NAME
getmntent, setmntent, addmntent, endmntent, hasmntopt, getmntentr - get file system descriptor file entry SYNOPSIS
#include
#include
FILE *setmntent(const char *filename, const char *type); struct mntent *getmntent(FILE *fp); int addmntent(FILE *fp, const struct mntent *mnt); int endmntent(FILE *fp); char *hasmntopt(const struct mntent *mnt, const char *opt); /* GNU extension */ #include
struct mntent *getmntentr(FILE *fp, struct mntent *mntbuf, char *buf, int buflen); Feature Test Macro Requirements for glibc (see featuretestmacros(7)): getmntentr(): BSDSOURCE || SVIDSOURCE DESCRIPTION These routines are used to access the file system description file /etc/fstab and the mounted file system description file /etc/mtab. The setmntent() function opens the file system description file file‐ name and returns a file pointer which can be used by getmntent(). The argument type is the type of access required and can take the same val‐ ues as the mode argument of fopen(3). The getmntent() function reads the next line from the file system description file fp and returns a pointer to a structure containing the broken out fields from a line in the file. The pointer points to a static area of memory which is overwritten by subsequent calls to getm‐ ntent(). The addmntent() function adds the mntent structure mnt to the end of the open file fp. The endmntent() function closes the file system description file fp. The hasmntopt() function scans the mntopts field (see below) of the mntent structure mnt for a substring that matches opt. See and mount(8) for valid mount options. The reentrant getmntentr() function is similar to getmntent(), but stores the struct mount in the provided *mntbuf and stores the strings pointed to by the entries in that struct in the provided array buf of size buflen. The mntent structure is defined in as follows: struct mntent { char *mntfsname; /* name of mounted file system */ char *mntdir; /* file system path prefix */ char *mnttype; /* mount type (see mntent.h) */ char *mntopts; /* mount options (see mntent.h) */ int mntfreq; /* dump frequency in days */ int mntpassno; /* pass number on parallel fsck */ }; Since fields in the mtab and fstab files are separated by whitespace, octal escapes are used to represent the four characters space (\040), tab (\011), newline (\012) and backslash (\134) in those files when they occur in one of the four strings in a mntent structure. The rou‐ tines addmntent() and getmntent() will convert from string representa‐ tion to escaped representation and back. RETURN VALUE The getmntent() and getmntentr() functions return a pointer to the mntent structure or NULL on failure. The addmntent() function returns 0 on success and 1 on failure. The endmntent() function always returns 1. The hasmntopt() function returns the address of the substring if a match is found and NULL otherwise. FILES /etc/fstab file system description file /etc/mtab mounted file system description file CONFORMING TO The nonreentrant functions are from SunOS 4.1.3. A routine getmn‐ tentr() was introduced in HP-UX 10, but it returns an int. The proto‐
type shown above is glibc-only. NOTES System V also has a getmntent() function but the calling sequence dif‐ fers, and the returned structure is different. Under System V /etc/mnttab is used. 4.4BSD and Digital UNIX have a routine getm‐ ntinfo(), a wrapper around the system call getfsstat(). SEE ALSO fopen(3), fstab(5), mount(8) COLOPHON
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2009-09-15 GETMNTENT(3)