sbase

commit 2e5f1281ed4c5f16b9510263ecd05a3755de052f
parent 36a0a6cd9201ff6e04f4040d0302c90ea3ee6c5d
Author: Michael Forney <mforney@mforney.org>
Date:   Fri,  8 Jul 2016 10:24:13 -0700

touch: Use special UTIME_NOW and UTIME_OMIT values

This allows users to touch files they have write access to, but aren't the
owner.

Also, remove utime.h include (not necessary since
4132561c1729df9440a6ae2566a0cccadcccf860), and make sure to check the return
value of localtime (potentially preventing a NULL pointer derefence).

Diffstat:
M
touch.c
 | 
24
++++++++++++++----------

1 file changed, 14 insertions(+), 10 deletions(-)
diff --git a/touch.c b/touch.c
@@ -7,14 +7,13 @@
 #include <string.h>
 #include <time.h>
 #include <unistd.h>
-#include <utime.h>
 
 #include "util.h"
 
 static int aflag;
 static int cflag;
 static int mflag;
-static struct timespec times[2];
+static struct timespec times[2] = {{.tv_nsec = UTIME_NOW}};
 
 static void
 touch(const char *file)
@@ -28,10 +27,6 @@ touch(const char *file)
 		if (cflag)
 			return;
 	} else {
-		if (!aflag)
-			times[0] = st.st_atim;
-		if (!mflag)
-			times[1] = st.st_mtim;
 		if (utimensat(AT_FDCWD, file, times, 0) < 0)
 			eprintf("utimensat %s:", file);
 		return;
@@ -45,14 +40,18 @@ touch(const char *file)
 }
 
 static time_t
-parsetime(char *str, time_t current)
+parsetime(char *str)
 {
+	time_t now;
 	struct tm *cur, t = { 0 };
 	int zulu = 0;
 	char *format;
 	size_t len = strlen(str);
 
-	cur = localtime(&current);
+	if ((now = time(NULL)) == -1)
+		eprintf("time:");
+	if (!(cur = localtime(&now)))
+		eprintf("localtime:");
 	t.tm_isdst = -1;
 
 	switch (len) {
@@ -116,7 +115,6 @@ main(int argc, char *argv[])
 {
 	struct stat st;
 	char *ref = NULL;
-	clock_gettime(CLOCK_REALTIME, &times[0]);
 
 	ARGBEGIN {
 	case 'a':
@@ -127,7 +125,8 @@ main(int argc, char *argv[])
 		break;
 	case 'd':
 	case 't':
-		times[0].tv_sec = parsetime(EARGF(usage()), times[0].tv_sec);
+		times[0].tv_sec = parsetime(EARGF(usage()));
+		times[0].tv_nsec = 0;
 		break;
 	case 'm':
 		mflag = 1;
@@ -141,6 +140,7 @@ main(int argc, char *argv[])
 		break;
 	case 'T':
 		times[0].tv_sec = estrtonum(EARGF(usage()), 0, LLONG_MAX);
+		times[0].tv_nsec = 0;
 		break;
 	default:
 		usage();
@@ -152,6 +152,10 @@ main(int argc, char *argv[])
 		aflag = mflag = 1;
 	if (!ref)
 		times[1] = times[0];
+	if (!aflag)
+		times[0].tv_nsec = UTIME_OMIT;
+	if (!mflag)
+		times[1].tv_nsec = UTIME_OMIT;
 
 	for (; *argv; argc--, argv++)
 		touch(*argv);