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/*
* Copyright 1998 by Albert Cahalan; all rights resered.
* This file may be used subject to the terms and conditions of the
* GNU Library General Public License Version 2, or any later version
* at your option, as published by the Free Software Foundation.
* 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 Library General Public License for more details.
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/sysmacros.h>
#include "devname.h"
#ifndef PAGE_SIZE
#define PAGE_SIZE (sizeof(long)*1024)
#endif
/* Who uses what:
*
* tty_to_dev oldps, w (there is a fancy version in ps)
* dev_to_tty oldps, top, ps
*/
typedef struct tty_map_node {
struct tty_map_node *next;
int major_number; /* not unsigned! Ugh... */
char name[4];
} tty_map_node;
static tty_map_node *tty_map = NULL;
/* Load /proc/tty/drivers for device name mapping use. */
static void load_drivers(void){
char buf[10000];
char *p;
int fd;
int bytes;
fd = open("/proc/tty/drivers",O_RDONLY);
if(fd == -1) goto fail;
bytes = read(fd, buf, 9999);
if(bytes == -1) goto fail;
buf[bytes] = '\0';
p = buf;
while(( p = strstr(p, " /dev/tty") )){
tty_map_node *tmn;
int len;
p += 9;
len = strspn(p, "ABCDEFGHIJKLMNOPQRSTUVWXYZ");
if(!len) continue;
if(len>3) continue;
if((len=1) && (*p=='S')) continue;
tmn = malloc(sizeof(tty_map_node));
tmn->next = tty_map;
tty_map = tmn;
memset(tmn->name, '\0', 4);
strncpy(tmn->name, p, len);
p += len;
tmn->major_number = atoi(p);
}
fail:
if(fd != -1) close(fd);
if(!tty_map) tty_map = (tty_map_node *)-1;
}
/* Try to guess the device name from /proc/tty/drivers info. */
static int driver_name(char * const buf, int maj, int min){
struct stat sbuf;
tty_map_node *tmn;
if(!tty_map) load_drivers();
if(tty_map == (tty_map_node *)-1) return 0;
tmn = tty_map;
for(;;){
if(!tmn) return 0;
if(tmn->major_number == maj) break;
tmn = tmn->next;
}
sprintf(buf, "/dev/tty%s%d", tmn->name, min); /* like "/dev/ttyZZ255" */
if(stat(buf, &sbuf) < 0) return 0;
if(min != minor(sbuf.st_rdev)) return 0;
if(maj != major(sbuf.st_rdev)) return 0;
return 1;
}
/* Try to guess the device name (we only need pre-2.2 devices) */
static int guess_name(char * const buf, int maj, int min){
struct stat sbuf;
int t0, t1;
int tmpmin = min;
switch(maj){
case 4:
if(min<64){
sprintf(buf, "/dev/tty%d", min);
break;
}
if(min<128){
sprintf(buf, "/dev/ttyS%d", min-64);
break;
}
tmpmin = min & 0x3f; /* FALL THROUGH */
case 3: /* /dev/[pt]ty[p-za-o][0-9a-z] is 936 */
t0 = "pqrstuvwxyzabcde"[tmpmin>>4];
t1 = "0123456789abcdef"[tmpmin&0x0f];
sprintf(buf, "/dev/tty%c%c", t0, t1);
break;
case 17: sprintf(buf, "/dev/ttyH%d", min); break;
case 19: sprintf(buf, "/dev/ttyC%d", min); break;
case 23: sprintf(buf, "/dev/ttyD%d", min); break;
case 24: sprintf(buf, "/dev/ttyE%d", min); break;
case 32: sprintf(buf, "/dev/ttyX%d", min); break;
case 43: sprintf(buf, "/dev/ttyI%d", min); break;
case 46: sprintf(buf, "/dev/ttyR%d", min); break;
case 48: sprintf(buf, "/dev/ttyL%d", min); break;
case 57: sprintf(buf, "/dev/ttyP%d", min); break;
case 71: sprintf(buf, "/dev/ttyF%d", min); break;
case 75: sprintf(buf, "/dev/ttyW%d", min); break;
case 78: sprintf(buf, "/dev/ttyM%d", min); break;
case 105: sprintf(buf, "/dev/ttyV%d", min); break;
/* 136 ... 143 are /dev/pts/0, /dev/pts/1, /dev/pts/2 ... */
case 136 ... 143: sprintf(buf, "/dev/pts/%d", min+(maj-136)*256); break;
default: return 0;
}
if(stat(buf, &sbuf) < 0) return 0;
if(min != minor(sbuf.st_rdev)) return 0;
if(maj != major(sbuf.st_rdev)) return 0;
return 1;
}
/* Linux 2.2 can give us filenames that might be correct.
* Useful names could be in /proc/PID/fd/2 (stderr, seldom redirected)
* and in /proc/PID/fd/255 (used by bash to remember the tty).
*/
static int link_name(char * const buf, int maj, int min, int pid, char *name){
struct stat sbuf;
char path[32];
int count;
sprintf(path, "/proc/%d/%s", pid, name); /* often permission denied */
count = readlink(path,buf,PAGE_SIZE);
if(count == -1) return 0;
buf[count] = '\0';
if(stat(buf, &sbuf) < 0) return 0;
if(min != minor(sbuf.st_rdev)) return 0;
if(maj != major(sbuf.st_rdev)) return 0;
return 1;
}
/* number --> name */
int dev_to_tty(char *ret, int chop, int dev, int pid, unsigned int flags) {
static char buf[PAGE_SIZE];
char *tmp = buf;
int i = 0;
int c;
if((short)dev == (short)-1) goto fail;
if( link_name(tmp, major(dev), minor(dev), pid, "tty" )) goto abbrev;
if( link_name(tmp, major(dev), minor(dev), pid, "fd/2" )) goto abbrev;
if( link_name(tmp, major(dev), minor(dev), pid, "fd/255")) goto abbrev;
if( guess_name(tmp, major(dev), minor(dev) )) goto abbrev;
if(driver_name(tmp, major(dev), minor(dev) )) goto abbrev;
fail:
strcpy(ret, "?");
return 1;
abbrev:
if((flags&ABBREV_DEV) && !strncmp(tmp,"/dev/",5) && tmp[5]) tmp += 5;
if((flags&ABBREV_TTY) && !strncmp(tmp,"tty", 3) && tmp[3]) tmp += 3;
if((flags&ABBREV_PTS) && !strncmp(tmp,"pts/", 4) && tmp[4]) tmp += 4;
tmp[chop] = '\0';
for(;;){
c = *tmp;
tmp++;
if(!c) break;
i++;
if(c<=' ') c = '?';
if(c>126) c = '?';
*ret = c;
ret++;
}
*ret = '\0';
return i;
}
/* name --> number */
int tty_to_dev(char *name) {
struct stat sbuf;
static char buf[32];
if(stat(name, &sbuf) >= 0) return sbuf.st_rdev;
snprintf(buf,32,"/dev/%s",name);
if(stat(buf, &sbuf) >= 0) return sbuf.st_rdev;
snprintf(buf,32,"/dev/tty%s",name);
if(stat(buf, &sbuf) >= 0) return sbuf.st_rdev;
snprintf(buf,32,"/dev/pts/%s",name);
if(stat(buf, &sbuf) >= 0) return sbuf.st_rdev;
return -1;
}
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