diff options
| -rw-r--r-- | src/basic/fileio.c | 109 | ||||
| -rw-r--r-- | src/basic/fileio.h | 12 |
2 files changed, 115 insertions, 6 deletions
diff --git a/src/basic/fileio.c b/src/basic/fileio.c index 7edc31d0a..7355db031 100644 --- a/src/basic/fileio.c +++ b/src/basic/fileio.c @@ -70,7 +70,7 @@ int write_string_stream_ts(FILE *f, const char *line, bool enforce_newline, stru return fflush_and_check(f); } -static int write_string_file_atomic(const char *fn, const char *line, bool enforce_newline) { +static int write_string_file_atomic(const char *fn, const char *line, bool enforce_newline, bool do_fsync) { _cleanup_fclose_ FILE *f = NULL; _cleanup_free_ char *p = NULL; int r; @@ -85,6 +85,9 @@ static int write_string_file_atomic(const char *fn, const char *line, bool enfor (void) fchmod_umask(fileno(f), 0644); r = write_string_stream(f, line, enforce_newline); + if (r >= 0 && do_fsync) + r = fflush_sync_and_check(f); + if (r >= 0) { if (rename(p, fn) < 0) r = -errno; @@ -103,10 +106,14 @@ int write_string_file_ts(const char *fn, const char *line, WriteStringFileFlags 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 & WRITE_STRING_FILE_AVOID_NEWLINE)); + r = write_string_file_atomic(fn, line, !(flags & WRITE_STRING_FILE_AVOID_NEWLINE), + flags & WRITE_STRING_FILE_SYNC); if (r < 0) goto fail; @@ -143,6 +150,12 @@ int write_string_file_ts(const char *fn, const char *line, WriteStringFileFlags if (r < 0) goto fail; + if (flags & WRITE_STRING_FILE_SYNC) { + r = fflush_sync_and_check(f); + if (r < 0) + return r; + } + return 0; fail: @@ -1131,6 +1144,21 @@ int fflush_and_check(FILE *f) { 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; + + return 0; +} + /* This is much like mkostemp() but is subject to umask(). */ int mkostemp_safe(char *pattern) { _cleanup_umask_ mode_t u = 0; @@ -1509,3 +1537,80 @@ int mkdtemp_malloc(const char *template, char **ret) { return 0; } #endif // 0 + +int read_line(FILE *f, size_t limit, char **ret) { + _cleanup_free_ char *buffer = NULL; + size_t n = 0, allocated = 0, count = 0; + int r; + + 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; + } + + flockfile(f); + + for (;;) { + int c; + + if (n >= limit) { + funlockfile(f); + 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) { + r = errno > 0 ? -errno : -EIO; + funlockfile(f); + return r; + } + + break; + } + + count++; + + if (IN_SET(c, '\n', 0)) /* Reached a delimiter */ + break; + + if (ret) { + if (!GREEDY_REALLOC(buffer, allocated, n + 2)) { + funlockfile(f); + return -ENOMEM; + } + + buffer[n] = (char) c; + } + + n++; + } + + funlockfile(f); + + if (ret) { + buffer[n] = 0; + + *ret = buffer; + buffer = NULL; + } + + return (int) count; +} diff --git a/src/basic/fileio.h b/src/basic/fileio.h index fa223fdf5..2ff3b434d 100644 --- a/src/basic/fileio.h +++ b/src/basic/fileio.h @@ -29,10 +29,11 @@ #include "time-util.h" typedef enum { - WRITE_STRING_FILE_CREATE = 1, - WRITE_STRING_FILE_ATOMIC = 2, - WRITE_STRING_FILE_AVOID_NEWLINE = 4, - WRITE_STRING_FILE_VERIFY_ON_FAILURE = 8, + WRITE_STRING_FILE_CREATE = 1<<0, + WRITE_STRING_FILE_ATOMIC = 1<<1, + WRITE_STRING_FILE_AVOID_NEWLINE = 1<<2, + WRITE_STRING_FILE_VERIFY_ON_FAILURE = 1<<3, + WRITE_STRING_FILE_SYNC = 1<<4, } WriteStringFileFlags; int write_string_stream_ts(FILE *f, const char *line, bool enforce_newline, struct timespec *ts); @@ -83,6 +84,7 @@ int search_and_fopen_nulstr(const char *path, const char *mode, const char *root } else int fflush_and_check(FILE *f); +int fflush_sync_and_check(FILE *f); int fopen_temporary(const char *path, FILE **_f, char **_temp_path); int mkostemp_safe(char *pattern); @@ -111,3 +113,5 @@ int read_nul_string(FILE *f, char **ret); int mkdtemp_malloc(const char *template, char **ret); #endif // 0 + +int read_line(FILE *f, size_t limit, char **ret); |