* [PATCH] libfile: implement new pread_full
@ 2022-03-18 14:49 Ahmad Fatoum
2022-03-28 8:56 ` Sascha Hauer
0 siblings, 1 reply; 2+ messages in thread
From: Ahmad Fatoum @ 2022-03-18 14:49 UTC (permalink / raw)
To: barebox; +Cc: Ahmad Fatoum
We already have pwrite_full, add pread_full for symmetry.
Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
---
include/libfile.h | 1 +
lib/libfile.c | 25 +++++++++++++++++++++++++
2 files changed, 26 insertions(+)
diff --git a/include/libfile.h b/include/libfile.h
index 3c2fe1714dcb..a353ccfa9ea9 100644
--- a/include/libfile.h
+++ b/include/libfile.h
@@ -2,6 +2,7 @@
#ifndef __LIBFILE_H
#define __LIBFILE_H
+int pread_full(int fd, void *buf, size_t size, loff_t offset);
int pwrite_full(int fd, const void *buf, size_t size, loff_t offset);
int write_full(int fd, const void *buf, size_t size);
int read_full(int fd, void *buf, size_t size);
diff --git a/lib/libfile.c b/lib/libfile.c
index 6b373f05ca72..1f533133c593 100644
--- a/lib/libfile.c
+++ b/lib/libfile.c
@@ -75,6 +75,31 @@ int write_full(int fd, const void *buf, size_t size)
}
EXPORT_SYMBOL(write_full);
+/*
+ * pread_full - read to filedescriptor at offset
+ *
+ * Like pread, but this function only returns less bytes than
+ * requested when the end of file is reached.
+ */
+int pread_full(int fd, void *buf, size_t size, loff_t offset)
+{
+ size_t insize = size;
+ int now;
+
+ while (size) {
+ now = pread(fd, buf, size, offset);
+ if (now == 0)
+ break;
+ if (now < 0)
+ return now;
+ size -= now;
+ buf += now;
+ }
+
+ return insize - size;
+}
+EXPORT_SYMBOL(pread_full);
+
/*
* read_full - read from filedescriptor
*
--
2.30.2
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^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH] libfile: implement new pread_full
2022-03-18 14:49 [PATCH] libfile: implement new pread_full Ahmad Fatoum
@ 2022-03-28 8:56 ` Sascha Hauer
0 siblings, 0 replies; 2+ messages in thread
From: Sascha Hauer @ 2022-03-28 8:56 UTC (permalink / raw)
To: Ahmad Fatoum; +Cc: barebox
On Fri, Mar 18, 2022 at 03:49:42PM +0100, Ahmad Fatoum wrote:
> We already have pwrite_full, add pread_full for symmetry.
>
> Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
> ---
> include/libfile.h | 1 +
> lib/libfile.c | 25 +++++++++++++++++++++++++
> 2 files changed, 26 insertions(+)
Applied, thanks
Sascha
>
> diff --git a/include/libfile.h b/include/libfile.h
> index 3c2fe1714dcb..a353ccfa9ea9 100644
> --- a/include/libfile.h
> +++ b/include/libfile.h
> @@ -2,6 +2,7 @@
> #ifndef __LIBFILE_H
> #define __LIBFILE_H
>
> +int pread_full(int fd, void *buf, size_t size, loff_t offset);
> int pwrite_full(int fd, const void *buf, size_t size, loff_t offset);
> int write_full(int fd, const void *buf, size_t size);
> int read_full(int fd, void *buf, size_t size);
> diff --git a/lib/libfile.c b/lib/libfile.c
> index 6b373f05ca72..1f533133c593 100644
> --- a/lib/libfile.c
> +++ b/lib/libfile.c
> @@ -75,6 +75,31 @@ int write_full(int fd, const void *buf, size_t size)
> }
> EXPORT_SYMBOL(write_full);
>
> +/*
> + * pread_full - read to filedescriptor at offset
> + *
> + * Like pread, but this function only returns less bytes than
> + * requested when the end of file is reached.
> + */
> +int pread_full(int fd, void *buf, size_t size, loff_t offset)
> +{
> + size_t insize = size;
> + int now;
> +
> + while (size) {
> + now = pread(fd, buf, size, offset);
> + if (now == 0)
> + break;
> + if (now < 0)
> + return now;
> + size -= now;
> + buf += now;
> + }
> +
> + return insize - size;
> +}
> +EXPORT_SYMBOL(pread_full);
> +
> /*
> * read_full - read from filedescriptor
> *
> --
> 2.30.2
>
>
> _______________________________________________
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> http://lists.infradead.org/mailman/listinfo/barebox
>
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