Signed-off-by: Mike Crute <m...@crute.us>
---
On Thu, Jan 12, 2023 at 03:32:52AM +0100, Ondrej Zajicek wrote:
That would work (with some minor modifications - abort() should be out
of condition, dbgf is FILE *, not fd, fileno() is not async-safe, so
we would need keep dbg_fd).
The disadantage is it would not write to log file, but only to debug
output (enabled with -d / -D option). If that is acceptable to you,
i would apply necessary changes.
I think it's okay that this only prints to the debug log file/stderr. I
think a person would try debug mode first when they encouter a crash
before doing more invasive debugging.
Here's a revised patch that incorporates your notes. Thanks!
sysdep/unix/io.c | 2 +-
sysdep/unix/log.c | 25 +++++++++++++++++++++++++
2 files changed, 26 insertions(+), 1 deletion(-)
diff --git a/sysdep/unix/io.c b/sysdep/unix/io.c
index 810e782d..06930fd7 100644
--- a/sysdep/unix/io.c
+++ b/sysdep/unix/io.c
@@ -2129,7 +2129,7 @@ watchdog_sigalrm(int sig UNUSED)
io_update_time();
/* We want core dump */
- abort();
+ watchdog_debug("Watchdog timer timed out.\n");
}
static inline void
diff --git a/sysdep/unix/log.c b/sysdep/unix/log.c
index 4e9df069..54614143 100644
--- a/sysdep/unix/log.c
+++ b/sysdep/unix/log.c
@@ -31,6 +31,7 @@
#include "lib/lists.h"
#include "sysdep/unix/unix.h"
+static int dbg_fd;
static FILE *dbgf;
static list *current_log_list;
static char *current_syslog_name; /* NULL -> syslog closed */
@@ -324,6 +325,24 @@ debug(const char *msg, ...)
va_end(args);
}
+/**
+ * watchdog_debug - async-safe write to debug output
+ * @msg: a string message
+ *
+ * This function prints the message @msg to the debugging output in a
+ * way that is async safe and can be used in signal handlers. No newline
+ * character is appended. It terminates the program after writing.
+ */
+void
+watchdog_debug(const char *msg)
+{
+ if (dbgf)
+ {
+ write(dbg_fd, msg, strlen(msg));
+ }
+ abort();
+}
+
static list *
default_log_list(int initial, const char **syslog_name)
{
@@ -427,7 +446,10 @@ log_init_debug(char *f)
if (!f)
dbgf = NULL;
else if (!*f)
+ {
dbgf = stderr;
+ dbg_fd = STDERR_FILENO;
+ }
else if (!(dbgf = fopen(f, "a")))
{
/* Cannot use die() nor log() here, logging is not yet initialized */
@@ -435,5 +457,8 @@ log_init_debug(char *f)
exit(1);
}
if (dbgf)
+ {
setvbuf(dbgf, NULL, _IONBF, 0);
+ dbg_fd = fileno(dbgf);
+ }
}
--
2.39.0
