debug-trigger: Do what we can to debug unresponsive systems
debug-trigger is a small daemon which translates an external signal that
the system is unresponsive into a system crash for debug data
collection.
Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
Change-Id: Ic04f1a95aaf651d56b75f5261d8a6f76d34477a7
diff --git a/main.c b/main.c
new file mode 100644
index 0000000..d55b706
--- /dev/null
+++ b/main.c
@@ -0,0 +1,114 @@
+// SPDX-License-Identifier: Apache-2.0
+// Copyright (C) 2021 IBM Corp.
+
+#include <err.h>
+#include <fcntl.h>
+#include <getopt.h>
+#include <libgen.h>
+#include <limits.h>
+#include <linux/reboot.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/reboot.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+static int process(int source, int sink)
+{
+ ssize_t ingress;
+ char command;
+
+ while ((ingress = read(source, &command, sizeof(command))) == sizeof(command)) {
+ static const char action = 'c';
+ ssize_t rc;
+
+ switch (command) {
+ case 'D': /* Debug */
+ sync();
+
+ if ((rc = write(sink, &action, sizeof(action))) == sizeof(action))
+ continue;
+
+ if (rc == -1) {
+ warn("Failed to execute command 0x%02x (%c)",
+ command, command);
+ } else {
+ warnx("Failed to execute command 0x%02x (%c): %zd",
+ command, command, rc);
+ }
+ break;
+ case 'R':
+ sync();
+
+ if ((rc = reboot(LINUX_REBOOT_CMD_RESTART))) {
+ if (rc == -1)
+ warn("Failed to reboot BMC");
+ else
+ warnx("Failed to reboot BMC: %zd", rc);
+ }
+ break;
+ default:
+ warnx("Unexpected command: 0x%02x (%c)", command, command);
+ }
+ }
+
+ if (ingress == -1)
+ warn("Failed to read from source");
+
+ return ingress;
+}
+
+int main(int argc, char * const argv[])
+{
+ char devnode[PATH_MAX];
+ char *devid;
+ int source;
+ int sink;
+
+ while (1) {
+ static struct option long_options[] = {
+ {0, 0, 0, 0},
+ };
+ int c;
+
+ c = getopt_long(argc, argv, "", long_options, NULL);
+ if (c == -1)
+ break;
+ }
+
+ source = 0;
+ sink = 1;
+
+ if (optind < argc) {
+ char devpath[PATH_MAX];
+
+ strncpy(devpath, argv[optind], sizeof(devpath));
+ devpath[PATH_MAX - 1] = '\0';
+ devid = basename(devpath);
+
+ strncpy(devnode, "/dev/", sizeof(devnode));
+ strncat(devnode, devid, sizeof(devnode));
+ devnode[PATH_MAX - 1] = '\0';
+
+ if ((source = open(devnode, O_RDONLY)) == -1)
+ err(EXIT_FAILURE, "Failed to open %s", devnode);
+
+ optind++;
+ }
+
+ if (optind < argc) {
+ if ((sink = open(argv[optind], O_WRONLY)) == -1)
+ err(EXIT_FAILURE, "Failed to open %s", argv[optind]);
+
+ optind++;
+ }
+
+ if (optind < argc)
+ err(EXIT_FAILURE, "Found %d unexpected arguments", argc - optind);
+
+ if (process(source, sink) < 0)
+ errx(EXIT_FAILURE, "Failure while processing command stream");
+
+ return 0;
+}