[tip: core/rcu] tools/nolibc: Make getpgrp() fall back to getpgid(0)

["tip-bot2 for Willy Tarreau" <tip-bot2@linutronix.de>]

The following commit has been merged into the core/rcu branch of tip:

Commit-ID:     c0c7c103756fee25aadfd5c36f7b86e318f9abb4
Gitweb:        https://git.kernel.org/tip/c0c7c103756fee25aadfd5c36f7b86e318f9abb4
Author:        Willy Tarreau <w@1wt.eu>
AuthorDate:    Thu, 21 Jan 2021 08:20:25 +01:00
Committer:     Paul E. McKenney <paulmck@kernel.org>
CommitterDate: Thu, 21 Jan 2021 10:06:44 -08:00

tools/nolibc: Make getpgrp() fall back to getpgid(0)

The getpgrp() syscall is not implemented on arm64, so this commit instead
uses getpgid(0) when getpgrp() is not available.  This is a port of
nolibc's upstream commit 2379f25073f9 to the Linux kernel.

Fixes: 66b6f755ad45 ("rcutorture: Import a copy of nolibc")
Tested-by: Valentin Schneider <valentin.schneider@arm.com>
Tested-by: Mark Rutland <mark.rutland@arm.com> [arm64]
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
---
 tools/include/nolibc/nolibc.h | 20 +++++++++++++++++++-
 1 file changed, 19 insertions(+), 1 deletion(-)

diff --git a/tools/include/nolibc/nolibc.h b/tools/include/nolibc/nolibc.h
index 5fda4d8..9209da8 100644
--- a/tools/include/nolibc/nolibc.h
+++ b/tools/include/nolibc/nolibc.h
@@ -1545,9 +1545,15 @@ int sys_getdents64(int fd, struct linux_dirent64 *dirp, int count)
 }
 
 static __attribute__((unused))
+pid_t sys_getpgid(pid_t pid)
+{
+	return my_syscall1(__NR_getpgid, pid);
+}
+
+static __attribute__((unused))
 pid_t sys_getpgrp(void)
 {
-	return my_syscall0(__NR_getpgrp);
+	return sys_getpgid(0);
 }
 
 static __attribute__((unused))
@@ -1951,6 +1957,18 @@ int getdents64(int fd, struct linux_dirent64 *dirp, int count)
 }
 
 static __attribute__((unused))
+pid_t getpgid(pid_t pid)
+{
+	pid_t ret = sys_getpgid(pid);
+
+	if (ret < 0) {
+		SET_ERRNO(-ret);
+		ret = -1;
+	}
+	return ret;
+}
+
+static __attribute__((unused))
 pid_t getpgrp(void)
 {
 	pid_t ret = sys_getpgrp();