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| author | Peter Stephenson <p.stephenson@samsung.com> | 2020-06-09 18:04:46 +0100 |
|---|---|---|
| committer | Peter Stephenson <p.stephenson@samsung.com> | 2020-06-09 18:07:01 +0100 |
| commit | 3df604a4be76db6ccf285eda6b4b3f5f6ec7497d (patch) | |
| tree | 244774fd13ebf129d029f521fa2f8d707763da6f /Src | |
| parent | 172b646a6baa4037a4dbc4d056f2b4b786eea24e (diff) | |
| download | zsh-3df604a4be76db6ccf285eda6b4b3f5f6ec7497d.tar.gz zsh-3df604a4be76db6ccf285eda6b4b3f5f6ec7497d.tar.xz zsh-3df604a4be76db6ccf285eda6b4b3f5f6ec7497d.zip | |
46026: Add CLOBBER_EMPTY option.
Diffstat (limited to 'Src')
| -rw-r--r-- | Src/exec.c | 27 | ||||
| -rw-r--r-- | Src/options.c | 1 | ||||
| -rw-r--r-- | Src/zsh.h | 1 |
3 files changed, 24 insertions, 5 deletions
diff --git a/Src/exec.c b/Src/exec.c index c72d485b2..045b5d2b9 100644 --- a/Src/exec.c +++ b/Src/exec.c @@ -2143,14 +2143,15 @@ clobber_open(struct redir *f) { struct stat buf; int fd, oerrno; + char *ufname = unmeta(f->name); /* If clobbering, just open. */ if (isset(CLOBBER) || IS_CLOBBER_REDIR(f->type)) - return open(unmeta(f->name), + return open(ufname, O_WRONLY | O_CREAT | O_TRUNC | O_NOCTTY, 0666); /* If not clobbering, attempt to create file exclusively. */ - if ((fd = open(unmeta(f->name), + if ((fd = open(ufname, O_WRONLY | O_CREAT | O_EXCL | O_NOCTTY, 0666)) >= 0) return fd; @@ -2158,11 +2159,27 @@ clobber_open(struct redir *f) * Try opening, and if it's a regular file then close it again * * because we weren't supposed to open it. */ oerrno = errno; - if ((fd = open(unmeta(f->name), O_WRONLY | O_NOCTTY)) != -1) { - if(!fstat(fd, &buf) && !S_ISREG(buf.st_mode)) - return fd; + if ((fd = open(ufname, O_WRONLY | O_NOCTTY)) != -1) { + if(!fstat(fd, &buf)) { + if (!S_ISREG(buf.st_mode)) + return fd; + /* + * If CLOBBER_EMPTY is in effect and the file is empty, + * we are allowed to re-use it. + * + * Note: there is an intrinsic race here because another + * process can write to this file at any time. The only fix + * would be file locking, which we wish to avoid in basic + * file operations at this level. This would not be + * fixed. just additionally complicated, by re-opening the + * file and truncating. + */ + if (isset(CLOBBEREMPTY) && buf.st_size == 0) + return fd; + } close(fd); } + errno = oerrno; return -1; } diff --git a/Src/options.c b/Src/options.c index 7586d21d2..fba021e7d 100644 --- a/Src/options.c +++ b/Src/options.c @@ -114,6 +114,7 @@ static struct optname optns[] = { {{NULL, "checkjobs", OPT_EMULATE|OPT_ZSH}, CHECKJOBS}, {{NULL, "checkrunningjobs", OPT_EMULATE|OPT_ZSH}, CHECKRUNNINGJOBS}, {{NULL, "clobber", OPT_EMULATE|OPT_ALL}, CLOBBER}, +{{NULL, "clobberempty", 0}, CLOBBEREMPTY}, {{NULL, "combiningchars", 0}, COMBININGCHARS}, {{NULL, "completealiases", 0}, COMPLETEALIASES}, {{NULL, "completeinword", 0}, COMPLETEINWORD}, diff --git a/Src/zsh.h b/Src/zsh.h index 1f2d774a1..ed123f2b9 100644 --- a/Src/zsh.h +++ b/Src/zsh.h @@ -2378,6 +2378,7 @@ enum { CHECKJOBS, CHECKRUNNINGJOBS, CLOBBER, + CLOBBEREMPTY, APPENDCREATE, COMBININGCHARS, COMPLETEALIASES, |