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-rw-r--r--coreutils/Config.in12
-rw-r--r--coreutils/dd.c33
2 files changed, 37 insertions, 8 deletions
diff --git a/coreutils/Config.in b/coreutils/Config.in
index 4eb3db0..6841ec9 100644
--- a/coreutils/Config.in
+++ b/coreutils/Config.in
@@ -115,6 +115,18 @@ config CONFIG_DD
by default) using specific input and output blocksizes,
while optionally performing conversions on it.
+config CONFIG_FEATURE_DD_SIGNAL_HANDLING
+ bool "Enable DD signal handling for status reporting"
+ default y
+ depends on CONFIG_DD
+ help
+ sending a SIGUSR1 signal to a running `dd' process makes it
+ print to standard error the number of records read and written
+ so far, then to resume copying.
+
+ $ dd if=/dev/zero of=/dev/null& pid=$! $ kill -USR1 $pid; sleep 1; kill $pid
+ 10899206+0 records in 10899206+0 records out
+
config CONFIG_DF
bool "df"
default n
diff --git a/coreutils/dd.c b/coreutils/dd.c
index ce8bcc6..378e212 100644
--- a/coreutils/dd.c
+++ b/coreutils/dd.c
@@ -15,9 +15,9 @@
#include <unistd.h>
#include <string.h>
#include <fcntl.h>
+#include <signal.h> // For FEATURE_DD_SIGNAL_HANDLING
#include "busybox.h"
-
static const struct suffix_mult dd_suffixes[] = {
{ "c", 1 },
{ "w", 2 },
@@ -31,12 +31,20 @@ static const struct suffix_mult dd_suffixes[] = {
{ NULL, 0 }
};
+static size_t out_full;
+static size_t out_part;
+static size_t in_full;
+static size_t in_part;
+
+static void dd_output_status(int cur_signal)
+{
+ fprintf(stderr, "%ld+%ld records in\n%ld+%ld records out\n",
+ (long)in_full, (long)in_part,
+ (long)out_full, (long)out_part);
+}
+
int dd_main(int argc, char **argv)
{
- size_t out_full = 0;
- size_t out_part = 0;
- size_t in_full = 0;
- size_t in_part = 0;
size_t count = -1;
size_t bs = 512;
ssize_t n;
@@ -53,6 +61,17 @@ int dd_main(int argc, char **argv)
const char *outfile = NULL;
char *buf;
+ if (ENABLE_FEATURE_DD_SIGNAL_HANDLING)
+ {
+ struct sigaction sa;
+
+ memset(&sa, 0, sizeof(sa));
+ sa.sa_handler = dd_output_status;
+ sa.sa_flags = SA_RESTART;
+ sigemptyset(&sa.sa_mask);
+ sigaction(SIGUSR1, &sa, 0);
+ }
+
for (i = 1; i < argc; i++) {
if (strncmp("bs=", argv[i], 3) == 0)
bs = bb_xparse_number(argv[i]+3, dd_suffixes);
@@ -180,9 +199,7 @@ int dd_main(int argc, char **argv)
bb_perror_msg_and_die("%s", outfile);
}
- fprintf(stderr, "%ld+%ld records in\n%ld+%ld records out\n",
- (long)in_full, (long)in_part,
- (long)out_full, (long)out_part);
+ dd_output_status(0);
return EXIT_SUCCESS;
}