[systemd-devel] [PATCH] systemd-bootchart: Prevent leaking file descriptors in open-fdopen combination

[Alexander Sverdlin]

Correctly handle the potential failure of fdopen() (because of OOM, for instance)
after potentially successful open(). Prevent leaking open fd in such case.
---
 src/bootchart/store.c | 12 ++++++++++--
 src/bootchart/svg.c   |  9 +++++++++
 2 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/src/bootchart/store.c b/src/bootchart/store.c
index 3900936..8e9a62f 100644
--- a/src/bootchart/store.c
+++ b/src/bootchart/store.c
@@ -330,9 +330,13 @@ schedstat_next:
                         /* ppid */
                         sprintf(filename, "%d/stat", pid);
                         fd = openat(procfd, filename, O_RDONLY);
+                        if (fd == -1)
+                                continue;
                         st = fdopen(fd, "r");
-                        if (!st)
+                        if (!st) {
+                                close(fd);
                                 continue;
+                        }
                         if (!fscanf(st, "%*s %*s %*s %i", &p)) {
                                 continue;
                         }
@@ -432,9 +436,13 @@ schedstat_next:
                 if (!ps->smaps) {
                         sprintf(filename, "%d/smaps", pid);
                         fd = openat(procfd, filename, O_RDONLY);
+                        if (fd == -1)
+                                continue;
                         ps->smaps = fdopen(fd, "r");
-                        if (!ps->smaps)
+                        if (!ps->smaps) {
+                                close(fd);
                                 continue;
+                        }
                         setvbuf(ps->smaps, smaps_buf, _IOFBF, sizeof(smaps_buf));
                 }
                 else {
diff --git a/src/bootchart/svg.c b/src/bootchart/svg.c
index e1fc531..5412915 100644
--- a/src/bootchart/svg.c
+++ b/src/bootchart/svg.c
@@ -170,6 +170,9 @@ static void svg_title(const char *build) {
                 if (!fgets(cmdline, 255, f))
                         sprintf(cmdline, "Unknown");
                 fclose(f);
+        } else {
+                if (fd >= 0)
+                        close(fd);
         }

         /* extract root fs so we can find disk model name in sysfs */
@@ -185,6 +188,9 @@ static void svg_title(const char *build) {
                         if (!fgets(model, 255, f))
                                 fprintf(stderr, "Error reading disk model for %s\n", rootbdev);
                         fclose(f);
+                } else {
+                        if (fd >= 0)
+                                close(fd);
                 }
         }

@@ -208,6 +214,9 @@ static void svg_title(const char *build) {
                         }
                 }
                 fclose(f);
+        } else {
+                if (fd >= 0)
+                        close(fd);
         }

         svg("<text class=\"t1\" x=\"0\" y=\"30\">Bootchart for %s - %s</text>\n",