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authormarkj <markj@FreeBSD.org>2016-06-24 20:21:32 +0000
committermarkj <markj@FreeBSD.org>2016-06-24 20:21:32 +0000
commitc5064f0323016fc0ff3a8d674ba24995ac35c1e6 (patch)
tree3ca0d2a50c3cebd344e5b58baf5217223b3d87f8 /usr.bin
parent452fe84d9bb6b8ee9f4c237029a2d5db04aa41fe (diff)
downloadFreeBSD-src-c5064f0323016fc0ff3a8d674ba24995ac35c1e6.zip
FreeBSD-src-c5064f0323016fc0ff3a8d674ba24995ac35c1e6.tar.gz
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@isilon.com> Reviewed by: bdrewery Approved by: re (gjb, kib) MFC after: 2 weeks Sponsored by: EMC / Isilon Storage Division
Diffstat (limited to 'usr.bin')
-rw-r--r--usr.bin/gcore/elfcore.c16
1 files changed, 13 insertions, 3 deletions
diff --git a/usr.bin/gcore/elfcore.c b/usr.bin/gcore/elfcore.c
index c96e3ae..98c9024 100644
--- a/usr.bin/gcore/elfcore.c
+++ b/usr.bin/gcore/elfcore.c
@@ -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, char *binfile __unused)
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, pid_t pid)
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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