diff options
Diffstat (limited to 'src')
-rw-r--r-- | src/touch.c | 101 |
1 files changed, 74 insertions, 27 deletions
diff --git a/src/touch.c b/src/touch.c index 3b01ab30a..7cf1c1b3f 100644 --- a/src/touch.c +++ b/src/touch.c @@ -102,6 +102,43 @@ static int const time_masks[] = CH_ATIME, CH_ATIME, CH_ATIME, CH_MTIME, CH_MTIME }; +/* Open FILE, possibly creating it. Set *FILE_CREATED to nonzero if the + open creates it, or to zero if the open call opened an existing file. + Return the result of the open call. Be careful to avoid race conditions. */ + +static int +open_maybe_create (const char *file, int *file_created) +{ + int fd; + + *file_created = 0; + while (1) + { + /* First, see if we can create a new FILE. */ + fd = open (file, O_WRONLY | O_CREAT | O_EXCL, 0666); + if (fd != -1) + *file_created = 1; + + /* If the open succeeded or if it failed for any reason other + than the existence of FILE, then we're done. */ + if (fd != -1 || errno != EEXIST) + break; + + /* The first open failed because FILE already exists. + Now try to open it for writing. */ + fd = open (file, O_WRONLY); + + /* If the open succeeded or if it failed for any reason other + than the absence of FILE, then we're done. */ + /* The 2nd open can fail if FILE was unlinked between the two + open calls. When that happens, just iterate. */ + if (fd != -1 || errno != ENOENT) + break; + } + + return fd; +} + /* Update the time of file FILE according to the options given. Return 0 if successful, 1 if an error occurs. */ @@ -111,42 +148,52 @@ touch (const char *file) int status; struct stat sbuf; int fd; + int file_created; - if (stat (file, &sbuf)) + if (no_create) { - if (errno != ENOENT) - { - error (0, errno, "%s", file); - return 1; - } - if (no_create) - return 0; - fd = creat (file, 0666); - if (fd == -1) + /* Try to open an existing FILE. */ + fd = open (file, O_WRONLY); + if (fd == -1 && errno == ENOENT) { - error (0, errno, "%s", file); - return 1; - } - if (amtime_now) - { - if (close (fd) < 0) - { - error (0, errno, "%s", file); - return 1; - } - return 0; /* We've done all we have to. */ - } - if (fstat (fd, &sbuf)) - { - error (0, errno, "%s", file); - close (fd); - return 1; + /* FILE doesn't exist. So we're done. */ + return 0; } + file_created = 0; + } + else + { + /* Try to open FILE, creating it if necessary. */ + fd = open_maybe_create (file, &file_created); + } + + if (fd == -1) + { + error (0, errno, "%s", file); + return 1; + } + + if (file_created && amtime_now) + { if (close (fd) < 0) { error (0, errno, "%s", file); return 1; } + return 0; /* We've done all we have to. */ + } + + if (fstat (fd, &sbuf)) + { + error (0, errno, "%s", file); + close (fd); + return 1; + } + + if (close (fd) < 0) + { + error (0, errno, "%s", file); + return 1; } if (amtime_now) |