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reproducible: fix DATE/TIME macros in toolchain-wrapper

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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>
This commit is contained in:
Jérôme Pouiller 2016-12-20 14:46:18 +01:00 committed by Peter Korsgaard
parent d3760efa7b
commit 76838f6341
1 changed files with 71 additions and 1 deletions
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72
toolchain/toolchain-wrapper.c
View File

@ -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;