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Tidy and improve code for session discovery

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1. Add brackets round if bodies.
2. Use common os_calls/thread_calls functions where available and add
   new ones for:
     g_file_seek_rel_end()
     g_map_file_shared()
     g_unmap_file_shared()
     g_sleep_secs() [because usleep() can error for argument >= 1M]
     g_ftruncate()
     tc_mutex_timed_lock()
     tc_shared_mutex_create()
3. Separate declarations and initialisations.
4. Make macros for sesshm_try_lock() etc cleaner.

Also some minor bugfixes:

1. Fix bug in sesshm_try_lock() which begins "return 0".
2. The return value of pthread_mutex_init() in sesshm_create_new_shm()
   was ignored.  (No longer relevant because tc_shared_mutex_create() is
   now used.)
3. sesshm_map() set g_shm_mapping and returned a value.  (No longer
   relevant because using g_map_file_shared() it is simple enough not to
   need a function.)
This commit is contained in:
Ben Cohen 2017-07-17 18:38:13 +01:00
parent e450230deb
commit 6a13daea30
5 changed files with 253 additions and 123 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

77
common/os_calls.c
View File

@ -60,6 +60,7 @@
#include <pwd.h>
#include <time.h>
#include <grp.h>
#include <sys/mman.h>
#endif
#include <stdlib.h>
@ -1474,6 +1475,17 @@ g_sleep(int msecs)
#endif
}
/*****************************************************************************/
void
g_sleep_secs(int secs)
{
#if defined(_WIN32)
Sleep(secs * 1000);
#else
sleep(secs);
#endif
}
/*****************************************************************************/
int
g_sck_last_error_would_block(int sck)
@ -2105,6 +2117,17 @@ g_memcmp(const void *s1, const void *s2, int len)
return memcmp(s1, s2, len);
}
/*****************************************************************************/
int
g_ftruncate(int fd, int length)
{
#if defined(_WIN32)
return -1;
#else
return ftruncate(fd, length);
#endif
}
/*****************************************************************************/
/* returns -1 on error, else return handle or file descriptor */
int
@ -2246,6 +2269,31 @@ g_file_seek(int fd, int offset)
#endif
}
/*****************************************************************************/
/* move file pointer relative to end of file,
* returns offset on success, -1 on failure */
int
g_file_seek_rel_end(int fd, int offset)
{
#if defined(_WIN32)
int rv;
rv = (int)SetFilePointer((HANDLE)fd, offset, 0, FILE_END);
if (rv == (int)INVALID_SET_FILE_POINTER)
{
return -1;
}
else
{
return rv;
}
#else
return (int)lseek(fd, offset, SEEK_END);
#endif
}
/*****************************************************************************/
/* do a write lock on a file */
/* return boolean */
@ -3044,6 +3092,35 @@ g_get_proc_address(long lib, const char *name)
#endif
}
/*****************************************************************************/
/* does not work in win32 */
void *
g_map_file_shared(int fd, int length)
{
void *mapped;
mapped = mmap(NULL,
length,
PROT_READ|PROT_WRITE,
MAP_SHARED,
fd,
0);
/* MAP_FAILED != NULL but mmap() will not return 0 unless MAP_FIXED is
* specified. */
if (mapped == MAP_FAILED)
mapped = NULL;
return mapped;
}
/*****************************************************************************/
/* does not work in win32 */
int
g_unmap_file_shared(void *mapped, int length)
{
return munmap(mapped, length);
}
/*****************************************************************************/
/* does not work in win32 */
int

5
common/os_calls.h
View File

@ -86,6 +86,7 @@ int g_sck_can_recv(int sck, int millis);
int g_sck_select(int sck1, int sck2);
void g_write_ip_address(int rcv_sck, char* ip_address, int bytes);
void g_sleep(int msecs);
void g_sleep_secs(int secs);
tintptr g_create_wait_obj(const char *name);
tintptr g_create_wait_obj_from_socket(tintptr socket, int write);
void g_delete_wait_obj_from_socket(tintptr wait_obj);
@ -98,6 +99,7 @@ int g_obj_wait(tintptr* read_objs, int rcount, tintptr* write_objs,
void g_random(char* data, int len);
int g_abs(int i);
int g_memcmp(const void* s1, const void* s2, int len);
int g_ftruncate(int fd, int length);
int g_file_open(const char* file_name);
int g_file_open_ex(const char *file_name, int aread, int awrite,
int acreate, int atrunc);
@ -105,6 +107,7 @@ int g_file_close(int fd);
int g_file_read(int fd, char* ptr, int len);
int g_file_write(int fd, const char *ptr, int len);
int g_file_seek(int fd, int offset);
int g_file_seek_rel_end(int fd, int offset);
int g_file_lock(int fd, int start, int len);
int g_chmod_hex(const char* filename, int flags);
int g_chown(const char* name, int uid, int gid);
@ -142,6 +145,8 @@ int g_strtrim(char* str, int trim_flags);
long g_load_library(char* in);
int g_free_library(long lib);
void* g_get_proc_address(long lib, const char* name);
void* g_map_file_shared(int fd, int length);
int g_unmap_file_shared(void *mapped, int length);
int g_system(char* aexec);
char* g_get_strerror(void);
int g_get_errno(void);

44
common/thread_calls.c
View File

@ -112,6 +112,34 @@ tc_mutex_create(void)
#endif
}
/*****************************************************************************/
int
tc_shared_mutex_create(tbus mutex)
{
#if defined(_WIN32)
/* Not implemented yet */
return 1;
#else
pthread_mutexattr_t mutexattr;
int rc;
rc = pthread_mutexattr_init(&mutexattr);
if (rc != 0)
{
return 1;
}
rc = pthread_mutexattr_setpshared(&mutexattr, PTHREAD_PROCESS_SHARED);
if (rc != 0)
{
return 1;
}
rc = pthread_mutex_init((pthread_mutex_t *)mutex, &mutexattr);
return rc;
#endif
}
/*****************************************************************************/
void
tc_mutex_delete(tbus mutex)
@ -140,6 +168,22 @@ tc_mutex_lock(tbus mutex)
#endif
}
/*****************************************************************************/
int
tc_mutex_timed_lock(tbus mutex, int timeout_ms)
{
#if defined(_WIN32)
WaitForSingleObject((HANDLE)mutex, timeout_ms);
return 0;
#else
struct timespec timeout;
timeout.tv_sec = timeout_ms / 1000;
timeout.tv_nsec = ((long)timeout_ms % 1000) * 1000;
return pthread_mutex_timedlock((pthread_mutex_t *)mutex, &timeout);
#endif
}
/*****************************************************************************/
int
tc_mutex_unlock(tbus mutex)

4
common/thread_calls.h
View File

@ -31,11 +31,15 @@ int
tc_threadid_equal(tbus tid1, tbus tid2);
tbus
tc_mutex_create(void);
int
tc_shared_mutex_create(tbus mutex);
void
tc_mutex_delete(tbus mutex);
int
tc_mutex_lock(tbus mutex);
int
tc_mutex_timed_lock(tbus mutex, int timeout_ms);
int
tc_mutex_unlock(tbus mutex);
tbus
tc_sem_create(int init_count);

236
sesman/session.c
View File

@ -40,17 +40,6 @@
#include <sys/prctl.h>
#endif
#include <sys/mman.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <pthread.h>
#include <string.h>
#include <errno.h>
#include "sesman.h"
#include "libscp_types.h"
#include "xauth.h"
@ -121,16 +110,29 @@ dumpItemsToString(struct list *self, char *outstr, int len)
*
*/
static int
#ifdef DEBUG_SESSION_LOCK
sesshm_lock(const char *caller_func, int caller_line)
#else
sesshm_lock()
#endif
{
#ifdef DONT_USE_SHM
return 0;
#else
int rc = pthread_mutex_lock(&g_shm_mapping->mutex);
int rc;
#ifdef DEBUG_SESSION_LOCK
log_message(LOG_LEVEL_DEBUG,
"pid %d tid %d: %s() called from %s at line %d",
g_getpid(), (int)tc_get_threadid(), __func__,
caller_func, caller_line);
#endif
rc = tc_mutex_lock((tbus)&g_shm_mapping->mutex);
if (rc != 0)
{
log_message(LOG_LEVEL_ERROR,
"pthread_mutex_lock() failed (%d)", errno);
"tc_mutex_lock() failed (%d)", g_get_errno());
}
return rc;
#endif
@ -146,18 +148,26 @@ sesshm_lock()
*/
#ifndef DONT_USE_SHM
static int
#ifdef DEBUG_SESSION_LOCK
sesshm_try_lock(const char *caller_func, int caller_line)
#else
sesshm_try_lock()
#endif
{
return 0;
struct timespec timeout;
timeout.tv_sec = 1;
timeout.tv_nsec = 0;
int rc;
int rc = pthread_mutex_timedlock(&g_shm_mapping->mutex, &timeout);
#ifdef DEBUG_SESSION_LOCK
log_message(LOG_LEVEL_DEBUG,
"pid %d tid %d: %s() called from %s at line %d",
g_getpid(), (int)tc_get_threadid(), __func__,
caller_func, caller_line);
#endif
rc = tc_mutex_timed_lock((tbus)&g_shm_mapping->mutex, 1 * 1000);
if (rc != 0)
{
log_message(LOG_LEVEL_ERROR,
"pthread_mutex_timedlock() failed (%d)", errno);
"tc_mutex_timed_lock() failed (%d)", g_get_errno());
}
return rc;
}
@ -172,16 +182,29 @@ sesshm_try_lock()
*
*/
static int
#ifdef DEBUG_SESSION_LOCK
sesshm_unlock(const char *caller_func, int caller_line)
#else
sesshm_unlock()
#endif
{
#ifdef DONT_USE_SHM
return 0;
#else
int rc = pthread_mutex_unlock(&g_shm_mapping->mutex);
int rc;
#ifdef DEBUG_SESSION_LOCK
log_message(LOG_LEVEL_DEBUG,
"pid %d tid %d: %s() called from %s at line %d",
g_getpid(), (int)tc_get_threadid(), __func__,
caller_func, caller_line);
#endif
rc = tc_mutex_unlock((tbus) &g_shm_mapping->mutex);
if (rc != 0)
{
log_message(LOG_LEVEL_ERROR,
"pthread_mutex_unlock() failed (%d)", errno);
"tc_mutex_unlock() failed (%d)", g_get_errno());
}
return rc;
#endif
@ -189,50 +212,9 @@ sesshm_unlock()
#ifdef DEBUG_SESSION_LOCK
#define sesshm_try_lock() \
({ \
log_message(LOG_LEVEL_DEBUG, \
"pid %d tid %d: sesshm_try_lock() called from %s at line %d", \
getpid(), (int)tc_get_threadid(), __func__, __LINE__); \
sesshm_try_lock(); \
})
#define sesshm_lock() \
{ \
log_message(LOG_LEVEL_DEBUG, \
"pid %d tid %d: sesshm_lock() called from %s at line %d", \
getpid(), (int)tc_get_threadid(), __func__, __LINE__); \
sesshm_lock(); \
}
#define sesshm_unlock() \
{ \
log_message(LOG_LEVEL_DEBUG, \
"pid %d tid %d: sesshm_unlock() called from %s at line %d", \
getpid(), (int)tc_get_threadid(), __func__, __LINE__); \
sesshm_unlock(); \
}
#endif
/******************************************************************************/
/**
*
* @brief map the file fd into memory using mmap
* @return pointer to the mapping
*
*/
#ifndef DONT_USE_SHM
static struct session_shared_data *
sesshm_map(int fd)
{
g_shm_mapping = (struct session_shared_data *) mmap(NULL,
SESMAN_SHAREDMEM_LENGTH,
PROT_READ|PROT_WRITE,
MAP_SHARED,
fd,
0);
close(fd);
return g_shm_mapping;
}
#define sesshm_try_lock() sesshm_try_lock(__func__, __LINE__)
#define sesshm_lock() sesshm_lock(__func__, __LINE__)
#define sesshm_unlock() sesshm_unlock(__func__, __LINE__)
#endif
@ -247,13 +229,19 @@ sesshm_map(int fd)
static void *
sesshm_thread(void *arg)
{
int pid = g_getpid();
int pid;
pid = g_getpid();
while (g_sesshm_thread_going)
{
sleep(SESMAN_SHAREDMEM_HEARTBEAT_INTERVAL);
g_sleep_secs(SESMAN_SHAREDMEM_HEARTBEAT_INTERVAL);
if (g_pid == pid)
{
int current_time;
struct session_chain *tmp;
struct session_chain *prev;
/* Daemon process
* Check that the file hasn't been hijacked by a new daemon
* process and that the heartbeat hasn't timed out for the
@ -267,9 +255,9 @@ sesshm_thread(void *arg)
exit(1);
}
int current_time = g_time1();
struct session_chain *tmp = g_sessions;
struct session_chain *prev = 0;
current_time = g_time1();
tmp = g_sessions;
prev = 0;
while (tmp != 0)
{
if (tmp->item == 0)
@ -364,54 +352,42 @@ sesshm_create_new_shm()
log_message(LOG_LEVEL_INFO, "Creating shm file %s",
SESMAN_SHAREDMEM_FILENAME);
unlink(SESMAN_SHAREDMEM_FILENAME);
fd = open(SESMAN_SHAREDMEM_FILENAME, O_CREAT|O_RDWR, 00600);
g_file_delete(SESMAN_SHAREDMEM_FILENAME);
fd = g_file_open_ex(SESMAN_SHAREDMEM_FILENAME, 1, 1, 1, 0);
if (fd == -1)
{
log_message(LOG_LEVEL_ERROR, "open() failed (%d)", errno);
log_message(LOG_LEVEL_ERROR, "open() failed (%d)", g_get_errno());
return 1;
}
rc = ftruncate(fd, SESMAN_SHAREDMEM_LENGTH);
rc = g_ftruncate(fd, SESMAN_SHAREDMEM_LENGTH);
if (rc != 0)
{
log_message(LOG_LEVEL_ERROR, "truncate() failed (%d)", errno);
log_message(LOG_LEVEL_ERROR, "truncate() failed (%d)", g_get_errno());
return 2;
}
/* Map it into memory */
g_shm_mapping = sesshm_map(fd);
if (g_shm_mapping == MAP_FAILED)
g_shm_mapping = ((struct session_shared_data *)
g_map_file_shared(fd, SESMAN_SHAREDMEM_LENGTH));
g_file_close(fd);
if (g_shm_mapping == NULL)
{
log_message(LOG_LEVEL_ERROR, "mmap() failed (%d)", errno);
log_message(LOG_LEVEL_ERROR, "mmap() failed (%d)", g_get_errno());
return 3;
}
/* Initalise mutex */
pthread_mutexattr_t mutexattr;
rc = pthread_mutexattr_init(&mutexattr);
rc = tc_shared_mutex_create((tbus) &g_shm_mapping->mutex);
if (rc != 0)
{
log_message(LOG_LEVEL_ERROR, "pthread_mutexattr_init() failed (%d)",
errno);
return 4;
}
rc = pthread_mutexattr_setpshared(&mutexattr, PTHREAD_PROCESS_SHARED);
if (rc != 0)
{
log_message(LOG_LEVEL_ERROR,
"pthread_mutexattr_setpshared() failed (%d)", errno);
return 5;
}
pthread_mutex_init(&g_shm_mapping->mutex, &mutexattr);
if (rc != 0)
{
log_message(LOG_LEVEL_ERROR, "pthread_mutex_init() failed (%d)", errno);
log_message(LOG_LEVEL_ERROR, "tc_shared_mutex_create() failed (%d)",
g_get_errno());
return 6;
}
/* Initialise data */
sesshm_lock();
strncpy(g_shm_mapping->tag, SESMAN_SHAREDMEM_TAG,
g_strncpy(g_shm_mapping->tag, SESMAN_SHAREDMEM_TAG,
sizeof(g_shm_mapping->tag));
g_shm_mapping->data_format_version = SESMAN_SHAREDMEM_FORMAT_VERSION;
g_shm_mapping->max_sessions = SESMAN_SHAREDMEM_MAX_SESSIONS;
@ -441,26 +417,27 @@ sesshm_try_open_existing_shm()
int rc;
int fd;
int i;
off_t end;
char tag[SESMAN_SHAREDMEM_TAG_LENGTH];
log_message(LOG_LEVEL_INFO, "Looking for existing shm file %s",
SESMAN_SHAREDMEM_FILENAME);
/* Does the shared file already exist? */
fd = open(SESMAN_SHAREDMEM_FILENAME, O_RDWR);
fd = g_file_open_ex(SESMAN_SHAREDMEM_FILENAME, 1, 1, 0, 0);
if (fd == -1)
{
log_message(LOG_LEVEL_ERROR, "open() failed (%d)", errno);
log_message(LOG_LEVEL_ERROR, "open() failed (%d)", g_get_errno());
return 1;
}
char tag[SESMAN_SHAREDMEM_TAG_LENGTH];
rc = read(fd, tag, SESMAN_SHAREDMEM_TAG_LENGTH);
rc = g_file_read(fd, tag, SESMAN_SHAREDMEM_TAG_LENGTH);
if (rc != SESMAN_SHAREDMEM_TAG_LENGTH)
{
log_message(LOG_LEVEL_ERROR, "read() failed (%d)", errno);
log_message(LOG_LEVEL_ERROR, "read() failed (%d)", g_get_errno());
return 2;
}
if (strncmp(tag, SESMAN_SHAREDMEM_TAG, SESMAN_SHAREDMEM_TAG_LENGTH))
if (g_strncmp(tag, SESMAN_SHAREDMEM_TAG, SESMAN_SHAREDMEM_TAG_LENGTH))
{
log_message(LOG_LEVEL_ERROR, "tag is wrong file shm file %s",
SESMAN_SHAREDMEM_FILENAME);
@ -469,25 +446,27 @@ sesshm_try_open_existing_shm()
}
/* Is it the right size? */
off_t end = lseek(fd, 0, SEEK_END);
end = g_file_seek_rel_end(fd, 0);
if (end != SESMAN_SHAREDMEM_LENGTH)
{
log_message(LOG_LEVEL_ERROR, "shm file %s has wrong length",
SESMAN_SHAREDMEM_FILENAME);
return 4;
}
rc = lseek(fd, 0, SEEK_SET);
rc = g_file_seek(fd, 0);
if (rc != 0)
{
log_message(LOG_LEVEL_ERROR, "seek() failed (%d)", errno);
log_message(LOG_LEVEL_ERROR, "seek() failed (%d)", g_get_errno());
return 5;
}
/* Map it into memory */
g_shm_mapping = sesshm_map(fd);
if (g_shm_mapping == MAP_FAILED)
g_shm_mapping = ((struct session_shared_data *)
g_map_file_shared(fd, SESMAN_SHAREDMEM_LENGTH));
g_file_close(fd);
if (g_shm_mapping == NULL)
{
log_message(LOG_LEVEL_ERROR, "mmap() failed (%d)", errno);
log_message(LOG_LEVEL_ERROR, "mmap() failed (%d)", g_get_errno());
return 6;
}
@ -496,7 +475,8 @@ sesshm_try_open_existing_shm()
rc = sesshm_try_lock();
if (rc)
{
log_message(LOG_LEVEL_ERROR, "sesshm_try_lock() failed (%d)", errno);
log_message(LOG_LEVEL_ERROR, "sesshm_try_lock() failed (%d)",
g_get_errno());
// XXX Should we exit(1) here instead?
return 7;
}
@ -504,7 +484,7 @@ sesshm_try_open_existing_shm()
if (g_shm_mapping->data_format_version != SESMAN_SHAREDMEM_FORMAT_VERSION)
{
sesshm_unlock();
log_message(LOG_LEVEL_ERROR, "wrong data version (%d)", errno);
log_message(LOG_LEVEL_ERROR, "wrong data version (%d)", g_get_errno());
// XXX Should we exit(1) here instead?
return 8;
}
@ -514,8 +494,11 @@ sesshm_try_open_existing_shm()
{
if (g_shm_mapping->sessions[i].shm_is_allocated)
{
struct session_chain *temp =
(struct session_chain *)g_malloc(sizeof(struct session_chain), 0);
struct session_chain *temp;
temp =
(struct session_chain *)g_malloc(sizeof(struct session_chain),
0);
temp->item = &g_shm_mapping->sessions[i];
temp->next = g_sessions;
g_sessions = temp;
@ -551,11 +534,15 @@ session_init_shared()
/* If it's not okay then create it */
if (rc != 0)
{
rc = sesshm_create_new_shm();
}
/* Start polling thread */
if (rc == 0)
{
tc_thread_create(sesshm_thread, 0);
}
return rc;
#endif
@ -575,16 +562,22 @@ session_close_shared()
#ifdef DONT_USE_SHM
return 0;
#else
int rc;
g_sesshm_thread_going = 0;
sesshm_lock();
if (g_shm_mapping->daemon_pid == g_getpid())
{
g_shm_mapping->daemon_pid = -1;
}
sesshm_unlock();
int rc = munmap(g_shm_mapping, SESMAN_SHAREDMEM_LENGTH);
rc = g_unmap_file_shared(g_shm_mapping, SESMAN_SHAREDMEM_LENGTH);
if (rc != 0)
{
return 1;
}
return 0;
#endif
@ -610,7 +603,7 @@ alloc_session_item()
{
if (!g_shm_mapping->sessions[i].shm_is_allocated)
{
memset(&g_shm_mapping->sessions[i],
g_memset(&g_shm_mapping->sessions[i],
0,
sizeof(g_shm_mapping->sessions[i]));
g_shm_mapping->sessions[i].shm_is_allocated = 1;
@ -636,17 +629,24 @@ alloc_session_item()
static int
validate_session_item_ptr(struct session_item *item)
{
char *start = (char *) &g_shm_mapping->sessions[0];
int diff = (char *) item - start;
int size = sizeof(g_shm_mapping->sessions[0]);
int valid = (diff % size == 0
char *start;
int diff;
int size;
int valid;
start = (char *) &g_shm_mapping->sessions[0];
diff = (char *) item - start;
size = sizeof(g_shm_mapping->sessions[0]);
valid = (diff % size == 0
&& diff >= 0
&& (diff / size < g_shm_mapping->max_sessions));
if (!valid)
{
log_message(LOG_LEVEL_ALWAYS,
"validate_session_item_ptr: bad pointer %p",
item);
}
return valid;
}