libmount: rewrite mountinfo/fstab parsers to use sscanf()

The old solution (without scanf()) was based on old code from
mount(8). It seems that the modern libc is able to provide all
necessary functionality by sscanf() and %ms directive.

Signed-off-by: Karel Zak <kzak@redhat.com>

diff --git a/include/mangle.h b/include/mangle.h
index 0ccd37768c2eb320aeb0cc9fceda3c1d9ab0dd8a..5dda902f7c433dfc0ee5532de6dbbdbdf2b73959 100644 (file)
--- a/include/mangle.h
+++ b/include/mangle.h
@@ -10,5 +10,10 @@ extern char *mangle(const char *s);
 extern void unmangle_to_buffer(const char *s, char *buf, size_t len);
 extern char *unmangle(const char *s);
 
+static inline void unmangle_string(char *s)
+{
+       unmangle_to_buffer(s, s, strlen(s) + 1);
+}
+
 #endif /* UTIL_LINUX_MANGLE_H */
 

diff --git a/lib/mangle.c b/lib/mangle.c
index e320cfb7c63f9db8027cb3815780102697c8004c..938dd8e55e311c7b0366e91d110ff03e5a622671 100644 (file)
--- a/lib/mangle.c
+++ b/lib/mangle.c
@@ -115,10 +115,19 @@ int main(int argc, char *argv[])
 
        else if (!strcmp(argv[1], "--unmangle")) {
                char *x = unmangle(argv[2]);
-               if (x)
+
+               if (x) {
                        printf("unmangled: '%s'\n", x);
-               else
-                       err(EXIT_FAILURE, "unmangle failed");
+                       free(x);
+               }
+
+               x = strdup(argv[2]);
+               unmangle_to_buffer(x, x, strlen(x) + 1);
+
+               if (x) {
+                       printf("self-unmangled: '%s'\n", x);
+                       free(x);
+               }
        }
 
        return EXIT_SUCCESS;

diff --git a/shlibs/mount/src/tab_parse.c b/shlibs/mount/src/tab_parse.c
index 062b9040ec671bea7bf8c1daf7b590797c71d944..603908f203314ea3fb794b80c17918c602effe0e 100644 (file)
--- a/shlibs/mount/src/tab_parse.c
+++ b/shlibs/mount/src/tab_parse.c
@@ -29,138 +29,44 @@ static inline char *skip_spaces(char *s)
        return s;
 }
 
-static inline char *skip_nonspaces(char *s)
-{
-       assert(s);
-
-       while (*s && !(*s == ' ' || *s == '\t'))
-               s++;
-       return s;
-}
-
-static size_t next_word_size(char *s, char **start, char **end)
-{
-       char *e;
-
-       assert(s);
-
-       s = skip_spaces(s);
-       if (!*s)
-               return 0;
-       e = skip_nonspaces(s);
-
-       if (start)
-               *start = s;
-       if (end)
-               *end = e;
-
-       return e - s;
-}
-
-static int next_word(char **s, char **next)
-{
-       size_t sz;
-       char *end;
-
-       assert(s);
-
-       sz = next_word_size(*s, s, &end) + 1;
-       if (sz == 1)
-               return -EINVAL;
-
-       *next = malloc(sz);
-       if (!*next)
-               return -ENOMEM;
-
-       unmangle_to_buffer(*s, *next, sz);
-       *s = end + 1;
-       return 0;
-}
-
-static int next_word_skip(char **s)
-{
-       *s = skip_spaces(*s);
-       if (!**s)
-               return -EINVAL;
-       *s = skip_nonspaces(*s);
-       return 0;
-}
-
-static int next_number(char **s, int *num)
-{
-       char *end = NULL;
-
-       assert(num);
-       assert(s);
-
-       *s = skip_spaces(*s);
-       if (!**s)
-               return -EINVAL;
-
-       *num = strtol(*s, &end, 10);
-       if (end == NULL || *s == end)
-               return -EINVAL;
-
-       *s = end;
-
-       /* valid end of number is space or terminator */
-       if (*end == ' ' || *end == '\t' || *end == '\0')
-               return 0;
-
-       return -EINVAL;
-}
-
 /*
  * Parses one line from {fs,m}tab
  */
 static int mnt_tab_parse_file_line(mnt_fs *fs, char *s)
 {
-       int rc = 0, col;
-
-       fs->passno = fs->freq = 0;      /* default */
-
-       for (col = 0; rc == 0 && col < 4; col++) {
-               char *p = NULL;
-
-               rc = next_word(&s, &p);
-               if (rc)
-                       goto done;
-
-               switch(col) {
-               /* SOURCE */
-               case 0:
-                       rc =__mnt_fs_set_source_ptr(fs, p);
-                       break;
-               /* TARGET */
-               case 1:
-                       fs->target = p;
-                       break;
-               /* TYPE */
-               case 2:
-                       rc = __mnt_fs_set_fstype_ptr(fs, p);
-                       break;
-               /* OPTS */
-               case 3:
-                       rc = __mnt_fs_set_optstr_ptr(fs, p, TRUE);
-                       break;
-               }
-               if (rc) {
-                       free(p);
-                       goto done;
-               }
+       int rc;
+       char *src, *fstype, *optstr;
+
+       rc = sscanf(s,  "%ms "  /* (1) source */
+                       "%ms "  /* (2) target */
+                       "%ms "  /* (3) FS type */
+                       "%ms "  /* (4) options */
+                       "%u "   /* (5) freq */
+                       "%u ",  /* (6) passno */
+
+                       &src,
+                       &fs->target,
+                       &fstype,
+                       &optstr,
+                       &fs->freq,
+                       &fs->passno);
+
+       if (rc >= 4 && rc <= 6) {
+               unmangle_string(src);
+               unmangle_string(fs->target);
+               unmangle_string(fstype);
+               unmangle_string(optstr);
+
+               rc = __mnt_fs_set_source_ptr(fs, src);
+               if (!rc)
+                       rc = __mnt_fs_set_fstype_ptr(fs, fstype);
+               if (!rc)
+                       rc = __mnt_fs_set_optstr_ptr(fs, optstr, TRUE);
+       } else {
+               DBG(TAB, mnt_debug( "parse error: [field=%d]: '%s'", rc, s));
+               rc = -EINVAL;
        }
 
-       /* FREQ (optional) */
-       rc = next_number(&s, &fs->freq);
-       if (rc && !*s)
-               rc = 0;         /* no error, end of line, freq is optional */
-
-       else {
-               rc = next_number(&s, &fs->passno);
-               if (rc && !*s)
-                       rc = 0;
-       }
-done:
        return rc;
 }
 
@@ -169,85 +75,55 @@ done:
  */
 static int mnt_parse_mountinfo_line(mnt_fs *fs, char *s)
 {
-       int rc = 0, col;
+       int rc;
        unsigned int maj, min;
-       char *p = NULL;
-
-       /* ID */
-       rc = next_number(&s, &fs->id);
-       if (rc)
-               goto done;
-
-       /* PARENT */
-       rc = next_number(&s, &fs->parent);
-       if (rc)
-               goto done;
-
-       /* <maj>:<min> */
-       s = skip_spaces(s);
-       if (!*s || sscanf(s, "%u:%u", &maj, &min) != 2)
-               rc = -EINVAL;
-       else {
+       char *fstype, *src;
+
+       rc = sscanf(s,  "%u "           /* (1) id */
+                       "%u "           /* (2) parent */
+                       "%u:%u "        /* (3) maj:min */
+                       "%ms "          /* (4) mountroot */
+                       "%ms "          /* (5) target */
+                       "%ms"           /* (6) vfs options (fs-independent) */
+                       "%*[^-]"        /* (7) optional fields */
+                       "- "            /* (8) separator */
+                       "%ms "          /* (9) FS type */
+                       "%ms "          /* (10) source */
+                       "%ms",          /* (11) fs options (fs specific) */
+
+                       &fs->id,
+                       &fs->parent,
+                       &maj, &min,
+                       &fs->root,
+                       &fs->target,
+                       &fs->vfs_optstr,
+                       &fstype,
+                       &src,
+                       &fs->fs_optstr);
+
+       if (rc == 10) {
                fs->devno = makedev(maj, min);
-               next_word_skip(&s);
-       }
-
-       for (col = 3; rc == 0 && col < 9; col++) {
-               rc = next_word(&s, &p);
-               if (rc)
-                       break;
-
-               switch(col) {
-               /* MOUNTROOT */
-               case 3:
-                       fs->root = p;
-                       break;
-
-               /* TARGET (mountpoit) */
-               case 4:
-                       fs->target = p;
-                       break;
-
-               /* OPTIONS (fs-independent) */
-               case 5:
-                       fs->vfs_optstr = p;
-
-                       /* ignore optional fields behind options */
-                       do {
-                               s = skip_spaces(s);
-                               if (s && *s == '-' &&
-                                   (*(s + 1) == ' ' || *(s + 1) == '\t')) {
-                                       s++;
-                                       break;
-                               }
-                               next_word_skip(&s);
-                       } while (s);
-                       break;
 
-               /* FSTYPE */
-               case 6:
-                       rc =__mnt_fs_set_fstype_ptr(fs, p);
-                       break;
+               unmangle_string(fs->root);
+               unmangle_string(fs->target);
+               unmangle_string(fs->vfs_optstr);
+               unmangle_string(fstype);
 
-               /* SOURCE or "none" */
-               case 7:
-                       rc = __mnt_fs_set_source_ptr(fs, p);
-                       break;
+               if (!strcmp(src, "none")) {
+                       free(src);
+                       src = NULL;
+               } else
+                       unmangle_string(src);
 
-               /* OPTIONS (fs-dependent) */
-               case 8:
-                       fs->fs_optstr = p;
+               unmangle_string(fs->fs_optstr);
 
-                       if (!strcmp(fs->fs_optstr, "none")) {
-                               free(fs->fs_optstr);
-                               fs->fs_optstr = NULL;
-                       }
-                       break;
-               }
+               rc = __mnt_fs_set_fstype_ptr(fs, fstype);
+               if (!rc)
+                       rc = __mnt_fs_set_source_ptr(fs, src);
+       } else {
+               DBG(TAB, mnt_debug("parse error [field=%d]: '%s'", rc, s));
+               rc = -EINVAL;
        }
-       if (rc)
-               free(p);
-done:
        return rc;
 }
 
@@ -258,17 +134,10 @@ done:
  */
 static int detect_fmt(char *line)
 {
-       int num;
-
-       /* ID */
-       if (next_number(&line, &num) != 0)
-               return MNT_FMT_FSTAB;
-
-       /* PARENT */
-       if (next_number(&line, &num) != 0)
-               return MNT_FMT_FSTAB;
+       unsigned int a, b;
 
-       return MNT_FMT_MOUNTINFO;
+       return sscanf(line, "%u %u", &a, &b) == 2 ?
+                       MNT_FMT_MOUNTINFO : MNT_FMT_FSTAB;
 }
 
 
@@ -374,12 +243,10 @@ static int mnt_tab_parse_next(mnt_tab *tb, FILE *f, mnt_fs *fs,
                tb->fmt = detect_fmt(s);
 
        if (tb->fmt == MNT_FMT_FSTAB) {
-               /* parse /etc/{fs,m}tab */
                if (mnt_tab_parse_file_line(fs, s) != 0)
                        goto err;
 
        } else if (tb->fmt == MNT_FMT_MOUNTINFO) {
-               /* parse /proc/self/mountinfo */
                if (mnt_parse_mountinfo_line(fs, s) != 0)
                        goto err;
        }