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first ever correct use of strncpy

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This commit is contained in:
rsc 2007-08-24 21:00:02 +00:00
parent aa6824ab64
commit 766ba5cc06
3 changed files with 17 additions and 24 deletions
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1
defs.h
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@ -127,6 +127,7 @@ void* memset(void*, int, uint);
char* safestrcpy(char*, const char*, int);
int strlen(const char*);
int strncmp(const char*, const char*, uint);
char* strncpy(char*, const char*, int);
// syscall.c
int argint(int, int*);

24
fs.c
View file

@ -455,15 +455,7 @@ writei(struct inode *ip, char *src, uint off, uint n)
int
namecmp(const char *s, const char *t)
{
int i;
for(i=0; i<DIRSIZ; i++){
if(s[i] != t[i])
return s[i] - t[i];
if(s[i] == 0)
break;
}
return 0;
return strncmp(s, t, DIRSIZ);
}
// Look for a directory entry in a directory.
@ -500,18 +492,6 @@ dirlookup(struct inode *dp, char *name, uint *poff)
return 0;
}
// Copy one name to another.
static void
namecpy(char *s, const char *t)
{
int i;
for(i=0; i<DIRSIZ && t[i]; i++)
s[i] = t[i];
for(; i<DIRSIZ; i++)
s[i] = 0;
}
// Write a new directory entry (name, ino) into the directory dp.
int
dirlink(struct inode *dp, char *name, uint ino)
@ -534,7 +514,7 @@ dirlink(struct inode *dp, char *name, uint ino)
break;
}
namecpy(de.name, name);
strncpy(de.name, name, DIRSIZ);
de.inum = ino;
if(writei(dp, (char*)&de, off, sizeof(de)) != sizeof(de))
panic("dirwrite");

16
string.c
View file

@ -56,8 +56,20 @@ strncmp(const char *p, const char *q, uint n)
n--, p++, q++;
if(n == 0)
return 0;
else
return (int) ((uchar) *p - (uchar) *q);
return (uchar)*p - (uchar)*q;
}
char*
strncpy(char *s, const char *t, int n)
{
char *os;
os = s;
while(n-- > 0 && (*s++ = *t++) != 0)
;
while(n-- > 0)
*s++ = 0;
return os;
}
// Like strncpy but guaranteed to NUL-terminate.