Chris Down
e92aaed30e
fdopen doesn't accept "e", it's ignored. Let's not mislead people into believing that it actually sets O_CLOEXEC. From `man 3 fdopen`: > e (since glibc 2.7): > Open the file with the O_CLOEXEC flag. See open(2) for more information. This flag is ignored for fdopen() As mentioned by @jlebon in #11131.
767 lines
20 KiB
C
767 lines
20 KiB
C
/* SPDX-License-Identifier: LGPL-2.1+ */
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#include <ctype.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <limits.h>
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#include <stdarg.h>
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#include <stdint.h>
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#include <stdio_ext.h>
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#include <stdlib.h>
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#include <string.h>
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#include <sys/stat.h>
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#include <sys/types.h>
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#include <unistd.h>
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#include "alloc-util.h"
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#include "fd-util.h"
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#include "fileio.h"
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#include "fs-util.h"
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#include "log.h"
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#include "macro.h"
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#include "missing.h"
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#include "parse-util.h"
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#include "path-util.h"
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#include "stdio-util.h"
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#include "string-util.h"
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#include "tmpfile-util.h"
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#define READ_FULL_BYTES_MAX (4U*1024U*1024U)
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int write_string_stream_ts(
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FILE *f,
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const char *line,
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WriteStringFileFlags flags,
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struct timespec *ts) {
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bool needs_nl;
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int r;
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assert(f);
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assert(line);
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if (ferror(f))
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return -EIO;
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needs_nl = !(flags & WRITE_STRING_FILE_AVOID_NEWLINE) && !endswith(line, "\n");
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if (needs_nl && (flags & WRITE_STRING_FILE_DISABLE_BUFFER)) {
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/* If STDIO buffering was disabled, then let's append the newline character to the string itself, so
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* that the write goes out in one go, instead of two */
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line = strjoina(line, "\n");
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needs_nl = false;
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}
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if (fputs(line, f) == EOF)
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return -errno;
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if (needs_nl)
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if (fputc('\n', f) == EOF)
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return -errno;
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if (flags & WRITE_STRING_FILE_SYNC)
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r = fflush_sync_and_check(f);
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else
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r = fflush_and_check(f);
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if (r < 0)
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return r;
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if (ts) {
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struct timespec twice[2] = {*ts, *ts};
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if (futimens(fileno(f), twice) < 0)
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return -errno;
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}
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return 0;
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}
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static int write_string_file_atomic(
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const char *fn,
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const char *line,
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WriteStringFileFlags flags,
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struct timespec *ts) {
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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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assert(fn);
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assert(line);
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r = fopen_temporary(fn, &f, &p);
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if (r < 0)
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return r;
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(void) __fsetlocking(f, FSETLOCKING_BYCALLER);
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(void) fchmod_umask(fileno(f), 0644);
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r = write_string_stream_ts(f, line, flags, ts);
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if (r < 0)
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goto fail;
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if (rename(p, fn) < 0) {
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r = -errno;
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goto fail;
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}
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return 0;
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fail:
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(void) unlink(p);
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return r;
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}
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int write_string_file_ts(
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const char *fn,
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const char *line,
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WriteStringFileFlags flags,
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struct timespec *ts) {
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_cleanup_fclose_ FILE *f = NULL;
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int q, r;
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assert(fn);
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assert(line);
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/* We don't know how to verify whether the file contents was already on-disk. */
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assert(!((flags & WRITE_STRING_FILE_VERIFY_ON_FAILURE) && (flags & WRITE_STRING_FILE_SYNC)));
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if (flags & WRITE_STRING_FILE_ATOMIC) {
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assert(flags & WRITE_STRING_FILE_CREATE);
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r = write_string_file_atomic(fn, line, flags, ts);
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if (r < 0)
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goto fail;
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return r;
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} else
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assert(!ts);
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if (flags & WRITE_STRING_FILE_CREATE) {
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f = fopen(fn, "we");
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if (!f) {
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r = -errno;
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goto fail;
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}
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} else {
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int fd;
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/* We manually build our own version of fopen(..., "we") that
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* works without O_CREAT */
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fd = open(fn, O_WRONLY|O_CLOEXEC|O_NOCTTY | ((flags & WRITE_STRING_FILE_NOFOLLOW) ? O_NOFOLLOW : 0));
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if (fd < 0) {
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r = -errno;
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goto fail;
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}
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f = fdopen(fd, "w");
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if (!f) {
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r = -errno;
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safe_close(fd);
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goto fail;
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}
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}
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(void) __fsetlocking(f, FSETLOCKING_BYCALLER);
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if (flags & WRITE_STRING_FILE_DISABLE_BUFFER)
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setvbuf(f, NULL, _IONBF, 0);
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r = write_string_stream_ts(f, line, flags, ts);
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if (r < 0)
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goto fail;
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return 0;
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fail:
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if (!(flags & WRITE_STRING_FILE_VERIFY_ON_FAILURE))
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return r;
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f = safe_fclose(f);
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/* OK, the operation failed, but let's see if the right
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* contents in place already. If so, eat up the error. */
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q = verify_file(fn, line, !(flags & WRITE_STRING_FILE_AVOID_NEWLINE));
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if (q <= 0)
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return r;
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return 0;
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}
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int write_string_filef(
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const char *fn,
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WriteStringFileFlags flags,
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const char *format, ...) {
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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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va_start(ap, format);
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r = vasprintf(&p, format, ap);
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va_end(ap);
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if (r < 0)
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return -ENOMEM;
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return write_string_file(fn, p, flags);
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}
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int read_one_line_file(const char *fn, char **line) {
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_cleanup_fclose_ FILE *f = NULL;
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int r;
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assert(fn);
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assert(line);
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f = fopen(fn, "re");
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if (!f)
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return -errno;
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(void) __fsetlocking(f, FSETLOCKING_BYCALLER);
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r = read_line(f, LONG_LINE_MAX, line);
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return r < 0 ? r : 0;
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}
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int verify_file(const char *fn, const char *blob, bool accept_extra_nl) {
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_cleanup_fclose_ FILE *f = NULL;
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_cleanup_free_ char *buf = NULL;
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size_t l, k;
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assert(fn);
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assert(blob);
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l = strlen(blob);
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if (accept_extra_nl && endswith(blob, "\n"))
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accept_extra_nl = false;
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buf = malloc(l + accept_extra_nl + 1);
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if (!buf)
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return -ENOMEM;
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f = fopen(fn, "re");
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if (!f)
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return -errno;
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(void) __fsetlocking(f, FSETLOCKING_BYCALLER);
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/* We try to read one byte more than we need, so that we know whether we hit eof */
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errno = 0;
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k = fread(buf, 1, l + accept_extra_nl + 1, f);
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if (ferror(f))
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return errno > 0 ? -errno : -EIO;
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if (k != l && k != l + accept_extra_nl)
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return 0;
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if (memcmp(buf, blob, l) != 0)
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return 0;
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if (k > l && buf[l] != '\n')
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return 0;
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return 1;
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}
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int read_full_stream(FILE *f, char **contents, size_t *size) {
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_cleanup_free_ char *buf = NULL;
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struct stat st;
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size_t n, l;
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int fd;
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assert(f);
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assert(contents);
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n = LINE_MAX;
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fd = fileno(f);
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if (fd >= 0) { /* If the FILE* object is backed by an fd (as opposed to memory or such, see fmemopen(), let's
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* optimize our buffering) */
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if (fstat(fileno(f), &st) < 0)
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return -errno;
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if (S_ISREG(st.st_mode)) {
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/* Safety check */
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if (st.st_size > READ_FULL_BYTES_MAX)
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return -E2BIG;
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/* Start with the right file size, but be prepared for files from /proc which generally report a file
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* size of 0. Note that we increase the size to read here by one, so that the first read attempt
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* already makes us notice the EOF. */
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if (st.st_size > 0)
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n = st.st_size + 1;
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}
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}
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l = 0;
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for (;;) {
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char *t;
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size_t k;
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t = realloc(buf, n + 1);
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if (!t)
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return -ENOMEM;
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buf = t;
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errno = 0;
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k = fread(buf + l, 1, n - l, f);
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if (k > 0)
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l += k;
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if (ferror(f))
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return errno > 0 ? -errno : -EIO;
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if (feof(f))
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break;
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/* We aren't expecting fread() to return a short read outside
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* of (error && eof), assert buffer is full and enlarge buffer.
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*/
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assert(l == n);
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/* Safety check */
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if (n >= READ_FULL_BYTES_MAX)
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return -E2BIG;
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n = MIN(n * 2, READ_FULL_BYTES_MAX);
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}
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buf[l] = 0;
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*contents = TAKE_PTR(buf);
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if (size)
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*size = l;
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return 0;
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}
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int read_full_file(const char *fn, char **contents, size_t *size) {
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_cleanup_fclose_ FILE *f = NULL;
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assert(fn);
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assert(contents);
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f = fopen(fn, "re");
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if (!f)
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return -errno;
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(void) __fsetlocking(f, FSETLOCKING_BYCALLER);
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return read_full_stream(f, contents, size);
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}
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int executable_is_script(const char *path, char **interpreter) {
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_cleanup_free_ char *line = NULL;
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size_t len;
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char *ans;
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int r;
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assert(path);
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r = read_one_line_file(path, &line);
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if (r == -ENOBUFS) /* First line overly long? if so, then it's not a script */
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return 0;
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if (r < 0)
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return r;
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if (!startswith(line, "#!"))
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return 0;
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ans = strstrip(line + 2);
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len = strcspn(ans, " \t");
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if (len == 0)
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return 0;
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ans = strndup(ans, len);
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if (!ans)
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return -ENOMEM;
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*interpreter = ans;
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return 1;
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}
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/**
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* Retrieve one field from a file like /proc/self/status. pattern
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* should not include whitespace or the delimiter (':'). pattern matches only
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* the beginning of a line. Whitespace before ':' is skipped. Whitespace and
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* zeros after the ':' will be skipped. field must be freed afterwards.
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* terminator specifies the terminating characters of the field value (not
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* included in the value).
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*/
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int get_proc_field(const char *filename, const char *pattern, const char *terminator, char **field) {
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_cleanup_free_ char *status = NULL;
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char *t, *f;
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size_t len;
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int r;
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assert(terminator);
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assert(filename);
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assert(pattern);
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assert(field);
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r = read_full_file(filename, &status, NULL);
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if (r < 0)
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return r;
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t = status;
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do {
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bool pattern_ok;
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do {
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t = strstr(t, pattern);
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if (!t)
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return -ENOENT;
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/* Check that pattern occurs in beginning of line. */
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pattern_ok = (t == status || t[-1] == '\n');
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t += strlen(pattern);
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} while (!pattern_ok);
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t += strspn(t, " \t");
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if (!*t)
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return -ENOENT;
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} while (*t != ':');
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t++;
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if (*t) {
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t += strspn(t, " \t");
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/* Also skip zeros, because when this is used for
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* capabilities, we don't want the zeros. This way the
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* same capability set always maps to the same string,
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* irrespective of the total capability set size. For
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* other numbers it shouldn't matter. */
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t += strspn(t, "0");
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/* Back off one char if there's nothing but whitespace
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and zeros */
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if (!*t || isspace(*t))
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t--;
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}
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len = strcspn(t, terminator);
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f = strndup(t, len);
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if (!f)
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return -ENOMEM;
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*field = f;
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return 0;
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}
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DIR *xopendirat(int fd, const char *name, int flags) {
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int nfd;
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DIR *d;
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assert(!(flags & O_CREAT));
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nfd = openat(fd, name, O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC|flags, 0);
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if (nfd < 0)
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return NULL;
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d = fdopendir(nfd);
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if (!d) {
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safe_close(nfd);
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return NULL;
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}
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return d;
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}
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static int search_and_fopen_internal(const char *path, const char *mode, const char *root, char **search, FILE **_f) {
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char **i;
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assert(path);
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assert(mode);
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assert(_f);
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if (!path_strv_resolve_uniq(search, root))
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return -ENOMEM;
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STRV_FOREACH(i, search) {
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_cleanup_free_ char *p = NULL;
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FILE *f;
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if (root)
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p = strjoin(root, *i, "/", path);
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else
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p = strjoin(*i, "/", path);
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if (!p)
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return -ENOMEM;
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f = fopen(p, mode);
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if (f) {
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*_f = f;
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return 0;
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}
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if (errno != ENOENT)
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return -errno;
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}
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return -ENOENT;
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}
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int search_and_fopen(const char *path, const char *mode, const char *root, const char **search, FILE **_f) {
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_cleanup_strv_free_ char **copy = NULL;
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assert(path);
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assert(mode);
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assert(_f);
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if (path_is_absolute(path)) {
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FILE *f;
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f = fopen(path, mode);
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if (f) {
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*_f = f;
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return 0;
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}
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return -errno;
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}
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copy = strv_copy((char**) search);
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if (!copy)
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return -ENOMEM;
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return search_and_fopen_internal(path, mode, root, copy, _f);
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}
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int search_and_fopen_nulstr(const char *path, const char *mode, const char *root, const char *search, FILE **_f) {
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_cleanup_strv_free_ char **s = NULL;
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if (path_is_absolute(path)) {
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FILE *f;
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f = fopen(path, mode);
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if (f) {
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*_f = f;
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return 0;
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}
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return -errno;
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}
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s = strv_split_nulstr(search);
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if (!s)
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return -ENOMEM;
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return search_and_fopen_internal(path, mode, root, s, _f);
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}
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int fflush_and_check(FILE *f) {
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assert(f);
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errno = 0;
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fflush(f);
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if (ferror(f))
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return errno > 0 ? -errno : -EIO;
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return 0;
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}
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int fflush_sync_and_check(FILE *f) {
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int r;
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assert(f);
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r = fflush_and_check(f);
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if (r < 0)
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return r;
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if (fsync(fileno(f)) < 0)
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return -errno;
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r = fsync_directory_of_file(fileno(f));
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if (r < 0)
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return r;
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return 0;
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}
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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);
|
|
}
|
|
|
|
int read_nul_string(FILE *f, char **ret) {
|
|
_cleanup_free_ char *x = NULL;
|
|
size_t allocated = 0, n = 0;
|
|
|
|
assert(f);
|
|
assert(ret);
|
|
|
|
/* Reads a NUL-terminated string from the specified file. */
|
|
|
|
for (;;) {
|
|
int c;
|
|
|
|
if (!GREEDY_REALLOC(x, allocated, n+2))
|
|
return -ENOMEM;
|
|
|
|
c = fgetc(f);
|
|
if (c == 0) /* Terminate at NUL byte */
|
|
break;
|
|
if (c == EOF) {
|
|
if (ferror(f))
|
|
return -errno;
|
|
break; /* Terminate at EOF */
|
|
}
|
|
|
|
x[n++] = (char) c;
|
|
}
|
|
|
|
if (x)
|
|
x[n] = 0;
|
|
else {
|
|
x = new0(char, 1);
|
|
if (!x)
|
|
return -ENOMEM;
|
|
}
|
|
|
|
*ret = TAKE_PTR(x);
|
|
|
|
return 0;
|
|
}
|
|
|
|
DEFINE_TRIVIAL_CLEANUP_FUNC(FILE*, funlockfile);
|
|
|
|
int read_line(FILE *f, size_t limit, char **ret) {
|
|
_cleanup_free_ char *buffer = NULL;
|
|
size_t n = 0, allocated = 0, count = 0;
|
|
|
|
assert(f);
|
|
|
|
/* Something like a bounded version of getline().
|
|
*
|
|
* Considers EOF, \n and \0 end of line delimiters, and does not include these delimiters in the string
|
|
* returned.
|
|
*
|
|
* 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;
|
|
flockfile(f);
|
|
|
|
for (;;) {
|
|
int c;
|
|
|
|
if (n >= limit)
|
|
return -ENOBUFS;
|
|
|
|
errno = 0;
|
|
c = fgetc_unlocked(f);
|
|
if (c == EOF) {
|
|
/* if we read an error, and have no data to return, then propagate the error */
|
|
if (ferror_unlocked(f) && n == 0)
|
|
return errno > 0 ? -errno : -EIO;
|
|
|
|
break;
|
|
}
|
|
|
|
count++;
|
|
|
|
if (IN_SET(c, '\n', 0)) /* Reached a delimiter */
|
|
break;
|
|
|
|
if (ret) {
|
|
if (!GREEDY_REALLOC(buffer, allocated, n + 2))
|
|
return -ENOMEM;
|
|
|
|
buffer[n] = (char) c;
|
|
}
|
|
|
|
n++;
|
|
}
|
|
}
|
|
|
|
if (ret) {
|
|
buffer[n] = 0;
|
|
|
|
*ret = TAKE_PTR(buffer);
|
|
}
|
|
|
|
return (int) count;
|
|
}
|