[PATCH v3] strerror.3: Change strerror() reference from MT-Unsafe to MT-Safe

[Alejandro Colomar <alx@kernel.org>]

From: Shani Leviim <sleviim@redhat.com>

The information in this patch was obtained from a glibc upstream patch,
commit ID 28aff047818eb1726394296d27b9c7885340bead

According the patch above, for glibc versions >=2.32,
strerror() is considered MT-Safe, and the man page should be changed accordingly.

Signed-off-by: Shani Leviim <sleviim@redhat.com>
Cc: Florian Weimer <fweimer@redhat.com>
Cc: Carlos O'Donell <carlos@redhat.com>
Cc: Sergei Gromeniuk <sgromeni@redhat.com>
Cc: Gobinda Das <godas@redhat.com>
Signed-off-by: Alejandro Colomar <alx@kernel.org>
---

v3: Added the CCs from the original thread.

 man3/strerror.3 | 31 +++++++++++++++----------------
 1 file changed, 15 insertions(+), 16 deletions(-)

diff --git a/man3/strerror.3 b/man3/strerror.3
index 8b36d6487..73199ef85 100644
--- a/man3/strerror.3
+++ b/man3/strerror.3
@@ -72,11 +72,12 @@ .SH DESCRIPTION
 is
 .BR EINVAL ,
 the returned description will be "Invalid argument".)
-This string must not be modified by the application, but may be
-modified by a subsequent call to
+This string must not be modified by the application,
+and the returned pointer will be invalidated on a subsequent call to
 .BR strerror ()
 or
-.BR strerror_l ().
+.BR strerror_l (),
+or if the thread that obtained the string exits.
 No other library function, including
 .BR perror (3),
 will modify this string.
@@ -101,12 +102,12 @@ .SH DESCRIPTION
 as an argument, this function returns a pointer to the string "EPERM".
 .\"
 .SS strerror_r()
-The
 .BR strerror_r ()
-function is similar to
+is like
 .BR strerror (),
-but is
-thread safe.
+but might use the supplied buffer
+.I buf
+instead of allocating one internally.
 This function is available in two versions:
 an XSI-compliant version specified in POSIX.1-2001
 (available since glibc 2.3.4, but not POSIX-compliant until glibc 2.13),
@@ -231,7 +232,7 @@ .SH ATTRIBUTES
 T}	Thread safety	T{
 .na
 .nh
-MT-Unsafe race:strerror
+MT-Safe
 T}
 T{
 .na
@@ -246,6 +247,10 @@ .SH ATTRIBUTES
 .BR strerror_l ()
 T}	Thread safety	MT-Safe
 .TE
+.PP
+Before glibc 2.32,
+.BR strerror ()
+is not MT-Safe.
 .SH STANDARDS
 .TP
 .BR strerror ()
@@ -301,13 +306,6 @@ .SH HISTORY
 .BR strerrordesc_np ()
 glibc 2.32.
 .SH NOTES
-The GNU C Library uses a buffer of 1024 characters for
-.BR strerror ().
-This buffer size therefore should be sufficient to avoid an
-.B ERANGE
-error when calling
-.BR strerror_r ().
-.PP
 .BR strerrorname_np ()
 and
 .BR strerrordesc_np ()
@@ -318,4 +316,5 @@ .SH SEE ALSO
 .BR error (3),
 .BR perror (3),
 .BR strsignal (3),
-.BR locale (7)
+.BR locale (7),
+.BR signal-safety (7)
-- 
2.40.1