diff options
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/exec.c | 1 | ||||
| -rw-r--r-- | kernel/fs.c | 38 |
2 files changed, 30 insertions, 9 deletions
diff --git a/kernel/exec.c b/kernel/exec.c index d62d29d..09b4bdc 100644 --- a/kernel/exec.c +++ b/kernel/exec.c @@ -65,6 +65,7 @@ exec(char *path, char **argv) uint64 oldsz = p->sz; // Allocate two pages at the next page boundary. + // Make the first inaccessible as a stack guard. // Use the second as the user stack. sz = PGROUNDUP(sz); uint64 sz1; diff --git a/kernel/fs.c b/kernel/fs.c index 53a3a0f..247a86f 100644 --- a/kernel/fs.c +++ b/kernel/fs.c @@ -61,6 +61,7 @@ bzero(int dev, int bno) // Blocks. // Allocate a zeroed disk block. +// returns 0 if out of disk space. static uint balloc(uint dev) { @@ -82,7 +83,8 @@ balloc(uint dev) } brelse(bp); } - panic("balloc: out of blocks"); + printf("balloc: out of blocks\n"); + return 0; } // Free a disk block. @@ -374,6 +376,7 @@ iunlockput(struct inode *ip) // Return the disk block address of the nth block in inode ip. // If there is no such block, bmap allocates one. +// returns 0 if out of disk space. static uint bmap(struct inode *ip, uint bn) { @@ -381,21 +384,32 @@ bmap(struct inode *ip, uint bn) struct buf *bp; if(bn < NDIRECT){ - if((addr = ip->addrs[bn]) == 0) - ip->addrs[bn] = addr = balloc(ip->dev); + if((addr = ip->addrs[bn]) == 0){ + addr = balloc(ip->dev); + if(addr == 0) + return 0; + ip->addrs[bn] = addr; + } return addr; } bn -= NDIRECT; if(bn < NINDIRECT){ // Load indirect block, allocating if necessary. - if((addr = ip->addrs[NDIRECT]) == 0) - ip->addrs[NDIRECT] = addr = balloc(ip->dev); + if((addr = ip->addrs[NDIRECT]) == 0){ + addr = balloc(ip->dev); + if(addr == 0) + return 0; + ip->addrs[NDIRECT] = addr; + } bp = bread(ip->dev, addr); a = (uint*)bp->data; if((addr = a[bn]) == 0){ - a[bn] = addr = balloc(ip->dev); - log_write(bp); + addr = balloc(ip->dev); + if(addr){ + a[bn] = addr; + log_write(bp); + } } brelse(bp); return addr; @@ -464,7 +478,10 @@ readi(struct inode *ip, int user_dst, uint64 dst, uint off, uint n) n = ip->size - off; for(tot=0; tot<n; tot+=m, off+=m, dst+=m){ - bp = bread(ip->dev, bmap(ip, off/BSIZE)); + uint addr = bmap(ip, off/BSIZE); + if(addr == 0) + break; + bp = bread(ip->dev, addr); m = min(n - tot, BSIZE - off%BSIZE); if(either_copyout(user_dst, dst, bp->data + (off % BSIZE), m) == -1) { brelse(bp); @@ -495,7 +512,10 @@ writei(struct inode *ip, int user_src, uint64 src, uint off, uint n) return -1; for(tot=0; tot<n; tot+=m, off+=m, src+=m){ - bp = bread(ip->dev, bmap(ip, off/BSIZE)); + uint addr = bmap(ip, off/BSIZE); + if(addr == 0) + break; + bp = bread(ip->dev, addr); m = min(n - tot, BSIZE - off%BSIZE); if(either_copyin(bp->data + (off % BSIZE), user_src, src, m) == -1) { brelse(bp); |