-06-21 17:56 ` Andrii Nakryiko
2019-06-25 18:14 ` Andrii Nakryiko
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