diff options
Diffstat (limited to 'drv_generic_serial.c')
| -rw-r--r-- | drv_generic_serial.c | 378 |
1 files changed, 378 insertions, 0 deletions
diff --git a/drv_generic_serial.c b/drv_generic_serial.c new file mode 100644 index 0000000..88ef87c --- /dev/null +++ b/drv_generic_serial.c @@ -0,0 +1,378 @@ +/* $Id: drv_generic_serial.c 890 2008-08-31 18:27:53Z sonic74 $ + * $URL: https://ssl.bulix.org/svn/lcd4linux/trunk/drv_generic_serial.c $ + * + * generic driver helper for serial and usbserial displays + * + * Copyright (C) 1999, 2000 Michael Reinelt <michael@reinelt.co.at> + * Copyright (C) 2004 The LCD4Linux Team <lcd4linux-devel@users.sourceforge.net> + * + * This file is part of LCD4Linux. + * + * LCD4Linux 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. + * + * LCD4Linux 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; if not, write to the Free Software + * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. + * + */ + +/* + * + * exported fuctions: + * + * int drv_generic_serial_open (char *section, char *driver, unsigned int flags) + * opens the serial port + * + * int drv_generic_serial_poll (char *string, int len) + * reads from the serial or USB port + * without retry + * + * int drv_generic_serial_read (char *string, int len); + * reads from the serial or USB port + * with retry + * + * void drv_generic_serial_write (char *string, int len); + * writes to the serial or USB port + * + * int drv_generic_serial_close (void); + * closes the serial port + * + */ + +#include "config.h" + +#include <stdlib.h> +#include <stdio.h> +#include <string.h> +#include <errno.h> +#include <unistd.h> +#include <termios.h> +#include <fcntl.h> +#include <time.h> +#include <signal.h> +#include <sys/types.h> +#include <sys/stat.h> + +#include "debug.h" +#include "qprintf.h" +#include "cfg.h" +#include "drv_generic_serial.h" + + +extern int got_signal; + +static char *Section; +static char *Driver; +static char *Port; +static speed_t Speed; +static int Device = -1; + + +#define LOCK "/var/lock/LCK..%s" + + +/****************************************/ +/*** generic serial/USB communication ***/ +/****************************************/ + +static pid_t drv_generic_serial_lock_port(const char *Port) +{ + char lockfile[256]; + char tempfile[256]; + char buffer[16]; + char *port, *p; + int fd, len, pid; + + if (strncmp(Port, "/dev/", 5) == 0) { + port = strdup(Port + 5); + } else { + port = strdup(Port); + } + + while ((p = strchr(port, '/')) != NULL) { + *p = '_'; + } + + qprintf(lockfile, sizeof(lockfile), LOCK, port); + qprintf(tempfile, sizeof(tempfile), LOCK, "TMP.XXXXXX"); + + free(port); + + if ((fd = mkstemp(tempfile)) == -1) { + error("mkstemp(%s) failed: %s", tempfile, strerror(errno)); + return -1; + } + + if (fchmod(fd, S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH) == -1) { + error("fchmod(%s) failed: %s", tempfile, strerror(errno)); + close(fd); + unlink(tempfile); + return -1; + } + + snprintf(buffer, sizeof(buffer), "%10d\n", (int) getpid()); + len = strlen(buffer); + if (write(fd, buffer, len) != len) { + error("write(%s) failed: %s", tempfile, strerror(errno)); + close(fd); + unlink(tempfile); + return -1; + } + close(fd); + + + while (link(tempfile, lockfile) == -1) { + + if (errno != EEXIST) { + error("link(%s, %s) failed: %s", tempfile, lockfile, strerror(errno)); + unlink(tempfile); + return -1; + } + + if ((fd = open(lockfile, O_RDONLY)) == -1) { + if (errno == ENOENT) + continue; /* lockfile disappared */ + error("open(%s) failed: %s", lockfile, strerror(errno)); + unlink(tempfile); + return -1; + } + + len = read(fd, buffer, sizeof(buffer) - 1); + if (len < 0) { + error("read(%s) failed: %s", lockfile, strerror(errno)); + unlink(tempfile); + return -1; + } + + buffer[len] = '\0'; + if (sscanf(buffer, "%d", &pid) != 1 || pid == 0) { + error("scan(%s) failed.", lockfile); + unlink(tempfile); + return -1; + } + + if (pid == getpid()) { + error("%s already locked by us. uh-oh...", lockfile); + unlink(tempfile); + return 0; + } + + if ((kill(pid, 0) == -1) && errno == ESRCH) { + error("removing stale lockfile %s", lockfile); + if (unlink(lockfile) == -1 && errno != ENOENT) { + error("unlink(%s) failed: %s", lockfile, strerror(errno)); + unlink(tempfile); + return pid; + } + continue; + } + unlink(tempfile); + return pid; + } + + unlink(tempfile); + return 0; +} + + +static pid_t drv_generic_serial_unlock_port(const char *Port) +{ + char lockfile[256]; + char *port, *p; + + if (strncmp(Port, "/dev/", 5) == 0) { + port = strdup(Port + 5); + } else { + port = strdup(Port); + } + + while ((p = strchr(port, '/')) != NULL) { + *p = '_'; + } + + qprintf(lockfile, sizeof(lockfile), LOCK, port); + unlink(lockfile); + free(port); + + return 0; +} + + +int drv_generic_serial_open(const char *section, const char *driver, const unsigned int flags) +{ + int i, fd; + pid_t pid; + struct termios portset; + + Section = (char *) section; + Driver = (char *) driver; + + Port = cfg_get(section, "Port", NULL); + if (Port == NULL || *Port == '\0') { + error("%s: no '%s.Port' entry from %s", Driver, section, cfg_source()); + return -1; + } + + if (cfg_number(section, "Speed", 19200, 1200, 230400, &i) < 0) + return -1; + switch (i) { + case 1200: + Speed = B1200; + break; + case 2400: + Speed = B2400; + break; + case 4800: + Speed = B4800; + break; + case 9600: + Speed = B9600; + break; + case 19200: + Speed = B19200; + break; + case 38400: + Speed = B38400; + break; + case 57600: + Speed = B57600; + break; + case 115200: + Speed = B115200; + break; +#ifdef B230400 + case 230400: + Speed = B230400; + break; +#endif + default: + error("%s: unsupported speed '%d' from %s", Driver, i, cfg_source()); + return -1; + } + + info("%s: using port '%s' at %d baud", Driver, Port, i); + + if ((pid = drv_generic_serial_lock_port(Port)) != 0) { + if (pid == -1) + error("%s: port %s could not be locked", Driver, Port); + else + error("%s: port %s is locked by process %d", Driver, Port, pid); + return -1; + } + + fd = open(Port, O_RDWR | O_NOCTTY | O_NDELAY); + if (fd == -1) { + error("%s: open(%s) failed: %s", Driver, Port, strerror(errno)); + drv_generic_serial_unlock_port(Port); + return -1; + } + + if (tcgetattr(fd, &portset) == -1) { + error("%s: tcgetattr(%s) failed: %s", Driver, Port, strerror(errno)); + drv_generic_serial_unlock_port(Port); + return -1; + } + + cfmakeraw(&portset); + portset.c_cflag |= flags; + cfsetispeed(&portset, Speed); + cfsetospeed(&portset, Speed); + if (tcsetattr(fd, TCSANOW, &portset) == -1) { + error("%s: tcsetattr(%s) failed: %s", Driver, Port, strerror(errno)); + drv_generic_serial_unlock_port(Port); + return -1; + } + + Device = fd; + return Device; +} + + +int drv_generic_serial_poll(char *string, const int len) +{ + int ret; + if (Device == -1) + return -1; + ret = read(Device, string, len); + if (ret < 0 && errno != EAGAIN) { + error("%s: read(%s) failed: %s", Driver, Port, strerror(errno)); + } + return ret; +} + + +int drv_generic_serial_read(char *string, const int len) +{ + int count, run, ret; + + count = len < 0 ? -len : len; + + for (run = 0; run < 10; run++) { + ret = drv_generic_serial_poll(string, count); + if (ret >= 0 || errno != EAGAIN) + break; + info("%s: read(%s): EAGAIN", Driver, Port); + usleep(1000); + } + + if (ret > 0 && ret != count && len > 0) { + error("%s: partial read(%s): len=%d ret=%d", Driver, Port, len, ret); + } + + return ret; +} + + +void drv_generic_serial_write(const char *string, const int len) +{ + static int error = 0; + int run, ret; + + if (Device == -1) { + error("%s: write to closed port %s failed!", Driver, Port); + return; + } + + for (run = 0; run < 10; run++) { + ret = write(Device, string, len); + if (ret >= 0 || errno != EAGAIN) { + break; + } + /* EAGAIN: retry 10 times, emit message after 2nd retry */ + if (run > 0) { + info("%s: write(%s): EAGAIN #%d", Driver, Port, run); + } + usleep(1000); + } + + if (ret < 0) { + error("%s: write(%s) failed: %s", Driver, Port, strerror(errno)); + if (++error > 10) { + error("%s: too much errors, giving up", Driver); + got_signal = -1; + } + } else if (ret != len) { + error("%s: partial write(%s): len=%d ret=%d", Driver, Port, len, ret); + } else { + error = 0; + } + return; +} + + +int drv_generic_serial_close(void) +{ + info("%s: closing port %s", Driver, Port); + close(Device); + drv_generic_serial_unlock_port(Port); + free(Port); + return 0; +} |