Add a new `W' flag, that when used in conjunction with the `Z' flag or the

`J' flag means that newsyslog should wait for previously started compression
jobs to complete before starting a new one for this entry.  When it is used
along with the `G' flag, in the case when several logfiles match the pattern
and should be compressed, the newsyslog will compress logs one by one,
ensuring that only one compression job is running at a time.

This prevents newsyslog(8) from overloading system by starting several
compression jobs on big files simultaneously.

Sponsored by:	Porta Software Ltd
MFC after:	2 weeks

2 files changed, 38 insertions, 8 deletions

diff --git a/usr.sbin/newsyslog/newsyslog.8 b/usr.sbin/newsyslog/newsyslog.8
index 03f540b..ea24206 100644
--- a/usr.sbin/newsyslog/newsyslog.8
+++ b/usr.sbin/newsyslog/newsyslog.8
@@ -292,6 +292,7 @@ turned over should not be included.  The
 flag means nothing, but can be used as a placeholder when the
 .Ar path_to_pid_file
 field is specified.
+The
 .Ar G
 flag means that the specified
 .Ar logfile_name
@@ -302,6 +303,23 @@ options.
 See
 .Xr glob 3
 for details on syntax and matching rules.
+The
+.Ar W
+flag
+in conjunction with the
+.Ar Z
+flag or the
+.Ar J
+flag means that
+.Nm
+should wait for previously started compression jobs to complete before
+starting a new one for this entry.  When it is used along with the
+.Ar G
+flag, in the case when several logfiles match the pattern and should be
+compressed, the
+.Nm
+will compress logs one by one, ensuring that only one compression job
+is running at a time.
 .It Ar path_to_pid_file
 This optional field specifies
 the file name to read to find the daemon process id.  If this
diff --git a/usr.sbin/newsyslog/newsyslog.c b/usr.sbin/newsyslog/newsyslog.c
index cfc983b..d9894a4 100644
--- a/usr.sbin/newsyslog/newsyslog.c
+++ b/usr.sbin/newsyslog/newsyslog.c
@@ -70,6 +70,8 @@ static const char rcsid[] =
 				/*  status messages */
 #define	CE_TRIMAT  4		/* trim at a specific time */
 #define	CE_GLOB    16		/* name of the log is file name pattern */
+#define	CE_COMPACTWAIT 32	/* wait till compressing finishes before */
+				/* starting the next one */
 
 #define NONE -1
 
@@ -112,8 +114,8 @@ static void usage(void);
 static void dotrim(char *log, const char *pid_file, int numdays, int falgs,
 		int perm, int owner_uid, int group_gid, int sig);
 static int log_trim(char *log);
-static void compress_log(char *log);
-static void bzcompress_log(char *log);
+static void compress_log(char *log, int dowait);
+static void bzcompress_log(char *log, int dowait);
 static int sizefile(char *file);
 static int age_old_log(char *file);
 static pid_t get_pid(const char *pid_file);
@@ -473,6 +475,8 @@ parse_file(char **files)
 				working->flags |= CE_BINARY;
 			else if ((*q == 'G') || (*q == 'c'))
 				working->flags |= CE_GLOB;
+			else if ((*q == 'W') || (*q == 'w'))
+				working->flags |= CE_COMPACTWAIT;
 			else if (*q != '-')
 				errx(1, "illegal flag in config file -- %c",
 				    *q);
@@ -736,14 +740,18 @@ dotrim(char *log, const char *pid_file, int numdays, int flags, int perm,
 				(void) snprintf(file1, sizeof(file1), "%s/%s",
 				    dirpart, namepart);
 				if (flags & CE_COMPACT)
-					compress_log(file1);
+					compress_log(file1,
+					    flags & CE_COMPACTWAIT);
 				else if (flags & CE_BZCOMPACT)
-					bzcompress_log(file1);
+					bzcompress_log(file1,
+					    flags & CE_COMPACTWAIT);
 			} else {
 				if (flags & CE_COMPACT)
-					compress_log(log);
+					compress_log(log,
+					    flags & CE_COMPACTWAIT);
 				else if (flags & CE_BZCOMPACT)
-					bzcompress_log(log);
+					bzcompress_log(log,
+					    flags & CE_COMPACTWAIT);
 			}
 		}
 	}
@@ -766,11 +774,13 @@ log_trim(char *log)
 
 /* Fork of gzip to compress the old log file */
 static void
-compress_log(char *log)
+compress_log(char *log, int dowait)
 {
 	pid_t pid;
 	char tmp[MAXPATHLEN];
 
+	while (dowait && (wait(NULL) > 0 || errno == EINTR))
+		;
 	(void) snprintf(tmp, sizeof(tmp), "%s.0", log);
 	pid = fork();
 	if (pid < 0)
@@ -783,11 +793,13 @@ compress_log(char *log)
 
 /* Fork of bzip2 to compress the old log file */
 static void
-bzcompress_log(char *log)
+bzcompress_log(char *log, int dowait)
 {
 	pid_t pid;
 	char tmp[MAXPATHLEN];
 
+	while (dowait && (wait(NULL) > 0 || errno == EINTR))
+		;
 	snprintf(tmp, sizeof(tmp), "%s.0", log);
 	pid = fork();
 	if (pid < 0)