journal-remote: implement %m support in mhd_respondf

errno value is not protected (it is undefined after this function returns).
Various mhd_* functions are not documented to protect errno, so this could not
guaranteed anyway.

4 files changed, 23 insertions, 19 deletions

diff --git a/src/journal-remote/journal-gatewayd.c b/src/journal-remote/journal-gatewayd.c
index c2b5a5f205..05e9b7253a 100644
--- a/src/journal-remote/journal-gatewayd.c
+++ b/src/journal-remote/journal-gatewayd.c
@@ -475,7 +475,7 @@ static int request_handler_entries(
 
         r = open_journal(m);
         if (r < 0)
-                return mhd_respondf(connection, MHD_HTTP_INTERNAL_SERVER_ERROR, "Failed to open journal: %s\n", strerror(-r));
+                return mhd_respondf(connection, r, MHD_HTTP_INTERNAL_SERVER_ERROR, "Failed to open journal: %m\n");
 
         if (request_parse_accept(m, connection) < 0)
                 return mhd_respond(connection, MHD_HTTP_BAD_REQUEST, "Failed to parse Accept header.\n");
@@ -633,7 +633,7 @@ static int request_handler_fields(
 
         r = open_journal(m);
         if (r < 0)
-                return mhd_respondf(connection, MHD_HTTP_INTERNAL_SERVER_ERROR, "Failed to open journal: %s\n", strerror(-r));
+                return mhd_respondf(connection, r, MHD_HTTP_INTERNAL_SERVER_ERROR, "Failed to open journal: %m\n");
 
         if (request_parse_accept(m, connection) < 0)
                 return mhd_respond(connection, MHD_HTTP_BAD_REQUEST, "Failed to parse Accept header.\n");
@@ -699,10 +699,10 @@ static int request_handler_file(
 
         fd = open(path, O_RDONLY|O_CLOEXEC);
         if (fd < 0)
-                return mhd_respondf(connection, MHD_HTTP_NOT_FOUND, "Failed to open file %s: %m\n", path);
+                return mhd_respondf(connection, errno, MHD_HTTP_NOT_FOUND, "Failed to open file %s: %m\n", path);
 
         if (fstat(fd, &st) < 0)
-                return mhd_respondf(connection, MHD_HTTP_INTERNAL_SERVER_ERROR, "Failed to stat file: %m\n");
+                return mhd_respondf(connection, errno, MHD_HTTP_INTERNAL_SERVER_ERROR, "Failed to stat file: %m\n");
 
         response = MHD_create_response_from_fd_at_offset64(st.st_size, fd, 0);
         if (!response)
@@ -766,15 +766,15 @@ static int request_handler_machine(
 
         r = open_journal(m);
         if (r < 0)
-                return mhd_respondf(connection, MHD_HTTP_INTERNAL_SERVER_ERROR, "Failed to open journal: %s\n", strerror(-r));
+                return mhd_respondf(connection, r, MHD_HTTP_INTERNAL_SERVER_ERROR, "Failed to open journal: %m\n");
 
         r = sd_id128_get_machine(&mid);
         if (r < 0)
-                return mhd_respondf(connection, MHD_HTTP_INTERNAL_SERVER_ERROR, "Failed to determine machine ID: %s\n", strerror(-r));
+                return mhd_respondf(connection, r, MHD_HTTP_INTERNAL_SERVER_ERROR, "Failed to determine machine ID: %m\n");
 
         r = sd_id128_get_boot(&bid);
         if (r < 0)
-                return mhd_respondf(connection, MHD_HTTP_INTERNAL_SERVER_ERROR, "Failed to determine boot ID: %s\n", strerror(-r));
+                return mhd_respondf(connection, r, MHD_HTTP_INTERNAL_SERVER_ERROR, "Failed to determine boot ID: %m\n");
 
         hostname = gethostname_malloc();
         if (!hostname)
@@ -782,11 +782,11 @@ static int request_handler_machine(
 
         r = sd_journal_get_usage(m->journal, &usage);
         if (r < 0)
-                return mhd_respondf(connection, MHD_HTTP_INTERNAL_SERVER_ERROR, "Failed to determine disk usage: %s\n", strerror(-r));
+                return mhd_respondf(connection, r, MHD_HTTP_INTERNAL_SERVER_ERROR, "Failed to determine disk usage: %s\n");
 
         r = sd_journal_get_cutoff_realtime_usec(m->journal, &cutoff_from, &cutoff_to);
         if (r < 0)
-                return mhd_respondf(connection, MHD_HTTP_INTERNAL_SERVER_ERROR, "Failed to determine disk usage: %s\n", strerror(-r));
+                return mhd_respondf(connection, r, MHD_HTTP_INTERNAL_SERVER_ERROR, "Failed to determine disk usage: %s\n");
 
         if (parse_env_file("/etc/os-release", NEWLINE, "PRETTY_NAME", &os_name, NULL) == -ENOENT)
                 (void) parse_env_file("/usr/lib/os-release", NEWLINE, "PRETTY_NAME", &os_name, NULL);
diff --git a/src/journal-remote/journal-remote.c b/src/journal-remote/journal-remote.c
index 80e2adb100..a3884f574a 100644
--- a/src/journal-remote/journal-remote.c
+++ b/src/journal-remote/journal-remote.c
@@ -524,13 +524,12 @@ static int process_http_upload(
                         log_warning("Failed to process data for connection %p", connection);
                         if (r == -E2BIG)
                                 return mhd_respondf(connection,
-                                                    MHD_HTTP_REQUEST_ENTITY_TOO_LARGE,
-                                                    "Entry is too large, maximum is %u bytes.\n",
-                                                    DATA_SIZE_MAX);
+                                                    r, MHD_HTTP_REQUEST_ENTITY_TOO_LARGE,
+                                                    "Entry is too large, maximum is " STRINGIFY(DATA_SIZE_MAX) " bytes.\n");
                         else
                                 return mhd_respondf(connection,
-                                                    MHD_HTTP_UNPROCESSABLE_ENTITY,
-                                                    "Processing failed: %s.", strerror(-r));
+                                                    r, MHD_HTTP_UNPROCESSABLE_ENTITY,
+                                                    "Processing failed: %m.");
                 }
         }
 
@@ -541,8 +540,9 @@ static int process_http_upload(
 
         remaining = source_non_empty(source);
         if (remaining > 0) {
-                log_warning("Premature EOFbyte. %zu bytes lost.", remaining);
-                return mhd_respondf(connection, MHD_HTTP_EXPECTATION_FAILED,
+                log_warning("Premature EOF byte. %zu bytes lost.", remaining);
+                return mhd_respondf(connection,
+                                    0, MHD_HTTP_EXPECTATION_FAILED,
                                     "Premature EOF. %zu bytes of trailing data not processed.",
                                     remaining);
         }
@@ -623,8 +623,7 @@ static int request_handler(
         if (r == -ENOMEM)
                 return respond_oom(connection);
         else if (r < 0)
-                return mhd_respond(connection, MHD_HTTP_INTERNAL_SERVER_ERROR,
-                                   strerror(-r));
+                return mhd_respondf(connection, r, MHD_HTTP_INTERNAL_SERVER_ERROR, "%m");
 
         hostname = NULL;
         return MHD_YES;
diff --git a/src/journal-remote/microhttpd-util.c b/src/journal-remote/microhttpd-util.c
index 2f16b02e9a..67d97e24ff 100644
--- a/src/journal-remote/microhttpd-util.c
+++ b/src/journal-remote/microhttpd-util.c
@@ -82,6 +82,7 @@ int mhd_respond_oom(struct MHD_Connection *connection) {
 }
 
 int mhd_respondf(struct MHD_Connection *connection,
+                 int error,
                  enum MHD_RequestTerminationCode code,
                  const char *format, ...) {
 
@@ -92,6 +93,9 @@ int mhd_respondf(struct MHD_Connection *connection,
         assert(connection);
         assert(format);
 
+        if (error < 0)
+                error = -error;
+        errno = -error;
         va_start(ap, format);
         r = vasprintf(&m, format, ap);
         va_end(ap);
diff --git a/src/journal-remote/microhttpd-util.h b/src/journal-remote/microhttpd-util.h
index ea160f212b..af26ab69fe 100644
--- a/src/journal-remote/microhttpd-util.h
+++ b/src/journal-remote/microhttpd-util.h
@@ -39,8 +39,9 @@ void microhttpd_logger(void *arg, const char *fmt, va_list ap) _printf_(2, 0);
 #define respond_oom(connection) log_oom(), mhd_respond_oom(connection)
 
 int mhd_respondf(struct MHD_Connection *connection,
+                 int error,
                  unsigned code,
-                 const char *format, ...) _printf_(3,4);
+                 const char *format, ...) _printf_(4,5);
 
 int mhd_respond(struct MHD_Connection *connection,
                 unsigned code,