GopherProxy

	tAdd searchpath(). - plan9port - [fork] Plan 9 from user space
	git clone git://src.adamsgaard.dk/plan9port
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	---
	commit 4a6237114063e9cc3d7a3b544f9477d93738c1a0
	parent 28125cbd4c7d937278d838f1e375ee0763019d0d
	Author: rsc <devnull@localhost>
	Date: Sun, 23 Jan 2005 22:33:59 +0000

	Add searchpath().

	Diffstat:
	M include/libc.h \| 1 +
	M src/lib9/mkfile \| 1 +
	A src/lib9/searchpath.c \| 62 +++++++++++++++++++++++++++++…

	3 files changed, 64 insertions(+), 0 deletions(-)
	---
	diff --git a/include/libc.h b/include/libc.h
	t@@ -390,6 +390,7 @@ extern int postnote(int, int, char *);
	extern double p9pow10(int);
	/* extern int putenv(char, char); <stdlib.h. */
	/* extern void qsort(void, long, long, int ()(void, void)); …
	+extern char* searchpath(char*);
	/* extern int p9setjmp(p9jmp_buf); */
	#define p9setjmp(b) sigsetjmp((void*)(b), 1)
	/*
	diff --git a/src/lib9/mkfile b/src/lib9/mkfile
	t@@ -131,6 +131,7 @@ LIB9OFILES=\
	read9pmsg.$O\
	readn.$O\
	rfork.$O\
	+ searchpath.$O\
	seek.$O\
	sendfd.$O\
	sleep.$O\
	diff --git a/src/lib9/searchpath.c b/src/lib9/searchpath.c
	t@@ -0,0 +1,62 @@
	+#include <u.h>
	+#include <libc.h>
	+
	+/*
	+ * Search $PATH for an executable with the given name.
	+ * Like in rc, mid-name slashes do not disable search.
	+ * Should probably handle escaped colons,
	+ * but I don't know what the syntax is.
	+ */
	+char*
	+searchpath(char *name)
	+{
	+ char path, p, *next;
	+ char s, ss;
	+ int ns, l;
	+
	+ s = nil;
	+ ns = 0;
	+ if((name[0] == '.' && name[1] == '/')
	+ \|\| (name[0] == '.' && name[1] == '.' && name[2] == '/')
	+ \|\| (name[0] == '/')){
	+ if(access(name, AEXEC) >= 0)
	+ return strdup(name);
	+ return nil;
	+ }
	+
	+ path = getenv("PATH");
	+ for(p=path; p && *p; p=next){
	+ if((next = strchr(p, ':')) != nil)
	+ *next++ = 0;
	+ if(*p == 0){
	+ if(access(name, AEXEC) >= 0){
	+ free(s);
	+ free(path);
	+ return strdup(name);
	+ }
	+ }else{
	+ l = strlen(p)+1+strlen(name)+1;
	+ if(l > ns){
	+ ss = realloc(s, l);
	+ if(ss == nil){
	+ free(s);
	+ free(path);
	+ return nil;
	+ }
	+ s = ss;
	+ ns = l;
	+ }
	+ strcpy(s, p);
	+ strcat(s, "/");
	+ strcat(s, name);
	+ if(access(s, AEXEC) >= 0){
	+ free(path);
	+ return s;
	+ }
	+ }
	+ }
	+ free(s);
	+ free(path);
	+ return nil;
	+}
	+