svn commit: r302179 - head/usr.bin/gcore
Mark Johnston
markj at FreeBSD.org
Fri Jun 24 20:21:33 UTC 2016
Author: markj
Date: Fri Jun 24 20:21:32 2016
New Revision: 302179
URL: https://svnweb.freebsd.org/changeset/base/302179
Log:
gcore: Forward pending signals when detaching from the target.
Otherwise gcore's ptrace attach operation can race with delivery of a
signal and cause it to be lost.
In collaboration with: Suraj Raju <sraju at isilon.com>
Reviewed by: bdrewery
Approved by: re (gjb, kib)
MFC after: 2 weeks
Sponsored by: EMC / Isilon Storage Division
Modified:
head/usr.bin/gcore/elfcore.c
Modified: head/usr.bin/gcore/elfcore.c
==============================================================================
--- head/usr.bin/gcore/elfcore.c Fri Jun 24 20:00:39 2016 (r302178)
+++ head/usr.bin/gcore/elfcore.c Fri Jun 24 20:21:32 2016 (r302179)
@@ -126,6 +126,7 @@ static vm_map_entry_t readmap(pid_t);
static void *procstat_sysctl(void *, int, size_t, size_t *sizep);
static pid_t g_pid; /* Pid being dumped, global for elf_detach */
+static int g_status; /* proc status after ptrace attach */
static int
elf_ident(int efd, pid_t pid __unused, char *binfile __unused)
@@ -159,9 +160,18 @@ elf_ident(int efd, pid_t pid __unused, c
static void
elf_detach(void)
{
+ int sig;
- if (g_pid != 0)
- ptrace(PT_DETACH, g_pid, (caddr_t)1, 0);
+ if (g_pid != 0) {
+ /*
+ * Forward any pending signals. SIGSTOP is generated by ptrace
+ * itself, so ignore it.
+ */
+ sig = WIFSTOPPED(g_status) ? WSTOPSIG(g_status) : 0;
+ if (sig == SIGSTOP)
+ sig = 0;
+ ptrace(PT_DETACH, g_pid, (caddr_t)1, sig);
+ }
}
/*
@@ -187,7 +197,7 @@ elf_coredump(int efd __unused, int fd, p
ptrace(PT_ATTACH, pid, NULL, 0);
if (errno)
err(1, "PT_ATTACH");
- if (waitpid(pid, NULL, 0) == -1)
+ if (waitpid(pid, &g_status, 0) == -1)
err(1, "waitpid");
/* Get the program's memory map. */
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