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authorAdhemerval Zanella <adhemerval.zanella@linaro.org>2021-06-16 13:44:03 -0300
committerAdhemerval Zanella <adhemerval.zanella@linaro.org>2021-06-22 12:09:52 -0300
commit92f7b465101c23e45f66c6ad25ba243df49556a0 (patch)
tree8af981c64cf0a77245f7bf1db86af48a44f5ca75 /support
parent52a5fe70a2c77935afe807fb6e904e512ddd894e (diff)
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support: Add support_create_timer
It is a simple wrapper over timer_create, timer_settime, and sigaction. It will be used to check for large timeout to trigger an EINTR and to avoid use a large timeout (as for alarm()). Reviewed-by: Lukasz Majewski <lukma@denx.de>
Diffstat (limited to 'support')
-rw-r--r--support/Makefile1
-rw-r--r--support/support.h11
-rw-r--r--support/support_create_timer.c69
3 files changed, 81 insertions, 0 deletions
diff --git a/support/Makefile b/support/Makefile
index f3ebaa8d2e..278f4627d8 100644
--- a/support/Makefile
+++ b/support/Makefile
@@ -50,6 +50,7 @@ libsupport-routines = \
support_chroot \
support_copy_file \
support_copy_file_range \
+ support_create_timer \
support_descriptor_supports_holes \
support_descriptors \
support_enter_mount_namespace \
diff --git a/support/support.h b/support/support.h
index 874204b7fc..9ec8ecb8d7 100644
--- a/support/support.h
+++ b/support/support.h
@@ -24,6 +24,7 @@
#define SUPPORT_H
#include <stdbool.h>
+#include <stdint.h>
#include <stddef.h>
#include <sys/cdefs.h>
/* For mode_t. */
@@ -153,6 +154,16 @@ extern bool support_select_modifies_timeout (void);
tv_usec larger than 1000000. */
extern bool support_select_normalizes_timeout (void);
+/* Create a timer that trigger after SEC seconds and NSEC nanoseconds. If
+ REPEAT is true the timer will repeat indefinitely. If CALLBACK is not
+ NULL, the function will be called when the timer expires; otherwise a
+ dummy empty function is used instead.
+ This is implemented with POSIX per-process timer with SIGEV_SIGNAL. */
+timer_t support_create_timer (uint64_t sec, long int nsec, bool repeat,
+ void (*callback)(int));
+/* Disable the timer TIMER. */
+void support_delete_timer (timer_t timer);
+
__END_DECLS
#endif /* SUPPORT_H */
diff --git a/support/support_create_timer.c b/support/support_create_timer.c
new file mode 100644
index 0000000000..c93aaa5c6b
--- /dev/null
+++ b/support/support_create_timer.c
@@ -0,0 +1,69 @@
+/* Create a periodic timer.
+ Copyright (C) 2021 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <https://www.gnu.org/licenses/>. */
+
+#include <support/check.h>
+#include <support/support.h>
+#include <support/xsignal.h>
+#include <time.h>
+
+static void
+dummy_alrm_handler (int sig)
+{
+}
+
+timer_t
+support_create_timer (uint64_t sec, long int nsec, bool repeat,
+ void (*callback)(int))
+{
+ struct sigaction sa;
+ sa.sa_handler = callback != NULL ? callback : dummy_alrm_handler;
+ sigemptyset (&sa.sa_mask);
+ sa.sa_flags = 0;
+ xsigaction (SIGALRM, &sa, NULL);
+
+ struct sigevent ev = {
+ .sigev_notify = SIGEV_SIGNAL,
+ .sigev_signo = SIGALRM
+ };
+ timer_t timerid;
+ int r = timer_create (CLOCK_REALTIME, &ev, &timerid);
+ if (r == -1)
+ FAIL_EXIT1 ("timer_create: %m");
+
+ /* Single timer with 0.1s. */
+ struct itimerspec its =
+ {
+ { .tv_sec = repeat ? sec : 0, .tv_nsec = repeat ? nsec : 0 },
+ { .tv_sec = sec, .tv_nsec = nsec }
+ };
+ r = timer_settime (timerid, 0, &its, NULL);
+ if (r == -1)
+ FAIL_EXIT1 ("timer_settime: %m");
+
+ return timerid;
+}
+
+/* Disable the timer TIMER. */
+void
+support_delete_timer (timer_t timer)
+{
+ int r = timer_delete (timer);
+ if (r == -1)
+ FAIL_EXIT1 ("timer_delete: %m");
+ xsignal (SIGALRM, SIG_DFL);
+}