Enhance src/consoles.c and src/consoles.h to reflect latest

linux kernel possiblities to detect the devices used for
the system console /dev/console
This commit is contained in:
Werner Fink 2011-03-31 12:25:34 +00:00
parent d9122565a0
commit 43bc53af8d
2 changed files with 327 additions and 22 deletions

View File

@ -27,9 +27,23 @@
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#ifdef __linux__
# ifndef TIOCGDEV
# include <sys/vt.h>
# include <sys/kd.h>
# include <linux/serial.h>
# endif
#endif
#include <fcntl.h>
#include <dirent.h>
#include <unistd.h>
#include "consoles.h"
#ifdef __linux__
# include <linux/major.h>
#endif
#if !defined(__STDC_VERSION__) || (__STDC_VERSION__ < 199901L)
# ifndef typeof
# define typeof __typeof__
@ -43,8 +57,93 @@
struct console *consoles;
/*
* Read and allocate one line from file,
* the caller has to free the result
*/
static
#ifdef __GNUC__
__attribute__((__nonnull__))
#endif
char *oneline(const char *file)
{
FILE *fp;
char *ret = (char*)0, *nl;
size_t len = 0;
if ((fp = fopen(file, "re")) == (FILE*)0)
goto err;
if (getline(&ret, &len, fp) < 0)
goto out;
if (len)
ret[len-1] = '\0';
if ((nl = strchr(ret, '\n')))
*nl = '\0';
out:
fclose(fp);
err:
return ret;
}
#ifdef __linux__
/*
* Read and determine active attribute for tty,
* the caller has to free the result.
*/
static
__attribute__((__malloc__))
char *actattr(const char *tty)
{
char *ret = (char*)0;
char *path;
if (!tty || *tty == '\0')
goto err;
if (asprintf(&path, "/sys/class/tty/%s/active", tty) < 0)
goto err;
if ((ret = oneline(path)) == (char*)0)
goto out;
out:
free(path);
err:
return ret;
}
/* Read and determine device attribute for tty */
static
dev_t devattr(const char *tty)
{
unsigned int maj, min;
dev_t dev = 0;
char *path, *value;
if (!tty || *tty == '\0')
goto err;
if (asprintf(&path, "/sys/class/tty/%s/dev", tty) < 0)
goto err;
if ((value = oneline(path)) == (char*)0)
goto out;
if (sscanf(value, "%u:%u", &maj, &min) == 2)
dev = makedev(maj, min);
free(value);
out:
free(path);
err:
return dev;
}
#endif /* __linux__ */
static dev_t comparedev;
static char* scandev(DIR *dir)
static
#ifdef __GNUC__
__attribute__((__nonnull__,__malloc__,__hot__))
#endif
char* scandev(DIR *dir)
{
char *name = (char*)0;
struct dirent *dent;
@ -69,27 +168,23 @@ static char* scandev(DIR *dir)
return name;
}
void detect_consoles(void)
static
struct chardata initcp = {
CERASE,
CKILL,
CTRL('r'),
0
};
static int concount; /* Counter for console IDs */
static
#ifdef __GNUC__
__attribute__((__nonnull__,__hot__))
#endif
void consalloc(char * name)
{
FILE *fc;
if ((fc = fopen("/proc/consoles", "r"))) {
char fbuf[16];
int maj, min;
DIR *dir;
dir = opendir("/dev");
if (!dir)
goto out;
while ((fscanf(fc, "%*s %*s (%[^)]) %d:%d", &fbuf[0], &maj, &min) == 3)) {
struct console *restrict tail;
char * name;
if (!strchr(fbuf, 'E'))
continue;
comparedev = makedev(maj, min);
name = scandev(dir);
if (!name)
continue;
if (posix_memalign((void*)&tail, sizeof(void*), alignof(typeof(struct console))) != 0)
perror("memory allocation");
@ -97,13 +192,208 @@ void detect_consoles(void)
tail->next = (struct console*)0;
tail->tty = name;
tail->file = (FILE*)0;
tail->flags = 0;
tail->fd = -1;
tail->id = concount++;
tail->pid = 0;
memset(&tail->tio, 0, sizeof(tail->tio));
memcpy(&tail->cp, &initcp, sizeof(struct chardata));
if (!consoles)
consoles = tail;
else
consoles->next = tail;
}
void detect_consoles(const char *console, int fallback)
{
#ifdef __linux__
char *attrib, *cmdline;
FILE *fc;
if ((fc = fopen("/proc/consoles", "re"))) {
char fbuf[16];
int maj, min;
DIR *dir;
dir = opendir("/dev");
if (!dir)
goto out1;
while ((fscanf(fc, "%*s %*s (%[^)]) %d:%d", &fbuf[0], &maj, &min) == 3)) {
char * name;
if (!strchr(fbuf, 'E'))
continue;
comparedev = makedev(maj, min);
name = scandev(dir);
if (!name)
continue;
consalloc(name);
}
closedir(dir);
out:
out1:
fclose(fc);
return;
}
if ((attrib = actattr("console"))) {
char *words = attrib, *token;
DIR *dir;
dir = opendir("/dev");
if (!dir)
goto out2;
while ((token = strsep(&words, " \t\r\n"))) {
char * name;
if (*token == '\0')
continue;
comparedev = devattr(token);
if (comparedev == makedev(TTY_MAJOR, 0)) {
char *tmp = actattr(token);
if (!tmp)
continue;
comparedev = devattr(tmp);
free(tmp);
}
name = scandev(dir);
if (!name)
continue;
consalloc(name);
}
closedir(dir);
out2:
free(attrib);
return;
}
if ((cmdline = oneline("/proc/cmdline"))) {
char *words= cmdline, *token;
DIR *dir;
dir = opendir("/dev");
if (!dir)
goto out3;
while ((token = strsep(&words, " \t\r\n"))) {
#ifdef TIOCGDEV
unsigned int devnum;
#else
struct vt_stat vt;
struct stat st;
#endif
char *colon, *name;
int fd;
if (*token != 'c')
continue;
if (strncmp(token, "console=", 8) != 0)
continue;
token += 8;
if (strcmp(token, "brl") == 0)
token += 4;
if ((colon = strchr(token, ',')))
*colon = '\0';
if (asprintf(&name, "/dev/%s", token) < 0)
continue;
if ((fd = open(name, O_RDWR|O_NONBLOCK|O_NOCTTY|O_CLOEXEC)) < 0) {
free(name);
continue;
}
free(name);
#ifdef TIOCGDEV
if (ioctl (fd, TIOCGDEV, &devnum) < 0) {
close(fd);
continue;
}
comparedev = (dev_t)devnum;
#else
if (fstat(fd, &st) < 0) {
close(fd);
continue;
}
comparedev = st.st_rdev;
if (comparedev == makedev(TTY_MAJOR, 0)) {
if (ioctl(fd, VT_GETSTATE, &vt) < 0) {
close(fd);
continue;
}
comparedev = makedev(TTY_MAJOR, (int)vt.v_active);
}
#endif
close(fd);
name = scandev(dir);
if (!name)
continue;
consalloc(name);
}
closedir(dir);
out3:
free(cmdline);
return;
}
#endif /* __linux __ */
if (console && *console) {
int fd;
DIR *dir;
char *name;
#ifdef TIOCGDEV
unsigned int devnum;
#else
# ifdef __linux__
struct vt_stat vt;
# endif
struct stat st;
#endif
if ((fd = open(console, O_RDWR|O_NONBLOCK|O_NOCTTY|O_CLOEXEC)) < 0)
return;
#ifdef TIOCGDEV
if (ioctl (fd, TIOCGDEV, &devnum) < 0) {
close(fd);
return;
}
comparedev = (dev_t)devnum;
#else
if (fstat(fd, &st) < 0) {
close(fd);
return;
}
# ifdef __linux__
comparedev = st.st_rdev;
if (comparedev == makedev(TTY_MAJOR, 0)) {
if (ioctl(fd, VT_GETSTATE, &vt) < 0) {
close(fd);
return;
}
comparedev = makedev(TTY_MAJOR, (int)vt.v_active);
}
# endif
#endif
close(fd);
dir = opendir("/dev");
if (!dir)
return;
name = scandev(dir);
if (name)
consalloc(name);
closedir(dir);
return;
}
if (fallback >= 0) {
const char *name = ttyname(fallback);
if (!name)
name = "/dev/console";
consalloc(strdup(name));
if (consoles)
consoles->fd = fallback;
}
}

View File

@ -21,13 +21,28 @@
* Author: Werner Fink <werner@suse.de>
*/
#include <sys/types.h>
#include <stdint.h>
#include <stdio.h>
#include <termios.h>
struct chardata {
uint8_t erase;
uint8_t kill;
uint8_t eol;
uint8_t parity;
};
struct console {
char *tty;
int tlock;
struct termios ltio, otio;
FILE *file;
uint32_t flags;
int fd, id;
#define CON_SERIAL 0x0001
#define CON_NOTTY 0x0002
pid_t pid;
struct chardata cp;
struct termios tio;
struct console *next;
};
extern struct console *consoles;
extern void detect_consoles(void);
extern void detect_consoles(const char *console, int fallback);