This loop was using the number of bytes read from the file as condition
to keep reading.
From Linux's fread(3) man page:
> On success, fread() and fwrite() return the number of items read or
> written. This number equals the number of bytes transferred only when
> size is 1. If an error occurs, or the end of the file is reached, the
> return value is a short item count (or zero).
>
> The file position indicator for the stream is advanced by the number
> of bytes successfully read or written.
>
> fread() does not distinguish between end-of-file and error, and
> callers must use feof(3) and ferror(3) to determine which occurred.
This means that nread!=0 doesn't make much sense as an end condition for
the loop: nread==0 doesn't necessarily mean that EOF has been reached or
an error has occured (but that is usually the case) and nread!=0 doesn't
necessarily mean that EOF has not been reached or that no read errors
have occured. feof(3) and ferror(3) should be uses when using fread(3).
Currently curl has to performs an extra fread(3) call to get a return
value equal to 0 to stop looping.
This usually "works" (even though nread==0 shouldn't be interpreted as
EOF) if stdin is a pipe because EOF usually marks the "real" end of the
stream, so the extra fread(3) call will return immediately and the extra
read syscall won't be noticeable:
bash-5.1$ strace -e read curl -s -F file=@- 0x0.st <<< a 2>&1 |
> tail -n 5
read(0, "a\n", 4096) = 2
read(0, "", 4096) = 0
read(0, "", 4096) = 0
http://0x0.st/oRs.txt
+++ exited with 0 +++
bash-5.1$
But this doesn't work if curl is reading from stdin, stdin is a
terminal, and the EOF is being emulated using a shell with ^D. Two
consecutive ^D will be required in this case to actually make curl stop
reading:
bash-5.1$ curl -F file=@- 0x0.st
a
^D^D
http://0x0.st/oRs.txt
bash-5.1$
A possible workaround to this issue is to use a program that handles EOF
correctly to indirectly send data to curl's stdin:
bash-5.1$ cat - | curl -F file=@- 0x0.st
a
^D
http://0x0.st/oRs.txt
bash-5.1$
This patch makes curl handle EOF properly when using fread(3) in
file2memory() so that the workaround is not necessary.
Since curl was previously ignoring read errors caused by this fread(3),
ferror(3) is also used in the condition of the loop: read errors and EOF
will have the same meaning; this is done to somewhat preserve the old
behaviour instead of making the command fail when a read error occurs.
Closes#8701
- replace tabs with spaces where possible
- remove line ending spaces
- remove double/triple newlines at EOF
- fix a non-UTF-8 character
- cleanup a few indentations/line continuations
in manual examples
Closes https://github.com/curl/curl/pull/3037
Make the number parser aware of the maximum limit curl accepts for a
value and return an error immediately if larger, instead of running an
integer overflow later.
Fixes#1730Closes#1736
- Add new option CURLOPT_DEFAULT_PROTOCOL to allow specifying a default
protocol for schemeless URLs.
- Add new tool option --proto-default to expose
CURLOPT_DEFAULT_PROTOCOL.
In the case of schemeless URLs libcurl will behave in this way:
When the option is used libcurl will use the supplied default.
When the option is not used, libcurl will follow its usual plan of
guessing from the hostname and falling back to 'http'.
Added initial support for --next/-: which will be used to replace the
rather confusing : command line operation what was used for the URL
specific options prototype.
In preparation for separating the global config options from the per
operation config options, reworked the list engines code to not use a
member variable in the Configurable structure.
1 - str2offset() no longer accepts negative numbers since offsets are by
nature positive.
2 - introduced str2unum() for the command line parser that accepts
numericals which are not supposed to be negative, so that it will
properly complain on apparent bad uses and mistakes.
Bug: http://curl.haxx.se/mail/archive-2012-07/0013.html
Configuration files such as curl_config.h and all config-*.h no longer exist
nor are generated/copied into 'src' directory, now these only exist in 'lib'
directory from where curl tool sources uses them.
Additionally old src/setup.h has been refactored into src/tool_setup.h which
now pulls lib/setup.h
The possibility of a makefile needing an include path adjustment exists.
