From 5a46d55fc8f3dc4a86f3994f96369d169c0b96bb Mon Sep 17 00:00:00 2001 From: Zbigniew Jędrzejewski-Szmek Date: Sun, 2 Oct 2016 15:51:27 +0200 Subject: path-util: add a function to peek into a container and guess systemd version This is a bit crude and only works for new systemd versions which have libsystemd-shared. --- src/basic/path-util.c | 68 +++++++++++++++++++++++++++++++++++++++++++++++ src/basic/path-util.h | 2 ++ src/test/test-path-util.c | 19 +++++++++++++ 3 files changed, 89 insertions(+) diff --git a/src/basic/path-util.c b/src/basic/path-util.c index b2fa81a294..c32e961af4 100644 --- a/src/basic/path-util.c +++ b/src/basic/path-util.c @@ -34,9 +34,11 @@ #include "alloc-util.h" #include "extract-word.h" #include "fs-util.h" +#include "glob-util.h" #include "log.h" #include "macro.h" #include "missing.h" +#include "parse-util.h" #include "path-util.h" #include "stat-util.h" #include "string-util.h" @@ -814,3 +816,69 @@ bool is_device_path(const char *path) { path_startswith(path, "/dev/") || path_startswith(path, "/sys/"); } + +int systemd_installation_has_version(const char *root, unsigned minimal_version) { + const char *pattern; + int r; + + /* Try to guess if systemd installation is later than the specified version. This + * is hacky and likely to yield false negatives, particularly if the installation + * is non-standard. False positives should be relatively rare. + */ + + NULSTR_FOREACH(pattern, + /* /lib works for systems without usr-merge, and for systems with a sane + * usr-merge, where /lib is a symlink to /usr/lib. /usr/lib is necessary + * for Gentoo which does a merge without making /lib a symlink. + */ + "lib/systemd/libsystemd-shared-*.so\0" + "usr/lib/systemd/libsystemd-shared-*.so\0") { + + _cleanup_strv_free_ char **names = NULL; + _cleanup_free_ char *path = NULL; + char *c, **name; + + path = prefix_root(root, pattern); + if (!path) + return -ENOMEM; + + r = glob_extend(&names, path); + if (r == -ENOENT) + continue; + if (r < 0) + return r; + + assert_se((c = endswith(path, "*.so"))); + *c = '\0'; /* truncate the glob part */ + + STRV_FOREACH(name, names) { + /* This is most likely to run only once, hence let's not optimize anything. */ + char *t, *t2; + unsigned version; + + t = startswith(*name, path); + if (!t) + continue; + + t2 = endswith(t, ".so"); + if (!t2) + continue; + + t2[0] = '\0'; /* truncate the suffix */ + + r = safe_atou(t, &version); + if (r < 0) { + log_debug_errno(r, "Found libsystemd shared at \"%s.so\", but failed to parse version: %m", *name); + continue; + } + + log_debug("Found libsystemd shared at \"%s.so\", version %u (%s).", + *name, version, + version >= minimal_version ? "OK" : "too old"); + if (version >= minimal_version) + return true; + } + } + + return false; +} diff --git a/src/basic/path-util.h b/src/basic/path-util.h index a27c13fcc3..78472f0961 100644 --- a/src/basic/path-util.h +++ b/src/basic/path-util.h @@ -125,3 +125,5 @@ char *file_in_same_dir(const char *path, const char *filename); bool hidden_or_backup_file(const char *filename) _pure_; bool is_device_path(const char *path); + +int systemd_installation_has_version(const char *root, unsigned minimal_version); diff --git a/src/test/test-path-util.c b/src/test/test-path-util.c index 164a10d8a8..0b10d8e25e 100644 --- a/src/test/test-path-util.c +++ b/src/test/test-path-util.c @@ -511,7 +511,24 @@ static void test_hidden_or_backup_file(void) { assert_se(!hidden_or_backup_file("test.dpkg-old.foo")); } +static void test_systemd_installation_has_version(const char *path) { + int r; + const unsigned versions[] = {0, 231, atoi(PACKAGE_VERSION), 999}; + unsigned i; + + for (i = 0; i < ELEMENTSOF(versions); i++) { + r = systemd_installation_has_version(path, versions[i]); + assert_se(r >= 0); + log_info("%s has systemd >= %u: %s", + path ?: "Current installation", versions[i], yes_no(r)); + } +} + int main(int argc, char **argv) { + log_set_max_level(LOG_DEBUG); + log_parse_environment(); + log_open(); + test_path(); test_find_binary(argv[0]); test_prefixes(); @@ -526,5 +543,7 @@ int main(int argc, char **argv) { test_filename_is_valid(); test_hidden_or_backup_file(); + test_systemd_installation_has_version(argv[1]); /* NULL is OK */ + return 0; } -- cgit v1.2.3-54-g00ecf