Re: "target remote | " stderr

Vladimir Prus
2007-01-31T14:35:50Z

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Daniel Jacobowitz wrote:

>> Pass stderr of program run with "target remote |"
>> via gdb_stderr.
>> * serial.c (serial_open): Set error_fd to -1.
>> * serial.h (struct serial): New field error_fd.
>> * ser-pipe.c (pipe_open): Create another pair
>> of sockets. Pass stderr to gdb.
>> * ser-base.c (generic_readchar): Check if there's
>> anything in stderr channel and route that to gdb_stderr.
>
> The patch seems OK to me; though I would like to be sure we can
> implement this for MinGW before we get too used to the idea.

Implementing for MinGW required modifying libiberty so that
it can catch stderr to a pipe. Here's a patch for gdb that
relies on the libiberty patch. Does this sound OK
provided libiberty patch is approved?

- Volodya

Pass stderr of program run with "target remote |"
via gdb_stderr.
* serial.c (serial_open): Set error_fd to -1.
* serial.h (struct serial): New field error_fd.
* ser-pipe.c (pipe_open): Create another pair
of sockets. Pass stderr to gdb.
* ser-mingw.c (pipe_windows_open): Pass
PEX_STDERR_TO_PIPE to pex_run. Initialize
sd->error_fd.
* ser-base.c (generic_readchar): Check if there's
anything in stderr channel and route that to gdb_stderr.

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--- gdb/serial.c (/patches/gdb/mingw_cpp_declarations/gdb_mainline) (revision 3263)
+++ gdb/serial.c (/patches/gdb/remote_stderr_try2/gdb_mainline) (revision 3263)
@@ -211,6 +211,7 @@ serial_open (const char *name)

scb->bufcnt = 0;
scb->bufp = scb->buf;
+ scb->error_fd = -1;

if (scb->ops->open (scb, open_name))
{
--- gdb/serial.h (/patches/gdb/mingw_cpp_declarations/gdb_mainline) (revision 3263)
+++ gdb/serial.h (/patches/gdb/remote_stderr_try2/gdb_mainline) (revision 3263)
@@ -191,6 +191,12 @@ extern int serial_debug_p (struct serial
struct serial
{
int fd; /* File descriptor */
+ int error_fd; /* File descriptor for a separate
+ error stream that should be
+ immediately forwarded to gdb_stderr.
+ This may be -1.
+ If != -1, this descriptor should
+ be non-blocking. */
struct serial_ops *ops; /* Function vector */
void *state; /* Local context info for open FD */
serial_ttystate ttystate; /* Not used (yet) */
--- gdb/ser-pipe.c (/patches/gdb/mingw_cpp_declarations/gdb_mainline) (revision 3263)
+++ gdb/ser-pipe.c (/patches/gdb/remote_stderr_try2/gdb_mainline) (revision 3263)
@@ -62,9 +62,12 @@ pipe_open (struct serial *scb, const cha
* published in UNIX Review, Vol. 6, No. 8.
*/
int pdes[2];
+ int err_pdes[2];
int pid;
if (socketpair (AF_UNIX, SOCK_STREAM, 0, pdes) < 0)
return -1;
+ if (socketpair (AF_UNIX, SOCK_STREAM, 0, err_pdes) < 0)
+ return -1;

/* Create the child process to run the command in. Note that the
apparent call to vfork() below *might* actually be a call to
@@ -77,9 +80,18 @@ pipe_open (struct serial *scb, const cha
{
close (pdes[0]);
close (pdes[1]);
+ close (err_pdes[0]);
+ close (err_pdes[1]);
return -1;
}

+ if (fcntl (err_pdes[0], F_SETFL, O_NONBLOCK) == -1)
+ {
+ close (err_pdes[0]);
+ close (err_pdes[1]);
+ err_pdes[0] = err_pdes[1] = -1;
+ }
+
/* Child. */
if (pid == 0)
{
@@ -91,6 +103,13 @@ pipe_open (struct serial *scb, const cha
close (pdes[1]);
}
dup2 (STDOUT_FILENO, STDIN_FILENO);
+
+ if (err_pdes[0] != -1)
+ {
+ close (err_pdes[0]);
+ dup2 (err_pdes[1], STDERR_FILENO);
+ close (err_pdes[1]);
+ }
#if 0
/* close any stray FD's - FIXME - how? */
/* POSIX.2 B.3.2.2 "popen() shall ensure that any streams
@@ -109,6 +128,7 @@ pipe_open (struct serial *scb, const cha
state = XMALLOC (struct pipe_state);
state->pid = pid;
scb->fd = pdes[0];
+ scb->error_fd = err_pdes[0];
scb->state = state;

/* If we don't do this, GDB simply exits when the remote side dies. */
--- gdb/ser-base.c (/patches/gdb/mingw_cpp_declarations/gdb_mainline) (revision 3263)
+++ gdb/ser-base.c (/patches/gdb/remote_stderr_try2/gdb_mainline) (revision 3263)
@@ -314,6 +314,33 @@ generic_readchar (struct serial *scb, in
int (do_readchar) (struct serial *scb, int timeout))
{
int ch;
+
+ /* Read any error output we might have. */
+ if (scb->error_fd != -1)
+ {
+ ssize_t s;
+ char buf[81];
+ while ((s = read (scb->error_fd, &buf, 80)) > 0)
+ {
+ char *current;
+ char *newline;
+ /* In theory, embedded newlines are not a problem.
+ But for MI, we want each output line to have just
+ one newline for legibility. So output things
+ in newline chunks. */
+ buf[s] = '\0';
+ current = buf;
+ while ((newline = strstr (current, "\n")) != NULL)
+ {
+ *newline = '\0';
+ fputs_unfiltered (current, gdb_stderr);
+ fputs_unfiltered ("\n", gdb_stderr);
+ current = newline + 1;
+ }
+ fputs_unfiltered (current, gdb_stderr);
+ }
+ }
+
if (scb->bufcnt > 0)
{
ch = *scb->bufp;
--- gdb/ser-mingw.c (/patches/gdb/mingw_cpp_declarations/gdb_mainline) (revision 3263)
+++ gdb/ser-mingw.c (/patches/gdb/remote_stderr_try2/gdb_mainline) (revision 3263)
@@ -697,6 +697,7 @@ static int
pipe_windows_open (struct serial *scb, const char *name)
{
struct pipe_state *ps;
+ FILE *pex_stderr;

char **argv = buildargv (name);
struct cleanup *back_to = make_cleanup_freeargv (argv);
@@ -717,7 +718,8 @@ pipe_windows_open (struct serial *scb, c
{
int err;
const char *err_msg
- = pex_run (ps->pex, PEX_SEARCH | PEX_BINARY_INPUT | PEX_BINARY_OUTPUT,
+ = pex_run (ps->pex, PEX_SEARCH | PEX_BINARY_INPUT | PEX_BINARY_OUTPUT
+ | PEX_STDERR_TO_PIPE,
argv[0], argv, NULL, NULL,
&err);

@@ -739,8 +741,13 @@ pipe_windows_open (struct serial *scb, c
ps->output = pex_read_output (ps->pex, 1);
if (! ps->output)
goto fail;
-
scb->fd = fileno (ps->output);
+
+ pex_stderr = pex_read_err (ps->pex, 1);
+ if (! pex_stderr)
+ goto fail;
+ scb->error_fd = fileno (pex_stderr);
+
scb->state = (void *) ps;

discard_cleanups (back_to);

Property changes on:
___________________________________________________________________
Name: csl:base
+/all/patches/gdb/mingw_cpp_declarations/gdb_mainline