From 230586043d9efd3a431b64427b0760b3ffbd6b58 Mon Sep 17 00:00:00 2001
From: Klaus Wenninger <klaus.wenninger@aon.at>
Date: Wed, 13 Jul 2022 14:46:38 +0200
Subject: [PATCH] Fix: Be a bit more descriptive on issues opening
watchdog-devices
Both when running as daemon and with 'test/query-watchdog'
---
src/sbd-common.c | 495 +++++++++++++++++++++++++++++++++----------------------
1 file changed, 302 insertions(+), 193 deletions(-)
diff --git a/src/sbd-common.c b/src/sbd-common.c
index b14575f..f3f226a 100644
--- a/src/sbd-common.c
+++ b/src/sbd-common.c
@@ -118,6 +118,62 @@ usage(void)
, cmdname);
}
+#define MAX_WATCHDOGS 64
+#define SYS_CLASS_WATCHDOG "/sys/class/watchdog"
+#define SYS_CHAR_DEV_DIR "/sys/dev/char"
+#define WATCHDOG_NODEDIR "/dev/"
+
+static bool
+is_watchdog(dev_t device)
+{
+ static int num_watchdog_devs = 0;
+ static dev_t watchdog_devs[MAX_WATCHDOGS];
+ struct dirent *entry;
+ int i;
+
+ /* populate on first call */
+ if (num_watchdog_devs == 0) {
+ DIR *dp;
+
+ watchdog_devs[0] = makedev(10,130);
+ num_watchdog_devs = 1;
+
+ /* get additional devices from /sys/class/watchdog */
+ dp = opendir(SYS_CLASS_WATCHDOG);
+ if (dp) {
+ while ((entry = readdir(dp))) {
+ if (entry->d_type == DT_LNK) {
+ FILE *file;
+ char entry_name[NAME_MAX+sizeof(SYS_CLASS_WATCHDOG)+5];
+
+ snprintf(entry_name, sizeof(entry_name),
+ SYS_CLASS_WATCHDOG "/%s/dev", entry->d_name);
+ file = fopen(entry_name, "r");
+ if (file) {
+ int major, minor;
+
+ if (fscanf(file, "%d:%d", &major, &minor) == 2) {
+ watchdog_devs[num_watchdog_devs++] = makedev(major, minor);
+ }
+ fclose(file);
+ if (num_watchdog_devs == MAX_WATCHDOGS) {
+ break;
+ }
+ }
+ }
+ }
+ closedir(dp);
+ }
+ }
+
+ for (i=0; i < num_watchdog_devs; i++) {
+ if (device == watchdog_devs[i]) {
+ return true;
+ }
+ }
+ return false;
+}
+
static int
watchdog_init_interval_fd(int wdfd, int timeout)
{
@@ -173,20 +229,27 @@ watchdog_tickle(void)
static int
watchdog_init_fd(char *wddev, int timeout)
{
- int wdfd;
+ int wdfd;
+
+ wdfd = open(wddev, O_WRONLY);
+ if (wdfd >= 0) {
+ if (((timeout >= 0) && (watchdog_init_interval_fd(wdfd, timeout) < 0)) ||
+ (watchdog_tickle_fd(wdfd, wddev) < 0)) {
+ close(wdfd);
+ return -1;
+ }
+ } else {
+ struct stat statbuf;
- wdfd = open(wddev, O_WRONLY);
- if (wdfd >= 0) {
- if (((timeout >= 0) && (watchdog_init_interval_fd(wdfd, timeout) < 0))
- || (watchdog_tickle_fd(wdfd, wddev) < 0)) {
- close(wdfd);
- return -1;
- }
- } else {
- cl_perror("Cannot open watchdog device '%s'", wddev);
- return -1;
- }
- return wdfd;
+ if(!stat(wddev, &statbuf) && S_ISCHR(statbuf.st_mode) &&
+ is_watchdog(statbuf.st_rdev)) {
+ cl_perror("Cannot open watchdog device '%s'", wddev);
+ } else {
+ cl_perror("Seems as if '%s' isn't a valid watchdog-device", wddev);
+ }
+ return -1;
+ }
+ return wdfd;
}
int
@@ -250,17 +313,13 @@ watchdog_close(bool disarm)
watchdogfd = -1;
}
-#define MAX_WATCHDOGS 64
-#define SYS_CLASS_WATCHDOG "/sys/class/watchdog"
-#define SYS_CHAR_DEV_DIR "/sys/dev/char"
-#define WATCHDOG_NODEDIR "/dev/"
-#define WATCHDOG_NODEDIR_LEN 5
-
struct watchdog_list_item {
dev_t dev;
char *dev_node;
char *dev_ident;
char *dev_driver;
+ pid_t busy_pid;
+ char *busy_name;
struct watchdog_list_item *next;
};
@@ -276,184 +335,223 @@ static int watchdog_list_items = 0;
static void
watchdog_populate_list(void)
{
- dev_t watchdogs[MAX_WATCHDOGS + 1] =
- {makedev(10,130), 0};
- int num_watchdogs = 1;
- struct dirent *entry;
- char entry_name[280];
- DIR *dp;
- char buf[280] = "";
- struct link_list_item *link_list = NULL;
-
- if (watchdog_list != NULL) {
- return;
- }
+ struct dirent *entry;
+ char entry_name[sizeof(WATCHDOG_NODEDIR)+NAME_MAX];
+ DIR *dp;
+ char buf[NAME_MAX+sizeof(WATCHDOG_NODEDIR)] = "";
+ struct link_list_item *link_list = NULL;
- /* get additional devices from /sys/class/watchdog */
- dp = opendir(SYS_CLASS_WATCHDOG);
- if (dp) {
- while ((entry = readdir(dp))) {
- if (entry->d_type == DT_LNK) {
- FILE *file;
-
- snprintf(entry_name, sizeof(entry_name),
- SYS_CLASS_WATCHDOG "/%s/dev", entry->d_name);
- file = fopen(entry_name, "r");
- if (file) {
- int major, minor;
-
- if (fscanf(file, "%d:%d", &major, &minor) == 2) {
- watchdogs[num_watchdogs++] = makedev(major, minor);
- }
- fclose(file);
- if (num_watchdogs == MAX_WATCHDOGS) {
- break;
- }
- }
- }
- }
- closedir(dp);
- }
+ if (watchdog_list != NULL) {
+ return;
+ }
- /* search for watchdog nodes in /dev */
- dp = opendir(WATCHDOG_NODEDIR);
- if (dp) {
- /* first go for links and memorize them */
- while ((entry = readdir(dp))) {
- if (entry->d_type == DT_LNK) {
- int len;
-
- snprintf(entry_name, sizeof(entry_name),
- WATCHDOG_NODEDIR "%s", entry->d_name);
-
- /* !realpath(entry_name, buf) unfortunately does a stat on
- * target so we can't really use it to check if links stay
- * within /dev without triggering e.g. AVC-logs (with
- * SELinux policy that just allows stat within /dev).
- * Without canonicalization that doesn't actually touch the
- * filesystem easily available introduce some limitations
- * for simplicity:
- * - just simple path without '..'
- * - just one level of symlinks (avoid e.g. loop-checking)
- */
- len = readlink(entry_name, buf, sizeof(buf) - 1);
- if ((len < 1) ||
- (len > sizeof(buf) - WATCHDOG_NODEDIR_LEN - 1)) {
- continue;
- }
- buf[len] = '\0';
- if (buf[0] != '/') {
- memmove(&buf[WATCHDOG_NODEDIR_LEN], buf, len+1);
- memcpy(buf, WATCHDOG_NODEDIR, WATCHDOG_NODEDIR_LEN);
- len += WATCHDOG_NODEDIR_LEN;
- }
- if (strstr(buf, "/../") ||
- strncmp(WATCHDOG_NODEDIR, buf, WATCHDOG_NODEDIR_LEN)) {
- continue;
- } else {
- /* just memorize to avoid statting the target - SELinux */
- struct link_list_item *lli =
- calloc(1, sizeof(struct link_list_item));
-
- lli->dev_node = strdup(buf);
- lli->link_name = strdup(entry_name);
- lli->next = link_list;
- link_list = lli;
- }
- }
- }
+ /* search for watchdog nodes in /dev */
+ dp = opendir(WATCHDOG_NODEDIR);
+ if (dp) {
+ /* first go for links and memorize them */
+ while ((entry = readdir(dp))) {
+ if (entry->d_type == DT_LNK) {
+ int len;
+
+ snprintf(entry_name, sizeof(entry_name),
+ WATCHDOG_NODEDIR "%s", entry->d_name);
+
+ /* realpath(entry_name, buf) unfortunately does a stat on
+ * target so we can't really use it to check if links stay
+ * within /dev without triggering e.g. AVC-logs (with
+ * SELinux policy that just allows stat within /dev).
+ * Without canonicalization that doesn't actually touch the
+ * filesystem easily available introduce some limitations
+ * for simplicity:
+ * - just simple path without '..'
+ * - just one level of symlinks (avoid e.g. loop-checking)
+ */
+ len = readlink(entry_name, buf, sizeof(buf) - 1);
+ if ((len < 1) ||
+ (len > sizeof(buf) - sizeof(WATCHDOG_NODEDIR) -1 - 1)) {
+ continue;
+ }
+ buf[len] = '\0';
+ if (buf[0] != '/') {
+ memmove(&buf[sizeof(WATCHDOG_NODEDIR)-1], buf, len+1);
+ memcpy(buf, WATCHDOG_NODEDIR, sizeof(WATCHDOG_NODEDIR)-1);
+ len += sizeof(WATCHDOG_NODEDIR)-1;
+ }
+ if (strstr(buf, "/../") ||
+ strncmp(WATCHDOG_NODEDIR, buf, sizeof(WATCHDOG_NODEDIR)-1)) {
+ continue;
+ } else {
+ /* just memorize to avoid statting the target - SELinux */
+ struct link_list_item *lli =
+ calloc(1, sizeof(struct link_list_item));
+
+ lli->dev_node = strdup(buf);
+ lli->link_name = strdup(entry_name);
+ lli->next = link_list;
+ link_list = lli;
+ }
+ }
+ }
- rewinddir(dp);
-
- while ((entry = readdir(dp))) {
- if (entry->d_type == DT_CHR) {
- struct stat statbuf;
-
- snprintf(entry_name, sizeof(entry_name),
- WATCHDOG_NODEDIR "%s", entry->d_name);
- if(!stat(entry_name, &statbuf) && S_ISCHR(statbuf.st_mode)) {
- int i;
-
- for (i=0; i<num_watchdogs; i++) {
- if (statbuf.st_rdev == watchdogs[i]) {
- int wdfd = watchdog_init_fd(entry_name, -1);
- struct watchdog_list_item *wdg =
- calloc(1, sizeof(struct watchdog_list_item));
- int len;
- struct link_list_item *tmp_list = NULL;
-
- wdg->dev = watchdogs[i];
- wdg->dev_node = strdup(entry_name);
- wdg->next = watchdog_list;
- watchdog_list = wdg;
- watchdog_list_items++;
-
- if (wdfd >= 0) {
- struct watchdog_info ident;
-
- ident.identity[0] = '\0';
- ioctl(wdfd, WDIOC_GETSUPPORT, &ident);
- watchdog_close_fd(wdfd, entry_name, true);
- if (ident.identity[0]) {
- wdg->dev_ident = strdup((char *) ident.identity);
- }
- }
-
- snprintf(entry_name, sizeof(entry_name),
- SYS_CHAR_DEV_DIR "/%d:%d/device/driver",
- major(watchdogs[i]), minor(watchdogs[i]));
- len = readlink(entry_name, buf, sizeof(buf) - 1);
- if (len > 0) {
- buf[len] = '\0';
- wdg->dev_driver = strdup(basename(buf));
- } else if ((wdg->dev_ident) &&
- (strcmp(wdg->dev_ident,
- "Software Watchdog") == 0)) {
- wdg->dev_driver = strdup("softdog");
- }
-
- /* create dupes if we have memorized links
- * to this node
- */
- for (tmp_list = link_list; tmp_list;
- tmp_list = tmp_list->next) {
- if (!strcmp(tmp_list->dev_node,
- wdg->dev_node)) {
- struct watchdog_list_item *dupe_wdg =
- calloc(1, sizeof(struct watchdog_list_item));
-
- /* as long as we never purge watchdog_list
- * there is no need to dupe strings
- */
- *dupe_wdg = *wdg;
- dupe_wdg->dev_node = strdup(tmp_list->link_name);
- dupe_wdg->next = watchdog_list;
- watchdog_list = dupe_wdg;
- watchdog_list_items++;
- }
- /* for performance reasons we could remove
- * the link_list entry
- */
- }
- break;
- }
- }
- }
- }
- }
+ rewinddir(dp);
+
+ while ((entry = readdir(dp))) {
+ if (entry->d_type == DT_CHR) {
+ struct stat statbuf;
+
+ snprintf(entry_name, sizeof(entry_name),
+ WATCHDOG_NODEDIR "%s", entry->d_name);
+ if(!stat(entry_name, &statbuf) && S_ISCHR(statbuf.st_mode) &&
+ is_watchdog(statbuf.st_rdev)) {
+
+ int wdfd = watchdog_init_fd(entry_name, -1);
+ struct watchdog_list_item *wdg =
+ calloc(1, sizeof(struct watchdog_list_item));
+ int len;
+ struct link_list_item *tmp_list = NULL;
+
+ wdg->dev = statbuf.st_rdev;
+ wdg->dev_node = strdup(entry_name);
+ wdg->next = watchdog_list;
+ watchdog_list = wdg;
+ watchdog_list_items++;
+
+ if (wdfd >= 0) {
+ struct watchdog_info ident;
+
+ ident.identity[0] = '\0';
+ ioctl(wdfd, WDIOC_GETSUPPORT, &ident);
+ watchdog_close_fd(wdfd, entry_name, true);
+ if (ident.identity[0]) {
+ wdg->dev_ident = strdup((char *) ident.identity);
+ }
+ }
+
+ snprintf(entry_name, sizeof(entry_name),
+ SYS_CHAR_DEV_DIR "/%d:%d/device/driver",
+ major(wdg->dev), minor(wdg->dev));
+ len = readlink(entry_name, buf, sizeof(buf) - 1);
+ if (len > 0) {
+ buf[len] = '\0';
+ wdg->dev_driver = strdup(basename(buf));
+ } else if ((wdg->dev_ident) &&
+ (strcmp(wdg->dev_ident,
+ "Software Watchdog") == 0)) {
+ wdg->dev_driver = strdup("softdog");
+ }
+
+ /* create dupes if we have memorized links
+ * to this node
+ */
+ for (tmp_list = link_list; tmp_list;
+ tmp_list = tmp_list->next) {
+ if (!strcmp(tmp_list->dev_node,
+ wdg->dev_node)) {
+ struct watchdog_list_item *dupe_wdg =
+ calloc(1, sizeof(struct watchdog_list_item));
+
+ /* as long as we never purge watchdog_list
+ * there is no need to dupe strings
+ */
+ *dupe_wdg = *wdg;
+ dupe_wdg->dev_node = strdup(tmp_list->link_name);
+ dupe_wdg->next = watchdog_list;
+ watchdog_list = dupe_wdg;
+ watchdog_list_items++;
+ }
+ /* for performance reasons we could remove
+ * the link_list entry
+ */
+ }
+ }
+ }
+ }
- closedir(dp);
- }
+ closedir(dp);
+ }
- /* cleanup link list */
- while (link_list) {
- struct link_list_item *tmp_list = link_list;
+ /* cleanup link list */
+ while (link_list) {
+ struct link_list_item *tmp_list = link_list;
- link_list = link_list->next;
- free(tmp_list->dev_node);
- free(tmp_list->link_name);
- free(tmp_list);
- }
+ link_list = link_list->next;
+ free(tmp_list->dev_node);
+ free(tmp_list->link_name);
+ free(tmp_list);
+ }
+}
+
+static void
+watchdog_checkbusy()
+{
+ DIR *dproc;
+ struct dirent *entry;
+
+ dproc = opendir("/proc");
+ if (!dproc) {
+ /* no proc directory to search through */
+ return;
+ }
+
+ while ((entry = readdir(dproc)) != NULL) {
+ pid_t local_pid;
+ char *leftover;
+ DIR *dpid;
+ char procpath[NAME_MAX+10] = { 0 };
+
+ if (entry->d_name[0] == '.') {
+ continue;
+ }
+
+ local_pid = strtol(entry->d_name, &leftover, 10);
+ if (leftover[0] != '\0')
+ continue;
+
+ snprintf(procpath, sizeof(procpath), "/proc/%s/fd", entry->d_name);
+ dpid = opendir(procpath);
+ if (!dpid) {
+ /* silently continue - might be just a race */
+ continue;
+ }
+ while ((entry = readdir(dpid)) != NULL) {
+ struct watchdog_list_item *wdg;
+ char entry_name[sizeof(procpath)+NAME_MAX+1] = { 0 };
+ char buf[NAME_MAX+1] = { 0 };
+ int len;
+
+ if (entry->d_type != DT_LNK) {
+ continue;
+ }
+ snprintf(entry_name, sizeof(entry_name),
+ "%s/%s", procpath, entry->d_name);
+ len = readlink(entry_name, buf, sizeof(buf) - 1);
+ if (len < 1) {
+ continue;
+ }
+ buf[len] = '\0';
+ for (wdg = watchdog_list; wdg != NULL; wdg = wdg->next) {
+ if (!strcmp(buf, wdg->dev_node)) {
+ char name[16];
+ FILE *file;
+
+ wdg->busy_pid = local_pid;
+ snprintf(procpath, sizeof(procpath), "/proc/%d/status", local_pid);
+ file = fopen(procpath, "r");
+ if (file) {
+ if (fscanf(file, "Name:\t%15[a-zA-Z0-9 _-]", name) == 1) {
+ wdg->busy_name = strdup(name);
+ }
+ fclose(file);
+ }
+ }
+ }
+ }
+ closedir(dpid);
+ }
+
+ closedir(dproc);
+
+ return;
}
int watchdog_info(void)
@@ -462,13 +560,23 @@ int watchdog_info(void)
int wdg_cnt = 0;
watchdog_populate_list();
+ watchdog_checkbusy();
printf("\nDiscovered %d watchdog devices:\n", watchdog_list_items);
for (wdg = watchdog_list; wdg != NULL; wdg = wdg->next) {
wdg_cnt++;
- printf("\n[%d] %s\nIdentity: %s\nDriver: %s\n",
+ if (wdg->busy_pid) {
+ printf("\n[%d] %s\nIdentity: Busy: PID %d (%s)\nDriver: %s\n",
wdg_cnt, wdg->dev_node,
- wdg->dev_ident?wdg->dev_ident:"Error: Check if hogged by e.g. sbd-daemon!",
+ wdg->busy_pid,
+ wdg->busy_name?wdg->busy_name:"<unknown>",
wdg->dev_driver?wdg->dev_driver:"<unknown>");
+ } else {
+ printf("\n[%d] %s\nIdentity: %s\nDriver: %s\n",
+ wdg_cnt, wdg->dev_node,
+ wdg->dev_ident?wdg->dev_ident:
+ "Error: device hogged via alias major/minor?",
+ wdg->dev_driver?wdg->dev_driver:"<unknown>");
+ }
if ((wdg->dev_driver) && (strcmp(wdg->dev_driver, "softdog") == 0)) {
printf("CAUTION: Not recommended for use with sbd.\n");
}
@@ -512,6 +620,7 @@ int watchdog_test(void)
watchdogdev, (int) timeout_watchdog);
if ((watchdog_init() < 0) || (watchdog_init_interval() < 0)) {
printf("Failed to initialize watchdog!!!\n");
+ watchdog_info();
return -1;
}
printf("\n");
--
1.8.3.1