Properly print errors from system() in archive and restore commands

We used to assume that the only errors which could happen were ones
which set the errno, but that is not the case. We also want to give nice
output on non-zero return values and if the process was killed by a
signal.

contrib/pg_tde/src/bin/pg_tde_archive_decrypt.c

@@ -146,6 +146,7 @@ main(int argc, char *argv[])
 	char		tmpdir[MAXPGPATH] = TMPFS_DIRECTORY "/pg_tde_archiveXXXXXX";
 	char		tmppath[MAXPGPATH];
 	bool		issegment;
+	int			rc;
 
 	pg_logging_init(argv[0]);
 	progname = get_progname(argv[0]);
@@ -208,9 +209,22 @@ main(int argc, char *argv[])
 		command = replace_percent_placeholders(command,
 											   "ARCHIVE-COMMAND", "fp",
 											   targetname, sourcepath);
+	rc = system(command);
 
-	if (system(command) != 0)
+	if (rc != 0)
-		pg_fatal("ARCHIVE-COMMAND \"%s\" failed: %m", command);
+	{
+		if (rc == -1)
+			pg_fatal("ARCHIVE-COMMAND \"%s\" failed: %m", command);
+		else if (WIFEXITED(rc))
+			pg_fatal("ARCHIVE-COMMAND \"%s\" failed with exit code %d",
+					 command, WEXITSTATUS(rc));
+		else if (WIFSIGNALED(rc))
+			pg_fatal("ARCHIVE-COMMAND \"%s\" was terminated by signal %d: %s",
+					 command, WTERMSIG(rc), pg_strsignal(WTERMSIG(rc)));
+		else
+			pg_fatal("ARCHIVE-COMMAND \"%s\" exited with unrecognized status %d",
+					 command, rc);
+	}
 
 	free(command);
 

contrib/pg_tde/src/bin/pg_tde_restore_encrypt.c

@@ -141,6 +141,7 @@ main(int argc, char *argv[])
 	char		tmpdir[MAXPGPATH] = TMPFS_DIRECTORY "/pg_tde_restoreXXXXXX";
 	char		tmppath[MAXPGPATH];
 	bool		issegment;
+	int			rc;
 
 	pg_logging_init(argv[0]);
 	progname = get_progname(argv[0]);
@@ -201,9 +202,22 @@ main(int argc, char *argv[])
 		command = replace_percent_placeholders(command,
 											   "RESTORE-COMMAND", "fp",
 											   sourcename, targetpath);
+	rc = system(command);
 
-	if (system(command) != 0)
+	if (rc != 0)
-		pg_fatal("RESTORE-COMMAND \"%s\" failed: %m", command);
+	{
+		if (rc == -1)
+			pg_fatal("RESTORE-COMMAND \"%s\" failed: %m", command);
+		else if (WIFEXITED(rc))
+			pg_fatal("RESTORE-COMMAND \"%s\" failed with exit code %d",
+					 command, WEXITSTATUS(rc));
+		else if (WIFSIGNALED(rc))
+			pg_fatal("RESTORE-COMMAND \"%s\" was terminated by signal %d: %s",
+					 command, WTERMSIG(rc), pg_strsignal(WTERMSIG(rc)));
+		else
+			pg_fatal("RESTORE-COMMAND \"%s\" exited with unrecognized status %d",
+					 command, rc);
+	}
 
 	free(command);