<p>neels has uploaded this change for <strong>review</strong>.</p><p><a href="https://gerrit.osmocom.org/c/libosmocore/+/24544">View Change</a></p><pre style="font-family: monospace,monospace; white-space: pre-wrap;">osmo_select_shutdown: allow finishing pending writes on sigterm<br><br>So far various osmo programs have a curious sleep of two seconds upon<br>receiving SIGTERM. The idea presumably was to finish off pending writes<br>before halting the program. But a sleep(2) on program exit is annoying,<br>especially when there usually are no pending writes, and when osmo-bsc<br>is launched numerous times for tests.<br><br>Allow running osmo_select_main* to only service pending writes.<br>Introduce a global boolean flag to indicate a shutdown request, and a<br>second boolean flag to indicate shutdown is complete.<br><br>Change-Id: Ib94d4316924103459577087c2214188679db2227<br>---<br>M include/osmocom/core/select.h<br>M src/select.c<br>2 files changed, 47 insertions(+), 1 deletion(-)<br><br></pre><pre style="font-family: monospace,monospace; white-space: pre-wrap;">git pull ssh://gerrit.osmocom.org:29418/libosmocore refs/changes/44/24544/1</pre><pre style="font-family: monospace,monospace; white-space: pre-wrap;"><span>diff --git a/include/osmocom/core/select.h b/include/osmocom/core/select.h</span><br><span>index b410199..11742da 100644</span><br><span>--- a/include/osmocom/core/select.h</span><br><span>+++ b/include/osmocom/core/select.h</span><br><span>@@ -27,6 +27,9 @@</span><br><span> #define BSC_FD_WRITE OSMO_FD_WRITE</span><br><span> #define BSC_FD_EXCEPT OSMO_FD_EXCEPT</span><br><span> </span><br><span style="color: hsl(120, 100%, 40%);">+extern bool osmo_select_shutdown;</span><br><span style="color: hsl(120, 100%, 40%);">+extern bool osmo_select_shutdown_done;</span><br><span style="color: hsl(120, 100%, 40%);">+</span><br><span> /*! Structure representing a file dsecriptor */</span><br><span> struct osmo_fd {</span><br><span> /*! linked list for internal management */</span><br><span>diff --git a/src/select.c b/src/select.c</span><br><span>index 71ee7f6..e3bbbb0 100644</span><br><span>--- a/src/select.c</span><br><span>+++ b/src/select.c</span><br><span>@@ -69,6 +69,39 @@</span><br><span> static __thread struct poll_state g_poll;</span><br><span> #endif /* FORCE_IO_SELECT */</span><br><span> </span><br><span style="color: hsl(120, 100%, 40%);">+/*! A calling main program may request osmo_select_* to only service pending OSMO_FD_WRITE requests. Once all writes are</span><br><span style="color: hsl(120, 100%, 40%);">+ * done, osmo_select_shutdown_done is set to true. This allows for example to send all outbound packets before</span><br><span style="color: hsl(120, 100%, 40%);">+ * terminating the process.</span><br><span style="color: hsl(120, 100%, 40%);">+ *</span><br><span style="color: hsl(120, 100%, 40%);">+ * Usage example:</span><br><span style="color: hsl(120, 100%, 40%);">+ *</span><br><span style="color: hsl(120, 100%, 40%);">+ * static void signal_handler(int signum)</span><br><span style="color: hsl(120, 100%, 40%);">+ * {</span><br><span style="color: hsl(120, 100%, 40%);">+ * fprintf(stdout, "signal %u received\n", signum);</span><br><span style="color: hsl(120, 100%, 40%);">+ *</span><br><span style="color: hsl(120, 100%, 40%);">+ * switch (signum) {</span><br><span style="color: hsl(120, 100%, 40%);">+ * case SIGINT:</span><br><span style="color: hsl(120, 100%, 40%);">+ * case SIGTERM:</span><br><span style="color: hsl(120, 100%, 40%);">+ * // If SIGTERM was already sent before, just terminate immediately this time around.</span><br><span style="color: hsl(120, 100%, 40%);">+ * if (osmo_select_shutdown)</span><br><span style="color: hsl(120, 100%, 40%);">+ * exit(-1);</span><br><span style="color: hsl(120, 100%, 40%);">+ * osmo_select_shutdown = true;</span><br><span style="color: hsl(120, 100%, 40%);">+ * break;</span><br><span style="color: hsl(120, 100%, 40%);">+ * [...]</span><br><span style="color: hsl(120, 100%, 40%);">+ * }</span><br><span style="color: hsl(120, 100%, 40%);">+ *</span><br><span style="color: hsl(120, 100%, 40%);">+ * main()</span><br><span style="color: hsl(120, 100%, 40%);">+ * {</span><br><span style="color: hsl(120, 100%, 40%);">+ * [...]</span><br><span style="color: hsl(120, 100%, 40%);">+ * while (!osmo_select_shutdown_done) {</span><br><span style="color: hsl(120, 100%, 40%);">+ * osmo_select_main_ctx(0);</span><br><span style="color: hsl(120, 100%, 40%);">+ * }</span><br><span style="color: hsl(120, 100%, 40%);">+ * }</span><br><span style="color: hsl(120, 100%, 40%);">+ */</span><br><span style="color: hsl(120, 100%, 40%);">+bool osmo_select_shutdown = false;</span><br><span style="color: hsl(120, 100%, 40%);">+/*! Set to true when osmo_select_shutdown is true and osmo_select's poll loop found no pending write operations. */</span><br><span style="color: hsl(120, 100%, 40%);">+bool osmo_select_shutdown_done = false;</span><br><span style="color: hsl(120, 100%, 40%);">+</span><br><span> /*! Set up an osmo-fd. Will not register it.</span><br><span> * \param[inout] ofd Osmo FD to be set-up</span><br><span> * \param[in] fd OS-level file descriptor number</span><br><span>@@ -316,6 +349,7 @@</span><br><span> struct osmo_fd *ufd;</span><br><span> unsigned int i;</span><br><span> int work = 0;</span><br><span style="color: hsl(120, 100%, 40%);">+ int shutdown_pending_writes = 0;</span><br><span> </span><br><span> for (i = 0; i < n_fd; i++) {</span><br><span> struct pollfd *p = &g_poll.poll[i];</span><br><span>@@ -340,6 +374,11 @@</span><br><span> /* make sure we never report more than the user requested */</span><br><span> flags &= ufd->when;</span><br><span> </span><br><span style="color: hsl(120, 100%, 40%);">+ if (osmo_select_shutdown) {</span><br><span style="color: hsl(120, 100%, 40%);">+ if (ufd->when & OSMO_FD_WRITE)</span><br><span style="color: hsl(120, 100%, 40%);">+ shutdown_pending_writes++;</span><br><span style="color: hsl(120, 100%, 40%);">+ }</span><br><span style="color: hsl(120, 100%, 40%);">+</span><br><span> if (flags) {</span><br><span> work = 1;</span><br><span> /* make sure to clear any log context before processing the next incoming message</span><br><span>@@ -351,6 +390,9 @@</span><br><span> }</span><br><span> }</span><br><span> </span><br><span style="color: hsl(120, 100%, 40%);">+ if (osmo_select_shutdown && !shutdown_pending_writes)</span><br><span style="color: hsl(120, 100%, 40%);">+ osmo_select_shutdown_done = true;</span><br><span style="color: hsl(120, 100%, 40%);">+</span><br><span> return work;</span><br><span> }</span><br><span> </span><br><span>@@ -370,7 +412,8 @@</span><br><span> return 0;</span><br><span> </span><br><span> /* fire timers */</span><br><span style="color: hsl(0, 100%, 40%);">- osmo_timers_update();</span><br><span style="color: hsl(120, 100%, 40%);">+ if (!osmo_select_shutdown)</span><br><span style="color: hsl(120, 100%, 40%);">+ osmo_timers_update();</span><br><span> </span><br><span> OSMO_ASSERT(osmo_ctx->select);</span><br><span> </span><br><span></span><br></pre><p>To view, visit <a href="https://gerrit.osmocom.org/c/libosmocore/+/24544">change 24544</a>. 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<div style="display:none"> Gerrit-Project: libosmocore </div>
<div style="display:none"> Gerrit-Branch: master </div>
<div style="display:none"> Gerrit-Change-Id: Ib94d4316924103459577087c2214188679db2227 </div>
<div style="display:none"> Gerrit-Change-Number: 24544 </div>
<div style="display:none"> Gerrit-PatchSet: 1 </div>
<div style="display:none"> Gerrit-Owner: neels <nhofmeyr@sysmocom.de> </div>
<div style="display:none"> Gerrit-MessageType: newchange </div>