[review v6] Use ctime_r and localtime_r for threadsafety

Christian Biesinger (Code Review)
2019-11-15T19:50:07Z

Use ctime_r and localtime_r for threadsafety

To make these calls threadsafe. localtime_r is provided by gnulib if
necessary, and for ctime_r we can just use it because it is in a linux-
specific file.

gdb/ChangeLog:

2019-11-15 Christian Biesinger <cbiesinger@google.com>

* maint.c (scoped_command_stats::print_time): Use localtime_r
instead of localtime (provided through gnulib if necessary).
* nat/linux-osdata.c (time_from_time_t): Use ctime_r instead
of ctime.

Change-Id: I329bbdc39d5b576f51859ba00f1617e024c30cbd
---
M gdb/ChangeLog
M gdb/maint.c
M gdb/nat/linux-osdata.c
3 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index f31552b..f727aa4 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,12 @@
2019-11-15 Christian Biesinger <cbiesinger@google.com>

+ * maint.c (scoped_command_stats::print_time): Use localtime_r
+ instead of localtime (provided through gnulib if necessary).
+ * nat/linux-osdata.c (time_from_time_t): Use ctime_r instead
+ of ctime.
+
+2019-11-15 Christian Biesinger <cbiesinger@google.com>
+
* gdbsupport/common-defs.h: Include time.h before pathmax.h to
avoid compile errors.

diff --git a/gdb/maint.c b/gdb/maint.c
index ec9f4ab..a253584 100644
--- a/gdb/maint.c
+++ b/gdb/maint.c
@@ -1039,10 +1039,11 @@
auto millis = ticks % 1000;

std::time_t as_time = system_clock::to_time_t (now);
- struct tm *tm = localtime (&as_time);
+ struct tm tm;
+ localtime_r (&as_time, &tm);

char out[100];
- strftime (out, sizeof (out), "%F %H:%M:%S", tm);
+ strftime (out, sizeof (out), "%F %H:%M:%S", &tm);

printf_unfiltered ("%s.%03d - %s\n", out, (int) millis, msg);
}
diff --git a/gdb/nat/linux-osdata.c b/gdb/nat/linux-osdata.c
index ca6acd3..d82c062 100644
--- a/gdb/nat/linux-osdata.c
+++ b/gdb/nat/linux-osdata.c
@@ -916,7 +916,11 @@
{
time_t t = (time_t) seconds;

- strncpy (time, ctime (&t), maxlen);
+ /* Per the ctime_r manpage, this buffer needs to be at least 26
+ characters long. */
+ char buf[30];
+ const char *time_str = ctime_r (&t, buf);
+ strncpy (time, time_str, maxlen);
time[maxlen - 1] = '\0';
}
}

--
Gerrit-Project: binutils-gdb
Gerrit-Branch: master
Gerrit-Change-Id: I329bbdc39d5b576f51859ba00f1617e024c30cbd
Gerrit-Change-Number: 475
Gerrit-PatchSet: 6
Gerrit-Owner: Christian Biesinger <cbiesinger@google.com>
Gerrit-Reviewer: Christian Biesinger <cbiesinger@google.com>
Gerrit-Reviewer: Kevin Buettner <kevinb@redhat.com>
Gerrit-MessageType: newpatchset