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basic: add STRERROR() wrapper for strerror_r()

This commit is contained in:
Zbigniew Jędrzejewski-Szmek 2022-10-07 12:28:31 +02:00
parent 0cbefc7d4f
commit 2c5d05b3cd
3 changed files with 56 additions and 0 deletions

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@ -6,6 +6,16 @@
#include "macro.h"
/* strerror(3) says that glibc uses a maximum length of 1024 bytes. */
#define ERRNO_BUF_LEN 1024
/* Note: the lifetime of the compound literal is the immediately surrounding block,
* see C11 §6.5.2.5, and
* https://stackoverflow.com/questions/34880638/compound-literal-lifetime-and-if-blocks
*
* Note that we use the GNU variant of strerror_r() here. */
#define STRERROR(errnum) strerror_r(abs(errnum), (char[ERRNO_BUF_LEN]){}, ERRNO_BUF_LEN)
static inline void _reset_errno_(int *saved_errno) {
if (*saved_errno < 0) /* Invalidated by UNPROTECT_ERRNO? */
return;

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@ -615,6 +615,8 @@ tests += [
[files('test-errno-list.c') +
generated_gperf_headers],
[files('test-errno-util.c')],
[files('test-ip-protocol-list.c') +
shared_generated_gperf_headers],

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@ -0,0 +1,44 @@
/* SPDX-License-Identifier: LGPL-2.1-or-later */
#include "errno-util.h"
#include "stdio-util.h"
#include "string-util.h"
#include "tests.h"
TEST(strerror_not_threadsafe) {
/* Just check that strerror really is not thread-safe. */
log_info("strerror(%d) → %s", 200, strerror(200));
log_info("strerror(%d) → %s", 201, strerror(201));
log_info("strerror(%d) → %s", INT_MAX, strerror(INT_MAX));
log_info("strerror(%d), strerror(%d) → %p, %p", 200, 201, strerror(200), strerror(201));
/* This call is not allowed, because the first returned string becomes invalid when
* we call strerror the second time:
*
* log_info("strerror(%d), strerror(%d) %s, %s", 200, 201, strerror(200), strerror(201));
*/
}
TEST(STRERROR) {
/* Just check that STRERROR really is thread-safe. */
log_info("STRERROR(%d) → %s", 200, STRERROR(200));
log_info("STRERROR(%d) → %s", 201, STRERROR(201));
log_info("STRERROR(%d), STRERROR(%d) → %s, %s", 200, 201, STRERROR(200), STRERROR(201));
const char *a = STRERROR(200), *b = STRERROR(201);
assert_se(strstr(a, "200"));
assert_se(strstr(b, "201"));
/* Check with negative values */
assert_se(streq(a, STRERROR(-200)));
assert_se(streq(b, STRERROR(-201)));
const char *c = STRERROR(INT_MAX);
char buf[DECIMAL_STR_MAX(int)];
xsprintf(buf, "%d", INT_MAX); /* INT_MAX is hexadecimal, use printf to convert to decimal */
log_info("STRERROR(%d) → %s", INT_MAX, c);
assert_se(strstr(c, buf));
}
DEFINE_TEST_MAIN(LOG_INFO);