/* SPDX-License-Identifier: LGPL-2.1+ */ #include #include #include #include #include #include #include #include #include #include #include #include #include "alloc-util.h" #include "fd-util.h" #include "fileio.h" #include "fs-util.h" #include "log.h" #include "macro.h" #include "missing.h" #include "parse-util.h" #include "path-util.h" #include "stdio-util.h" #include "string-util.h" #include "tmpfile-util.h" #define READ_FULL_BYTES_MAX (4U*1024U*1024U) int write_string_stream_ts( FILE *f, const char *line, WriteStringFileFlags flags, struct timespec *ts) { bool needs_nl; int r; assert(f); assert(line); if (ferror(f)) return -EIO; 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) { struct timespec twice[2] = {*ts, *ts}; if (futimens(fileno(f), twice) < 0) return -errno; } return 0; } static int write_string_file_atomic( const char *fn, const char *line, WriteStringFileFlags flags, struct timespec *ts) { _cleanup_fclose_ FILE *f = NULL; _cleanup_free_ char *p = NULL; int r; assert(fn); assert(line); r = fopen_temporary(fn, &f, &p); if (r < 0) return r; (void) __fsetlocking(f, FSETLOCKING_BYCALLER); (void) fchmod_umask(fileno(f), 0644); r = write_string_stream_ts(f, line, flags, ts); if (r < 0) goto fail; if (rename(p, fn) < 0) { r = -errno; goto fail; } return 0; fail: (void) unlink(p); return r; } int write_string_file_ts( const char *fn, const char *line, WriteStringFileFlags flags, struct timespec *ts) { _cleanup_fclose_ FILE *f = NULL; int q, r; 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_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); if (flags & WRITE_STRING_FILE_CREATE) { f = fopen(fn, "we"); if (!f) { r = -errno; goto fail; } } else { int fd; /* We manually build our own version of fopen(..., "we") that * works without O_CREAT */ fd = open(fn, O_WRONLY|O_CLOEXEC|O_NOCTTY | ((flags & WRITE_STRING_FILE_NOFOLLOW) ? O_NOFOLLOW : 0)); if (fd < 0) { r = -errno; goto fail; } f = fdopen(fd, "w"); if (!f) { r = -errno; safe_close(fd); goto fail; } } (void) __fsetlocking(f, FSETLOCKING_BYCALLER); 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)); 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; assert(fn); assert(line); f = fopen(fn, "re"); if (!f) return -errno; (void) __fsetlocking(f, FSETLOCKING_BYCALLER); 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; 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; f = fopen(fn, "re"); if (!f) return -errno; (void) __fsetlocking(f, FSETLOCKING_BYCALLER); /* 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 > 0 ? -errno : -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_full_stream( FILE *f, char **ret_contents, size_t *ret_size) { _cleanup_free_ char *buf = NULL; struct stat st; size_t n, l; int fd; assert(f); assert(ret_contents); n = LINE_MAX; /* Start size */ 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) */ if (fstat(fileno(f), &st) < 0) return -errno; if (S_ISREG(st.st_mode)) { /* Safety check */ if (st.st_size > READ_FULL_BYTES_MAX) return -E2BIG; /* Start with the right file size, but be prepared for files from /proc which generally report a file * size of 0. Note that we increase the size to read here by one, so that the first read attempt * already makes us notice the EOF. */ if (st.st_size > 0) n = st.st_size + 1; } } l = 0; for (;;) { char *t; size_t k; t = realloc(buf, n + 1); if (!t) return -ENOMEM; buf = t; errno = 0; k = fread(buf + l, 1, n - l, f); if (k > 0) l += k; if (ferror(f)) return errno > 0 ? -errno : -EIO; if (feof(f)) break; /* We aren't expecting fread() to return a short read outside * of (error && eof), assert buffer is full and enlarge buffer. */ assert(l == n); /* Safety check */ if (n >= READ_FULL_BYTES_MAX) return -E2BIG; n = MIN(n * 2, READ_FULL_BYTES_MAX); } 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)) return -EBADMSG; } buf[l] = 0; *ret_contents = TAKE_PTR(buf); if (ret_size) *ret_size = l; return 0; } int read_full_file(const char *fn, char **contents, size_t *size) { _cleanup_fclose_ FILE *f = NULL; assert(fn); assert(contents); f = fopen(fn, "re"); if (!f) return -errno; (void) __fsetlocking(f, FSETLOCKING_BYCALLER); return read_full_stream(f, contents, 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_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)); 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; } static int search_and_fopen_internal(const char *path, const char *mode, const char *root, char **search, FILE **_f) { char **i; assert(path); assert(mode); assert(_f); if (!path_strv_resolve_uniq(search, root)) return -ENOMEM; STRV_FOREACH(i, search) { _cleanup_free_ char *p = NULL; FILE *f; if (root) p = strjoin(root, *i, "/", path); else p = strjoin(*i, "/", path); if (!p) return -ENOMEM; f = fopen(p, mode); if (f) { *_f = f; return 0; } if (errno != ENOENT) return -errno; } return -ENOENT; } int search_and_fopen(const char *path, const char *mode, const char *root, const char **search, FILE **_f) { _cleanup_strv_free_ char **copy = NULL; assert(path); assert(mode); assert(_f); if (path_is_absolute(path)) { FILE *f; f = fopen(path, mode); if (f) { *_f = f; return 0; } return -errno; } copy = strv_copy((char**) search); if (!copy) return -ENOMEM; return search_and_fopen_internal(path, mode, root, copy, _f); } int search_and_fopen_nulstr(const char *path, const char *mode, const char *root, const char *search, FILE **_f) { _cleanup_strv_free_ char **s = NULL; if (path_is_absolute(path)) { FILE *f; f = fopen(path, mode); if (f) { *_f = f; return 0; } return -errno; } s = strv_split_nulstr(search); if (!s) return -ENOMEM; return search_and_fopen_internal(path, mode, root, s, _f); } int fflush_and_check(FILE *f) { assert(f); errno = 0; fflush(f); if (ferror(f)) return errno > 0 ? -errno : -EIO; return 0; } int fflush_sync_and_check(FILE *f) { int r; assert(f); r = fflush_and_check(f); if (r < 0) return r; if (fsync(fileno(f)) < 0) return -errno; r = fsync_directory_of_file(fileno(f)); 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 (n <= 0 || n >= USEC_INFINITY) 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 (t <= 0 || t >= (uint64_t) USEC_INFINITY) 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(FILE*, funlockfile); int read_line_full(FILE *f, size_t limit, ReadLineFlags flags, char **ret) { size_t n = 0, allocated = 0, count = 0; _cleanup_free_ char *buffer = NULL; 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, allocated, 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) { previous_eol |= eol; continue; } if (ret) { if (!GREEDY_REALLOC(buffer, allocated, 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 > 0 ? -errno : -EIO; if (ret) *ret = 0; return 0; } if (ret) *ret = k; return 1; }