ttyname.c revision 7257d1b4d25bfac0c802847390e98a464fd787ac
/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright 2008 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
/* Copyright (c) 1988 AT&T */
/* All Rights Reserved */
#pragma ident "%Z%%M% %I% %E% SMI"
/*
* ttyname(f): return "/dev/X" (where X is a relative pathname
* under /dev/), which is the name of the tty character special
* file associated with the file descriptor f, or NULL if the
* pathname cannot be found.
*
* Ttyname tries to find the tty file by matching major/minor
* device, file system ID, and inode numbers of the file
* descriptor parameter to those of files in the /dev/ directory.
*
* It attempts to find a match on major/minor device numbers,
* file system ID, and inode numbers, but failing to match on
* all three, settles for just a match on device numbers and
* file system ID.
*
* To achieve higher performance and more flexible functionality,
* ttyname first looks for the tty file in the directories specified
* in the configuration file /etc/ttysrch. Entries in /etc/ttysrch
* may be qualified to specify that a partial match may be acceptable.
* This further improves performance by allowing an entry which
* matches major/minor and file system ID, but not inode number
* without searching the entire /dev tree. If /etc/ttysrch does not
* exist, ttyname looks in a default list of directories. If after
* looking in the most likely places, ttyname still cannot find the
* tty file, it recursively searches thru the rest of the /dev/
* directory.
*
* In addition to the public interfaces, ttyname() & ttyname_r(), which
* do the lookup based on an open file descriptor,
* the private interface _ttyname_dev() does the lookup based on a
* major/minor device. It follows the same order of lookup rules and
* returns similar information, but matches on just the major/minor
* device numbers.
*/
#pragma weak _ttyname = ttyname
#include "lint.h"
#include "mtlib.h"
#include "libc.h"
#include "_libc_gettext.h"
#include <sys/sysmacros.h>
#include <sys/types.h>
#include <dirent.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <stdlib.h>
#include <ctype.h>
#include <string.h>
#include <stdio.h>
#include <unistd.h>
#include <thread.h>
#include <synch.h>
#include <errno.h>
#include <limits.h>
#include <sys/mkdev.h>
#include "tsd.h"
typedef struct entry {
char *name;
int flags;
} entry_t;
typedef struct special {
const char *spcl_name; /* device name */
dev_t spcl_rdev; /* matching major/minor devnum */
dev_t spcl_fsdev; /* devnum of containing FS */
ino_t spcl_inum; /* inum of entry in FS */
} spcl_t;
static int srch_dir(const entry_t path, int match_mask, int depth,
const entry_t skip_dirs[], struct stat64 *fsb);
static const entry_t *get_pri_dirs(void);
static char *ispts(struct stat64 *fsb, int match_mask);
static char *ispty(struct stat64 *fsb, int match_mask);
static void itoa(int i, char *ptr);
static char *_ttyname_common(struct stat64 *fsp, char *buffer,
uint_t match_mask);
#define MAX_DEV_PATH TTYNAME_MAX
#define MAX_SRCH_DEPTH 4
#define MATCH_MM 1
#define MATCH_FS 2
#define MATCH_INO 4
#define MATCH_ALL 7
#define DEV "/dev"
#define TTYSRCH "/etc/ttysrch"
#define PTS "/dev/pts"
static const entry_t dev_dir =
{ "/dev", MATCH_ALL };
static const entry_t def_srch_dirs[] = { /* default search list */
{ "/dev/pts", MATCH_ALL },
{ "/dev/term", MATCH_ALL },
{ "/dev/zcons", MATCH_ALL },
{ NULL, 0 }
};
static char *dir_buf; /* directory buffer for ttysrch body */
static entry_t *dir_vec; /* directory vector for ttysrch ptrs */
static size_t dir_size; /* ttysrch file size */
static timestruc_t dir_mtim; /* ttysrch file modification time */
static char rbuf[MAX_DEV_PATH]; /* perfect match file name */
static char dev_rbuf[MAX_DEV_PATH]; /* partial match file name */
static int dev_flag; /* if set, dev + rdev match was found */
static spcl_t special_case[] = {
"/dev/tty", 0, 0, 0,
"/dev/console", 0, 0, 0,
"/dev/conslog", 0, 0, 0,
"/dev/systty", 0, 0, 0,
"/dev/wscons", 0, 0, 0
};
#define NUMSPECIAL (sizeof (special_case) / sizeof (spcl_t))
static spcl_t ptmspecial = {
"/dev/ptmx", 0, 0, 0
};
static dev_t ptcdev = NODEV;
static dev_t ptsldev = NODEV;
char *
_ttyname_dev(dev_t rdev, char *buffer, size_t buflen)
{
struct stat64 fsb;
fsb.st_rdev = rdev;
if (buflen < MAX_DEV_PATH) {
errno = ERANGE;
return (NULL);
}
return (_ttyname_common(&fsb, buffer, MATCH_MM));
}
/*
* POSIX.1c Draft-6 version of the function ttyname_r.
* It was implemented by Solaris 2.3.
*/
char *
ttyname_r(int f, char *buffer, int buflen)
{
struct stat64 fsb; /* what we are searching for */
/*
* do we need to search anything at all? (is fildes a char special tty
* file?)
*/
if (fstat64(f, &fsb) < 0) {
errno = EBADF;
return (0);
}
if ((isatty(f) == 0) ||
((fsb.st_mode & S_IFMT) != S_IFCHR)) {
errno = ENOTTY;
return (0);
}
if (buflen < MAX_DEV_PATH) {
errno = ERANGE;
return (0);
}
return (_ttyname_common(&fsb, buffer, MATCH_ALL));
}
static char *
_ttyname_common(struct stat64 *fsp, char *buffer, uint_t match_mask)
{
struct stat64 tfsb;
const entry_t *srch_dirs; /* priority directories */
spcl_t *spclp;
int i;
int found = 0;
int dirno = 0;
int is_pts = 0;
char *retval = NULL;
char *pt = NULL;
/*
* We can't use lmutex_lock() here because we call malloc()/free()
* and _libc_gettext(). Use the brute-force callout_lock_enter().
*/
callout_lock_enter();
/*
* match special cases
*/
for (spclp = special_case, i = 0; i < NUMSPECIAL; spclp++, i++) {
if ((spclp->spcl_inum | spclp->spcl_fsdev |
spclp->spcl_rdev) == 0) {
if (stat64(spclp->spcl_name, &tfsb) != 0)
continue;
spclp->spcl_rdev = tfsb.st_rdev;
spclp->spcl_fsdev = tfsb.st_dev;
spclp->spcl_inum = tfsb.st_ino;
}
if (match_mask == MATCH_MM) {
if (spclp->spcl_rdev == fsp->st_rdev) {
retval = strcpy(rbuf, spclp->spcl_name);
goto out;
}
} else if (spclp->spcl_fsdev == fsp->st_dev &&
spclp->spcl_rdev == fsp->st_rdev &&
spclp->spcl_inum == fsp->st_ino) {
retval = strcpy(rbuf, spclp->spcl_name);
goto out;
}
}
/*
* additional special case: ptm clone device
* ptm devs have no entries in /dev
* if major number matches, just short circuit any further lookup
* NOTE: the minor number of /dev/ptmx is the ptm major number
*/
spclp = &ptmspecial;
if ((spclp->spcl_inum | spclp->spcl_fsdev | spclp->spcl_rdev) == 0) {
if (stat64(spclp->spcl_name, &tfsb) == 0) {
spclp->spcl_rdev = tfsb.st_rdev;
spclp->spcl_fsdev = tfsb.st_dev;
spclp->spcl_inum = tfsb.st_ino;
}
}
if ((spclp->spcl_rdev != 0) &&
(minor(spclp->spcl_rdev) == major(fsp->st_rdev)))
goto out;
/*
* additional special case: pty dev
* one of the known default pairs of /dev/ptyXX or /dev/ttyXX
*/
if ((retval = ispty(fsp, match_mask)) != NULL)
goto out;
/*
* search the priority directories
*/
srch_dirs = get_pri_dirs();
dev_flag = 0;
while ((!found) && (srch_dirs[dirno].name != NULL)) {
/*
* if /dev is one of the priority directories, only
* search its top level(set depth = MAX_SEARCH_DEPTH)
*/
/*
* Is /dev/pts then just do a quick check. We don't have
* to stat the entire /dev/pts dir.
*/
if (strcmp(PTS, srch_dirs[dirno].name) == NULL) {
if ((pt = ispts(fsp, match_mask)) != NULL) {
is_pts = 1;
found = 1;
}
} else {
found = srch_dir(srch_dirs[dirno], match_mask,
((strcmp(srch_dirs[dirno].name, dev_dir.name)
== 0) ? MAX_SRCH_DEPTH : 1), 0, fsp);
}
dirno++;
}
/*
* search the /dev/ directory, skipping priority directories
*/
if (!found)
found = srch_dir(dev_dir, match_mask, 0, srch_dirs, fsp);
/*
* return
*/
if (found) {
if (is_pts)
retval = pt;
else
retval = rbuf;
} else if (dev_flag)
retval = dev_rbuf;
else
retval = NULL;
out: retval = (retval ? strcpy(buffer, retval) : NULL);
callout_lock_exit();
return (retval);
}
/*
* POSIX.1c standard version of the function ttyname_r.
* User gets it via static ttyname_r from the header file.
*/
int
__posix_ttyname_r(int fildes, char *name, size_t namesize)
{
int nerrno = 0;
int oerrno = errno;
int namelen;
errno = 0;
if (namesize > INT_MAX)
namelen = INT_MAX;
else
namelen = (int)namesize;
if (ttyname_r(fildes, name, namelen) == NULL) {
if (errno == 0)
nerrno = EINVAL;
else
nerrno = errno;
}
errno = oerrno;
return (nerrno);
}
/*
* Checks if the name is under /dev/pts directory
*/
static char *
ispts(struct stat64 *fsb, int match_mask)
{
static char buf[MAX_DEV_PATH];
struct stat64 stb;
(void) strcpy(buf, "/dev/pts/");
itoa(minor(fsb->st_rdev), buf+strlen(buf));
if (stat64(buf, &stb) != 0)
return (NULL);
if (match_mask == MATCH_MM) {
if (stb.st_rdev == fsb->st_rdev)
return (buf);
} else if (stb.st_rdev == fsb->st_rdev && stb.st_dev == fsb->st_dev &&
stb.st_ino == fsb->st_ino)
return (buf);
return (NULL);
}
/*
* Checks if the dev is a known pty master or slave device
*/
#define MAXDEFAULTPTY 48
static char *
ispty(struct stat64 *fsb, int match_mask)
{
static char buf[16]; /* big enough for "/dev/XtyXX" */
struct stat64 stb;
minor_t dmin;
char prefix;
if (ptsldev == NODEV && stat64("/dev/ttyp0", &stb) == 0)
ptsldev = stb.st_rdev;
/*
* check for a ptsl dev (/dev/ttyXX)
*/
prefix = 't';
if (major(fsb->st_rdev) != major(ptsldev)) {
/*
* not a ptsl, check for a ptc
*/
if (ptcdev == NODEV && stat64("/dev/ptyp0", &stb) == 0)
ptcdev = stb.st_rdev;
/*
* check for a ptc dev (/dev/ptyXX)
*/
prefix = 'p';
if (major(fsb->st_rdev) != major(ptcdev))
return (NULL);
}
/*
* check if minor number is in the known range
*/
dmin = minor(fsb->st_rdev);
if (dmin > MAXDEFAULTPTY)
return (NULL);
/*
* modify name based on minor number
*/
(void) snprintf(buf, sizeof (buf), "/dev/%cty%c%c",
prefix, 'p' + dmin / 16, "0123456789abcdef"[dmin % 16]);
if (stat64(buf, &stb) != 0)
return (NULL);
if (match_mask == MATCH_MM) {
if (stb.st_rdev == fsb->st_rdev)
return (buf);
} else if (stb.st_rdev == fsb->st_rdev &&
stb.st_dev == fsb->st_dev &&
stb.st_ino == fsb->st_ino)
return (buf);
return (NULL);
}
/*
* Converts a number to a string (null terminated).
*/
static void
itoa(int i, char *ptr)
{
int dig = 0;
int tempi;
tempi = i;
do {
dig++;
tempi /= 10;
} while (tempi);
ptr += dig;
*ptr = '\0';
while (--dig >= 0) {
*(--ptr) = i % 10 + '0';
i /= 10;
}
}
/*
* srch_dir() searches directory path and all directories under it up
* to depth directories deep for a file described by a stat structure
* fsb. It puts the answer into rbuf. If a match is found on device
* number only, the file name is put into dev_rbuf and dev_flag is set.
*
* srch_dir() returns 1 if a match (on device and inode) is found,
* or 0 otherwise.
*
*/
static int
srch_dir(const entry_t path, /* current path */
int match_mask, /* flags mask */
int depth, /* current depth (/dev = 0) */
const entry_t skip_dirs[], /* directories not needing searching */
struct stat64 *fsb) /* the file being searched for */
{
DIR *dirp;
struct dirent64 *direntp;
struct stat64 tsb;
char file_name[MAX_DEV_PATH];
entry_t file;
char *last_comp;
int found = 0;
int dirno = 0;
size_t path_len;
file.name = file_name;
file.flags = path.flags & match_mask;
if (file.flags == 0)
file.flags = match_mask;
/*
* do we need to search this directory? (always search /dev at depth 0)
*/
if ((skip_dirs != NULL) && (depth != 0))
while (skip_dirs[dirno].name != NULL)
if (strcmp(skip_dirs[dirno++].name, path.name) == 0)
return (0);
/*
* open directory
*/
if ((dirp = opendir(path.name)) == NULL) {
return (0);
}
path_len = strlen(path.name);
(void) strcpy(file_name, path.name);
last_comp = file_name + path_len;
*last_comp++ = '/';
/*
* read thru the directory
*/
while ((!found) && ((direntp = readdir64(dirp)) != NULL)) {
/*
* skip "." and ".." entries, if present
*/
if (direntp->d_name[0] == '.' &&
(strcmp(direntp->d_name, ".") == 0 ||
strcmp(direntp->d_name, "..") == 0))
continue;
/*
* if the file name (path + "/" + d_name + NULL) would be too
* long, skip it
*/
if ((path_len + strlen(direntp->d_name) + 2) > MAX_DEV_PATH)
continue;
(void) strcpy(last_comp, direntp->d_name);
if (stat64(file_name, &tsb) < 0)
continue;
/*
* skip "/dev/syscon" because it may be an invalid link after
* single user mode.
*/
if (strcmp(file_name, "/dev/syscon") == 0)
continue;
/*
* if a file is a directory and we are not too deep, recurse
*/
if ((tsb.st_mode & S_IFMT) == S_IFDIR)
if (depth < MAX_SRCH_DEPTH)
found = srch_dir(file, match_mask, depth+1,
skip_dirs, fsb);
else
continue;
/*
* else if it is not a directory, is it a character special
* file?
*/
else if ((tsb.st_mode & S_IFMT) == S_IFCHR) {
int flag = 0;
if (tsb.st_dev == fsb->st_dev)
flag |= MATCH_FS;
if (tsb.st_rdev == fsb->st_rdev)
flag |= MATCH_MM;
if (tsb.st_ino == fsb->st_ino)
flag |= MATCH_INO;
if ((flag & file.flags) == file.flags) {
(void) strcpy(rbuf, file.name);
found = 1;
} else if ((flag & (MATCH_MM | MATCH_FS)) ==
(MATCH_MM | MATCH_FS)) {
/*
* no (inodes do not match), but save the name
* for later
*/
(void) strcpy(dev_rbuf, file.name);
dev_flag = 1;
}
}
}
(void) closedir(dirp);
return (found);
}
/*
* get_pri_dirs() - returns a pointer to an array of strings, where each string
* is a priority directory name. The end of the array is marked by a NULL
* pointer. The priority directories' names are obtained from the file
* /etc/ttysrch if it exists and is readable, or if not, a default hard-coded
* list of directories.
*
* /etc/ttysrch, if used, is read in as a string of characters into memory and
* then parsed into strings of priority directory names, omitting comments and
* blank lines.
*
*/
#define START_STATE 1
#define COMMENT_STATE 2
#define DIRNAME_STATE 3
#define FLAG_STATE 4
#define CHECK_STATE 5
#define COMMENT_CHAR '#'
#define EOLN_CHAR '\n'
static const entry_t *
get_pri_dirs(void)
{
int fd, state;
size_t sz;
ssize_t size;
struct stat64 sb;
char *buf, *ebuf;
entry_t *vec;
/*
* if no /etc/ttysrch, use defaults
*/
if ((fd = open(TTYSRCH, 0)) < 0)
return (def_srch_dirs);
if (fstat64(fd, &sb) < 0) {
(void) close(fd);
return (def_srch_dirs);
}
sz = (size_t)sb.st_size;
if (dir_vec != NULL && sz == dir_size &&
sb.st_mtim.tv_sec == dir_mtim.tv_sec &&
sb.st_mtim.tv_nsec == dir_mtim.tv_nsec) {
/*
* size & modification time match
* no need to reread TTYSRCH
* just return old pointer
*/
(void) close(fd);
return (dir_vec);
}
buf = realloc(dir_buf, sz + 1);
if (buf != NULL) {
dir_buf = buf;
size = read(fd, dir_buf, sz);
}
(void) close(fd);
if (buf == NULL || size < 0) {
if (dir_vec != NULL) {
free(dir_vec);
dir_vec = NULL;
}
return ((entry_t *)def_srch_dirs);
}
dir_size = sz;
dir_mtim = sb.st_mtim;
/*
* ensure newline termination for buffer. Add an extra
* entry to dir_vec for null terminator
*/
ebuf = &dir_buf[size];
*ebuf++ = '\n';
for (sz = 1, buf = dir_buf; buf < ebuf; ++buf)
if (*buf == '\n')
++sz;
sz *= sizeof (*dir_vec);
vec = realloc(dir_vec, sz);
if (vec == NULL) {
if (dir_vec != NULL) {
free(dir_vec);
dir_vec = NULL;
}
return (def_srch_dirs);
}
dir_vec = vec;
state = START_STATE;
for (buf = dir_buf; buf < ebuf; ++buf) {
switch (state) {
case START_STATE:
if (*buf == COMMENT_CHAR) {
state = COMMENT_STATE;
break;
}
if (!isspace(*buf)) /* skip leading white space */
state = DIRNAME_STATE;
vec->name = buf;
vec->flags = 0;
break;
case COMMENT_STATE:
if (*buf == EOLN_CHAR)
state = START_STATE;
break;
case DIRNAME_STATE:
if (*buf == EOLN_CHAR) {
state = CHECK_STATE;
*buf = '\0';
} else if (isspace(*buf)) {
/* skip trailing white space */
state = FLAG_STATE;
*buf = '\0';
}
break;
case FLAG_STATE:
switch (*buf) {
case 'M':
vec->flags |= MATCH_MM;
break;
case 'F':
vec->flags |= MATCH_FS;
break;
case 'I':
vec->flags |= MATCH_INO;
break;
case EOLN_CHAR:
state = CHECK_STATE;
break;
}
break;
case CHECK_STATE:
if (strncmp(vec->name, DEV, strlen(DEV)) != 0) {
int tfd = open("/dev/console", O_WRONLY);
if (tfd >= 0) {
char buf[256];
(void) snprintf(buf, sizeof (buf),
_libc_gettext(
"ERROR: Entry '%s' in /etc/ttysrch ignored.\n"), vec->name);
(void) write(tfd, buf, strlen(buf));
(void) close(tfd);
}
} else {
char *slash;
slash = vec->name + strlen(vec->name) - 1;
while (*slash == '/')
*slash-- = '\0';
if (vec->flags == 0)
vec->flags = MATCH_ALL;
vec++;
}
state = START_STATE;
/*
* This state does not consume a character, so
* reposition the pointer.
*/
buf--;
break;
}
}
vec->name = NULL;
return (dir_vec);
}
char *
ttyname(int f)
{
char *ans = tsdalloc(_T_TTYNAME, MAX_DEV_PATH, NULL);
if (ans == NULL)
return (NULL);
return (ttyname_r(f, ans, MAX_DEV_PATH));
}