Re: [PATCH/WIP 1/8] wrapper: implement xopen()
From: Torsten Bögershausen <hidden>
Date: 2016-06-15 23:05:01
On 2015-05-27 15.33, Paul Tan wrote:
quoted hunk ↗ jump to hunk
A common usage pattern of open() is to check if it was successful, and die() if it was not: int fd = open(path, O_WRONLY | O_CREAT, 0777); if (fd < 0) die_errno(_("Could not open '%s' for writing."), path); Implement a wrapper function xopen() that does the above so that we can save a few lines of code, and make the die() messages consistent. Signed-off-by: Paul Tan <redacted> --- git-compat-util.h | 1 + wrapper.c | 18 ++++++++++++++++++ 2 files changed, 19 insertions(+)diff --git a/git-compat-util.h b/git-compat-util.h index 17584ad..9745962 100644 --- a/git-compat-util.h +++ b/git-compat-util.h@@ -718,6 +718,7 @@ extern char *xstrndup(const char *str, size_t len); extern void *xrealloc(void *ptr, size_t size); extern void *xcalloc(size_t nmemb, size_t size); extern void *xmmap(void *start, size_t length, int prot, int flags, int fd, off_t offset); +extern int xopen(const char *path, int flags, mode_t mode); extern ssize_t xread(int fd, void *buf, size_t len); extern ssize_t xwrite(int fd, const void *buf, size_t len); extern ssize_t xpread(int fd, void *buf, size_t len, off_t offset);diff --git a/wrapper.c b/wrapper.c index c1a663f..971665a 100644 --- a/wrapper.c +++ b/wrapper.c@@ -189,6 +189,24 @@ void *xcalloc(size_t nmemb, size_t size) # endif #endif
The original open can take 2 or 3 parameters, how about this:
int xopen(const char *path, int oflag, ... )
{
va_list params;
int mode;
int fd;
va_start(params, oflag);
mode = va_arg(params, int);
va_end(params);
fd = open(path, oflag, mode);
+/**
+ * xopen() is the same as open(), but it die()s if the open() fails.
+ */
+int xopen(const char *path, int flags, mode_t mode)
+{
+ int fd;
+
+ assert(path);
+ fd = open(path, flags, mode);
+ if (fd < 0) {
+ if ((flags & O_WRONLY) || (flags & O_RDWR))
+ die_errno(_("could not open '%s' for writing"), path);This is only partly true: it could be either "writing" or "read write". I don't know if the info "for reading" or "for writing" is needed/helpful at all, or if a simple "could not open" would be enough. Another thing: should we handle EINTR ? (Somewhere in the back of my head I remember that some OS returned EINTR when handling some foreign file system Mac OS / NTFS ?)