kumquat-buildroot/toolchain/toolchain-wrapper.c
Yann E. MORIN 6393b6904b toolchain/wrapper: fake __DATE_ and __TIME__ for older gcc
Starting with version 7, gcc automatically recognises and enforces the
environment variable SOURCE_DATE_EPOCH, and fakes __DATE__ and __TIME__
accordingly, to produce reproducible builds (at least in regards to date
and time).

However, older gcc versions do not offer this feature.

So, we use our toolchain wrapper to force-feed __DATE__ and __TIME__ as
macros, which will take precedence over those that gcc may compute
itself. We compute them according to the specs:
    https://reproducible-builds.org/specs/source-date-epoch/
    https://gcc.gnu.org/onlinedocs/cpp/Standard-Predefined-Macros.html

Since we define macros otherwise internal to gcc, we have to tell it not
to warn about that. The -Wno-builtin-macro-redefined flag was introduced
in gcc-4.4.0. Therefore, we make BR2_REPRODUCIBLE depend on GCC >= 4.4.

gcc-7 will ignore SOURCE_DATE_EPOCH when __DATE__ and __TIME__ are
user-defined. Anyway, this is of no consequence: whether __DATE__ and
__TIME__ or SOURCE_DATE_EPOCH takes precedence, it would yield the
exact same end result since we use the same logic to compute it. Note
that we didn't copy the code for it from gcc so using the same logic
doesn't imply that we're inheriting GPL-3.0.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Cc: Jérôme Pouiller <jezz@sysmic.org>
Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Cc: Arnout Vandecappelle <arnout@mind.be>
Cc: Peter Korsgaard <peter@korsgaard.com>
[Arnout: rewrite commit message]
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
Reviewed-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
2017-10-22 16:10:37 +02:00

452 lines
12 KiB
C

/**
* Buildroot wrapper for toolchains. This simply executes the real toolchain
* with a number of arguments (sysroot/arch/..) hardcoded, to ensure the
* toolchain uses the correct configuration.
* The hardcoded path arguments are defined relative to the actual location
* of the binary.
*
* (C) 2011 Peter Korsgaard <jacmet@sunsite.dk>
* (C) 2011 Daniel Nyström <daniel.nystrom@timeterminal.se>
* (C) 2012 Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
* (C) 2013 Spenser Gilliland <spenser@gillilanding.com>
*
* This file is licensed under the terms of the GNU General Public License
* version 2. This program is licensed "as is" without any warranty of any
* kind, whether express or implied.
*/
#define _GNU_SOURCE
#include <stdio.h>
#include <string.h>
#include <limits.h>
#include <unistd.h>
#include <stdlib.h>
#include <errno.h>
#include <time.h>
#include <stdbool.h>
#ifdef BR_CCACHE
static char ccache_path[PATH_MAX];
#endif
static char path[PATH_MAX];
static char sysroot[PATH_MAX];
/* As would be defined by gcc:
* https://gcc.gnu.org/onlinedocs/cpp/Standard-Predefined-Macros.html
* sizeof() on string literals includes the terminating \0. */
static char _time_[sizeof("-D__TIME__=\"HH:MM:SS\"")];
static char _date_[sizeof("-D__DATE__=\"MMM DD YYYY\"")];
/**
* GCC errors out with certain combinations of arguments (examples are
* -mfloat-abi={hard|soft} and -m{little|big}-endian), so we have to ensure
* that we only pass the predefined one to the real compiler if the inverse
* option isn't in the argument list.
* This specifies the worst case number of extra arguments we might pass
* Currently, we may have:
* -mfloat-abi=
* -march=
* -mcpu=
* -D__TIME__=
* -D__DATE__=
* -Wno-builtin-macro-redefined
*/
#define EXCLUSIVE_ARGS 6
static char *predef_args[] = {
#ifdef BR_CCACHE
ccache_path,
#endif
path,
"--sysroot", sysroot,
#ifdef BR_ABI
"-mabi=" BR_ABI,
#endif
#ifdef BR_NAN
"-mnan=" BR_NAN,
#endif
#ifdef BR_FPU
"-mfpu=" BR_FPU,
#endif
#ifdef BR_SOFTFLOAT
"-msoft-float",
#endif /* BR_SOFTFLOAT */
#ifdef BR_MODE
"-m" BR_MODE,
#endif
#ifdef BR_64
"-m64",
#endif
#ifdef BR_OMIT_LOCK_PREFIX
"-Wa,-momit-lock-prefix=yes",
#endif
#ifdef BR_NO_FUSED_MADD
"-mno-fused-madd",
#endif
#ifdef BR_BINFMT_FLAT
"-Wl,-elf2flt",
#endif
#ifdef BR_MIPS_TARGET_LITTLE_ENDIAN
"-EL",
#endif
#if defined(BR_MIPS_TARGET_BIG_ENDIAN) || defined(BR_ARC_TARGET_BIG_ENDIAN)
"-EB",
#endif
#ifdef BR_ADDITIONAL_CFLAGS
BR_ADDITIONAL_CFLAGS
#endif
};
/* A {string,length} tuple, to avoid computing strlen() on constants.
* - str must be a \0-terminated string
* - len does not account for the terminating '\0'
*/
struct str_len_s {
const char *str;
size_t len;
};
/* Define a {string,length} tuple. Takes an unquoted constant string as
* parameter. sizeof() on a string literal includes the terminating \0,
* but we don't want to count it.
*/
#define STR_LEN(s) { #s, sizeof(#s)-1 }
/* List of paths considered unsafe for cross-compilation.
*
* An unsafe path is one that points to a directory with libraries or
* headers for the build machine, which are not suitable for the target.
*/
static const struct str_len_s unsafe_paths[] = {
STR_LEN(/lib),
STR_LEN(/usr/include),
STR_LEN(/usr/lib),
STR_LEN(/usr/local/include),
STR_LEN(/usr/local/lib),
{ NULL, 0 },
};
/* Unsafe options are options that specify a potentialy unsafe path,
* that will be checked by check_unsafe_path(), below.
*/
static const struct str_len_s unsafe_opts[] = {
STR_LEN(-I),
STR_LEN(-idirafter),
STR_LEN(-iquote),
STR_LEN(-isystem),
STR_LEN(-L),
{ NULL, 0 },
};
/* Check if path is unsafe for cross-compilation. Unsafe paths are those
* pointing to the standard native include or library paths.
*
* We print the arguments leading to the failure. For some options, gcc
* accepts the path to be concatenated to the argument (e.g. -I/foo/bar)
* or separated (e.g. -I /foo/bar). In the first case, we need only print
* the argument as it already contains the path (arg_has_path), while in
* the second case we need to print both (!arg_has_path).
*
* If paranoid, exit in error instead of just printing a warning.
*/
static void check_unsafe_path(const char *arg,
const char *path,
int paranoid,
int arg_has_path)
{
const struct str_len_s *p;
for (p=unsafe_paths; p->str; p++) {
if (strncmp(path, p->str, p->len))
continue;
fprintf(stderr,
"%s: %s: unsafe header/library path used in cross-compilation: '%s%s%s'\n",
program_invocation_short_name,
paranoid ? "ERROR" : "WARNING",
arg,
arg_has_path ? "" : "' '", /* close single-quote, space, open single-quote */
arg_has_path ? "" : path); /* so that arg and path are properly quoted. */
if (paranoid)
exit(1);
}
}
/* Returns false if SOURCE_DATE_EPOCH was not defined in the environment.
*
* Returns true if SOURCE_DATE_EPOCH is in the environment and represent
* a valid timestamp, in which case the timestamp is formatted into the
* global variables _date_ and _time_.
*
* Aborts if SOURCE_DATE_EPOCH was set in the environment but did not
* contain a valid timestamp.
*
* Valid values are defined in the spec:
* https://reproducible-builds.org/specs/source-date-epoch/
* but we further restrict them to be positive or null.
*/
bool parse_source_date_epoch_from_env(void)
{
char *epoch_env, *endptr;
time_t epoch;
struct tm epoch_tm;
if ((epoch_env = getenv("SOURCE_DATE_EPOCH")) == NULL)
return false;
errno = 0;
epoch = (time_t) strtoll(epoch_env, &endptr, 10);
/* We just need to test if it is incorrect, but we do not
* care why it is incorrect.
*/
if ((errno != 0) || !*epoch_env || *endptr || (epoch < 0)) {
fprintf(stderr, "%s: invalid SOURCE_DATE_EPOCH='%s'\n",
program_invocation_short_name,
epoch_env);
exit(1);
}
tzset(); /* For localtime_r(), below. */
if (localtime_r(&epoch, &epoch_tm) == NULL) {
fprintf(stderr, "%s: cannot parse SOURCE_DATE_EPOCH=%s\n",
program_invocation_short_name,
getenv("SOURCE_DATE_EPOCH"));
exit(1);
}
if (!strftime(_time_, sizeof(_time_), "-D__TIME__=\"%T\"", &epoch_tm)) {
fprintf(stderr, "%s: cannot set time from SOURCE_DATE_EPOCH=%s\n",
program_invocation_short_name,
getenv("SOURCE_DATE_EPOCH"));
exit(1);
}
if (!strftime(_date_, sizeof(_date_), "-D__DATE__=\"%b %e %Y\"", &epoch_tm)) {
fprintf(stderr, "%s: cannot set date from SOURCE_DATE_EPOCH=%s\n",
program_invocation_short_name,
getenv("SOURCE_DATE_EPOCH"));
exit(1);
}
return true;
}
int main(int argc, char **argv)
{
char **args, **cur, **exec_args;
char *relbasedir, *absbasedir;
char *progpath = argv[0];
char *basename;
char *env_debug;
char *paranoid_wrapper;
int paranoid;
int ret, i, count = 0, debug;
/* Calculate the relative paths */
basename = strrchr(progpath, '/');
if (basename) {
*basename = '\0';
basename++;
relbasedir = malloc(strlen(progpath) + 7);
if (relbasedir == NULL) {
perror(__FILE__ ": malloc");
return 2;
}
sprintf(relbasedir, "%s/..", argv[0]);
absbasedir = realpath(relbasedir, NULL);
} else {
basename = progpath;
absbasedir = malloc(PATH_MAX + 1);
ret = readlink("/proc/self/exe", absbasedir, PATH_MAX);
if (ret < 0) {
perror(__FILE__ ": readlink");
return 2;
}
absbasedir[ret] = '\0';
for (i = ret; i > 0; i--) {
if (absbasedir[i] == '/') {
absbasedir[i] = '\0';
if (++count == 2)
break;
}
}
}
if (absbasedir == NULL) {
perror(__FILE__ ": realpath");
return 2;
}
/* Fill in the relative paths */
#ifdef BR_CROSS_PATH_REL
ret = snprintf(path, sizeof(path), "%s/" BR_CROSS_PATH_REL "/%s" BR_CROSS_PATH_SUFFIX, absbasedir, basename);
#elif defined(BR_CROSS_PATH_ABS)
ret = snprintf(path, sizeof(path), BR_CROSS_PATH_ABS "/%s" BR_CROSS_PATH_SUFFIX, basename);
#else
ret = snprintf(path, sizeof(path), "%s/bin/%s" BR_CROSS_PATH_SUFFIX, absbasedir, basename);
#endif
if (ret >= sizeof(path)) {
perror(__FILE__ ": overflow");
return 3;
}
#ifdef BR_CCACHE
ret = snprintf(ccache_path, sizeof(ccache_path), "%s/bin/ccache", absbasedir);
if (ret >= sizeof(ccache_path)) {
perror(__FILE__ ": overflow");
return 3;
}
#endif
ret = snprintf(sysroot, sizeof(sysroot), "%s/" BR_SYSROOT, absbasedir);
if (ret >= sizeof(sysroot)) {
perror(__FILE__ ": overflow");
return 3;
}
cur = args = malloc(sizeof(predef_args) +
(sizeof(char *) * (argc + EXCLUSIVE_ARGS)));
if (args == NULL) {
perror(__FILE__ ": malloc");
return 2;
}
/* start with predefined args */
memcpy(cur, predef_args, sizeof(predef_args));
cur += sizeof(predef_args) / sizeof(predef_args[0]);
#ifdef BR_FLOAT_ABI
/* add float abi if not overridden in args */
for (i = 1; i < argc; i++) {
if (!strncmp(argv[i], "-mfloat-abi=", strlen("-mfloat-abi=")) ||
!strcmp(argv[i], "-msoft-float") ||
!strcmp(argv[i], "-mhard-float"))
break;
}
if (i == argc)
*cur++ = "-mfloat-abi=" BR_FLOAT_ABI;
#endif
#ifdef BR_FP32_MODE
/* add fp32 mode if soft-float is not args or hard-float overrides soft-float */
int add_fp32_mode = 1;
for (i = 1; i < argc; i++) {
if (!strcmp(argv[i], "-msoft-float"))
add_fp32_mode = 0;
else if (!strcmp(argv[i], "-mhard-float"))
add_fp32_mode = 1;
}
if (add_fp32_mode == 1)
*cur++ = "-mfp" BR_FP32_MODE;
#endif
#if defined(BR_ARCH) || \
defined(BR_CPU)
/* Add our -march/cpu flags, but only if none of
* -march/mtune/mcpu are already specified on the commandline
*/
for (i = 1; i < argc; i++) {
if (!strncmp(argv[i], "-march=", strlen("-march=")) ||
!strncmp(argv[i], "-mtune=", strlen("-mtune=")) ||
!strncmp(argv[i], "-mcpu=", strlen("-mcpu=" )))
break;
}
if (i == argc) {
#ifdef BR_ARCH
*cur++ = "-march=" BR_ARCH;
#endif
#ifdef BR_CPU
*cur++ = "-mcpu=" BR_CPU;
#endif
}
#endif /* ARCH || CPU */
if (parse_source_date_epoch_from_env()) {
*cur++ = _time_;
*cur++ = _date_;
/* This has existed since gcc-4.4.0. */
*cur++ = "-Wno-builtin-macro-redefined";
}
paranoid_wrapper = getenv("BR_COMPILER_PARANOID_UNSAFE_PATH");
if (paranoid_wrapper && strlen(paranoid_wrapper) > 0)
paranoid = 1;
else
paranoid = 0;
/* Check for unsafe library and header paths */
for (i = 1; i < argc; i++) {
const struct str_len_s *opt;
for (opt=unsafe_opts; opt->str; opt++ ) {
/* Skip any non-unsafe option. */
if (strncmp(argv[i], opt->str, opt->len))
continue;
/* Handle both cases:
* - path is a separate argument,
* - path is concatenated with option.
*/
if (argv[i][opt->len] == '\0') {
i++;
if (i == argc)
break;
check_unsafe_path(argv[i-1], argv[i], paranoid, 0);
} else
check_unsafe_path(argv[i], argv[i] + opt->len, paranoid, 1);
}
}
/* append forward args */
memcpy(cur, &argv[1], sizeof(char *) * (argc - 1));
cur += argc - 1;
/* finish with NULL termination */
*cur = NULL;
exec_args = args;
#ifdef BR_CCACHE
if (getenv("BR_NO_CCACHE"))
/* Skip the ccache call */
exec_args++;
#endif
/* Debug the wrapper to see actual arguments passed to
* the compiler:
* unset, empty, or 0: do not trace
* set to 1 : trace all arguments on a single line
* set to 2 : trace one argument per line
*/
if ((env_debug = getenv("BR2_DEBUG_WRAPPER"))) {
debug = atoi(env_debug);
if (debug > 0) {
fprintf(stderr, "Toolchain wrapper executing:");
#ifdef BR_CCACHE_HASH
fprintf(stderr, "%sCCACHE_COMPILERCHECK='string:" BR_CCACHE_HASH "'",
(debug == 2) ? "\n " : " ");
#endif
#ifdef BR_CCACHE_BASEDIR
fprintf(stderr, "%sCCACHE_BASEDIR='" BR_CCACHE_BASEDIR "'",
(debug == 2) ? "\n " : " ");
#endif
for (i = 0; exec_args[i]; i++)
fprintf(stderr, "%s'%s'",
(debug == 2) ? "\n " : " ", exec_args[i]);
fprintf(stderr, "\n");
}
}
#ifdef BR_CCACHE_HASH
/* Allow compilercheck to be overridden through the environment */
if (setenv("CCACHE_COMPILERCHECK", "string:" BR_CCACHE_HASH, 0)) {
perror(__FILE__ ": Failed to set CCACHE_COMPILERCHECK");
return 3;
}
#endif
#ifdef BR_CCACHE_BASEDIR
/* Allow compilercheck to be overridden through the environment */
if (setenv("CCACHE_BASEDIR", BR_CCACHE_BASEDIR, 0)) {
perror(__FILE__ ": Failed to set CCACHE_BASEDIR");
return 3;
}
#endif
if (execv(exec_args[0], exec_args))
perror(path);
free(args);
return 2;
}