From: Stephane Chazelas <stephane.chazelas@gmail.com>
To: Peter Stephenson <p.stephenson@samsung.com>
Cc: Zsh hackers list <zsh-workers@zsh.org>
Subject: Re: $(<nofile) doesn't set $? to non-zero
Date: Thu, 15 Mar 2018 07:12:04 +0000 [thread overview]
Message-ID: <20180315071204.GA10057@chaz.gmail.com> (raw)
In-Reply-To: <20180314145004.6e4b971b@camnpupstephen>
2018-03-14 14:50:04 +0000, Peter Stephenson:
> On Wed, 14 Mar 2018 14:42:48 +0000
> Stephane Chazelas <stephane.chazelas@gmail.com> wrote:
> > Would it be worth doing some:
> >
> > ret = readoutput(stream, qt);
> > if (errno) {
> > zwarn("%e: %s", errno, s);
> > lastval = cmdoutval = 1;
> > }
> > return ret;
> >
> > there (or something cleaner to avoid relying on errno)?
>
> The return value is the linked list as we're in the context of
> substitution, not command execution, which isn't easy to change without
> a complete rewrite.
[...]
Why not just pass the error as a return argument like in the
patch below?
Then:
$ ./Src/zsh -c 'ERRNO=0; v=$(</x); echo $? $ERRNO $#v'
zsh:1: no such file or directory: /x
1 2 0
$ ./Src/zsh -c 'ERRNO=0; v=$(</); echo $? $ERRNO $#v'
zsh:1: error when reading /: is a directory
1 21 0
$ ./Src/zsh -c 'ERRNO=0; v=$(</dev/mem); echo $? $ERRNO $#v'
zsh:1: permission denied: /dev/mem
1 13 0
$ sudo ./Src/zsh -c 'ERRNO=0; v=$(</dev/mem); echo $? $ERRNO $#v'
zsh:1: error when reading /dev/mem: operation not permitted
1 1 1046296
We still expand to what could be read but signal the error like
when doing the unoptimised $(cat file).
diff --git a/Src/Modules/mapfile.c b/Src/Modules/mapfile.c
index 2503b36..7c5a1e3 100644
--- a/Src/Modules/mapfile.c
+++ b/Src/Modules/mapfile.c
@@ -197,8 +197,9 @@ get_contents(char *fname)
val = NULL;
if ((fd = open(fname, O_RDONLY | O_NOCTTY)) >= 0) {
LinkList ll;
+ int readerror;
- if ((ll = readoutput(fd, 1)))
+ if ((ll = readoutput(fd, 1, 0)))
val = peekfirst(ll);
}
#endif /* USE_MMAP */
diff --git a/Src/exec.c b/Src/exec.c
index e5c6455..32be683 100644
--- a/Src/exec.c
+++ b/Src/exec.c
@@ -4507,6 +4507,8 @@ getoutput(char *cmd, int qt)
if ((s = simple_redir_name(prog, REDIR_READ))) {
/* $(< word) */
int stream;
+ LinkList retval;
+ int readerror;
singsub(&s);
if (errflag)
@@ -4514,9 +4516,15 @@ getoutput(char *cmd, int qt)
untokenize(s);
if ((stream = open(unmeta(s), O_RDONLY | O_NOCTTY)) == -1) {
zwarn("%e: %s", errno, s);
+ lastval = cmdoutval = 1;
return newlinklist();
}
- return readoutput(stream, qt);
+ retval = readoutput(stream, qt, &readerror);
+ if (readerror) {
+ zwarn("error when reading %s: %e", s, readerror);
+ lastval = cmdoutval = 1;
+ }
+ return retval;
}
if (mpipe(pipes) < 0) {
errflag |= ERRFLAG_ERROR;
@@ -4537,7 +4545,7 @@ getoutput(char *cmd, int qt)
LinkList retval;
zclose(pipes[1]);
- retval = readoutput(pipes[0], qt);
+ retval = readoutput(pipes[0], qt, 0);
fdtable[pipes[0]] = FDT_UNUSED;
waitforpid(pid, 0); /* unblocks */
lastval = cmdoutval;
@@ -4562,7 +4570,7 @@ getoutput(char *cmd, int qt)
/**/
mod_export LinkList
-readoutput(int in, int qt)
+readoutput(int in, int qt, int *readerror)
{
LinkList ret;
char *buf, *ptr;
@@ -4591,6 +4599,8 @@ readoutput(int in, int qt)
}
*ptr++ = c;
}
+ if (readerror && ferror(fin))
+ *readerror = errno;
fclose(fin);
while (cnt && ptr[-1] == '\n')
ptr--, cnt--;
next prev parent reply other threads:[~2018-03-15 7:12 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CGME20180314103335epcas4p30222f0df02adda27cbddbe62075ff9ad@epcas4p3.samsung.com>
2018-03-14 10:32 ` Stephane Chazelas
2018-03-14 10:54 ` Peter Stephenson
2018-03-14 14:42 ` Stephane Chazelas
2018-03-14 14:50 ` Peter Stephenson
2018-03-15 7:12 ` Stephane Chazelas [this message]
2018-03-15 7:25 ` EILSEQ in the C locale? (Was: $(<nofile) doesn't set $? to non-zero) Stephane Chazelas
2018-03-19 0:09 ` Bart Schaefer
2018-03-15 9:23 ` $(<nofile) doesn't set $? to non-zero Peter Stephenson
2018-03-15 11:10 ` Stephane Chazelas
2018-03-16 8:24 ` Stephane Chazelas
2018-03-14 11:04 ` Stephane Chazelas
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