diff options
| -rw-r--r-- | qga/commands-posix.c | 120 |
1 files changed, 60 insertions, 60 deletions
diff --git a/qga/commands-posix.c b/qga/commands-posix.c index 12b50b7124..3b2392398e 100644 --- a/qga/commands-posix.c +++ b/qga/commands-posix.c @@ -339,73 +339,73 @@ find_open_flag(const char *mode_str, Error **errp) static FILE * safe_open_or_create(const char *path, const char *mode, Error **errp) { - Error *local_err = NULL; int oflag; + int fd = -1; + FILE *f = NULL; + + oflag = find_open_flag(mode, errp); + if (oflag < 0) { + goto end; + } + + /* If the caller wants / allows creation of a new file, we implement it + * with a two step process: open() + (open() / fchmod()). + * + * First we insist on creating the file exclusively as a new file. If + * that succeeds, we're free to set any file-mode bits on it. (The + * motivation is that we want to set those file-mode bits independently + * of the current umask.) + * + * If the exclusive creation fails because the file already exists + * (EEXIST is not possible for any other reason), we just attempt to + * open the file, but in this case we won't be allowed to change the + * file-mode bits on the preexistent file. + * + * The pathname should never disappear between the two open()s in + * practice. If it happens, then someone very likely tried to race us. + * In this case just go ahead and report the ENOENT from the second + * open() to the caller. + * + * If the caller wants to open a preexistent file, then the first + * open() is decisive and its third argument is ignored, and the second + * open() and the fchmod() are never called. + */ + fd = open(path, oflag | ((oflag & O_CREAT) ? O_EXCL : 0), 0); + if (fd == -1 && errno == EEXIST) { + oflag &= ~(unsigned)O_CREAT; + fd = open(path, oflag); + } + if (fd == -1) { + error_setg_errno(errp, errno, + "failed to open file '%s' (mode: '%s')", + path, mode); + goto end; + } - oflag = find_open_flag(mode, &local_err); - if (local_err == NULL) { - int fd; - - /* If the caller wants / allows creation of a new file, we implement it - * with a two step process: open() + (open() / fchmod()). - * - * First we insist on creating the file exclusively as a new file. If - * that succeeds, we're free to set any file-mode bits on it. (The - * motivation is that we want to set those file-mode bits independently - * of the current umask.) - * - * If the exclusive creation fails because the file already exists - * (EEXIST is not possible for any other reason), we just attempt to - * open the file, but in this case we won't be allowed to change the - * file-mode bits on the preexistent file. - * - * The pathname should never disappear between the two open()s in - * practice. If it happens, then someone very likely tried to race us. - * In this case just go ahead and report the ENOENT from the second - * open() to the caller. - * - * If the caller wants to open a preexistent file, then the first - * open() is decisive and its third argument is ignored, and the second - * open() and the fchmod() are never called. - */ - fd = open(path, oflag | ((oflag & O_CREAT) ? O_EXCL : 0), 0); - if (fd == -1 && errno == EEXIST) { - oflag &= ~(unsigned)O_CREAT; - fd = open(path, oflag); - } + qemu_set_cloexec(fd); - if (fd == -1) { - error_setg_errno(&local_err, errno, "failed to open file '%s' " - "(mode: '%s')", path, mode); - } else { - qemu_set_cloexec(fd); + if ((oflag & O_CREAT) && fchmod(fd, DEFAULT_NEW_FILE_MODE) == -1) { + error_setg_errno(errp, errno, "failed to set permission " + "0%03o on new file '%s' (mode: '%s')", + (unsigned)DEFAULT_NEW_FILE_MODE, path, mode); + goto end; + } - if ((oflag & O_CREAT) && fchmod(fd, DEFAULT_NEW_FILE_MODE) == -1) { - error_setg_errno(&local_err, errno, "failed to set permission " - "0%03o on new file '%s' (mode: '%s')", - (unsigned)DEFAULT_NEW_FILE_MODE, path, mode); - } else { - FILE *f; - - f = fdopen(fd, mode); - if (f == NULL) { - error_setg_errno(&local_err, errno, "failed to associate " - "stdio stream with file descriptor %d, " - "file '%s' (mode: '%s')", fd, path, mode); - } else { - return f; - } - } + f = fdopen(fd, mode); + if (f == NULL) { + error_setg_errno(errp, errno, "failed to associate stdio stream with " + "file descriptor %d, file '%s' (mode: '%s')", + fd, path, mode); + } - close(fd); - if (oflag & O_CREAT) { - unlink(path); - } +end: + if (f == NULL && fd != -1) { + close(fd); + if (oflag & O_CREAT) { + unlink(path); } } - - error_propagate(errp, local_err); - return NULL; + return f; } int64_t qmp_guest_file_open(const char *path, bool has_mode, const char *mode, |