From cda7faa9a5ae2fa1ebc27b08e84d5ce62e46e37b Mon Sep 17 00:00:00 2001 From: Lennart Poettering Date: Wed, 16 Jan 2019 18:05:14 +0100 Subject: [PATCH] main: don't bump resource limits if they are higher than we need them anyway This matters in particular in the case of --user, since there we lack the privs to bump the limits up again later on when invoking children. --- src/core/main.c | 34 ++++++++++++++++++++++++++++++++-- 1 file changed, 32 insertions(+), 2 deletions(-) diff --git a/src/core/main.c b/src/core/main.c index 3a87c29..1b81542 100644 --- a/src/core/main.c +++ b/src/core/main.c @@ -1269,6 +1269,7 @@ static void bump_file_max_and_nr_open(void) { } static int bump_rlimit_nofile(struct rlimit *saved_rlimit) { + struct rlimit new_rlimit; int r, nr; assert(saved_rlimit); @@ -1306,9 +1307,22 @@ static int bump_rlimit_nofile(struct rlimit *saved_rlimit) { arg_default_rlimit[RLIMIT_NOFILE] = rl; } + /* Calculate the new limits to use for us. Never lower from what we inherited. */ + new_rlimit = (struct rlimit) { + .rlim_cur = MAX((rlim_t) nr, saved_rlimit->rlim_cur), + .rlim_max = MAX((rlim_t) nr, saved_rlimit->rlim_max), + }; + + /* Shortcut if nothing changes. */ + if (saved_rlimit->rlim_max >= new_rlimit.rlim_max && + saved_rlimit->rlim_cur >= new_rlimit.rlim_cur) { + log_debug("RLIMIT_NOFILE is already as high or higher than we need it, not bumping."); + return 0; + } + /* Bump up the resource limit for ourselves substantially, all the way to the maximum the kernel allows, for * both hard and soft. */ - r = setrlimit_closest(RLIMIT_NOFILE, &RLIMIT_MAKE_CONST(nr)); + r = setrlimit_closest(RLIMIT_NOFILE, &new_rlimit); if (r < 0) return log_warning_errno(r, "Setting RLIMIT_NOFILE failed, ignoring: %m"); @@ -1316,6 +1330,7 @@ static int bump_rlimit_nofile(struct rlimit *saved_rlimit) { } static int bump_rlimit_memlock(struct rlimit *saved_rlimit) { + struct rlimit new_rlimit; int r; assert(saved_rlimit); @@ -1338,7 +1353,22 @@ static int bump_rlimit_memlock(struct rlimit *saved_rlimit) { arg_default_rlimit[RLIMIT_MEMLOCK] = rl; } - r = setrlimit_closest(RLIMIT_MEMLOCK, &RLIMIT_MAKE_CONST(HIGH_RLIMIT_MEMLOCK)); + /* Using MAX() on resource limits only is safe if RLIM_INFINITY is > 0. POSIX declares that rlim_t + * must be unsigned, hence this is a given, but let's make this clear here. */ + assert_cc(RLIM_INFINITY > 0); + + new_rlimit = (struct rlimit) { + .rlim_cur = MAX(HIGH_RLIMIT_MEMLOCK, saved_rlimit->rlim_cur), + .rlim_max = MAX(HIGH_RLIMIT_MEMLOCK, saved_rlimit->rlim_max), + }; + + if (saved_rlimit->rlim_max >= new_rlimit.rlim_cur && + saved_rlimit->rlim_cur >= new_rlimit.rlim_max) { + log_debug("RLIMIT_MEMLOCK is already as high or higher than we need it, not bumping."); + return 0; + } + + r = setrlimit_closest(RLIMIT_MEMLOCK, &new_rlimit); if (r < 0) return log_warning_errno(r, "Setting RLIMIT_MEMLOCK failed, ignoring: %m"); -- 2.7.4