diff options
Diffstat (limited to 'lib/readutmp.h')
| -rw-r--r-- | lib/readutmp.h | 338 |
1 files changed, 338 insertions, 0 deletions
diff --git a/lib/readutmp.h b/lib/readutmp.h new file mode 100644 index 00000000000..dcfd44dbbc9 --- /dev/null +++ b/lib/readutmp.h @@ -0,0 +1,338 @@ +/* Declarations for GNU's read utmp module. + + Copyright (C) 1992-2007, 2009-2024 Free Software Foundation, Inc. + + This program is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see <https://www.gnu.org/licenses/>. */ + +/* Written by jla; revised by djm */ + +#ifndef __READUTMP_H__ +#define __READUTMP_H__ + +/* This file uses _GL_ATTRIBUTE_MALLOC, _GL_ATTRIBUTE_RETURNS_NONNULL, + HAVE_UTMP_H, HAVE_UTMPX_H, HAVE_STRUCT_UTMP_*, HAVE_STRUCT_UTMPX_*, + HAVE_UTMPNAME, HAVE_UTMPXNAME. */ +#if !_GL_CONFIG_H_INCLUDED +# error "Please include config.h first." +#endif + +#include "idx.h" + +#include <stdlib.h> +#include <sys/types.h> +#include <time.h> + +/* AIX 4.3.3 has both utmp.h and utmpx.h, but only struct utmp + has the ut_exit member. */ +#if (HAVE_UTMPX_H && HAVE_UTMP_H && HAVE_STRUCT_UTMP_UT_EXIT \ + && ! HAVE_STRUCT_UTMPX_UT_EXIT) +# undef HAVE_UTMPX_H +#endif + +/* HPUX 10.20 needs utmp.h, for the definition of e.g., UTMP_FILE. */ +#if HAVE_UTMP_H +# include <utmp.h> +#endif + +/* Needed for BOOT_TIME and USER_PROCESS. */ +#if HAVE_UTMPX_H +# if defined _THREAD_SAFE && defined UTMP_DATA_INIT + /* When including both utmp.h and utmpx.h on AIX 4.3, with _THREAD_SAFE + defined, work around the duplicate struct utmp_data declaration. */ +# define utmp_data gl_aix_4_3_workaround_utmp_data +# endif +# include <utmpx.h> +#endif + + +#ifdef __cplusplus +extern "C" { +#endif + + +/* Type of entries returned by read_utmp on all platforms. */ +struct gl_utmp +{ + /* All 'char *' here are of arbitrary length and point to storage + with lifetime equal to that of this struct. */ + char *ut_user; /* User name */ + char *ut_id; /* Session ID */ + char *ut_line; /* seat / device */ + char *ut_host; /* for remote sessions: user@host or host, + for local sessions: the X11 display :N */ + struct timespec ut_ts; /* time */ + pid_t ut_pid; /* process ID of ? */ + pid_t ut_session; /* process ID of session leader */ + short ut_type; /* BOOT_TIME, USER_PROCESS, or other */ + struct { int e_termination; int e_exit; } ut_exit; +}; + +/* The following types, macros, and constants describe the 'struct gl_utmp'. */ +#define UT_USER(UT) ((UT)->ut_user) +#define UT_TIME_MEMBER(UT) ((UT)->ut_ts.tv_sec) +#define UT_PID(UT) ((UT)->ut_pid) +#define UT_TYPE_EQ(UT, V) ((UT)->ut_type == (V)) +#define UT_TYPE_NOT_DEFINED 0 +#define UT_EXIT_E_TERMINATION(UT) ((UT)->ut_exit.e_termination) +#define UT_EXIT_E_EXIT(UT) ((UT)->ut_exit.e_exit) + +/* Type of entry returned by read_utmp(). */ +typedef struct gl_utmp STRUCT_UTMP; + +/* Size of the UT_USER (ut) member, or -1 if unbounded. */ +enum { UT_USER_SIZE = -1 }; + +/* Size of the ut->ut_id member, or -1 if unbounded. */ +enum { UT_ID_SIZE = -1 }; + +/* Size of the ut->ut_line member, or -1 if unbounded. */ +enum { UT_LINE_SIZE = -1 }; + +/* Size of the ut->ut_host member, or -1 if unbounded. */ +enum { UT_HOST_SIZE = -1 }; + + +/* When read_utmp accesses a file (as opposed to fetching the information + from systemd), it uses the following low-level types and macros. + Keep them here, rather than moving them into readutmp.c, for backward + compatibility. */ + +#if HAVE_UTMPX_H + +/* <utmpx.h> defines 'struct utmpx' with the following fields: + + Field Type Platforms + ---------- ------ --------- + ⎡ ut_user char[] glibc, musl, macOS, FreeBSD, AIX, HP-UX, IRIX, Solaris, Cygwin, Android + ⎣ ut_name char[] NetBSD, Minix + ut_id char[] glibc, musl, macOS, FreeBSD, NetBSD, Minix, AIX, HP-UX, IRIX, Solaris, Cygwin, Android + ut_line char[] glibc, musl, macOS, FreeBSD, NetBSD, Minix, AIX, HP-UX, IRIX, Solaris, Cygwin, Android + ut_pid pid_t glibc, musl, macOS, FreeBSD, NetBSD, Minix, AIX, HP-UX, IRIX, Solaris, Cygwin, Android + ut_type short glibc, musl, macOS, FreeBSD, NetBSD, Minix, AIX, HP-UX, IRIX, Solaris, Cygwin, Android + ⎡ ut_tv struct glibc, musl, macOS, FreeBSD, NetBSD, Minix, AIX, HP-UX, IRIX, Solaris, Cygwin, Android + ⎢ { tv_sec; tv_usec; } + ⎣ ut_time time_t Cygwin + ut_host char[] glibc, musl, macOS, FreeBSD, NetBSD, Minix, AIX, HP-UX, IRIX, Solaris, Cygwin, Android + ut_exit struct glibc, musl, NetBSD, Minix, HP-UX, IRIX, Solaris, Android + { e_termination; e_exit; } + ut_session [long] int glibc, musl, NetBSD, Minix, IRIX, Solaris, Android + ⎡ ut_addr [long] int HP-UX, Cygwin + ⎢ ut_addr_v6 [u]int[4] glibc, musl, Android + ⎣ ut_ss struct sockaddr_storage NetBSD, Minix + */ + +# if __GLIBC__ && _TIME_BITS == 64 +/* This is a near-copy of glibc's struct utmpx, which stops working + after the year 2038. Unlike the glibc version, struct utmpx32 + describes the file format even if time_t is 64 bits. */ +#define _GL_UT_USER_SIZE sizeof (((struct utmpx *) 0)->ut_user) +#define _GL_UT_ID_SIZE sizeof (((struct utmpx *) 0)->ut_id) +#define _GL_UT_LINE_SIZE sizeof (((struct utmpx *) 0)->ut_line) +#define _GL_UT_HOST_SIZE sizeof (((struct utmpx *) 0)->ut_host) +struct utmpx32 +{ + short int ut_type; /* Type of login. */ + pid_t ut_pid; /* Process ID of login process. */ + char ut_line[_GL_UT_LINE_SIZE]; /* Devicename. */ + char ut_id[_GL_UT_ID_SIZE]; /* Inittab ID. */ + char ut_user[_GL_UT_USER_SIZE]; /* Username. */ + char ut_host[_GL_UT_HOST_SIZE]; /* Hostname for remote login. */ + struct __exit_status ut_exit; /* Exit status of a process marked + as DEAD_PROCESS. */ + /* The fields ut_session and ut_tv must be the same size when compiled + 32- and 64-bit. This allows files and shared memory to be shared + between 32- and 64-bit applications. */ + int ut_session; /* Session ID, used for windowing. */ + struct + { + /* Seconds. Unsigned not signed, as glibc did not exist before 1970, + and if the format is still in use after 2038 its timestamps + will surely have the sign bit on. This hack stops working + at 2106-02-07 06:28:16 UTC. */ + unsigned int tv_sec; + int tv_usec; /* Microseconds. */ + } ut_tv; /* Time entry was made. */ + int ut_addr_v6[4]; /* Internet address of remote host. */ + char ut_reserved[20]; /* Reserved for future use. */ +}; +# define UTMP_STRUCT_NAME utmpx32 +# else +# define UTMP_STRUCT_NAME utmpx +# endif +# define SET_UTMP_ENT setutxent +# define GET_UTMP_ENT getutxent +# define END_UTMP_ENT endutxent +# ifdef HAVE_UTMPXNAME /* glibc, musl, macOS, NetBSD, Minix, IRIX, Solaris, Cygwin */ +# define UTMP_NAME_FUNCTION utmpxname +# elif defined UTXDB_ACTIVE /* FreeBSD */ +# define UTMP_NAME_FUNCTION(x) setutxdb (UTXDB_ACTIVE, x) +# elif defined __ANDROID__ /* Android */ +/* As of Android NDK r26, the getutxent, setutxent functions are no-ops. + Therefore we can ignore the file name. */ +# define UTMP_NAME_FUNCTION(x) ((void) (x)) +# endif + +#elif HAVE_UTMP_H + +/* <utmp.h> defines 'struct utmp' with the following fields: + + Field Type Platforms + ---------- ------ --------- + ⎡ ut_user char[] glibc, musl, AIX, HP-UX, IRIX, Solaris, Cygwin, Android + ⎣ ut_name char[] macOS, old FreeBSD, NetBSD, OpenBSD, Minix + ut_id char[] glibc, musl, AIX, HP-UX, IRIX, Solaris, Cygwin, Android + ut_line char[] glibc, musl, macOS, old FreeBSD, NetBSD, OpenBSD, Minix, AIX, HP-UX, IRIX, Solaris, Cygwin, Android + ut_pid pid_t glibc, musl, AIX, HP-UX, IRIX, Solaris, Cygwin, Android + ut_type short glibc, musl, AIX, HP-UX, IRIX, Solaris, Cygwin, Android + ⎡ ut_tv struct glibc, musl, Android + ⎢ { tv_sec; tv_usec; } + ⎣ ut_time time_t macOS, old FreeBSD, NetBSD, OpenBSD, Minix, AIX, HP-UX, IRIX, Solaris, Cygwin + ut_host char[] glibc, musl, macOS, old FreeBSD, NetBSD, OpenBSD, Minix, AIX, HP-UX, Cygwin, Android + ut_exit struct glibc, musl, AIX, HP-UX, IRIX, Solaris, Android + { e_termination; e_exit; } + ut_session [long] int glibc, musl, Android + ⎡ ut_addr [long] int HP-UX, Cygwin + ⎣ ut_addr_v6 [u]int[4] glibc, musl, Android + */ + +# define UTMP_STRUCT_NAME utmp +# define SET_UTMP_ENT setutent +# define GET_UTMP_ENT getutent +# define END_UTMP_ENT endutent +# ifdef HAVE_UTMPNAME /* glibc, musl, NetBSD, Minix, AIX, HP-UX, IRIX, Solaris, Cygwin, Android */ +# define UTMP_NAME_FUNCTION utmpname +# endif + +#endif + +/* Evaluates to 1 if gl_utmp's ut_id field may ever have a non-zero value. */ +#define HAVE_STRUCT_XTMP_UT_ID \ + (READUTMP_USE_SYSTEMD \ + || (HAVE_UTMPX_H ? HAVE_STRUCT_UTMPX_UT_ID : HAVE_STRUCT_UTMP_UT_ID)) + +/* Evaluates to 1 if gl_utmp's ut_pid field may ever have a non-zero value. */ +#define HAVE_STRUCT_XTMP_UT_PID \ + (READUTMP_USE_SYSTEMD \ + || (HAVE_UTMPX_H ? HAVE_STRUCT_UTMPX_UT_PID : HAVE_STRUCT_UTMP_UT_PID)) + +/* Evaluates to 1 if gl_utmp's ut_host field may ever be non-empty. */ +#define HAVE_STRUCT_XTMP_UT_HOST \ + (READUTMP_USE_SYSTEMD \ + || (HAVE_UTMPX_H ? HAVE_STRUCT_UTMPX_UT_HOST : HAVE_STRUCT_UTMP_UT_HOST)) + +/* Definition of UTMP_FILE. + On glibc systems, UTMP_FILE is "/var/run/utmp". */ +#if !defined UTMP_FILE && defined _PATH_UTMP +# define UTMP_FILE _PATH_UTMP +#endif +#ifdef UTMPX_FILE /* Solaris, SysVr4 */ +# undef UTMP_FILE +# define UTMP_FILE UTMPX_FILE +#endif +#ifndef UTMP_FILE +# define UTMP_FILE "/etc/utmp" +#endif + +/* Definition of WTMP_FILE. + On glibc systems, UTMP_FILE is "/var/log/wtmp". */ +#if !defined WTMP_FILE && defined _PATH_WTMP +# define WTMP_FILE _PATH_WTMP +#endif +#ifdef WTMPX_FILE /* Solaris, SysVr4 */ +# undef WTMP_FILE +# define WTMP_FILE WTMPX_FILE +#endif +#ifndef WTMP_FILE +# define WTMP_FILE "/etc/wtmp" +#endif + +/* In early versions of Android, <utmp.h> did not define BOOT_TIME, only + USER_PROCESS. We need to use the value that is defined in newer versions + of Android. */ +#if defined __ANDROID__ && !defined BOOT_TIME +# define BOOT_TIME 2 +#endif + +/* Some platforms, such as OpenBSD, don't have an ut_type field and don't have + the BOOT_TIME and USER_PROCESS macros. But we want to support them in + 'struct gl_utmp'. */ +#if !(HAVE_UTMPX_H ? HAVE_STRUCT_UTMPX_UT_TYPE : HAVE_STRUCT_UTMP_UT_TYPE) +# define BOOT_TIME 2 +# define USER_PROCESS 0 +#endif + +/* Macros that test (UT)->ut_type. */ +#ifdef BOOT_TIME +# define UT_TYPE_BOOT_TIME(UT) ((UT)->ut_type == BOOT_TIME) +#else +# define UT_TYPE_BOOT_TIME(UT) 0 +#endif +#ifdef USER_PROCESS +# define UT_TYPE_USER_PROCESS(UT) ((UT)->ut_type == USER_PROCESS) +#else +# define UT_TYPE_USER_PROCESS(UT) 0 +#endif + +/* Determines whether an entry *UT corresponds to a user process. */ +#define IS_USER_PROCESS(UT) \ + ((UT)->ut_user[0] && UT_TYPE_USER_PROCESS (UT)) + +/* Define if read_utmp is not just a dummy. */ +#if READUTMP_USE_SYSTEMD || HAVE_UTMPX_H || HAVE_UTMP_H || defined __CYGWIN__ || defined _WIN32 +# define READ_UTMP_SUPPORTED 1 +#endif + +/* Options for read_utmp. */ +enum + { + READ_UTMP_CHECK_PIDS = 1, + READ_UTMP_USER_PROCESS = 2, + READ_UTMP_BOOT_TIME = 4, + READ_UTMP_NO_BOOT_TIME = 8 + }; + +/* Return a copy of (UT)->ut_user, without trailing spaces, + as a freshly allocated string. */ +char *extract_trimmed_name (const STRUCT_UTMP *ut) + _GL_ATTRIBUTE_MALLOC _GL_ATTRIBUTE_DEALLOC_FREE + _GL_ATTRIBUTE_RETURNS_NONNULL; + +/* Read the utmp entries corresponding to file FILE into freshly- + malloc'd storage, set *UTMP_BUF to that pointer, set *N_ENTRIES to + the number of entries, and return zero. If there is any error, + return -1, setting errno, and don't modify the parameters. + A good candidate for FILE is UTMP_FILE. + If OPTIONS & READ_UTMP_CHECK_PIDS is nonzero, omit entries whose + process-IDs do not currently exist. + If OPTIONS & READ_UTMP_USER_PROCESS is nonzero, omit entries which + do not correspond to a user process. + If OPTIONS & READ_UTMP_BOOT_TIME is nonzero, omit all entries except + the one that contains the boot time. + If OPTIONS & READ_UTMP_NO_BOOT_TIME is nonzero, omit the boot time + entries. + + This function is not multithread-safe, since on many platforms it + invokes the functions setutxent, getutxent, endutxent. These + functions are needed because they may lock FILE (so that we don't + read garbage when a concurrent process writes to FILE), but their + drawback is that they have a common global state. */ +int read_utmp (char const *file, idx_t *n_entries, STRUCT_UTMP **utmp_buf, + int options); + + +#ifdef __cplusplus +} +#endif + +#endif /* __READUTMP_H__ */ |