d284b82b3e
This doesn't have much effect on the final build, because we link libbasic.a
into libsystemd-shared.so, so in the end, all the object built from basic/
end up in libsystemd-shared. And when the static library is linked into binaries,
any objects that are included in it but are not used are trimmed. Hence, the
size of output artifacts doesn't change:
$ du -sb /var/tmp/inst*
54181861 /var/tmp/inst1 (old)
54207441 /var/tmp/inst1s (old split-usr)
54182477 /var/tmp/inst2 (new)
54208041 /var/tmp/inst2s (new split-usr)
(The negligible change in size is because libsystemd-shared.so is bigger
by a few hundred bytes. I guess it's because symbols are named differently
or something like that.)
The effect is on the build process, in particular partial builds. This change
effectively moves the requirements on some build steps toward the leaves of the
dependency tree. Two effects:
- when building items that do not depend on libsystemd-shared, we
build less stuff for libbasic.a (which wouldn't be used anyway,
so it's a net win).
- when building items that do depend on libshared, we reduce libbasic.a as a
synchronization point, possibly allowing better parallelism.
Method:
1. copy list of .h files from src/basic/meson.build to /tmp/basic
2. $ for i in $(grep '.h$' /tmp/basic); do echo $i; git --no-pager grep "include \"$i\"" src/basic/ 'src/lib*' 'src/nss-*' 'src/journal/sd-journal.c' |grep -v "${i%.h}.c";echo ;done | less
118 lines
3 KiB
C
118 lines
3 KiB
C
/* SPDX-License-Identifier: LGPL-2.1+ */
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#include "alloc-util.h"
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#include "fd-util.h"
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#include "fs-util.h"
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#include "macro.h"
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#include "os-util.h"
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#include "strv.h"
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#include "fileio.h"
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#include "string-util.h"
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int path_is_os_tree(const char *path) {
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int r;
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assert(path);
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/* Does the path exist at all? If not, generate an error immediately. This is useful so that a missing root dir
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* always results in -ENOENT, and we can properly distuingish the case where the whole root doesn't exist from
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* the case where just the os-release file is missing. */
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if (laccess(path, F_OK) < 0)
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return -errno;
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/* We use {/etc|/usr/lib}/os-release as flag file if something is an OS */
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r = open_os_release(path, NULL, NULL);
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if (r == -ENOENT) /* We got nothing */
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return 0;
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if (r < 0)
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return r;
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return 1;
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}
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int open_os_release(const char *root, char **ret_path, int *ret_fd) {
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_cleanup_free_ char *q = NULL;
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const char *p;
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int k;
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FOREACH_STRING(p, "/etc/os-release", "/usr/lib/os-release") {
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k = chase_symlinks(p, root, CHASE_PREFIX_ROOT|(ret_fd ? CHASE_OPEN : 0), (ret_path ? &q : NULL));
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if (k != -ENOENT)
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break;
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}
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if (k < 0)
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return k;
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if (ret_fd) {
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int real_fd;
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/* Convert the O_PATH fd into a proper, readable one */
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real_fd = fd_reopen(k, O_RDONLY|O_CLOEXEC|O_NOCTTY);
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safe_close(k);
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if (real_fd < 0)
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return real_fd;
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*ret_fd = real_fd;
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}
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if (ret_path)
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*ret_path = TAKE_PTR(q);
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return 0;
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}
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int fopen_os_release(const char *root, char **ret_path, FILE **ret_file) {
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_cleanup_free_ char *p = NULL;
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_cleanup_close_ int fd = -1;
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FILE *f;
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int r;
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if (!ret_file)
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return open_os_release(root, ret_path, NULL);
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r = open_os_release(root, ret_path ? &p : NULL, &fd);
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if (r < 0)
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return r;
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f = fdopen(fd, "re");
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if (!f)
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return -errno;
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fd = -1;
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*ret_file = f;
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if (ret_path)
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*ret_path = TAKE_PTR(p);
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return 0;
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}
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int parse_os_release(const char *root, ...) {
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_cleanup_fclose_ FILE *f = NULL;
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_cleanup_free_ char *p = NULL;
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va_list ap;
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int r;
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r = fopen_os_release(root, &p, &f);
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if (r < 0)
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return r;
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va_start(ap, root);
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r = parse_env_filev(f, p, ap);
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va_end(ap);
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return r;
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}
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int load_os_release_pairs(const char *root, char ***ret) {
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_cleanup_fclose_ FILE *f = NULL;
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_cleanup_free_ char *p = NULL;
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int r;
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r = fopen_os_release(root, &p, &f);
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if (r < 0)
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return r;
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return load_env_file_pairs(f, p, ret);
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}
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