Date: Thu, 19 Mar 2015 15:13:43 +0800 From: Tiwei Bie <btw@mail.ustc.edu.cn> To: mjguzik@gmail.com Cc: freebsd-hackers@freebsd.org Subject: [PATCH] Finish the task 'Fix corefilename race' Message-ID: <1426749223-18118-1-git-send-email-btw@mail.ustc.edu.cn>
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Hi, Mateusz!
I have finished the task: Fix corefilename race [1].
Following is my patch:
---
sys/kern/kern_sig.c | 22 ++++++++++++++++++++--
1 file changed, 20 insertions(+), 2 deletions(-)
diff --git a/sys/kern/kern_sig.c b/sys/kern/kern_sig.c
index 58d9707..a1421cb 100644
--- a/sys/kern/kern_sig.c
+++ b/sys/kern/kern_sig.c
@@ -3090,8 +3090,24 @@ static int compress_user_cores = 0;
#endif
static char corefilename[MAXPATHLEN] = {"%N.core"};
-SYSCTL_STRING(_kern, OID_AUTO, corefile, CTLFLAG_RWTUN, corefilename,
- sizeof(corefilename), "Process corefile name format string");
+
+static struct sx corefilename_lock;
+SX_SYSINIT(corefilename_init, &corefilename_lock, "corefilename lock");
+
+static int
+sysctl_kern_corefile(SYSCTL_HANDLER_ARGS)
+{
+ int error;
+
+ sx_xlock(&corefilename_lock);
+ error = sysctl_handle_string(oidp, corefilename, MAXPATHLEN, req);
+ sx_xunlock(&corefilename_lock);
+
+ return (error);
+}
+SYSCTL_PROC(_kern, OID_AUTO, corefile, CTLTYPE_STRING | CTLFLAG_RWTUN |
+ CTLFLAG_MPSAFE, 0, 0, sysctl_kern_corefile, "A",
+ "Process corefile name format string");
/*
* corefile_open(comm, uid, pid, td, compress, vpp, namep)
@@ -3120,6 +3136,7 @@ corefile_open(const char *comm, uid_t uid, pid_t pid, struct thread *td,
name = malloc(MAXPATHLEN, M_TEMP, M_WAITOK | M_ZERO);
indexpos = -1;
(void)sbuf_new(&sb, name, MAXPATHLEN, SBUF_FIXEDLEN);
+ sx_slock(&corefilename_lock);
for (i = 0; format[i] != '\0'; i++) {
switch (format[i]) {
case '%': /* Format character */
@@ -3162,6 +3179,7 @@ corefile_open(const char *comm, uid_t uid, pid_t pid, struct thread *td,
break;
}
}
+ sx_sunlock(&corefilename_lock);
free(hostname, M_TEMP);
if (compress)
sbuf_printf(&sb, GZ_SUFFIX);
--
2.1.2
[1] https://wiki.freebsd.org/JuniorJobs#Fix_corefilename_race
Best regards,
Tiwei Bie
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