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Re: /dev/fd/n bug in gawk 3.1.5
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From: |
Aharon Robbins |
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Subject: |
Re: /dev/fd/n bug in gawk 3.1.5 |
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Date: |
Sun, 18 Jun 2006 22:44:53 +0300 |
Greetings. Re this:
> Date: Tue, 13 Jun 2006 17:49:58 -0700
> From: "John H. DuBois III" <address@hidden>
> Subject: /dev/fd/n bug in gawk 3.1.5
> To: address@hidden
>
> $ cat /dev/fd/4 /dev/fd/5 4<tm1 5<tm2
> Contents of tm1
> Contents of tm2
> $ gawk 1 /dev/fd/4 /dev/fd/5 4<tm1 5<tm2
> Contents of tm1
> Contents of tm1
>
>
> gawk: (FILENAME=/dev/fd/5 FNR=3) fatal: error reading input file `/dev/fd/4':
> Bad file number
The bug fix I posted yesterday was incomplete. It solved the command line
problem
but (as I suspected) bugs were still lurking, as shown by this test program.
---------------------------------------------
BEGIN {
while (1) {
if ((getline l1 < "/dev/fd/4") <= 0)
break
print l1
if ((getline l2 < "/dev/fd/5") <= 0)
break
print l2
}
}
---------------------------------------------
Try it with something like
gawk -f foo.awk 4< f1 5< f2
Or by something like this:
$ gawk 1 /dev/pid
gawk: cmd. line:1: warning: use `PROCINFO["pid"]' instead of `/dev/pid'
12102
gawk: (FILENAME=/dev/pid FNR=1) fatal: error reading input file
`(null)': Bad file descriptor
Here is a complete patch.
Thanks for helping me get this straightened out!
Arnold
------------------------- cut here --------------------------------
Sun Jun 18 22:27:25 2006 Arnold D. Robbins <address@hidden>
Repair internal names like /dev/user, /dev/pid, as well as /dev/fd/N,
which have been broken for a long time but noone noticed.
* io.c (is_internal): new macro to check for internal file like
`/dev/user'.
(spec_setup): Reduce to two parameters, allocate logic is always true.
Add IOP_NO_FREE to flag.
(pidopen, useropen): Return `IOBUF *' instead of int. Fix
logic to test if `iop' parameter is NULL and if so to allocate it.
(specfdopen,): Return `IOBUF *' instead of int. Fix
logic to test if `iop' parameter is NULL and if so to allocate it.
Don't set IOP_NO_FREE in flag.
(iop_open): Remove `IOBUF iob' field from `struct internal' and its use
and the use of `spec_setup' from the code here. Change the check in the
call to the open function to look for NULL.
(get_a_record): Use `is_internal' in initial check for filling the
buffer to not try to call `read' on internal files. If true, set
the IOP_AT_EOF in the flag and return EOF.
--- ../gawk-3.1.5/io.c 2005-07-26 21:07:43.000000000 +0300
+++ io.c 2006-06-18 22:31:08.076682904 +0300
@@ -110,6 +110,7 @@
#define at_eof(iop) ((iop->flag & IOP_AT_EOF) != 0)
#define has_no_data(iop) (iop->dataend == NULL)
#define no_data_left(iop) (iop->off >= iop->dataend)
+#define is_internal(iop) ((iop->flag & IOP_IS_INTERNAL) != 0)
/* The key point to the design is to split out the code that searches through
*/
/* a buffer looking for the record and the terminator into separate routines,
*/
/* with a higher-level routine doing the reading of data and buffer
management. */
@@ -163,10 +164,10 @@
static int gawk_pclose P((struct redirect *rp));
static int do_pathopen P((const char *file));
static int str2mode P((const char *mode));
-static void spec_setup P((IOBUF *iop, int len, int allocate));
-static int specfdopen P((IOBUF *iop, const char *name, const char *mode));
-static int pidopen P((IOBUF *iop, const char *name, const char *mode));
-static int useropen P((IOBUF *iop, const char *name, const char *mode));
+static void spec_setup P((IOBUF *iop, int len));
+static IOBUF *specfdopen P((IOBUF *iop, const char *name, const char *mode));
+static IOBUF *pidopen P((IOBUF *iop, const char *name, const char *mode));
+static IOBUF *useropen P((IOBUF *iop, const char *name, const char *mode));
static int two_way_open P((const char *str, struct redirect *rp));
static int pty_vs_pipe P((const char *command));
@@ -1422,30 +1423,24 @@
/* spec_setup --- setup an IOBUF for a special internal file */
static void
-spec_setup(IOBUF *iop, int len, int allocate)
+spec_setup(IOBUF *iop, int len)
{
char *cp;
- if (allocate) {
- emalloc(cp, char *, len+2, "spec_setup");
- iop->buf = cp;
- } else {
- len = strlen(iop->buf);
- iop->buf[len++] = '\n'; /* get_a_record clobbered it */
- iop->buf[len] = '\0'; /* just in case */
- }
+ emalloc(cp, char *, len+2, "spec_setup");
+ iop->buf = cp;
iop->off = iop->buf;
iop->count = 0;
iop->size = len;
iop->end = iop->buf + len;
iop->dataend = iop->end;
iop->fd = -1;
- iop->flag = IOP_IS_INTERNAL | IOP_AT_START;
+ iop->flag = IOP_IS_INTERNAL | IOP_AT_START | IOP_NO_FREE;
}
/* specfdopen --- open an fd special file */
-static int
+static IOBUF *
specfdopen(IOBUF *iop, const char *name, const char *mode)
{
int fd;
@@ -1453,17 +1448,14 @@
fd = devopen(name, mode);
if (fd == INVALID_HANDLE)
- return INVALID_HANDLE;
- tp = iop_alloc(fd, name, NULL);
+ return NULL;
+ tp = iop_alloc(fd, name, iop);
if (tp == NULL) {
/* don't leak fd's */
close(fd);
- return INVALID_HANDLE;
+ return NULL;
}
- *iop = *tp;
- iop->flag |= IOP_NO_FREE;
- free(tp);
- return 0;
+ return tp;
}
#ifdef GETPGRP_VOID
@@ -1474,7 +1466,7 @@
/* pidopen --- "open" /dev/pid, /dev/ppid, and /dev/pgrpid */
-static int
+static IOBUF *
pidopen(IOBUF *iop, const char *name, const char *mode ATTRIBUTE_UNUSED)
{
char tbuf[BUFSIZ];
@@ -1483,6 +1475,12 @@
warning(_("use `PROCINFO[\"%s\"]' instead of `%s'"), cp, name);
+ if (iop == NULL) {
+ iop = iop_alloc(INVALID_HANDLE, name, iop);
+ if (iop == NULL)
+ return NULL;
+ }
+
if (name[6] == 'g')
sprintf(tbuf, "%d\n", (int) getpgrp(getpgrp_arg()));
else if (name[6] == 'i')
@@ -1490,9 +1488,9 @@
else
sprintf(tbuf, "%d\n", (int) getppid());
i = strlen(tbuf);
- spec_setup(iop, i, TRUE);
+ spec_setup(iop, i);
strcpy(iop->buf, tbuf);
- return 0;
+ return iop;
}
/* useropen --- "open" /dev/user */
@@ -1507,7 +1505,7 @@
* supplementary group set.
*/
-static int
+static IOBUF *
useropen(IOBUF *iop, const char *name ATTRIBUTE_UNUSED, const char *mode
ATTRIBUTE_UNUSED)
{
char tbuf[BUFSIZ], *cp;
@@ -1515,6 +1513,12 @@
warning(_("use `PROCINFO[...]' instead of `/dev/user'"));
+ if (iop == NULL) {
+ iop = iop_alloc(INVALID_HANDLE, name, iop);
+ if (iop == NULL)
+ return NULL;
+ }
+
sprintf(tbuf, "%d %d %d %d", (int) getuid(), (int) geteuid(), (int)
getgid(), (int) getegid());
cp = tbuf + strlen(tbuf);
@@ -1529,9 +1533,9 @@
*cp++ = '\0';
i = strlen(tbuf);
- spec_setup(iop, i, TRUE);
+ spec_setup(iop, i);
strcpy(iop->buf, tbuf);
- return 0;
+ return iop;
}
/* iop_open --- handle special and regular files for input */
@@ -1544,8 +1548,7 @@
static struct internal {
const char *name;
int compare;
- int (*fp) P((IOBUF *, const char *, const char *));
- IOBUF iob;
+ IOBUF *(*fp) P((IOBUF *, const char *, const char *));
} table[] = {
{ "/dev/fd/", 8, specfdopen },
{ "/dev/stdin", 10, specfdopen },
@@ -1570,12 +1573,7 @@
for (i = 0; i < devcount; i++) {
if (STREQN(name, table[i].name, table[i].compare)) {
- iop = & table[i].iob;
-
- if (iop->buf != NULL) {
- spec_setup(iop, 0, FALSE);
- return iop;
- } else if ((*table[i].fp)(iop, name, mode) == 0)
+ if ((iop = (*table[i].fp)(iop, name, mode)) !=
NULL)
return iop;
else {
warning(_("could not open `%s', mode
`%s'"),
@@ -2906,6 +2908,10 @@
/* <fill initial buffer>=
*/
if (has_no_data(iop) || no_data_left(iop)) {
+ if (is_internal(iop)) {
+ iop->flag |= IOP_AT_EOF;
+ return EOF;
+ }
iop->count = read(iop->fd, iop->buf, iop->readsize);
if (iop->count == 0) {
iop->flag |= IOP_AT_EOF;