Commit 3e9e69098af2014a0c3fe9e46cddcb5365dd538b
2008-11-03T17:14:25
Redefine git_fread, git_fwrite to transfer the whole unit We never want to accept a short read or a short write when transferring data to or from a local file. Either the entire read (or write) completes or the operation failed and we will not recover gracefully from it. Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
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diff --git a/include/git/os/unix.h b/include/git/os/unix.h
index dd58389..56f77b9 100644
--- a/include/git/os/unix.h
+++ b/include/git/os/unix.h
@@ -54,58 +54,55 @@ typedef int git_file;
* - O_WRONLY: Open the file for writing.
* - O_RDWR: Open the file for both reading and writing.
*
+ * @param out descriptor storage to populate on success.
* @param path path name of the file to open.
* @param flags bitmask of access requested to the file.
- * @return the opened file descriptor; <0 if the open failed.
- */
-static inline git_file git_fopen(const char *path, int flags)
-{
- return open(path, flags);
-}
-
-/**
- * Close an open file descriptor.
- * @param fd descriptor to close.
- * @return 0 on success; <0 if the descriptor close failed.
+ * @return
+ * - On success, GIT_SUCCESS.
+ * - On error, <0.
*/
-static inline int git_fclose(git_file fd)
-{
- return close(fd);
-}
+GIT_EXTERN(int) git_fopen(git_file *out, const char *path, int flags);
/**
* Read from an open file descriptor at the current position.
*
- * Less than the number of requested bytes may be read. The
- * read is automatically restarted if it fails due to a signal
- * being delivered to the calling thread.
+ * Exactly the requested number of bytes is read. If the stream
+ * ends early, an error is indicated, and the exact number of bytes
+ * transferred is unspecified.
*
* @param fd open descriptor.
* @param buf buffer to store the read data into.
* @param cnt number of bytes to transfer.
* @return
- * - On success, actual number of bytes read.
- * - On EOF, 0.
- * - On failure, <0.
+ * - On success, GIT_SUCCESS.
+ * - On error, <0.
*/
-GIT_EXTERN(ssize_t) git_fread(git_file fd, void *buf, size_t cnt);
+GIT_EXTERN(int) git_fread(git_file fd, void *buf, size_t cnt);
/**
* Write to an open file descriptor at the current position.
*
- * Less than the number of requested bytes may be written. The
- * write is automatically restarted if it fails due to a signal
- * being delivered to the calling thread.
+ * Exactly the requested number of bytes is written. If the stream
+ * ends early, an error is indicated, and the exact number of bytes
+ * transferred is unspecified.
*
* @param fd open descriptor.
* @param buf buffer to write data from.
* @param cnt number of bytes to transfer.
* @return
- * - On success, actual number of bytes written.
- * - On EOF, 0.
- * - On failure, <0.
+ * - On success, GIT_SUCCESS.
+ * - On error, <0.
+ */
+GIT_EXTERN(int) git_fwrite(git_file fd, void *buf, size_t cnt);
+
+/**
+ * Close an open file descriptor.
+ * @param fd descriptor to close.
+ * @return
+ * - On success, GIT_SUCCESS.
+ * - On error, <0.
*/
-GIT_EXTERN(ssize_t) git_fwrite(git_file fd, void *buf, size_t cnt);
+#define git_fclose(fd) close(fd)
/** @} */
GIT_END_DECL
diff --git a/src/os/unix.c b/src/os/unix.c
index d132e97..767f20c 100644
--- a/src/os/unix.c
+++ b/src/os/unix.c
@@ -26,22 +26,51 @@
#include <errno.h>
#include "git/common.h"
-ssize_t git_fread(git_file fd, void *buf, size_t cnt)
+int git_fopen(git_file *out, const char *path, int flags)
{
- for (;;) {
- ssize_t r = read(fd, buf, cnt);
- if (r < 0 && (errno == EINTR || errno == EAGAIN))
- continue;
- return r;
+ int r = open(path, flags);
+ if (r < 0)
+ return -1;
+ *out = r;
+ return GIT_SUCCESS;
+}
+
+int git_fread(git_file fd, void *buf, size_t cnt)
+{
+ char *b = buf;
+ while (cnt) {
+ ssize_t r = read(fd, b, cnt);
+ if (r < 0) {
+ if (errno == EINTR || errno == EAGAIN)
+ continue;
+ return -1;
+ }
+ if (!r) {
+ errno = EPIPE;
+ return -1;
+ }
+ cnt -= r;
+ b += r;
}
+ return GIT_SUCCESS;
}
-ssize_t git_fwrite(git_file fd, void *buf, size_t cnt)
+int git_fwrite(git_file fd, void *buf, size_t cnt)
{
- for (;;) {
- ssize_t r = write(fd, buf, cnt);
- if (r < 0 && (errno == EINTR || errno == EAGAIN))
- continue;
- return r;
+ char *b = buf;
+ while (cnt) {
+ ssize_t r = write(fd, b, cnt);
+ if (r < 0) {
+ if (errno == EINTR || errno == EAGAIN)
+ continue;
+ return -1;
+ }
+ if (!r) {
+ errno = EPIPE;
+ return -1;
+ }
+ cnt -= r;
+ b += r;
}
+ return GIT_SUCCESS;
}