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Message-Id: <20200903112309.102601-8-sorear@fastmail.com>
Date: Thu, 3 Sep 2020 07:23:02 -0400
From: Stefan O'Rear <sorear@...tmail.com>
To: musl@...ts.openwall.com
Cc: Stefan O'Rear <sorear@...tmail.com>
Subject: [PATCH 07/14] Emulate wait4 using waitid
riscv32 and future architectures lack wait4.
---
src/internal/wait4_waitid.h | 1 +
src/linux/__wait4_waitid.c | 52 +++++++++++++++++++++++++++++++++++++
src/linux/wait4.c | 5 ++++
src/process/waitpid.c | 6 +++++
src/stdio/pclose.c | 6 +++++
src/unistd/faccessat.c | 6 ++++-
6 files changed, 75 insertions(+), 1 deletion(-)
create mode 100644 src/internal/wait4_waitid.h
create mode 100644 src/linux/__wait4_waitid.c
diff --git a/src/internal/wait4_waitid.h b/src/internal/wait4_waitid.h
new file mode 100644
index 00000000..0ef1b9b1
--- /dev/null
+++ b/src/internal/wait4_waitid.h
@@ -0,0 +1 @@
+hidden pid_t __wait4_waitid(pid_t pid, int *status, int options, void *kru, int cp);
diff --git a/src/linux/__wait4_waitid.c b/src/linux/__wait4_waitid.c
new file mode 100644
index 00000000..208f1631
--- /dev/null
+++ b/src/linux/__wait4_waitid.c
@@ -0,0 +1,52 @@
+#include <sys/wait.h>
+#include "syscall.h"
+#include "wait4_waitid.h"
+
+hidden pid_t __wait4_waitid(pid_t pid, int *status, int options, void *kru, int cp)
+{
+ idtype_t t;
+ int r;
+ siginfo_t info;
+
+ info.si_pid = 0;
+ if (pid < -1) {
+ t = P_PGID;
+ pid = -pid;
+ } else if (pid == -1) {
+ t = P_ALL;
+ } else if (pid == 0) {
+ t = P_PGID;
+ } else {
+ t = P_PID;
+ }
+
+ if (cp) r = __syscall_cp(SYS_waitid, t, pid, &info, options|WEXITED, kru);
+ else r = __syscall(SYS_waitid, t, pid, &info, options|WEXITED, kru);
+
+ if (r<0) return r;
+
+ if (info.si_pid && status) {
+ int sw=0;
+ switch (info.si_code) {
+ case CLD_CONTINUED:
+ sw = 0xffff;
+ break;
+ case CLD_DUMPED:
+ sw = info.si_status&0x7f | 0x80;
+ break;
+ case CLD_EXITED:
+ sw = (info.si_status&0xff) << 8;
+ break;
+ case CLD_KILLED:
+ sw = info.si_status&0x7f;
+ break;
+ case CLD_STOPPED:
+ case CLD_TRAPPED:
+ sw = ((info.si_status&0xff) << 8) + 0x7f;
+ break;
+ }
+ *status = sw;
+ }
+
+ return info.si_pid;
+}
diff --git a/src/linux/wait4.c b/src/linux/wait4.c
index 83650e34..e4d3a053 100644
--- a/src/linux/wait4.c
+++ b/src/linux/wait4.c
@@ -4,6 +4,7 @@
#include <string.h>
#include <errno.h>
#include "syscall.h"
+#include "wait4_waitid.h"
pid_t wait4(pid_t pid, int *status, int options, struct rusage *ru)
{
@@ -26,7 +27,11 @@ pid_t wait4(pid_t pid, int *status, int options, struct rusage *ru)
}
#endif
char *dest = ru ? (char *)&ru->ru_maxrss - 4*sizeof(long) : 0;
+#ifdef SYS_wait4
r = __syscall(SYS_wait4, pid, status, options, dest);
+#else
+ r = __wait4_waitid(pid, status, options, dest, 0);
+#endif
if (r>0 && ru && sizeof(time_t) > sizeof(long)) {
long kru[4];
memcpy(kru, dest, 4*sizeof(long));
diff --git a/src/process/waitpid.c b/src/process/waitpid.c
index 1b65bf05..49668822 100644
--- a/src/process/waitpid.c
+++ b/src/process/waitpid.c
@@ -1,7 +1,13 @@
+#define _GNU_SOURCE
#include <sys/wait.h>
#include "syscall.h"
+#include "wait4_waitid.h"
pid_t waitpid(pid_t pid, int *status, int options)
{
+#ifdef SYS_wait4
return syscall_cp(SYS_wait4, pid, status, options, 0);
+#else
+ return __syscall_ret(__wait4_waitid(pid, status, options, 0, 1));
+#endif
}
diff --git a/src/stdio/pclose.c b/src/stdio/pclose.c
index 080a4262..79e3d1d5 100644
--- a/src/stdio/pclose.c
+++ b/src/stdio/pclose.c
@@ -1,4 +1,6 @@
#include "stdio_impl.h"
+#include <sys/wait.h>
+#include "wait4_waitid.h"
#include <errno.h>
#include <unistd.h>
@@ -7,7 +9,11 @@ int pclose(FILE *f)
int status, r;
pid_t pid = f->pipe_pid;
fclose(f);
+#ifdef SYS_wait4
while ((r=__syscall(SYS_wait4, pid, &status, 0, 0)) == -EINTR);
+#else
+ while ((r=__wait4_waitid(pid, &status, 0, 0, 0)) == -EINTR);
+#endif
if (r<0) return __syscall_ret(r);
return status;
}
diff --git a/src/unistd/faccessat.c b/src/unistd/faccessat.c
index 76bbd4c7..8bf34995 100644
--- a/src/unistd/faccessat.c
+++ b/src/unistd/faccessat.c
@@ -34,7 +34,6 @@ int faccessat(int fd, const char *filename, int amode, int flag)
char stack[1024];
sigset_t set;
pid_t pid;
- int status;
int ret, p[2];
if (pipe2(p, O_CLOEXEC)) return __syscall_ret(-EBUSY);
@@ -48,7 +47,12 @@ int faccessat(int fd, const char *filename, int amode, int flag)
if (pid<0 || __syscall(SYS_read, p[0], &ret, sizeof ret) != sizeof(ret))
ret = -EBUSY;
__syscall(SYS_close, p[0]);
+#ifdef SYS_wait4
+ int status;
__syscall(SYS_wait4, pid, &status, __WCLONE, 0);
+#else
+ __syscall(SYS_waitid, P_PID, pid, &(siginfo_t){0}, __WCLONE|WEXITED, 0);
+#endif
__restore_sigs(&set);
--
2.25.4
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