Merge pull request #10244 from poettering/nofile-bump

bump RLIMIT_NOFILE

src/basic/def.h

@@ -75,3 +75,5 @@
                 _CONF_PATHS_SPLIT_USR(n))
 
 #define LONG_LINE_MAX (1U*1024U*1024U)
+
+#define HIGH_RLIMIT_MEMLOCK (1024ULL*1024ULL*64ULL)

src/basic/rlimit-util.c

@@ -5,6 +5,7 @@
 
 #include "alloc-util.h"
 #include "extract-word.h"
+#include "fd-util.h"
 #include "format-util.h"
 #include "macro.h"
 #include "missing.h"
@@ -33,8 +34,15 @@ int setrlimit_closest(int resource, const struct rlimit *rlim) {
         if (highest.rlim_max == RLIM_INFINITY)
                 return -EPERM;
 
-        fixed.rlim_cur = MIN(rlim->rlim_cur, highest.rlim_max);
-        fixed.rlim_max = MIN(rlim->rlim_max, highest.rlim_max);
+        fixed = (struct rlimit) {
+                .rlim_cur = MIN(rlim->rlim_cur, highest.rlim_max),
+                .rlim_max = MIN(rlim->rlim_max, highest.rlim_max),
+        };
+
+        /* Shortcut things if we wouldn't change anything. */
+        if (fixed.rlim_cur == highest.rlim_cur &&
+            fixed.rlim_max == highest.rlim_max)
+                return 0;
 
         if (setrlimit(resource, &fixed) < 0)
                 return -errno;
@@ -360,3 +368,24 @@ void rlimit_free_all(struct rlimit **rl) {
         for (i = 0; i < _RLIMIT_MAX; i++)
                 rl[i] = mfree(rl[i]);
 }
+
+int rlimit_nofile_bump(int limit) {
+        int r;
+
+        /* Bumps the (soft) RLIMIT_NOFILE resource limit as close as possible to the specified limit. If a negative
+         * limit is specified, bumps it to the maximum the kernel and the hard resource limit allows. This call should
+         * be used by all our programs that might need a lot of fds, and that know how to deal with high fd numbers
+         * (i.e. do not use select() — which chokes on fds >= 1024) */
+
+        if (limit < 0)
+                limit = read_nr_open();
+
+        if (limit < 3)
+                limit = 3;
+
+        r = setrlimit_closest(RLIMIT_NOFILE, &RLIMIT_MAKE_CONST(limit));
+        if (r < 0)
+                return log_debug_errno(r, "Failed to set RLIMIT_NOFILE: %m");
+
+        return 0;
+}

src/basic/rlimit-util.h

@@ -20,3 +20,5 @@ int rlimit_format(const struct rlimit *rl, char **ret);
 void rlimit_free_all(struct rlimit **rl);
 
 #define RLIMIT_MAKE_CONST(lim) ((struct rlimit) { lim, lim })
+
+int rlimit_nofile_bump(int limit);