blob: a9c0fd20e14fa989a0f42701a760b9afa6442d8e [file] [log] [blame] [raw]
/* SPDX-License-Identifier: LGPL-2.1+ */
#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 <string.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#include "alloc-util.h"
#include "fd-util.h"
#include "fileio.h"
#include "fs-util.h"
#include "hexdecoct.h"
#include "log.h"
#include "macro.h"
#include "missing.h"
#include "mkdir.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 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;
}
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,
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) 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_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);
if (flags & WRITE_STRING_FILE_CREATE) {
r = fopen_unlocked(fn, "we", &f);
if (r < 0)
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;
}
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));
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_full_stream_full(
FILE *f,
const char *filename,
ReadFullFileFlags flags,
char **ret_contents,
size_t *ret_size) {
_cleanup_free_ char *buf = NULL;
struct stat st;
size_t n, n_next, l;
int fd, r;
assert(f);
assert(ret_contents);
assert(!FLAGS_SET(flags, READ_FULL_FILE_UNBASE64 | READ_FULL_FILE_UNHEX));
assert(!(flags & (READ_FULL_FILE_UNBASE64 | READ_FULL_FILE_UNHEX)) || ret_size);
n_next = 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(fd, &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_next = st.st_size + 1;
if (flags & READ_FULL_FILE_SECURE)
(void) warn_file_is_world_accessible(filename, &st, NULL, 0);
}
}
n = l = 0;
for (;;) {
char *t;
size_t k;
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);
buf = mfree(buf);
} else {
t = realloc(buf, n_next + 1);
if (!t)
return -ENOMEM;
}
buf = t;
n = n_next;
errno = 0;
k = fread(buf + l, 1, n - l, f);
if (k > 0)
l += k;
if (ferror(f)) {
r = errno_or_else(EIO);
goto finalize;
}
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) {
r = -E2BIG;
goto finalize;
}
n_next = MIN(n * 2, READ_FULL_BYTES_MAX);
}
if (flags & (READ_FULL_FILE_UNBASE64 | READ_FULL_FILE_UNHEX)) {
buf[l++] = 0;
if (flags & READ_FULL_FILE_UNBASE64)
r = unbase64mem_full(buf, l, flags & READ_FULL_FILE_SECURE, (void **) ret_contents, ret_size);
else
r = unhexmem_full(buf, l, flags & READ_FULL_FILE_SECURE, (void **) ret_contents, ret_size);
goto finalize;
}
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(const char *filename, ReadFullFileFlags flags, char **contents, size_t *size) {
_cleanup_fclose_ FILE *f = NULL;
int r;
assert(filename);
assert(contents);
r = fopen_unlocked(filename, "re", &f);
if (r < 0)
return r;
return read_full_stream_full(f, filename, flags, 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;
p = path_join(root, *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_or_else(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, tty = -1;
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) {
/* If we are on a tty, we can't wait for more input. But we expect only
* \n as the single EOL marker, so there is no need to wait. We check
* this condition last to avoid isatty() check if not necessary. */
if (tty < 0)
tty = isatty(fileno(f));
if (tty > 0)
break;
}
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_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;
}