From 4aca87515a5083ae0e31ce3177189fd43b6d05ac Mon Sep 17 00:00:00 2001 From: Andreas Baumann Date: Sat, 3 Jan 2015 13:58:15 +0100 Subject: patch to Vanilla Tomato 1.28 --- release/src/router/busybox/sysklogd/logread.c | 262 +++++++++++++++----------- 1 file changed, 155 insertions(+), 107 deletions(-) (limited to 'release/src/router/busybox/sysklogd/logread.c') diff --git a/release/src/router/busybox/sysklogd/logread.c b/release/src/router/busybox/sysklogd/logread.c index 2692efbe..603a3776 100644 --- a/release/src/router/busybox/sysklogd/logread.c +++ b/release/src/router/busybox/sysklogd/logread.c @@ -6,132 +6,180 @@ * * Maintainer: Gennady Feldman as of Mar 12, 2001 * - * 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 of the License, 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; if not, write to the Free Software - * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA - * 02111-1307 USA - * + * Licensed under GPLv2 or later, see file LICENSE in this tarball for details. */ - -#include -#include -#include +#include "libbb.h" #include -#include #include #include -#include -#include -#include "busybox.h" - -static const long KEY_ID = 0x414e4547; /*"GENA"*/ - -static struct shbuf_ds { - int size; // size of data written - int head; // start of message list - int tail; // end of message list - char data[1]; // data/messages -} *buf = NULL; // shared memory pointer - -// Semaphore operation structures -static struct sembuf SMrup[1] = {{0, -1, IPC_NOWAIT | SEM_UNDO}}; // set SMrup -static struct sembuf SMrdn[2] = {{1, 0}, {0, +1, SEM_UNDO}}; // set SMrdn - -static int log_shmid = -1; // ipc shared memory id -static int log_semid = -1; // ipc semaphore id -static jmp_buf jmp_env; - -static void error_exit(const char *str); -static void interrupted(int sig); +#define DEBUG 0 + +/* our shared key (syslogd.c and logread.c must be in sync) */ +enum { KEY_ID = 0x414e4547 }; /* "GENA" */ + +struct shbuf_ds { + int32_t size; // size of data - 1 + int32_t tail; // end of message list + char data[1]; // messages +}; + +static const struct sembuf init_sem[3] = { + {0, -1, IPC_NOWAIT | SEM_UNDO}, + {1, 0}, {0, +1, SEM_UNDO} +}; + +struct globals { + struct sembuf SMrup[1]; // {0, -1, IPC_NOWAIT | SEM_UNDO}, + struct sembuf SMrdn[2]; // {1, 0}, {0, +1, SEM_UNDO} + struct shbuf_ds *shbuf; +}; +#define G (*(struct globals*)&bb_common_bufsiz1) +#define SMrup (G.SMrup) +#define SMrdn (G.SMrdn) +#define shbuf (G.shbuf) +#define INIT_G() do { \ + memcpy(SMrup, init_sem, sizeof(init_sem)); \ +} while (0) + +static void error_exit(const char *str) NORETURN; +static void error_exit(const char *str) +{ + //release all acquired resources + shmdt(shbuf); + bb_perror_msg_and_die(str); +} /* * sem_up - up()'s a semaphore. */ -static inline void sem_up(int semid) +static void sem_up(int semid) { - if ( semop(semid, SMrup, 1) == -1 ) + if (semop(semid, SMrup, 1) == -1) error_exit("semop[SMrup]"); } -/* - * sem_down - down()'s a semaphore - */ -static inline void sem_down(int semid) +static void interrupted(int sig UNUSED_PARAM) { - if ( semop(semid, SMrdn, 2) == -1 ) - error_exit("semop[SMrdn]"); + signal(SIGINT, SIG_IGN); + shmdt(shbuf); + exit(EXIT_SUCCESS); } -extern int logread_main(int argc, char **argv) +int logread_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; +int logread_main(int argc UNUSED_PARAM, char **argv) { - int i; - - /* no options, no getopt */ - if (argc > 1) - bb_show_usage(); - - // handle intrrupt signal - if (setjmp(jmp_env)) goto output_end; - - // attempt to redefine ^C signal - signal(SIGINT, interrupted); - - if ( (log_shmid = shmget(KEY_ID, 0, 0)) == -1) - error_exit("Can't find circular buffer"); - - // Attach shared memory to our char* - if ( (buf = shmat(log_shmid, NULL, SHM_RDONLY)) == NULL) - error_exit("Can't get access to circular buffer from syslogd"); - - if ( (log_semid = semget(KEY_ID, 0, 0)) == -1) - error_exit("Can't get access to semaphone(s) for circular buffer from syslogd"); - - sem_down(log_semid); - // Read Memory - i=buf->head; - - //printf("head: %i tail: %i size: %i\n",buf->head,buf->tail,buf->size); - if (buf->head == buf->tail) { - printf("\n"); - } - - while ( i != buf->tail) { - printf("%s", buf->data+i); - i+= strlen(buf->data+i) + 1; - if (i >= buf->size ) - i=0; - } - sem_up(log_semid); - -output_end: - if (log_shmid != -1) - shmdt(buf); - - return EXIT_SUCCESS; -} + unsigned cur; + int log_semid; /* ipc semaphore id */ + int log_shmid; /* ipc shared memory id */ + smallint follow = getopt32(argv, "f"); -static void interrupted(int sig){ - signal(SIGINT, SIG_IGN); - longjmp(jmp_env, 1); -} + INIT_G(); -static void error_exit(const char *str){ - perror(str); - //release all acquired resources - if (log_shmid != -1) - shmdt(buf); + log_shmid = shmget(KEY_ID, 0, 0); + if (log_shmid == -1) + bb_perror_msg_and_die("can't find syslogd buffer"); + + /* Attach shared memory to our char* */ + shbuf = shmat(log_shmid, NULL, SHM_RDONLY); + if (shbuf == NULL) + bb_perror_msg_and_die("can't access syslogd buffer"); + + log_semid = semget(KEY_ID, 0, 0); + if (log_semid == -1) + error_exit("can't get access to semaphores for syslogd buffer"); + + signal(SIGINT, interrupted); - exit(1); + /* Suppose atomic memory read */ + /* Max possible value for tail is shbuf->size - 1 */ + cur = shbuf->tail; + + /* Loop for logread -f, one pass if there was no -f */ + do { + unsigned shbuf_size; + unsigned shbuf_tail; + const char *shbuf_data; +#if ENABLE_FEATURE_LOGREAD_REDUCED_LOCKING + int i; + int len_first_part; + int len_total = len_total; /* for gcc */ + char *copy = copy; /* for gcc */ +#endif + if (semop(log_semid, SMrdn, 2) == -1) + error_exit("semop[SMrdn]"); + + /* Copy the info, helps gcc to realize that it doesn't change */ + shbuf_size = shbuf->size; + shbuf_tail = shbuf->tail; + shbuf_data = shbuf->data; /* pointer! */ + + if (DEBUG) + printf("cur:%d tail:%i size:%i\n", + cur, shbuf_tail, shbuf_size); + + if (!follow) { + /* advance to oldest complete message */ + /* find NUL */ + cur += strlen(shbuf_data + cur); + if (cur >= shbuf_size) { /* last byte in buffer? */ + cur = strnlen(shbuf_data, shbuf_tail); + if (cur == shbuf_tail) + goto unlock; /* no complete messages */ + } + /* advance to first byte of the message */ + cur++; + if (cur >= shbuf_size) /* last byte in buffer? */ + cur = 0; + } else { /* logread -f */ + if (cur == shbuf_tail) { + sem_up(log_semid); + fflush(stdout); + sleep(1); /* TODO: replace me with a sleep_on */ + continue; + } + } + + /* Read from cur to tail */ +#if ENABLE_FEATURE_LOGREAD_REDUCED_LOCKING + len_first_part = len_total = shbuf_tail - cur; + if (len_total < 0) { + /* message wraps: */ + /* [SECOND PART.........FIRST PART] */ + /* ^data ^tail ^cur ^size */ + len_total += shbuf_size; + } + copy = xmalloc(len_total + 1); + if (len_first_part < 0) { + /* message wraps (see above) */ + len_first_part = shbuf_size - cur; + memcpy(copy + len_first_part, shbuf_data, shbuf_tail); + } + memcpy(copy, shbuf_data + cur, len_first_part); + copy[len_total] = '\0'; + cur = shbuf_tail; +#else + while (cur != shbuf_tail) { + fputs(shbuf_data + cur, stdout); + cur += strlen(shbuf_data + cur) + 1; + if (cur >= shbuf_size) + cur = 0; + } +#endif + unlock: + /* release the lock on the log chain */ + sem_up(log_semid); + +#if ENABLE_FEATURE_LOGREAD_REDUCED_LOCKING + for (i = 0; i < len_total; i += strlen(copy + i) + 1) { + fputs(copy + i, stdout); + } + free(copy); +#endif + } while (follow); + + shmdt(shbuf); + + fflush_stdout_and_exit(EXIT_SUCCESS); } -- cgit v1.2.3-54-g00ecf