085231fbb
Denis Vlasenko
2007-01-10
Subject
code shrinkage by Bernhard Fischer
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Commit Diff GitHub →
sysklogd/logread.c+31 -49
| @@ -11,37 +11,30 @@ | |
| #include "busybox.h" | |
| #include <sys/ipc.h> | |
| - | //#include <sys/types.h> |
| #include <sys/sem.h> | |
| #include <sys/shm.h> | |
| - | //#include <signal.h> |
| - | //#include <setjmp.h> |
| #define DEBUG 0 | |
| - | static const long KEY_ID = 0x414e4547; /* "GENA" */ |
| + | enum { KEY_ID = 0x414e4547 }; /* "GENA" */ |
| static struct shbuf_ds { | |
| - | int32_t size; // size of data written |
| - | int32_t head; // start of message list |
| - | int32_t tail; // end of message list |
| - | char data[1]; // data/messages |
| - | } *buf; // shared memory pointer |
| - | |
| + | int32_t size; // size of data written |
| + | int32_t head; // start of message list |
| + | int32_t tail; // end of message list |
| + | char data[1]; // data/messages |
| + | } *buf; // 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 void error_exit(const char *str) ATTRIBUTE_NORETURN; | |
| static void error_exit(const char *str) | |
| { | |
| //release all acquired resources | |
| - | if (log_shmid != -1) |
| - | shmdt(buf); |
| + | shmdt(buf); |
| bb_perror_msg_and_die(str); | |
| } | |
| @@ -54,16 +47,7 @@ static void sem_up(int semid) | |
| error_exit("semop[SMrup]"); | |
| } | |
| - | /* |
| - | * sem_down - down()'s a semaphore |
| - | */ |
| - | static void sem_down(int semid) |
| - | { |
| - | if (semop(semid, SMrdn, 2) == -1) |
| - | error_exit("semop[SMrdn]"); |
| - | } |
| - | |
| - | static void interrupted(int sig) |
| + | static void interrupted(int sig ATTRIBUTE_UNUSED) |
| { | |
| signal(SIGINT, SIG_IGN); | |
| shmdt(buf); | |
| @@ -73,23 +57,18 @@ static void interrupted(int sig) | |
| int logread_main(int argc, char **argv) | |
| { | |
| int cur; | |
| - | int follow = 1; |
| - | |
| - | if (argc != 2 || argv[1][0]!='-' || argv[1][1]!='f' ) { |
| - | follow = 0; |
| - | /* no options, no getopt */ |
| - | if (argc > 1) |
| - | bb_show_usage(); |
| - | } |
| + | int log_semid; /* ipc semaphore id */ |
| + | int log_shmid; /* ipc shared memory id */ |
| + | smallint follow = getopt32(argc, argv, "f"); |
| log_shmid = shmget(KEY_ID, 0, 0); | |
| if (log_shmid == -1) | |
| - | error_exit("can't find circular buffer"); |
| + | bb_perror_msg_and_die("can't find syslogd buffer"); |
| // Attach shared memory to our char* | |
| buf = shmat(log_shmid, NULL, SHM_RDONLY); | |
| if (buf == NULL) | |
| - | error_exit("can't get access to syslogd buffer"); |
| + | bb_perror_msg_and_die("can't access syslogd buffer"); |
| log_semid = semget(KEY_ID, 0, 0); | |
| if (log_semid == -1) | |
| @@ -102,38 +81,42 @@ int logread_main(int argc, char **argv) | |
| cur = follow ? buf->tail : buf->head; | |
| do { | |
| - | #ifdef CONFIG_FEATURE_LOGREAD_REDUCED_LOCKING |
| + | #if ENABLE_FEATURE_LOGREAD_REDUCED_LOCKING |
| char *buf_data; | |
| int log_len, j; | |
| #endif | |
| - | sem_down(log_semid); |
| + | if (semop(log_semid, SMrdn, 2) == -1) |
| + | error_exit("semop[SMrdn]"); |
| if (DEBUG) | |
| - | printf("head:%i cur:%d tail:%i size:%i\n", buf->head, cur, buf->tail, buf->size); |
| + | printf("head:%i cur:%d tail:%i size:%i\n", |
| + | buf->head, cur, buf->tail, buf->size); |
| if (buf->head == buf->tail || cur == buf->tail) { | |
| if (follow) { | |
| sem_up(log_semid); | |
| - | sleep(1); /* TODO: replace me with a sleep_on */ |
| + | fflush(stdout); |
| + | sleep(1); /* TODO: replace me with a sleep_on */ |
| continue; | |
| - | } else { |
| - | printf("<empty syslog>\n"); |
| } | |
| + | puts("<empty syslog>"); |
| } | |
| // Read Memory | |
| - | #ifdef CONFIG_FEATURE_LOGREAD_REDUCED_LOCKING |
| + | #if ENABLE_FEATURE_LOGREAD_REDUCED_LOCKING |
| log_len = buf->tail - cur; | |
| if (log_len < 0) | |
| log_len += buf->size; | |
| buf_data = xmalloc(log_len); | |
| - | if (buf->tail >= cur) { |
| - | memcpy(buf_data, buf->data + cur, log_len); |
| - | } else { |
| - | memcpy(buf_data, buf->data + cur, buf->size - cur); |
| + | if (buf->tail >= cur) |
| + | j = log_len; |
| + | else |
| + | j = buf->size - cur; |
| + | memcpy(buf_data, buf->data + cur, j); |
| + | |
| + | if (buf->tail < cur) |
| memcpy(buf_data + buf->size - cur, buf->data, buf->tail); | |
| - | } |
| cur = buf->tail; | |
| #else | |
| while (cur != buf->tail) { | |
| @@ -146,16 +129,15 @@ int logread_main(int argc, char **argv) | |
| // release the lock on the log chain | |
| sem_up(log_semid); | |
| - | #ifdef CONFIG_FEATURE_LOGREAD_REDUCED_LOCKING |
| + | #if ENABLE_FEATURE_LOGREAD_REDUCED_LOCKING |
| for (j = 0; j < log_len; j += strlen(buf_data+j) + 1) { | |
| fputs(buf_data + j, stdout); | |
| } | |
| free(buf_data); | |
| #endif | |
| - | fflush(stdout); |
| } while (follow); | |
| shmdt(buf); | |
| - | return EXIT_SUCCESS; |
| + | fflush_stdout_and_exit(EXIT_SUCCESS); |
| } | |