Bionic: Implementing mount table entry functions

Change-Id: I84c13ee86e939e53b07ea149c9dffe726ff4da01

2 files changed, 131 insertions, 2 deletions

diff --git a/libc/bionic/stubs.c b/libc/bionic/stubs.c
index d4956747d..4e711e809 100644
--- a/libc/bionic/stubs.c
+++ b/libc/bionic/stubs.c
@@ -37,6 +37,8 @@
 #include <errno.h>
 #include <ctype.h>
 
+#define MNTENT_LENGTH_MAX 400    //Buffer size for one record in mount entry file
+
 /** Thread-specific state for the stubs functions
  **/
 
@@ -51,6 +53,9 @@ typedef struct {
     char           group_name_buffer[32];
 } stubs_state_t;
 
+static struct mntent *mnt = NULL;
+char mntent_buf[MNTENT_LENGTH_MAX];    //Buffer to hold a record in mount entry file
+
 static void
 stubs_state_free( void*  _s )
 {
@@ -351,8 +356,129 @@ void endpwent(void)
 
 struct mntent* getmntent(FILE* f)
 {
-    fprintf(stderr, "FIX ME! implement getmntent() %s:%d\n", __FILE__, __LINE__);
-    return NULL;
+    int index = 0, i = 0, flag = 1;
+    char ch;
+    char *temp;
+    //Keeping count so that we don't over run the buffer size
+    int count = MNTENT_LENGTH_MAX;
+
+    if(mnt == NULL)
+        if(!(mnt = (struct mntent *)malloc(sizeof(struct mntent))))
+            return NULL;
+
+    mnt->mnt_fsname = mntent_buf;
+
+    if(f->_read(f->_cookie, &ch, 1) != 1)
+        return NULL;
+
+    // There are exactly 6 columns per record and so
+    // we are checking value of index against 6 here.
+    while(ch && (index < 6) && count) {
+        switch(index) {
+            case 0:
+                //Storing mounted device.
+                if(ch != ' ') {
+                    mnt->mnt_fsname[i++] = ch;
+                }
+                else {
+                    mnt->mnt_fsname[i++] = '\0';
+                    mnt->mnt_dir =  &(mnt->mnt_fsname[i]);
+                    i = 0;
+                    index++;
+                }
+                count--;
+                break;
+            case 1:
+                //Storing mount point.
+                if(ch != ' ') {
+                    mnt->mnt_dir[i++] = ch;
+                }
+                else {
+                    mnt->mnt_dir[i++] = '\0';
+                    mnt->mnt_type =  &(mnt->mnt_dir[i]);
+                    i = 0;
+                    index++;
+                }
+                count--;
+                break;
+            case 2:
+                //Storing file system type.
+                if(ch != ' ') {
+                    mnt->mnt_type[i++] = ch;
+                }
+                else {
+                    mnt->mnt_type[i++] = '\0';
+                    mnt->mnt_opts =  &(mnt->mnt_type[i]);
+                    i = 0;
+                    index++;
+                }
+                count--;
+                break;
+            case 3:
+                //Storing mount options.
+                if(ch != ' ') {
+                    mnt->mnt_opts[i++] = ch;
+                }
+                else {
+                    mnt->mnt_opts[i++] = '\0';
+                    temp =  &(mnt->mnt_opts[i]);
+                    i = 0;
+                    index++;
+                }
+                count--;
+                break;
+            case 4:
+                //Dummy value to match the format of /etc/mtab
+                if(ch != ' ') {
+                    temp[i++] = ch;
+                }
+                else {
+                    temp[i++] = '\0';
+                    mnt->mnt_freq = atoi(temp);
+                    temp = &(temp[i]);
+                    i = 0;
+                    index++;
+                }
+                count--;
+                break;
+            case 5:
+                //Dummy value to match the format of /etc/mtab
+                if(ch != '\n') {
+                    temp[i++] = ch;
+                }
+                else {
+                    temp[i++] = '\0';
+                    mnt->mnt_passno = atoi(temp);
+                    temp = &(temp[i]);
+                    i = 0;
+                    index++;
+                    flag = 0;
+                }
+                count--;
+                break;
+        }
+        if (flag)
+            f->_read(f->_cookie, &ch, 1);
+    }
+    if(!count && flag)
+        return NULL;
+
+    return mnt;
+}
+
+FILE* setmntent(const char *filename, const char *type)
+{
+    return fopen(filename,  type);
+}
+
+int endmntent(FILE* f)
+{
+    if(mnt) {
+        free(mnt);
+        mnt = NULL;
+    }
+    f->_close(f);
+    return 1;
 }
 
 char* ttyname(int fd)
diff --git a/libc/include/mntent.h b/libc/include/mntent.h
index b83da1f2f..d7fcf0a77 100644
--- a/libc/include/mntent.h
+++ b/libc/include/mntent.h
@@ -45,9 +45,12 @@ struct mntent
 
 __BEGIN_DECLS
 
+FILE *setmntent(const char *, const char *);
 
 struct mntent* getmntent(FILE*);
 
+int endmntent(FILE*);
+
 __END_DECLS
 
 #endif