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- /* utent.c <ndf@linux.mit.edu> */
- /* Let it be known that this is very possibly the worst standard ever. HP-UX
- does one thing, someone else does another, linux another... If anyone
- actually has the standard, please send it to me.
- Note that because of the way this stupid stupid standard works, you
- have to call endutent() to close the file even if you've not called
- setutent -- getutid and family use the same file descriptor.
- Modified by Erik Andersen for uClibc...
- */
- #include <features.h>
- #include <stdio.h>
- #include <stdlib.h>
- #include <unistd.h>
- #include <fcntl.h>
- #include <paths.h>
- #include <errno.h>
- #include <string.h>
- #include <utmp.h>
- #ifdef __UCLIBC_HAS_THREADS__
- #include <pthread.h>
- static pthread_mutex_t utmplock = PTHREAD_MUTEX_INITIALIZER;
- # define LOCK pthread_mutex_lock(&utmplock)
- # define UNLOCK pthread_mutex_unlock(&utmplock);
- #else
- # define LOCK
- # define UNLOCK
- #endif
- /* Some global crap */
- static int static_fd = -1;
- static struct utmp static_utmp;
- static const char default_file_name[] = _PATH_UTMP;
- static const char *static_ut_name = (const char *) default_file_name;
- static struct utmp *__getutent(int utmp_fd)
- {
- if (utmp_fd == -1) {
- setutent();
- }
- if (utmp_fd == -1) {
- return NULL;
- }
- LOCK;
- if (read(utmp_fd, (char *) &static_utmp, sizeof(struct utmp)) != sizeof(struct utmp))
- {
- return NULL;
- }
- UNLOCK;
- return &static_utmp;
- }
- void setutent(void)
- {
- int ret;
- LOCK;
- if (static_fd == -1) {
- if ((static_fd = open(static_ut_name, O_RDWR)) < 0) {
- if ((static_fd = open(static_ut_name, O_RDONLY)) < 0) {
- goto bummer;
- }
- }
- /* Make sure the file will be closed on exec() */
- ret = fcntl(static_fd, F_GETFD, 0);
- if (ret >= 0) {
- ret = fcntl(static_fd, F_GETFD, 0);
- }
- if (ret < 0) {
- bummer:
- UNLOCK;
- static_fd = -1;
- close(static_fd);
- return;
- }
- }
- lseek(static_fd, 0, SEEK_SET);
- UNLOCK;
- return;
- }
- void endutent(void)
- {
- LOCK;
- if (static_fd != -1) {
- close(static_fd);
- }
- static_fd = -1;
- UNLOCK;
- }
- /* Locking is done in __getutent */
- struct utmp *getutent(void)
- {
- return __getutent(static_fd);
- }
- /* Locking is done in __getutent */
- struct utmp *getutid (const struct utmp *utmp_entry)
- {
- struct utmp *lutmp;
- while ((lutmp = __getutent(static_fd)) != NULL) {
- if ( (utmp_entry->ut_type == RUN_LVL ||
- utmp_entry->ut_type == BOOT_TIME ||
- utmp_entry->ut_type == NEW_TIME ||
- utmp_entry->ut_type == OLD_TIME) &&
- lutmp->ut_type == utmp_entry->ut_type)
- {
- return lutmp;
- }
- if ( (utmp_entry->ut_type == INIT_PROCESS ||
- utmp_entry->ut_type == DEAD_PROCESS ||
- utmp_entry->ut_type == LOGIN_PROCESS ||
- utmp_entry->ut_type == USER_PROCESS) &&
- !strncmp(lutmp->ut_id, utmp_entry->ut_id, sizeof(lutmp->ut_id)))
- {
- return lutmp;
- }
- }
- return NULL;
- }
- /* Locking is done in __getutent */
- struct utmp *getutline(const struct utmp *utmp_entry)
- {
- struct utmp *lutmp;
- while ((lutmp = __getutent(static_fd)) != NULL) {
- if ((lutmp->ut_type == USER_PROCESS || lutmp->ut_type == LOGIN_PROCESS) &&
- !strcmp(lutmp->ut_line, utmp_entry->ut_line))
- {
- return lutmp;
- }
- }
- return NULL;
- }
- struct utmp *pututline (const struct utmp *utmp_entry)
- {
- LOCK;
- /* Ignore the return value. That way, if they've already positioned
- the file pointer where they want it, everything will work out. */
- lseek(static_fd, (off_t) - sizeof(struct utmp), SEEK_CUR);
- if (getutid(utmp_entry) != NULL) {
- lseek(static_fd, (off_t) - sizeof(struct utmp), SEEK_CUR);
- if (write(static_fd, utmp_entry, sizeof(struct utmp)) != sizeof(struct utmp))
- return NULL;
- } else {
- lseek(static_fd, (off_t) 0, SEEK_END);
- if (write(static_fd, utmp_entry, sizeof(struct utmp)) != sizeof(struct utmp))
- return NULL;
- }
- UNLOCK;
- return (struct utmp *)utmp_entry;
- }
- int utmpname (const char *new_ut_name)
- {
- LOCK;
- if (new_ut_name != NULL) {
- if (static_ut_name != default_file_name)
- free((char *)static_ut_name);
- static_ut_name = strdup(new_ut_name);
- if (static_ut_name == NULL) {
- /* We should probably whine about out-of-memory
- * errors here... Instead just reset to the default */
- static_ut_name = default_file_name;
- }
- }
- if (static_fd != -1)
- close(static_fd);
- UNLOCK;
- return 0;
- }
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