diff options
Diffstat (limited to 'src/ipc.c')
| -rw-r--r-- | src/ipc.c | 238 |
1 files changed, 238 insertions, 0 deletions
diff --git a/src/ipc.c b/src/ipc.c new file mode 100644 index 00000000..a5ab342d --- /dev/null +++ b/src/ipc.c @@ -0,0 +1,238 @@ +#include "common.h" + +#include <sys/sem.h> +#include <sys/msg.h> +#include <sys/shm.h> + + +#ifndef SEMVMX +#define SEMVMX 32767 /* <= 32767 semaphore maximum value */ +#endif + +/* Some versions of libc only define IPC_INFO when __USE_GNU is defined. */ +#ifndef IPC_INFO +#define IPC_INFO 3 +#endif + +struct ipc_limits { + uint64_t shmmni; /* max number of segments */ + uint64_t shmmax; /* max segment size */ + uint64_t shmall; /* max total shared memory */ + uint64_t shmmin; /* min segment size */ + + int semmni; /* max number of arrays */ + int semmsl; /* max semaphores per array */ + int semmns; /* max semaphores system wide */ + int semopm; /* max ops per semop call */ + unsigned int semvmx; /* semaphore max value (constant) */ + + int msgmni; /* max queues system wide */ + size_t msgmax; /* max size of message */ + int msgmnb; /* default max size of queue */ +}; + +struct ipc_status { + int semusz; /* current number of arrays */ + int semaem; /* current semaphores system wide */ +}; + +/* + * The last arg of semctl is a union semun, but where is it defined? X/OPEN + * tells us to define it ourselves, but until recently Linux include files + * would also define it. + */ +#ifndef HAVE_UNION_SEMUN +/* according to X/OPEN we have to define it ourselves */ +union semun { + int val; + struct semid_ds *buf; + unsigned short int *array; + struct seminfo *__buf; +}; +#endif + +static inline int ipc_sem_get_limits(struct ipc_limits *lim) { + static procfile *ff = NULL; + static int error_shown = 0; + static char filename[FILENAME_MAX + 1] = ""; + + if(unlikely(!filename[0])) + snprintfz(filename, FILENAME_MAX, "%s/proc/sys/kernel/sem", global_host_prefix); + + if(unlikely(!ff)) { + ff = procfile_open(filename, NULL, PROCFILE_FLAG_DEFAULT); + if(unlikely(!ff)) { + if(unlikely(!error_shown)) { + error("IPC: Cannot open file '%s'.", filename); + error_shown = 1; + } + goto ipc; + } + } + + ff = procfile_readall(ff); + if(unlikely(!ff)) { + if(unlikely(!error_shown)) { + error("IPC: Cannot read file '%s'.", filename); + error_shown = 1; + } + goto ipc; + } + + if(procfile_lines(ff) >= 1 && procfile_linewords(ff, 0) >= 4) { + lim->semvmx = SEMVMX; + lim->semmsl = str2i(procfile_lineword(ff, 0, 0)); + lim->semmns = str2i(procfile_lineword(ff, 0, 1)); + lim->semopm = str2i(procfile_lineword(ff, 0, 2)); + lim->semmni = str2i(procfile_lineword(ff, 0, 3)); + return 0; + } + else { + if(unlikely(!error_shown)) { + error("IPC: Invalid content in file '%s'.", filename); + error_shown = 1; + } + goto ipc; + } + +ipc: + // cannot do it from the file + // query IPC + { + struct seminfo seminfo = {.semmni = 0}; + union semun arg = {.array = (ushort *) &seminfo}; + + if(unlikely(semctl(0, 0, IPC_INFO, arg) < 0)) { + error("IPC: Failed to read '%s' and request IPC_INFO with semctl().", filename); + goto error; + } + + lim->semvmx = SEMVMX; + lim->semmni = seminfo.semmni; + lim->semmsl = seminfo.semmsl; + lim->semmns = seminfo.semmns; + lim->semopm = seminfo.semopm; + return 0; + } + +error: + lim->semvmx = 0; + lim->semmni = 0; + lim->semmsl = 0; + lim->semmns = 0; + lim->semopm = 0; + return -1; +} + +/* +printf ("------ Semaphore Limits --------\n"); +printf ("max number of arrays = %d\n", limits.semmni); +printf ("max semaphores per array = %d\n", limits.semmsl); +printf ("max semaphores system wide = %d\n", limits.semmns); +printf ("max ops per semop call = %d\n", limits.semopm); +printf ("semaphore max value = %u\n", limits.semvmx); + +printf ("------ Semaphore Status --------\n"); +printf ("used arrays = %d\n", status.semusz); +printf ("allocated semaphores = %d\n", status.semaem); +*/ + +static inline int ipc_sem_get_status(struct ipc_status *st) { + struct seminfo seminfo; + union semun arg; + + arg.array = (ushort *) (void *) &seminfo; + + if(unlikely(semctl (0, 0, SEM_INFO, arg) < 0)) { + /* kernel not configured for semaphores */ + static int error_shown = 0; + if(unlikely(!error_shown)) { + error("IPC: kernel is not configured for semaphores"); + error_shown = 1; + } + st->semusz = 0; + st->semaem = 0; + return -1; + } + + st->semusz = seminfo.semusz; + st->semaem = seminfo.semaem; + return 0; +} + +int do_ipc(int update_every, usec_t dt) { + (void)dt; + + static int initialized = 0, read_limits_next = 0; + static struct ipc_limits limits; + static struct ipc_status status; + static RRDVAR *arrays_max = NULL, *semaphores_max = NULL; + static RRDSET *semaphores = NULL, *arrays = NULL; + + if(unlikely(!initialized)) { + initialized = 1; + + // make sure it works + if(ipc_sem_get_limits(&limits) == -1) { + error("unable to fetch semaphore limits"); + return 1; + } + + // make sure it works + if(ipc_sem_get_status(&status) == -1) { + error("unable to fetch semaphore statistics"); + return 1; + } + + arrays_max = rrdvar_custom_host_variable_create(&localhost, "ipc.semaphores.arrays.max"); + semaphores_max = rrdvar_custom_host_variable_create(&localhost, "ipc.semaphores.max"); + + if(arrays_max) rrdvar_custom_host_variable_set(arrays_max, limits.semmni); + if(semaphores_max) rrdvar_custom_host_variable_set(semaphores_max, limits.semmns); + + // create the charts + semaphores = rrdset_find("system.ipc_semaphores"); + if(!semaphores) { + semaphores = rrdset_create("system", "ipc_semaphores", NULL, "ipc semaphores", NULL, "IPC Semaphores", "semaphores", 1000, rrd_update_every, RRDSET_TYPE_AREA); + rrddim_add(semaphores, "semaphores", NULL, 1, 1, RRDDIM_ABSOLUTE); + } + + arrays = rrdset_find("system.ipc_semaphore_arrays"); + if(!arrays) { + arrays = rrdset_create("system", "ipc_semaphore_arrays", NULL, "ipc semaphores", NULL, "IPC Semaphore Arrays", "arrays", 1000, rrd_update_every, RRDSET_TYPE_AREA); + rrddim_add(arrays, "arrays", NULL, 1, 1, RRDDIM_ABSOLUTE); + } + } + + if(unlikely(read_limits_next < 0)) { + if(unlikely(ipc_sem_get_limits(&limits) == -1)) { + error("Unable to fetch semaphore limits."); + } + else { + if(arrays_max) rrdvar_custom_host_variable_set(arrays_max, limits.semmni); + if(semaphores_max) rrdvar_custom_host_variable_set(semaphores_max, limits.semmns); + + arrays->red = limits.semmni; + semaphores->red = limits.semmns; + + read_limits_next = 60 / update_every; + } + } + else + read_limits_next--; + + if(unlikely(ipc_sem_get_status(&status) == -1)) { + error("Unable to get semaphore statistics"); + return 0; + } + + if(semaphores->counter_done) rrdset_next(semaphores); + rrddim_set(semaphores, "semaphores", status.semaem); + rrdset_done(semaphores); + + if(arrays->counter_done) rrdset_next(arrays); + rrddim_set(arrays, "arrays", status.semusz); + rrdset_done(arrays); + + return 0; +} |