From: Josselin Poiret via "Bug reports for GUILE, GNU's Ubiquitous Extension Language" <bug-guile@gnu.org>
To: "Ludovic Courtès" <ludo@gnu.org>
Cc: 52835@debbugs.gnu.org, Timothy Sample <samplet@ngyro.com>,
Josselin Poiret <dev@jpoiret.xyz>
Subject: bug#52835: [PATCH v6 2/3] Make system* and piped-process internally use spawn.
Date: Thu, 22 Dec 2022 13:49:09 +0100 [thread overview]
Message-ID: <ca962003ea413100f09d8ebe439392627f168f4d.1671710701.git.dev@jpoiret.xyz> (raw)
In-Reply-To: <cover.1671710701.git.dev@jpoiret.xyz>
* libguile/posix.c (scm_system_star, scm_piped_process): Use do_spawn.
(start_child): Remove function.
---
libguile/posix.c | 181 ++++++++++-------------------------------------
1 file changed, 39 insertions(+), 142 deletions(-)
diff --git a/libguile/posix.c b/libguile/posix.c
index e92625483..f9c36d7ac 100644
--- a/libguile/posix.c
+++ b/libguile/posix.c
@@ -1308,125 +1308,6 @@ SCM_DEFINE (scm_fork, "primitive-fork", 0, 0, 0,
#undef FUNC_NAME
#endif /* HAVE_FORK */
-#ifdef HAVE_FORK
-/* 'renumber_file_descriptor' is a helper function for 'start_child'
- below, and is specialized for that particular environment where it
- doesn't make sense to report errors via exceptions. It uses dup(2)
- to duplicate the file descriptor FD, closes the original FD, and
- returns the new descriptor. If dup(2) fails, print an error message
- to ERR and abort. */
-static int
-renumber_file_descriptor (int fd, int err)
-{
- int new_fd;
-
- do
- new_fd = dup (fd);
- while (new_fd == -1 && errno == EINTR);
-
- if (new_fd == -1)
- {
- /* At this point we are in the child process before exec. We
- cannot safely raise an exception in this environment. */
- const char *msg = strerror (errno);
- fprintf (fdopen (err, "a"), "start_child: dup failed: %s\n", msg);
- _exit (127); /* Use exit status 127, as with other exec errors. */
- }
-
- close (fd);
- return new_fd;
-}
-#endif /* HAVE_FORK */
-
-#ifdef HAVE_FORK
-#define HAVE_START_CHILD 1
-/* Since Guile uses threads, we have to be very careful to avoid calling
- functions that are not async-signal-safe in the child. That's why
- this function is implemented in C. */
-static pid_t
-start_child (const char *exec_file, char **exec_argv,
- int reading, int c2p[2], int writing, int p2c[2],
- int in, int out, int err)
-{
- int pid;
- int max_fd = 1024;
-
-#if defined (HAVE_GETRLIMIT) && defined (RLIMIT_NOFILE)
- {
- struct rlimit lim = { 0, 0 };
- if (getrlimit (RLIMIT_NOFILE, &lim) == 0)
- max_fd = lim.rlim_cur;
- }
-#endif
-
- pid = fork ();
-
- if (pid != 0)
- /* The parent, with either and error (pid == -1), or the PID of the
- child. Return directly in either case. */
- return pid;
-
- /* The child. */
- if (reading)
- close (c2p[0]);
- if (writing)
- close (p2c[1]);
-
- /* Close all file descriptors in ports inherited from the parent
- except for in, out, and err. Heavy-handed, but robust. */
- while (max_fd--)
- if (max_fd != in && max_fd != out && max_fd != err)
- close (max_fd);
-
- /* Ignore errors on these open() calls. */
- if (in == -1)
- in = open ("/dev/null", O_RDONLY);
- if (out == -1)
- out = open ("/dev/null", O_WRONLY);
- if (err == -1)
- err = open ("/dev/null", O_WRONLY);
-
- if (in > 0)
- {
- if (out == 0)
- out = renumber_file_descriptor (out, err);
- if (err == 0)
- err = renumber_file_descriptor (err, err);
- do dup2 (in, 0); while (errno == EINTR);
- close (in);
- }
- if (out > 1)
- {
- if (err == 1)
- err = renumber_file_descriptor (err, err);
- do dup2 (out, 1); while (errno == EINTR);
- if (out > 2)
- close (out);
- }
- if (err > 2)
- {
- do dup2 (err, 2); while (errno == EINTR);
- close (err);
- }
-
- execvp (exec_file, exec_argv);
-
- /* The exec failed! There is nothing sensible to do. */
- {
- const char *msg = strerror (errno);
- fprintf (fdopen (2, "a"), "In execvp of %s: %s\n",
- exec_file, msg);
- }
-
- /* Use exit status 127, like shells in this case, as per POSIX
- <http://pubs.opengroup.org/onlinepubs/007904875/utilities/xcu_chap02.html#tag_02_09_01_01>. */
- _exit (127);
-
- /* Not reached. */
- return -1;
-}
-#endif
-
static int
do_spawn (char *exec_file, char **exec_argv, char **exec_env, int in, int out, int err)
{
@@ -1507,7 +1388,7 @@ SCM_DEFINE (scm_spawn_process, "spawn*", 5, 0, 0,
}
#undef FUNC_NAME
-#ifdef HAVE_START_CHILD
+#ifdef HAVE_FORK
static SCM
scm_piped_process (SCM prog, SCM args, SCM from, SCM to)
#define FUNC_NAME "piped-process"
@@ -1519,6 +1400,7 @@ scm_piped_process (SCM prog, SCM args, SCM from, SCM to)
int pid;
char *exec_file;
char **exec_argv;
+ char **exec_env = environ;
exec_file = scm_to_locale_string (prog);
exec_argv = scm_i_allocate_string_pointers (scm_cons (prog, args));
@@ -1551,27 +1433,44 @@ scm_piped_process (SCM prog, SCM args, SCM from, SCM to)
in = SCM_FPORT_FDES (port);
}
- pid = start_child (exec_file, exec_argv, reading, c2p, writing, p2c,
- in, out, err);
+ pid = do_spawn (exec_file, exec_argv, exec_env, in, out, err);
+ int errno_save = errno;
if (pid == -1)
{
- int errno_save = errno;
- free (exec_file);
- if (reading)
- {
- close (c2p[0]);
- close (c2p[1]);
- }
- if (writing)
- {
- close (p2c[0]);
- close (p2c[1]);
- }
- errno = errno_save;
- SCM_SYSERROR;
+ /* TODO This is a compatibility shim until the next major release */
+ switch (errno) {
+ /* If the error seemingly comes from fork */
+ case EAGAIN:
+ case ENOMEM:
+ case ENOSYS:
+ free (exec_file);
+
+ if (reading)
+ {
+ close (c2p[0]);
+ }
+ if (writing)
+ {
+ close (p2c[1]);
+ }
+ errno = errno_save;
+ SCM_SYSERROR;
+ break;
+ /* Else create a dummy process that exits with value 127 */
+ default:
+ dprintf (err, "In execvp of %s: %s\n", exec_file,
+ strerror (errno_save));
+ pid = fork ();
+ if (pid == -1)
+ SCM_SYSERROR;
+ if (pid == 0)
+ _exit (127);
+ }
}
+ free (exec_file);
+
if (reading)
close (c2p[1]);
if (writing)
@@ -1651,7 +1550,7 @@ SCM_DEFINE (scm_system_star, "system*", 0, 0, 1,
return scm_from_int (status);
}
#undef FUNC_NAME
-#endif /* HAVE_START_CHILD */
+#endif /* HAVE_FORK */
#ifdef HAVE_UNAME
SCM_DEFINE (scm_uname, "uname", 0, 0, 0,
@@ -2497,13 +2396,13 @@ SCM_DEFINE (scm_gethostname, "gethostname", 0, 0, 0,
#endif /* HAVE_GETHOSTNAME */
\f
-#ifdef HAVE_START_CHILD
+#ifdef HAVE_FORK
static void
scm_init_popen (void)
{
scm_c_define_gsubr ("piped-process", 2, 2, 0, scm_piped_process);
}
-#endif /* HAVE_START_CHILD */
+#endif /* HAVE_FORK */
void
scm_init_posix ()
@@ -2621,12 +2520,10 @@ scm_init_posix ()
#ifdef HAVE_FORK
scm_add_feature ("fork");
-#endif /* HAVE_FORK */
-#ifdef HAVE_START_CHILD
scm_add_feature ("popen");
scm_c_register_extension ("libguile-" SCM_EFFECTIVE_VERSION,
"scm_init_popen",
(scm_t_extension_init_func) scm_init_popen,
NULL);
-#endif /* HAVE_START_CHILD */
+#endif /* HAVE_FORK */
}
--
2.38.1
next prev parent reply other threads:[~2022-12-22 12:49 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-27 21:25 bug#52835: [PATCH 0/2] Fix spawning a child not setting standard fds properly Josselin Poiret via Bug reports for GUILE, GNU's Ubiquitous Extension Language
2021-12-27 21:35 ` bug#52835: [PATCH 1/2] Fix child spawning closing standard fds prematurely Josselin Poiret via Bug reports for GUILE, GNU's Ubiquitous Extension Language
2021-12-27 21:35 ` bug#52835: [PATCH 2/2] Remove unused renumber_file_descriptor Josselin Poiret via Bug reports for GUILE, GNU's Ubiquitous Extension Language
2021-12-27 21:49 ` bug#52835: [PATCH v2 " Josselin Poiret via Bug reports for GUILE, GNU's Ubiquitous Extension Language
2021-12-28 15:40 ` bug#52835: [PATCH 0/2] Fix spawning a child not setting standard fds properly Timothy Sample
2021-12-28 17:25 ` Josselin Poiret via Bug reports for GUILE, GNU's Ubiquitous Extension Language
2022-02-07 16:55 ` bug#52835: [PATCH v3] Fix child spawning closing standard fds prematurely Josselin Poiret via Bug reports for GUILE, GNU's Ubiquitous Extension Language
2022-05-28 12:46 ` bug#52835: [PATCH v4 0/4] Improve safety of start_child and piped-process Josselin Poiret via Bug reports for GUILE, GNU's Ubiquitous Extension Language
2022-05-28 12:46 ` bug#52835: [PATCH v4 1/4] Fix child spawning closing standard fds prematurely Josselin Poiret via Bug reports for GUILE, GNU's Ubiquitous Extension Language
2022-05-28 12:46 ` bug#52835: [PATCH v4 2/4] Avoid double closes in piped-process Josselin Poiret via Bug reports for GUILE, GNU's Ubiquitous Extension Language
2022-05-28 12:46 ` bug#52835: [PATCH v4 3/4] Remove useless closing code in start_child Josselin Poiret via Bug reports for GUILE, GNU's Ubiquitous Extension Language
2022-05-28 12:46 ` bug#52835: [PATCH v4 4/4] Make start_child propagate the child errno to the parent Josselin Poiret via Bug reports for GUILE, GNU's Ubiquitous Extension Language
2022-09-05 6:48 ` bug#52835: [PATCH v5 0/3] Move spawning procedures to posix_spawn Josselin Poiret via Bug reports for GUILE, GNU's Ubiquitous Extension Language
2022-09-05 6:48 ` bug#52835: [PATCH v5 1/3] Update gnulib to 0.1.5414-8204d and add posix_spawn, posix_spawnp Josselin Poiret via Bug reports for GUILE, GNU's Ubiquitous Extension Language
2022-09-05 6:48 ` bug#52835: [PATCH v5 2/3] Add spawn* Josselin Poiret via Bug reports for GUILE, GNU's Ubiquitous Extension Language
2022-09-05 6:48 ` bug#52835: [PATCH v5 3/3] Move popen and posix procedures to spawn* Josselin Poiret via Bug reports for GUILE, GNU's Ubiquitous Extension Language
2022-11-29 15:05 ` bug#52835: [PATCH 0/2] Fix spawning a child not setting standard fds properly Ludovic Courtès
2022-12-11 20:16 ` Josselin Poiret via Bug reports for GUILE, GNU's Ubiquitous Extension Language
2022-12-12 23:49 ` Ludovic Courtès
2022-12-22 12:49 ` bug#52835: [PATCH v6 0/3] Move spawning procedures to posix_spawn Josselin Poiret via Bug reports for GUILE, GNU's Ubiquitous Extension Language
2022-12-22 12:49 ` bug#52835: [PATCH v6 1/3] Add spawn* Josselin Poiret via Bug reports for GUILE, GNU's Ubiquitous Extension Language
2022-12-22 12:49 ` Josselin Poiret via Bug reports for GUILE, GNU's Ubiquitous Extension Language [this message]
2022-12-22 12:49 ` bug#52835: [PATCH v6 3/3] Move popen and posix procedures to spawn* Josselin Poiret via Bug reports for GUILE, GNU's Ubiquitous Extension Language
2022-12-23 10:53 ` bug#52835: [PATCH 0/2] Fix spawning a child not setting standard fds properly Ludovic Courtès
2022-12-23 17:15 ` Josselin Poiret via Bug reports for GUILE, GNU's Ubiquitous Extension Language
2022-12-23 17:17 ` bug#52835: [PATCH v7 1/2] Add spawn* and spawn Josselin Poiret via Bug reports for GUILE, GNU's Ubiquitous Extension Language
2022-12-23 17:17 ` bug#52835: [PATCH v7 2/2] Make system* and piped-process internally use spawn Josselin Poiret via Bug reports for GUILE, GNU's Ubiquitous Extension Language
2022-12-25 17:04 ` bug#52835: [PATCH 0/2] Fix spawning a child not setting standard fds properly Ludovic Courtès
2022-12-25 17:03 ` Ludovic Courtès
2022-12-25 16:58 ` Ludovic Courtès
2023-01-07 16:07 ` Josselin Poiret via Bug reports for GUILE, GNU's Ubiquitous Extension Language
2023-01-07 16:07 ` bug#52835: [PATCH v8 1/2] Add spawn Josselin Poiret via Bug reports for GUILE, GNU's Ubiquitous Extension Language
2023-01-07 16:07 ` bug#52835: [PATCH v8 2/2] Make system* and piped-process internally use spawn Josselin Poiret via Bug reports for GUILE, GNU's Ubiquitous Extension Language
2023-01-12 22:02 ` bug#52835: [PATCH 0/2] Fix spawning a child not setting standard fds properly Ludovic Courtès
2023-01-13 1:11 ` Andrew Whatson via Bug reports for GUILE, GNU's Ubiquitous Extension Language
2023-01-13 15:20 ` Ludovic Courtès
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