utils-std

commit: 5e09cd798fa4bb05eeb642a1788b0c678e3c0363
parent 4b36bf0836473a45d345a98cbeac38291b192a35
Author: Haelwenn (lanodan) Monnier <contact@hacktivis.me>
Date:   Thu, 28 Mar 2024 18:43:58 +0100

cmd/cat: assert(errno == 0)

Diffstat:
M
cmd/cat.c
15
++++++++++++++-

1 file changed, 14 insertions(+), 1 deletion(-)
diff --git a/cmd/cat.c b/cmd/cat.c
@@ -4,7 +4,8 @@
 
 #define _POSIX_C_SOURCE 200809L
 #define _GNU_SOURCE /* splice(2) */
-#include <errno.h>  /* errno */
+#include <assert.h>
+#include <errno.h>
 #include <fcntl.h>  /* open(), O_RDONLY, splice(2) */
 #include <stdint.h> /* SIZE_MAX */
 #include <stdio.h>  /* fprintf(), BUFSIZ */
@@ -17,11 +18,14 @@ concat(int fd, const char *fdname)
 	ssize_t c;
 	char buf[BUFSIZ];
 
+	assert(errno == 0);
 	while((c = read(fd, buf, sizeof(buf))) > 0)
 	{
+		assert(errno == 0);
 		if(write(1, buf, (size_t)c) < 0)
 		{
 			fprintf(stderr, "cat: Error writing: %s\n", strerror(errno));
+			errno = 0;
 			return 1;
 		}
 	}
@@ -29,6 +33,7 @@ concat(int fd, const char *fdname)
 	if(c < 0)
 	{
 		fprintf(stderr, "cat: Error reading ‘%s’: %s\n", fdname, strerror(errno));
+		errno = 0;
 		return 1;
 	}
 
@@ -42,6 +47,7 @@ fd_copy(int fd, const char *fdname)
 	ssize_t c = 0;
 
 again:
+	assert(errno == 0);
 	while((c = splice(
 	           fd, NULL, 1, NULL, SIZE_MAX, SPLICE_F_MOVE | SPLICE_F_NONBLOCK | SPLICE_F_MORE)) > 0)
 		;
@@ -50,13 +56,16 @@ again:
 	{
 		if(errno == EINVAL)
 		{
+			errno = 0;
 			return concat(fd, fdname);
 		}
 		if(errno == EAGAIN)
 		{
+			errno = 0;
 			goto again;
 		}
 		fprintf(stderr, "cat: Error copying ‘%s’: %s\n", fdname, strerror(errno));
+		errno = 0;
 		return 1;
 	}
 
@@ -96,10 +105,12 @@ main(int argc, char *argv[])
 		}
 		else
 		{
+			assert(errno == 0);
 			int fd = open(argv[argi], O_RDONLY);
 			if(fd < 0)
 			{
 				fprintf(stderr, "cat: Error opening ‘%s’: %s\n", argv[argi], strerror(errno));
+				errno = 0;
 				return 1;
 			}
 
@@ -108,9 +119,11 @@ main(int argc, char *argv[])
 				return 1;
 			}
 
+			assert(errno == 0);
 			if(close(fd) < 0)
 			{
 				fprintf(stderr, "cat: Error closing ‘%s’: %s\n", argv[argi], strerror(errno));
+				errno = 0;
 				return 1;
 			}
 		}