new libbb func: xmalloc_realpath (+ use it where makes sense)

syslogd, logread: add debugging code (disabled)
syslogs: drastically smaller bss; fix "-C n" behaviour

coreutils/realpath.c

@@ -10,8 +10,6 @@
  * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
  */
 
-#include <limits.h>
-#include <stdlib.h>
 #include "busybox.h"
 
 int realpath_main(int argc, char **argv)

include/libbb.h

@@ -238,6 +238,7 @@ extern DIR *warn_opendir(const char *path);
 
 char *xgetcwd(char *cwd);
 char *xreadlink(const char *path);
+char *xmalloc_realpath(const char *path);
 extern void xstat(char *filename, struct stat *buf);
 extern pid_t spawn(char **argv);
 extern pid_t xspawn(char **argv);

include/usage.h

@@ -3021,7 +3021,8 @@
        "\n	-R HOST[:PORT]	Log to IP or hostname on PORT (default PORT=514/UDP)" \
        "\n	-L	Log locally and via network logging (default is network only)") \
 	USE_FEATURE_IPC_SYSLOG( \
-       "\n	-C [size(KiB)]	Log to a circular buffer (read the buffer using logread)")
+       "\n	-C[size(KiB)]	Log to a circular buffer (read the buffer using logread)")
+	/* NB: -Csize shouldn't have space (because size is optional) */
 #define syslogd_example_usage \
        "$ syslogd -R masterlog:514\n" \
        "$ syslogd -R 192.168.1.1:601\n"

libbb/xreadlink.c

@@ -4,16 +4,13 @@
  *  Returns a NULL on failure...
  */
 
-#include <stdio.h>
+#include "libbb.h"
 
 /*
  * NOTE: This function returns a malloced char* that you will have to free
  * yourself. You have been warned.
  */
 
-#include <unistd.h>
-#include "libbb.h"
-
 char *xreadlink(const char *path)
 {
 	enum { GROWBY = 80 }; /* how large we will grow strings by */
@@ -36,3 +33,16 @@ char *xreadlink(const char *path)
 
 	return buf;
 }
+
+char *xmalloc_realpath(const char *path)
+{
+#ifdef __GLIBC__
+	/* glibc provides a non-standard extension */
+	return realpath(path, NULL);
+#else
+	char buf[PATH_MAX+1];
+
+	/* on error returns NULL (xstrdup(NULL) ==NULL) */
+	return xstrdup(realpath(path, buf));
+#endif
+}

sysklogd/logread.c

@@ -9,46 +9,48 @@
  * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
  */
 
-
 #include "busybox.h"
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
 #include <sys/ipc.h>
-#include <sys/types.h>
+//#include <sys/types.h>
 #include <sys/sem.h>
 #include <sys/shm.h>
-#include <signal.h>
+//#include <signal.h>
-#include <setjmp.h>
+//#include <setjmp.h>
-#include <unistd.h>
 
-static const long KEY_ID = 0x414e4547; /*"GENA"*/
+#define DEBUG 0
+
+static const long KEY_ID = 0x414e4547; /* "GENA" */
 
 static struct shbuf_ds {
-	int size;		// size of data written
+	int32_t size;		// size of data written
-	int head;		// start of message list
+	int32_t head;		// start of message list
-	int tail;		// end of message list
+	int32_t tail;		// end of message list
 	char data[1];		// data/messages
-} *buf = NULL;			// shared memory pointer
+} *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_shmid = -1;	// ipc shared memory id
-static int	log_semid = -1;	// ipc semaphore id
+static int log_semid = -1;	// ipc semaphore id
-static jmp_buf	jmp_env;
 
-static void error_exit(const char *str);
+static void error_exit(const char *str) ATTRIBUTE_NORETURN;
-static void interrupted(int sig);
+static void error_exit(const char *str)
+{
+	//release all acquired resources
+	if (log_shmid != -1)
+		shmdt(buf);
+	bb_perror_msg_and_die(str);
+}
 
 /*
  * sem_up - up()'s a semaphore.
  */
 static void sem_up(int semid)
 {
-	if ( semop(semid, SMrup, 1) == -1 )
+	if (semop(semid, SMrup, 1) == -1)
 		error_exit("semop[SMrup]");
 }
 
@@ -57,52 +59,59 @@ static void sem_up(int semid)
  */
 static void sem_down(int semid)
 {
-	if ( semop(semid, SMrdn, 2) == -1 )
+	if (semop(semid, SMrdn, 2) == -1)
 		error_exit("semop[SMrdn]");
 }
 
+static void interrupted(int sig)
+{
+	signal(SIGINT, SIG_IGN);
+	shmdt(buf);
+	exit(0);
+}
+
 int logread_main(int argc, char **argv)
 {
-	int i;
+	int cur;
-	int follow=0;
+	int follow = 1;
 
-	if (argc == 2 && argv[1][0]=='-' && argv[1][1]=='f') {
+	if (argc != 2 || argv[1][0]!='-' || argv[1][1]!='f' ) {
-		follow = 1;
+		follow = 0;
-	} else {
 		/* no options, no getopt */
 		if (argc > 1)
 			bb_show_usage();
 	}
 
-	// handle interrupt signal
+	log_shmid = shmget(KEY_ID, 0, 0);
-	if (setjmp(jmp_env)) goto output_end;
+	if (log_shmid == -1)
+		error_exit("can't find circular 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");
+
+	log_semid = semget(KEY_ID, 0, 0);
+	if (log_semid == -1)
+		error_exit("can't get access to semaphores for syslogd buffer");
 
 	// 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 semaphore(s) for circular buffer from syslogd");
-
 	// Suppose atomic memory move
-	i = follow ? buf->tail : buf->head;
+	cur = follow ? buf->tail : buf->head;
 
 	do {
 #ifdef CONFIG_FEATURE_LOGREAD_REDUCED_LOCKING
 		char *buf_data;
-		int log_len,j;
+		int log_len, j;
 #endif
-
 		sem_down(log_semid);
 
-		//printf("head: %i tail: %i size: %i\n",buf->head,buf->tail,buf->size);
+		if (DEBUG)
-		if (buf->head == buf->tail || i==buf->tail) {
+			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 */
@@ -114,58 +123,39 @@ int logread_main(int argc, char **argv)
 
 		// Read Memory
 #ifdef CONFIG_FEATURE_LOGREAD_REDUCED_LOCKING
-		log_len = buf->tail - i;
+		log_len = buf->tail - cur;
 		if (log_len < 0)
 			log_len += buf->size;
 		buf_data = xmalloc(log_len);
 
-		if (buf->tail < i) {
+		if (buf->tail >= cur) {
-			memcpy(buf_data, buf->data+i, buf->size-i);
+			memcpy(buf_data, buf->data + cur, log_len);
-			memcpy(buf_data+buf->size-i, buf->data, buf->tail);
 		} else {
-			memcpy(buf_data, buf->data+i, buf->tail-i);
+			memcpy(buf_data, buf->data + cur, buf->size - cur);
+			memcpy(buf_data + buf->size - cur, buf->data, buf->tail);
 		}
-		i = buf->tail;
+		cur = buf->tail;
-
 #else
-		while ( i != buf->tail) {
+		while (cur != buf->tail) {
-			printf("%s", buf->data+i);
+			fputs(buf->data + cur, stdout);
-			i+= strlen(buf->data+i) + 1;
+			cur += strlen(buf->data + cur) + 1;
-			if (i >= buf->size )
+			if (cur >= buf->size)
-				i=0;
+				cur = 0;
 		}
 #endif
 		// release the lock on the log chain
 		sem_up(log_semid);
 
 #ifdef CONFIG_FEATURE_LOGREAD_REDUCED_LOCKING
-		for (j=0; j < log_len; j+=strlen(buf_data+j)+1) {
+		for (j = 0; j < log_len; j += strlen(buf_data+j) + 1) {
-			printf("%s", buf_data+j);
+			fputs(buf_data + j, stdout);
-			if (follow)
-				fflush(stdout);
 		}
 		free(buf_data);
 #endif
 		fflush(stdout);
 	} while (follow);
 
-output_end:
+	shmdt(buf);
-	if (log_shmid != -1)
-		shmdt(buf);
 
 	return EXIT_SUCCESS;
 }
-
-static void interrupted(int sig){
-	signal(SIGINT, SIG_IGN);
-	longjmp(jmp_env, 1);
-}
-
-static void error_exit(const char *str){
-	bb_perror_msg(str);
-	//release all acquired resources
-	if (log_shmid != -1)
-		shmdt(buf);
-
-	exit(1);
-}

sysklogd/syslogd.c

@@ -22,19 +22,14 @@
 #include <sys/syslog.h>
 #include <sys/uio.h>
 
+#define DEBUG 0
+
 /* Path to the unix socket */
-static char dev_log_name[MAXPATHLEN];
+static char *dev_log_name;
 
 /* Path for the file where all log messages are written */
 static const char *logFilePath = "/var/log/messages";
 
-#if ENABLE_FEATURE_ROTATE_LOGFILE
-/* max size of message file before being rotated */
-static int logFileSize = 200 * 1024;
-/* number of rotated message files */
-static int logFileRotate = 1;
-#endif
-
 /* interval between marks in seconds */
 static int markInterval = 20 * 60;
 
@@ -44,6 +39,13 @@ static int logLevel = 8;
 /* localhost's name */
 static char localHostName[64];
 
+#if ENABLE_FEATURE_ROTATE_LOGFILE
+/* max size of message file before being rotated */
+static int logFileSize = 200 * 1024;
+/* number of rotated message files */
+static int logFileRotate = 1;
+#endif
+
 #if ENABLE_FEATURE_REMOTE_LOG
 #include <netinet/in.h>
 /* udp socket for logging to remote host */
@@ -142,6 +144,9 @@ static void ipcsyslog_cleanup(void)
 
 static void ipcsyslog_init(void)
 {
+	if (DEBUG)
+		printf("shmget(%lx, %d,...)\n", KEY_ID, shm_size);
+
 	shmid = shmget(KEY_ID, shm_size, IPC_CREAT | 1023);
 	if (shmid == -1) {
 		bb_perror_msg_and_die("shmget");
@@ -236,6 +241,8 @@ static void log_to_shmem(const char *msg, int len)
 	if (semop(s_semid, SMwup, 1) == -1) {
 		bb_perror_msg_and_die("SMwup");
 	}
+	if (DEBUG)
+		printf("head:%d tail:%d\n", shbuf->head, shbuf->tail);
 }
 #else
 void ipcsyslog_cleanup(void);
@@ -450,10 +457,12 @@ static void do_syslogd(void)
 	signal(SIGALRM, do_mark);
 	alarm(markInterval);
 
+	dev_log_name = xmalloc_realpath(_PATH_LOG);
+	if (!dev_log_name)
+		dev_log_name = _PATH_LOG;
+
 	/* Unlink old /dev/log (or object it points to) */
-	if (realpath(_PATH_LOG, dev_log_name) != NULL) {
+	unlink(dev_log_name);
-		unlink(dev_log_name);
-	}
 
 	memset(&sunx, 0, sizeof(sunx));
 	sunx.sun_family = AF_UNIX;
@@ -520,6 +529,7 @@ int syslogd_main(int argc, char **argv)
 	char *p;
 
 	/* do normal option parsing */
+	opt_complementary = "=0"; /* no non-option params */
 	getopt32(argc, argv, OPTION_STR, OPTION_PARAM);
 	if (option_mask32 & OPT_mark) // -m
 		markInterval = xatou_range(opt_m, 0, INT_MAX/60) * 60;