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Diffstat (limited to 'src/util/readlline.c')
| -rw-r--r-- | src/util/readlline.c | 138 |
1 files changed, 138 insertions, 0 deletions
diff --git a/src/util/readlline.c b/src/util/readlline.c new file mode 100644 index 0000000..015877a --- /dev/null +++ b/src/util/readlline.c @@ -0,0 +1,138 @@ +/*++ +/* NAME +/* readlline 3 +/* SUMMARY +/* read logical line +/* SYNOPSIS +/* #include <readlline.h> +/* +/* VSTRING *readllines(buf, fp, lineno, first_line) +/* VSTRING *buf; +/* VSTREAM *fp; +/* int *lineno; +/* int *first_line; +/* +/* VSTRING *readlline(buf, fp, lineno) +/* VSTRING *buf; +/* VSTREAM *fp; +/* int *lineno; +/* DESCRIPTION +/* readllines() reads one logical line from the named stream. +/* .IP "blank lines and comments" +/* Empty lines and whitespace-only lines are ignored, as +/* are lines whose first non-whitespace character is a `#'. +/* .IP "multi-line text" +/* A logical line starts with non-whitespace text. A line that +/* starts with whitespace continues a logical line. +/* .PP +/* The result value is the input buffer argument or a null pointer +/* when no input is found. +/* +/* readlline() is a backwards-compatibility wrapper. +/* +/* Arguments: +/* .IP buf +/* A variable-length buffer for input. The result is null terminated. +/* .IP fp +/* Handle to an open stream. +/* .IP lineno +/* A null pointer, or a pointer to an integer that is incremented +/* after reading a physical line. +/* .IP first_line +/* A null pointer, or a pointer to an integer that will contain +/* the line number of the first non-blank, non-comment line +/* in the result logical line. +/* DIAGNOSTICS +/* Warning: a continuation line that does not continue preceding text. +/* The invalid input is ignored, to avoid complicating caller code. +/* SECURITY +/* .ad +/* .fi +/* readlline() imposes no logical line length limit therefore it +/* should be used for reading trusted information only. +/* LICENSE +/* .ad +/* .fi +/* The Secure Mailer license must be distributed with this software. +/* AUTHOR(S) +/* Wietse Venema +/* IBM T.J. Watson Research +/* P.O. Box 704 +/* Yorktown Heights, NY 10598, USA +/*--*/ + +/* System library. */ + +#include <sys_defs.h> +#include <ctype.h> + +/* Utility library. */ + +#include "msg.h" +#include "vstream.h" +#include "vstring.h" +#include "readlline.h" + +#define STR(x) vstring_str(x) +#define LEN(x) VSTRING_LEN(x) +#define END(x) vstring_end(x) + +/* readllines - read one logical line */ + +VSTRING *readllines(VSTRING *buf, VSTREAM *fp, int *lineno, int *first_line) +{ + int ch; + int next; + ssize_t start; + char *cp; + + VSTRING_RESET(buf); + + /* + * Ignore comment lines, all whitespace lines, and empty lines. Terminate + * at EOF or at the beginning of the next logical line. + */ + for (;;) { + /* Read one line, possibly not newline terminated. */ + start = LEN(buf); + while ((ch = VSTREAM_GETC(fp)) != VSTREAM_EOF && ch != '\n') + VSTRING_ADDCH(buf, ch); + if (lineno != 0 && (ch == '\n' || LEN(buf) > start)) + *lineno += 1; + /* Ignore comment line, all whitespace line, or empty line. */ + for (cp = STR(buf) + start; cp < END(buf) && ISSPACE(*cp); cp++) + /* void */ ; + if (cp == END(buf) || *cp == '#') + vstring_truncate(buf, start); + else if (start == 0 && lineno != 0 && first_line != 0) + *first_line = *lineno; + /* Terminate at EOF or at the beginning of the next logical line. */ + if (ch == VSTREAM_EOF) + break; + if (LEN(buf) > 0) { + if ((next = VSTREAM_GETC(fp)) != VSTREAM_EOF) + vstream_ungetc(fp, next); + if (next != '#' && !ISSPACE(next)) + break; + } + } + VSTRING_TERMINATE(buf); + + /* + * Invalid input: continuing text without preceding text. Allowing this + * would complicate "postconf -e", which implements its own multi-line + * parsing routine. Do not abort, just warn, so that critical programs + * like postmap do not leave behind a truncated table. + */ + if (LEN(buf) > 0 && ISSPACE(*STR(buf))) { + msg_warn("%s: logical line must not start with whitespace: \"%.30s%s\"", + VSTREAM_PATH(fp), STR(buf), + LEN(buf) > 30 ? "..." : ""); + return (readllines(buf, fp, lineno, first_line)); + } + + /* + * Done. + */ + return (LEN(buf) > 0 ? buf : 0); +} |