From 02442af0aec2d75aaab73cd605519eddfbe07a29 Mon Sep 17 00:00:00 2001
From: Luke Shumaker <lukeshu@beefcake.parabola.nu>
Date: Fri, 18 May 2018 13:08:11 -0400
Subject: cow-extent-map: allow multiple files, machine output

---
 src/cow-extent-map.c | 50 +++++++++++++++++++++++++++++++++++++++++---------
 1 file changed, 41 insertions(+), 9 deletions(-)

diff --git a/src/cow-extent-map.c b/src/cow-extent-map.c
index aeedadf..6e7ee57 100644
--- a/src/cow-extent-map.c
+++ b/src/cow-extent-map.c
@@ -5,6 +5,7 @@
 #include <fcntl.h>    /* for open(2) and O_RDONLY */
 #include <getopt.h>   /* for getopt_long(3gnu), struct option, optind, optarg */
 #include <inttypes.h> /* PRI* */
+#include <stdbool.h>  /* for bool, true, false */
 #include <stdio.h>    /* for printf(3p), fprintf(3p), stderr */
 #include <stdlib.h>   /* free(3p), exit(3p), EXIT_SUCCESS, EXIT_FAILURE */
 #include <string.h>   /* for strcmp(3p) */
@@ -18,12 +19,16 @@
 	exit(EXIT_INVALIDARGUMENT); \
 } while(0)
 
+bool indent;
+
 int print_extent(struct fiemap_extent extent) {
 	char *flagstr = strextentflags(extent.fe_flags);
-	printf("logical=%"PRIu64" "
+	printf("%s"
+	       "logical=%"PRIu64" "
 	       "physical=%"PRIu64" "
 	       "length=%"PRIu64" "
 	       "flags=0x%08"PRIx32" (%s)\n",
+	       indent ? "\t" : "",
 	       extent.fe_logical,
 	       extent.fe_physical,
 	       extent.fe_length,
@@ -34,7 +39,7 @@ int print_extent(struct fiemap_extent extent) {
 }
 
 void usage() {
-	printf("Usage: %s [OPTIONS] FILENAME\n"
+	printf("Usage: %s [OPTIONS] FILENAME...\n"
 	       "Print a file extent map.\n"
 	       "\n"
 	       "OPTIONS:\n"
@@ -42,12 +47,14 @@ void usage() {
 	       "  --stream=xattr  Map extents in the extended attribute stream.\n"
 	       "  --sync          Sync the file before mapping extents (default).\n"
 	       "  --no-sync       Don't sync the file before mapping extents.\n"
+	       "  -m, --machine   Display the output in a more machine-friendly format.\n"
 	       "  -h, --help      Display this help and exit.\n",
 	       program_invocation_name);
 }
 
 int main(int argc, char *argv[]) {
 	char *stream = "data";
+	bool machine = false;
 	int sync = 1;
 	struct option long_options[] = {
 		{"stream",  optional_argument, NULL, 1},
@@ -57,13 +64,16 @@ int main(int argc, char *argv[]) {
 		{0},
 	};
 	int flag;
-	while ((flag = getopt_long(argc, argv, "h", long_options, NULL)) >= 0) {
+	while ((flag = getopt_long(argc, argv, "mh", long_options, NULL)) >= 0) {
 		switch (flag) {
 		case 0:
 			break;
 		case 1:
 			stream = optarg;
 			break;
+		case 'm':
+			machine = true;
+			break;
 		case 'h':
 			usage();
 			return EXIT_SUCCESS;
@@ -74,7 +84,7 @@ int main(int argc, char *argv[]) {
 			assert(0);
 		}
 	}
-	if (argc - optind != 1)
+	if (argc - optind < 1)
 		errusage("wrong number of arguments");
 
 	uint32_t flags = sync ? FIEMAP_FLAG_SYNC : 0;
@@ -86,10 +96,32 @@ int main(int argc, char *argv[]) {
 		errusage("invalid stream name");
 	}
 
-	char *filename = argv[optind];
-	int fd = open(filename, O_RDONLY);
-	if (fd < 0)
-		error(EXIT_FAILURE, errno, "%s", filename);
+	indent = (argc - optind) > 1 && !machine;
+
+	int status = 0;
+	for (int i = optind; i < argc; i++) {
+		char *filename = argv[i];
+		if (machine) {
+			printf("%s", filename);
+			putchar('\0');
+		} else if (argc - optind > 1)
+			printf("%s:\n", filename);
+		int fd = open(filename, O_RDONLY);
+		if (fd < 0) {
+			error(0, errno, "%s", filename);
+			status |= EXIT_FAILURE;
+			continue;
+		}
 
-	return fiemap(fd, flags, print_extent);
+		int r = fiemap(fd, flags, print_extent);
+		if (r < 0) {
+			error(0, -r, "%s: FS_IOC_FIEMAP", filename);
+			status |= EXIT_FAILURE;
+		} else {
+			status |= r;
+		}
+		if (machine)
+			putchar('\0');
+	}
+	return status;
 }
-- 
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