utils-std

commit: 1dbb6e53be5452d9901879d96b611bafabec550f
parent 8ee8d7b92bfdda109c83d24151c468a487ab0a8d
Author: Haelwenn (lanodan) Monnier <contact@hacktivis.me>
Date:   Fri, 27 Sep 2024 10:18:32 +0200

cmd/head: use auto_fd_copy

Diffstat:
M
Makefile
4
++--
M
cmd/head.c
49
++++++++-----------------------------------------

2 files changed, 10 insertions(+), 43 deletions(-)
diff --git a/Makefile b/Makefile
@@ -154,9 +154,9 @@ cmd/truncate: cmd/truncate.c lib/truncation.c lib/truncation.h Makefile
 	$(RM) -f ${<:=.gcov} ${@:=.gcda} ${@:=.gcno}
 	$(CC) -std=c99 $(CFLAGS) -o $@ cmd/truncate.c lib/truncation.c $(LDFLAGS) $(LDSTATIC)
 
-cmd/head: cmd/head.c lib/truncation.c lib/truncation.h Makefile
+cmd/head: cmd/head.c lib/truncation.c lib/truncation.h lib/fs.c lib/fs.h Makefile
 	$(RM) -f ${<:=.gcov} ${@:=.gcda} ${@:=.gcno}
-	$(CC) -std=c99 $(CFLAGS) -o $@ cmd/head.c lib/truncation.c $(LDFLAGS) $(LDSTATIC)
+	$(CC) -std=c99 $(CFLAGS) -o $@ cmd/head.c lib/truncation.c lib/fs.c $(LDFLAGS) $(LDSTATIC)
 
 cmd/split: cmd/split.c lib/truncation.c lib/truncation.h lib/fs.c lib/fs.h Makefile
 	$(RM) -f ${<:=.gcov} ${@:=.gcda} ${@:=.gcno}
diff --git a/cmd/head.c b/cmd/head.c
@@ -4,6 +4,7 @@
 
 #define _POSIX_C_SOURCE 200809L
 
+#include "../lib/fs.h"         // auto_fd_copy
 #include "../lib/truncation.h" // apply_size_suffix
 
 #include <assert.h>
@@ -15,8 +16,6 @@
 #include <string.h> // strerror
 #include <unistd.h> // read
 
-#define MIN(a, b) (((a) < (b)) ? (a) : (b))
-
 static const char *header_fmt = "==> %s <==\n";
 
 const char *argv0 = "head";
@@ -32,20 +31,6 @@ int delim = '\n';
 static int
 copy_bytes(const char *filename)
 {
-	if(buflen == 0)
-	{
-		// Note: de-allocated in main()
-		buf = malloc(BUFSIZ);
-
-		if(buf == NULL)
-		{
-			fprintf(stderr, "%s: error: Failed to allocate buffer: %s\n", argv0, strerror(errno));
-			return 1;
-		}
-
-		buflen = BUFSIZ;
-	}
-
 	int fd = -1;
 	if(filename[0] == '-' && filename[1] == 0)
 	{
@@ -63,32 +48,14 @@ copy_bytes(const char *filename)
 	}
 
 	int err = 0;
-
-	for(size_t i = 0; i < bytes;)
+	if(auto_fd_copy(fd, STDOUT_FILENO, bytes) < 0)
 	{
-		ssize_t nread = read(fd, buf, MIN(buflen, bytes - i));
-		if(nread < 0)
-		{
-			fprintf(
-			    stderr, "%s: error: Failed reading file '%s': %s\n", argv0, filename, strerror(errno));
-			err = 1;
-			break;
-		}
-
-		if(nread == 0) break;
-
-		if(write(STDOUT_FILENO, buf, nread) < 0)
-		{
-			fprintf(stderr,
-			        "%s: error: Failed writing line from '%s' to stdout: %s\n",
-			        argv0,
-			        filename,
-			        strerror(errno));
-			err = 1;
-			break;
-		}
-
-		i += nread;
+		fprintf(stderr,
+		        "%s: error: Failed copying data from '%s' to <stdout>: %s\n",
+		        argv0,
+		        filename,
+		        strerror(errno));
+		err = 1;
 	}
 
 	if(fd != STDIN_FILENO)