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-rw-r--r--src/basic/fileio.c1436
1 files changed, 1436 insertions, 0 deletions
diff --git a/src/basic/fileio.c b/src/basic/fileio.c
new file mode 100644
index 0000000..2c4ba89
--- /dev/null
+++ b/src/basic/fileio.c
@@ -0,0 +1,1436 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <ctype.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <limits.h>
+#include <stdarg.h>
+#include <stdint.h>
+#include <stdio_ext.h>
+#include <stdlib.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include "alloc-util.h"
+#include "chase-symlinks.h"
+#include "fd-util.h"
+#include "fileio.h"
+#include "fs-util.h"
+#include "hexdecoct.h"
+#include "log.h"
+#include "macro.h"
+#include "mkdir.h"
+#include "parse-util.h"
+#include "path-util.h"
+#include "socket-util.h"
+#include "stdio-util.h"
+#include "string-util.h"
+#include "sync-util.h"
+#include "tmpfile-util.h"
+
+/* The maximum size of the file we'll read in one go in read_full_file() (64M). */
+#define READ_FULL_BYTES_MAX (64U*1024U*1024U - 1U)
+
+/* The maximum size of virtual files (i.e. procfs, sysfs, and other virtual "API" files) we'll read in one go
+ * in read_virtual_file(). Note that this limit is different (and much lower) than the READ_FULL_BYTES_MAX
+ * limit. This reflects the fact that we use different strategies for reading virtual and regular files:
+ * virtual files we generally have to read in a single read() syscall since the kernel doesn't support
+ * continuation read()s for them. Thankfully they are somewhat size constrained. Thus we can allocate the
+ * full potential buffer in advance. Regular files OTOH can be much larger, and there we grow the allocations
+ * exponentially in a loop. We use a size limit of 4M-2 because 4M-1 is the maximum buffer that /proc/sys/
+ * allows us to read() (larger reads will fail with ENOMEM), and we want to read one extra byte so that we
+ * can detect EOFs. */
+#define READ_VIRTUAL_BYTES_MAX (4U*1024U*1024U - 2U)
+
+int fopen_unlocked(const char *path, const char *options, FILE **ret) {
+ assert(ret);
+
+ FILE *f = fopen(path, options);
+ if (!f)
+ return -errno;
+
+ (void) __fsetlocking(f, FSETLOCKING_BYCALLER);
+
+ *ret = f;
+ return 0;
+}
+
+int fdopen_unlocked(int fd, const char *options, FILE **ret) {
+ assert(ret);
+
+ FILE *f = fdopen(fd, options);
+ if (!f)
+ return -errno;
+
+ (void) __fsetlocking(f, FSETLOCKING_BYCALLER);
+
+ *ret = f;
+ return 0;
+}
+
+int take_fdopen_unlocked(int *fd, const char *options, FILE **ret) {
+ int r;
+
+ assert(fd);
+
+ r = fdopen_unlocked(*fd, options, ret);
+ if (r < 0)
+ return r;
+
+ *fd = -1;
+
+ return 0;
+}
+
+FILE* take_fdopen(int *fd, const char *options) {
+ assert(fd);
+
+ FILE *f = fdopen(*fd, options);
+ if (!f)
+ return NULL;
+
+ *fd = -1;
+
+ return f;
+}
+
+DIR* take_fdopendir(int *dfd) {
+ assert(dfd);
+
+ DIR *d = fdopendir(*dfd);
+ if (!d)
+ return NULL;
+
+ *dfd = -1;
+
+ return d;
+}
+
+FILE* open_memstream_unlocked(char **ptr, size_t *sizeloc) {
+ FILE *f = open_memstream(ptr, sizeloc);
+ if (!f)
+ return NULL;
+
+ (void) __fsetlocking(f, FSETLOCKING_BYCALLER);
+
+ return f;
+}
+
+FILE* fmemopen_unlocked(void *buf, size_t size, const char *mode) {
+ FILE *f = fmemopen(buf, size, mode);
+ if (!f)
+ return NULL;
+
+ (void) __fsetlocking(f, FSETLOCKING_BYCALLER);
+
+ return f;
+}
+
+int write_string_stream_ts(
+ FILE *f,
+ const char *line,
+ WriteStringFileFlags flags,
+ const struct timespec *ts) {
+
+ bool needs_nl;
+ int r, fd = -1;
+
+ assert(f);
+ assert(line);
+
+ if (ferror(f))
+ return -EIO;
+
+ if (ts) {
+ /* If we shall set the timestamp we need the fd. But fmemopen() streams generally don't have
+ * an fd. Let's fail early in that case. */
+ fd = fileno(f);
+ if (fd < 0)
+ return -EBADF;
+ }
+
+ if (flags & WRITE_STRING_FILE_SUPPRESS_REDUNDANT_VIRTUAL) {
+ _cleanup_free_ char *t = NULL;
+
+ /* If value to be written is same as that of the existing value, then suppress the write. */
+
+ if (fd < 0) {
+ fd = fileno(f);
+ if (fd < 0)
+ return -EBADF;
+ }
+
+ /* Read an additional byte to detect cases where the prefix matches but the rest
+ * doesn't. Also, 0 returned by read_virtual_file_fd() means the read was truncated and
+ * it won't be equal to the new value. */
+ if (read_virtual_file_fd(fd, strlen(line)+1, &t, NULL) > 0 &&
+ streq_skip_trailing_chars(line, t, NEWLINE)) {
+ log_debug("No change in value '%s', suppressing write", line);
+ return 0;
+ }
+
+ if (lseek(fd, 0, SEEK_SET) < 0)
+ return -errno;
+ }
+
+ needs_nl = !(flags & WRITE_STRING_FILE_AVOID_NEWLINE) && !endswith(line, "\n");
+
+ if (needs_nl && (flags & WRITE_STRING_FILE_DISABLE_BUFFER)) {
+ /* If STDIO buffering was disabled, then let's append the newline character to the string
+ * itself, so that the write goes out in one go, instead of two */
+
+ line = strjoina(line, "\n");
+ needs_nl = false;
+ }
+
+ if (fputs(line, f) == EOF)
+ return -errno;
+
+ if (needs_nl)
+ if (fputc('\n', f) == EOF)
+ return -errno;
+
+ if (flags & WRITE_STRING_FILE_SYNC)
+ r = fflush_sync_and_check(f);
+ else
+ r = fflush_and_check(f);
+ if (r < 0)
+ return r;
+
+ if (ts) {
+ const struct timespec twice[2] = {*ts, *ts};
+
+ assert(fd >= 0);
+ if (futimens(fd, twice) < 0)
+ return -errno;
+ }
+
+ return 0;
+}
+
+static int write_string_file_atomic(
+ const char *fn,
+ const char *line,
+ WriteStringFileFlags flags,
+ const struct timespec *ts) {
+
+ _cleanup_fclose_ FILE *f = NULL;
+ _cleanup_free_ char *p = NULL;
+ int r;
+
+ assert(fn);
+ assert(line);
+
+ /* Note that we'd really like to use O_TMPFILE here, but can't really, since we want replacement
+ * semantics here, and O_TMPFILE can't offer that. i.e. rename() replaces but linkat() doesn't. */
+
+ r = fopen_temporary(fn, &f, &p);
+ if (r < 0)
+ return r;
+
+ r = write_string_stream_ts(f, line, flags, ts);
+ if (r < 0)
+ goto fail;
+
+ r = fchmod_umask(fileno(f), FLAGS_SET(flags, WRITE_STRING_FILE_MODE_0600) ? 0600 : 0644);
+ if (r < 0)
+ goto fail;
+
+ if (rename(p, fn) < 0) {
+ r = -errno;
+ goto fail;
+ }
+
+ if (FLAGS_SET(flags, WRITE_STRING_FILE_SYNC)) {
+ /* Sync the rename, too */
+ r = fsync_directory_of_file(fileno(f));
+ if (r < 0)
+ return r;
+ }
+
+ return 0;
+
+fail:
+ (void) unlink(p);
+ return r;
+}
+
+int write_string_file_ts(
+ const char *fn,
+ const char *line,
+ WriteStringFileFlags flags,
+ const struct timespec *ts) {
+
+ _cleanup_fclose_ FILE *f = NULL;
+ int q, r, fd;
+
+ assert(fn);
+ assert(line);
+
+ /* We don't know how to verify whether the file contents was already on-disk. */
+ assert(!((flags & WRITE_STRING_FILE_VERIFY_ON_FAILURE) && (flags & WRITE_STRING_FILE_SYNC)));
+
+ if (flags & WRITE_STRING_FILE_MKDIR_0755) {
+ r = mkdir_parents(fn, 0755);
+ if (r < 0)
+ return r;
+ }
+
+ if (flags & WRITE_STRING_FILE_ATOMIC) {
+ assert(flags & WRITE_STRING_FILE_CREATE);
+
+ r = write_string_file_atomic(fn, line, flags, ts);
+ if (r < 0)
+ goto fail;
+
+ return r;
+ } else
+ assert(!ts);
+
+ /* We manually build our own version of fopen(..., "we") that works without O_CREAT and with O_NOFOLLOW if needed. */
+ fd = open(fn, O_CLOEXEC|O_NOCTTY |
+ (FLAGS_SET(flags, WRITE_STRING_FILE_NOFOLLOW) ? O_NOFOLLOW : 0) |
+ (FLAGS_SET(flags, WRITE_STRING_FILE_CREATE) ? O_CREAT : 0) |
+ (FLAGS_SET(flags, WRITE_STRING_FILE_TRUNCATE) ? O_TRUNC : 0) |
+ (FLAGS_SET(flags, WRITE_STRING_FILE_SUPPRESS_REDUNDANT_VIRTUAL) ? O_RDWR : O_WRONLY),
+ (FLAGS_SET(flags, WRITE_STRING_FILE_MODE_0600) ? 0600 : 0666));
+ if (fd < 0) {
+ r = -errno;
+ goto fail;
+ }
+
+ r = fdopen_unlocked(fd, "w", &f);
+ if (r < 0) {
+ safe_close(fd);
+ goto fail;
+ }
+
+ if (flags & WRITE_STRING_FILE_DISABLE_BUFFER)
+ setvbuf(f, NULL, _IONBF, 0);
+
+ r = write_string_stream_ts(f, line, flags, ts);
+ if (r < 0)
+ goto fail;
+
+ return 0;
+
+fail:
+ if (!(flags & WRITE_STRING_FILE_VERIFY_ON_FAILURE))
+ return r;
+
+ f = safe_fclose(f);
+
+ /* OK, the operation failed, but let's see if the right
+ * contents in place already. If so, eat up the error. */
+
+ q = verify_file(fn, line, !(flags & WRITE_STRING_FILE_AVOID_NEWLINE) || (flags & WRITE_STRING_FILE_VERIFY_IGNORE_NEWLINE));
+ if (q <= 0)
+ return r;
+
+ return 0;
+}
+
+int write_string_filef(
+ const char *fn,
+ WriteStringFileFlags flags,
+ const char *format, ...) {
+
+ _cleanup_free_ char *p = NULL;
+ va_list ap;
+ int r;
+
+ va_start(ap, format);
+ r = vasprintf(&p, format, ap);
+ va_end(ap);
+
+ if (r < 0)
+ return -ENOMEM;
+
+ return write_string_file(fn, p, flags);
+}
+
+int read_one_line_file(const char *fn, char **line) {
+ _cleanup_fclose_ FILE *f = NULL;
+ int r;
+
+ assert(fn);
+ assert(line);
+
+ r = fopen_unlocked(fn, "re", &f);
+ if (r < 0)
+ return r;
+
+ return read_line(f, LONG_LINE_MAX, line);
+}
+
+int verify_file(const char *fn, const char *blob, bool accept_extra_nl) {
+ _cleanup_fclose_ FILE *f = NULL;
+ _cleanup_free_ char *buf = NULL;
+ size_t l, k;
+ int r;
+
+ assert(fn);
+ assert(blob);
+
+ l = strlen(blob);
+
+ if (accept_extra_nl && endswith(blob, "\n"))
+ accept_extra_nl = false;
+
+ buf = malloc(l + accept_extra_nl + 1);
+ if (!buf)
+ return -ENOMEM;
+
+ r = fopen_unlocked(fn, "re", &f);
+ if (r < 0)
+ return r;
+
+ /* We try to read one byte more than we need, so that we know whether we hit eof */
+ errno = 0;
+ k = fread(buf, 1, l + accept_extra_nl + 1, f);
+ if (ferror(f))
+ return errno_or_else(EIO);
+
+ if (k != l && k != l + accept_extra_nl)
+ return 0;
+ if (memcmp(buf, blob, l) != 0)
+ return 0;
+ if (k > l && buf[l] != '\n')
+ return 0;
+
+ return 1;
+}
+
+int read_virtual_file_fd(int fd, size_t max_size, char **ret_contents, size_t *ret_size) {
+ _cleanup_free_ char *buf = NULL;
+ size_t n, size;
+ int n_retries;
+ bool truncated = false;
+
+ /* Virtual filesystems such as sysfs or procfs use kernfs, and kernfs can work with two sorts of
+ * virtual files. One sort uses "seq_file", and the results of the first read are buffered for the
+ * second read. The other sort uses "raw" reads which always go direct to the device. In the latter
+ * case, the content of the virtual file must be retrieved with a single read otherwise a second read
+ * might get the new value instead of finding EOF immediately. That's the reason why the usage of
+ * fread(3) is prohibited in this case as it always performs a second call to read(2) looking for
+ * EOF. See issue #13585.
+ *
+ * max_size specifies a limit on the bytes read. If max_size is SIZE_MAX, the full file is read. If
+ * the full file is too large to read, an error is returned. For other values of max_size, *partial
+ * contents* may be returned. (Though the read is still done using one syscall.) Returns 0 on
+ * partial success, 1 if untruncated contents were read. */
+
+ assert(fd >= 0);
+ assert(max_size <= READ_VIRTUAL_BYTES_MAX || max_size == SIZE_MAX);
+
+ /* Limit the number of attempts to read the number of bytes returned by fstat(). */
+ n_retries = 3;
+
+ for (;;) {
+ struct stat st;
+
+ if (fstat(fd, &st) < 0)
+ return -errno;
+
+ if (!S_ISREG(st.st_mode))
+ return -EBADF;
+
+ /* Be prepared for files from /proc which generally report a file size of 0. */
+ assert_cc(READ_VIRTUAL_BYTES_MAX < SSIZE_MAX);
+ if (st.st_size > 0 && n_retries > 1) {
+ /* Let's use the file size if we have more than 1 attempt left. On the last attempt
+ * we'll ignore the file size */
+
+ if (st.st_size > SSIZE_MAX) { /* Avoid overflow with 32-bit size_t and 64-bit off_t. */
+
+ if (max_size == SIZE_MAX)
+ return -EFBIG;
+
+ size = max_size;
+ } else {
+ size = MIN((size_t) st.st_size, max_size);
+
+ if (size > READ_VIRTUAL_BYTES_MAX)
+ return -EFBIG;
+ }
+
+ n_retries--;
+ } else if (n_retries > 1) {
+ /* Files in /proc are generally smaller than the page size so let's start with
+ * a page size buffer from malloc and only use the max buffer on the final try. */
+ size = MIN3(page_size() - 1, READ_VIRTUAL_BYTES_MAX, max_size);
+ n_retries = 1;
+ } else {
+ size = MIN(READ_VIRTUAL_BYTES_MAX, max_size);
+ n_retries = 0;
+ }
+
+ buf = malloc(size + 1);
+ if (!buf)
+ return -ENOMEM;
+
+ /* Use a bigger allocation if we got it anyway, but not more than the limit. */
+ size = MIN3(MALLOC_SIZEOF_SAFE(buf) - 1, max_size, READ_VIRTUAL_BYTES_MAX);
+
+ for (;;) {
+ ssize_t k;
+
+ /* Read one more byte so we can detect whether the content of the
+ * file has already changed or the guessed size for files from /proc
+ * wasn't large enough . */
+ k = read(fd, buf, size + 1);
+ if (k >= 0) {
+ n = k;
+ break;
+ }
+
+ if (errno != EINTR)
+ return -errno;
+ }
+
+ /* Consider a short read as EOF */
+ if (n <= size)
+ break;
+
+ /* If a maximum size is specified and we already read more we know the file is larger, and
+ * can handle this as truncation case. Note that if the size of what we read equals the
+ * maximum size then this doesn't mean truncation, the file might or might not end on that
+ * byte. We need to rerun the loop in that case, with a larger buffer size, so that we read
+ * at least one more byte to be able to distinguish EOF from truncation. */
+ if (max_size != SIZE_MAX && n > max_size) {
+ n = size; /* Make sure we never use more than what we sized the buffer for (so that
+ * we have one free byte in it for the trailing NUL we add below).*/
+ truncated = true;
+ break;
+ }
+
+ /* We have no further attempts left? Then the file is apparently larger than our limits. Give up. */
+ if (n_retries <= 0)
+ return -EFBIG;
+
+ /* Hmm... either we read too few bytes from /proc or less likely the content of the file
+ * might have been changed (and is now bigger) while we were processing, let's try again
+ * either with the new file size. */
+
+ if (lseek(fd, 0, SEEK_SET) < 0)
+ return -errno;
+
+ buf = mfree(buf);
+ }
+
+ if (ret_contents) {
+
+ /* Safety check: if the caller doesn't want to know the size of what we just read it will
+ * rely on the trailing NUL byte. But if there's an embedded NUL byte, then we should refuse
+ * operation as otherwise there'd be ambiguity about what we just read. */
+ if (!ret_size && memchr(buf, 0, n))
+ return -EBADMSG;
+
+ if (n < size) {
+ char *p;
+
+ /* Return rest of the buffer to libc */
+ p = realloc(buf, n + 1);
+ if (!p)
+ return -ENOMEM;
+ buf = p;
+ }
+
+ buf[n] = 0;
+ *ret_contents = TAKE_PTR(buf);
+ }
+
+ if (ret_size)
+ *ret_size = n;
+
+ return !truncated;
+}
+
+int read_virtual_file_at(
+ int dir_fd,
+ const char *filename,
+ size_t max_size,
+ char **ret_contents,
+ size_t *ret_size) {
+
+ _cleanup_close_ int fd = -1;
+
+ assert(dir_fd >= 0 || dir_fd == AT_FDCWD);
+
+ if (!filename) {
+ if (dir_fd == AT_FDCWD)
+ return -EBADF;
+
+ return read_virtual_file_fd(dir_fd, max_size, ret_contents, ret_size);
+ }
+
+ fd = openat(dir_fd, filename, O_RDONLY | O_NOCTTY | O_CLOEXEC);
+ if (fd < 0)
+ return -errno;
+
+ return read_virtual_file_fd(fd, max_size, ret_contents, ret_size);
+}
+
+int read_full_stream_full(
+ FILE *f,
+ const char *filename,
+ uint64_t offset,
+ size_t size,
+ ReadFullFileFlags flags,
+ char **ret_contents,
+ size_t *ret_size) {
+
+ _cleanup_free_ char *buf = NULL;
+ size_t n, n_next = 0, l;
+ int fd, r;
+
+ assert(f);
+ assert(ret_contents);
+ assert(!FLAGS_SET(flags, READ_FULL_FILE_UNBASE64 | READ_FULL_FILE_UNHEX));
+ assert(size != SIZE_MAX || !FLAGS_SET(flags, READ_FULL_FILE_FAIL_WHEN_LARGER));
+
+ if (offset != UINT64_MAX && offset > LONG_MAX) /* fseek() can only deal with "long" offsets */
+ return -ERANGE;
+
+ fd = fileno(f);
+ if (fd >= 0) { /* If the FILE* object is backed by an fd (as opposed to memory or such, see
+ * fmemopen()), let's optimize our buffering */
+ struct stat st;
+
+ if (fstat(fd, &st) < 0)
+ return -errno;
+
+ if (S_ISREG(st.st_mode)) {
+
+ /* Try to start with the right file size if we shall read the file in full. Note
+ * that we increase the size to read here by one, so that the first read attempt
+ * already makes us notice the EOF. If the reported size of the file is zero, we
+ * avoid this logic however, since quite likely it might be a virtual file in procfs
+ * that all report a zero file size. */
+
+ if (st.st_size > 0 &&
+ (size == SIZE_MAX || FLAGS_SET(flags, READ_FULL_FILE_FAIL_WHEN_LARGER))) {
+
+ uint64_t rsize =
+ LESS_BY((uint64_t) st.st_size, offset == UINT64_MAX ? 0 : offset);
+
+ if (rsize < SIZE_MAX) /* overflow check */
+ n_next = rsize + 1;
+ }
+
+ if (flags & READ_FULL_FILE_WARN_WORLD_READABLE)
+ (void) warn_file_is_world_accessible(filename, &st, NULL, 0);
+ }
+ }
+
+ /* If we don't know how much to read, figure it out now. If we shall read a part of the file, then
+ * allocate the requested size. If we shall load the full file start with LINE_MAX. Note that if
+ * READ_FULL_FILE_FAIL_WHEN_LARGER we consider the specified size a safety limit, and thus also start
+ * with LINE_MAX, under assumption the file is most likely much shorter. */
+ if (n_next == 0)
+ n_next = size != SIZE_MAX && !FLAGS_SET(flags, READ_FULL_FILE_FAIL_WHEN_LARGER) ? size : LINE_MAX;
+
+ /* Never read more than we need to determine that our own limit is hit */
+ if (n_next > READ_FULL_BYTES_MAX)
+ n_next = READ_FULL_BYTES_MAX + 1;
+
+ if (offset != UINT64_MAX && fseek(f, offset, SEEK_SET) < 0)
+ return -errno;
+
+ n = l = 0;
+ for (;;) {
+ char *t;
+ size_t k;
+
+ /* If we shall fail when reading overly large data, then read exactly one byte more than the
+ * specified size at max, since that'll tell us if there's anymore data beyond the limit*/
+ if (FLAGS_SET(flags, READ_FULL_FILE_FAIL_WHEN_LARGER) && n_next > size)
+ n_next = size + 1;
+
+ if (flags & READ_FULL_FILE_SECURE) {
+ t = malloc(n_next + 1);
+ if (!t) {
+ r = -ENOMEM;
+ goto finalize;
+ }
+ memcpy_safe(t, buf, n);
+ explicit_bzero_safe(buf, n);
+ free(buf);
+ } else {
+ t = realloc(buf, n_next + 1);
+ if (!t)
+ return -ENOMEM;
+ }
+
+ buf = t;
+ /* Unless a size has been explicitly specified, try to read as much as fits into the memory
+ * we allocated (minus 1, to leave one byte for the safety NUL byte) */
+ n = size == SIZE_MAX ? MALLOC_SIZEOF_SAFE(buf) - 1 : n_next;
+
+ errno = 0;
+ k = fread(buf + l, 1, n - l, f);
+
+ assert(k <= n - l);
+ l += k;
+
+ if (ferror(f)) {
+ r = errno_or_else(EIO);
+ goto finalize;
+ }
+ if (feof(f))
+ break;
+
+ if (size != SIZE_MAX && !FLAGS_SET(flags, READ_FULL_FILE_FAIL_WHEN_LARGER)) { /* If we got asked to read some specific size, we already sized the buffer right, hence leave */
+ assert(l == size);
+ break;
+ }
+
+ assert(k > 0); /* we can't have read zero bytes because that would have been EOF */
+
+ if (FLAGS_SET(flags, READ_FULL_FILE_FAIL_WHEN_LARGER) && l > size) {
+ r = -E2BIG;
+ goto finalize;
+ }
+
+ if (n >= READ_FULL_BYTES_MAX) {
+ r = -E2BIG;
+ goto finalize;
+ }
+
+ n_next = MIN(n * 2, READ_FULL_BYTES_MAX);
+ }
+
+ if (flags & (READ_FULL_FILE_UNBASE64 | READ_FULL_FILE_UNHEX)) {
+ _cleanup_free_ void *decoded = NULL;
+ size_t decoded_size;
+
+ buf[l++] = 0;
+ if (flags & READ_FULL_FILE_UNBASE64)
+ r = unbase64mem_full(buf, l, flags & READ_FULL_FILE_SECURE, &decoded, &decoded_size);
+ else
+ r = unhexmem_full(buf, l, flags & READ_FULL_FILE_SECURE, &decoded, &decoded_size);
+ if (r < 0)
+ goto finalize;
+
+ if (flags & READ_FULL_FILE_SECURE)
+ explicit_bzero_safe(buf, n);
+ free_and_replace(buf, decoded);
+ n = l = decoded_size;
+ }
+
+ if (!ret_size) {
+ /* Safety check: if the caller doesn't want to know the size of what we just read it will rely on the
+ * trailing NUL byte. But if there's an embedded NUL byte, then we should refuse operation as otherwise
+ * there'd be ambiguity about what we just read. */
+
+ if (memchr(buf, 0, l)) {
+ r = -EBADMSG;
+ goto finalize;
+ }
+ }
+
+ buf[l] = 0;
+ *ret_contents = TAKE_PTR(buf);
+
+ if (ret_size)
+ *ret_size = l;
+
+ return 0;
+
+finalize:
+ if (flags & READ_FULL_FILE_SECURE)
+ explicit_bzero_safe(buf, n);
+
+ return r;
+}
+
+int read_full_file_full(
+ int dir_fd,
+ const char *filename,
+ uint64_t offset,
+ size_t size,
+ ReadFullFileFlags flags,
+ const char *bind_name,
+ char **ret_contents,
+ size_t *ret_size) {
+
+ _cleanup_fclose_ FILE *f = NULL;
+ int r;
+
+ assert(filename);
+ assert(ret_contents);
+
+ r = xfopenat(dir_fd, filename, "re", 0, &f);
+ if (r < 0) {
+ _cleanup_close_ int sk = -1;
+
+ /* ENXIO is what Linux returns if we open a node that is an AF_UNIX socket */
+ if (r != -ENXIO)
+ return r;
+
+ /* If this is enabled, let's try to connect to it */
+ if (!FLAGS_SET(flags, READ_FULL_FILE_CONNECT_SOCKET))
+ return -ENXIO;
+
+ /* Seeking is not supported on AF_UNIX sockets */
+ if (offset != UINT64_MAX)
+ return -ENXIO;
+
+ sk = socket(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC, 0);
+ if (sk < 0)
+ return -errno;
+
+ if (bind_name) {
+ /* If the caller specified a socket name to bind to, do so before connecting. This is
+ * useful to communicate some minor, short meta-information token from the client to
+ * the server. */
+ union sockaddr_union bsa;
+
+ r = sockaddr_un_set_path(&bsa.un, bind_name);
+ if (r < 0)
+ return r;
+
+ if (bind(sk, &bsa.sa, r) < 0)
+ return -errno;
+ }
+
+ r = connect_unix_path(sk, dir_fd, filename);
+ if (IN_SET(r, -ENOTSOCK, -EINVAL)) /* propagate original error if this is not a socket after all */
+ return -ENXIO;
+ if (r < 0)
+ return r;
+
+ if (shutdown(sk, SHUT_WR) < 0)
+ return -errno;
+
+ f = fdopen(sk, "r");
+ if (!f)
+ return -errno;
+
+ TAKE_FD(sk);
+ }
+
+ (void) __fsetlocking(f, FSETLOCKING_BYCALLER);
+
+ return read_full_stream_full(f, filename, offset, size, flags, ret_contents, ret_size);
+}
+
+int executable_is_script(const char *path, char **interpreter) {
+ _cleanup_free_ char *line = NULL;
+ size_t len;
+ char *ans;
+ int r;
+
+ assert(path);
+
+ r = read_one_line_file(path, &line);
+ if (r == -ENOBUFS) /* First line overly long? if so, then it's not a script */
+ return 0;
+ if (r < 0)
+ return r;
+
+ if (!startswith(line, "#!"))
+ return 0;
+
+ ans = strstrip(line + 2);
+ len = strcspn(ans, " \t");
+
+ if (len == 0)
+ return 0;
+
+ ans = strndup(ans, len);
+ if (!ans)
+ return -ENOMEM;
+
+ *interpreter = ans;
+ return 1;
+}
+
+/**
+ * Retrieve one field from a file like /proc/self/status. pattern
+ * should not include whitespace or the delimiter (':'). pattern matches only
+ * the beginning of a line. Whitespace before ':' is skipped. Whitespace and
+ * zeros after the ':' will be skipped. field must be freed afterwards.
+ * terminator specifies the terminating characters of the field value (not
+ * included in the value).
+ */
+int get_proc_field(const char *filename, const char *pattern, const char *terminator, char **field) {
+ _cleanup_free_ char *status = NULL;
+ char *t, *f;
+ size_t len;
+ int r;
+
+ assert(terminator);
+ assert(filename);
+ assert(pattern);
+ assert(field);
+
+ r = read_full_virtual_file(filename, &status, NULL);
+ if (r < 0)
+ return r;
+
+ t = status;
+
+ do {
+ bool pattern_ok;
+
+ do {
+ t = strstr(t, pattern);
+ if (!t)
+ return -ENOENT;
+
+ /* Check that pattern occurs in beginning of line. */
+ pattern_ok = (t == status || t[-1] == '\n');
+
+ t += strlen(pattern);
+
+ } while (!pattern_ok);
+
+ t += strspn(t, " \t");
+ if (!*t)
+ return -ENOENT;
+
+ } while (*t != ':');
+
+ t++;
+
+ if (*t) {
+ t += strspn(t, " \t");
+
+ /* Also skip zeros, because when this is used for
+ * capabilities, we don't want the zeros. This way the
+ * same capability set always maps to the same string,
+ * irrespective of the total capability set size. For
+ * other numbers it shouldn't matter. */
+ t += strspn(t, "0");
+ /* Back off one char if there's nothing but whitespace
+ and zeros */
+ if (!*t || isspace(*t))
+ t--;
+ }
+
+ len = strcspn(t, terminator);
+
+ f = strndup(t, len);
+ if (!f)
+ return -ENOMEM;
+
+ *field = f;
+ return 0;
+}
+
+DIR *xopendirat(int fd, const char *name, int flags) {
+ int nfd;
+ DIR *d;
+
+ assert(!(flags & O_CREAT));
+
+ if (fd == AT_FDCWD && flags == 0)
+ return opendir(name);
+
+ nfd = openat(fd, name, O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC|flags, 0);
+ if (nfd < 0)
+ return NULL;
+
+ d = fdopendir(nfd);
+ if (!d) {
+ safe_close(nfd);
+ return NULL;
+ }
+
+ return d;
+}
+
+int fopen_mode_to_flags(const char *mode) {
+ const char *p;
+ int flags;
+
+ assert(mode);
+
+ if ((p = startswith(mode, "r+")))
+ flags = O_RDWR;
+ else if ((p = startswith(mode, "r")))
+ flags = O_RDONLY;
+ else if ((p = startswith(mode, "w+")))
+ flags = O_RDWR|O_CREAT|O_TRUNC;
+ else if ((p = startswith(mode, "w")))
+ flags = O_WRONLY|O_CREAT|O_TRUNC;
+ else if ((p = startswith(mode, "a+")))
+ flags = O_RDWR|O_CREAT|O_APPEND;
+ else if ((p = startswith(mode, "a")))
+ flags = O_WRONLY|O_CREAT|O_APPEND;
+ else
+ return -EINVAL;
+
+ for (; *p != 0; p++) {
+
+ switch (*p) {
+
+ case 'e':
+ flags |= O_CLOEXEC;
+ break;
+
+ case 'x':
+ flags |= O_EXCL;
+ break;
+
+ case 'm':
+ /* ignore this here, fdopen() might care later though */
+ break;
+
+ case 'c': /* not sure what to do about this one */
+ default:
+ return -EINVAL;
+ }
+ }
+
+ return flags;
+}
+
+int xfopenat(int dir_fd, const char *path, const char *mode, int flags, FILE **ret) {
+ FILE *f;
+
+ /* A combination of fopen() with openat() */
+
+ if (dir_fd == AT_FDCWD && flags == 0) {
+ f = fopen(path, mode);
+ if (!f)
+ return -errno;
+ } else {
+ int fd, mode_flags;
+
+ mode_flags = fopen_mode_to_flags(mode);
+ if (mode_flags < 0)
+ return mode_flags;
+
+ fd = openat(dir_fd, path, mode_flags | flags);
+ if (fd < 0)
+ return -errno;
+
+ f = fdopen(fd, mode);
+ if (!f) {
+ safe_close(fd);
+ return -errno;
+ }
+ }
+
+ *ret = f;
+ return 0;
+}
+
+static int search_and_fopen_internal(
+ const char *path,
+ const char *mode,
+ const char *root,
+ char **search,
+ FILE **ret,
+ char **ret_path) {
+
+ assert(path);
+ assert(mode);
+ assert(ret);
+
+ if (!path_strv_resolve_uniq(search, root))
+ return -ENOMEM;
+
+ STRV_FOREACH(i, search) {
+ _cleanup_free_ char *p = NULL;
+ FILE *f;
+
+ p = path_join(root, *i, path);
+ if (!p)
+ return -ENOMEM;
+
+ f = fopen(p, mode);
+ if (f) {
+ if (ret_path)
+ *ret_path = path_simplify(TAKE_PTR(p));
+
+ *ret = f;
+ return 0;
+ }
+
+ if (errno != ENOENT)
+ return -errno;
+ }
+
+ return -ENOENT;
+}
+
+int search_and_fopen(
+ const char *filename,
+ const char *mode,
+ const char *root,
+ const char **search,
+ FILE **ret,
+ char **ret_path) {
+
+ _cleanup_strv_free_ char **copy = NULL;
+
+ assert(filename);
+ assert(mode);
+ assert(ret);
+
+ if (path_is_absolute(filename)) {
+ _cleanup_fclose_ FILE *f = NULL;
+
+ f = fopen(filename, mode);
+ if (!f)
+ return -errno;
+
+ if (ret_path) {
+ char *p;
+
+ p = strdup(filename);
+ if (!p)
+ return -ENOMEM;
+
+ *ret_path = path_simplify(p);
+ }
+
+ *ret = TAKE_PTR(f);
+ return 0;
+ }
+
+ copy = strv_copy((char**) search);
+ if (!copy)
+ return -ENOMEM;
+
+ return search_and_fopen_internal(filename, mode, root, copy, ret, ret_path);
+}
+
+int search_and_fopen_nulstr(
+ const char *filename,
+ const char *mode,
+ const char *root,
+ const char *search,
+ FILE **ret,
+ char **ret_path) {
+
+ _cleanup_strv_free_ char **s = NULL;
+
+ if (path_is_absolute(filename)) {
+ _cleanup_fclose_ FILE *f = NULL;
+
+ f = fopen(filename, mode);
+ if (!f)
+ return -errno;
+
+ if (ret_path) {
+ char *p;
+
+ p = strdup(filename);
+ if (!p)
+ return -ENOMEM;
+
+ *ret_path = path_simplify(p);
+ }
+
+ *ret = TAKE_PTR(f);
+ return 0;
+ }
+
+ s = strv_split_nulstr(search);
+ if (!s)
+ return -ENOMEM;
+
+ return search_and_fopen_internal(filename, mode, root, s, ret, ret_path);
+}
+
+int fflush_and_check(FILE *f) {
+ assert(f);
+
+ errno = 0;
+ fflush(f);
+
+ if (ferror(f))
+ return errno_or_else(EIO);
+
+ return 0;
+}
+
+int fflush_sync_and_check(FILE *f) {
+ int r, fd;
+
+ assert(f);
+
+ r = fflush_and_check(f);
+ if (r < 0)
+ return r;
+
+ /* Not all file streams have an fd associated (think: fmemopen()), let's handle this gracefully and
+ * assume that in that case we need no explicit syncing */
+ fd = fileno(f);
+ if (fd < 0)
+ return 0;
+
+ r = fsync_full(fd);
+ if (r < 0)
+ return r;
+
+ return 0;
+}
+
+int write_timestamp_file_atomic(const char *fn, usec_t n) {
+ char ln[DECIMAL_STR_MAX(n)+2];
+
+ /* Creates a "timestamp" file, that contains nothing but a
+ * usec_t timestamp, formatted in ASCII. */
+
+ if (!timestamp_is_set(n))
+ return -ERANGE;
+
+ xsprintf(ln, USEC_FMT "\n", n);
+
+ return write_string_file(fn, ln, WRITE_STRING_FILE_CREATE|WRITE_STRING_FILE_ATOMIC);
+}
+
+int read_timestamp_file(const char *fn, usec_t *ret) {
+ _cleanup_free_ char *ln = NULL;
+ uint64_t t;
+ int r;
+
+ r = read_one_line_file(fn, &ln);
+ if (r < 0)
+ return r;
+
+ r = safe_atou64(ln, &t);
+ if (r < 0)
+ return r;
+
+ if (!timestamp_is_set(t))
+ return -ERANGE;
+
+ *ret = (usec_t) t;
+ return 0;
+}
+
+int fputs_with_space(FILE *f, const char *s, const char *separator, bool *space) {
+ int r;
+
+ assert(s);
+
+ /* Outputs the specified string with fputs(), but optionally prefixes it with a separator. The *space parameter
+ * when specified shall initially point to a boolean variable initialized to false. It is set to true after the
+ * first invocation. This call is supposed to be use in loops, where a separator shall be inserted between each
+ * element, but not before the first one. */
+
+ if (!f)
+ f = stdout;
+
+ if (space) {
+ if (!separator)
+ separator = " ";
+
+ if (*space) {
+ r = fputs(separator, f);
+ if (r < 0)
+ return r;
+ }
+
+ *space = true;
+ }
+
+ return fputs(s, f);
+}
+
+/* A bitmask of the EOL markers we know */
+typedef enum EndOfLineMarker {
+ EOL_NONE = 0,
+ EOL_ZERO = 1 << 0, /* \0 (aka NUL) */
+ EOL_TEN = 1 << 1, /* \n (aka NL, aka LF) */
+ EOL_THIRTEEN = 1 << 2, /* \r (aka CR) */
+} EndOfLineMarker;
+
+static EndOfLineMarker categorize_eol(char c, ReadLineFlags flags) {
+
+ if (!IN_SET(flags, READ_LINE_ONLY_NUL)) {
+ if (c == '\n')
+ return EOL_TEN;
+ if (c == '\r')
+ return EOL_THIRTEEN;
+ }
+
+ if (c == '\0')
+ return EOL_ZERO;
+
+ return EOL_NONE;
+}
+
+DEFINE_TRIVIAL_CLEANUP_FUNC_FULL(FILE*, funlockfile, NULL);
+
+int read_line_full(FILE *f, size_t limit, ReadLineFlags flags, char **ret) {
+ _cleanup_free_ char *buffer = NULL;
+ size_t n = 0, count = 0;
+ int r;
+
+ assert(f);
+
+ /* Something like a bounded version of getline().
+ *
+ * Considers EOF, \n, \r and \0 end of line delimiters (or combinations of these), and does not include these
+ * delimiters in the string returned. Specifically, recognizes the following combinations of markers as line
+ * endings:
+ *
+ * • \n (UNIX)
+ * • \r (old MacOS)
+ * • \0 (C strings)
+ * • \n\0
+ * • \r\0
+ * • \r\n (Windows)
+ * • \n\r
+ * • \r\n\0
+ * • \n\r\0
+ *
+ * Returns the number of bytes read from the files (i.e. including delimiters — this hence usually differs from
+ * the number of characters in the returned string). When EOF is hit, 0 is returned.
+ *
+ * The input parameter limit is the maximum numbers of characters in the returned string, i.e. excluding
+ * delimiters. If the limit is hit we fail and return -ENOBUFS.
+ *
+ * If a line shall be skipped ret may be initialized as NULL. */
+
+ if (ret) {
+ if (!GREEDY_REALLOC(buffer, 1))
+ return -ENOMEM;
+ }
+
+ {
+ _unused_ _cleanup_(funlockfilep) FILE *flocked = f;
+ EndOfLineMarker previous_eol = EOL_NONE;
+ flockfile(f);
+
+ for (;;) {
+ EndOfLineMarker eol;
+ char c;
+
+ if (n >= limit)
+ return -ENOBUFS;
+
+ if (count >= INT_MAX) /* We couldn't return the counter anymore as "int", hence refuse this */
+ return -ENOBUFS;
+
+ r = safe_fgetc(f, &c);
+ if (r < 0)
+ return r;
+ if (r == 0) /* EOF is definitely EOL */
+ break;
+
+ eol = categorize_eol(c, flags);
+
+ if (FLAGS_SET(previous_eol, EOL_ZERO) ||
+ (eol == EOL_NONE && previous_eol != EOL_NONE) ||
+ (eol != EOL_NONE && (previous_eol & eol) != 0)) {
+ /* Previous char was a NUL? This is not an EOL, but the previous char was? This type of
+ * EOL marker has been seen right before? In either of these three cases we are
+ * done. But first, let's put this character back in the queue. (Note that we have to
+ * cast this to (unsigned char) here as ungetc() expects a positive 'int', and if we
+ * are on an architecture where 'char' equals 'signed char' we need to ensure we don't
+ * pass a negative value here. That said, to complicate things further ungetc() is
+ * actually happy with most negative characters and implicitly casts them back to
+ * positive ones as needed, except for \xff (aka -1, aka EOF), which it refuses. What a
+ * godawful API!) */
+ assert_se(ungetc((unsigned char) c, f) != EOF);
+ break;
+ }
+
+ count++;
+
+ if (eol != EOL_NONE) {
+ /* If we are on a tty, we can't shouldn't wait for more input, because that
+ * generally means waiting for the user, interactively. In the case of a TTY
+ * we expect only \n as the single EOL marker, so we are in the lucky
+ * position that there is no need to wait. We check this condition last, to
+ * avoid isatty() check if not necessary. */
+
+ if ((flags & (READ_LINE_IS_A_TTY|READ_LINE_NOT_A_TTY)) == 0) {
+ int fd;
+
+ fd = fileno(f);
+ if (fd < 0) /* Maybe an fmemopen() stream? Handle this gracefully,
+ * and don't call isatty() on an invalid fd */
+ flags |= READ_LINE_NOT_A_TTY;
+ else
+ flags |= isatty(fd) ? READ_LINE_IS_A_TTY : READ_LINE_NOT_A_TTY;
+ }
+ if (FLAGS_SET(flags, READ_LINE_IS_A_TTY))
+ break;
+ }
+
+ if (eol != EOL_NONE) {
+ previous_eol |= eol;
+ continue;
+ }
+
+ if (ret) {
+ if (!GREEDY_REALLOC(buffer, n + 2))
+ return -ENOMEM;
+
+ buffer[n] = c;
+ }
+
+ n++;
+ }
+ }
+
+ if (ret) {
+ buffer[n] = 0;
+
+ *ret = TAKE_PTR(buffer);
+ }
+
+ return (int) count;
+}
+
+int safe_fgetc(FILE *f, char *ret) {
+ int k;
+
+ assert(f);
+
+ /* A safer version of plain fgetc(): let's propagate the error that happened while reading as such, and
+ * separate the EOF condition from the byte read, to avoid those confusion signed/unsigned issues fgetc()
+ * has. */
+
+ errno = 0;
+ k = fgetc(f);
+ if (k == EOF) {
+ if (ferror(f))
+ return errno_or_else(EIO);
+
+ if (ret)
+ *ret = 0;
+
+ return 0;
+ }
+
+ if (ret)
+ *ret = k;
+
+ return 1;
+}
+
+int warn_file_is_world_accessible(const char *filename, struct stat *st, const char *unit, unsigned line) {
+ struct stat _st;
+
+ if (!filename)
+ return 0;
+
+ if (!st) {
+ if (stat(filename, &_st) < 0)
+ return -errno;
+ st = &_st;
+ }
+
+ if ((st->st_mode & S_IRWXO) == 0)
+ return 0;
+
+ if (unit)
+ log_syntax(unit, LOG_WARNING, filename, line, 0,
+ "%s has %04o mode that is too permissive, please adjust the ownership and access mode.",
+ filename, st->st_mode & 07777);
+ else
+ log_warning("%s has %04o mode that is too permissive, please adjust the ownership and access mode.",
+ filename, st->st_mode & 07777);
+ return 0;
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-01 00:24:19 +0000