Bug fix for ppc64 and s390/x

that is avoid arg0 of a program be missed in the console library. Signed-off-by: Werner Fink <[email protected]>
bitstreamout · Dec 3, 2021 · f2f8b05 · f2f8b05
1 parent fcb9e0c
commit f2f8b05
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Showing 4 changed files with 25 additions and 5 deletions.
diff --git a/blogctl.8 b/blogctl.8
@@ -53,6 +53,14 @@ This let the daemon disconnect from system console.
 .TP
 .B reactivate
 Whereas this cause the daemon reconnect to system console.
+.TP
+.B final
+Evoke the daemon to rename an already open log file
+.I /var/log/boot.log
+to the new name
+.I /var/log/boot.old
+as well as mask it own program name in the process table
+with the @ character.
 .SH SEE ALSO
 .BR blogd (8),
 .BR systemd (1),

diff --git a/blogd.c b/blogd.c
@@ -221,7 +221,6 @@ static volatile pid_t pid = -1;
 
 static void flush_handler (void) attribute((noinline));
 static void exit_handler (void) attribute((noinline));
-volatile char *arg0;
 
 /*
  * Now do the job
@@ -230,6 +229,7 @@ int main(int argc, char *argv[])
 {
     char ptsname[NAME_MAX+1];
     const char *tty, *stt;
+    volatile char *arg0;
     struct console *c;
     struct termios o;
     struct winsize w;
@@ -248,6 +248,7 @@ int main(int argc, char *argv[])
 	warn("could not tell system to show its status");
 
     arg0 = (volatile char*)argv[0];
+    remember_arg0(arg0);
 
     while ((arg = getopt(argc, argv, "f")) != -1) {
 	switch (arg) {

diff --git a/libconsole/console.c b/libconsole/console.c
@@ -50,7 +50,17 @@
 #endif
 
 int final = 0;
-extern volatile char *arg0;
+static volatile char *_arg0;
+
+/*
+ * Avoid trouble if linked with e.g. blogger as there
+ * is no external arg0 but linker on ppc64 and s390/x
+ * seems to expect this.
+ */
+void remember_arg0(volatile char *arg0)
+{
+    _arg0 = arg0;
+}
 
 /*
  * Used to ignore some signals during epoll_pwait(2) or ppoll(2)
@@ -1044,13 +1054,13 @@ static void socket_handler(int fd)
 	enqry = ANSWER_ACK;
 	safeout(fd, enqry, strlen(enqry)+1, SSIZE_MAX);
 
-	if (!final) {
+	if (!final && _arg0) {
 	    int ret;
 
 	    final = 1;
 
-	    if (arg0[0] != '@')
-		arg0[0] = '@';
+	    if (_arg0[0] != '@')
+		_arg0[0] = '@';
 
 	    ret = rename(BOOT_LOGFILE, BOOT_OLDLOGFILE);
 	    if (ret < 0) {

diff --git a/libconsole/libconsole.h b/libconsole/libconsole.h
@@ -122,6 +122,7 @@ extern int evmax;
 extern volatile sig_atomic_t signaled;
 extern volatile sig_atomic_t nsigsys;
 
+extern void remember_arg0(volatile char *arg0);
 extern ssize_t safein (int fd, void *ptr, size_t s);
 extern void safeout (int fd, const void *ptr, size_t s, ssize_t max);