xref: /inferno-os/libkern/strstr.c (revision 37da2899f40661e3e9631e497da8dc59b971cbd0) 
1 #include <lib9.h>
2 
3 /*
4  * Return pointer to first occurrence of s2 in s1,
5  * 0 if none
6  */
7 char*
strstr(char * s1,char * s2)8 strstr(char *s1, char *s2)
9 {
10 	char *p;
11 	int f, n;
12 
13 	f = s2[0];
14 	if(f == 0)
15 		return s1;
16 	n = strlen(s2);
17 	for(p=strchr(s1, f); p; p=strchr(p+1, f))
18 		if(strncmp(p, s2, n) == 0)
19 			return p;
20 	return 0;
21 }
22