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authorRich Felker <dalias@aerifal.cx>2012-03-01 22:08:05 -0500
committerRich Felker <dalias@aerifal.cx>2012-03-01 22:08:05 -0500
commit899b13cae77469a9ed1f076c456b66d567af69d8 (patch)
treea01682acfab764f81abdc08c60ac33320e8fc93a
parent051175d4fe2bdc7b09da9b303e88881ad4f936ff (diff)
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support null buffer argument to getcwd, auto-allocating behavior
this is a popular extension some programs depend on, and by using a
temporary buffer and strdup rather than malloc prior to the syscall,
i've avoided the dependency on free and thus minimized the bloat cost
of supporting this feature.
-rw-r--r--src/unistd/getcwd.c7
1 files changed, 6 insertions, 1 deletions
diff --git a/src/unistd/getcwd.c b/src/unistd/getcwd.c
index b64b560f..2e540cd4 100644
--- a/src/unistd/getcwd.c
+++ b/src/unistd/getcwd.c
@@ -1,8 +1,13 @@
 #include <unistd.h>
 #include <errno.h>
+#include <limits.h>
+#include <string.h>
 #include "syscall.h"
 
 char *getcwd(char *buf, size_t size)
 {
-	return syscall(SYS_getcwd, buf, size) < 0 ? NULL : buf;
+	char tmp[PATH_MAX];
+	if (!buf) buf = tmp, size = PATH_MAX;
+	if (syscall(SYS_getcwd, buf, size) < 0) return 0;
+	return buf == tmp ? strdup(buf) : buf;
 }