unistd/file: provide safe write/read/open/close functions

JIRA: RTOS-874

stdio/file.c

@@ -32,6 +32,8 @@
 #include <unistd.h>
 #include <limits.h>
 
+#include "../unistd/file-internal.h"
+
 
 #define F_EOF     (1 << 0)
 #define F_WRITING (1 << 1)
@@ -158,42 +160,6 @@ static void file_free(FILE *file)
 }
 
 
-static ssize_t safe_read(int fd, void *buf, size_t size)
-{
-	int err;
-	while ((err = read(fd, buf, size)) < 0 && errno == EINTR) {
-	}
-	return err;
-}
-
-
-static ssize_t safe_write(int fd, const void *buf, size_t size)
-{
-	int err;
-	while ((err = write(fd, buf, size)) < 0 && errno == EINTR) {
-	}
-	return err;
-}
-
-
-static int safe_open(const char *path, int oflag, mode_t mode)
-{
-	int err;
-	while ((err = open(path, oflag, mode)) < 0 && errno == EINTR) {
-	}
-	return err;
-}
-
-
-static int safe_close(int fd)
-{
-	int err;
-	while ((err = close(fd)) < 0 && errno == EINTR) {
-	}
-	return err;
-}
-
-
 int fclose(FILE *file)
 {
 	int err;
@@ -203,7 +169,7 @@ int fclose(FILE *file)
 	}
 
 	fflush(file);
-	while ((err = safe_close(file->fd)) < 0 && errno == EINTR) {
+	while ((err = __safe_close(file->fd)) < 0 && errno == EINTR) {
 	}
 	file_free(file);
 
@@ -222,17 +188,17 @@ FILE *fopen(const char *filename, const char *mode)
 		return NULL;
 	}
 
-	if ((fd = safe_open(filename, m, DEFFILEMODE)) < 0) {
+	if ((fd = __safe_open(filename, m, DEFFILEMODE)) < 0) {
 		return NULL;
 	}
 
 	if ((f = calloc(1, sizeof(FILE))) == NULL) {
-		safe_close(fd);
+		__safe_close(fd);
 		return NULL;
 	}
 
 	if ((f->buffer = buffAlloc(BUFSIZ)) == NULL) {
-		safe_close(fd);
+		__safe_close(fd);
 		free(f);
 		return NULL;
 	}
@@ -307,9 +273,9 @@ FILE *freopen(const char *pathname, const char *mode, FILE *stream)
 	fflush(stream);
 
 	if (pathname != NULL) {
-		safe_close(stream->fd);
+		__safe_close(stream->fd);
 
-		if ((stream->fd = safe_open(pathname, m, DEFFILEMODE)) < 0) {
+		if ((stream->fd = __safe_open(pathname, m, DEFFILEMODE)) < 0) {
 			file_free(stream);
 			return NULL;
 		}
@@ -330,7 +296,7 @@ static int full_read(int fd, void *ptr, size_t size)
 	int total = 0;
 
 	while (size) {
-		if ((err = safe_read(fd, ptr, size)) < 0) {
+		if ((err = __safe_read(fd, ptr, size)) < 0) {
 			return -1;
 		}
 		else if (!err) {
@@ -349,7 +315,7 @@ static int full_write(int fd, const void *ptr, size_t size)
 {
 	int err;
 	while (size) {
-		if ((err = safe_write(fd, ptr, size)) < 0) {
+		if ((err = __safe_write(fd, ptr, size)) < 0) {
 			return -1;
 		}
 		ptr += err;
@@ -397,7 +363,7 @@ size_t fread_unlocked(void *ptr, size_t size, size_t nmemb, FILE *stream)
 
 	/* refill read buffer */
 	if (stream->bufpos == stream->bufeof) {
-		if ((err = safe_read(stream->fd, stream->buffer, stream->bufsz)) == -1) {
+		if ((err = __safe_read(stream->fd, stream->buffer, stream->bufsz)) == -1) {
 			return 0;
 		}
 
@@ -462,7 +428,7 @@ size_t fwrite_unlocked(const void *ptr, size_t size, size_t nmemb, FILE *stream)
 
 	if (stream->buffer == NULL) {
 		/* unbuffered write */
-		if ((err = safe_write(stream->fd, ptr, writesz)) < 0) {
+		if ((err = __safe_write(stream->fd, ptr, writesz)) < 0) {
 			return 0;
 		}
 

stdio/fprintf.c

@@ -20,6 +20,8 @@
 #include "format.h"
 #include "sys/debug.h"
 
+#include "../unistd/file-internal.h"
+
 
 /* clang-format off */
 struct feed_ctx_s {
@@ -37,35 +39,6 @@ struct feed_ctx_s {
 /* clang-format on */
 
 
-static size_t safe_write(int fd, const char *buff, size_t size)
-{
-	size_t todo = size;
-	ssize_t wlen;
-
-	while (todo != 0) {
-		wlen = write(fd, buff, todo);
-		if (wlen > 0) {
-			todo -= wlen;
-			buff += wlen;
-			continue;
-		}
-		else if (wlen < 0) {
-			if ((errno == EINTR) || (errno == EAGAIN)) {
-				continue;
-			}
-			break;
-		}
-		else {
-			/* Undefined behaviour (wlen==0) */
-			errno = EIO;
-			break;
-		}
-	}
-
-	return size - todo;
-}
-
-
 static void format_feed(void *context, char c)
 {
 	size_t res;
@@ -81,7 +54,7 @@ static void format_feed(void *context, char c)
 	if (ctx->n == sizeof(ctx->buff) - 1) {
 		res = (ctx->hType == feed_hStream) ?
 			fwrite(ctx->buff, 1, ctx->n, ctx->h.stream) :
-			safe_write(ctx->h.fd, ctx->buff, ctx->n);
+			__safe_write(ctx->h.fd, ctx->buff, ctx->n);
 
 		ctx->total += res;
 		if (ctx->n != res) {
@@ -152,7 +125,7 @@ int vdprintf(int fd, const char *format, va_list arg)
 	ret = format_parse(&ctx, format_feed, format, arg);
 
 	if ((ret == 0) && (ctx.n != 0)) {
-		res = safe_write(ctx.h.fd, ctx.buff, ctx.n);
+		res = __safe_write(ctx.h.fd, ctx.buff, ctx.n);
 		ctx.total += res;
 
 		if (ctx.n != res) {

unistd/file-internal.h

@@ -0,0 +1,35 @@
+/*
+ * Phoenix-RTOS
+ *
+ * libphoenix
+ *
+ * Internal file operations
+ *
+ * Copyright 2024 Phoenix Systems
+ * Author: Lukasz Leczkowski
+ *
+ * This file is part of Phoenix-RTOS.
+ *
+ * %LICENSE%
+ */
+
+#ifndef _LIBPHOENIX_INTERNAL_FILE_H_
+#define _LIBPHOENIX_INTERNAL_FILE_H_
+
+
+#include <sys/types.h>
+
+
+size_t __safe_write(int fd, const void *buff, size_t size);
+
+
+ssize_t __safe_read(int fd, void *buf, size_t size);
+
+
+int __safe_open(const char *path, int oflag, mode_t mode);
+
+
+int __safe_close(int fd);
+
+
+#endif

unistd/file.c

@@ -48,6 +48,86 @@ WRAP_ERRNO_DEF(int, dup2, (int fildes, int fildes2), (fildes, fildes2))
 WRAP_ERRNO_DEF(int, fsync, (int fildes), (fildes))
 
 
+size_t __safe_write(int fd, const void *buff, size_t size)
+{
+	size_t todo = size;
+	ssize_t wlen;
+	const char *ptr = buff;
+
+	while (todo != 0) {
+		wlen = write(fd, ptr, todo);
+		if (wlen > 0) {
+			todo -= wlen;
+			ptr += wlen;
+			continue;
+		}
+		else if (wlen < 0) {
+			if ((errno == EINTR) || (errno == EAGAIN)) {
+				continue;
+			}
+			break;
+		}
+		else {
+			/* Undefined behaviour (wlen==0) */
+			errno = EIO;
+			break;
+		}
+	}
+
+	return size - todo;
+}
+
+
+ssize_t __safe_read(int fd, void *buf, size_t size)
+{
+	ssize_t rlen;
+	size_t todo = size;
+	char *ptr = buf;
+
+	while (todo > 0) {
+		rlen = read(fd, ptr, todo);
+		if (rlen > 0) {
+			todo -= rlen;
+			ptr += rlen;
+		}
+		else if (rlen == 0) {
+			/* EOF */
+			break;
+		}
+		else if ((errno == EINTR) || (errno == EAGAIN)) {
+			continue;
+		}
+		else {
+			break;
+		}
+	}
+
+	return size - todo;
+}
+
+
+int __safe_open(const char *path, int oflag, mode_t mode)
+{
+	int err;
+	do {
+		err = open(path, oflag, mode);
+	} while ((err < 0) && (errno == EINTR));
+
+	return err;
+}
+
+
+int __safe_close(int fd)
+{
+	int err;
+	do {
+		err = close(fd);
+	} while ((err < 0) && (errno == EINTR));
+
+	return err;
+}
+
+
 off_t lseek(int fildes, off_t offset, int whence)
 {
 	int retval = sys_lseek(fildes, &offset, whence);