Add logsave, a new program which saves the output of a command

in a log file, even if the containing directory hasn't been
mounted yet (in which case the it saves the output in
memory until it can write out the logfile).

e2fsprogs.spec.in

@@ -99,6 +99,7 @@ fi
 %{_root_sbindir}/fsck
 %{_root_sbindir}/fsck.ext2
 %{_root_sbindir}/fsck.ext3
+%{_root_sbindir}/logsave
 %{_root_sbindir}/mke2fs
 %{_root_sbindir}/mkfs.ext2
 %{_root_sbindir}/mkfs.ext3
@@ -131,6 +132,7 @@ fi
 %{_mandir}/man8/e2image.8*
 %{_mandir}/man8/e2label.8*
 %{_mandir}/man8/fsck.8*
+%{_mandir}/man8/logsave.8*
 %{_mandir}/man8/mke2fs.8*
 %{_mandir}/man8/mkfs.ext2.8*
 %{_mandir}/man8/mkfs.ext3.8*

misc/ChangeLog

+2003-04-14  Theodore Ts'o  <tytso@mit.edu>
+
+	* logsave.c: New program which saves the output of a command in a
+		log file, even if the containing directory hasn't been
+		mounted yet (in which case the it saves the output in
+		memory until it can write out the logfile).
+
 2003-04-11  Theodore Ts'o  <tytso@mit.edu>
 
 	* mke2fs.c (PRS): If the argument to -b is negative, treat it as a

misc/Makefile.in

@@ -14,10 +14,12 @@ INSTALL = @INSTALL@
 @IMAGER_CMT@E2IMAGE_PROG= e2image
 @IMAGER_CMT@E2IMAGE_MAN= e2image.8
 
-SPROGS=		mke2fs badblocks tune2fs dumpe2fs blkid $(E2IMAGE_PROG) @FSCK_PROG@
+SPROGS=		mke2fs badblocks tune2fs dumpe2fs blkid logsave \
+			$(E2IMAGE_PROG) @FSCK_PROG@ 
 USPROGS=	mklost+found
 SMANPAGES=	tune2fs.8 mklost+found.8 mke2fs.8 dumpe2fs.8 badblocks.8 \
-			e2label.8 findfs.8 blkid.8 $(E2IMAGE_MAN) @FSCK_MAN@
+			e2label.8 findfs.8 blkid.8 $(E2IMAGE_MAN) \
+			logsave.8 @FSCK_MAN@
 
 UPROGS=		chattr lsattr uuidgen
 UMANPAGES=	chattr.1 lsattr.1 uuidgen.1
@@ -109,6 +111,9 @@ fsck: $(FSCK_OBJS) $(DEBLIBS_BLKID)
 badblocks: $(BADBLOCKS_OBJS) $(DEPLIBS)
 	$(CC) $(ALL_LDFLAGS) -o badblocks $(BADBLOCKS_OBJS) $(LIBS)
 
+logsave: logsave.o
+	$(CC) $(ALL_LDFLAGS) -o logsave logsave.o
+
 tune2fs.8: $(DEP_SUBSTITUTE) $(srcdir)/tune2fs.8.in
 	$(SUBSTITUTE) $(srcdir)/tune2fs.8.in tune2fs.8
 
@@ -139,6 +144,9 @@ fsck.8: $(DEP_SUBSTITUTE) $(srcdir)/fsck.8.in
 blkid.8: $(DEP_SUBSTITUTE) $(srcdir)/blkid.8.in
 	$(SUBSTITUTE) $(srcdir)/blkid.8.in blkid.8
 
+logsave.8: $(DEP_SUBSTITUTE) $(srcdir)/logsave.8.in
+	$(SUBSTITUTE) $(srcdir)/logsave.8.in logsave.8
+
 chattr.1: $(DEP_SUBSTITUTE) $(srcdir)/chattr.1.in
 	$(SUBSTITUTE) $(srcdir)/chattr.1.in chattr.1 
 

misc/logsave.8.in

+.\" -*- nroff -*-
+.\" Copyright 2003 by Theodore Ts'o.  All Rights Reserved.
+.\" This file may be copied under the terms of the GNU Public License.
+.\" 
+.TH LOGSAVE 8 "@E2FSPROGS_MONTH@ @E2FSPROGS_YEAR@" "E2fsprogs version @E2FSPROGS_VERSION@"
+.SH NAME
+logsave \- save the output of a command in a logfile
+.SH SYNOPSIS
+.B logsave
+[
+.B \-v
+]
+.I logfile command [ ... ]
+.SH DESCRIPTION
+The
+.B logsave
+program will execute
+.I command 
+with the specified argument, and save a copy of its output to
+.IR logfile .
+If the containing directory for
+.I logfile
+does not exist, 
+.B logsave
+will accumulate the output in memory until it can be written out.
+A copy of the output will also be written to standard output.
+.PP
+If 
+.I command
+is a single hyphen ('-'), then instead of executing a program,
+.B logsave
+will take the input from standard input.
+.PP
+.B logsave
+is useful for saving the output of initial boot scripts 
+until the /var partition is mounted, so the output can be written to 
+/var/log.
+.SH OPTIONS
+.TP
+.B \-a
+This option will cause the output to be appended to 
+.IR logfile ,
+instead of replacing the current contents.
+.TP
+.B \-v
+This option will
+.B logsave
+more verbose.
+.SH AUTHOR
+Theodore Ts'o (tytso@mit.edu)
+.SH SEE ALSO
+.BR fsck (8)

misc/logsave.c

+/*
+ * logsave.c --- A program which saves the output of a program until
+ *	/var/log is mounted.
+ *
+ * Copyright (C) 2003 Theodore Ts'o.
+ *
+ * %Begin-Header%
+ * This file may be redistributed under the terms of the GNU Public
+ * License.
+ * %End-Header%
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <fcntl.h>
+#include <time.h>
+#include <errno.h>
+#ifdef HAVE_GETOPT_H
+#include <getopt.h>
+#else
+extern char *optarg;
+extern int optind;
+#endif
+
+int	outfd = -1;
+int	outbufsize = 0;
+void	*outbuf = 0;
+int	verbose = 0;
+
+static void usage(char *progname)
+{
+	printf("Usage: %s [-v] [-d dir] logfile program\n", progname);
+	exit(1);
+}
+
+static void process_output(const char *buffer, int c)
+{
+	char	*n;
+	
+	if (c == 0)
+		c = strlen(buffer);
+	
+	write(1, buffer, c);
+	if (outfd > 0)
+		write(outfd, buffer, c);
+	else {
+		n = realloc(outbuf, outbufsize + c);
+		if (n) {
+			outbuf = n;
+			memcpy(((char *)outbuf)+outbufsize, buffer, c);
+			outbufsize += c;
+		}
+	}
+}
+
+static void do_read(int fd)
+{
+	int	c;
+	char	buffer[4096];
+
+	c = read(fd, buffer, sizeof(buffer));
+	process_output(buffer, c);
+}
+
+static int run_program(char **argv)
+{
+	int	fds[2];
+	char	**cpp;
+	int	status, rc, pid;
+	char	buffer[80];
+	time_t	t;
+
+	if (pipe(fds) < 0) {
+		perror("pipe");
+		exit(1);
+	}
+
+	if (verbose) {
+		process_output("Log of ", 0);
+		for (cpp = argv; *cpp; cpp++) {
+			process_output(*cpp, 0);
+			process_output(" ", 0);
+		}
+		process_output("\n", 0);
+		t = time(0);
+		process_output(ctime(&t), 0);
+		process_output("\n", 0);
+	}
+	
+	pid = fork();
+	if (pid < 0) {
+		perror("vfork");
+		exit(1);
+	}
+	if (pid == 0) {
+		dup2(fds[1],1);		/* fds[1] replaces stdout */
+		dup2(fds[1],2);  	/* fds[1] replaces stderr */
+		close(fds[0]);	/* don't need this here */
+		
+		execvp(argv[0], argv);
+		perror(argv[0]);
+		exit(1);
+	}
+	close(fds[1]);
+
+	while (!(waitpid(pid, &status, WNOHANG ))) {
+		do_read(fds[0]);
+	}
+	do_read(fds[0]);
+	close(fds[0]);
+
+	if ( WIFEXITED(status) ) {
+		rc = WEXITSTATUS(status);
+		if (rc) {
+			process_output(argv[0], 0);
+			sprintf(buffer, " died with exit status %d", rc);
+			process_output(buffer, 0);
+		}
+	} else {
+		if (WIFSIGNALED(status)) {
+			process_output(argv[0], 0);
+			sprintf(buffer, "died with signal %d",
+				WTERMSIG(status));
+			process_output(buffer, 0);
+			rc = 1;
+		}
+		rc = 0;
+	}
+	return rc;
+}
+
+static int copy_from_stdin(void)
+{
+	char	buffer[4096];
+	int	c;
+	int	bad_read = 0;
+
+	while (1) {
+		c = read(0, buffer, sizeof(buffer));
+		if ((c == 0 ) ||
+		    ((c < 0) && ((errno == EAGAIN) || (errno == EINTR)))) {
+			if (bad_read++ > 3)
+				break;
+			continue;
+		}
+		if (c < 0) {
+			perror("read");
+			exit(1);
+		}
+		process_output(buffer, c);
+		bad_read = 0;
+	}
+	return 0;
+}	
+	
+
+
+int main(int argc, char **argv)
+{
+	int	c, pid, rc;
+	char	*outfn;
+	int	openflags = O_CREAT|O_WRONLY|O_TRUNC;
+	
+	while ((c = getopt(argc, argv, "+v")) != EOF) {
+		switch (c) {
+		case 'a':
+			openflags &= ~O_TRUNC;
+			openflags |= O_APPEND;
+			break;
+		case 'v':
+			verbose++;
+			break;
+		}
+	}
+	if (optind == argc || optind+1 == argc)
+		usage(argv[0]);
+	outfn = argv[optind];
+	optind++;
+	argv += optind;
+	argc -= optind;
+
+	outfd = open(outfn, O_CREAT|O_WRONLY|O_TRUNC, 0644);
+
+	if (strcmp(argv[0], "-"))
+		rc = run_program(argv);
+	else
+		rc = copy_from_stdin();
+	
+	if (outbuf) {
+		pid = fork();
+		if (pid < 0) {
+			perror("fork");
+			exit(1);
+		}
+		if (pid) {
+			if (verbose)
+				printf("Backgrounding to save %s later\n",
+				       outfn);
+			exit(rc);
+		}
+		while (outfd < 0) {
+			outfd = open(outfn, O_CREAT|O_WRONLY|O_TRUNC, 0644);
+			sleep(1);
+		} 
+		write(outfd, outbuf, outbufsize);
+		free(outbuf);
+	}
+	close(outfd);
+	
+	exit(rc);
+}