Revert "os: log: make LogVMessageVerb() signal safe"

This reverts commit 5962211612decdbe173a1389cc00c26d1a8a8724.

Part-of: <https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/2036>

2 files changed, 29 insertions, 9 deletions

diff --git a/include/os.h b/include/os.h
index 2f43e4eda..3949ff5aa 100644
--- a/include/os.h
+++ b/include/os.h
@@ -327,6 +327,9 @@ _X_ATTRIBUTE_PRINTF(2, 3);
 extern _X_EXPORT void
 LogMessageVerbSigSafe(MessageType type, int verb, const char *format, ...)
 _X_ATTRIBUTE_PRINTF(3, 4);
+extern _X_EXPORT void
+LogVMessageVerbSigSafe(MessageType type, int verb, const char *format, va_list args)
+_X_ATTRIBUTE_PRINTF(3, 0);
 
 extern _X_EXPORT void
 LogVHdrMessageVerb(MessageType type, int verb,
@@ -376,9 +379,6 @@ xorg_backtrace(void);
 typedef _sigset_t sigset_t;
 #endif
 
-/* should not be used anymore, just for backwards compat with drivers */
-#define LogVMessageVerbSigSafe(...) LogVMessageVerb(__VA_ARGS__)
-
 /* only for backwards compat with drivers that haven't kept up yet
    (xf86-video-intel)
 
diff --git a/os/log.c b/os/log.c
index c901234fe..bcd07a0b9 100644
--- a/os/log.c
+++ b/os/log.c
@@ -680,17 +680,21 @@ static inline void writeLog(int verb, char *buf, int len)
     LogSWrite(verb, buf, len, (buf[len - 1] == '\n'));
 }
 
-/* signal safe */
 void
 LogVMessageVerb(MessageType type, int verb, const char *format, va_list args)
 {
     char buf[LOG_MSG_BUF_SIZE];
 
+    if (inSignalContext) {
+        LogVMessageVerbSigSafe(type, verb, format, args);
+        return;
+    }
+
     size_t len = prepMsgHdr(type, verb, buf);
     if (len == -1)
         return;
 
-    len += vpnprintf(&buf[len], sizeof(buf) - len, format, args);
+    len += Xvscnprintf(&buf[len], sizeof(buf) - len, format, args);
 
     writeLog(verb, buf, len);
 }
@@ -723,25 +727,41 @@ LogMessageVerbSigSafe(MessageType type, int verb, const char *format, ...)
 {
     va_list ap;
     va_start(ap, format);
-    LogVMessageVerb(type, verb, format, ap);
+    LogVMessageVerbSigSafe(type, verb, format, ap);
     va_end(ap);
 }
 
 void
+LogVMessageVerbSigSafe(MessageType type, int verb, const char *format, va_list args)
+{
+    char buf[LOG_MSG_BUF_SIZE];
+
+    int len = prepMsgHdr(type, verb, buf);
+    if (len == -1)
+        return;
+
+    len += vpnprintf(&buf[len], sizeof(buf) - len, format, args);
+
+    writeLog(verb, buf, len);
+}
+
+void
 LogVHdrMessageVerb(MessageType type, int verb, const char *msg_format,
                    va_list msg_args, const char *hdr_format, va_list hdr_args)
 {
     char buf[LOG_MSG_BUF_SIZE];
+    int (*vprintf_func)(char *, int, const char* _X_RESTRICT_KYWD f, va_list args)
+            _X_ATTRIBUTE_PRINTF(3, 0) = (inSignalContext ? vpnprintf : Xvscnprintf);
 
     size_t len = prepMsgHdr(type, verb, buf);
     if (len == -1)
         return;
 
     if (hdr_format && sizeof(buf) - len > 1)
-        len += vpnprintf(&buf[len], sizeof(buf) - len, hdr_format, hdr_args);
+        len += vprintf_func(&buf[len], sizeof(buf) - len, hdr_format, hdr_args);
 
     if (msg_format && sizeof(buf) - len > 1)
-        len += vpnprintf(&buf[len], sizeof(buf) - len, msg_format, msg_args);
+        len += vprintf_func(&buf[len], sizeof(buf) - len, msg_format, msg_args);
 
     writeLog(verb, buf, len);
 }
@@ -921,7 +941,7 @@ ErrorF(const char *f, ...)
 void
 VErrorFSigSafe(const char *f, va_list args)
 {
-    LogVMessageVerb(X_ERROR, -1, f, args);
+    LogVMessageVerbSigSafe(X_ERROR, -1, f, args);
 }
 
 void