Content-type: text/html Man page of getpwent

getpwent

Section: C Library Functions (3)
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NAME

endpwent, fgetpwent, getpwent, getpwnam, getpwuid, putpwent, setpwent, setpwfile, endpwent_r, fgetpwent_r, getpwent_r, getpwnam_r, getpwuid_r, setpwent_r - Access user attribute information in the user database  

LIBRARY

Standard C Library (libc.so, libc.a)  

SYNOPSIS

#include <pwd.h>

void endpwent(void);

struct passwd *fgetpwent (FILE *f);

struct passwd *getpwent(void);

struct passwd *getpwnam(
        const char *name);

struct passwd *getpwuid(
        uid_t uid);

int putpwent(
        struct passwd *passwd,
        FILE *file);

void setpwent(void);

void setpwfile(
        const char *filename);

void endpwent_r(FILE **pw_fp);

int fgetpwent_r(
        FILE *f,
        struct passwd *pwd,
        char *buffer,
        int len);

int getpwent_r(
        struct passwd *pwd,
        char *buffer,
        int len,
        FILE **pw_fp);

int getpwnam_r(
        const char *name,
        struct passwd *pwd,
        char *buffer,
        size_t len,
        struct passwd **result);

int getpwuid_r(
        uid_t uid,
        struct passwd *pwd,
        char *buffer,
        size_t len,
        struct passwd **result);

int setpwent_r(FILE **pw_fp);

[Digital]  The following functions are supported in order to maintain backward compatibility with previous versions of the operating system. You should not use them in new designs. int setpwent(void);

int getpwnam_r(
        const char *name,
        struct passwd *result,
        char *buffer,
        int len);

int getpwuid_r(
        uid_t uid,
        struct passwd *result,
        char *buffer,
        int len);  

STANDARDS

Interfaces documented on this reference page conform to industry standards as follows:

getpwnam_r(), getpwuid_r():  POSIX.1c

getpwnam(), getpwuid():  XPG4, XPG4-UNIX

endpwent(), getpwent(), setpwent():  XPG4-UNIX

Refer to the standards(5) reference page for more information about industry standards and associated tags.  

PARAMETERS

Specifies the ID of the user for which the attributes are to be read. Specifies the name of the user for which the attributes are to be read. Specifies the location where the retrieved passwd structure is to be placed. Specifies the password structure that contains the user attributes that are to be written. Specifies a stream open for writing to a file. Upon successful return, points to the retrieved passwd structure. Upon unsuccessful return, the result is set to NULL. A working buffer for the result parameter that is able to hold the largest password entry in /etc/passwd.

[Digital]  The minimum buffer size is 1024 bytes as defined for SIABUFSIZ in /usr/include/sia.h. Specifies the length of the character array that buffer points to.
[Digital]  The minimum buffer size is 1024 bytes as defined for SIABUFSIZ in /usr/include/sia.h. Specifies a file that contains the next passwd structure. (This is for the fgetpwent() and fgetpwent_r() functions.) Points to a file stream open for reading password entries. Specifies a new default password file rather than using the default /etc/passwd file.
 

DESCRIPTION

The endpwent(), fgetpwent(), getpwent(), getpwnam(), getpwuid(), putpwent(), and setpwent() functions may be used to access the basic user attributes.

The getpwent(), getpwnam(), and getpwuid() functions return information about the specified user. The getpwent() function returns the next user entry in a sequential search that may use a private file pointer. The getpwnam() function returns the first user entry in the database with a pw_name field that matches the name parameter. The getpwuid() function returns the first user entry in the database with a pw_uid field that matches the uid parameter.

The putpwent() function writes a password entry into a file in the colon-separated format of the /etc/passwd file.

The setpwent() function ensures that the next call to getpwent() returns the first entry.

The endpwent() function closes the user database and any private stream used by getpwent(). When the /etc/passwd file is updated, it may be necessary to call endpwent() to ensure that subsequent getpwent() calls will return the new data.

The user structure, which is returned by the getpwent(), getpwnam(), and getpwuid() functions and which is written by the putpwent() function, is defined in the pwd.h file and has the following members: The name of the user. The encrypted password of the user. If the password is not stored in the /etc/passwd file and the invoker does not have access to the shadow file that contains them, this field will contain an unencryptable string. The ID of the user. The group ID of the principle group of the user. The personal information about the user. The home directory of the user. The initial program for the user.

The endpwent_r(), fgetpwent_r() getpwent_r(), getpwnam_r(), getpwuid_r(), and setpwent_r() functions are the reentrant versions of the endpwent(), fgetpwent() getpwent(), getpwnam(), getpwuid(), and setpwent() functions, respectively.

The endpwent_r(), getpwent_r(), and setpwent_r() functions use the pw_fp parameter to keep track of the calls to the getpwent_r() function, so that subsequent calls will return subsequent password entries from the /etc/passwd file. The setpwent_r() function must be called with the address of a valid file pointer (which may be NULL). Upon successful completion, the result is stored in result.

The fgetpwent() and fgetpwent_r() functions get a password file entry from the file specified by the f parameter, rather than from the /etc/passwd file. This file must have the format of the /etc/passwd file.

The setpwfile() function sets the new default password file to be filename instead of /etc/passwd.

[Digital]  The system searches using NIS if NIS is available and your /etc/passwd file has NIS type entries (that is, +:, +name, [email protected], and [email protected]). The fgetpw* routines do not use NIS. The operating system provides the getpwent_local, getpwuid_local, and getpwnam_local routines to avoid NIS. The getpw*_local routines are provided only on Digital systems and are not in the pwd.h header file.  

NOTES

All information generated by the fgetpwent(), getpwent(), getpwnam(), and getpwuid() functions is stored in a static area and will be overwritten on subsequent calls to these routines. These static areas may include private I/O streams or network resources.

Password file entries that are too long are ignored.

Note that the pw_fp parameter must be initialized by the user to NULL before the setpwent_r() function is called for the first time.  

RETURN VALUES

Upon successful completion, the fgetpwent(), getpwent(), getpwnam(), and getpwuid() functions return a pointer to a valid password structure. Otherwise, NULL is returned.

[POSIX]  Upon successful completion, the getpwnam_r and getpwuid_r functions return a value of 0 (zero). Otherwise, they return an errno value.

Upon successful completion, the fgetpwent_r() and getpwent_r() functions (as well as the obsolete versions of the getpwnam_r() and getpwuid_r() functions, return a value of 0 (zero). Otherwise, they return a value of -1 and set errno to indicate the error.  

ERRORS

If any of the following conditions occurs, the getpwnam_r(), and getpwuid_r() functions set errno to the corresponding value: [POSIX]  The amount of storage specified by buffer and len is too small to contain the data to be referenced by the resulting struct passwd structure.  

RELATED INFORMATION

Functions: getgrent(3), sia_getpasswd(3)

Standards: standards(5)

Files: /etc/passwd, /etc/passwd.dir, /etc/passwd.pag delim off


 

Index

NAME
LIBRARY
SYNOPSIS
STANDARDS
PARAMETERS
DESCRIPTION
NOTES
RETURN VALUES
ERRORS
RELATED INFORMATION

This document was created by man2html, using the manual pages.
Time: 02:41:35 GMT, October 02, 2010