package/utils/busybox/501-ash-hush-fix-SIGCHLD-interrupting-read-builtin.patch

   1 From f5470419404d643070db99d058405b714695b817 Mon Sep 17 00:00:00 2001
   2 From: Denys Vlasenko <vda.linux@googlemail.com>
   3 Date: Mon, 22 May 2017 19:34:45 +0200
   4 Subject: [PATCH] ash,hush: fix SIGCHLD interrupting read builtin
   5
   6 function                                             old     new   delta
   7 readcmd                                              169     217     +48
   8 shell_builtin_read                                  1087    1097     +10
   9 localcmd                                             366     364      -2
  10 builtin_read                                         197     193      -4
  11 ------------------------------------------------------------------------------
  12 (add/remove: 0/0 grow/shrink: 2/2 up/down: 58/-6)              Total: 52 bytes
  13
  14 Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
  15 Signed-off-by: Bastian Bittorf <bb@npl.de>
  16 ---
  17  shell/ash.c                                  |  7 +++++++
  18  shell/ash_test/ash-read/read_SIGCHLD.right   |  2 ++
  19  shell/ash_test/ash-read/read_SIGCHLD.tests   |  4 ++++
  20  shell/hush.c                                 |  5 ++++-
  21  shell/hush_test/hush-read/read_SIGCHLD.right |  2 ++
  22  shell/hush_test/hush-read/read_SIGCHLD.tests |  4 ++++
  23  shell/shell_common.c                         | 20 +++++++++++---------
  24  7 files changed, 34 insertions(+), 10 deletions(-)
  25  create mode 100644 shell/ash_test/ash-read/read_SIGCHLD.right
  26  create mode 100755 shell/ash_test/ash-read/read_SIGCHLD.tests
  27  create mode 100644 shell/hush_test/hush-read/read_SIGCHLD.right
  28  create mode 100755 shell/hush_test/hush-read/read_SIGCHLD.tests
  29
  30 diff --git a/shell/ash.c b/shell/ash.c
  31 index 70ee15e..60c8ffe 100644
  32 --- a/shell/ash.c
  33 +++ b/shell/ash.c
  34 @@ -13268,6 +13268,7 @@ readcmd(int argc UNUSED_PARAM, char **argv UNUSED_PARAM)
  35         /* "read -s" needs to save/restore termios, can't allow ^C
  36          * to jump out of it.
  37          */
  38 + again:
  39         INT_OFF;
  40         r = shell_builtin_read(setvar0,
  41                 argptr,
  42 @@ -13280,6 +13281,12 @@ readcmd(int argc UNUSED_PARAM, char **argv UNUSED_PARAM)
  43         );
  44         INT_ON;
  45
  46 +       if ((uintptr_t)r == 1 && errno == EINTR) {
  47 +               /* to get SIGCHLD: sleep 1 & read x; echo $x */
  48 +               if (pending_sig == 0)
  49 +                       goto again;
  50 +       }
  51 +
  52         if ((uintptr_t)r > 1)
  53                 ash_msg_and_raise_error(r);
  54
  55 diff --git a/shell/ash_test/ash-read/read_SIGCHLD.right b/shell/ash_test/ash-read/read_SIGCHLD.right
  56 new file mode 100644
  57 index 0000000..b3dc7ab
  58 --- /dev/null
  59 +++ b/shell/ash_test/ash-read/read_SIGCHLD.right
  60 @@ -0,0 +1,2 @@
  61 +x='Ok'
  62 +exitcode:0
  63 diff --git a/shell/ash_test/ash-read/read_SIGCHLD.tests b/shell/ash_test/ash-read/read_SIGCHLD.tests
  64 new file mode 100755
  65 index 0000000..c5f673a
  66 --- /dev/null
  67 +++ b/shell/ash_test/ash-read/read_SIGCHLD.tests
  68 @@ -0,0 +1,4 @@
  69 +x=BAD
  70 +{ sleep 0.4; echo Ok; } | { sleep 0.2 & read x; echo "x='$x'"; }
  71 +echo "exitcode:$?"
  72 +
  73 diff --git a/shell/hush.c b/shell/hush.c
  74 index e18920f..125463a 100644
  75 --- a/shell/hush.c
  76 +++ b/shell/hush.c
  77 @@ -9038,6 +9038,9 @@ static int FAST_FUNC builtin_type(char **argv)
  78   * - terminates shell (regardless of interactivity);
  79   * if it has non-empty trap:
  80   * - executes trap and returns to read;
  81 + * SIGCHLD from children:
  82 + * - does not interrupt read regardless of interactivity:
  83 + *   try: sleep 1 & read x; echo $x
  84   */
  85  static int FAST_FUNC builtin_read(char **argv)
  86  {
  87 @@ -9071,7 +9074,7 @@ static int FAST_FUNC builtin_read(char **argv)
  88
  89         if ((uintptr_t)r == 1 && errno == EINTR) {
  90                 unsigned sig = check_and_run_traps();
  91 -               if (sig && sig != SIGINT)
  92 +               if (sig != SIGINT)
  93                         goto again;
  94         }
  95
  96 diff --git a/shell/hush_test/hush-read/read_SIGCHLD.right b/shell/hush_test/hush-read/read_SIGCHLD.right
  97 new file mode 100644
  98 index 0000000..b3dc7ab
  99 --- /dev/null
 100 +++ b/shell/hush_test/hush-read/read_SIGCHLD.right
 101 @@ -0,0 +1,2 @@
 102 +x='Ok'
 103 +exitcode:0
 104 diff --git a/shell/hush_test/hush-read/read_SIGCHLD.tests b/shell/hush_test/hush-read/read_SIGCHLD.tests
 105 new file mode 100755
 106 index 0000000..c5f673a
 107 --- /dev/null
 108 +++ b/shell/hush_test/hush-read/read_SIGCHLD.tests
 109 @@ -0,0 +1,4 @@
 110 +x=BAD
 111 +{ sleep 0.4; echo Ok; } | { sleep 0.2 & read x; echo "x='$x'"; }
 112 +echo "exitcode:$?"
 113 +
 114 diff --git a/shell/shell_common.c b/shell/shell_common.c
 115 index fb86e68..03b7d0b 100644
 116 --- a/shell/shell_common.c
 117 +++ b/shell/shell_common.c
 118 @@ -204,15 +204,17 @@ shell_builtin_read(void FAST_FUNC (*setvar)(const char *name, const char *val),
 119                 c = buffer[bufpos];
 120                 if (c == '\0')
 121                         continue;
 122 -               if (backslash) {
 123 -                       backslash = 0;
 124 -                       if (c != '\n')
 125 -                               goto put;
 126 -                       continue;
 127 -               }
 128 -               if (!(read_flags & BUILTIN_READ_RAW) && c == '\\') {
 129 -                       backslash = 1;
 130 -                       continue;
 131 +               if (!(read_flags & BUILTIN_READ_RAW)) {
 132 +                       if (backslash) {
 133 +                               backslash = 0;
 134 +                               if (c != '\n')
 135 +                                       goto put;
 136 +                               continue;
 137 +                       }
 138 +                       if (c == '\\') {
 139 +                               backslash = 1;
 140 +                               continue;
 141 +                       }
 142                 }
 143                 if (c == '\n')
 144                         break;
 145 --
 146 1.9.1
 147