gdbsupport: convert FILEIO_* macros to an enum

Converting from free-form macros to an enum gives a bit of type-safety.
This caught places where we would assign host error numbers to what
should contain a target fileio error number, for instance in
target_fileio_pread.

I added the FILEIO_SUCCESS enumerator, because
remote.c:remote_hostio_parse_result initializes the remote_errno output
variable to 0.  It seems better to have an explicit enumerator than to
assign a value for which there is no enumerator.  I considered
initializing this variable to FILEIO_EUNKNOWN instead, such that if the
remote side replies with an error and omits the errno value, we'll get
an errno that represents an error instead of 0 (which reprensents no
error).  But it's not clear what the consequences of that change would
be, so I prefer to err on the side of caution and just keep the existing
behavior (there is no intended change in behavior with this patch).

Note that remote_hostio_parse_resul still reads blindly what the remote
side sends as a target errno into this variable, so we can still end up
with a nonsensical value here.  It's not good, but out of the scope of
this patch.

Convert host_to_fileio_error and fileio_errno_to_host to return / accept
a fileio_error instead of an int, and cascade the change in the whole
chain that uses that.

Change-Id: I454b0e3fcf0732447bc872252fa8e57d138b0e03

1 files changed, 23 insertions, 23 deletions

diff --git a/gdb/target.c b/gdb/target.c
index 9d698af..2856098 100644
--- a/gdb/target.c
+++ b/gdb/target.c
@@ -3206,7 +3206,7 @@ fileio_fd_to_fh (int fd)
 int
 target_ops::fileio_open (struct inferior *inf, const char *filename,
 			 int flags, int mode, int warn_if_slow,
-			 int *target_errno)
+			 fileio_error *target_errno)
 {
   *target_errno = FILEIO_ENOSYS;
   return -1;
@@ -3214,7 +3214,7 @@ target_ops::fileio_open (struct inferior *inf, const char *filename,
 
 int
 target_ops::fileio_pwrite (int fd, const gdb_byte *write_buf, int len,
-			   ULONGEST offset, int *target_errno)
+			   ULONGEST offset, fileio_error *target_errno)
 {
   *target_errno = FILEIO_ENOSYS;
   return -1;
@@ -3222,21 +3222,21 @@ target_ops::fileio_pwrite (int fd, const gdb_byte *write_buf, int len,
 
 int
 target_ops::fileio_pread (int fd, gdb_byte *read_buf, int len,
-			  ULONGEST offset, int *target_errno)
+			  ULONGEST offset, fileio_error *target_errno)
 {
   *target_errno = FILEIO_ENOSYS;
   return -1;
 }
 
 int
-target_ops::fileio_fstat (int fd, struct stat *sb, int *target_errno)
+target_ops::fileio_fstat (int fd, struct stat *sb, fileio_error *target_errno)
 {
   *target_errno = FILEIO_ENOSYS;
   return -1;
 }
 
 int
-target_ops::fileio_close (int fd, int *target_errno)
+target_ops::fileio_close (int fd, fileio_error *target_errno)
 {
   *target_errno = FILEIO_ENOSYS;
   return -1;
@@ -3244,7 +3244,7 @@ target_ops::fileio_close (int fd, int *target_errno)
 
 int
 target_ops::fileio_unlink (struct inferior *inf, const char *filename,
-			   int *target_errno)
+			   fileio_error *target_errno)
 {
   *target_errno = FILEIO_ENOSYS;
   return -1;
@@ -3252,7 +3252,7 @@ target_ops::fileio_unlink (struct inferior *inf, const char *filename,
 
 gdb::optional<std::string>
 target_ops::fileio_readlink (struct inferior *inf, const char *filename,
-			     int *target_errno)
+			     fileio_error *target_errno)
 {
   *target_errno = FILEIO_ENOSYS;
   return {};
@@ -3262,7 +3262,7 @@ target_ops::fileio_readlink (struct inferior *inf, const char *filename,
 
 int
 target_fileio_open (struct inferior *inf, const char *filename,
-		    int flags, int mode, bool warn_if_slow, int *target_errno)
+		    int flags, int mode, bool warn_if_slow, fileio_error *target_errno)
 {
   for (target_ops *t = default_fileio_target (); t != NULL; t = t->beneath ())
     {
@@ -3296,15 +3296,15 @@ target_fileio_open (struct inferior *inf, const char *filename,
 
 int
 target_fileio_pwrite (int fd, const gdb_byte *write_buf, int len,
-		      ULONGEST offset, int *target_errno)
+		      ULONGEST offset, fileio_error *target_errno)
 {
   fileio_fh_t *fh = fileio_fd_to_fh (fd);
   int ret = -1;
 
   if (fh->is_closed ())
-    *target_errno = EBADF;
+    *target_errno = FILEIO_EBADF;
   else if (fh->target == NULL)
-    *target_errno = EIO;
+    *target_errno = FILEIO_EIO;
   else
     ret = fh->target->fileio_pwrite (fh->target_fd, write_buf,
 				     len, offset, target_errno);
@@ -3322,15 +3322,15 @@ target_fileio_pwrite (int fd, const gdb_byte *write_buf, int len,
 
 int
 target_fileio_pread (int fd, gdb_byte *read_buf, int len,
-		     ULONGEST offset, int *target_errno)
+		     ULONGEST offset, fileio_error *target_errno)
 {
   fileio_fh_t *fh = fileio_fd_to_fh (fd);
   int ret = -1;
 
   if (fh->is_closed ())
-    *target_errno = EBADF;
+    *target_errno = FILEIO_EBADF;
   else if (fh->target == NULL)
-    *target_errno = EIO;
+    *target_errno = FILEIO_EIO;
   else
     ret = fh->target->fileio_pread (fh->target_fd, read_buf,
 				    len, offset, target_errno);
@@ -3347,15 +3347,15 @@ target_fileio_pread (int fd, gdb_byte *read_buf, int len,
 /* See target.h.  */
 
 int
-target_fileio_fstat (int fd, struct stat *sb, int *target_errno)
+target_fileio_fstat (int fd, struct stat *sb, fileio_error *target_errno)
 {
   fileio_fh_t *fh = fileio_fd_to_fh (fd);
   int ret = -1;
 
   if (fh->is_closed ())
-    *target_errno = EBADF;
+    *target_errno = FILEIO_EBADF;
   else if (fh->target == NULL)
-    *target_errno = EIO;
+    *target_errno = FILEIO_EIO;
   else
     ret = fh->target->fileio_fstat (fh->target_fd, sb, target_errno);
 
@@ -3369,13 +3369,13 @@ target_fileio_fstat (int fd, struct stat *sb, int *target_errno)
 /* See target.h.  */
 
 int
-target_fileio_close (int fd, int *target_errno)
+target_fileio_close (int fd, fileio_error *target_errno)
 {
   fileio_fh_t *fh = fileio_fd_to_fh (fd);
   int ret = -1;
 
   if (fh->is_closed ())
-    *target_errno = EBADF;
+    *target_errno = FILEIO_EBADF;
   else
     {
       if (fh->target != NULL)
@@ -3397,7 +3397,7 @@ target_fileio_close (int fd, int *target_errno)
 
 int
 target_fileio_unlink (struct inferior *inf, const char *filename,
-		      int *target_errno)
+		      fileio_error *target_errno)
 {
   for (target_ops *t = default_fileio_target (); t != NULL; t = t->beneath ())
     {
@@ -3423,7 +3423,7 @@ target_fileio_unlink (struct inferior *inf, const char *filename,
 
 gdb::optional<std::string>
 target_fileio_readlink (struct inferior *inf, const char *filename,
-			int *target_errno)
+			fileio_error *target_errno)
 {
   for (target_ops *t = default_fileio_target (); t != NULL; t = t->beneath ())
     {
@@ -3461,7 +3461,7 @@ public:
   {
     if (m_fd >= 0)
       {
-	int target_errno;
+	fileio_error target_errno;
 
 	target_fileio_close (m_fd, &target_errno);
       }
@@ -3493,7 +3493,7 @@ target_fileio_read_alloc_1 (struct inferior *inf, const char *filename,
   size_t buf_alloc, buf_pos;
   gdb_byte *buf;
   LONGEST n;
-  int target_errno;
+  fileio_error target_errno;
 
   scoped_target_fd fd (target_fileio_open (inf, filename, FILEIO_O_RDONLY,
 					   0700, false, &target_errno));