tests: Check return values of write() and dup2().

tests/example.c

@@ -25,6 +25,7 @@
 #include <errno.h>
 
 #include "../src/compiler.h"
+#include "example.h"
 
 
 int main(int argc, char **argv unused) {
@@ -35,22 +36,21 @@ int main(int argc, char **argv unused) {
     errno = ENOMEM;
     perror("error!");
 
-    write(STDERR_FILENO, "write to stderr 2", 17);
-    write(STDOUT_FILENO, "write to stdout 2", 17);
+    xwrite(STDERR_FILENO, "write to stderr 2", 17);
+    xwrite(STDOUT_FILENO, "write to stdout 2", 17);
 
     fprintf(stderr, "\n");
     fprintf(stdout, "\n");
     fflush(stdout);
 
-    /* Check usage of tracked_fds_list (at least in parts). No error checking
-     * here! */
-    dup2(STDERR_FILENO, 471);
-    dup2(471, 42);
-    write(471, "more on stderr\n", 15);
+    /* Check usage of tracked_fds_list (at least in parts). */
+    xdup2(STDERR_FILENO, 471);
+    xdup2(471, 42);
+    xwrite(471, "more on stderr\n", 15);
     close(471);
-    dup2(STDOUT_FILENO, 471);
-    write(42, "stderr ...\n", 11);
-    write(471, "more on stdout\n", 15);
+    xdup2(STDOUT_FILENO, 471);
+    xwrite(42, "stderr ...\n", 11);
+    xwrite(471, "more on stdout\n", 15);
 
     /* Glibc uses __overflow() for this ... */
     putc_unlocked('x', stderr);

tests/example.h

@@ -36,3 +36,22 @@
         } \
         fflush(stdout); \
     } else
+
+static ssize_t xwrite(int fd, void const *buf, size_t count) {
+    ssize_t result = write(fd, buf, count);
+    if (result == -1) {
+        perror("write");
+        exit(EXIT_FAILURE);
+    }
+    /* Ignore short writes here. Doesn't matter for test cases. */
+    return result;
+}
+
+static int xdup2(int oldfd, int newfd) {
+    int result = dup2(oldfd, newfd);
+    if (result == -1) {
+        perror("dup2");
+        exit(EXIT_FAILURE);
+    }
+    return result;
+}

tests/example_exec.c

@@ -27,6 +27,7 @@
 #include <string.h>
 #include <unistd.h>
 
+#include "example.h"
 #include "../src/compiler.h"
 
 
@@ -123,7 +124,7 @@ int main(int argc unused, char **argv) {
         printf("\nCHECKING COLORING.\n\n");
         fflush(stdout);
 
-        dup2(2, 3);
+        xdup2(2, 3);
 
         char *args[] = { argv0, NULL };
         char *envp[] = { ldpreload, NULL };
@@ -131,24 +132,24 @@ int main(int argc unused, char **argv) {
         execve(argv[0], args, envp);
         return EXIT_FAILURE;
     } else if (!skip--) {
-        dup2(2, 4);
+        xdup2(2, 4);
 
         execl(argv[0], argv0, NULL);
         return EXIT_FAILURE;
     } else if (!skip--) {
-        dup2(2, 5);
+        xdup2(2, 5);
 
         execlp(argv[0], argv0, NULL);
         return EXIT_FAILURE;
     } else if (!skip--) {
-        dup2(2, 6);
+        xdup2(2, 6);
 
         char *envp[] = { ldpreload, NULL };
 
         execle(argv[0], argv0, NULL, envp);
         return EXIT_FAILURE;
     } else if (!skip--) {
-        dup2(2, 7);
+        xdup2(2, 7);
 
         /* Test closing a few descriptors. */
         close(5);
@@ -159,7 +160,7 @@ int main(int argc unused, char **argv) {
         execv(argv[0], args);
         return EXIT_FAILURE;
     } else if (!skip--) {
-        dup2(2, 8);
+        xdup2(2, 8);
 
         /* And a few more. */
         close(7);
@@ -177,7 +178,7 @@ int main(int argc unused, char **argv) {
         close(3);
         close(8);
 
-        dup2(2, 5);
+        xdup2(2, 5);
 
         char *args[] = { argv0, NULL };
         char *envp[] = { ldpreload, "COLORED_STDERR_FDS=5,", NULL };
@@ -188,7 +189,7 @@ int main(int argc unused, char **argv) {
         char *args[] = { argv0, NULL };
         char *envp[] = { ldpreload, NULL };
 
-        dup2(5, 6);
+        xdup2(5, 6);
         close(5);
 
         execve(argv[0], args, envp);