[Tarantool-patches] [PATCH 03/13] popen: add missed diag_set in popen_signal/delete
Alexander Turenko
alexander.turenko at tarantool.org
Fri Apr 10 05:50:41 MSK 2020
Lua API will use content of the diagnostics area to report an error to a
caller, so it is critical to always have proper diagnostics at failure.
Part of #4031
---
src/lib/core/popen.c | 37 +++++++++++++++++++++++++++----------
1 file changed, 27 insertions(+), 10 deletions(-)
diff --git a/src/lib/core/popen.c b/src/lib/core/popen.c
index 3a0ac4b53..3fcbc325a 100644
--- a/src/lib/core/popen.c
+++ b/src/lib/core/popen.c
@@ -164,16 +164,19 @@ popen_may_io(struct popen_handle *handle, unsigned int idx,
/**
* Test if the handle still have a living child process.
+ *
+ * Return -1 and set errno to ESRCH when a process does not
+ * exist. Otherwise return 0.
*/
-static inline bool
+static inline int
popen_may_pidop(struct popen_handle *handle)
{
assert(handle != NULL);
if (handle->pid == -1) {
errno = ESRCH;
- return false;
+ return -1;
}
- return true;
+ return 0;
}
/**
@@ -423,6 +426,10 @@ popen_state_str(unsigned int state)
/**
* Send a signal to a child process.
+ *
+ * Return 0 at success or -1 at failure (and set a diag).
+ *
+ * Set errno to ESRCH when a process does not exist.
*/
int
popen_send_signal(struct popen_handle *handle, int signo)
@@ -434,16 +441,22 @@ popen_send_signal(struct popen_handle *handle, int signo)
/*
* A child may be killed or exited already.
*/
- if (!popen_may_pidop(handle))
+ ret = popen_may_pidop(handle);
+ if (ret == 0) {
+ say_debug("popen: kill %d signo %d", handle->pid, signo);
+ assert(handle->pid != -1);
+ ret = kill(handle->pid, signo);
+ }
+ if (ret < 0 && errno == ESRCH) {
+ diag_set(SystemError, "Attempt to send a signal %d to a "
+ "process that does not exist anymore", signo);
return -1;
-
- say_debug("popen: kill %d signo %d", handle->pid, signo);
- ret = kill(handle->pid, signo);
- if (ret < 0) {
+ } else if (ret < 0) {
diag_set(SystemError, "Unable to kill %d signo %d",
handle->pid, signo);
+ return -1;
}
- return ret;
+ return 0;
}
/**
@@ -460,7 +473,11 @@ popen_delete(struct popen_handle *handle)
assert(handle != NULL);
- if (popen_send_signal(handle, SIGKILL) && errno != ESRCH)
+ /*
+ * Unable to kill the process -- give an error.
+ * The process is not exist already -- pass over.
+ */
+ if (popen_send_signal(handle, SIGKILL) != 0 && errno != ESRCH)
return -1;
for (i = 0; i < lengthof(handle->ios); i++) {
--
2.25.0
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