added option -t to test if it has the permissions to read /proc/PID/io files

diff --git a/src/apps_plugin.c b/src/apps_plugin.c
index fcfe92a56ecfc737cab25cb81e45c57b388ee878..f5c25c7366ecb27364654a8fbd55e39b1d12435d 100644 (file)
--- a/src/apps_plugin.c
+++ b/src/apps_plugin.c
@@ -2902,6 +2902,22 @@ static void send_charts_updates_to_netdata(struct target *root, const char *type
 // ----------------------------------------------------------------------------
 // parse command line arguments
 
+int check_proc_1_io() {
+    int ret = 0;
+
+    procfile *ff = procfile_open("/proc/1/io", NULL, PROCFILE_FLAG_NO_ERROR_ON_FILE_IO);
+    if(!ff) goto cleanup;
+
+    ff = procfile_readall(ff);
+    if(!ff) goto cleanup;
+
+    ret = 1;
+
+cleanup:
+    procfile_close(ff);
+    return ret;
+}
+
 static void parse_args(int argc, char **argv)
 {
     int i, freq = 0;
@@ -2921,6 +2937,15 @@ static void parse_args(int argc, char **argv)
             exit(0);
         }
 
+        if(strcmp("test-permissions", argv[i]) == 0 || strcmp("-t", argv[i]) == 0) {
+            if(!check_proc_1_io()) {
+                perror("Tried to read /proc/1/io and it failed");
+                exit(1);
+            }
+            printf("OK\n");
+            exit(0);
+        }
+
         if(strcmp("debug", argv[i]) == 0) {
             debug = 1;
             // debug_flags = 0xffffffff;
@@ -3093,8 +3118,6 @@ int main(int argc, char **argv) {
     // set the name for logging
     program_name = "apps.plugin";
 
-    info("started on pid %d", getpid());
-
     // disable syslog for apps.plugin
     error_log_syslog = 0;
 
@@ -3136,27 +3159,27 @@ int main(int argc, char **argv) {
 
     parse_args(argc, argv);
 
-    if(!check_capabilities()) {
-        if(!am_i_running_as_root()) {
-            uid_t uid = getuid(), euid = geteuid();
+    if(!check_capabilities() && !am_i_running_as_root() && !check_proc_1_io()) {
+        uid_t uid = getuid(), euid = geteuid();
 #ifdef HAVE_CAPABILITY
-            error("apps.plugin should either run as root (now running with uid %u, euid %u) or have special capabilities. "
-                          "Without these, apps.plugin cannot report disk I/O utilization of other processes. "
-                          "To enable capabilities run: sudo setcap cap_dac_read_search,cap_sys_ptrace+ep %s; "
-                          "To enable setuid to root run: sudo chown root %s; sudo chmod 4755 %s; "
-                  , uid, euid, argv[0], argv[0], argv[0]
-            );
+        error("apps.plugin should either run as root (now running with uid %u, euid %u) or have special capabilities. "
+                      "Without these, apps.plugin cannot report disk I/O utilization of other processes. "
+                      "To enable capabilities run: sudo setcap cap_dac_read_search,cap_sys_ptrace+ep %s; "
+                      "To enable setuid to root run: sudo chown root %s; sudo chmod 4755 %s; "
+              , uid, euid, argv[0], argv[0], argv[0]
+        );
 #else
-            error("apps.plugin should either run as root (now running with uid %u, euid %u) or have special capabilities. "
-                          "Without these, apps.plugin cannot report disk I/O utilization of other processes. "
-                          "Your system does not support capabilities. "
-                          "To enable setuid to root run: sudo chown root %s; sudo chmod 4755 %s; "
-                  , uid, euid, argv[0], argv[0]
-            );
+        error("apps.plugin should either run as root (now running with uid %u, euid %u) or have special capabilities. "
+                      "Without these, apps.plugin cannot report disk I/O utilization of other processes. "
+                      "Your system does not support capabilities. "
+                      "To enable setuid to root run: sudo chown root %s; sudo chmod 4755 %s; "
+              , uid, euid, argv[0], argv[0]
+        );
 #endif
-        }
     }
 
+    info("started on pid %d", getpid());
+
     all_pids_sortlist = callocz(sizeof(pid_t), (size_t)pid_max);
     all_pids          = callocz(sizeof(struct pid_stat *), (size_t) pid_max);
 

diff --git a/src/procfile.c b/src/procfile.c
index dc4a5409b46a54a6efeaa09d23f681118866a30c..3a89e83539c75371db0f7c8c77565463d746a772 100644 (file)
--- a/src/procfile.c
+++ b/src/procfile.c
@@ -128,6 +128,8 @@ static inline void pflines_free(pflines *fl) {
 // The procfile
 
 void procfile_close(procfile *ff) {
+    if(unlikely(!ff)) return;
+
     debug(D_PROCFILE, PF_PREFIX ": Closing file '%s'", procfile_filename(ff));
 
     if(likely(ff->lines)) pflines_free(ff->lines);