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authorDenis Vlasenko <vda.linux@googlemail.com>2007-06-13 06:47:47 +0000
committerDenis Vlasenko <vda.linux@googlemail.com>2007-06-13 06:47:47 +0000
commitd67cef2425fb5e75b75d52d9a308da6d29cd7a0d (patch)
tree5d034f518dfae9a933a701e8c42da4acbf0cb42d /libbb
parentf5f75c5e82d47613847c356664e47c4be69e73aa (diff)
downloadbusybox-d67cef2425fb5e75b75d52d9a308da6d29cd7a0d.tar.gz
hush: fix read builtin to not read ahead past eol and to not use
insane amounts of stack. Testsuite updated.
Diffstat (limited to 'libbb')
-rw-r--r--libbb/read.c53
1 files changed, 42 insertions, 11 deletions
diff --git a/libbb/read.c b/libbb/read.c
index c05b26b50..05bf754e0 100644
--- a/libbb/read.c
+++ b/libbb/read.c
@@ -38,10 +38,8 @@ ssize_t full_read(int fd, void *buf, size_t len)
if (cc < 0)
return cc; /* read() returns -1 on failure. */
-
if (cc == 0)
break;
-
buf = ((char *)buf) + cc;
total += cc;
len -= cc;
@@ -64,9 +62,7 @@ void xread(int fd, void *buf, size_t count)
unsigned char xread_char(int fd)
{
char tmp;
-
xread(fd, &tmp, 1);
-
return tmp;
}
@@ -95,6 +91,37 @@ char *reads(int fd, char *buffer, size_t size)
return buffer;
}
+// Read one line a-la fgets. Reads byte-by-byte.
+// Useful when it is important to not read ahead.
+char *xmalloc_reads(int fd, char *buf)
+{
+ char *p;
+ int sz = buf ? strlen(buf) : 0;
+
+ goto jump_in;
+ while (1) {
+ if (p - buf == sz) {
+ jump_in:
+ buf = xrealloc(buf, sz + 128);
+ p = buf + sz;
+ sz += 128;
+ }
+ if (safe_read(fd, p, 1) != 1) { /* EOF/error */
+ if (p == buf) {
+ /* we read nothing [and buf was NULL initially] */
+ free(buf);
+ return NULL;
+ }
+ break;
+ }
+ if (*p == '\n')
+ break;
+ p++;
+ }
+ *p++ = '\0';
+ return xrealloc(buf, p - buf);
+}
+
ssize_t read_close(int fd, void *buf, size_t size)
{
int e;
@@ -113,25 +140,29 @@ ssize_t open_read_close(const char *filename, void *buf, size_t size)
return read_close(fd, buf, size);
}
+// Read (potentially big) files in one go. File size is estimated by
+// lseek to end.
void *xmalloc_open_read_close(const char *filename, size_t *sizep)
{
char *buf;
size_t size = sizep ? *sizep : INT_MAX;
- int fd = xopen(filename, O_RDONLY);
+ int fd;
+ off_t len;
+
+ fd = xopen(filename, O_RDONLY);
/* /proc/N/stat files report len 0 here */
/* In order to make such files readable, we add small const */
- off_t len = xlseek(fd, 0, SEEK_END) + 256;
+ len = xlseek(fd, 0, SEEK_END) | 0x3ff; /* + up to 1k */
xlseek(fd, 0, SEEK_SET);
-
- if (len > size)
- bb_error_msg_and_die("file '%s' is too big", filename);
- size = len;
+ if (len < size)
+ size = len;
buf = xmalloc(size + 1);
size = read_close(fd, buf, size);
if ((ssize_t)size < 0)
bb_perror_msg_and_die("'%s'", filename);
xrealloc(buf, size + 1);
buf[size] = '\0';
- if (sizep) *sizep = size;
+ if (sizep)
+ *sizep = size;
return buf;
}