Add the touch command to toolbox.

I wrote this to test my fix to support utime(2) system calls in the
sdcard fuse filesystem for stingray, and decided to finish sprucing
it up and make it part of toolbox.  In an effort to keep it small,
it doesn't accept dates a la touch, but just a time_t value.

Change-Id: I5dd011cd2e34d0cc605d6f40e46b96a8c949f194

2 files changed, 88 insertions, 0 deletions

diff --git a/toolbox/Android.mk b/toolbox/Android.mk
index ff01172e..76542a63 100644
--- a/toolbox/Android.mk
+++ b/toolbox/Android.mk
@@ -54,6 +54,7 @@ TOOLS := \
 	vmstat \
 	nandread \
 	ionice \
+	touch \
 	lsof
 
 LOCAL_SRC_FILES:= \
diff --git a/toolbox/touch.c b/toolbox/touch.c
new file mode 100644
index 00000000..b8ab310d
--- /dev/null
+++ b/toolbox/touch.c
@@ -0,0 +1,87 @@
+#include <stdio.h>
+#include <string.h>
+#include <sys/types.h>
+#include <fcntl.h>
+#include <sys/stat.h>
+#include <stdlib.h>
+#include <fcntl.h>
+
+static void usage(void)
+{
+        fprintf(stderr, "touch: usage: touch [-alm] [-t time_t] <file>\n");
+        exit(1);
+}
+
+int touch_main(int argc, char *argv[])
+{
+        int i, fd, aflag = 0, mflag = 0, debug = 0, flags = 0;
+        struct timespec specified_time, times[2];
+        char *file = 0;
+
+        specified_time.tv_nsec = UTIME_NOW;
+
+        for (i = 1; i < argc; i++) {
+            if (argv[i][0] == '-') {
+                /* an option */
+                const char *arg = argv[i]+1;
+                while (arg[0]) {
+                    switch (arg[0]) {
+                    case 'a': aflag = 1; break;
+                    case 'm': mflag = 1; break;
+                    case 't':
+                        if ((i+1) >= argc)
+                            usage();
+                        specified_time.tv_sec = atol(argv[++i]);
+                        if (specified_time.tv_sec == 0) {
+                            fprintf(stderr, "touch: invalid time_t\n");
+                            exit(1);
+                        }
+                        specified_time.tv_nsec = 0;
+                        break;
+                    case 'l': flags |= AT_SYMLINK_NOFOLLOW; break;
+                    case 'd': debug = 1; break;
+                    default:
+                        usage();
+                    }
+                    arg++;
+                }
+            } else {
+                /* not an option, and only accept one filename */
+                if (i+1 != argc)
+                    usage();
+                file = argv[i];
+            }
+        }
+
+        if (! file) {
+            fprintf(stderr, "touch: no file specified\n");
+            exit(1);
+        }
+
+        if (access(file, F_OK))
+            if ((fd=creat(file, 0666)) != -1)
+                close(fd);
+
+        if ((mflag == 0) && (aflag == 0))
+            aflag = mflag = 1;
+
+        if (aflag)
+            times[0] = specified_time;
+        else
+            times[0].tv_nsec = UTIME_OMIT;
+
+        if (mflag)
+            times[1] = specified_time;
+        else
+            times[1].tv_nsec = UTIME_OMIT;
+
+        if (debug) {
+            fprintf(stderr, "file = %s\n", file);
+            fprintf(stderr, "times[0].tv_sec = %ld, times[0].tv_nsec = %ld\n", times[0].tv_sec, times[0].tv_nsec);
+            fprintf(stderr, "times[1].tv_sec = %ld, times[1].tv_nsec = %ld\n", times[1].tv_sec, times[1].tv_nsec);
+            fprintf(stderr, "flags = 0x%8.8x\n", flags);
+        }
+
+        return utimensat(AT_FDCWD, file, times, flags);
+}
+