improve error handling in mntent stuff...

[musl] / src / linux / mntent.c

diff --git a/src/linux/mntent.c b/src/linux/mntent.c
index e373566..f151625 100644 (file)
--- a/src/linux/mntent.c
+++ b/src/linux/mntent.c
@@ -1,6 +1,7 @@
 #include <stdio.h>
 #include <string.h>
 #include <mntent.h>
+#include <errno.h>
 
 FILE *setmntent(const char *name, const char *mode)
 {
@@ -13,39 +14,50 @@ int endmntent(FILE *f)
        return 1;
 }
 
-struct mntent *getmntent(FILE *f)
+struct mntent *getmntent_r(FILE *f, struct mntent *mnt, char *linebuf, int buflen)
 {
-       static char linebuf[256];
-       static struct mntent mnt;
        int cnt, n[8];
 
-       mnt.mnt_freq = 0;
-       mnt.mnt_passno = 0;
+       mnt->mnt_freq = 0;
+       mnt->mnt_passno = 0;
 
        do {
-               fgets(linebuf, sizeof linebuf, f);
-               if (feof(f)) return NULL;
+               fgets(linebuf, buflen, f);
+               if (feof(f) || ferror(f)) return 0;
+               if (!strchr(linebuf, '\n')) {
+                       if (fseeko(f, -(off_t)strlen(linebuf), SEEK_CUR))
+                               fscanf(f, "%*[^\n]%*[\n]");
+                       errno = ERANGE;
+                       return 0;
+               }
                cnt = sscanf(linebuf, " %n%*s%n %n%*s%n %n%*s%n %n%*s%n %d %d",
                        n, n+1, n+2, n+3, n+4, n+5, n+6, n+7,
-                       &mnt.mnt_freq, &mnt.mnt_passno);
-       } while (cnt >= 8 && linebuf[n[0]] != '#');
+                       &mnt->mnt_freq, &mnt->mnt_passno);
+       } while (cnt < 2 || linebuf[n[0]] == '#');
 
        linebuf[n[1]] = 0;
        linebuf[n[3]] = 0;
        linebuf[n[5]] = 0;
        linebuf[n[7]] = 0;
 
-       mnt.mnt_fsname = linebuf+n[0];
-       mnt.mnt_dir = linebuf+n[2];
-       mnt.mnt_type = linebuf+n[4];
-       mnt.mnt_opts = linebuf+n[6];
+       mnt->mnt_fsname = linebuf+n[0];
+       mnt->mnt_dir = linebuf+n[2];
+       mnt->mnt_type = linebuf+n[4];
+       mnt->mnt_opts = linebuf+n[6];
+
+       return mnt;
+}
 
-       return &mnt;
+struct mntent *getmntent(FILE *f)
+{
+       static char linebuf[256];
+       static struct mntent mnt;
+       return getmntent_r(f, &mnt, linebuf, sizeof linebuf);
 }
 
 int addmntent(FILE *f, const struct mntent *mnt)
 {
-       fseek(f, 0, SEEK_END);
+       if (fseek(f, 0, SEEK_END)) return 1;
        return fprintf(f, "%s\t%s\t%s\t%s\t%d\t%d\n",
                mnt->mnt_fsname, mnt->mnt_dir, mnt->mnt_type, mnt->mnt_opts,
                mnt->mnt_freq, mnt->mnt_passno) < 0;