Implement pbcopy and pbpaste in C

Ted Unangst broke my netcat implementation of pbpaste with this commit:
<https://github.com/openbsd/src/commit/bb978d8>, which, when /dev/null
is attached to stdin, causes nc to exit and never read from the socket.

Turns out the core functionality of netcat can be implemented in about
50 lines of C.

1 files changed, 52 insertions, 0 deletions

diff --git a/.bin/pbcopy.c b/.bin/pbcopy.c
new file mode 100755
index 00000000..37c334ca
--- /dev/null
+++ b/.bin/pbcopy.c
@@ -0,0 +1,52 @@
+#if 0
+cc -Wall -Wextra -pedantic $@ -o $(dirname $0)/pbcopy $0 && \
+exec cc -Wall -Wextra -pedantic -DPBPASTE $@ -o $(dirname $0)/pbpaste $0
+#endif
+
+#include <arpa/inet.h>
+#include <err.h>
+#include <stdio.h>
+#include <sys/socket.h>
+#include <sysexits.h>
+#include <unistd.h>
+
+int main() {
+    int error;
+
+    int client = socket(PF_INET, SOCK_STREAM, 0);
+    if (client < 0) err(EX_OSERR, "socket");
+
+    struct sockaddr_in addr = {
+        .sin_family = AF_INET,
+        .sin_port = htons(7062),
+        .sin_addr = { .s_addr = htonl(0x7f000001) },
+    };
+
+    error = connect(client, (struct sockaddr *)&addr, sizeof(addr));
+    if (error) err(EX_OSERR, "connect");
+
+#ifdef PBPASTE
+    int fdIn = client;
+    int fdOut = STDOUT_FILENO;
+    error = shutdown(client, SHUT_WR);
+    if (error) err(EX_OSERR, "shutdown");
+#else
+    int fdIn = STDIN_FILENO;
+    int fdOut = client;
+#endif
+
+    char readBuf[4096];
+    ssize_t readLen;
+    while (0 < (readLen = read(fdIn, readBuf, sizeof(readBuf)))) {
+        char *writeBuf = readBuf;
+        ssize_t writeLen;
+        while (0 < (writeLen = write(fdOut, writeBuf, readLen))) {
+            writeBuf += writeLen;
+            readLen -= writeLen;
+        }
+        if (writeLen < 0) err(EX_IOERR, "write");
+    }
+    if (readLen < 0) err(EX_IOERR, "read");
+
+    return 0;
+}