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[glibc/azanella/wait-refactor] linux: Use waitid on wait4 if __NR_wait4 is not defined
- From: Adhemerval Zanella <azanella at sourceware dot org>
- To: glibc-cvs at sourceware dot org
- Date: 13 Nov 2019 20:59:07 -0000
- Subject: [glibc/azanella/wait-refactor] linux: Use waitid on wait4 if __NR_wait4 is not defined
https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=64f9e324868d270883f1e5a0810b775b1cdd1229
commit 64f9e324868d270883f1e5a0810b775b1cdd1229
Author: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Date: Wed Nov 13 17:45:13 2019 -0300
linux: Use waitid on wait4 if __NR_wait4 is not defined
If the wait4 syscall is not avaliable (such as y2038 safe 32-bit
systems) it uses waitid syscall instead. For full support we need
the 5.4+ kernel as that allows a pid of 0 with the P_PGID idtype.
Co-authored-by: Alistair Francis <alistair.francis@wdc.com>
Diff:
---
sysdeps/unix/sysv/linux/syscalls.list | 1 -
sysdeps/unix/sysv/linux/wait4.c | 84 +++++++++++++++++++++++++++++++++++
2 files changed, 84 insertions(+), 1 deletion(-)
diff --git a/sysdeps/unix/sysv/linux/syscalls.list b/sysdeps/unix/sysv/linux/syscalls.list
index 603e517..5f1352a 100644
--- a/sysdeps/unix/sysv/linux/syscalls.list
+++ b/sysdeps/unix/sysv/linux/syscalls.list
@@ -67,7 +67,6 @@ swapoff - swapoff i:s __swapoff swapoff
unshare EXTRA unshare i:i unshare
uselib EXTRA uselib i:s __compat_uselib uselib@GLIBC_2.0:GLIBC_2.23
utime - utime i:sP utime
-wait4 - wait4 i:iWiP __wait4 wait4
chown - chown i:sii __libc_chown __chown chown
diff --git a/sysdeps/unix/sysv/linux/wait4.c b/sysdeps/unix/sysv/linux/wait4.c
new file mode 100644
index 0000000..c722753
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/wait4.c
@@ -0,0 +1,84 @@
+/* Linux wait4 syscall implementation.
+ Copyright (C) 2019 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 <sys/wait.h>
+#include <sys/resource.h>
+#include <sysdep-cancel.h>
+
+__pid_t
+__wait4 (__pid_t pid, int *stat_loc, int options, struct rusage *usage)
+{
+#if __NR_wait4
+ return SYSCALL_CANCEL (wait4, pid, stat_loc, options, usage);
+#else
+ idtype_t idtype = P_PID;
+
+ if (pid < -1)
+ {
+ idtype = P_PGID;
+ pid *= -1;
+ }
+ else if (pid == -1)
+ {
+ idtype = P_ALL;
+ }
+ else if (pid == 0)
+ {
+ /* Linux Kernels 5.4 support pid 0 with P_PGID to specify wait on
+ * the current PID's group. Earlier kernels will return -EINVAL.
+ */
+ idtype = P_PGID;
+ }
+
+ options |= WEXITED;
+
+ siginfo_t infop;
+ if (SYSCALL_CANCEL (waitid, idtype, pid, &infop, options, usage) < 0)
+ return -1;
+
+ if (stat_loc)
+ {
+ *stat_loc = 0;
+ switch (infop.si_code)
+ {
+ case CLD_EXITED:
+ *stat_loc = W_EXITCODE (infop.si_status, 0);
+ break;
+ case CLD_DUMPED:
+ *stat_loc = WCOREDUMP (infop.si_signo);
+ /* Fallthrough */
+ case CLD_KILLED:
+ *stat_loc |= infop.si_status;
+ break;
+ case CLD_TRAPPED:
+ case CLD_STOPPED:
+ *stat_loc = W_STOPCODE (infop.si_status);
+ break;
+ case CLD_CONTINUED:
+ *stat_loc = 0xffff;
+ break;
+ default:
+ *stat_loc = 0;
+ break;
+ }
+ }
+
+ return infop.si_pid;
+#endif
+}
+weak_alias (__wait4, wait4)