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authorJim Meyering <jim@meyering.net>2002-12-02 08:11:45 +0000
committerJim Meyering <jim@meyering.net>2002-12-02 08:11:45 +0000
commit7570cb86a6787dbbc1ab750e19581a2186012302 (patch)
tree717e78e3df8711e05c83707da2a65aead7a0adcb
parentc9c5c4c3e15229732fafeba9210ea3d34c4e61dd (diff)
downloadcoreutils-7570cb86a6787dbbc1ab750e19581a2186012302.tar.xz
(EINTR): Define.
(safe_read): Rewrite to loop IFF read fails with EINTR.
-rw-r--r--lib/safe-read.c45
1 files changed, 18 insertions, 27 deletions
diff --git a/lib/safe-read.c b/lib/safe-read.c
index 75ac7bf31..527653c5c 100644
--- a/lib/safe-read.c
+++ b/lib/safe-read.c
@@ -57,41 +57,32 @@ extern int errno;
Tru64 5.1. */
#define MAX_BYTES_TO_READ INT_MAX
+#ifndef EINTR
+/* If a system doesn't have support for EINTR, define it
+ to be a value to which errno will never be set. */
+# define EINTR (INT_MAX - 10)
+#endif
+
/* Read up to COUNT bytes at BUF from descriptor FD, retrying if interrupted.
Return the actual number of bytes read, zero for EOF, or SAFE_READ_ERROR
upon error. */
size_t
safe_read (int fd, void *buf, size_t count)
{
- size_t total_read = 0;
- char *ptr = buf;
+ size_t nbytes_to_read = count;
+ ssize_t result;
- while (count > 0)
+ /* Limit the number of bytes to read, to avoid running
+ into unspecified behaviour. But keep the file pointer block
+ aligned when doing so. */
+ if (nbytes_to_read > MAX_BYTES_TO_READ)
+ nbytes_to_read = MAX_BYTES_TO_READ & ~8191;
+
+ do
{
- size_t nbytes_to_read = count;
- ssize_t result;
-
- /* Limit the number of bytes to read in one round, to avoid running
- into unspecified behaviour. But keep the file pointer block
- aligned when doing so. */
- if (nbytes_to_read > MAX_BYTES_TO_READ)
- nbytes_to_read = MAX_BYTES_TO_READ & ~8191;
-
- result = read (fd, ptr, nbytes_to_read);
- if (result == 0)
- break;
- if (result < 0)
- {
-#ifdef EINTR
- if (errno == EINTR)
- continue;
-#endif
- return SAFE_READ_ERROR;
- }
- total_read += result;
- ptr += result;
- count -= result;
+ result = read (fd, buf, nbytes_to_read);
}
+ while (result < 0 && errno == EINTR);
- return total_read;
+ return (size_t) result;
}