#1428 in case of error, show the C syscall which caused it

11 files changed, 239 insertions, 162 deletions

diff --git a/psutil/_psutil_bsd.c b/psutil/_psutil_bsd.c
index dce157f5..073ff02d 100644
--- a/psutil/_psutil_bsd.c
+++ b/psutil/_psutil_bsd.c
@@ -804,7 +804,7 @@ psutil_users(PyObject *self, PyObject *args) {
 
     fp = fopen(_PATH_UTMP, "r");
     if (fp == NULL) {
-        PyErr_SetFromErrno(PyExc_OSError);
+        PyErr_SetFromErrnoWithFilename(PyExc_OSError, _PATH_UTMP);
         goto error;
     }
 
diff --git a/psutil/_psutil_common.c b/psutil/_psutil_common.c
index db1a0460..a4899487 100644
--- a/psutil/_psutil_common.c
+++ b/psutil/_psutil_common.c
@@ -7,8 +7,9 @@
  */
 
 #include <Python.h>
-#include <stdio.h>
-
+#ifdef _WIN32
+#include <windows.h>
+#endif
 
 // Global vars.
 int PSUTIL_DEBUG = 0;
@@ -51,6 +52,28 @@ NoSuchProcess(const char *msg) {
 
 
 /*
+ * Same as PyErr_SetFromErrno(0) but adds the syscall to the exception
+ * message.
+ */
+PyObject *
+PyErr_SetFromOSErrnoWithSyscall(const char *syscall) {
+    char fullmsg[1024];
+
+#ifdef _WIN32
+    sprintf(fullmsg, "originated from %s", syscall);
+    PyErr_SetFromWindowsErrWithFilename(GetLastError(), fullmsg);
+#else
+    PyObject *exc;
+    sprintf(fullmsg, "%s (originated from %s)", strerror(errno), syscall);
+    exc = PyObject_CallFunction(PyExc_OSError, "(is)", errno, fullmsg);
+    PyErr_SetObject(PyExc_OSError, exc);
+    Py_XDECREF(exc);
+#endif
+    return NULL;
+}
+
+
+/*
  * Set OSError(errno=EACCES, strerror="Permission denied") Python exception.
  * If msg != "" the exception message will change in accordance.
  */
diff --git a/psutil/_psutil_common.h b/psutil/_psutil_common.h
index e107166a..70698107 100644
--- a/psutil/_psutil_common.h
+++ b/psutil/_psutil_common.h
@@ -22,6 +22,7 @@ PyObject* PyUnicode_DecodeFSDefaultAndSize(char *s, Py_ssize_t size);
 
 PyObject* AccessDenied(const char *msg);
 PyObject* NoSuchProcess(const char *msg);
+PyObject* PyErr_SetFromOSErrnoWithSyscall(const char *syscall);
 
 PyObject* psutil_set_testing(PyObject *self, PyObject *args);
 void psutil_debug(const char* format, ...);
diff --git a/psutil/_psutil_linux.c b/psutil/_psutil_linux.c
index 5b7a56ad..be808633 100644
--- a/psutil/_psutil_linux.c
+++ b/psutil/_psutil_linux.c
@@ -535,7 +535,7 @@ psutil_net_if_duplex_speed(PyObject* self, PyObject* args) {
 
     sock = socket(AF_INET, SOCK_DGRAM, 0);
     if (sock == -1)
-        goto error;
+        return PyErr_SetFromOSErrnoWithSyscall("socket()");
     strncpy(ifr.ifr_name, nic_name, sizeof(ifr.ifr_name));
 
     // duplex and speed
@@ -558,20 +558,21 @@ psutil_net_if_duplex_speed(PyObject* self, PyObject* args) {
             speed = 0;
         }
         else {
+            PyErr_SetFromOSErrnoWithSyscall("ioctl(SIOCETHTOOL)");
             goto error;
         }
     }
 
-    close(sock);
     py_retlist = Py_BuildValue("[ii]", duplex, speed);
     if (!py_retlist)
         goto error;
+    close(sock);
     return py_retlist;
 
 error:
     if (sock != -1)
         close(sock);
-    return PyErr_SetFromErrno(PyExc_OSError);
+    return NULL;
 }
 
 
diff --git a/psutil/_psutil_osx.c b/psutil/_psutil_osx.c
index be08de55..1b98cc58 100644
--- a/psutil/_psutil_osx.c
+++ b/psutil/_psutil_osx.c
@@ -141,31 +141,22 @@ psutil_pids(PyObject *self, PyObject *args) {
     if (py_retlist == NULL)
         return NULL;
 
-    if (psutil_get_proc_list(&proclist, &num_processes) != 0) {
-        if (errno != 0) {
-            PyErr_SetFromErrno(PyExc_OSError);
-        }
-        else {
-            PyErr_SetString(PyExc_RuntimeError,
-                            "failed to retrieve process list");
-        }
+    if (psutil_get_proc_list(&proclist, &num_processes) != 0)
         goto error;
-    }
 
-    if (num_processes > 0) {
-        // save the address of proclist so we can free it later
-        orig_address = proclist;
-        for (idx = 0; idx < num_processes; idx++) {
-            py_pid = Py_BuildValue("i", proclist->kp_proc.p_pid);
-            if (! py_pid)
-                goto error;
-            if (PyList_Append(py_retlist, py_pid))
-                goto error;
-            Py_DECREF(py_pid);
-            proclist++;
-        }
-        free(orig_address);
+    // save the address of proclist so we can free it later
+    orig_address = proclist;
+    for (idx = 0; idx < num_processes; idx++) {
+        py_pid = Py_BuildValue("i", proclist->kp_proc.p_pid);
+        if (! py_pid)
+            goto error;
+        if (PyList_Append(py_retlist, py_pid))
+            goto error;
+        Py_DECREF(py_pid);
+        proclist++;
     }
+    free(orig_address);
+
     return py_retlist;
 
 error:
@@ -622,8 +613,10 @@ psutil_proc_memory_uss(PyObject *self, PyObject *args) {
         return NULL;
 
     len = sizeof(cpu_type);
-    if (sysctlbyname("sysctl.proc_cputype", &cpu_type, &len, NULL, 0) != 0)
-        return PyErr_SetFromErrno(PyExc_OSError);
+    if (sysctlbyname("sysctl.proc_cputype", &cpu_type, &len, NULL, 0) != 0) {
+        return PyErr_SetFromOSErrnoWithSyscall(
+            "sysctlbyname('sysctl.proc_cputype')");
+    }
 
     // Roughly based on libtop_update_vm_regions in
     // http://www.opensource.apple.com/source/top/top-100.1.2/libtop.c
@@ -863,12 +856,18 @@ psutil_cpu_freq(PyObject *self, PyObject *args) {
     int64_t max;
     size_t size = sizeof(int64_t);
 
-    if (sysctlbyname("hw.cpufrequency", &curr, &size, NULL, 0))
-        return PyErr_SetFromErrno(PyExc_OSError);
-    if (sysctlbyname("hw.cpufrequency_min", &min, &size, NULL, 0))
-        return PyErr_SetFromErrno(PyExc_OSError);
-    if (sysctlbyname("hw.cpufrequency_max", &max, &size, NULL, 0))
-        return PyErr_SetFromErrno(PyExc_OSError);
+    if (sysctlbyname("hw.cpufrequency", &curr, &size, NULL, 0)) {
+        return PyErr_SetFromOSErrnoWithSyscall(
+            "sysctlbyname('hw.cpufrequency')");
+    }
+    if (sysctlbyname("hw.cpufrequency_min", &min, &size, NULL, 0)) {
+        return PyErr_SetFromOSErrnoWithSyscall(
+            "sysctlbyname('hw.cpufrequency_min')");
+    }
+    if (sysctlbyname("hw.cpufrequency_max", &max, &size, NULL, 0)) {
+        return PyErr_SetFromOSErrnoWithSyscall(
+            "sysctlbyname('hw.cpufrequency_max')");
+    }
 
     return Py_BuildValue(
         "KKK",
@@ -1370,7 +1369,7 @@ psutil_proc_connections(PyObject *self, PyObject *args) {
 
                 // check for inet_ntop failures
                 if (errno != 0) {
-                    PyErr_SetFromErrno(PyExc_OSError);
+                    PyErr_SetFromOSErrnoWithSyscall("inet_ntop()");
                     goto error;
                 }
 
diff --git a/psutil/_psutil_windows.c b/psutil/_psutil_windows.c
index bcdc3e0b..7dc37ee1 100644
--- a/psutil/_psutil_windows.c
+++ b/psutil/_psutil_windows.c
@@ -286,7 +286,7 @@ psutil_proc_kill(PyObject *self, PyObject *args) {
         err = GetLastError();
         // See: https://github.com/giampaolo/psutil/issues/1099
         if (err != ERROR_ACCESS_DENIED) {
-            PyErr_SetFromWindowsErr(err);
+            PyErr_SetFromOSErrnoWithSyscall("TerminateProcess");
             CloseHandle(hProcess);
             return NULL;
         }
@@ -332,7 +332,7 @@ psutil_proc_wait(PyObject *self, PyObject *args) {
 
     // handle return code
     if (retVal == WAIT_FAILED) {
-        PyErr_SetFromWindowsErr(0);
+        PyErr_SetFromOSErrnoWithSyscall("WaitForSingleObject");
         CloseHandle(hProcess);
         return NULL;
     }
@@ -354,7 +354,7 @@ psutil_proc_wait(PyObject *self, PyObject *args) {
     // process is gone so we can get its process exit code. The PID
     // may still stick around though but we'll handle that from Python.
     if (GetExitCodeProcess(hProcess, &ExitCode) == 0) {
-        PyErr_SetFromWindowsErr(0);
+        PyErr_SetFromOSErrnoWithSyscall("GetExitCodeProcess");
         CloseHandle(hProcess);
         return NULL;
     }
@@ -652,7 +652,7 @@ psutil_proc_exe(PyObject *self, PyObject *args) {
 #if (_WIN32_WINNT >= 0x0600)  // Windows >= Vista
     memset(exe, 0, MAX_PATH);
     if (QueryFullProcessImageNameW(hProcess, 0, exe, &size) == 0) {
-        PyErr_SetFromWindowsErr(0);
+        PyErr_SetFromOSErrnoWithSyscall("QueryFullProcessImageNameW");
         CloseHandle(hProcess);
         return NULL;
     }
@@ -662,7 +662,7 @@ psutil_proc_exe(PyObject *self, PyObject *args) {
         if (GetLastError() == 0)
             PyErr_SetFromWindowsErr(ERROR_ACCESS_DENIED);
         else
-            PyErr_SetFromWindowsErr(0);
+            PyErr_SetFromOSErrnoWithSyscall("GetProcessImageFileNameW");
         CloseHandle(hProcess);
         return NULL;
     }
@@ -689,11 +689,11 @@ psutil_proc_name(PyObject *self, PyObject *args) {
         return NULL;
     hSnapShot = CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, pid);
     if (hSnapShot == INVALID_HANDLE_VALUE)
-        return PyErr_SetFromWindowsErr(0);
+        return PyErr_SetFromOSErrnoWithSyscall("CreateToolhelp32Snapshot");
     pentry.dwSize = sizeof(PROCESSENTRY32W);
     ok = Process32FirstW(hSnapShot, &pentry);
     if (! ok) {
-        PyErr_SetFromWindowsErr(0);
+        PyErr_SetFromOSErrnoWithSyscall("Process32FirstW");
         CloseHandle(hSnapShot);
         return NULL;
     }
@@ -944,7 +944,7 @@ psutil_per_cpu_times(PyObject *self, PyObject *args) {
     // allocates an array of _SYSTEM_PROCESSOR_PERFORMANCE_INFORMATION
     // structures, one per processor
     sppi = (_SYSTEM_PROCESSOR_PERFORMANCE_INFORMATION *) \
-           malloc(ncpus * sizeof(_SYSTEM_PROCESSOR_PERFORMANCE_INFORMATION));
+        malloc(ncpus * sizeof(_SYSTEM_PROCESSOR_PERFORMANCE_INFORMATION));
     if (sppi == NULL) {
         PyErr_NoMemory();
         goto error;
@@ -1046,7 +1046,7 @@ psutil_proc_suspend_or_resume(DWORD pid, int suspend) {
 
     hThreadSnap = CreateToolhelp32Snapshot(TH32CS_SNAPTHREAD, 0);
     if (hThreadSnap == INVALID_HANDLE_VALUE) {
-        PyErr_SetFromWindowsErr(0);
+        PyErr_SetFromOSErrnoWithSyscall("CreateToolhelp32Snapshot");
         return FALSE;
     }
 
@@ -1054,7 +1054,7 @@ psutil_proc_suspend_or_resume(DWORD pid, int suspend) {
     te32.dwSize = sizeof(THREADENTRY32);
 
     if (! Thread32First(hThreadSnap, &te32)) {
-        PyErr_SetFromWindowsErr(0);
+        PyErr_SetFromOSErrnoWithSyscall("Thread32First");
         CloseHandle(hThreadSnap);
         return FALSE;
     }
@@ -1067,14 +1067,14 @@ psutil_proc_suspend_or_resume(DWORD pid, int suspend) {
             hThread = OpenThread(THREAD_SUSPEND_RESUME, FALSE,
                                  te32.th32ThreadID);
             if (hThread == NULL) {
-                PyErr_SetFromWindowsErr(0);
+                PyErr_SetFromOSErrnoWithSyscall("OpenThread");
                 CloseHandle(hThread);
                 CloseHandle(hThreadSnap);
                 return FALSE;
             }
             if (suspend == 1) {
                 if (SuspendThread(hThread) == (DWORD) - 1) {
-                    PyErr_SetFromWindowsErr(0);
+                    PyErr_SetFromOSErrnoWithSyscall("SuspendThread");
                     CloseHandle(hThread);
                     CloseHandle(hThreadSnap);
                     return FALSE;
@@ -1082,7 +1082,7 @@ psutil_proc_suspend_or_resume(DWORD pid, int suspend) {
             }
             else {
                 if (ResumeThread(hThread) == (DWORD) - 1) {
-                    PyErr_SetFromWindowsErr(0);
+                    PyErr_SetFromOSErrnoWithSyscall("ResumeThread");
                     CloseHandle(hThread);
                     CloseHandle(hThreadSnap);
                     return FALSE;
@@ -1156,7 +1156,7 @@ psutil_proc_threads(PyObject *self, PyObject *args) {
 
     hThreadSnap = CreateToolhelp32Snapshot(TH32CS_SNAPTHREAD, 0);
     if (hThreadSnap == INVALID_HANDLE_VALUE) {
-        PyErr_SetFromWindowsErr(0);
+        PyErr_SetFromOSErrnoWithSyscall("CreateToolhelp32Snapshot");
         goto error;
     }
 
@@ -1164,7 +1164,7 @@ psutil_proc_threads(PyObject *self, PyObject *args) {
     te32.dwSize = sizeof(THREADENTRY32);
 
     if (! Thread32First(hThreadSnap, &te32)) {
-        PyErr_SetFromWindowsErr(0);
+        PyErr_SetFromOSErrnoWithSyscall("Thread32First");
         goto error;
     }
 
@@ -1184,7 +1184,7 @@ psutil_proc_threads(PyObject *self, PyObject *args) {
             rc = GetThreadTimes(hThread, &ftDummy, &ftDummy, &ftKernel,
                                 &ftUser);
             if (rc == 0) {
-                PyErr_SetFromWindowsErr(0);
+                PyErr_SetFromOSErrnoWithSyscall("GetThreadTimes");
                 goto error;
             }
 
@@ -1311,7 +1311,7 @@ psutil_proc_username(PyObject *self, PyObject *args) {
         return NULL;
 
     if (!OpenProcessToken(processHandle, TOKEN_QUERY, &tokenHandle)) {
-        PyErr_SetFromWindowsErr(0);
+        PyErr_SetFromOSErrnoWithSyscall("OpenProcessToken");
         goto error;
     }
 
@@ -1334,7 +1334,7 @@ psutil_proc_username(PyObject *self, PyObject *args) {
                 continue;
             }
             else {
-                PyErr_SetFromWindowsErr(0);
+                PyErr_SetFromOSErrnoWithSyscall("GetTokenInformation");
                 goto error;
             }
         }
@@ -1367,7 +1367,7 @@ psutil_proc_username(PyObject *self, PyObject *args) {
                 continue;
             }
             else {
-                PyErr_SetFromWindowsErr(0);
+                PyErr_SetFromOSErrnoWithSyscall("LookupAccountSidW");
                 goto error;
             }
         }
@@ -2570,7 +2570,7 @@ psutil_users(PyObject *self, PyObject *args) {
         return NULL;
 
     if (WTSEnumerateSessions(hServer, 0, 1, &sessions, &count) == 0) {
-        PyErr_SetFromWindowsErr(0);
+        PyErr_SetFromOSErrnoWithSyscall("WTSEnumerateSessions");
         goto error;
     }
 
@@ -2590,7 +2590,7 @@ psutil_users(PyObject *self, PyObject *args) {
         bytes = 0;
         if (WTSQuerySessionInformationW(hServer, sessionId, WTSUserName,
                                         &buffer_user, &bytes) == 0) {
-            PyErr_SetFromWindowsErr(0);
+            PyErr_SetFromOSErrnoWithSyscall("WTSQuerySessionInformationW");
             goto error;
         }
         if (bytes <= 2)
@@ -2600,7 +2600,7 @@ psutil_users(PyObject *self, PyObject *args) {
         bytes = 0;
         if (WTSQuerySessionInformation(hServer, sessionId, WTSClientAddress,
                                        &buffer_addr, &bytes) == 0) {
-            PyErr_SetFromWindowsErr(0);
+            PyErr_SetFromOSErrnoWithSyscall("WTSQuerySessionInformation");
             goto error;
         }
 
@@ -2630,6 +2630,7 @@ psutil_users(PyObject *self, PyObject *args) {
                 sizeof(station_info),
                 &returnLen))
         {
+            PyErr_SetFromOSErrnoWithSyscall("WinStationQueryInformationW");
             goto error;
         }
 
@@ -3295,7 +3296,8 @@ psutil_cpu_stats(PyObject *self, PyObject *args) {
         ncpus * sizeof(_SYSTEM_PERFORMANCE_INFORMATION),
         NULL);
     if (status != 0) {
-        PyErr_SetFromWindowsErr(0);
+        PyErr_SetFromOSErrnoWithSyscall(
+            "NtQuerySystemInformation(SYSTEM_PERFORMANCE_INFORMATION)");
         goto error;
     }
 
@@ -3313,7 +3315,8 @@ psutil_cpu_stats(PyObject *self, PyObject *args) {
         ncpus * sizeof(SYSTEM_INTERRUPT_INFORMATION),
         NULL);
     if (status != 0) {
-        PyErr_SetFromWindowsErr(0);
+        PyErr_SetFromOSErrnoWithSyscall(
+            "NtQuerySystemInformation(SYSTEM_INTERRUPT_INFORMATION)");
         goto error;
     }
     for (i = 0; i < ncpus; i++) {
@@ -3334,7 +3337,8 @@ psutil_cpu_stats(PyObject *self, PyObject *args) {
         ncpus * sizeof(_SYSTEM_PROCESSOR_PERFORMANCE_INFORMATION),
         NULL);
     if (status != 0) {
-        PyErr_SetFromWindowsErr(0);
+        PyErr_SetFromOSErrnoWithSyscall(
+            "NtQuerySystemInformation(SYSTEM_PROCESSOR_PERFORMANCE_INFORMATION)");
         goto error;
     }
 
diff --git a/psutil/arch/freebsd/specific.c b/psutil/arch/freebsd/specific.c
index 93bf51ff..26b80242 100644
--- a/psutil/arch/freebsd/specific.c
+++ b/psutil/arch/freebsd/specific.c
@@ -54,7 +54,7 @@ psutil_kinfo_proc(const pid_t pid, struct kinfo_proc *proc) {
 
     size = sizeof(struct kinfo_proc);
     if (sysctl((int *)mib, 4, proc, &size, NULL, 0) == -1) {
-        PyErr_SetFromErrno(PyExc_OSError);
+        PyErr_SetFromOSErrnoWithSyscall("sysctl(KERN_PROC_PID)");
         return -1;
     }
 
@@ -209,7 +209,7 @@ static char
     size = argmax;
     if (sysctl(mib, 4, procargs, &size, NULL, 0) == -1) {
         free(procargs);
-        PyErr_SetFromErrno(PyExc_OSError);
+        PyErr_SetFromOSErrnoWithSyscall("sysctl(KERN_PROC_ARGS)");
         return NULL;
     }
 
@@ -287,10 +287,13 @@ psutil_proc_exe(PyObject *self, PyObject *args) {
     error = sysctl(mib, 4, pathname, &size, NULL, 0);
     if (error == -1) {
         // see: https://github.com/giampaolo/psutil/issues/907
-        if (errno == ENOENT)
+        if (errno == ENOENT) {
             return PyUnicode_DecodeFSDefault("");
-        else
-            return PyErr_SetFromErrno(PyExc_OSError);
+        }
+        else {
+            return \
+                PyErr_SetFromOSErrnoWithSyscall("sysctl(KERN_PROC_PATHNAME)");
+        }
     }
     if (size == 0 || strlen(pathname) == 0) {
         ret = psutil_pid_exists(pid);
@@ -350,7 +353,7 @@ psutil_proc_threads(PyObject *self, PyObject *args) {
     size = 0;
     error = sysctl(mib, 4, NULL, &size, NULL, 0);
     if (error == -1) {
-        PyErr_SetFromErrno(PyExc_OSError);
+        PyErr_SetFromOSErrnoWithSyscall("sysctl(KERN_PROC_INC_THREAD)");
         goto error;
     }
     if (size == 0) {
@@ -366,7 +369,7 @@ psutil_proc_threads(PyObject *self, PyObject *args) {
 
     error = sysctl(mib, 4, kip, &size, NULL, 0);
     if (error == -1) {
-        PyErr_SetFromErrno(PyExc_OSError);
+        PyErr_SetFromOSErrnoWithSyscall("sysctl(KERN_PROC_INC_THREAD)");
         goto error;
     }
     if (size == 0) {
@@ -447,26 +450,38 @@ psutil_virtual_mem(PyObject *self, PyObject *args) {
 #endif
     size_t buffers_size = sizeof(buffers);
 
-    if (sysctlbyname("hw.physmem", &total, &size, NULL, 0))
-        goto error;
-    if (sysctlbyname("vm.stats.vm.v_active_count", &active, &size, NULL, 0))
-        goto error;
-    if (sysctlbyname("vm.stats.vm.v_inactive_count",
-                     &inactive, &size, NULL, 0))
-        goto error;
-    if (sysctlbyname("vm.stats.vm.v_wire_count", &wired, &size, NULL, 0))
-        goto error;
+    if (sysctlbyname("hw.physmem", &total, &size, NULL, 0)) {
+        return PyErr_SetFromOSErrnoWithSyscall("sysctlbyname('hw.physmem')");
+    }
+    if (sysctlbyname("vm.stats.vm.v_active_count", &active, &size, NULL, 0)) {
+        return PyErr_SetFromOSErrnoWithSyscall(
+            "sysctlbyname('vm.stats.vm.v_active_count')");
+    }
+    if (sysctlbyname("vm.stats.vm.v_inactive_count", &inactive, &size, NULL, 0))
+    {
+        return PyErr_SetFromOSErrnoWithSyscall(
+            "sysctlbyname('vm.stats.vm.v_inactive_count')");
+    }
+    if (sysctlbyname("vm.stats.vm.v_wire_count", &wired, &size, NULL, 0)) {
+        return PyErr_SetFromOSErrnoWithSyscall(
+            "sysctlbyname('vm.stats.vm.v_wire_count')");
+    }
     // https://github.com/giampaolo/psutil/issues/997
-    if (sysctlbyname("vm.stats.vm.v_cache_count", &cached, &size, NULL, 0))
+    if (sysctlbyname("vm.stats.vm.v_cache_count", &cached, &size, NULL, 0)) {
         cached = 0;
-    if (sysctlbyname("vm.stats.vm.v_free_count", &free, &size, NULL, 0))
-        goto error;
-    if (sysctlbyname("vfs.bufspace", &buffers, &buffers_size, NULL, 0))
-        goto error;
+    }
+    if (sysctlbyname("vm.stats.vm.v_free_count", &free, &size, NULL, 0)) {
+        return PyErr_SetFromOSErrnoWithSyscall(
+            "sysctlbyname('vm.stats.vm.v_free_count')");
+    }
+    if (sysctlbyname("vfs.bufspace", &buffers, &buffers_size, NULL, 0)) {
+        return PyErr_SetFromOSErrnoWithSyscall("sysctlbyname('vfs.bufspace')");
+    }
 
     size = sizeof(vm);
-    if (sysctl(mib, 2, &vm, &size, NULL, 0) != 0)
-        goto error;
+    if (sysctl(mib, 2, &vm, &size, NULL, 0) != 0) {
+        return PyErr_SetFromOSErrnoWithSyscall("sysctl(CTL_VM | VM_METER)");
+    }
 
     return Py_BuildValue("KKKKKKKK",
         (unsigned long long) total,
@@ -478,9 +493,6 @@ psutil_virtual_mem(PyObject *self, PyObject *args) {
         (unsigned long long) buffers,
         (unsigned long long) (vm.t_vmshr + vm.t_rmshr) * pagesize  // shared
     );
-
-error:
-    return PyErr_SetFromErrno(PyExc_OSError);
 }
 
 
@@ -491,6 +503,7 @@ psutil_swap_mem(PyObject *self, PyObject *args) {
     struct kvm_swap kvmsw[1];
     unsigned int swapin, swapout, nodein, nodeout;
     size_t size = sizeof(unsigned int);
+    int pagesize;
 
     kd = kvm_open(NULL, _PATH_DEVNULL, NULL, O_RDONLY, "kvm_open failed");
     if (kd == NULL) {
@@ -507,16 +520,28 @@ psutil_swap_mem(PyObject *self, PyObject *args) {
 
     kvm_close(kd);
 
-    if (sysctlbyname("vm.stats.vm.v_swapin", &swapin, &size, NULL, 0) == -1)
-        goto error;
-    if (sysctlbyname("vm.stats.vm.v_swapout", &swapout, &size, NULL, 0) == -1)
-        goto error;
-    if (sysctlbyname("vm.stats.vm.v_vnodein", &nodein, &size, NULL, 0) == -1)
-        goto error;
-    if (sysctlbyname("vm.stats.vm.v_vnodeout", &nodeout, &size, NULL, 0) == -1)
-        goto error;
+    if (sysctlbyname("vm.stats.vm.v_swapin", &swapin, &size, NULL, 0) == -1) {
+        return PyErr_SetFromOSErrnoWithSyscall(
+            "sysctlbyname('vm.stats.vm.v_swapin)'");
+    }
+    if (sysctlbyname("vm.stats.vm.v_swapout", &swapout, &size, NULL, 0) == -1){
+        return PyErr_SetFromOSErrnoWithSyscall(
+            "sysctlbyname('vm.stats.vm.v_swapout)'");
+    }
+    if (sysctlbyname("vm.stats.vm.v_vnodein", &nodein, &size, NULL, 0) == -1) {
+        return PyErr_SetFromOSErrnoWithSyscall(
+            "sysctlbyname('vm.stats.vm.v_vnodein)'");
+    }
+    if (sysctlbyname("vm.stats.vm.v_vnodeout", &nodeout, &size, NULL, 0) == -1) {
+        return PyErr_SetFromOSErrnoWithSyscall(
+            "sysctlbyname('vm.stats.vm.v_vnodeout)'");
+    }
 
-    int pagesize = getpagesize();
+    pagesize = getpagesize();
+    if (pagesize <= 0) {
+        PyErr_SetString(PyExc_ValueError, "invalid getpagesize()");
+        return NULL;
+    }
 
     return Py_BuildValue(
         "(KKKII)",
@@ -527,9 +552,6 @@ psutil_swap_mem(PyObject *self, PyObject *args) {
         swapin + swapout,  // swap in
         nodein + nodeout  // swap out
     );
-
-error:
-    return PyErr_SetFromErrno(PyExc_OSError);
 }
 
 
@@ -629,7 +651,8 @@ psutil_per_cpu_times(PyObject *self, PyObject *args) {
     size = sizeof(maxcpus);
     if (sysctlbyname("kern.smp.maxcpus", &maxcpus, &size, NULL, 0) < 0) {
         Py_DECREF(py_retlist);
-        return PyErr_SetFromErrno(PyExc_OSError);
+        return PyErr_SetFromOSErrnoWithSyscall(
+            "sysctlbyname('kern.smp.maxcpus')");
     }
     long cpu_time[maxcpus][CPUSTATES];
 
@@ -638,14 +661,14 @@ psutil_per_cpu_times(PyObject *self, PyObject *args) {
     mib[1] = HW_NCPU;
     len = sizeof(ncpu);
     if (sysctl(mib, 2, &ncpu, &len, NULL, 0) == -1) {
-        PyErr_SetFromErrno(PyExc_OSError);
+        PyErr_SetFromOSErrnoWithSyscall("sysctl(HW_NCPU)");
         goto error;
     }
 
     // per-cpu info
     size = sizeof(cpu_time);
     if (sysctlbyname("kern.cp_times", &cpu_time, &size, NULL, 0) == -1) {
-        PyErr_SetFromErrno(PyExc_OSError);
+        PyErr_SetFromOSErrnoWithSyscall("sysctlbyname('kern.smp.maxcpus')");
         goto error;
     }
 
@@ -960,16 +983,26 @@ psutil_cpu_stats(PyObject *self, PyObject *args) {
     unsigned int v_swtch;
     size_t size = sizeof(v_soft);
 
-    if (sysctlbyname("vm.stats.sys.v_soft", &v_soft, &size, NULL, 0))
-        goto error;
-    if (sysctlbyname("vm.stats.sys.v_intr", &v_intr, &size, NULL, 0))
-        goto error;
-    if (sysctlbyname("vm.stats.sys.v_syscall", &v_syscall, &size, NULL, 0))
-        goto error;
-    if (sysctlbyname("vm.stats.sys.v_trap", &v_trap, &size, NULL, 0))
-        goto error;
-    if (sysctlbyname("vm.stats.sys.v_swtch", &v_swtch, &size, NULL, 0))
-        goto error;
+    if (sysctlbyname("vm.stats.sys.v_soft", &v_soft, &size, NULL, 0)) {
+        return PyErr_SetFromOSErrnoWithSyscall(
+            "sysctlbyname('vm.stats.sys.v_soft')");
+    }
+    if (sysctlbyname("vm.stats.sys.v_intr", &v_intr, &size, NULL, 0)) {
+        return PyErr_SetFromOSErrnoWithSyscall(
+            "sysctlbyname('vm.stats.sys.v_intr')");
+    }
+    if (sysctlbyname("vm.stats.sys.v_syscall", &v_syscall, &size, NULL, 0)) {
+        return PyErr_SetFromOSErrnoWithSyscall(
+            "sysctlbyname('vm.stats.sys.v_syscall')");
+    }
+    if (sysctlbyname("vm.stats.sys.v_trap", &v_trap, &size, NULL, 0)) {
+        return PyErr_SetFromOSErrnoWithSyscall(
+            "sysctlbyname('vm.stats.sys.v_trap')");
+    }
+    if (sysctlbyname("vm.stats.sys.v_swtch", &v_swtch, &size, NULL, 0)) {
+        return PyErr_SetFromOSErrnoWithSyscall(
+            "sysctlbyname('vm.stats.sys.v_swtch')");
+    }
 
     return Py_BuildValue(
         "IIIII",
@@ -979,9 +1012,6 @@ psutil_cpu_stats(PyObject *self, PyObject *args) {
         v_syscall,  // syscalls
         v_trap  // traps
     );
-
-error:
-    return PyErr_SetFromErrno(PyExc_OSError);
 }
 
 
diff --git a/psutil/arch/osx/process_info.c b/psutil/arch/osx/process_info.c
index e5ecbaed..484254d5 100644
--- a/psutil/arch/osx/process_info.c
+++ b/psutil/arch/osx/process_info.c
@@ -59,8 +59,10 @@ psutil_get_proc_list(kinfo_proc **procList, size_t *procCount) {
      */
     while (lim-- > 0) {
         size = 0;
-        if (sysctl((int *)mib3, 3, NULL, &size, NULL, 0) == -1)
-            return errno;
+        if (sysctl((int *)mib3, 3, NULL, &size, NULL, 0) == -1) {
+            PyErr_SetFromOSErrnoWithSyscall("sysctl(KERN_PROC_ALL)");
+            return 1;
+        }
         size2 = size + (size >> 3);  // add some
         if (size2 > size) {
             ptr = malloc(size2);
@@ -72,22 +74,32 @@ psutil_get_proc_list(kinfo_proc **procList, size_t *procCount) {
         else {
             ptr = malloc(size);
         }
-        if (ptr == NULL)
-            return ENOMEM;
+        if (ptr == NULL) {
+            PyErr_NoMemory();
+            return 1;
+        }
 
         if (sysctl((int *)mib3, 3, ptr, &size, NULL, 0) == -1) {
             err = errno;
             free(ptr);
-            if (err != ENOMEM)
-                return err;
+            if (err != ENOMEM) {
+                PyErr_SetFromOSErrnoWithSyscall("sysctl(KERN_PROC_ALL)");
+                return 1;
+            }
         }
         else {
             *procList = (kinfo_proc *)ptr;
             *procCount = size / sizeof(kinfo_proc);
-            return 0;
+            if (procCount <= 0) {
+                PyErr_Format(PyExc_RuntimeError, "no PIDs found");
+                return 1;
+            }
+            return 0;  // success
         }
     }
-    return ENOMEM;
+
+    PyErr_Format(PyExc_RuntimeError, "couldn't collect PIDs list");
+    return 1;
 }
 
 
@@ -100,6 +112,7 @@ psutil_get_argmax() {
 
     if (sysctl(mib, 2, &argmax, &size, NULL, 0) == 0)
         return argmax;
+    PyErr_SetFromOSErrnoWithSyscall("sysctl(KERN_ARGMAX)");
     return 0;
 }
 
@@ -125,10 +138,8 @@ psutil_get_cmdline(long pid) {
 
     // read argmax and allocate memory for argument space.
     argmax = psutil_get_argmax();
-    if (! argmax) {
-        PyErr_SetFromErrno(PyExc_OSError);
+    if (! argmax)
         goto error;
-    }
 
     procargs = (char *)malloc(argmax);
     if (NULL == procargs) {
@@ -219,10 +230,8 @@ psutil_get_environ(long pid) {
 
     // read argmax and allocate memory for argument space.
     argmax = psutil_get_argmax();
-    if (! argmax) {
-        PyErr_SetFromErrno(PyExc_OSError);
+    if (! argmax)
         goto error;
-    }
 
     procargs = (char *)malloc(argmax);
     if (NULL == procargs) {
diff --git a/psutil/arch/windows/process_info.c b/psutil/arch/windows/process_info.c
index 9a698e42..5e0b9421 100644
--- a/psutil/arch/windows/process_info.c
+++ b/psutil/arch/windows/process_info.c
@@ -227,7 +227,10 @@ psutil_check_phandle(HANDLE hProcess, DWORD pid) {
     else if (ret == 0)
         return NoSuchProcess("");
     else if (ret == -1)
-        return PyErr_SetFromWindowsErr(0);
+        if (GetLastError() == ERROR_ACCESS_DENIED)
+            return PyErr_SetFromWindowsErr(0);
+        else
+            return PyErr_SetFromOSErrnoWithSyscall("OpenProcess");
     else  // -2
         return NULL;
 }
@@ -358,7 +361,7 @@ psutil_pid_is_running(DWORD pid) {
         // Be strict and raise an exception; the caller is supposed
         // to take -1 into account.
         else {
-            PyErr_SetFromWindowsErr(err);
+            PyErr_SetFromOSErrnoWithSyscall("OpenProcess(PROCESS_VM_READ)");
             return -1;
         }
     }
@@ -392,7 +395,7 @@ psutil_pid_is_running(DWORD pid) {
             return 1;
         }
         else {
-            PyErr_SetFromWindowsErr(err);
+            PyErr_SetFromOSErrnoWithSyscall("GetExitCodeProcess");
             return -1;
         }
     }
@@ -406,7 +409,7 @@ psutil_get_process_region_size(HANDLE hProcess, LPCVOID src, SIZE_T *psize) {
     MEMORY_BASIC_INFORMATION info;
 
     if (!VirtualQueryEx(hProcess, src, &info, sizeof(info))) {
-        PyErr_SetFromWindowsErr(0);
+        PyErr_SetFromOSErrnoWithSyscall("VirtualQueryEx");
         return -1;
     }
 
@@ -488,7 +491,8 @@ psutil_get_process_data(long pid,
             sizeof(LPVOID),
             NULL)))
     {
-        PyErr_SetFromWindowsErr(0);
+        PyErr_SetFromOSErrnoWithSyscall(
+            "NtQueryInformationProcess(ProcessWow64Information)");
         goto error;
     }
 
@@ -499,7 +503,7 @@ psutil_get_process_data(long pid,
 
         // read PEB
         if (!ReadProcessMemory(hProcess, ppeb32, &peb32, sizeof(peb32), NULL)) {
-            PyErr_SetFromWindowsErr(0);
+            PyErr_SetFromOSErrnoWithSyscall("ReadProcessMemory");
             goto error;
         }
 
@@ -509,7 +513,8 @@ psutil_get_process_data(long pid,
                               &procParameters32,
                               sizeof(procParameters32),
                               NULL)) {
-            PyErr_SetFromWindowsErr(0);
+            PyErr_SetFromOSErrnoWithSyscall(
+                "ReadProcessMemory(ProcessParameters)");
             goto error;
         }
 
@@ -530,8 +535,8 @@ psutil_get_process_data(long pid,
 #else
     /* 32 bit case.  Check if the target is also 32 bit. */
     if (!IsWow64Process(GetCurrentProcess(), &weAreWow64) ||
-        !IsWow64Process(hProcess, &theyAreWow64)) {
-        PyErr_SetFromWindowsErr(0);
+            !IsWow64Process(hProcess, &theyAreWow64)) {
+        PyErr_SetFromOSErrnoWithSyscall("IsWow64Process");
         goto error;
     }
 
@@ -570,7 +575,8 @@ psutil_get_process_data(long pid,
                 sizeof(pbi64),
                 NULL)))
         {
-            PyErr_SetFromWindowsErr(0);
+            PyErr_SetFromOSErrnoWithSyscall(
+                "NtWow64QueryInformationProcess64(ProcessBasicInformation)");
             goto error;
         }
 
@@ -582,7 +588,7 @@ psutil_get_process_data(long pid,
                sizeof(peb64),
                NULL)))
         {
-            PyErr_SetFromWindowsErr(0);
+            PyErr_SetFromOSErrnoWithSyscall("NtWow64ReadVirtualMemory64");
             goto error;
         }
 
@@ -594,7 +600,8 @@ psutil_get_process_data(long pid,
                 sizeof(procParameters64),
                 NULL)))
         {
-            PyErr_SetFromWindowsErr(0);
+            PyErr_SetFromOSErrnoWithSyscall(
+                "NtWow64ReadVirtualMemory64(ProcessParameters)");
             goto error;
         }
 
@@ -626,7 +633,8 @@ psutil_get_process_data(long pid,
                 sizeof(pbi),
                 NULL)))
         {
-            PyErr_SetFromWindowsErr(0);
+            PyErr_SetFromOSErrnoWithSyscall(
+                "NtQueryInformationProcess(ProcessBasicInformation)");
             goto error;
         }
 
@@ -636,7 +644,7 @@ psutil_get_process_data(long pid,
                                &peb,
                                sizeof(peb),
                                NULL)) {
-            PyErr_SetFromWindowsErr(0);
+            PyErr_SetFromOSErrnoWithSyscall("ReadProcessMemory");
             goto error;
         }
 
@@ -646,7 +654,8 @@ psutil_get_process_data(long pid,
                                &procParameters,
                                sizeof(procParameters),
                                NULL)) {
-            PyErr_SetFromWindowsErr(0);
+            PyErr_SetFromOSErrnoWithSyscall(
+                "ReadProcessMemory(ProcessParameters)");
             goto error;
         }
 
@@ -678,7 +687,6 @@ psutil_get_process_data(long pid,
     }
 
     buffer = calloc(size + 2, 1);
-
     if (buffer == NULL) {
         PyErr_NoMemory();
         goto error;
@@ -693,13 +701,13 @@ psutil_get_process_data(long pid,
                 size,
                 NULL)))
         {
-            PyErr_SetFromWindowsErr(0);
+            PyErr_SetFromOSErrnoWithSyscall("NtWow64ReadVirtualMemory64");
             goto error;
         }
     } else
 #endif
     if (!ReadProcessMemory(hProcess, src, buffer, size, NULL)) {
-        PyErr_SetFromWindowsErr(0);
+        PyErr_SetFromOSErrnoWithSyscall("ReadProcessMemory");
         goto error;
     }
 
@@ -751,7 +759,7 @@ psutil_get_cmdline_data(long pid, WCHAR **pdata, SIZE_T *psize) {
         &ret_length
     );
     if (! NT_SUCCESS(status)) {
-        PyErr_SetFromWindowsErr(0);
+        PyErr_SetFromOSErrnoWithSyscall("NtQueryInformationProcess");
         goto error;
     }
 
@@ -820,7 +828,7 @@ psutil_get_cmdline(long pid, int use_peb) {
     // attempt to parse the command line using Win32 API
     szArglist = CommandLineToArgvW(data, &nArgs);
     if (szArglist == NULL) {
-        PyErr_SetFromWindowsErr(0);
+        PyErr_SetFromOSErrnoWithSyscall("CommandLineToArgvW");
         goto out;
     }
 
diff --git a/psutil/arch/windows/services.c b/psutil/arch/windows/services.c
index 62a12861..92458494 100644
--- a/psutil/arch/windows/services.c
+++ b/psutil/arch/windows/services.c
@@ -24,13 +24,13 @@ psutil_get_service_handler(char *service_name, DWORD scm_access, DWORD access)
 
     sc = OpenSCManager(NULL, NULL, scm_access);
     if (sc == NULL) {
-        PyErr_SetFromWindowsErr(0);
+        PyErr_SetFromOSErrnoWithSyscall("OpenSCManager");
         return NULL;
     }
     hService = OpenService(sc, service_name, access);
     if (hService == NULL) {
+        PyErr_SetFromOSErrnoWithSyscall("OpenService");
         CloseServiceHandle(sc);
-        PyErr_SetFromWindowsErr(0);
         return NULL;
     }
     CloseServiceHandle(sc);
@@ -113,7 +113,7 @@ psutil_winservice_enumerate(PyObject *self, PyObject *args) {
 
     sc = OpenSCManager(NULL, NULL, SC_MANAGER_ENUMERATE_SERVICE);
     if (sc == NULL) {
-        PyErr_SetFromWindowsErr(0);
+        PyErr_SetFromOSErrnoWithSyscall("OpenSCManager");
         return NULL;
     }
 
@@ -213,13 +213,13 @@ psutil_winservice_query_config(PyObject *self, PyObject *args) {
     bytesNeeded = 0;
     QueryServiceConfigW(hService, NULL, 0, &bytesNeeded);
     if (GetLastError() != ERROR_INSUFFICIENT_BUFFER) {
-        PyErr_SetFromWindowsErr(0);
+        PyErr_SetFromOSErrnoWithSyscall("QueryServiceConfigW");
         goto error;
     }
     qsc = (QUERY_SERVICE_CONFIGW *)malloc(bytesNeeded);
     ok = QueryServiceConfigW(hService, qsc, bytesNeeded, &bytesNeeded);
     if (ok == 0) {
-        PyErr_SetFromWindowsErr(0);
+        PyErr_SetFromOSErrnoWithSyscall("QueryServiceConfigW");
         goto error;
     }
 
@@ -307,7 +307,7 @@ psutil_winservice_query_status(PyObject *self, PyObject *args) {
         return Py_BuildValue("s", "");
     }
     if (GetLastError() != ERROR_INSUFFICIENT_BUFFER) {
-        PyErr_SetFromWindowsErr(0);
+        PyErr_SetFromOSErrnoWithSyscall("QueryServiceStatusEx");
         goto error;
     }
     ssp = (SERVICE_STATUS_PROCESS *)HeapAlloc(
@@ -321,7 +321,7 @@ psutil_winservice_query_status(PyObject *self, PyObject *args) {
     ok = QueryServiceStatusEx(hService, SC_STATUS_PROCESS_INFO, (LPBYTE)ssp,
                               bytesNeeded, &bytesNeeded);
     if (ok == 0) {
-        PyErr_SetFromWindowsErr(0);
+        PyErr_SetFromOSErrnoWithSyscall("QueryServiceStatusEx");
         goto error;
     }
 
@@ -381,7 +381,7 @@ psutil_winservice_query_descr(PyObject *self, PyObject *args) {
         return Py_BuildValue("s", "");
     }
     if (GetLastError() != ERROR_INSUFFICIENT_BUFFER) {
-        PyErr_SetFromWindowsErr(0);
+        PyErr_SetFromOSErrnoWithSyscall("QueryServiceConfig2W");
         goto error;
     }
 
@@ -389,7 +389,7 @@ psutil_winservice_query_descr(PyObject *self, PyObject *args) {
     ok = QueryServiceConfig2W(hService, SERVICE_CONFIG_DESCRIPTION,
                               (LPBYTE)scd, bytesNeeded, &bytesNeeded);
     if (ok == 0) {
-        PyErr_SetFromWindowsErr(0);
+        PyErr_SetFromOSErrnoWithSyscall("QueryServiceConfig2W");
         goto error;
     }
 
@@ -435,7 +435,7 @@ psutil_winservice_start(PyObject *self, PyObject *args) {
     }
     ok = StartService(hService, 0, NULL);
     if (ok == 0) {
-        PyErr_SetFromWindowsErr(0);
+        PyErr_SetFromOSErrnoWithSyscall("StartService");
         goto error;
     }
 
@@ -471,7 +471,7 @@ psutil_winservice_stop(PyObject *self, PyObject *args) {
     ok = ControlService(hService, SERVICE_CONTROL_STOP, &ssp);
     Py_END_ALLOW_THREADS
     if (ok == 0) {
-        PyErr_SetFromWindowsErr(0);
+        PyErr_SetFromOSErrnoWithSyscall("ControlService");
         goto error;
     }
 
diff --git a/psutil/tests/test_system.py b/psutil/tests/test_system.py
index 7cc678f0..b0b7e4f0 100755
--- a/psutil/tests/test_system.py
+++ b/psutil/tests/test_system.py
@@ -766,7 +766,9 @@ class TestSystemAPIs(unittest.TestCase):
 
         ls = psutil.cpu_freq(percpu=True)
         if TRAVIS and not ls:
-            return
+            raise self.skipTest("skipped on Travis")
+        if FREEBSD and not ls:
+            raise self.skipTest("returns empty list on FreeBSD")
 
         assert ls, ls
         check_ls([psutil.cpu_freq(percpu=False)])