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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-04 12:17:33 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-04 12:17:33 +0000 |
commit | 5e45211a64149b3c659b90ff2de6fa982a5a93ed (patch) | |
tree | 739caf8c461053357daa9f162bef34516c7bf452 /src/port/pread.c | |
parent | Initial commit. (diff) | |
download | postgresql-15-5e45211a64149b3c659b90ff2de6fa982a5a93ed.tar.xz postgresql-15-5e45211a64149b3c659b90ff2de6fa982a5a93ed.zip |
Adding upstream version 15.5.upstream/15.5
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/port/pread.c')
-rw-r--r-- | src/port/pread.c | 58 |
1 files changed, 58 insertions, 0 deletions
diff --git a/src/port/pread.c b/src/port/pread.c new file mode 100644 index 0000000..bbf12ee --- /dev/null +++ b/src/port/pread.c @@ -0,0 +1,58 @@ +/*------------------------------------------------------------------------- + * + * pread.c + * Implementation of pread(2) for platforms that lack one. + * + * Portions Copyright (c) 1996-2022, PostgreSQL Global Development Group + * + * IDENTIFICATION + * src/port/pread.c + * + * Note that this implementation changes the current file position, unlike + * the POSIX function, so we use the name pg_pread(). + * + *------------------------------------------------------------------------- + */ + + +#include "c.h" + +#ifdef WIN32 +#include <windows.h> +#else +#include <unistd.h> +#endif + +ssize_t +pg_pread(int fd, void *buf, size_t size, off_t offset) +{ +#ifdef WIN32 + OVERLAPPED overlapped = {0}; + HANDLE handle; + DWORD result; + + handle = (HANDLE) _get_osfhandle(fd); + if (handle == INVALID_HANDLE_VALUE) + { + errno = EBADF; + return -1; + } + + overlapped.Offset = offset; + if (!ReadFile(handle, buf, size, &result, &overlapped)) + { + if (GetLastError() == ERROR_HANDLE_EOF) + return 0; + + _dosmaperr(GetLastError()); + return -1; + } + + return result; +#else + if (lseek(fd, offset, SEEK_SET) < 0) + return -1; + + return read(fd, buf, size); +#endif +} |