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author | Sascha Hauer <s.hauer@pengutronix.de> | 2021-04-14 15:23:52 +0200 |
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committer | Sascha Hauer <s.hauer@pengutronix.de> | 2021-04-14 15:46:48 +0200 |
commit | 2154de1cf36c0ac741f258f72de6895e8782ec79 (patch) | |
tree | 059eb2c27be8918d7edf26382912549ec4962e32 /scripts | |
parent | cc9c2d3dd0ee72730dcdb6975da520b13d1ed75c (diff) | |
download | barebox-2154de1cf36c0ac741f258f72de6895e8782ec79.tar.gz barebox-2154de1cf36c0ac741f258f72de6895e8782ec79.tar.xz |
bareboximd: Use mmap when possibly
It's hard to believe but there are systems out there that are so sparse
with memory that they can't afford 1MiB of RAM to read a file into.
Use mmap when possible and fall back to reading into an allocated buffer
otherwise.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Diffstat (limited to 'scripts')
-rw-r--r-- | scripts/bareboximd.c | 53 |
1 files changed, 34 insertions, 19 deletions
diff --git a/scripts/bareboximd.c b/scripts/bareboximd.c index 9558c77d1a..c3dcb4dcf0 100644 --- a/scripts/bareboximd.c +++ b/scripts/bareboximd.c @@ -15,6 +15,7 @@ #include <stdarg.h> #include <linux/err.h> #include <linux/kernel.h> +#include <sys/mman.h> #include "../include/image-metadata.h" @@ -96,29 +97,35 @@ static int read_file_2(const char *filename, size_t *size, void **outbuf, size_t goto close; } - buf = malloc(max_size); - if (!buf) { - fprintf(stderr, "Cannot allocate memory\n"); - ret = -ENOMEM; - goto close; - } + buf = mmap(NULL, max_size, PROT_READ, MAP_SHARED, fd, 0); + if (buf == MAP_FAILED ) { + buf = malloc(max_size); + if (!buf) { + fprintf(stderr, "Cannot allocate memory\n"); + ret = -ENOMEM; + goto close; + } - *outbuf = buf; - while (*size < max_size) { - rsize = read(fd, buf, max_size-*size); - if (rsize == 0) { - ret = -EIO; - goto free; - } else if (rsize < 0) { - if (errno == EAGAIN) - continue; - else { + *outbuf = buf; + + while (*size < max_size) { + rsize = read(fd, buf, max_size - *size); + if (rsize == 0) { + ret = -EIO; + goto free; + } + + if (rsize < 0) { ret = -errno; goto free; } - } /* ret > 0 */ - buf += rsize; - *size += rsize; + + buf += rsize; + *size += rsize; + } + } else { + *outbuf = buf; + *size = max_size; } ret = 0; @@ -131,6 +138,14 @@ close: return ret; } +static inline void read_file_2_free(void *buf) +{ + /* + * Can't free() here because buffer might be mmapped. No need + * to do anything as we are exitting in a moment anyway. + */ +} + static unsigned long simple_strtoul(const char *cp, char **endp, unsigned int base) { return strtoul(cp, endp, base); |