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-rw-r--r--src/stdio/fopencookie.c138
1 files changed, 138 insertions, 0 deletions
diff --git a/src/stdio/fopencookie.c b/src/stdio/fopencookie.c
new file mode 100644
index 00000000..2f46dd53
--- /dev/null
+++ b/src/stdio/fopencookie.c
@@ -0,0 +1,138 @@
+#define _GNU_SOURCE
+#include "stdio_impl.h"
+#include <stdlib.h>
+#include <sys/ioctl.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <string.h>
+
+struct fcookie {
+ void *cookie;
+ cookie_io_functions_t iofuncs;
+};
+
+struct cookie_FILE {
+ FILE f;
+ struct fcookie fc;
+ unsigned char buf[UNGET+BUFSIZ];
+};
+
+static size_t cookieread(FILE *f, unsigned char *buf, size_t len)
+{
+ struct fcookie *fc = f->cookie;
+ ssize_t ret = -1;
+ size_t remain = len, readlen = 0;
+ size_t len2 = len - !!f->buf_size;
+
+ if (!fc->iofuncs.read) goto bail;
+
+ if (len2) {
+ ret = fc->iofuncs.read(fc->cookie, (char *) buf, len2);
+ if (ret <= 0) goto bail;
+
+ readlen += ret;
+ remain -= ret;
+ }
+
+ if (!f->buf_size || remain > !!f->buf_size) return readlen;
+
+ f->rpos = f->buf;
+ ret = fc->iofuncs.read(fc->cookie, (char *) f->rpos, f->buf_size);
+ if (ret <= 0) goto bail;
+ f->rend = f->rpos + ret;
+
+ buf[readlen++] = *f->rpos++;
+
+ return readlen;
+
+bail:
+ f->flags |= ret == 0 ? F_EOF : F_ERR;
+ f->rpos = f->rend = f->buf;
+ return readlen;
+}
+
+static size_t cookiewrite(FILE *f, const unsigned char *buf, size_t len)
+{
+ struct fcookie *fc = f->cookie;
+ ssize_t ret;
+ size_t len2 = f->wpos - f->wbase;
+ if (!fc->iofuncs.write) return len;
+ if (len2) {
+ f->wpos = f->wbase;
+ if (cookiewrite(f, f->wpos, len2) < len2) return 0;
+ }
+ ret = fc->iofuncs.write(fc->cookie, (const char *) buf, len);
+ if (ret < 0) {
+ f->wpos = f->wbase = f->wend = 0;
+ f->flags |= F_ERR;
+ return 0;
+ }
+ return ret;
+}
+
+static off_t cookieseek(FILE *f, off_t off, int whence)
+{
+ struct fcookie *fc = f->cookie;
+ int res;
+ if (whence > 2U) {
+ errno = EINVAL;
+ return -1;
+ }
+ if (!fc->iofuncs.seek) {
+ errno = ENOTSUP;
+ return -1;
+ }
+ res = fc->iofuncs.seek(fc->cookie, &off, whence);
+ if (res < 0)
+ return res;
+ return off;
+}
+
+static int cookieclose(FILE *f)
+{
+ struct fcookie *fc = f->cookie;
+ if (fc->iofuncs.close) return fc->iofuncs.close(fc->cookie);
+ return 0;
+}
+
+FILE *fopencookie(void *cookie, const char *mode, cookie_io_functions_t iofuncs)
+{
+ struct cookie_FILE *f;
+
+ /* Check for valid initial mode character */
+ if (!strchr("rwa", *mode)) {
+ errno = EINVAL;
+ return 0;
+ }
+
+ /* Allocate FILE+fcookie+buffer or fail */
+ if (!(f=malloc(sizeof *f))) return 0;
+
+ /* Zero-fill only the struct, not the buffer */
+ memset(&f->f, 0, sizeof f->f);
+
+ /* Impose mode restrictions */
+ if (!strchr(mode, '+')) f->f.flags = (*mode == 'r') ? F_NOWR : F_NORD;
+
+ /* Set up our fcookie */
+ f->fc.cookie = cookie;
+ f->fc.iofuncs.read = iofuncs.read;
+ f->fc.iofuncs.write = iofuncs.write;
+ f->fc.iofuncs.seek = iofuncs.seek;
+ f->fc.iofuncs.close = iofuncs.close;
+
+ f->f.fd = -1;
+ f->f.cookie = &f->fc;
+ f->f.buf = f->buf + UNGET;
+ f->f.buf_size = BUFSIZ;
+ f->f.lbf = EOF;
+
+ /* Initialize op ptrs. No problem if some are unneeded. */
+ f->f.read = cookieread;
+ f->f.write = cookiewrite;
+ f->f.seek = cookieseek;
+ f->f.close = cookieclose;
+
+ /* Add new FILE to open file list */
+ return __ofl_add(&f->f);
+}