1 files changed, 58 insertions, 0 deletions
diff --git a/src/libnetdata/os/get_pid_max.c b/src/libnetdata/os/get_pid_max.c
new file mode 100644
index 000000000..45027961a
--- /dev/null
+++ b/src/libnetdata/os/get_pid_max.c
@@ -0,0 +1,58 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+#include "../libnetdata.h"
+
+pid_t pid_max = 32768;
+pid_t os_get_system_pid_max(void) {
+#if defined(OS_MACOS)
+
+    // As we currently do not know a solution to query pid_max from the os
+    // we use the number defined in bsd/sys/proc_internal.h in XNU sources
+    pid_max = 99999;
+    return pid_max;
+
+#elif defined(OS_FREEBSD)
+
+    int32_t tmp_pid_max;
+
+    if (unlikely(GETSYSCTL_BY_NAME("kern.pid_max", tmp_pid_max))) {
+        pid_max = 99999;
+        netdata_log_error("Assuming system's maximum pid is %d.", pid_max);
+    } else {
+        pid_max = tmp_pid_max;
+    }
+
+    return pid_max;
+
+#elif defined(OS_LINUX)
+
+    static char read = 0;
+    if(unlikely(read)) return pid_max;
+    read = 1;
+
+    char filename[FILENAME_MAX + 1];
+    snprintfz(filename, FILENAME_MAX, "%s/proc/sys/kernel/pid_max", netdata_configured_host_prefix?netdata_configured_host_prefix:"");
+
+    unsigned long long max = 0;
+    if(read_single_number_file(filename, &max) != 0) {
+        netdata_log_error("Cannot open file '%s'. Assuming system supports %d pids.", filename, pid_max);
+        return pid_max;
+    }
+
+    if(!max) {
+        netdata_log_error("Cannot parse file '%s'. Assuming system supports %d pids.", filename, pid_max);
+        return pid_max;
+    }
+
+    pid_max = (pid_t) max;
+    return pid_max;
+
+#else
+
+    // just a big default
+
+    pid_max = 4194304;
+    return pid_max;
+
+#endif
+}