Teach savecore(8) how to extract textdump(4) dumps.

Update savecore(8) man page to reflect textdump additions.

MFC after:	3 months

2 files changed, 171 insertions, 79 deletions

diff --git a/sbin/savecore/savecore.8 b/sbin/savecore/savecore.8
index 447e008..487506d 100644
--- a/sbin/savecore/savecore.8
+++ b/sbin/savecore/savecore.8
@@ -102,6 +102,12 @@ If it passes these checks, it saves the core image in
 .Ar directory Ns Pa /vmcore.#
 and information about the core in
 .Ar directory Ns Pa /info.#
+For kernel textdumps generated with the
+.Xr textdump 4
+facility, output will be stored in the
+.Xr tar 5
+format and named
+.Ar director Ns Pa /textdump.tar.#
 The ``#'' is the number from the first line of the file
 .Ar directory Ns Pa /bounds ,
 and it is incremented and stored back into the file each time
@@ -137,6 +143,8 @@ is meant to be called near the end of the initialization file
 .Sh SEE ALSO
 .Xr gzip 1 ,
 .Xr getbootfile 3 ,
+.Xr textdump 4 ,
+.Xr tar 4 ,
 .Xr dumpon 8 ,
 .Xr syslogd 8
 .Sh HISTORY
@@ -144,5 +152,8 @@ The
 .Nm
 utility appeared in
 .Bx 4.1 .
+.Pp
+Support for kernel textdumps appeared in
+.Fx 8.0 .
 .Sh BUGS
 The minfree code does not consider the effect of compression or sparse files.
diff --git a/sbin/savecore/savecore.c b/sbin/savecore/savecore.c
index 88a6301..72448a3 100644
--- a/sbin/savecore/savecore.c
+++ b/sbin/savecore/savecore.c
@@ -226,21 +226,155 @@ check_space(const char *savedir, off_t dumpsize)
 #define BLOCKSIZE (1<<12)
 #define BLOCKMASK (~(BLOCKSIZE-1))
 
+static int
+DoRegularFile(int fd, off_t dumpsize, char *buf, const char *device,
+    const char *filename, FILE *fp)
+{
+	int he, hs, nr, nw, wl;
+	off_t dmpcnt;
+
+	dmpcnt = 0;
+	he = 0;
+	while (dumpsize > 0) {
+		wl = BUFFERSIZE;
+		if (wl > dumpsize)
+			wl = dumpsize;
+		nr = read(fd, buf, wl);
+		if (nr != wl) {
+			if (nr == 0)
+				syslog(LOG_WARNING,
+				    "WARNING: EOF on dump device");
+			else
+				syslog(LOG_ERR, "read error on %s: %m", device);
+			nerr++;
+			return (-1);
+		}
+		if (compress) {
+			nw = fwrite(buf, 1, wl, fp);
+		} else {
+			for (nw = 0; nw < nr; nw = he) {
+				/* find a contiguous block of zeroes */
+				for (hs = nw; hs < nr; hs += BLOCKSIZE) {
+					for (he = hs; he < nr && buf[he] == 0;
+					    ++he)
+						/* nothing */ ;
+					/* is the hole long enough to matter? */
+					if (he >= hs + BLOCKSIZE)
+						break;
+				}
+			
+				/* back down to a block boundary */
+				he &= BLOCKMASK;
+
+				/*
+				 * 1) Don't go beyond the end of the buffer.
+				 * 2) If the end of the buffer is less than
+				 *    BLOCKSIZE bytes away, we're at the end
+				 *    of the file, so just grab what's left.
+				 */
+				if (hs + BLOCKSIZE > nr)
+					hs = he = nr;
+
+				/*
+				 * At this point, we have a partial ordering:
+				 *     nw <= hs <= he <= nr
+				 * If hs > nw, buf[nw..hs] contains non-zero data.
+				 * If he > hs, buf[hs..he] is all zeroes.
+				 */
+				if (hs > nw)
+					if (fwrite(buf + nw, hs - nw, 1, fp)
+					    != 1)
+					break;
+				if (he > hs)
+					if (fseeko(fp, he - hs, SEEK_CUR) == -1)
+						break;
+			}
+		}
+		if (nw != wl) {
+			syslog(LOG_ERR,
+			    "write error on %s file: %m", filename);
+			syslog(LOG_WARNING,
+			    "WARNING: vmcore may be incomplete");
+			nerr++;
+			return (-1);
+		}
+		if (verbose) {
+			dmpcnt += wl;
+			printf("%llu\r", (unsigned long long)dmpcnt);
+			fflush(stdout);
+		}
+		dumpsize -= wl;
+	}
+	return (0);
+}
+
+/*
+ * Specialized version of dump-reading logic for use with textdumps, which
+ * are written backwards from the end of the partition, and must be reversed
+ * before being written to the file.  Textdumps are small, so do a bit less
+ * work to optimize/sparsify.
+ */
+static int
+DoTextdumpFile(int fd, off_t dumpsize, off_t lasthd, char *buf,
+    const char *device, const char *filename, FILE *fp)
+{
+	int nr, nw, wl;
+	off_t dmpcnt, totsize;
+
+	totsize = dumpsize;
+	dmpcnt = 0;
+	wl = 512;
+	if ((dumpsize % wl) != 0) {
+		syslog(LOG_ERR, "textdump uneven multiple of 512 on %s",
+		    device);
+		nerr++;
+		return (-1);
+	}
+	while (dumpsize > 0) {
+		nr = pread(fd, buf, wl, lasthd - (totsize - dumpsize) - wl);
+		if (nr != wl) {
+			if (nr == 0)
+				syslog(LOG_WARNING,
+				    "WARNING: EOF on dump device");
+			else
+				syslog(LOG_ERR, "read error on %s: %m", device);
+			nerr++;
+			return (-1);
+		}
+		nw = fwrite(buf, 1, wl, fp);
+		if (nw != wl) {
+			syslog(LOG_ERR,
+			    "write error on %s file: %m", filename);
+			syslog(LOG_WARNING,
+			    "WARNING: textdump may be incomplete");
+			nerr++;
+			return (-1);
+		}
+		if (verbose) {
+			dmpcnt += wl;
+			printf("%llu\r", (unsigned long long)dmpcnt);
+			fflush(stdout);
+		}
+		dumpsize -= wl;
+	}
+	return (0);
+}
+
 static void
 DoFile(const char *savedir, const char *device)
 {
+	static char filename[PATH_MAX];
 	static char *buf = NULL;
 	struct kerneldumpheader kdhf, kdhl;
-	off_t mediasize, dumpsize, firsthd, lasthd, dmpcnt;
+	off_t mediasize, dumpsize, firsthd, lasthd;
 	FILE *info, *fp;
 	mode_t oumask;
-	int fd, fdinfo, error, wl;
-	int nr, nw, hs, he = 0;
+	int fd, fdinfo, error;
 	int bounds, status;
 	u_int sectorsize;
+	int istextdump;
 
 	bounds = getbounds();
-	dmpcnt = 0;
 	mediasize = 0;
 	status = STATUS_UNKNOWN;
 
@@ -284,7 +418,13 @@ DoFile(const char *savedir, const char *device)
 		    (long long)lasthd, device);
 		goto closefd;
 	}
-	if (memcmp(kdhl.magic, KERNELDUMPMAGIC, sizeof kdhl.magic)) {
+	istextdump = 0;
+	if (memcmp(kdhl.magic, TEXTDUMPMAGIC, sizeof kdhl.magic)) {
+		if (verbose)
+			printf("textdump magic on last dump header on %s\n",
+			    device);
+		istextdump = 1;
+	} else if (memcmp(kdhl.magic, KERNELDUMPMAGIC, sizeof kdhl.magic)) {
 		if (verbose)
 			printf("magic mismatch on last dump header on %s\n",
 			    device);
@@ -391,14 +531,16 @@ DoFile(const char *savedir, const char *device)
 	}
 	oumask = umask(S_IRWXG|S_IRWXO); /* Restrict access to the core file.*/
 	if (compress) {
-		sprintf(buf, "vmcore.%d.gz", bounds);
-		fp = zopen(buf, "w");
+		sprintf(filename, "%s.%d.gz", istextdump ? "textdump.tar" :
+		    "vmcore", bounds);
+		fp = zopen(filename, "w");
 	} else {
-		sprintf(buf, "vmcore.%d", bounds);
-		fp = fopen(buf, "w");
+		sprintf(filename, "%s.%d", istextdump ? "textdump.tar" :
+		    "vmcore", bounds);
+		fp = fopen(filename, "w");
 	}
 	if (fp == NULL) {
-		syslog(LOG_ERR, "%s: %m", buf);
+		syslog(LOG_ERR, "%s: %m", filename);
 		close(fdinfo);
 		nerr++;
 		goto closefd;
@@ -420,83 +562,22 @@ DoFile(const char *savedir, const char *device)
 	fclose(info);
 
 	syslog(LOG_NOTICE, "writing %score to %s",
-	    compress ? "compressed " : "", buf);
+	    compress ? "compressed " : "", filename);
 
-	while (dumpsize > 0) {
-		wl = BUFFERSIZE;
-		if (wl > dumpsize)
-			wl = dumpsize;
-		nr = read(fd, buf, wl);
-		if (nr != wl) {
-			if (nr == 0)
-				syslog(LOG_WARNING,
-				    "WARNING: EOF on dump device");
-			else
-				syslog(LOG_ERR, "read error on %s: %m", device);
-			nerr++;
+	if (istextdump) {
+		if (DoTextdumpFile(fd, dumpsize, lasthd, buf, device,
+		    filename, fp) < 0)
 			goto closeall;
-		}
-		if (compress) {
-			nw = fwrite(buf, 1, wl, fp);
-		} else {
-			for (nw = 0; nw < nr; nw = he) {
-				/* find a contiguous block of zeroes */
-				for (hs = nw; hs < nr; hs += BLOCKSIZE) {
-					for (he = hs; he < nr && buf[he] == 0;
-					    ++he)
-						/* nothing */ ;
-					/* is the hole long enough to matter? */
-					if (he >= hs + BLOCKSIZE)
-						break;
-				}
-			
-				/* back down to a block boundary */
-				he &= BLOCKMASK;
-
-				/*
-				 * 1) Don't go beyond the end of the buffer.
-				 * 2) If the end of the buffer is less than
-				 *    BLOCKSIZE bytes away, we're at the end
-				 *    of the file, so just grab what's left.
-				 */
-				if (hs + BLOCKSIZE > nr)
-					hs = he = nr;
-
-				/*
-				 * At this point, we have a partial ordering:
-				 *     nw <= hs <= he <= nr
-				 * If hs > nw, buf[nw..hs] contains non-zero data.
-				 * If he > hs, buf[hs..he] is all zeroes.
-				 */
-				if (hs > nw)
-					if (fwrite(buf + nw, hs - nw, 1, fp)
-					    != 1)
-					break;
-				if (he > hs)
-					if (fseeko(fp, he - hs, SEEK_CUR) == -1)
-						break;
-			}
-		}
-		if (nw != wl) {
-			syslog(LOG_ERR,
-			    "write error on vmcore.%d file: %m", bounds);
-			syslog(LOG_WARNING,
-			    "WARNING: vmcore may be incomplete");
-			nerr++;
+	} else {
+		if (DoRegularFile(fd, dumpsize, buf, device, filename, fp)
+		    < 0)
 			goto closeall;
-		}
-		if (verbose) {
-			dmpcnt += wl;
-			printf("%llu\r", (unsigned long long)dmpcnt);
-			fflush(stdout);
-		}
-		dumpsize -= wl;
 	}
 	if (verbose)
 		printf("\n");
 
 	if (fclose(fp) < 0) {
-		syslog(LOG_ERR, "error on vmcore.%d: %m", bounds);
+		syslog(LOG_ERR, "error on %s: %m", filename);
 		nerr++;
 		goto closeall;
 	}