--- /dev/null
+/*
+ * consoles.c Routines to detect the system consoles
+ *
+ * Copyright (c) 2011 SuSE LINUX Products GmbH, All rights reserved.
+ *
+ * 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 2, 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 (see the file COPYING); if not, write to the
+ * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston,
+ * MA 02110-1301, USA.
+ *
+ * Author: Werner Fink <werner@suse.de>
+ */
+
+#include <limits.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/ioctl.h>
+#ifdef __linux__
+# include <sys/vt.h>
+# include <sys/kd.h>
+# include <linux/serial.h>
+#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__
+# endif
+# ifndef restrict
+# define restrict __restrict__
+# endif
+#endif
+
+#define alignof(type) ((sizeof(type)+(sizeof(void*)-1)) & ~(sizeof(void*)-1))
+
+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 below
+ * /sys/class/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 below
+ * /sys/class/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__ */
+
+/*
+ * Search below /dev for the characer device in
+ * the local `dev_t comparedev' variable.
+ */
+static dev_t comparedev;
+static
+#ifdef __GNUC__
+__attribute__((__nonnull__,__malloc__,__hot__))
+#endif
+char* scandev(DIR *dir)
+{
+ char *name = (char*)0;
+ struct dirent *dent;
+ int fd;
+
+ fd = dirfd(dir);
+ rewinddir(dir);
+ while ((dent = readdir(dir))) {
+ char path[PATH_MAX];
+ struct stat st;
+ if (fstatat(fd, dent->d_name, &st, 0) < 0)
+ continue;
+ if (!S_ISCHR(st.st_mode))
+ continue;
+ if (comparedev != st.st_rdev)
+ continue;
+ if ((size_t)snprintf(path, sizeof(path), "/dev/%s", dent->d_name) >= sizeof(path))
+ continue;
+ name = realpath(path, NULL);
+ break;
+ }
+ return name;
+}
+
+/*
+ * Default control characters for an unknown terminal line.
+ */
+static
+struct chardata initcp = {
+ CERASE,
+ CKILL,
+ CTRL('r'),
+ 0
+};
+
+/*
+ * Allocate an aligned `struct console' memory area,
+ * initialize its default values, and append it to
+ * the global linked list.
+ */
+
+static int concount; /* Counter for console IDs */
+
+static
+#ifdef __GNUC__
+__attribute__((__nonnull__,__hot__))
+#endif
+void consalloc(char * name)
+{
+ struct console *restrict tail;
+
+ if (posix_memalign((void*)&tail, sizeof(void*), alignof(typeof(struct console))) != 0)
+ perror("memory allocation");
+
+ 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;
+}
+
+/*
+ * Try to detect the real device(s) used for the system console
+ * /dev/console if but only if /dev/console is used. On Linux
+ * this can be more than one device, e.g. a serial line as well
+ * as a virtual console as well as a simple printer.
+ *
+ * Returns 1 if stdout and stderr should be reconnected and 0
+ * otherwise.
+ */
+int detect_consoles(const char *device, int fallback)
+{
+ int fd, ret = 0;
+#ifdef __linux__
+ char *attrib, *cmdline;
+ FILE *fc;
+#endif
+ if (!device || *device == '\0')
+ fd = dup(fallback);
+ else {
+ fd = open(device, O_RDWR|O_NONBLOCK|O_NOCTTY|O_CLOEXEC);
+ ret = 1;
+ }
+
+ if (fd >= 0) {
+ DIR *dir;
+ char *name;
+ struct stat st;
+#ifdef TIOCGDEV
+ unsigned int devnum;
+#endif
+
+ if (fstat(fd, &st) < 0) {
+ close(fd);
+ goto fallback;
+ }
+ comparedev = st.st_rdev;
+
+ if (ret && (fstat(fallback, &st) < 0 || comparedev != st.st_rdev))
+ dup2(fd, fallback);
+#ifdef __linux__
+ /*
+ * Check if the device detection for Linux system console should be used.
+ */
+ if (comparedev == makedev(TTYAUX_MAJOR, 0)) { /* /dev/tty */
+ close(fd);
+ device = "/dev/tty";
+ goto fallback;
+ }
+ if (comparedev == makedev(TTYAUX_MAJOR, 1)) { /* /dev/console */
+ close(fd);
+ goto console;
+ }
+ if (comparedev == makedev(TTYAUX_MAJOR, 2)) { /* /dev/ptmx */
+ close(fd);
+ device = "/dev/tty";
+ goto fallback;
+ }
+ if (comparedev == makedev(TTY_MAJOR, 0)) { /* /dev/tty0 */
+ struct vt_stat vt;
+ if (ioctl(fd, VT_GETSTATE, &vt) < 0) {
+ close(fd);
+ goto fallback;
+ }
+ comparedev = makedev(TTY_MAJOR, (int)vt.v_active);
+ }
+#endif
+#ifdef TIOCGDEV
+ if (ioctl (fd, TIOCGDEV, &devnum) < 0) {
+ close(fd);
+ goto fallback;
+ }
+ comparedev = (dev_t)devnum;
+#endif
+ close(fd);
+ dir = opendir("/dev");
+ if (!dir)
+ goto fallback;
+ name = scandev(dir);
+ if (name)
+ consalloc(name);
+ closedir(dir);
+ if (!consoles)
+ goto fallback;
+ return ret;
+ }
+#ifdef __linux__
+console:
+ /*
+ * Detection of devices used for Linux system consolei using
+ * the /proc/consoles API with kernel 2.6.38 and higher.
+ */
+ if ((fc = fopen("/proc/consoles", "re"))) {
+ char fbuf[16];
+ int maj, min;
+ DIR *dir;
+ dir = opendir("/dev");
+ if (!dir) {
+ fclose(fc);
+ goto fallback;
+ }
+ 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);
+ fclose(fc);
+ return ret;
+ }
+ /*
+ * Detection of devices used for Linux system console using
+ * the sysfs /sys/class/tty/ API with kernel 2.6.37 and higher.
+ */
+ if ((attrib = actattr("console"))) {
+ char *words = attrib, *token;
+ DIR *dir;
+
+ dir = opendir("/dev");
+ if (!dir) {
+ free(attrib);
+ goto fallback;
+ }
+ 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);
+ free(attrib);
+ if (!consoles)
+ goto fallback;
+ return ret;
+
+ }
+ /*
+ * Detection of devices used for Linux system console using
+ * kernel parameter on the kernels command line.
+ */
+ if ((cmdline = oneline("/proc/cmdline"))) {
+ char *words= cmdline, *token;
+ DIR *dir;
+
+ dir = opendir("/dev");
+ if (!dir) {
+ free(cmdline);
+ goto fallback;
+ }
+ while ((token = strsep(&words, " \t\r\n"))) {
+#ifdef TIOCGDEV
+ unsigned int devnum;
+#else
+ struct vt_stat vt;
+ struct stat st;
+#endif
+ char *colon, *name;
+
+ 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);
+ free(cmdline);
+ /*
+ * Detection of the device used for Linux system console using
+ * the ioctl TIOCGDEV if available (e.g. official 2.6.38).
+ */
+ if (!consoles) {
+#ifdef TIOCGDEV
+ unsigned int devnum;
+ const char *name;
+
+ if (!device || *device == '\0')
+ fd = dup(fallback);
+ else fd = open(device, O_RDWR|O_NONBLOCK|O_NOCTTY|O_CLOEXEC);
+
+ if (fd < 0)
+ goto fallback;
+
+ if (ioctl (fd, TIOCGDEV, &devnum) < 0) {
+ close(fd);
+ goto fallback;
+ }
+ comparedev = (dev_t)devnum;
+ close(fd);
+
+ if (device && *device != '\0')
+ name = device;
+ else name = ttyname(fallback);
+
+ if (!name)
+ name = "/dev/tty1";
+
+ consalloc(strdup(name));
+ if (consoles) {
+ if (!device || *device == '\0')
+ consoles->fd = fallback;
+ return ret;
+ }
+#endif
+ goto fallback;
+ }
+ return ret;
+ }
+#endif /* __linux __ */
+fallback:
+ if (fallback >= 0) {
+ const char *name;
+
+ if (device && *device != '\0')
+ name = device;
+ else name = ttyname(fallback);
+
+ if (!name)
+ name = "/dev/tty";
+
+ consalloc(strdup(name));
+ if (consoles)
+ consoles->fd = fallback;
+ }
+ return ret;
+}
+
projects / thirdparty / util-linux.git / commitdiff
