git: 3abcc79c6a25 - main - head: use getline() instead of fgetln()

The branch main has been updated by imp:

URL: https://cgit.FreeBSD.org/src/commit/?id=3abcc79c6a25fe9846be5a036d9a44086fb00163

commit 3abcc79c6a25fe9846be5a036d9a44086fb00163
Author:     Martin Tournoij <martin@arp242.net>
AuthorDate: 2024-04-19 21:11:30 +0000
Commit:     Warner Losh <imp@FreeBSD.org>
CommitDate: 2024-04-19 21:52:22 +0000

    head: use getline() instead of fgetln()
    
    This replaces fgetln() with getline(). The main reason for this is
    portability, making things easier for people who want to compile these
    tools on non-FreeBSD systems.
    
    I appreciate that's probably not the top concern for FreeBSD base tools,
    but fgetln() is impossible to port to most platforms, as concurrent
    access is essentially impossible to implement fully correct without the
    line buffer on the FILE struct. Other than this, many generic FreeBSD
    tools compile fairly cleanly on Linux with a few small changes.
    
    Most uses of fgetln() pre-date getline() support (added in 2009 with
    69099ba2ec8b), and there's been some previous patches (ee3ca711a898
    8c98e6b1a7f3 1a2a4fc8ce1b) for other tools.
    
    Obtained from:  https://github.com/dcantrell/bsdutils and
                    https://github.com/chimera-linux/chimerautils
    Signed-off-by: Martin Tournoij <martin@arp242.net>
    Reviewed by: imp
    Pull Request: https://github.com/freebsd/freebsd-src/pull/893
---
 usr.bin/head/head.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/usr.bin/head/head.c b/usr.bin/head/head.c
index 598d54b1c1ed..62796ae144a1 100644
--- a/usr.bin/head/head.c
+++ b/usr.bin/head/head.c
@@ -156,12 +156,13 @@ main(int argc, char *argv[])
 static void
 head(FILE *fp, intmax_t cnt)
 {
-	char *cp;
-	size_t error, readlen;
+	char *cp = NULL;
+	size_t error, bufsize = 0;
+	ssize_t readlen;
 
-	while (cnt != 0 && (cp = fgetln(fp, &readlen)) != NULL) {
+	while (cnt != 0 && (readlen = getline(&cp, &bufsize, fp)) >= 0) {
 		error = fwrite(cp, sizeof(char), readlen, stdout);
-		if (error != readlen)
+		if ((ssize_t)error != readlen)
 			err(1, "stdout");
 		cnt--;
 	}