time: implement %% and \escapes in -f FMT

function                                             old     new   delta
time_main                                           1217    1316     +99

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

2 files changed, 55 insertions, 21 deletions

diff --git a/miscutils/time.c b/miscutils/time.c
index 4b1b043c3..77d35a832 100644
--- a/miscutils/time.c
+++ b/miscutils/time.c
@@ -226,28 +226,19 @@ static void summarize(const char *fmt, char **command, resource_t *resp)
                 }
 
                 switch (*fmt) {
-#ifdef NOT_NEEDED
-                /* Handle literal char */
-                /* Usually we optimize for size, but there is a limit
-                 * for everything. With this we do a lot of 1-byte writes */
-                default:
-                        bb_putchar(*fmt);
-                        break;
-#endif
-
                 case '%':
                         switch (*++fmt) {
-#ifdef NOT_NEEDED_YET
-                /* Our format strings do not have these */
-                /* and we do not take format str from user */
                         default:
-                                bb_putchar('%');
+                                /* Unknown %<char> is printed as "?<char>" */
+                                bb_putchar('?');
+                                if (!*fmt) {
+                                        /* Trailing -f '...%' prints "...?" but NOT newline */
+                                        goto ret;
+                                }
                                 /*FALLTHROUGH*/
                         case '%':
-                                if (!*fmt) goto ret;
                                 bb_putchar(*fmt);
                                 break;
-#endif
                         case 'C':       /* The command that got timed.  */
                                 printargv(command);
                                 break;
@@ -381,14 +372,21 @@ static void summarize(const char *fmt, char **command, resource_t *resp)
                         }
                         break;
 
-#ifdef NOT_NEEDED_YET
-                case '\\':              /* Format escape.  */
+                default: /* *fmt is '\': format escape */
                         switch (*++fmt) {
                         default:
+                                /* Unknown \<char> is printed as "?\<char>" */
+                                bb_putchar('?');
                                 bb_putchar('\\');
+                                if (!*fmt) {
+                                        /* Trailing -f '...\': GNU time 1.9 prints
+                                         * "...?\COMMAND" (it's probably a bug).
+                                         */
+                                        puts(command[0]);
+                                        goto ret;
+                                }
                                 /*FALLTHROUGH*/
                         case '\\':
-                                if (!*fmt) goto ret;
                                 bb_putchar(*fmt);
                                 break;
                         case 't':
@@ -399,12 +397,11 @@ static void summarize(const char *fmt, char **command, resource_t *resp)
                                 break;
                         }
                         break;
-#endif
                 }
                 ++fmt;
         }
- /* ret: */
         bb_putchar('\n');
+ ret: ;
 }
 
 /* Run command CMD and return statistics on it.
@@ -438,7 +435,7 @@ int time_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int time_main(int argc UNUSED_PARAM, char **argv)
 {
         resource_t res;
-        /* $TIME has lowest prio (-v,-p,-f FMT overrride it) */
+        /* $TIME has lowest prio (-v,-p,-f FMT override it) */
         const char *output_format = getenv("TIME") ? : default_format;
         char *output_filename;
         int output_fd;
diff --git a/testsuite/time.tests b/testsuite/time.tests
new file mode 100755
index 000000000..4e31b3868
--- /dev/null
+++ b/testsuite/time.tests
@@ -0,0 +1,37 @@
+#!/bin/sh
+
+# Copyright 2024 by Denys Vlasenko <vda.linux@googlemail.com>
+# Licensed under GPLv2, see file LICENSE in this source tree.
+
+. ./testing.sh
+
+# testing "description" "arguments" "result" "infile" "stdin"
+
+testing "time -f trailing backslash" \
+        "time -f 'abc\' sleep 0 2>&1" \
+        'abc?\sleep\n' '' ''
+#       ^^^^^^^^^^^^^^ this is what GNU time version 1.9 prints
+
+testing "time -f trailing percent" \
+        "time -f 'abc%' sleep 0 2>&1" \
+        'abc?' '' ''
+
+testing "time -f undefined backslash" \
+        "time -f 'abc\^def' sleep 0 2>&1" \
+        'abc?\^def\n' '' ''
+
+testing "time -f undefined percent" \
+        "time -f 'abc%^def' sleep 0 2>&1" \
+        'abc?^def\n' '' ''
+
+testing "time -f backslash tab and newline" \
+        "time -f 'abc\ndef\txyz' sleep 0 2>&1" \
+        'abc
+def     xyz
+' '' ''
+
+testing "time -f percent percent" \
+        "time -f 'abc%%def' sleep 0 2>&1" \
+        'abc%def\n' '' ''
+
+exit $FAILCOUNT