shadow(3) Library Calls shadow(3) shadow, getspnam - #include struct spwd *getspent(); struct spwd *getspnam(char *name); void setspent(); void endspent(); struct spwd *fgetspent(FILE *fp); struct spwd *sgetspent(char *cp); int putspent(struct spwd *p, FILE *fp); int lckpwdf(); int ulckpwdf(); shadow manipulates the contents of the shadow password file, /etc/shadow. The structure in the #include file is: struct spwd { char *sp_namp; /* ' */ char *sp_pwdp; /* */ long int sp_lstchg; /* */ long int sp_min; /* , . */ long int sp_max; /* */ long int sp_warn; /* */ long int sp_inact; /* */ long int sp_expire; /* , */ unsigned long int sp_flag; /* */ } : o sp_namp - ' - o sp_pwdp - - o sp_lstchg - 1 1970 , o sp_min - , o sp_max - , o sp_warn - , , o sp_inact - o sp_expire - 1 1970 , o sp_flag - getspent, getspname, fgetspent, and sgetspent each return a pointer to a struct spwd. getspent returns the next entry from the file, and fgetspent returns the next entry from the given stream, which is assumed to be a file of the proper format. sgetspent returns a pointer to a struct spwd using the provided string as input. getspnam searches from the current position in the file for an entry matching name. setspent and endspent may be used to begin and end, respectively, access to the shadow password file. The lckpwdf and ulckpwdf routines should be used to insure exclusive access to the /etc/shadow file. lckpwdf attempts to acquire a lock using pw_lock for up to 15 seconds. It continues by attempting to acquire a second lock using spw_lock for the remainder of the initial 15 seconds. Should either attempt fail after a total of 15 seconds, lckpwdf returns -1. When both locks are acquired 0 is returned. Routines return NULL if no more entries are available or if an error occurs during processing. Routines which have int as the return value return 0 for success and -1 for failure. , . /etc/shadow . . getpwent(3), shadow(5). shadow-utils 4.16.0 02/07/2024 shadow(3)