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author | Werner Fink | 2012-11-08 15:55:48 +0100 |
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committer | Karel Zak | 2012-11-08 15:55:48 +0100 |
commit | 3a08f74f1d9b85be4e7454daa15bf3c8413a69b5 (patch) | |
tree | 89dc5c47d0f5f575ca4460312877dc8245b8c154 /lib | |
parent | script: do not try to close stderr twice (diff) | |
download | kernel-qcow2-util-linux-3a08f74f1d9b85be4e7454daa15bf3c8413a69b5.tar.gz kernel-qcow2-util-linux-3a08f74f1d9b85be4e7454daa15bf3c8413a69b5.tar.xz kernel-qcow2-util-linux-3a08f74f1d9b85be4e7454daa15bf3c8413a69b5.zip |
lib/consoles: add code to detect all system consoles
Signed-off-by: Werner Fink <werner@suse.de>
Diffstat (limited to 'lib')
-rw-r--r-- | lib/Makemodule.am | 1 | ||||
-rw-r--r-- | lib/consoles.c | 508 |
2 files changed, 509 insertions, 0 deletions
diff --git a/lib/Makemodule.am b/lib/Makemodule.am index 91f857ad3..8e2b4eea4 100644 --- a/lib/Makemodule.am +++ b/lib/Makemodule.am @@ -27,6 +27,7 @@ libcommon_la_SOURCES = \ if LINUX libcommon_la_SOURCES += \ + lib/consoles.c \ lib/linux_version.c \ lib/loopdev.c endif diff --git a/lib/consoles.c b/lib/consoles.c new file mode 100644 index 000000000..d5d4f9702 --- /dev/null +++ b/lib/consoles.c @@ -0,0 +1,508 @@ +/* + * 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; +} + |