From: Steve Kay <stevekay@gmail.com>
Date: Sat, 8 May 2021 18:32:24 +0000 (-0400)
Subject: optional unit suffix on -C
X-Git-Url: https://git.tcpdump.org/tcpdump/commitdiff_plain/81e2588d2ba6290cc189923287f1c042275a0bc5

optional unit suffix on -C
---

diff --git a/tcpdump.1.in b/tcpdump.1.in
index 355216d6..a6c00307 100644
--- a/tcpdump.1.in
+++ b/tcpdump.1.in
@@ -265,8 +265,12 @@ savefile and open a new one.  Savefiles after the first savefile will
 have the name specified with the
 .B \-w
 flag, with a number after it, starting at 1 and continuing upward.
-The units of \fIfile_size\fP are millions of bytes (1,000,000 bytes,
+The default unit of \fIfile_size\fP is millions of bytes (1,000,000 bytes,
 not 1,048,576 bytes).
+.IP
+By adding a suffix of k, m or g to the value, the unit
+can be changed to 1,024 (KiB), 1,048,576 (MiB), or 1,073,741,824 (GiB)
+respectively.
 .TP
 .B \-d
 Dump the compiled packet-matching code in a human readable form to
diff --git a/tcpdump.c b/tcpdump.c
index 0bde6468..b9c02c1d 100644
--- a/tcpdump.c
+++ b/tcpdump.c
@@ -1482,6 +1482,7 @@ main(int argc, char **argv)
 	int yflag_dlt = -1;
 	const char *yflag_dlt_name = NULL;
 	int print = 0;
+	long Cflagmult = 1000000;
 
 	netdissect_options Ndo;
 	netdissect_options *ndo = &Ndo;
@@ -1558,6 +1559,18 @@ main(int argc, char **argv)
 
 		case 'C':
 			errno = 0;
+			if (optarg[strlen(optarg)-1] == 'k') {
+				Cflagmult = 1024;
+				optarg[strlen(optarg)-1] = '\0';
+			}
+			if (optarg[strlen(optarg)-1] == 'm') {
+				Cflagmult = 1024*1024;
+				optarg[strlen(optarg)-1] = '\0';
+			}
+			if (optarg[strlen(optarg)-1] == 'g') {
+				Cflagmult = 1024*1024*1024;
+				optarg[strlen(optarg)-1] = '\0';
+			}
 #ifdef HAVE_PCAP_DUMP_FTELL64
 			Cflag = strtoint64_t(optarg, &endp, 10);
 #else
@@ -1567,15 +1580,15 @@ main(int argc, char **argv)
 			    || Cflag <= 0)
 				error("invalid file size %s", optarg);
 			/*
-			 * Will multiplying it by 1000000 overflow?
+			 * Will multiplying it by multiplier overflow?
 			 */
 #ifdef HAVE_PCAP_DUMP_FTELL64
-			if (Cflag > INT64_T_CONSTANT(0x7fffffffffffffff) / 1000000)
+			if (Cflag > INT64_T_CONSTANT(0x7fffffffffffffff) / Cflagmult)
 #else
-			if (Cflag > LONG_MAX / 1000000)
+			if (Cflag > LONG_MAX / Cflagmult)
 #endif
 				error("file size %s is too large", optarg);
-			Cflag *= 1000000;
+			Cflag *= Cflagmult;
 			break;
 
 		case 'd':