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authorPeter Wu <peter@lekensteyn.nl>2019-08-09 03:39:11 +0300
committerDaniel Borkmann <daniel@iogearbox.net>2019-08-12 12:07:16 +0300
commita664a834579ae8a6166ac9e5a3232976cab2c24d (patch)
tree297da431ae1c5022c9fc104033d0fcd6ed4d6d51 /tools
parent9f30cd568b392051e0dcfa69b7f8d6021b41ed2a (diff)
downloadlinux-a664a834579ae8a6166ac9e5a3232976cab2c24d.tar.xz
tools: bpftool: fix reading from /proc/config.gz
/proc/config has never existed as far as I can see, but /proc/config.gz is present on Arch Linux. Add support for decompressing config.gz using zlib which is a mandatory dependency of libelf anyway. Replace existing stdio functions with gzFile operations since the latter transparently handles uncompressed and gzip-compressed files. Cc: Quentin Monnet <quentin.monnet@netronome.com> Signed-off-by: Peter Wu <peter@lekensteyn.nl> Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Diffstat (limited to 'tools')
-rw-r--r--tools/bpf/bpftool/Makefile2
-rw-r--r--tools/bpf/bpftool/feature.c105
2 files changed, 54 insertions, 53 deletions
diff --git a/tools/bpf/bpftool/Makefile b/tools/bpf/bpftool/Makefile
index a7afea4dec47..078bd0dcfba5 100644
--- a/tools/bpf/bpftool/Makefile
+++ b/tools/bpf/bpftool/Makefile
@@ -52,7 +52,7 @@ ifneq ($(EXTRA_LDFLAGS),)
LDFLAGS += $(EXTRA_LDFLAGS)
endif
-LIBS = -lelf $(LIBBPF)
+LIBS = -lelf -lz $(LIBBPF)
INSTALL ?= install
RM ?= rm -f
diff --git a/tools/bpf/bpftool/feature.c b/tools/bpf/bpftool/feature.c
index d672d9086fff..03bdc5b3ac49 100644
--- a/tools/bpf/bpftool/feature.c
+++ b/tools/bpf/bpftool/feature.c
@@ -14,6 +14,7 @@
#include <bpf.h>
#include <libbpf.h>
+#include <zlib.h>
#include "main.h"
@@ -284,34 +285,32 @@ static void probe_jit_limit(void)
}
}
-static char *get_kernel_config_option(FILE *fd, const char *option)
+static bool read_next_kernel_config_option(gzFile file, char *buf, size_t n,
+ char **value)
{
- size_t line_n = 0, optlen = strlen(option);
- char *res, *strval, *line = NULL;
- ssize_t n;
+ char *sep;
- rewind(fd);
- while ((n = getline(&line, &line_n, fd)) > 0) {
- if (strncmp(line, option, optlen))
+ while (gzgets(file, buf, n)) {
+ if (strncmp(buf, "CONFIG_", 7))
continue;
- /* Check we have at least '=', value, and '\n' */
- if (strlen(line) < optlen + 3)
- continue;
- if (*(line + optlen) != '=')
+
+ sep = strchr(buf, '=');
+ if (!sep)
continue;
/* Trim ending '\n' */
- line[strlen(line) - 1] = '\0';
+ buf[strlen(buf) - 1] = '\0';
+
+ /* Split on '=' and ensure that a value is present. */
+ *sep = '\0';
+ if (!sep[1])
+ continue;
- /* Copy and return config option value */
- strval = line + optlen + 1;
- res = strdup(strval);
- free(line);
- return res;
+ *value = sep + 1;
+ return true;
}
- free(line);
- return NULL;
+ return false;
}
static void probe_kernel_image_config(void)
@@ -386,59 +385,61 @@ static void probe_kernel_image_config(void)
/* test_bpf module for BPF tests */
"CONFIG_TEST_BPF",
};
- char *value, *buf = NULL;
+ char *values[ARRAY_SIZE(options)] = { };
struct utsname utsn;
char path[PATH_MAX];
- size_t i, n;
- ssize_t ret;
- FILE *fd;
+ gzFile file = NULL;
+ char buf[4096];
+ char *value;
+ size_t i;
- if (uname(&utsn))
- goto no_config;
+ if (!uname(&utsn)) {
+ snprintf(path, sizeof(path), "/boot/config-%s", utsn.release);
- snprintf(path, sizeof(path), "/boot/config-%s", utsn.release);
+ /* gzopen also accepts uncompressed files. */
+ file = gzopen(path, "r");
+ }
- fd = fopen(path, "r");
- if (!fd && errno == ENOENT) {
- /* Some distributions put the config file at /proc/config, give
- * it a try.
- * Sometimes it is also at /proc/config.gz but we do not try
- * this one for now, it would require linking against libz.
+ if (!file) {
+ /* Some distributions build with CONFIG_IKCONFIG=y and put the
+ * config file at /proc/config.gz.
*/
- fd = fopen("/proc/config", "r");
+ file = gzopen("/proc/config.gz", "r");
}
- if (!fd) {
+ if (!file) {
p_info("skipping kernel config, can't open file: %s",
strerror(errno));
- goto no_config;
+ goto end_parse;
}
/* Sanity checks */
- ret = getline(&buf, &n, fd);
- ret = getline(&buf, &n, fd);
- if (!buf || !ret) {
+ if (!gzgets(file, buf, sizeof(buf)) ||
+ !gzgets(file, buf, sizeof(buf))) {
p_info("skipping kernel config, can't read from file: %s",
strerror(errno));
- free(buf);
- goto no_config;
+ goto end_parse;
}
if (strcmp(buf, "# Automatically generated file; DO NOT EDIT.\n")) {
p_info("skipping kernel config, can't find correct file");
- free(buf);
- goto no_config;
+ goto end_parse;
}
- free(buf);
- for (i = 0; i < ARRAY_SIZE(options); i++) {
- value = get_kernel_config_option(fd, options[i]);
- print_kernel_option(options[i], value);
- free(value);
+ while (read_next_kernel_config_option(file, buf, sizeof(buf), &value)) {
+ for (i = 0; i < ARRAY_SIZE(options); i++) {
+ if (values[i] || strcmp(buf, options[i]))
+ continue;
+
+ values[i] = strdup(value);
+ }
}
- fclose(fd);
- return;
-no_config:
- for (i = 0; i < ARRAY_SIZE(options); i++)
- print_kernel_option(options[i], NULL);
+end_parse:
+ if (file)
+ gzclose(file);
+
+ for (i = 0; i < ARRAY_SIZE(options); i++) {
+ print_kernel_option(options[i], values[i]);
+ free(values[i]);
+ }
}
static bool probe_bpf_syscall(const char *define_prefix)