#include <stddef.h>
#include <limits.h>
#include <sys/param.h>
+#include <stdbool.h>
#include "gcc-compat.h"
-#include "string.h"
+#include "str.h"
#include "log.h"
#include "gcc-compat.h"
-#include "error.h"
+#include "err.h"
#include "ipc.h"
-#if (defined(__GNUC__) && defined(__i386__))
-#define get16bits(d) (*((const uint16_t *) (d)))
-#else
-#define get16bits(d) ((((uint32_t)(((const uint8_t *)(d))[1])) << 8)\
- +(uint32_t)(((const uint8_t *)(d))[0]) )
-#endif
-
-/*
- * SuperFastHash, by Paul Hsieh.
- * http://www.azillionmonkeys.com/qed/hash.html
- */
-static uint32_t super_fast_hash(const uint8_t *data, uint32_t len, uint32_t hash)
-{
- uint32_t tmp;
- int rem = len & 3;
-
- len >>= 2;
-
- for (;len > 0; len--) {
- hash += get16bits (data);
- tmp = (get16bits (data+2) << 11) ^ hash;
- hash = (hash << 16) ^ tmp;
- data += 2*sizeof (uint16_t);
- hash += hash >> 11;
- }
-
- /* Handle end cases */
- switch (rem) {
- case 3:
- hash += get16bits (data);
- hash ^= hash << 16;
- hash ^= data[sizeof (uint16_t)] << 18;
- hash += hash >> 11;
- break;
- case 2:
- hash += get16bits (data);
- hash ^= hash << 11;
- hash += hash >> 17;
- break;
- case 1:
- hash += *data;
- hash ^= hash << 10;
- hash += hash >> 1;
- }
- /* Force "avalanching" of final 127 bits */
- hash ^= hash << 3;
- hash += hash >> 5;
- hash ^= hash << 4;
- hash += hash >> 17;
- hash ^= hash << 25;
- hash += hash >> 6;
- return hash;
-}
-
-/*
- * Return the canonical absolute name of a given file name.
- *
- * Slightly modified version of glibc's realpath, Copyright (C)
- * 1996-2002,2004,2005,2006,2008 Free Software Foundation, Inc.
- *
- * A canonical name does not contain any `.', `..' components nor any repeated
- * path separators ('/') or symlinks. All path components must exist. The
- * result is malloc'd and must be freed by the caller.
- */
-static int dss_realpath(const char *name, char **resolved_path)
+static key_t get_key(const char *config_file)
{
- char *rpath = NULL, *dest, *extra_buf = NULL;
- const char *start, *end, *rpath_limit;
- long int path_max;
- int ret, num_links = 0;
+ key_t ret;
- if (name[0] == '\0') {
- /*
- * As per Single Unix Specification V2 we must return an error
- * if the name argument points to an empty string.
- */
- ret = -ERRNO_TO_DSS_ERROR(ENOENT);
- goto error;
- }
-#ifdef PATH_MAX
- path_max = PATH_MAX;
-#else
+ assert(config_file);
+ ret = ftok(config_file, 'D');
+ if (ret >= 0)
+ return ret;
/*
- * From realpath(3): Asking pathconf(3) does not really help, since on
- * the one hand POSIX warns that the result of pathconf(3) may be
- * huge and unsuitable for mallocing memory. And on the other hand
- * pathconf(3) may return -1 to signify that PATH_MAX is not bounded.
+ * This happens if the user did not specify a config file, and the
+ * default config file does not exist. Another (unlikely) possibility
+ * is that the config file was removed between startup and this call.
+ * We don't care about these corner cases too much and just return a
+ * fixed key in this case.
*/
- path_max = pathconf(name, _PC_PATH_MAX);
- if (path_max <= 0 || path_max >= 4096)
- path_max = 4096;
-#endif
- rpath = dss_malloc(path_max);
- rpath_limit = rpath + path_max;
-
- if (name[0] != '/') {
- if (!getcwd(rpath, path_max)) {
- ret = -ERRNO_TO_DSS_ERROR(errno);
- goto error;
- }
- dest = memchr(rpath, '\0', path_max);
- } else {
- rpath[0] = '/';
- dest = rpath + 1;
- }
-
- for (start = end = name; *start; start = end) {
- struct stat st;
- int n;
-
- /* Skip sequence of multiple path-separators. */
- while (*start == '/')
- ++start;
-
- /* Find end of path component. */
- for (end = start; *end && *end != '/'; ++end)
- /* Nothing. */ ;
-
- if (end - start == 0)
- break;
- else if (end - start == 1 && start[0] == '.')
- /* nothing */ ;
- else if (end - start == 2 && start[0] == '.' && start[1] == '.') {
- /* Back up to previous component, ignore if at root already. */
- if (dest > rpath + 1)
- while ((--dest)[-1] != '/') ;
- } else {
- size_t new_size;
-
- if (dest[-1] != '/')
- *dest++ = '/';
-
- if (dest + (end - start) >= rpath_limit) {
- ptrdiff_t dest_offset = dest - rpath;
-
- new_size = rpath_limit - rpath;
- if (end - start + 1 > path_max)
- new_size += end - start + 1;
- else
- new_size += path_max;
- rpath = dss_realloc(rpath, new_size);
- rpath_limit = rpath + new_size;
- dest = rpath + dest_offset;
- }
-
- memcpy(dest, start, end - start);
- dest += end - start;
- *dest = '\0';
-
- if (stat(rpath, &st) < 0) {
- ret = -ERRNO_TO_DSS_ERROR(errno);
- goto error;
- }
-
- if (S_ISLNK(st.st_mode)) {
- char *buf = alloca(path_max);
- size_t len;
-
- if (++num_links > MAXSYMLINKS) {
- ret = -ERRNO_TO_DSS_ERROR(ELOOP);
- goto error;
- }
-
- n = readlink(rpath, buf, path_max - 1);
- if (n < 0) {
- ret = -ERRNO_TO_DSS_ERROR(errno);
- goto error;
- }
- buf[n] = '\0';
-
- if (!extra_buf)
- extra_buf = alloca(path_max);
-
- len = strlen(end);
- if ((long int) (n + len) >= path_max) {
- ret = -ERRNO_TO_DSS_ERROR(ENAMETOOLONG);
- goto error;
- }
-
- /* Careful here, end may be a pointer into extra_buf... */
- memmove(&extra_buf[n], end, len + 1);
- name = end = memcpy(extra_buf, buf, n);
-
- if (buf[0] == '/') /* It's an absolute symlink */
- dest = rpath + 1;
- else /* Back up to previous component, ignore if at root already: */
- if (dest > rpath + 1)
- while ((--dest)[-1] != '/')
- ; /* nothing */
- } else if (!S_ISDIR(st.st_mode) && *end != '\0') {
- ret = -ERRNO_TO_DSS_ERROR(ENOTDIR);
- goto error;
- }
- }
- }
- if (dest > rpath + 1 && dest[-1] == '/')
- --dest;
- *dest = '\0';
- *resolved_path = rpath;
- return 1;
-error:
- free(rpath);
- *resolved_path = NULL;
- return ret;
-}
-
-static inline int get_key_or_die(char *config_file)
-{
- int ret;
- struct stat statbuf;
- char *rpath;
-
- assert(config_file);
- if (stat(config_file, &statbuf) == 0) {
- ret = dss_realpath(config_file, &rpath);
- if (ret < 0) {
- DSS_EMERG_LOG("could not resolve path %s: %s\n", config_file,
- dss_strerror(-ret));
- exit(EXIT_FAILURE);
- }
- DSS_DEBUG_LOG("resolved path: %s\n", rpath);
- } else
- /*
- * This happens if the user did not specify a config file, and
- * the default config file does not exist. Another (unlikely)
- * possibility is that the config file was removed between
- * startup and this call. We don't care about these corner
- * cases too much and just use the unresolved path in this
- * case.
- */
- rpath = dss_strdup(config_file);
- ret = super_fast_hash((uint8_t *)rpath, strlen(rpath), 0) >> 1;
- free(rpath);
- return ret;
+ return 0x0D55; /* no magic, this number just looks a bit like DSS */
}
-static int mutex_get(int key, int flags)
+static int mutex_get(key_t key, int flags)
{
int ret;
- DSS_DEBUG_LOG("getting semaphore 0x%x\n", key);
+ DSS_DEBUG_LOG(("getting semaphore 0x%lx\n", (long)key));
ret = semget(key, 2, flags);
if (ret < 0)
return -ERRNO_TO_DSS_ERROR(errno);
{
int ret;
- DSS_DEBUG_LOG("calling semop\n");
+ DSS_DEBUG_LOG(("calling semop\n"));
do {
ret = semop(id, sops, num);
if (ret >= 0)
static int mutex_lock(int id)
{
struct sembuf sops[4];
- int ret;
- DSS_DEBUG_LOG("locking\n");
+ DSS_DEBUG_LOG(("locking\n"));
sops[0].sem_num = 0;
sops[0].sem_op = 0;
sops[3].sem_op = 1;
sops[3].sem_flg = SEM_UNDO | IPC_NOWAIT;
- ret = do_semop(id, sops, 4);
- if (ret < 0)
- return -ERRNO_TO_DSS_ERROR(errno);
- return 1;
+ return do_semop(id, sops, 4);
}
-static int mutex_try_lock(int id)
+static bool mutex_is_locked(int id)
{
- struct sembuf sops[2];
+ struct sembuf sops;
int ret;
- DSS_DEBUG_LOG("trying to lock\n");
-
- sops[0].sem_num = 0;
- sops[0].sem_op = 0;
- sops[0].sem_flg = SEM_UNDO | IPC_NOWAIT;
+ DSS_DEBUG_LOG(("trying to lock\n"));
- sops[1].sem_num = 0;
- sops[1].sem_op = 1;
- sops[1].sem_flg = SEM_UNDO | IPC_NOWAIT;
+ sops.sem_num = 0;
+ sops.sem_op = 0;
+ sops.sem_flg = SEM_UNDO | IPC_NOWAIT;
- ret = do_semop(id, sops, 2);
+ ret = do_semop(id, &sops, 1);
if (ret < 0)
- return -ERRNO_TO_DSS_ERROR(errno);
- return 1;
+ return true;
+ return false;
}
int lock_dss(char *config_file)
{
- int ret, key = get_key_or_die(config_file);
+ int ret;
+ key_t key = get_key(config_file);
ret = mutex_get(key, IPC_CREAT | 0600);
if (ret < 0)
int get_dss_pid(char *config_file, pid_t *pid)
{
- int ret, semid, key = get_key_or_die(config_file);
+ int ret, semid;
+ key_t key = get_key(config_file);
+ if (pid)
+ *pid = 0;
ret = mutex_get(key, 0);
if (ret < 0)
return ret;
ret = semctl(semid, 1, GETPID);
if (ret < 0)
return -E_NOT_RUNNING;
- *pid = ret;
- ret = mutex_try_lock(semid);
- if (ret >= 0)
- return -E_NOT_RUNNING;
- return 1;
+ if (pid)
+ *pid = ret;
+ return mutex_is_locked(semid)? 1 : -E_NOT_RUNNING;
}
projects / dss.git / blobdiff