This enables the usage of the stream APIs with arbitrary filedescriptors.
It will be used by a future testcase.
Signed-off-by: Thomas Weißschuh linux@weissschuh.net
---
Willy:
This uses intptr_t instead of uintptr_t as proposed because uintptr_t can not be negative. --- tools/include/nolibc/stdio.h | 60 ++++++++++++++++++++++++-------------------- 1 file changed, 33 insertions(+), 27 deletions(-)
diff --git a/tools/include/nolibc/stdio.h b/tools/include/nolibc/stdio.h index 96ac8afc5aee..edf1009e9203 100644 --- a/tools/include/nolibc/stdio.h +++ b/tools/include/nolibc/stdio.h @@ -21,17 +21,40 @@ #define EOF (-1) #endif
-/* just define FILE as a non-empty type */ +/* just define FILE as a non-empty type. The value of the pointer gives + * the FD: FILE=~fd for fd>=0 or NULL for fd<0. This way positive FILE + * are immediately identified as abnormal entries (i.e. possible copies + * of valid pointers to something else). + */ typedef struct FILE { char dummy[1]; } FILE;
-/* We define the 3 common stdio files as constant invalid pointers that - * are easily recognized. - */ -static __attribute__((unused)) FILE* const stdin = (FILE*)-3; -static __attribute__((unused)) FILE* const stdout = (FILE*)-2; -static __attribute__((unused)) FILE* const stderr = (FILE*)-1; +static __attribute__((unused)) FILE* const stdin = (FILE*)(intptr_t)~STDIN_FILENO; +static __attribute__((unused)) FILE* const stdout = (FILE*)(intptr_t)~STDOUT_FILENO; +static __attribute__((unused)) FILE* const stderr = (FILE*)(intptr_t)~STDERR_FILENO; + +/* provides a FILE* equivalent of fd. The mode is ignored. */ +static __attribute__((unused)) +FILE *fdopen(int fd, const char *mode __attribute__((unused))) +{ + if (fd < 0) + return NULL; + return (FILE*)(intptr_t)~fd; +} + +/* provides the fd from of stream. */ +static __attribute__((unused)) +int fileno(FILE *stream) +{ + intptr_t i = (intptr_t)stream; + + if (i > 0) { + SET_ERRNO(EBADF); + return -1; + } + return ~i; +}
/* getc(), fgetc(), getchar() */
@@ -41,14 +64,8 @@ static __attribute__((unused)) int fgetc(FILE* stream) { unsigned char ch; - int fd;
- if (stream < stdin || stream > stderr) - return EOF; - - fd = 3 + (long)stream; - - if (read(fd, &ch, 1) <= 0) + if (read(fileno(stream), &ch, 1) <= 0) return EOF; return ch; } @@ -68,14 +85,8 @@ static __attribute__((unused)) int fputc(int c, FILE* stream) { unsigned char ch = c; - int fd; - - if (stream < stdin || stream > stderr) - return EOF; - - fd = 3 + (long)stream;
- if (write(fd, &ch, 1) <= 0) + if (write(fileno(stream), &ch, 1) <= 0) return EOF; return ch; } @@ -96,12 +107,7 @@ static __attribute__((unused)) int _fwrite(const void *buf, size_t size, FILE *stream) { ssize_t ret; - int fd; - - if (stream < stdin || stream > stderr) - return EOF; - - fd = 3 + (long)stream; + int fd = fileno(stream);
while (size) { ret = write(fd, buf, size);