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authorRich Felker <dalias@aerifal.cx>2012-10-24 21:16:06 -0400
committerRich Felker <dalias@aerifal.cx>2012-10-24 21:16:06 -0400
commit892cafff665b44d238e3b664f61ca38dd965cba6 (patch)
treec65353fe88b0d78025e113b77ed8728a2b4bc8d4 /src
parent708c91f4e9be2cfd6d35e71361956e13f3201b85 (diff)
downloadmusl-892cafff665b44d238e3b664f61ca38dd965cba6.tar.gz
greatly improve freopen behavior
1. don't open /dev/null just as a basis to copy flags; use shared __fmodeflags function to get the right file flags for the mode. 2. handle the case (probably invalid, but whatever) case where the original stream's file descriptor was closed; previously, the logic re-closed it. 3. accept the "e" mode flag for close-on-exec; update dup3 to fallback to using dup2 so we can simply call __dup3 instead of putting fallback logic in freopen itself.
Diffstat (limited to 'src')
-rw-r--r--src/internal/stdio_impl.h1
-rw-r--r--src/stdio/__fmodeflags.c16
-rw-r--r--src/stdio/fopen.c9
-rw-r--r--src/stdio/freopen.c17
-rw-r--r--src/unistd/dup3.c15
5 files changed, 41 insertions, 17 deletions
diff --git a/src/internal/stdio_impl.h b/src/internal/stdio_impl.h
index 65dcfbda..279e91fd 100644
--- a/src/internal/stdio_impl.h
+++ b/src/internal/stdio_impl.h
@@ -87,6 +87,7 @@ size_t __fwritex(const unsigned char *, size_t, FILE *);
int __putc_unlocked(int, FILE *);
FILE *__fdopen(int, const char *);
+int __fmodeflags(const char *);
#define OFLLOCK() LOCK(libc.ofl_lock)
#define OFLUNLOCK() UNLOCK(libc.ofl_lock)
diff --git a/src/stdio/__fmodeflags.c b/src/stdio/__fmodeflags.c
new file mode 100644
index 00000000..da9f23b6
--- /dev/null
+++ b/src/stdio/__fmodeflags.c
@@ -0,0 +1,16 @@
+#include <fcntl.h>
+#include <string.h>
+
+int __fmodeflags(const char *mode)
+{
+ int flags;
+ if (strchr(mode, '+')) flags = O_RDWR;
+ else if (*mode == 'r') flags = O_RDONLY;
+ else flags = O_WRONLY;
+ if (strchr(mode, 'x')) flags |= O_EXCL;
+ if (strchr(mode, 'e')) flags |= O_CLOEXEC;
+ if (*mode != 'r') flags |= O_CREAT;
+ if (*mode == 'w') flags |= O_TRUNC;
+ if (*mode == 'a') flags |= O_APPEND;
+ return flags;
+}
diff --git a/src/stdio/fopen.c b/src/stdio/fopen.c
index 03c10cd1..c741aede 100644
--- a/src/stdio/fopen.c
+++ b/src/stdio/fopen.c
@@ -13,14 +13,7 @@ FILE *fopen(const char *restrict filename, const char *restrict mode)
}
/* Compute the flags to pass to open() */
- if (strchr(mode, '+')) flags = O_RDWR;
- else if (*mode == 'r') flags = O_RDONLY;
- else flags = O_WRONLY;
- if (strchr(mode, 'x')) flags |= O_EXCL;
- if (strchr(mode, 'e')) flags |= O_CLOEXEC;
- if (*mode != 'r') flags |= O_CREAT;
- if (*mode == 'w') flags |= O_TRUNC;
- if (*mode == 'a') flags |= O_APPEND;
+ flags = __fmodeflags(mode);
fd = syscall_cp(SYS_open, filename, flags|O_LARGEFILE, 0666);
if (fd < 0) return 0;
diff --git a/src/stdio/freopen.c b/src/stdio/freopen.c
index 5b4f126d..c80ce3b4 100644
--- a/src/stdio/freopen.c
+++ b/src/stdio/freopen.c
@@ -7,24 +7,27 @@
/* Locking is not necessary because, in the event of failure, the stream
* passed to freopen is invalid as soon as freopen is called. */
+int __dup3(int, int, int);
+
FILE *freopen(const char *restrict filename, const char *restrict mode, FILE *restrict f)
{
- int fl;
+ int fl = __fmodeflags(mode);
FILE *f2;
fflush(f);
if (!filename) {
- f2 = fopen("/dev/null", mode);
- if (!f2) goto fail;
- fl = __syscall(SYS_fcntl, f2->fd, F_GETFL, 0);
+ if (fl&O_CLOEXEC)
+ __syscall(SYS_fcntl, f->fd, F_SETFD, FD_CLOEXEC);
+ fl &= ~(O_CREAT|O_EXCL|O_CLOEXEC);
if (syscall(SYS_fcntl, f->fd, F_SETFL, fl) < 0)
- goto fail2;
+ goto fail;
+ return f;
} else {
f2 = fopen(filename, mode);
if (!f2) goto fail;
- if (syscall(SYS_dup2, f2->fd, f->fd) < 0)
- goto fail2;
+ if (f2->fd == f->fd) f2->fd = -1; /* avoid closing in fclose */
+ else if (__dup3(f2->fd, f->fd, fl&O_CLOEXEC)<0) goto fail2;
}
f->flags = (f->flags & F_PERM) | f2->flags;
diff --git a/src/unistd/dup3.c b/src/unistd/dup3.c
index 18f6fcce..1f7134b3 100644
--- a/src/unistd/dup3.c
+++ b/src/unistd/dup3.c
@@ -1,10 +1,21 @@
#define _GNU_SOURCE
#include <unistd.h>
#include <errno.h>
+#include <fcntl.h>
#include "syscall.h"
+#include "libc.h"
-int dup3(int old, int new, int flags) {
+int __dup3(int old, int new, int flags)
+{
int r;
- while ((r=__syscall(SYS_dup3, old, new, flags))==-EBUSY);
+ if (old==new) return __syscall_ret(-EINVAL);
+ if (flags & O_CLOEXEC) {
+ while ((r=__syscall(SYS_dup3, old, new, flags))==-EBUSY);
+ if (r!=-ENOSYS) return __syscall_ret(r);
+ }
+ while ((r=__syscall(SYS_dup2, old, new))==-EBUSY);
+ if (flags & O_CLOEXEC) __syscall(SYS_fcntl, new, F_SETFD, FD_CLOEXEC);
return __syscall_ret(r);
}
+
+weak_alias(__dup3, dup3);