Split platform compatibility code into compat.c.

Also use getentropy() in entropy.c, since it should be available in all
platforms.

This also cleaned up the error checking in general.

compat.c

@@ -0,0 +1,62 @@
+#if defined(HAVE_PIPE2) || defined (HAVE_PROG_INVOCATION)
+#define _GNU_SOURCE /* pipe2 or program_invocation_short_name */
+#endif /* HAVE_PIPE2 */
+
+/* pipe_cloexec */
+#include <unistd.h>
+#include <fcntl.h>
+
+/* socket_cloexec */
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <fcntl.h>
+
+/* program_name */
+#include <errno.h>
+#include <stdlib.h>
+
+#include "compat.h"
+
+int pipe_cloexec(int fds[2])
+{
+    #ifdef HAVE_PIPE2
+    // atomic (on newer kernels) application of close-on-exec
+    if (pipe2(fds, O_CLOEXEC) < 0) {
+        return 1;
+    }
+    #else
+    // delayed application of close-on-exec
+    if (pipe(fds) < 0) {
+        return 1;
+    }
+    fcntl(fds[0], F_SETFD, FD_CLOEXEC);
+    fcntl(fds[1], F_SETFD, FD_CLOEXEC);
+    #endif /* HAVE_PIPE2 */
+
+    return 0;
+}
+
+int socket_cloexec(int domain, int type, int protocol)
+{
+    #ifdef HAVE_SOCK_CLOEXEC_H
+    return socket(domain, (type | SOCK_CLOEXEC), protocol);
+    #else
+    int fd = socket(domain, type, protocol);
+    if (fd < 0) {
+        return fd;
+    }
+    fcntl(fd, F_SETFD, FD_CLOEXEC);
+    return fd;
+    #endif /* HAVE_SOCK_CLOEXEC_H */
+}
+
+const char *program_name(void)
+{
+    #ifdef HAVE_PROG_INVOCATION
+    return program_invocation_short_name;
+    #elif HAVE_GETPROGNAME
+    return getprogname();
+    #else
+    #error "no progname impl"
+    #endif /* PROG_INVOCATION & GETPROGNAME */
+}

compat.h

@@ -0,0 +1,8 @@
+#ifndef __COMPAT_H_
+#define __COMPAT_H_
+
+int pipe_cloexec(int [2]);
+int socket_cloexec(int, int, int);
+const char *program_name(void);
+
+#endif // __COMPAT_H_

configure

@@ -5,31 +5,6 @@ ARGS="${CFLAGS} ${LDFLAGS} -x c -o /dev/null -"
 
 printf "" > config.mk
 
-$CC $ARGS <<EOF 2>/dev/null
-#include <sys/random.h>
-int main() {
-	ssize_t (*p)(void *, size_t, unsigned int) = getrandom;
-}
-EOF
-[ $? -eq 0 ] && HAVE_GETRANDOM=yes
-
-$CC $ARGS <<EOF 2>/dev/null
-#include <stdlib.h>
-int main() {
-	void (*p)(void *, size_t) = arc4random_buf;
-}
-EOF
-[ $? -eq 0 ] && HAVE_ARC4RANDOM=yes
-
-echo "HAVE_GETRANDOM:$HAVE_GETRANDOM"
-echo "HAVE_ARC4RANDOM:$HAVE_ARC4RANDOM"
-
-if [ "$HAVE_ARC4RANDOM" ]; then
-	echo "DEFS += -DHAVE_ARC4RANDOM" >> config.mk
-elif [ "$HAVE_GETRANDOM" ]; then
-	echo "DEFS += -DHAVE_GETRANDOM" >> config.mk
-fi
-
 $CC $ARGS <<EOF 2>/dev/null
 #define _GNU_SOURCE /* program_invocation_short_name */
 #include <errno.h>

encrypt.c

@@ -16,6 +16,7 @@
  * expected by the other PurritoBin clients.
  */
 
+#define _DEFAULT_SOURCE /* getentropy */
 #include <stdio.h>
 #include <stdlib.h>
 #include <fcntl.h>
@@ -62,23 +63,15 @@ struct mmap_file encrypt_mmap(struct mmap_file file, uint8_t **keyp, uint8_t **i
         return rv;
     }
 
-    ssize_t err = getrandom(key, KEY_LEN, 0);
-    if (err != KEY_LEN) {
-        fputs("getrandom() error!\n", stderr);
+    if (getentropy(key, KEY_LEN) < 0) {
+        perror("getentropy()");
         return rv;
     }
     #ifdef RANDOMIZE_IV
-    #ifdef HAVE_GETRANDOM
-    err = getrandom(iv, IV_LEN, 0);
-    if (err != IV_LEN) {
-        fputs("getrandom() error!\n", stderr);
+    if (getentropy(iv, IV_LEN) < 0) {
+        perror("getentropy()");
         return rv;
     }
-    #elif HAVE_ARC4RANDOM
-    arc4random_buf(iv, IV_LEN);
-    #else
-    #error "no random buf impl"
-    #endif /* GETRANDOM & ARC4RANDOM */
     memcpy(iv_throwaway, iv, IV_LEN);
     #endif /* RANDOMIZE_IV */
 

makefile

@@ -12,7 +12,7 @@ LDLIBS += -lbearssl
 LDFLAGS += $(CFLAGS) -Wl,--as-needed
 
 PURROBJS = socket.o urls.o files.o comm.o formats.o encrypt.o mmap_file.o
-PURROBJS += read_certs.o gemini.o pager.o
+PURROBJS += read_certs.o gemini.o pager.o compat.o
 
 LIBSOBJS = $(PURROBJS)
 

meson.build

@@ -9,8 +9,6 @@ subdir('po')
 bearssl = compiler.find_library('bearssl', required: true)
 
 gnu_source = '#define _GNU_SOURCE'
-getrandom = compiler.has_header_symbol('sys/random.h', 'getrandom')
-arc4random = compiler.has_header_symbol('stdlib.h', 'arc4random')
 gnu_progname = compiler.has_header_symbol(
   'errno.h',
   'program_invocation_short_name',
@@ -21,13 +19,6 @@ sock_cloexec = compiler.has_header_symbol('sys/socket.h', 'SOCK_CLOEXEC')
 pipe2 = compiler.has_header_symbol('unistd.h', 'pipe2', prefix: gnu_source)
 
 args = []
-if arc4random
-  args += '-DHAVE_ARC4RANDOM'
-elif getrandom
-  args += '-DHAVE_GETRANDOM'
-else
-  error('no random buf impl')
-endif
 if bsd_progname
   args += '-DHAVE_GETPROGNAME'
 elif gnu_progname
@@ -55,6 +46,7 @@ purrlib = static_library(
   'formats.c',
   'encrypt.c',
   'socket.c',
+  'compat.c',
 )
 
 executable('purr', 'purr.c', link_with: purrlib, dependencies: bearssl, install: true)

pager.c

@@ -1,7 +1,4 @@
 #define _POSIX_C_SOURCE 200112L /* fdopen, nanosleep */
-#ifdef HAVE_PIPE2
-#define _GNU_SOURCE /* pipe2 */
-#endif /* HAVE_PIPE2 */
 
 #include <unistd.h>
 #include <stdlib.h>
@@ -10,9 +7,9 @@
 #include <spawn.h>
 #include <time.h>
 #include <sys/wait.h>
-#include <fcntl.h> /* O_CLOEXEC or fcntl */
 
 #include "pager.h"
+#include "compat.h"
 
 int launch_pager(struct pager_proc *p)
 {
@@ -22,20 +19,10 @@ int launch_pager(struct pager_proc *p)
 
     // using close-on-exec here is safe, because fds created by dup don't
     // inherit flags
-    #ifdef HAVE_PIPE2
-    // atomic application of close-on-exec
-    if (pipe2(pipes, O_CLOEXEC) < 0) {
-        perror("pipe2()");
-    }
-    #else
-    // delayed application of close-on-exec
-    if (pipe(pipes) < 0) {
-        perror("pipe()");
+    if (pipe_cloexec(pipes)) {
+        perror("pipe_cloexec()");
         return rv;
     }
-    fcntl(pipes[0], F_SETFD, FD_CLOEXEC);
-    fcntl(pipes[1], F_SETFD, FD_CLOEXEC);
-    #endif /* HAVE_PIPE2 */
 
     char *pager = getenv("PAGER");
     if (pager == NULL || *pager == 0) {

purr.c

@@ -1,10 +1,4 @@
 #define _POSIX_C_SOURCE 200112L /* getopt */
-
-#ifdef HAVE_PROG_INVOCATION
-#define _GNU_SOURCE /* program_invocation_short_name */
-#include <errno.h>
-#endif /* HAVE_PROG_INVOCATION */
-
 #include <signal.h>
 #include <stdbool.h>
 #include <stdio.h>
@@ -14,28 +8,27 @@
 #include <bearssl.h>
 
 #include "purr.h"
+#include "compat.h"
 #include "mmap_file.h"
 #include "read_certs.h"
 #include "translation.h"
 
-const char *progname;
-
 __attribute__ ((noreturn))
 static void usage(bool fail)
 {
     char *proghelp;
-    if (strcmp(progname, "meow") == 0) {
+    if (strcmp(program_name(), "meow") == 0) {
         proghelp = _(
             "Usage: meow [options] <file>\n"
             "    send <file> in encrypted format\n");
-    } else if (strcmp(progname, "meowd") == 0) {
+    } else if (strcmp(program_name(), "meowd") == 0) {
         proghelp = _(
             "Usage meowd [options] <url>\n"
             "    receive encrypted file from <url>\n");
     } else {
-       proghelp = _(
-           "Usage: purr [options] <action> <file>|<url>\n"
-           "    action: s[end] | r[ecv]\n");
+        proghelp = _(
+            "Usage: purr [options] <action> <file>|<url>\n"
+            "    action: s[end] | r[ecv]\n");
     }
 
     FILE *stream = fail ? stderr : stdout;
@@ -71,21 +64,13 @@ int main (int argc, char **argv)
     bindtextdomain(GETTEXT_PACKAGE, GETTEXT_DIR);
     textdomain(GETTEXT_PACKAGE);
 
-    #ifdef HAVE_PROG_INVOCATION
-    progname = program_invocation_short_name;
-    #elif HAVE_GETPROGNAME
-    progname = getprogname();
-    #else
-    #error "no progname impl"
-    #endif /* PROG_INVOCATION & GETPROGNAME */
-
     // check program name:
     // symlinks to original program with special behavior
-    if (strcmp(progname, "meow") == 0) {
+    if (strcmp(program_name(), "meow") == 0) {
         // encrypted send mode
         send = true;
         encrypt = true;
-    } else if (strcmp(progname, "meowd") == 0) {
+    } else if (strcmp(program_name(), "meowd") == 0) {
         // encrypted recv mode
         recv = true;
         encrypt = true;

urls.c

@@ -3,28 +3,18 @@
 #include <unistd.h>
 #include <stdlib.h>
 
-#ifndef HAVE_SOCK_CLOEXEC_H
-#include <fcntl.h>
-#endif /* HAVE_SOCK_CLOEXEC_H */
-
 #include <arpa/inet.h>
 #include <netdb.h>
 #include <netinet/in.h>
 #include <sys/socket.h>
 
 #include "purr.h"
+#include "compat.h"
 #include "translation.h"
 
 #define MAX_DOMAIN_LEN 254
 #define MAX_SHORTY_LEN 16
 
-/* enable atomic close-on-exec for socket */
-#ifdef HAVE_SOCK_CLOEXEC_H
-#define SOCKET_FLAG SOCK_CLOEXEC
-#else
-#define SOCKET_FLAG 0
-#endif /* HAVE_SOCK_CLOEXEC_H */
-
 static const char *http_sch = "http://";
 static const char *https_sch = "https://";
 static const char *gemini_sch = "gemini://";
@@ -215,14 +205,11 @@ int host_connect(const char *host, const char *port, bool debug)
         if (debug) fprintf(stderr, "%s: %s\n", _("IP address"), ip_addr);
 
         // try to establish connection
-        fd = socket(p->ai_family, p->ai_socktype | SOCKET_FLAG, p->ai_protocol);
+        fd = socket_cloexec(p->ai_family, p->ai_socktype, p->ai_protocol);
         if (fd < 0) {
-            perror("socket()");
+            perror("socket_cloexec()");
             continue;
         }
-        #ifndef HAVE_SOCK_CLOEXEC_H
-        fcntl(fd, F_SETFD, FD_CLOEXEC);
-        #endif /* HAVE_SOCK_CLOEXEC_H */
 
         if (connect(fd, p->ai_addr, p->ai_addrlen) < 0) {
             // connect errors can be caused server-side