diff options
| -rw-r--r-- | shell/ash_remove_unnecessary_code_in_backquote_expansion.patch | 135 |
1 files changed, 135 insertions, 0 deletions
diff --git a/shell/ash_remove_unnecessary_code_in_backquote_expansion.patch b/shell/ash_remove_unnecessary_code_in_backquote_expansion.patch new file mode 100644 index 0000000..06067dd --- /dev/null +++ b/shell/ash_remove_unnecessary_code_in_backquote_expansion.patch @@ -0,0 +1,135 @@ +From: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx> +Date: Thu, 19 Apr 2018 18:16:12 +0800 + +> ash originally had support for omitting the fork when expanding a +> builtin in backquotes. dash has gradually been removing this support, +> most recently in commit 66b614e29038e31745c4a5d296f64f8d64f5c377 +> ("[EVAL] Remove unused EV_BACKCMD flag"). +> +> Some traces still remain, however. Remove: +> +> - the buf and nleft elements of the backcmd structure; +> - a misleading comment regarding handling of builtins. +> +> Signed-off-by: Ron Yorston <rmy@xxxxxxxxxxxx> + +Unfortunately we may need this at some point in the future due +to changes in POSIX. So let's keep it around for now until we +get things such as `jobs -p` to work. + +************************************* + +From: Ron Yorston <rmy@xxxxxxxxxxxx> +Date: Thu, 19 Apr 2018 17:18:47 +0100 + +>Unfortunately we may need this at some point in the future due +>to changes in POSIX. So let's keep it around for now until we +>get things such as `jobs -p` to work. + +As you wish. + +Something even more trivial I noticed later: the TRACE at the end of +expbackq incorrectly refers to the function as evalbackq. + +************************************* + +Date: Tue, 10 Apr 2018 13:23:35 +0100 +From: Ron Yorston <rmy@pobox.com> +To: busybox@busybox.net +Subject: [PATCH] ash: remove unnecessary code in backquote expansion + +Some traces remain of ash's ancient support for omitting the fork when +expanding a builtin command in backquotes. + +Remove: + +- the buf and nleft elements of the backcmd structure; +- a misleading comment regarding handling of builtins. + +I've submitted a similar patch to dash. + +Signed-off-by: Ron Yorston <rmy@pobox.com> +--- + shell/ash.c | 37 +++++++++---------------------------- + 1 file changed, 9 insertions(+), 28 deletions(-) + +diff --git a/shell/ash.c b/shell/ash.c +index 45c747dbc..6f1458722 100644 +--- a/shell/ash.c ++++ b/shell/ash.c +@@ -6356,15 +6356,12 @@ exptilde(char *startp, char *p, int flags) + } + + /* +- * Execute a command inside back quotes. If it's a builtin command, we +- * want to save its output in a block obtained from malloc. Otherwise +- * we fork off a subprocess and get the output of the command via a pipe. +- * Should be called with interrupts off. ++ * Execute a command inside back quotes. We fork off a subprocess and ++ * get the output of the command via a pipe. Should be called with ++ * interrupts off. + */ + struct backcmd { /* result of evalbackcmd */ + int fd; /* file descriptor to read from */ +- int nleft; /* number of chars in buffer */ +- char *buf; /* buffer */ + struct job *jp; /* job structure for command */ + }; + +@@ -6394,8 +6391,6 @@ evalbackcmd(union node *n, struct backcmd *result) + struct job *jp; + + result->fd = -1; +- result->buf = NULL; +- result->nleft = 0; + result->jp = NULL; + if (n == NULL) { + goto out; +@@ -6432,8 +6427,7 @@ evalbackcmd(union node *n, struct backcmd *result) + result->jp = jp; + + out: +- TRACE(("evalbackcmd done: fd=%d buf=0x%x nleft=%d jp=0x%x\n", +- result->fd, result->buf, result->nleft, result->jp)); ++ TRACE(("evalbackcmd done: fd=%d jp=0x%x\n", result->fd, result->jp)); + } + + /* +@@ -6445,7 +6439,6 @@ expbackq(union node *cmd, int flag) + struct backcmd in; + int i; + char buf[128]; +- char *p; + char *dest; + int startloc; + int syntax = flag & EXP_QUOTED ? DQSYNTAX : BASESYNTAX; +@@ -6457,24 +6450,12 @@ expbackq(union node *cmd, int flag) + evalbackcmd(cmd, &in); + popstackmark(&smark); + +- p = in.buf; +- i = in.nleft; +- if (i == 0) +- goto read; +- for (;;) { +- memtodest(p, i, syntax, flag & QUOTES_ESC); +- read: +- if (in.fd < 0) +- break; +- i = nonblock_immune_read(in.fd, buf, sizeof(buf)); +- TRACE(("expbackq: read returns %d\n", i)); +- if (i <= 0) +- break; +- p = buf; +- } +- +- free(in.buf); + if (in.fd >= 0) { ++ while ((i = nonblock_immune_read(in.fd, buf, sizeof(buf))) > 0) { ++ TRACE(("expbackq: read returns %d\n", i)); ++ memtodest(buf, i, syntax, flag & QUOTES_ESC); ++ } ++ + close(in.fd); + back_exitstatus = waitforjob(in.jp); + } |