From c43ef2e8836a497cedc3a06e6f0aebe484bf688a Mon Sep 17 00:00:00 2001
From: Ryan Wilson <ryantimwilson@meta.com>
Date: Wed, 16 Oct 2024 10:40:30 -0700
Subject: [PATCH] oomd: Refactor DefaultMemoryPressureDurationSec= to use conf
 parser

Parsing DefaultMemoryPressureDurationSec= is currently split between
conf parser, main() and manager_start() methods. This commit centralizes
parsing and bounds checking logic within a single custom conf parser
function.
---
 src/oom/oomd-manager.c |  2 +-
 src/oom/oomd.c         | 44 +++++++++++++++++++++++++++++++++++++-----
 2 files changed, 40 insertions(+), 6 deletions(-)

diff --git a/src/oom/oomd-manager.c b/src/oom/oomd-manager.c
index 33e9f288b41..6d1b4f024b2 100644
--- a/src/oom/oomd-manager.c
+++ b/src/oom/oomd-manager.c
@@ -770,7 +770,7 @@ int manager_start(
         if (r < 0)
                 return r;
 
-        m->default_mem_pressure_duration_usec = mem_pressure_usec ?: DEFAULT_MEM_PRESSURE_DURATION_USEC;
+        m->default_mem_pressure_duration_usec = mem_pressure_usec;
 
         r = manager_connect_bus(m);
         if (r < 0)
diff --git a/src/oom/oomd.c b/src/oom/oomd.c
index 336549aff7d..dd34251cd24 100644
--- a/src/oom/oomd.c
+++ b/src/oom/oomd.c
@@ -21,13 +21,50 @@
 static bool arg_dry_run = false;
 static int arg_swap_used_limit_permyriad = -1;
 static int arg_mem_pressure_limit_permyriad = -1;
-static usec_t arg_mem_pressure_usec = 0;
+static usec_t arg_mem_pressure_usec = DEFAULT_MEM_PRESSURE_DURATION_USEC;
+
+static int config_parse_duration(
+                const char *unit,
+                const char *filename,
+                unsigned line,
+                const char *section,
+                unsigned section_line,
+                const char *lvalue,
+                int ltype,
+                const char *rvalue,
+                void *data,
+                void *userdata) {
+
+        usec_t usec, *duration = ASSERT_PTR(data);
+        int r;
+
+        if (isempty(rvalue)) {
+                *duration = DEFAULT_MEM_PRESSURE_DURATION_USEC;
+                return 0;
+        }
+
+        r = parse_sec(rvalue, &usec);
+        if (r < 0)
+                return log_syntax_parse_error(unit, filename, line, r, lvalue, rvalue);
+
+        if (usec == 0) {
+                /* Map zero -> default for backwards compatibility. */
+                *duration = DEFAULT_MEM_PRESSURE_DURATION_USEC;
+                return 0;
+        }
+
+        if (usec < 1 * USEC_PER_SEC || usec == USEC_INFINITY)
+                return log_syntax(unit, LOG_WARNING, filename, line, 0, "%s= must be at least 1s and less than infinity, ignoring: %s", lvalue, rvalue);
+
+        *duration = usec;
+        return 0;
+}
 
 static int parse_config(void) {
         static const ConfigTableItem items[] = {
                 { "OOM", "SwapUsedLimit",                    config_parse_permyriad, 0, &arg_swap_used_limit_permyriad    },
                 { "OOM", "DefaultMemoryPressureLimit",       config_parse_permyriad, 0, &arg_mem_pressure_limit_permyriad },
-                { "OOM", "DefaultMemoryPressureDurationSec", config_parse_sec,       0, &arg_mem_pressure_usec            },
+                { "OOM", "DefaultMemoryPressureDurationSec", config_parse_duration,  0, &arg_mem_pressure_usec            },
                 {}
         };
 
@@ -167,9 +204,6 @@ static int run(int argc, char *argv[]) {
         if (!FLAGS_SET(mask, CGROUP_MASK_MEMORY))
                 return log_error_errno(SYNTHETIC_ERRNO(EOPNOTSUPP), "Requires the cgroup memory controller.");
 
-        if (arg_mem_pressure_usec > 0 && arg_mem_pressure_usec < 1 * USEC_PER_SEC)
-                return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "DefaultMemoryPressureDurationSec= must be 0 or at least 1s");
-
         r = manager_new(&m);
         if (r < 0)
                 return log_error_errno(r, "Failed to create manager: %m");
-- 
2.47.3