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[libiberty patch] PEX-unix forking

Browse source 
https://gcc.gnu.org/ml/gcc-patches/2018-08/msg01170.html
	* pex-unix.c (pex_child_error): Delete.
	(pex_unix_exec_child): Commonize error paths to single message &
	exit.

From-SVN: r263679
This commit is contained in:
Nathan Sidwell 2018-08-21 00:01:50 +00:00 • committed by Nathan Sidwell
parent a7e94dc09a
commit 5c12a85534
2 changed files with 78 additions and 87 deletions
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6
libiberty/ChangeLog
View file

@ -1,3 +1,9 @@
2018-08-20 Nathan Sidwell <nathan@acm.org>
* pex-unix.c (pex_child_error): Delete.
(pex_unix_exec_child): Commonize error paths to single message &
exit.
2018-07-30 Tom Tromey <tom@tromey.com>
* cplus-dem.c (remember_Btype): Don't call memcpy with LEN==0.

159
libiberty/pex-unix.c
View file

@ -298,8 +298,6 @@ pex_wait (struct pex_obj *obj, pid_t pid, int *status, struct pex_time *time)
#endif /* ! defined (HAVE_WAITPID) */
#endif /* ! defined (HAVE_WAIT4) */
static void pex_child_error (struct pex_obj *, const char *, const char *, int)
ATTRIBUTE_NORETURN;
static int pex_unix_open_read (struct pex_obj *, const char *, int);
static int pex_unix_open_write (struct pex_obj *, const char *, int, int);
static pid_t pex_unix_exec_child (struct pex_obj *, int, const char *,
@ -366,28 +364,6 @@ pex_unix_close (struct pex_obj *obj ATTRIBUTE_UNUSED, int fd)
return close (fd);
}
/* Report an error from a child process. We don't use stdio routines,
because we might be here due to a vfork call. */
static void
pex_child_error (struct pex_obj *obj, const char *executable,
const char *errmsg, int err)
{
int retval = 0;
#define writeerr(s) retval |= (write (STDERR_FILE_NO, s, strlen (s)) < 0)
writeerr (obj->pname);
writeerr (": error trying to exec '");
writeerr (executable);
writeerr ("': ");
writeerr (errmsg);
writeerr (": ");
writeerr (xstrerror (err));
writeerr ("\n");
#undef writeerr
/* Exit with -2 if the error output failed, too. */
_exit (retval == 0 ? -1 : -2);
}
/* Execute a child. */
#if defined(HAVE_SPAWNVE) && defined(HAVE_SPAWNVPE)
@ -592,21 +568,22 @@ pex_unix_exec_child (struct pex_obj *obj, int flags, const char *executable,
int in, int out, int errdes,
int toclose, const char **errmsg, int *err)
{
pid_t pid;
pid_t pid = -1;
/* We declare these to be volatile to avoid warnings from gcc about
them being clobbered by vfork. */
volatile int sleep_interval;
volatile int sleep_interval = 1;
volatile int retries;
/* We vfork and then set environ in the child before calling execvp.
This clobbers the parent's environ so we need to restore it.
It would be nice to use one of the exec* functions that takes an
environment as a parameter, but that may have portability issues. */
environment as a parameter, but that may have portability
issues. */
char **save_environ = environ;
sleep_interval = 1;
pid = -1;
const char *bad_fn = NULL;
for (retries = 0; retries < 4; ++retries)
{
pid = vfork ();
@ -625,57 +602,76 @@ pex_unix_exec_child (struct pex_obj *obj, int flags, const char *executable,
case 0:
/* Child process. */
if (in != STDIN_FILE_NO)
if (!bad_fn && in != STDIN_FILE_NO)
{
if (dup2 (in, STDIN_FILE_NO) < 0)
pex_child_error (obj, executable, "dup2", errno);
if (close (in) < 0)
pex_child_error (obj, executable, "close", errno);
bad_fn = "dup2";
else if (close (in) < 0)
bad_fn = "close";
}
if (out != STDOUT_FILE_NO)
if (!bad_fn && out != STDOUT_FILE_NO)
{
if (dup2 (out, STDOUT_FILE_NO) < 0)
pex_child_error (obj, executable, "dup2", errno);
if (close (out) < 0)
pex_child_error (obj, executable, "close", errno);
bad_fn = "dup2";
else if (close (out) < 0)
bad_fn = "close";
}
if (errdes != STDERR_FILE_NO)
if (!bad_fn && errdes != STDERR_FILE_NO)
{
if (dup2 (errdes, STDERR_FILE_NO) < 0)
pex_child_error (obj, executable, "dup2", errno);
if (close (errdes) < 0)
pex_child_error (obj, executable, "close", errno);
bad_fn = "dup2";
else if (close (errdes) < 0)
bad_fn = "close";
}
if (toclose >= 0)
if (!bad_fn && toclose >= 0)
{
if (close (toclose) < 0)
pex_child_error (obj, executable, "close", errno);
bad_fn = "close";
}
if ((flags & PEX_STDERR_TO_STDOUT) != 0)
if (!bad_fn && (flags & PEX_STDERR_TO_STDOUT) != 0)
{
if (dup2 (STDOUT_FILE_NO, STDERR_FILE_NO) < 0)
pex_child_error (obj, executable, "dup2", errno);
bad_fn = "dup2";
}
if (!bad_fn)
{
if (env)
/* NOTE: In a standard vfork implementation this clobbers
the parent's copy of environ "too" (in reality there's
only one copy). This is ok as we restore it below. */
environ = (char**) env;
if ((flags & PEX_SEARCH) != 0)
{
execvp (executable, to_ptr32 (argv));
bad_fn = "execvp";
}
else
{
execv (executable, to_ptr32 (argv));
bad_fn = "execv";
}
}
if (env)
{
/* NOTE: In a standard vfork implementation this clobbers the
parent's copy of environ "too" (in reality there's only one copy).
This is ok as we restore it below. */
environ = (char**) env;
}
/* Something failed, report an error. We don't use stdio
routines, because we might be here due to a vfork call. */
{
ssize_t retval = 0;
int err = errno;
if ((flags & PEX_SEARCH) != 0)
{
execvp (executable, to_ptr32 (argv));
pex_child_error (obj, executable, "execvp", errno);
}
else
{
execv (executable, to_ptr32 (argv));
pex_child_error (obj, executable, "execv", errno);
}
#define writeerr(s) (retval |= write (STDERR_FILE_NO, s, strlen (s)))
writeerr (obj->pname);
writeerr (": error trying to exec '");
writeerr (executable);
writeerr ("': ");
writeerr (bad_fn);
writeerr (": ");
writeerr (xstrerror (err));
writeerr ("\n");
#undef writeerr
/* Exit with -2 if the error output failed, too. */
_exit (retval < 0 ? -2 : -1);
}
/* NOTREACHED */
return (pid_t) -1;
@ -689,32 +685,21 @@ pex_unix_exec_child (struct pex_obj *obj, int flags, const char *executable,
the child's copy of environ. */
environ = save_environ;
if (in != STDIN_FILE_NO)
if (!bad_fn && in != STDIN_FILE_NO)
if (close (in) < 0)
bad_fn = "close";
if (!bad_fn && out != STDOUT_FILE_NO)
if (close (out) < 0)
bad_fn = "close";
if (!bad_fn && errdes != STDERR_FILE_NO)
if (close (errdes) < 0)
bad_fn = "close";
if (bad_fn)
{
if (close (in) < 0)
{
*err = errno;
*errmsg = "close";
return (pid_t) -1;
}
}
if (out != STDOUT_FILE_NO)
{
if (close (out) < 0)
{
*err = errno;
*errmsg = "close";
return (pid_t) -1;
}
}
if (errdes != STDERR_FILE_NO)
{
if (close (errdes) < 0)
{
*err = errno;
*errmsg = "close";
return (pid_t) -1;
}
*err = errno;
*errmsg = bad_fn;
return (pid_t) -1;
}
return pid;