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authorGravatar Jérôme Pouiller <jezz@sysmic.org>2016-12-20 14:46:18 +0100
committerGravatar Peter Korsgaard <peter@korsgaard.com>2017-02-07 21:45:01 +0100
commit76838f63412a30a358210e457dda4b79f7730624 (patch)
tree5aedfd22c554ac89916fcd73c62186c74afe9eb9
parentd3760efa7b92da74c39f5673c591b4fa14886b76 (diff)
downloadbuildroot-76838f63412a30a358210e457dda4b79f7730624.tar.gz
buildroot-76838f63412a30a358210e457dda4b79f7730624.tar.bz2
reproducible: fix DATE/TIME macros in toolchain-wrapper
The use of the __DATE__ and __TIME__ macros are one of the most common sources of non-reproducible binaries. In order to fix that, gcc 7 supports the SOURCE_DATE_EPOCH variable: https://gcc.gnu.org/git/?p=gcc.git;a=commitdiff;h=e3e8c48c4a494d9da741c1c8ea6c4c0b7c4ff934 This patch take advantage of toolchain-wrapper to provide support of SOURCE_DATE_EPOCH to older gcc versions. Function get_source_date_epoch() come directly from gcc git. This work was sponsored by `BA Robotic Systems'. [Peter: use sizeof for character array sizes, make function static, extend commit message, add upstream gcc commit] Signed-off-by: Jérôme Pouiller <jezz@sysmic.org> Reviewed-by: Samuel Martin <s.martin49@gmail.com> Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
-rw-r--r--toolchain/toolchain-wrapper.c72
1 files changed, 71 insertions, 1 deletions
diff --git a/toolchain/toolchain-wrapper.c b/toolchain/toolchain-wrapper.c
index 100aa181c6..eb4ee8de4a 100644
--- a/toolchain/toolchain-wrapper.c
+++ b/toolchain/toolchain-wrapper.c
@@ -22,12 +22,15 @@
#include <unistd.h>
#include <stdlib.h>
#include <errno.h>
+#include <time.h>
#ifdef BR_CCACHE
static char ccache_path[PATH_MAX];
#endif
static char path[PATH_MAX];
static char sysroot[PATH_MAX];
+static char source_time[sizeof("-D__TIME__=\"HH:MM:SS\"")];
+static char source_date[sizeof("-D__DATE__=\"MMM DD YYYY\"")];
/**
* GCC errors out with certain combinations of arguments (examples are
@@ -39,8 +42,11 @@ static char sysroot[PATH_MAX];
* -mfloat-abi=
* -march=
* -mcpu=
+ * -D__TIME__=
+ * -D__DATE__=
+ * -Wno-builtin-macro-redefined
*/
-#define EXCLUSIVE_ARGS 3
+#define EXCLUSIVE_ARGS 6
static char *predef_args[] = {
#ifdef BR_CCACHE
@@ -157,6 +163,47 @@ static void check_unsafe_path(const char *arg,
}
}
+/* Read SOURCE_DATE_EPOCH from environment to have a deterministic
+ * timestamp to replace embedded current dates to get reproducible
+ * results. Returns -1 if SOURCE_DATE_EPOCH is not defined.
+ */
+static time_t get_source_date_epoch()
+{
+ char *source_date_epoch;
+ long long epoch;
+ char *endptr;
+
+ source_date_epoch = getenv("SOURCE_DATE_EPOCH");
+ if (!source_date_epoch)
+ return (time_t) -1;
+
+ errno = 0;
+ epoch = strtoll(source_date_epoch, &endptr, 10);
+ if ((errno == ERANGE && (epoch == LLONG_MAX || epoch == LLONG_MIN))
+ || (errno != 0 && epoch == 0)) {
+ fprintf(stderr, "environment variable $SOURCE_DATE_EPOCH: "
+ "strtoll: %s\n", strerror(errno));
+ exit(2);
+ }
+ if (endptr == source_date_epoch) {
+ fprintf(stderr, "environment variable $SOURCE_DATE_EPOCH: "
+ "no digits were found: %s\n", endptr);
+ exit(2);
+ }
+ if (*endptr != '\0') {
+ fprintf(stderr, "environment variable $SOURCE_DATE_EPOCH: "
+ "trailing garbage: %s\n", endptr);
+ exit(2);
+ }
+ if (epoch < 0) {
+ fprintf(stderr, "environment variable $SOURCE_DATE_EPOCH: "
+ "value must be nonnegative: %lld \n", epoch);
+ exit(2);
+ }
+
+ return (time_t) epoch;
+}
+
int main(int argc, char **argv)
{
char **args, **cur, **exec_args;
@@ -167,6 +214,7 @@ int main(int argc, char **argv)
char *paranoid_wrapper;
int paranoid;
int ret, i, count = 0, debug;
+ time_t source_date_epoch;
/* Calculate the relative paths */
basename = strrchr(progpath, '/');
@@ -272,6 +320,28 @@ int main(int argc, char **argv)
}
#endif /* ARCH || CPU */
+ source_date_epoch = get_source_date_epoch();
+ if (source_date_epoch != -1) {
+ struct tm *tm = localtime(&source_date_epoch);
+ if (!tm) {
+ perror("__FILE__: localtime");
+ return 3;
+ }
+ ret = strftime(source_time, sizeof(source_time), "-D__TIME__=\"%T\"", tm);
+ if (!ret) {
+ perror("__FILE__: overflow");
+ return 3;
+ }
+ *cur++ = source_time;
+ ret = strftime(source_date, sizeof(source_date), "-D__DATE__=\"%b %e %Y\"", tm);
+ if (!ret) {
+ perror("__FILE__: overflow");
+ return 3;
+ }
+ *cur++ = source_date;
+ *cur++ = "-Wno-builtin-macro-redefined";
+ }
+
paranoid_wrapper = getenv("BR_COMPILER_PARANOID_UNSAFE_PATH");
if (paranoid_wrapper && strlen(paranoid_wrapper) > 0)
paranoid = 1;