diff options
Diffstat (limited to 'shared/systemd/src/basic/tmpfile-util.c')
| -rw-r--r-- | shared/systemd/src/basic/tmpfile-util.c | 336 |
1 files changed, 336 insertions, 0 deletions
diff --git a/shared/systemd/src/basic/tmpfile-util.c b/shared/systemd/src/basic/tmpfile-util.c new file mode 100644 index 00000000..019121cb --- /dev/null +++ b/shared/systemd/src/basic/tmpfile-util.c @@ -0,0 +1,336 @@ +/* SPDX-License-Identifier: LGPL-2.1+ */ + +#include "nm-sd-adapt-shared.h" + +#include <sys/mman.h> + +#include "alloc-util.h" +#include "fd-util.h" +#include "fs-util.h" +#include "hexdecoct.h" +#include "macro.h" +#include "memfd-util.h" +#include "missing_fcntl.h" +#include "missing_syscall.h" +#include "path-util.h" +#include "process-util.h" +#include "random-util.h" +#include "stdio-util.h" +#include "string-util.h" +#include "tmpfile-util.h" +#include "umask-util.h" + +int fopen_temporary(const char *path, FILE **_f, char **_temp_path) { + FILE *f; + char *t; + int r, fd; + + assert(path); + assert(_f); + assert(_temp_path); + + r = tempfn_xxxxxx(path, NULL, &t); + if (r < 0) + return r; + + fd = mkostemp_safe(t); + if (fd < 0) { + free(t); + return -errno; + } + + f = fdopen(fd, "w"); + if (!f) { + unlink_noerrno(t); + free(t); + safe_close(fd); + return -errno; + } + + *_f = f; + *_temp_path = t; + + return 0; +} + +/* This is much like mkostemp() but is subject to umask(). */ +int mkostemp_safe(char *pattern) { + _cleanup_umask_ mode_t u = 0; + int fd; + + assert(pattern); + + u = umask(077); + + fd = mkostemp(pattern, O_CLOEXEC); + if (fd < 0) + return -errno; + + return fd; +} + +#if 0 /* NM_IGNORED */ +int fmkostemp_safe(char *pattern, const char *mode, FILE **ret_f) { + int fd; + FILE *f; + + fd = mkostemp_safe(pattern); + if (fd < 0) + return fd; + + f = fdopen(fd, mode); + if (!f) { + safe_close(fd); + return -errno; + } + + *ret_f = f; + return 0; +} +#endif /* NM_IGNORED */ + +int tempfn_xxxxxx(const char *p, const char *extra, char **ret) { + const char *fn; + char *t; + + assert(ret); + + if (isempty(p)) + return -EINVAL; + if (path_equal(p, "/")) + return -EINVAL; + + /* + * Turns this: + * /foo/bar/waldo + * + * Into this: + * /foo/bar/.#<extra>waldoXXXXXX + */ + + fn = basename(p); + if (!filename_is_valid(fn)) + return -EINVAL; + + extra = strempty(extra); + + t = new(char, strlen(p) + 2 + strlen(extra) + 6 + 1); + if (!t) + return -ENOMEM; + + strcpy(stpcpy(stpcpy(stpcpy(mempcpy(t, p, fn - p), ".#"), extra), fn), "XXXXXX"); + + *ret = path_simplify(t, false); + return 0; +} + +#if 0 /* NM_IGNORED */ +int tempfn_random(const char *p, const char *extra, char **ret) { + const char *fn; + char *t, *x; + uint64_t u; + unsigned i; + + assert(ret); + + if (isempty(p)) + return -EINVAL; + if (path_equal(p, "/")) + return -EINVAL; + + /* + * Turns this: + * /foo/bar/waldo + * + * Into this: + * /foo/bar/.#<extra>waldobaa2a261115984a9 + */ + + fn = basename(p); + if (!filename_is_valid(fn)) + return -EINVAL; + + extra = strempty(extra); + + t = new(char, strlen(p) + 2 + strlen(extra) + 16 + 1); + if (!t) + return -ENOMEM; + + x = stpcpy(stpcpy(stpcpy(mempcpy(t, p, fn - p), ".#"), extra), fn); + + u = random_u64(); + for (i = 0; i < 16; i++) { + *(x++) = hexchar(u & 0xF); + u >>= 4; + } + + *x = 0; + + *ret = path_simplify(t, false); + return 0; +} + +int tempfn_random_child(const char *p, const char *extra, char **ret) { + char *t, *x; + uint64_t u; + unsigned i; + int r; + + assert(ret); + + /* Turns this: + * /foo/bar/waldo + * Into this: + * /foo/bar/waldo/.#<extra>3c2b6219aa75d7d0 + */ + + if (!p) { + r = tmp_dir(&p); + if (r < 0) + return r; + } + + extra = strempty(extra); + + t = new(char, strlen(p) + 3 + strlen(extra) + 16 + 1); + if (!t) + return -ENOMEM; + + if (isempty(p)) + x = stpcpy(stpcpy(t, ".#"), extra); + else + x = stpcpy(stpcpy(stpcpy(t, p), "/.#"), extra); + + u = random_u64(); + for (i = 0; i < 16; i++) { + *(x++) = hexchar(u & 0xF); + u >>= 4; + } + + *x = 0; + + *ret = path_simplify(t, false); + return 0; +} + +int open_tmpfile_unlinkable(const char *directory, int flags) { + char *p; + int fd, r; + + if (!directory) { + r = tmp_dir(&directory); + if (r < 0) + return r; + } else if (isempty(directory)) + return -EINVAL; + + /* Returns an unlinked temporary file that cannot be linked into the file system anymore */ + + /* Try O_TMPFILE first, if it is supported */ + fd = open(directory, flags|O_TMPFILE|O_EXCL, S_IRUSR|S_IWUSR); + if (fd >= 0) + return fd; + + /* Fall back to unguessable name + unlinking */ + p = strjoina(directory, "/systemd-tmp-XXXXXX"); + + fd = mkostemp_safe(p); + if (fd < 0) + return fd; + + (void) unlink(p); + + return fd; +} + +int open_tmpfile_linkable(const char *target, int flags, char **ret_path) { + _cleanup_free_ char *tmp = NULL; + int r, fd; + + assert(target); + assert(ret_path); + + /* Don't allow O_EXCL, as that has a special meaning for O_TMPFILE */ + assert((flags & O_EXCL) == 0); + + /* Creates a temporary file, that shall be renamed to "target" later. If possible, this uses O_TMPFILE – in + * which case "ret_path" will be returned as NULL. If not possible a the tempoary path name used is returned in + * "ret_path". Use link_tmpfile() below to rename the result after writing the file in full. */ + + fd = open_parent(target, O_TMPFILE|flags, 0640); + if (fd >= 0) { + *ret_path = NULL; + return fd; + } + + log_debug_errno(fd, "Failed to use O_TMPFILE for %s: %m", target); + + r = tempfn_random(target, NULL, &tmp); + if (r < 0) + return r; + + fd = open(tmp, O_CREAT|O_EXCL|O_NOFOLLOW|O_NOCTTY|flags, 0640); + if (fd < 0) + return -errno; + + *ret_path = TAKE_PTR(tmp); + + return fd; +} + +int link_tmpfile(int fd, const char *path, const char *target) { + int r; + + assert(fd >= 0); + assert(target); + + /* Moves a temporary file created with open_tmpfile() above into its final place. if "path" is NULL an fd + * created with O_TMPFILE is assumed, and linkat() is used. Otherwise it is assumed O_TMPFILE is not supported + * on the directory, and renameat2() is used instead. + * + * Note that in both cases we will not replace existing files. This is because linkat() does not support this + * operation currently (renameat2() does), and there is no nice way to emulate this. */ + + if (path) { + r = rename_noreplace(AT_FDCWD, path, AT_FDCWD, target); + if (r < 0) + return r; + } else { + char proc_fd_path[STRLEN("/proc/self/fd/") + DECIMAL_STR_MAX(fd) + 1]; + + xsprintf(proc_fd_path, "/proc/self/fd/%i", fd); + + if (linkat(AT_FDCWD, proc_fd_path, AT_FDCWD, target, AT_SYMLINK_FOLLOW) < 0) + return -errno; + } + + return 0; +} + +int mkdtemp_malloc(const char *template, char **ret) { + _cleanup_free_ char *p = NULL; + int r; + + assert(ret); + + if (template) + p = strdup(template); + else { + const char *tmp; + + r = tmp_dir(&tmp); + if (r < 0) + return r; + + p = strjoin(tmp, "/XXXXXX"); + } + if (!p) + return -ENOMEM; + + if (!mkdtemp(p)) + return -errno; + + *ret = TAKE_PTR(p); + return 0; +} +#endif /* NM_IGNORED */ |