mntent.c

它通过提供glibc兼容使得应用程序移植到较小的c 库时相当得容易. 它能够应用到带虚拟存储的Linux和uClinux上.在大多数带MMU部件的平台上为使它更加紧凑,它也能够编译成共享库.uClib

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <mntent.h>

#ifdef __UCLIBC_HAS_THREADS__
#include <pthread.h>
static pthread_mutex_t mylock = PTHREAD_MUTEX_INITIALIZER;
# define LOCK	pthread_mutex_lock(&mylock)
# define UNLOCK	pthread_mutex_unlock(&mylock);
#else
# define LOCK
# define UNLOCK
#endif

/* Reentrant version of getmntent.  */
struct mntent *getmntent_r (FILE *filep, 
	struct mntent *mnt, char *buff, int bufsize)
{
	char *cp, *ptrptr;
	const char *sep = " \t\n";

	if (!filep || !mnt || !buff)
	    return NULL;

	/* Loop on the file, skipping comment lines. - FvK 03/07/93 */
	while ((cp = fgets(buff, bufsize, filep)) != NULL) {
		if (buff[0] == '#' || buff[0] == '\n')
			continue;
		break;
	}

	/* At the EOF, the buffer should be unchanged. We should
	 * check the return value from fgets ().
	 */
	if (cp == NULL)
		return NULL;

	ptrptr = 0;
	mnt->mnt_fsname = strtok_r(buff, sep, &ptrptr);
	if (mnt->mnt_fsname == NULL)
		return NULL;

	mnt->mnt_dir = strtok_r(NULL, sep, &ptrptr);
	if (mnt->mnt_dir == NULL)
		return NULL;

	mnt->mnt_type = strtok_r(NULL, sep, &ptrptr);
	if (mnt->mnt_type == NULL)
		return NULL;

	mnt->mnt_opts = strtok_r(NULL, sep, &ptrptr);
	if (mnt->mnt_opts == NULL)
		mnt->mnt_opts = "";

	cp = strtok_r(NULL, sep, &ptrptr);
	mnt->mnt_freq = (cp != NULL) ? atoi(cp) : 0;

	cp = strtok_r(NULL, sep, &ptrptr);
	mnt->mnt_passno = (cp != NULL) ? atoi(cp) : 0;

	return mnt;
}

struct mntent *getmntent(FILE * filep)
{
    struct mntent *tmp;
    static char buff[BUFSIZ];
    static struct mntent mnt;
    LOCK;
    tmp = getmntent_r(filep, &mnt, buff, sizeof buff);
    UNLOCK;
    return(tmp);
}

int addmntent(FILE * filep, const struct mntent *mnt)
{
	if (fseek(filep, 0, SEEK_END) < 0)
		return 1;

	if (fprintf (filep, "%s %s %s %s %d %d\n", mnt->mnt_fsname, mnt->mnt_dir,
		 mnt->mnt_type, mnt->mnt_opts, mnt->mnt_freq, mnt->mnt_passno) < 1)
		return 1;

	return 0;
}

char *hasmntopt(const struct mntent *mnt, const char *opt)
{
	return strstr(mnt->mnt_opts, opt);
}

FILE *setmntent(const char *name, const char *mode)
{
	return fopen(name, mode);
}

int endmntent(FILE * filep)
{
	if (filep != NULL)
		fclose(filep);
	return 1;
}